RU2326133C2 - Method of obtaining aromatic polycarbonate - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention pertains to the method of obtaining aromatic carbonate. The method involves the stage of obtaining diphenyl carbonate, on which phenol and at least one carbonyl compound are used as the raw materials, and/or a stage for obtaining diphenol A, on which phenol and acetone are used as the raw materials; and a stage for obtaining the aromatic polycarbonate, on which diphenyl carbonate and diphenol A are used as the raw materials, as a result of the polymerisation stage of the aromatic carbonate. The phenol by-product is extracted. It is distinct in that, its water content has mass percentage ratio of 0.2% or less, and the phenol is used as the raw material during the stage of obtaining diphenyl carbonate and/or the stage of obtaining diphenol A. The carbonyl compound is in form of phosgene, carbon monoxide or dialkylcarbonate.

EFFECT: solving the problem of the phenol by-product obtained during the stage of obtaining polycarbonate; efficiency of obtaining aromatic polycarbonate.

43 cl, 5 ex

Description

Technical field

The present invention relates to a method for producing aromatic polycarbonate.

State of the art

Aromatic polycarbonates (hereinafter abbreviated as PC) are generally obtained by carrying out a polymerization reaction between diphenyl carbonate (hereinafter abbreviated as DPC) and bisphenol A (hereinafter abbreviated as VRA).

Processing of phenol by-product

During the polymerization reaction, phenol is formed as a by-product (hereinafter, abbreviated as “PL”). This PL by-product as an impurity contains DPC, BPA, oligomers resulting from a reaction involving one to seven DPC molecules and one to seven BPA molecules, and the like. The method by which this by-product PL is returned to the BPA production step or to the DPC production step is known.

Namely, the method by which the PL by-product is returned to the BPA stage as such or after purification to a low degree of purity is described in Patent Document 1. The reason why the PL obtained as a by-product may be characterized by a low degree of purity is that even if the DPC and oligomers are hydrolyzed to obtain PL and BPA, and these compounds go to the step of obtaining BPA, this will not be a problem.

In addition, the method by which the PL by-product is purified to a high degree of purity and then returned to the DPC production step is described in Patent Document 2, Patent Document 3 and the following. The reason why PL obtained as a by-product should be characterized by a high degree of purity is because it is necessary to prevent the entry of BPA and the like into the DPC production step and clogging.

The connection stages of obtaining

Usually use solid BPA, which is obtained by cooling the BPA in the molten state after cleaning. However, if the apparatus for producing BPA is installed near the apparatus for producing RS, the BPA in the molten state as such or in the form of a solution formed by a BPA / PL mixture characterized by a specific composition can be fed into the apparatus for producing RS and polymerized. This method eliminates the need for re-heating or purification and leads to an improved thermal coefficient of performance.

Waste solution recycling

In addition, each of the stages of obtaining DPC and BPA and the stage of obtaining RS as a result lead to the production of an spent solution containing a large amount of organic compounds.

Specifically, firstly, at the stage of obtaining RS, the formation of the spent solution occurs as follows. In the main step, in which DPC and BPA are used as starting materials for the production of RS from the polymerization step, the ingredients converted to steam in the polymerization step are liquefied and subjected to the distillation step to recover PL, and the resulting distillation residue is a waste solution. This distillation residue contains PL, DPC, BPA, oligomers derived from several molecules combined from DPC and BPA, and the like, and the extraction of these ingredients has a significant effect on PC yield.

In this regard, the method by which the residue after distillation is returned to the polymerization step is described in Patent Document 3 and Patent Document 4, and the method by which the residue after distillation is subjected to distillation again to extract the ingredients, and the resulting residue after extraction / distillation used as fuel, is described in patent document 1.

In the DPC production step, in the main step in which PL and the carbonyl compound are used as starting materials in the production of DPC, as a result of the reaction step and the distillation step, the distillation residue resulting from the distillation step is a spent solution. This distillation residue contains DPC, and its recovery has a significant effect on the yield of DPC.

In this regard, the method by which the residue after distillation is subjected to distillation again to extract the DPC, and this DPC is returned to the liquid reaction mixture resulting from the reaction step, is described in patent document 5.

In addition, at the stage of obtaining BPA, the main stage in which PL and acetone are used as starting materials in the production of BPA as a result of the synthesis reaction stage, crystallization stage and solid / liquid phase separation stage, yields the mother liquor resulting from solid / liquid phase separation steps. As described in Patent Document 6, this mother liquor, in addition to a large amount of PL and BPA, contains by-products, such as the 2,4-isomer, trisphenols and chroman derivatives, and also contains colored impurities and coloring impurities in a small amount. Since this mother liquor contains PL and BPA, which are the starting materials for obtaining BPA, organize its circulation through all stages and reuse. However, in the event that the entire amount of the mother liquor is circulated without processing, then by-products and colored impurities and coloring impurities will accumulate. Therefore, these by-products and impurities must be removed.

Vacuum device

In the preparation step, the DPCs are purified by distillation under reflux conditions. In the production step, PC PLs are removed by separating it from the DPC by distillation. These distillation operations are carried out under reduced pressure using a vacuum device in order to reduce the distillation temperature (see Patent Document 7).

[Patent Document 1] JP-A-2000-53759

[Patent Document 2] JP-A-10-60106

[Patent Document 3] JP-A-9-255772

[Patent Document 4] JP-A-9-165443

[Patent Document 5] JP-A-2002-322130

[Patent Document 6] JP-A-5-331088

[Patent Document 7] JP-A-9-38402

Description of the invention

[Processing of phenol by-product; the problem of integrating the three stages of production]

However, in each of the cases described above, no studies were conducted regarding the level of water, despite the fact that levels of impurities other than water, such as, for example, BPA and DPC, were paid attention. The phenol by-product is accompanied by water contained in DPC and BPA used as starting materials in the polymerization, in particular in those substances that were cured and thus contain water, and water supplied together with the polymerization catalyst. At the stage of BPA production, the presence of water leads to a decrease in catalytic activity, which reduces the conversion. At the stage of obtaining DPC, the presence of water leads not only to a decrease in catalytic activity, but also to hydrolysis of the resulting DPC.

In addition, phenol, a by-product obtained in the polymerization step in the preparation of RS, contains the above impurities. These by-products include impurities that are not problematic even if they are supplied to the DPC production step, but cause problems if they are supplied to the BPA production step. By-products also include impurities that act in reverse.

In addition, as indicated above, it is necessary to carry out the stage of removing water from the ingredients isolated in the form of distillate at the polymerization stage in the preparation of RS and including phenol as the main component. However, in the event that the stage of obtaining DPC, the stage of obtaining BPA and the stage of obtaining RS are integrated in such a way as to carry them out in one place, then two or more than two stages will be organized to remove water, because the stage of obtaining BPA also includes exactly such same stage.

The connection stages of obtaining

At the crystallization stage of the obtained BPA, at the stage of obtaining the BPA, the solid phase tends to form deposits on those parts of the crystallizer and other elements that come into contact with the liquid. Thus, it will be necessary to stop carrying out this stage and perform cleaning at intervals of several months. For this reason, these stages at the stage of obtaining BPA, which is concluded between the stage of the synthesis reaction and the crystallization stage, are carried out alternately.

In contrast to this stage of obtaining DPC, the problem described above is not typical, and DPC can be obtained continuously. For this reason, in the case of storing BPA in the required amount while maintaining the BPA in the molten state, polymerization upon receipt of RS can be carried out continuously.

However, if the BPA is kept in a molten state, it tends to undergo yellowing, decomposition, and the like, and this affects the quality of the resulting RS.

Waste solution recycling

In addition, since the distillation residue resulting from the MS production step contains PL, the return of the entire amount of the residue to the polymerization stage will affect the rate of initial polymerization, since PL is present there from the start of polymerization. In addition, since the residue after distillation resulting from the stage of obtaining MS is generally colored, sending this residue for recycling without any processing leads to a colored product of MS. Even though the residue after distillation is subjected to distillation again, the resulting residue after extraction / distillation also contains these ingredients in small amounts. Therefore, discarding this residue without any processing not only affects the production efficiency, but also becomes the source of the problem associated with the appearance of environmental stress.

In addition, the distillation residue resulting from the DPC production step is usually discarded as such. Since this residue after distillation still contains DPC, discarding the residue without any processing not only affects the production efficiency, but can also become a source of environmental problems.

Vacuum device

In addition, if the distillation is carried out under reduced pressure, then there are times when the distillate ingredients, such as PL and DPC, are removed using a vacuum device to obtain a liquid mass, partially remaining in the pipe leading to the vacuum device, or the remaining distillate ingredients will harden, which will make it impossible to maintain a state of vacuum. In addition, in the case where ingredients that are isolated as distillate, such as PL and DPC, are pumped as reflux, it is likely that the reflux pipe may become clogged, for example, because such distillate ingredients in the pipe solidify .

Accordingly, an object of the invention is to provide a method for managing phenol, a by-product, in which the water content of the PL by-product obtained in the PC production step is limited to a value in a predetermined range, thereby ensuring production efficiency at the stage of obtaining BPA and the stage of obtaining DPC, which serves as a by-product of PL, as a result of which the combined effectiveness of obtaining MS is maintained.

Another goal is to save labor costs for processing in the form of purification in relation to the phenol by-product obtained in the polymerization step in the preparation of aromatic polycarbonate, by supplying phenol as the by-product to the diphenyl carbonate production step or the bisphenol A production step in accordance with impurities contained in phenol.

And another goal relates to the problem of integrating the three stages of production and is to save labor costs for refining in the form of purification of distillate ingredients, which contain phenol as the main ingredient and are formed at the polymerization stage when receiving aromatic polycarbonate, as a result of using the existing stages, used to produce diphenyl carbonate and bisphenol A.

An additional goal relates to the connection of the stages of receipt and is to propose a method of connecting the stages of obtaining, which is able to provide the creation of a method for producing RS with sufficient quality.

Another additional objective relates to a method for processing the spent solution and is to improve the overall efficiency and reduce the environmental burden resulting from the return of the residue after distillation resulting from the stage of obtaining DPC, and the residue after distillation resulting from the stage of obtaining RS, to special sections of the stages of obtaining RS.

And another additional goal relates to the stages of distillation and is to suppress the formation of liquid mass or solidification in pipelines in the apparatus, in which PL or DPC is isolated in the form of distillate.

As a method for managing phenol, a by-product, the invention provides a method for producing aromatic polycarbonate (PC), which comprises a step for producing diphenyl carbonate (DPC), in which phenol (PL) and at least one carbonyl compound are used as starting materials for the production of diphenyl carbonate (DPC), and / or a step for producing bisphenol A (BPA), in which phenol (PL) and acetone are used as starting materials for producing bisphenol A (BPA), and a step for producing aromatic poly carbonate (PC), on which diphenyl carbonate (DPC) and bisphenol A (BPA) are used as starting materials in the preparation of aromatic polycarbonate (PC) as a result of the polymerization step in the production of PC, and the phenol which is a by-product is recovered, characterized in that the water contained in the phenol by-product recovered in the aromatic polycarbonate (PC) production step is held at 0.2 wt% or less, and this phenol is used as part of the starting material in the step of radiation of diphenyl carbonate (DPC) and / or a step for producing bisphenol A (BPA).

The phenol used as starting material in the diphenyl carbonate (DPC) production step may be phenol (PL) containing cresol and / or xylenol in an amount of 20-1000 ppm (wt.), And phenol (PL) obtained in the step polymerization at the stage of obtaining aromatic polycarbonate (PC), can be used as at least part of the phenol used as starting material in the stage of obtaining bisphenol A (BPA).

In addition, the method may differ in that 50-95 wt.% Of phenol obtained as a by-product at the stage of production of aromatic polycarbonate is used as at least part of phenol used in the stage of production of diphenyl carbonate, and 50-5 wt. .% it is used as at least part of the starting material for the stage of obtaining bisphenol A.

As for the connection of the stages, the method can be characterized by the fact that before and / or after the stage of distillation of PL, a storage stage is carried out upon receipt of MS, which stores the liquefied, steam-converted ingredients upon receipt of MS, intended for the stage of distillation of PL, and / or a phenol by-product recovered in the PL distillation step, in that after the distillation step in the production of DPC, a DPC storage step is carried out in which the diphenyl carbonate obtained in the distillation step in the production of DPC is stored and / or and the fact that the storage stage of the BPA, in which the mixture of bisphenol A and phenol is stored, is carried out in the interval between the crystallization / isolation of the BPA and the polymerization step in the preparation of RS. This method is characterized in that the storage tanks used at the respective stages of storage, in accordance with need, are characterized by specific capacities shown below.

10 (Vc / Fc) (1)

(In the expression (1) Vc denotes the capacity (m ³ ) of the storage tank when receiving RS, and Fc denotes the flow (m ³ / h) of liquefied, converted into steam ingredients when receiving RS or is a by-product of phenol)

10 (Vd / Fd) (2)

(In the expression (2), Vd means the capacity (m ³ ) of the storage tank upon receipt of the DPC, and Fd means the flow rate (m ³ / h) of diphenyl carbonate)

10 (Vb / Fb) (3)

(In the expression (3), Vb denotes the capacity (m ³ ) of the storage tank upon receipt of BPA, and Fb denotes the flow rate (m ³ / h) of bisphenol A supplied to the polymerization step upon receipt of RS)

Regarding the methods for processing waste water, the method can be characterized by the fact that the residue after distillation of PL is fed to the stage of distillation upon receipt of DPC and / or the stage of extraction / distillation upon receipt of DPC, so that the residue after distillation of PL and / or at least , any representative selected from the distillation residue upon receipt of DPC and the residue after extraction / distillation upon receipt of DPC is fed to the mother liquor processing step upon receipt of BPA, or by the fact that the residue after distillation PL is fed to the distillation stage upon DPC teachings and / or the step of extracting / obtaining distillation under DPC, and subsequently the residue after distillation in the preparation of DPC and / or the residue after extraction / distillation is fed to DPC obtaining step of processing the mother liquor in the preparation of BPA.

In addition, with regard to the distillation stages, the method can be characterized in that the distillation column at the distillation stage upon receipt of the DPC or distillation stage PL is equipped with a condenser for condensing the distillate, a vacuum device to reduce the pressure in the system, and a vacuum pipe that connects the condenser to the vacuum device , and the fact that the vacuum pipe is inclined downward from the side of the condenser to the side of the vacuum device, and the total height of the parts rising up from the side of the condenser e vacuum device is about 1 m or less.

Brief Description of the Drawings

Figure 1 is a flowchart showing an example of a step for producing a DPC according to the invention.

Figure 2 is a flowchart showing an example of a step for producing a BPA according to the invention.

FIG. 3 is a flowchart illustrating an example of a water separation step (step (b-2)) in a step for producing a BPA according to the invention.

Fig. 4 is a flowchart showing an example of a mother liquor processing step (step (g)) in the step for producing an BPA according to the invention.

FIG. 5 is a flowchart illustrating an example of a step for producing a PC of the invention.

6 is a flowchart showing another example of a step for producing a PC according to the invention.

Fig. 7 is a flowchart illustrating an example of a case in which a DPC production step, a BPA production step and a PC production step according to the invention include a storage step upon receipt of DPC, a storage step upon receipt of BPA and a storage step upon receipt of PC.

Fig. 8 is a flowchart showing an example of an embodiment in which, in the DPC production step, the BPA production step, and the PC production step of the invention, the residue after distillation of PL (X2) is fed to said step, the residue after distillation in the production of DPC (X1) and the residue after extraction / distillation upon receipt of DPC (X1 ').

Fig. 9 is a view illustrating a reflux apparatus in accordance with the invention.

The item numbers and symbols in the drawings have the following meanings: 1 — DPC production reactor, 2 — dehydrochlorination column, 3 — mixing tank, 4 — alkaline neutralization tank, 5 — water washing tank, 6 — first distillation column upon receipt of DPC, 7 — column the second distillation upon receipt of the DPC, 8 — the recovery / distillation column upon receipt of the DPC, 11 — the reservoir for the recovered PL upon receipt of the BPA, 12 — the separation column PL, 13 — the phenol evaporator, 14 — the residue processing reactor, 15 — the regeneration reactor, 21 — mixing tank, 22 - per the first polymerization reactor, 23 - the second polymerization reactor, 24 - the third polymerization reactor, 25 - the fourth polymerization device, 26 - the heat exchanger, 27 - the heat exchanger, 28 - the condenser, 29 - the reservoir for the extracted PL upon receipt of the PC, 29a - the first reservoir for the extracted PL upon receipt of the PC, 29b — the second reservoir for the recovered PL upon receipt of the PC, 30 — the column of the first distillation PL, 31 — the column of the second distillation PL, 32 — the extruder, 33a and 33b — the reflux apparatus, 41 — the distillation column, 42 — the condenser, 43 - vacuum device, 44 - vacuum pipe, 45 - tank d i condensate, 46 - pump for supplying fluid, 47 - reflux pipeline, 48 - mist eliminator, 49 - drainage hole, 50 - supply hole, 51 - valve, 52 - valve, 53 - drainage hole, 54 - drainage hole, 55 - supply hole, 56 - valve, 57 - outlet, A - acetone, BPA - bisphenol A, C1 - alkaline catalyst, C2 - main catalyst, CDC - phosgene, D1 - gaseous hydrochloric acid, D2 - neutralized waste water, D3 - waste water , D4 - low-boiling distillate upon receipt of BPA, D5 - discharged gas, D6 - low-boiling distillate they are poured upon receipt of RS, D7 is an spent solution, AW is a water / acetone mixture, DPC is diphenyl carbonate, E1 is an alkaline aqueous solution, F is a mixed gas, I is an acid, J is an additive, p is the steam-converted ingredients upon receipt of RS, p1 - the first steam-converted ingredients in the production of PC, p2 - the second steam-converted ingredients in the production of PC, PL - phenol, s-PL - phenol, which is a by-product, W - water, X1 - residue after distillation in the production of DPC, X1 'is the residue after isolation / distillation, X2 is the residue after distillation PL, symbol a is a liquid reaction mixture containing DPC, b - dehydrochlorinated liquid, d - recovered liquid containing DPC, e - neutralized liquid, f - water-washed liquid, g - residue after the first distillation, k - recovered liquid PL, p - steam-converted ingredients upon receipt RS, and q is the remainder of the first stage.

The best way to implement the invention

Embodiments of the invention will be described in detail below.

A process for producing aromatic polycarbonate (PC) according to the invention is a process in which diphenyl carbonate (DPC) and bisphenol A (BPA) are polymerized to produce a polymer.

Stage DPC

DPCs are prepared from PL and at least one carbonyl compound as starting materials. There are no restrictions on this carbonyl compound used as long as it can form a carbonyl group of the DPC. Examples of this carbonyl compound include phosgene (hereinafter abbreviated as "CDC"), carbon monoxide, dialkyl carbonates and the like. The following are explanations with respect to the step in which CDC is used as the carbonyl compound in the preparation of the DPC resulting from the washing step of the DPC and the distillation step in the production of DPC after the reaction.

The stage of obtaining DPC is the method shown in figure 1. Namely, a reaction step is carried out in the preparation of DPC, in which PL and CDC are used as starting materials and introduced into the reactor for producing DPC 1 together with an alkaline catalyst (C1), for example pyridine. Despite the fact that there are no particular restrictions on the reaction conditions at this stage, it is preferable to carry out the reaction under conditions at 50-180 ° C and normal pressure when PL is in the molten state. The ratio between the amounts of PL and CDC in the mixture (molar ratio) is preferably such that the amount of CDC is 0.40-0.49 mol per mol of PL from the point of view of complete consumption of CDC.

The liquid reaction mixture containing DPC, a, obtained as a result of carrying out the reaction step upon receipt of DPC, is fed to dehydrochlorination column 2, where the dehydrochlorination step is carried out. Hydrochloric acid gas (D1) obtained in the DPC production reactor 1 and dehydrochlorination column 2 is recovered and fed to the hydrochloric acid processing step (not shown).

Thereafter, the obtained dehydrochlorinated liquid b is subjected to the DPC washing step. This DPC washing step is comprised of a neutralization step and a water wash step, which are described below. Namely, a neutralization step is carried out, in which the dehydrochlorinated liquid b is supplied to the mixing tank 3, and then to the alkaline neutralization tank 4 to neutralize under the action of an alkaline aqueous solution (E1) of hydrochloric acid that remains not removed in the dehydrochlorination column. The neutralized wastewater (D2) produced here is fed to the wastewater treatment step (not shown) to extract the effective organic ingredients contained therein, and then the activated sludge is recycled.

After that, the stage of water washing with DPC is carried out, in which the obtained neutralized liquid, e, is fed into the tank of water washing 5 and washed with water (W). The waste water (D3) discharged at this stage of the water washing of the DPC can be reused as an alkaline diluent in the production of an alkaline aqueous solution (E1) for use in the neutralization step.

The water-washed liquid, f, obtained in the water-washing step of the DPC, is fed to a distillation column where the distillation step is carried out to obtain the DPC. Although three distillation columns are used in FIG. 1, the stage is not limited to this mode. In the case of using three distillation columns, the first distillation column in the preparation of DPC 6 is used to recover mixed gas (F) containing water, PL and an alkaline catalyst. This mixed gas (F) can be divided into these ingredients, which can be reused in the reaction system.

The residue after the first distillation g, discharged from the first distillation column upon receipt of DPC 6, is again subjected to distillation in the second distillation column upon receipt of DPC 7 to recover the purified DPC, which is a product, as a distillate.

There are no particular restrictions on the distillation conditions for the first distillation column upon receipt of DPC 6 until water, alkaline catalyst and PL are distilled off and DPC remains. A pressure of 1.3-13 kPa is preferred. The temperature used is the boiling point at a given pressure. On the other hand, the distillation conditions for the second distillation column upon receipt of DPC 7 are not particularly limited until the DPC is distilled off, and impurities with boiling points higher than the boiling point of DPC remain. Preferred are a pressure of 1.3-6.5 kPa and a temperature of 150-220 ° C.

Incidentally, the distillation residue upon receipt of DPC X1, discharged from the second distillation column upon receipt of DPC 7, contains impurities mainly containing methyl substituted derivatives of DPC resulting from the reaction with methyl phenol, which is a phenol-containing impurity, and brominated substituted derivatives of DPC obtained as a result of reaction with bromine remaining in the CDC. However, this residue after distillation X1, in addition, contains the DPC itself. Therefore, this residue after distillation upon receipt of DPC X1 can again be distilled to recover diphenyl carbonate (DPC). In this case, the distillation residue upon receipt of DPC X1 is subjected to the extraction / distillation step using the extraction / distillation column upon receipt of DPC 8, as shown in FIG. Thus, as a result of the distillation, it is possible to recover the recovered liquid containing DPC, d. From the bottom residue in the distillation column, the residue is recovered after extraction / distillation to obtain DPC (X1 ′), in which methyl substituted and brominated substituted DPC derivatives are concentrated.

The distillation conditions for the recovery / distillation column upon receipt of DPC 8 are not particularly limited as long as the DPC is distilled off and impurities characterized by a boiling point higher than the boiling point of the DPC remain. Preferred are a pressure of 1.3-6.5 kPa and a temperature of 150-220 ° C.

Since the recovered liquid containing DPC, d, which is the distillate from the recovery / distillation column upon receipt of the DPC, is a large quantity of DPC containing ingredient, it is supplied to the mixing tank 3. Thus, the DPC can be recycled to the washing step distillation, and the recovery efficiency of diphenyl carbonate (DPC) can be further improved.

The stage of obtaining BPA

The stage of obtaining BPA is the method shown in figure 2. Namely, PL and acetone (A) as starting materials in the production of BPA as a result of carrying out the reaction step in the production of BPA (step (a)), the removal step of low boiling compounds in the production of BPA (step (b)), the crystallization / isolation step of BPA (step (c)), a heating / melting step (step (d)), a PL removal step (step (e)), and a granulation step (step (f)).

Further separately, individual stages will be explained.

Step (a) is a step in which PL and acetone (A) are subjected to a condensation reaction in the presence of an acid catalyst to give BPA. PL and acetone (A), used in this case as starting materials, are reacted under such conditions when the amount of PL will exceed the stoichiometric amount. The molar ratio between PL and acetone (A), expressed through the ratio of the amounts of PL / acetone (A), is in the range of 3-30, preferably 5-20. The reaction is carried out at a temperature generally in the range of 30-100 ° C, preferably 50-90 ° C, and the pressure in the General case is in the range from normal pressure to 5 kg / cm ² gauge pressure.

As an acid catalyst, it is possible to use an inorganic acid, for example hydrochloric acid, an organic acid, an ion exchange resin, and the like. In the event that an ion exchange resin is used as the acid catalyst, then a cation exchange resin in the form of a sulfonic acid of the gel type, which is characterized by a degree of crosslinking of 1-8%, preferably 2-6%, will be suitable. However, the ion exchange resin is not particularly limited. Hydrochloric acid can also be used as an acid catalyst.

Although the cation exchange resin in the form of a sulfonic acid can be used as such, it is also possible to use a cation exchange resin with a sulfonic acid, which has been modified according to need. Examples of compounds used for modification include compounds having a mercapto group.

As such a compound having a mercapto group, it is possible to use any of the compounds that are known for their applicability in this application, such as aminoalkanethiols, for example 2-aminoethanethiol, ω-pyridylalkanethiols, for example 2- (4-pyridyl) ethanethiol, and thiazolidine compounds they easily acquire a mercapto group during hydrolysis and the like, for example 2,2-dimethylthiazolidine.

The reaction mixture resulting from the reaction step (a), in addition to BPA, generally contains unreacted PL, unreacted acetone (A), a catalyst and water (W) obtained during the reaction, and in addition to In addition, it contains by-products, including colored substances.

Step (b) is a step in which low boiling ingredients are removed from the liquid reaction mixture obtained in step (a) in the preparation of a BPA and a catalyst, for example hydrochloric acid. The low boiling ingredients in the preparation of BPA include water W obtained from the reaction, unreacted acetone (A) and substances having a boiling point close to their boiling points. At this stage, these low boiling ingredients are removed from the reaction mixture by, for example, vacuum distillation, and solid ingredients, such as a catalyst, are removed, for example, by filtration. In the case of a reactor including a fixed catalyst bed, removal of the catalyst is not particularly necessary. When conducting vacuum distillation, it is preferable to use pressure and temperature in the ranges of 50-300 mm Hg and 70-130 ° C, respectively. There are cases in which unreacted PL forms an azeotrope, and part of it is removed from the system.

The low boiling point distillate in the production of BPA (D4), converted to steam in step (b), contains water and a small amount of acetone (A) and phenol (PL). As shown in FIG. 3, this low boiling point distillate upon receipt of BPA (D4) is fed to a PL 12 recovery column, where, optionally, using an extractant, a water separation step is carried out (stage (b-2)), in which PL is recovered through the cube of the column. The recovered liquid PL k obtained at this stage of water separation is stored in the recovered PL 11 reservoir upon receipt of the BPA. Processing the water / acetone AW mixture recovered through the top of the PL 12 recovery column is carried out separately.

Step (c) is a step in which the liquid mixture obtained in step (b) is cooled until a mixture of BPA and PL is precipitated and thus the mixture is isolated. Before carrying out this step (c), the concentration of BPA in the liquid mixture obtained in step (b) can be maintained at a level of 10-50 wt.%, Preferably 20-40 wt.%, By distillation or addition of PL. This operation is preferred because it increases the yield of the adduct, and is effective in controlling the apparent viscosity of the suspension mixture to improve processability. Examples of a mixture of BPA and PL include BPA and PL adduct crystals and simple mixtures between BPA crystals and PL crystals.

The cooling in step (c) is generally carried out to a temperature of 45-60 ° C., resulting in the isolation of crystals of the BPA / PL adduct or crystals of each compound, and the system becomes a suspension. This cooling is carried out using a heat exchanger located outside the system, or as a result of heat removal using the latent heat of vaporization of water added to the mold. After that, this liquid suspension is subjected to filtration, separation by centrifugation method and the like for its separation into crystals and mother liquor containing by-products. The crystals are subjected to the next step. To provide additional improvement in yield, part or all of the allocated mother liquor is recycled to step (a) through the mother liquor processing step to obtain BPA (g), which will be described later, and used as part or all of the amount of PL used as source material.

Step (d) is a step in which the crystals obtained in step (c) are heated and melted. Adduct crystals are generally characterized by a composition in which the BPA content is in the range of 45-70 wt.%, And the PL content is in the range of 55-30%. These crystals are melted by heating to 100-160 ° C, and then subjected to the next step.

Step (e) is a step in which PL is removed from the melt obtained in step (d), thereby obtaining a BPA melt. Vacuum distillation or another technique is used to remove PL from the melt obtained in step (d), and thus dissociate the adduct. Thus, high purity BPA can be extracted. Preferably, this vacuum distillation would be carried out at a pressure of 10-100 mm Hg and a temperature that is in the range of 150-220 ° C and at least 10 ° C higher than the melting point of the mixture of bisphenol A (BPA) / phenol ( PL) present in the system. A technique has also been proposed in which steam stripping is carried out in addition to vacuum distillation to remove residual PL.

Step (f) is a step in which the molten BPA obtained in step (e) is cooled / cured and granulated to obtain a granular product. When using a granulator, for example, a spray dryer, the molten BPA is formed into droplets and cooled / solidified to obtain a product. Drops are obtained by spraying, dripping, spraying and the like, and cooling is usually carried out using nitrogen, air and the like.

At this stage of obtaining BPA, especially at stage (a), by-products including 2,4'-bisphenol A (hereinafter referred to as "by-products upon receipt of BPA") are synthesized simultaneously with BPA. These by-products upon receipt of BPA are mainly contained in the mother liquor obtained in step (c), and they circulate through the step of obtaining BPA. For this reason, by-products upon receipt of BPA tend to accumulate in this circulation system. There is a tendency that when the accumulation of by-products upon receipt of the BPA occurs over a certain degree, the separation in step (c) will become insufficient and the by-products will begin to be partially present on the BPA side as well, which will result in a deterioration in the quality of the BPA product. For this reason, part or all of the mother liquor obtained in stage (c) is exposed to the mother liquor processing step in obtaining BPA (stage (g)), thereby isolating / removing by-products from the mother liquor in obtaining BPA. This mother liquor, in which the amount of by-products in the production of BPA was thus reduced, is used as a starting material in the production of BPA, whereby the quality of the BPA product can be ensured.

Stage (g) is a stage in which PL is recovered by distillation, or a stage in which the mother liquor is heated in the presence of a basic substance in order to decompose by-products in the production of BPA present in the mother liquor, and thereby obtain PL and PL derivatives, and these compounds, when using an acid catalyst or an alkaline catalyst, are subsequently reacted to produce BPA, which is recovered.

Specifically, as shown in FIG. 4, part or all of the mother liquor is first introduced into the PL 13 evaporator, and at the same time, a basic substance such as sodium hydroxide or potassium hydroxide is introduced. After that, the contents are heated to a temperature not lower than the boiling point of PL, to convert PL to steam, which is discharged through the top of the evaporator PL 13. The resulting evaporation residue, which contains BPA and by-products as the main components in the preparation of BPA are discharged through the lower part of the PL 13 evaporator and fed to residue processing reactor 14. The residue is heated to 180-300 ° C, thereby causing decomposition reactions of BPA and by-products upon receipt of BPA to produce decomposition products Comprising isopropenylphenol, which is an intermediate in the decomposition of BPA. These decomposition products are distilled off through the top of the column. On the other hand, the bottom residue obtained in this residue processing reactor 14, in the form of an spent solution containing a large amount of organic compounds, is fed to the waste solution processing step (not shown), such as, for example, disposal by burning.

PL and PL derivatives obtained as decomposition products of by-products upon receipt of BPA are distilled off through the upper part of residue processing reactor 14 and fed to regeneration reactor 15. If in this operation PL and PL derivatives are removed through the upper part of residue processing reactor 14, then then they will be mixed with PL discharged through the upper part of the PL 13 evaporator. As a result, the concentration of the PL derivatives decreases, and undesired side reactions can be suppressed.

Then, in the regeneration reactor, 15 PL and derivatives of PL, which are decomposition products of by-products upon receipt of BPA, are again reacted using an acid catalyst, thereby producing BPA and the like. This reaction product, together with unreacted PL, is mixed with PL used as starting material and fed to step (a). Since, as a result of step (c), BPA is recovered as such and PL is used as starting material, the efficiency of obtaining BPA can be improved.

Stage of obtaining RS

The stage of obtaining RS is the method shown in figure 5. Namely, the DPC and BPA obtained by the methods described above are used as starting materials and introduced into the mixing tank 21 together with the main catalyst (C2), such as, for example, an aqueous alkaline solution. The resulting mixture is fed to the polymerization reactor to carry out the polymerization step upon receipt of RS. No particular restrictions are imposed on the polymerization reactor until condensation polymerization can be carried out in it while the phenol formed as a by-product of the polymerization is distilled off. The polymerization reactor may be any type of reactor selected from a vertical reactor, a horizontal reactor and a column reactor.

The number of such polymerization reactors is not particularly limited. However, since the polymerization reaction is a condensation polymerization accompanied by the removal of phenol, it is preferable to use two or more than two polymerization reactors so that the polymerization conditions can be changed in accordance with the degree of polymerization. Figure 5 shows a group of polymerization reactors, which comprise three vertical polymerization reactors (first polymerization reactor 22, second polymerization reactor 23 and third polymerization reactor 24) and one horizontal polymerization reactor (fourth polymerization reactor 25) connected in series. The polymerization conditions in this case, for example, include 200-250 ° C and 50-200 torr for the first polymerization reactor 22, 230-280 ° C and 10-50 torr for the second polymerization reactor 23, 250-300 ° C and 0, 2-5 torr for the third polymerization reactor 24 and 260-320 ° C and 0.05-2 torr for the fourth polymerization 25. If these conditions of polymerization are used, then, as the polymerization proceeds, they will distill off the phenol by-product (here and hereinafter abbreviated as "s-PL"), whereby will get RS characterized by the desired degree of polymerization.

The steam-converted ingredients in the preparation of RS p, obtained in the polymerization step in the preparation of RS and including s-PL as the main component, are liquefied using heat exchangers 26 and 27 and a condenser 28 and fed into the reservoir for the recovered PL 29 in the preparation of RS. The discharged gas (D5), which remains unliquid, is diverted to the side of the vacuum device and fed to the processing stage (not shown).

The MS obtained in the polymerization step upon receipt of MS is fed to an extruder 32. In this extruder 32, the volatile compounds present are removed as discharged gas (D5) and acid I and various additives J are added to neutralize the catalyst and the like. The polymer is then subjected processing (not shown), such as, for example, granulation, to obtain PC as a product.

As stated above, the steam-converted ingredients upon receipt of MS p are liquefied and fed into the reservoir for recovered PL 29 upon receipt of MS. Despite the fact that the steam-converted ingredients in the production of RS p include s-PL as the main component, they also include DPC and BPA, which were used as starting materials, oligomers obtained by condensation polymerization between one or several DPC molecules and one or more BPA molecules, water derived from an alkaline catalyst, and the like. For this reason, the steam-converted ingredients in the preparation of PC p for s-PL recovery are subjected to the PL distillation step. Examples of this PL distillation step include a method in which distillation columns are used that are combined in a two-stage arrangement, such as that shown in FIG. Firstly, in the first distillation column PL 30, the ingredients having a boiling point lower than the boiling point of PL, which include water, are converted to steam and distilled off, and a low boiling point distillate in the production of PC (D6) containing as the main component water and containing PL are removed and recovered. After that, the resulting residue after distillation of the first stage q in the first distillation column PL 30 is fed to the second distillation column PL 31, where high-boiling compounds are cut off to extract s-PL as a result of distillation, and the residue after distillation PL (X2), which is high boiling compounds are recovered.

Processing by-product of phenol (s-PL) 1; s-PL water level

The water content of s-PL recovered in the distillation step of PL as a result of distillation is preferably 0.2 wt.% Or less, preferably 0.1 wt.% Or less, more preferably 0.05 wt.% Or less, even more preferably 0.01 wt.% or less. In the event that its content level exceeds 0.2 wt.%, Then this s-PL, being submitted to the stage of obtaining DPC or the stage of obtaining BPA, will lead to a decrease in catalytic activity at the stage of obtaining DPC and at the stage of obtaining BPA and will be prone to cause hydrolysis and the like to proceed at the DPC production step, which will be described later. For this reason, the use of such s-PL tends to result in a deterioration in production efficiency in the DPC preparation step and the BPA production step. On the other hand, the lower limit of the water content is 0 wt.%, Since the lower the water content, the better.

If an attempt is made to distill water from the steam-converted ingredients upon receipt of RS p in the first distillation column PL 30, then if distillation is carried out under normal conditions, a significant amount of PL will accompany the water, resulting in losses. This is because water and PL have the property of forming an azeotrope. Techniques for reducing these losses include distillation desorption, using vacuum conditions to eliminate azeotropy, and increasing the number of theoretical plates and reflux ratio. In any case, from an economic point of view, it is undesirable to carry out a complete separation. For this reason, it is possible to use the method in which the low-boiling distillate in the production of PC (D6), obtained by distillation of water together with part PL in the first distillation column PL 30 under normal distillation conditions, is fed to the DPC washing step in the DPC preparation step and / or to a water evolution step (step (b-2)) in the BPA production step.

The distillation conditions for the first distillation column PL 30 preferably include a pressure in the range of atmospheric pressure to a reduced pressure of several tens of torr and a top temperature of the column that will be not less than the boiling point of water at a given pressure and not more than the boiling point of phenol at a given pressure. The gas thus discharged through the top of this first distillation column PL 30 is a water / PL mixed gas, and it is preferable to bring the top temperature of the column to the boiling temperature of the mixed gas having the desired composition. If the top temperature of the column is lower than the boiling point of water, then the water content in the remainder of the first stage q will increase, which will result in the possibility that s-PL obtained in the second distillation column PL 31 may begin to be characterized by an increased level of water content that falls outside this range. On the other hand, if the top temperature of the column is higher than the boiling point PL, then the amount of s-PL contained in the low-boiling distillate upon receipt of RS (D6) will increase, which will result in the need to use a large amount of energy for it extraction. Thus, such a temperature is uneconomical.

Specifically, the level of PL in the gas discharged through the top of the first distillation column PL 30 is such that the concentration of PL is preferably 50 wt.% Or more, and particularly preferably 70 wt.% Or more and 99.8 wt. % or less.

The s-PL thus obtained is used as part of the starting material in the DPC preparation step or the BPA production step.

Specifically, in the DPC production step, s-PL is used in the reaction step in the production of DPC. When fed to the reaction step in the preparation of DPC s-PL can be used as part or all of the amount of PL used as starting material. Since in this case the water content in it is within the above range, the water contained in s-PL will have little effect on the reaction stage, and the efficiency of obtaining DPC can be ensured.

Further, in the BPA preparation step, s-PL is used in the reaction step in the production of BPA (step (a)). In the reaction step, upon receipt of BPA, s-PL can be used as part or all of the amount of PL used as starting material. Since in this case the level of water content in it is within the above range, the water contained in s-PL will have little effect on the stage of the synthesis reaction, and the efficiency of BPA production can be ensured.

Processing low boiling distillate upon receipt of RS (D6)

The low-boiling distillate (D6) converted to steam by distillation in the PL 30 first distillation column is returned to the DPC washing step in the DPC preparation step or to the water separation step (step (b-2)) in the BPA production step, as stated above, in as a result, it will be possible to extract PL in a low boiling point distillate to produce PC (D6).

Specifically, if the low boiling point distillate in the production of RS (D6) is returned to the washing stage of the DPC, for example, in the alkaline neutralization tank 4, in the stage of obtaining DPC, as shown in Fig. 1, then the PL contained in the low boiling point distillate in the production of RS (D6), extracted into the organic phase (liquid reaction mixture), recovered as a mixed gas (F) in a first distillation column to obtain DPC 6 in the next step, and finally used as starting material in the preparation of DPC.

On the other hand, if the low boiling point distillate in the production of PC (D6) is returned to the water washing step (step (b-2)) in the BPA production step, more specifically, for example, to the PL 12 recovery column, as shown in FIG. 2 or 3, then the PL contained in the low boiling point distillate upon receipt of PC (D6) is recovered as recovered liquid PL k through the bottom of the column and, in conclusion, is used as starting material in the production of BPA.

Processing by-product of phenol (s-PL) 2; processing of steam-converted ingredients upon receipt of RS at the polymerization stage upon receipt of RS

As shown in FIG. 5, steam-converted ingredients in the production of RS p, which include phenol obtained as a by-product in the polymerization step, are fluidized using heat exchangers 26 and 27 and a condenser 28 and fed to the recovered PL 29 reservoir for receiving RS . The discharged gas (D5) remaining unliquefied is fed to a processing step (not shown).

Incidentally, the mixtures of the steam-converted ingredients obtained respectively in apparatuses from the first polymerization reactor 22 to the third polymerization reactor 24 differ from each other in impurities different from the phenol by-product. Specifically, steam-converted ingredients discharged from the polymerization stage at an early stage, in addition to the phenol by-product, include impurities such as those having a boiling point lower than the boiling point of PL, a small amount of a carbonyl compound, diphenyl carbonate and things like that. These impurities are the starting material used in the DPC preparation step and the reaction products obtained in this step, and high boiling compounds, such as, for example, BPA, are not contained therein. Therefore, steam-converted ingredients that include these impurities can be used as part of the PL used in the DPC preparation step without purification or after purification to a low degree of purity.

On the other hand, steam-converted ingredients discharged from the polymerization stage in the late stage of the polymerization step for the production of MS, in addition to the by-product phenol, include impurities having a boiling point higher than the boiling point of PL, such as DPC, BPA and oligomers derived from DPC and BPA. They almost do not contain any impurities characterized by a boiling point lower than the boiling point PL. These impurities undergo hydrolysis at the stage of obtaining BPA and become the starting material and reaction products for this stage of preparation. Almost no alcohols and the like, which could cause a decrease in catalytic activity at the stage of obtaining BPA. For this reason, steam-converted ingredients that contain these impurities can be used as part of the PL used in the BPA preparation step without purification or after purification to a low degree of purity.

Consequently, the steam-converted ingredients released in the polymerization step upon receipt of the PC can be recovered in two batches, as shown in FIG. 6. Namely, the steam-converted ingredients produced in the first of two stages of the polymerization step, that is, the first steam-converted ingredients in the production of PC p1, extracted from the first polymerization reactor 22 or from the first polymerization reactor 22 and the second polymerization reactor 23 and containing phenol by-product can be fed to the first reservoir for the recovered PL 29a upon receipt of RS. In addition, the steam-converted ingredients produced in the second of two stages of the polymerization step, that is, the second steam-converted ingredients in the production of PC P2, extracted from the second polymerization reactor 23 and subsequent polymerization reactors or from the third polymerization reactor 24 and the subsequent polymerization reactor and containing phenol as a by-product, can be fed to a second reservoir for recovered PL upon receipt of PC.

Thus, the recovered first steam-converted ingredients upon receipt of PC p1 can be used as part of the PL used as starting material in the DPC production step without carrying out the PL distillation step shown in FIG. 5. On the other hand, the second steam-converted ingredients in the production of RS p2 can be used as part of the PL used as starting material in the BPA production step without carrying out the PL distillation step shown in FIG. 5.

It is preferable that the polymerization reactors (reactors) from which the first steam-converted ingredients are obtained in the production of PC p1, which contain the by-product phenol used in the DPC production step, i.e. the first polymerization reactor 22 or the first polymerization reactor 22 and the second polymerization reactor 23, would be equipped with a reflux apparatus 33a and 33b for liquefaction and boiling under conditions of phlegm formation of part of the converted into steam ingredients. Among the distillate ingredients selected from the first polymerization reactor 22 or from the first polymerization reactor 22 and the second polymerization reactor 23, ingredients that have a boiling point higher than the boiling point PL can be returned to the corresponding polymerization reactors using a reflux apparatus 33a and 33b. As a result, the fraction of ingredients with a boiling point higher than that of the boiling point PL can be further reduced in the obtained first steam-converted ingredients in the preparation of RS p1.

Incidentally, the steam-converted ingredients recovered from the second polymerization reactor 23 are supplied to any reservoir selected from the first reservoir for recovered PL 29a upon receipt of PC and the second reservoir for recovered PL 29b upon receipt of PC, as stated above. Regarding the selection of a reservoir for the recovered product, there can only be a pipeline for either of the two reservoirs for the recovered product. Alternatively, there may be pipelines respectively connected to two reservoirs for the recovered product, and valves 34a and 34b may be arranged in respective pipelines in order to suitably switch between pipelines, as shown in FIG. 6. The reasons for this are as follows. The amount of impurities other than the phenol by-product contained in the steam-converted ingredients recovered from the second polymerization reactor 23 is relatively small. Thus, these steam-converted ingredients can be used either as the first steam-converted ingredients in the preparation of RS p1, or as the second steam-converted ingredients in the production of RS p2.

If the steam-converted ingredients obtained as the distillate from the second polymerization reactor 23 are fed into the first tank for the recovered PL 29a upon receipt of the PC or in the second tank for the recovered PL 29b upon the receipt of the PC, then the amount of the supplied ingredients is adjusted according to the amounts converted into the steam of ingredients from other polymerization reactors, in particular with the amount of phenol by-product contained in these steam-converted ingredients and the amount of impurities containing those containing steam-transformed ingredients.

The amount of this phenol by-product in the phenol by-product contained in the steam-converted ingredients obtained in the polymerization step of the preparation of PC, which must be fed to the DPC production step and used as part of the PL starting material, i.e. the amount of the by-product of the the phenol contained in the first steam-converted ingredients upon receipt of RS p1 is preferably 50-95 wt.%, preferably 50-70 wt.%, based on the total amount by-product of phenol contained in the steam-converted ingredients obtained in the polymerization step in the preparation of MS, i.e., based on the total amount of phenol by-product contained in the first steam-converted ingredients in the preparation of MS p1 and contained in the second converted into steam ingredients upon receipt of RS P2.

On the other hand, the amount of the phenol by-product contained in the second steam-converted ingredients in the production of RS p2 is desirably 50-5 wt.%, Preferably 50-30 wt.%, Based on the total amount of phenol by-product contained in the steam-converted ingredients obtained in the polymerization step upon receipt of RS.

In the event that the amount of the phenol by-product contained in the first steam-converted ingredients upon receipt of RS p1 is less than 50 wt.%, Then impurities characterized by a boiling point lower than the boiling point of DPC, in particular alcohols and the like, will tend to be incorporated into the second steam-converted ingredients upon receipt of RS p2. The use of such steam-converted p2 ingredients without any processing as starting material in the production of BPA tends to result in a decrease in activity in the reaction. Thus, such amounts of a phenol by-product are undesirable. On the other hand, if its amount exceeds 95 wt.%, Then it will be possible that BPA and oligomers, which are characterized by a boiling point higher than the boiling point of DPC, can fall into the first ones converted to steam ingredients upon receipt of PC p1, causing clogging of the pipe upon receipt of DPC.

The content of high-boiling compounds characterized by a boiling point higher than the boiling point of DPC, such as BPA and oligomers derived from DPC and BPA, in the steam-converted ingredients used in the DPC production step, i.e. in the first steam-converted ingredients at obtaining RS p1, preferably is 1.0 wt.% or less, more preferably 0.1 wt.% or less. In the event that the level of their content exceeds 1.0 wt.%, Then it will be possible that clogging of the pipe may occur upon receipt of the DPC.

In addition, the low-boiling point content of the boiling point is lower than the boiling point of DPC, for example, the carbonyl compound and alcohol obtained as a by-product from the carbonyl compound, in the steam-converted ingredients used in the BPA preparation step, there are second steam-converted ingredients in the preparation of RS p2, preferably 100 ppm (wt.) or less, more preferably 50 ppm (wt.) or less. Incidentally, PL used as starting material in the BPA preparation step contains a by-product, phenol, contained in the first steam-converted ingredients in the preparation of RS p1 and in the second steam-converted ingredients in the preparation of RS p2, and further includes commercial phenol for deficiency coatings and PL circulating through the BPA production step. For this reason, the level of low boiling compounds in this PL used as starting material is lower than the level of low boiling compounds in the phenol by-product and, in general, is 20 ppm (wt.) Or less, preferably 5 ppm (wt.) or less. In the event that their content level is higher than 20 ppm (wt.), Then it will be possible that low boiling compounds can reduce catalytic activity in the production of BPA, which will lead to a decrease in productivity.

If the carbonyl compound is a dialkyl carbonate and / or alkyl aryl carbonate, then the alcohol obtained as a by-product from the carbonyl compound will be an alkyl alcohol derived from a dialkyl carbonate and / or alkyl aryl carbonate.

As a result of this extraction of the steam-converted ingredients in the preparation of RS p in two portions and the supply of two portions to the DPC preparation step and the BPA production step according to the types of impurities, the PL distillation step at the PC production step can be omitted and a contribution can be made to the improvement production efficiency.

Processing by-product of phenol (s-PL) 3; impurity classification for methods of using steam-converted ingredients in the preparation of RS p and commercial PL

Incidentally, in the event that the DPC production step and the BPA production step and the RS production step are of the same scale, then the amount of s-PL obtained in the PC production step shown in FIG. 5 will theoretically be approximately half of the total amount of PL used as starting material in the DPC production step and BPA production step, and the amount of PL used as starting material in the DPC production step will theoretically be the same amount as the quantity GUSTs PL, used as starting material in the production step of BPA. The disadvantage is covered using commercial PL (hereinafter referred to as "commercial PL"). For this reason, there are times when the problem arises of how to use s-PL and commercial PL.

In general, commercial PL contains some impurities, such as cresol and / or xylenol and hydroxyacetone, while the steam-converted ingredients from PC p, from which s-PL was not recovered as a result of distillation, are characterized by a reduced level impurities such as cresol and / or xylene and hydroxyacetone. For this reason, how to use s-PL can be determined based on the difference in the level of impurities such as cresol and / or xylenol and hydroxyacetone.

Specifically, it is preferred that the PL used as starting material in the DPC production step be phenol containing cresol and / or xylenol in an amount of 20-1000 ppm (wt.) (Hereinafter, referred to as "cresol-containing PL"), and so that the PL used as starting material in the BPA production step would be phenol containing cresol and / or xylenol in an amount of less than 20 ppm (wt.) (hereinafter, in this document denoted as "not containing cresol PL").

Examples of cresol-containing PL include commercial PL. This commercial PL in addition to cresol and xylenol contains staining impurities, such as hydroxyacetone, in the amount of several tens ppm (wt.).

As stated above, this cresol-containing PL can be used as such in the reaction step to prepare DPC. The amount of each of the impurities in a given cresol-containing PL, such as cresol, xylenol and staining impurities, for example hydroxyacetone, is within the range acceptable for the reaction step in the preparation of DPC. As a result of the processing in the first distillation column upon receipt of DPC 6, which will be described later, such impurities are distilled off as part of the mixed gas F or removed as a residue after distillation. Therefore, even if the DPC obtained using this cresol-containing PL is used at the stage of production of RS, this will not affect the quality of the obtained RS.

Examples of cresol-free PL include steam-converted ingredients in the preparation of PC p, from which s-PL was not recovered by distillation. The level of impurities that are catalytic poisons, for example hydroxyacetone, in the steam-converted ingredients in the production of RS p is preferably lower than 10 ppm, more preferably lower than 5 ppm, particularly preferably lower than 1 ppm . The level of their content, not less than 10 ppm, as a result will lead to a significant shortening of the life of the catalyst.

In addition to the impurities mentioned above, such as cresol, xylenol, and catalytic poison impurities, or staining impurities, such as hydroxyacetone, examples of the impurities contained in the vaporized ingredients in the preparation of PC p include DPC, BPA and oligomers resulting from a reaction between one or more DPC molecules and one or more BPA molecules.

The level of cresol and / or xylenol in the steam-converted ingredients upon receipt of RS p is preferably 20 ppm (wt.) Or less, more preferably 10 ppm (wt.) Or less. In the event that the level of their content is greater than 20 ppm (wt.), Then it will be possible that alkyl substituted derivatives of BPA can form, leading to a decrease in the purity of the BPA.

The steam-converted ingredients in the preparation of RS p contain water. The presence of water in the BPA production step causes a decrease in catalytic activity and thus leads to a decrease in the degree of conversion in the production of BPA. Therefore, it is necessary to carry out the stage of water removal. In order to achieve this, it is preferable to expose the steam-converted ingredients in the preparation of RS p to the water removal step, and then use the ingredients p in step (a) of the BPA preparation step.

As the stage of water removal, it is possible to use the stage of water allocation (stage (b-2)) as such. Namely, in FIG. 3, the steam-converted ingredients upon receipt of PC p are fed as starting material to a PL 12 recovery column to carry out the water removal step. A mixture of water / acetone AW, which in this operation during the distillation is converted to steam, is subjected to separate processing. On the other hand, the distillation residue in the PL 12 recovery column is fed to a high boiling point removal column, although this is not shown in FIGS. 2 and 3. After this, a high boiling point removal step can be performed to isolate boiling point ingredients. higher than the boiling point of PL, as a result of which high-boiling ingredients are isolated / removed as a bottom residue resulting from distillation, and PL is recovered as a distillate.

Thus, the recovered PL without any processing as being the starting material of the PL can be subjected to the reaction step upon receipt of the BPA (step (a)) in the step to obtain the BPA. Alternatively, the recovered PL can be temporarily stored in the reservoir for recovered PL 11 upon receipt of the BPA, and then subjected to step (c) and, if necessary, to the reaction step upon receipt of the BPA (step (a)) through the mother liquor processing step (step (g)), as shown in FIG. One of the reasons why the recovered PL is subjected to the BPA crystallization / recovery step (step (c)) is because pure PL is preferred as a cleaning liquid for the synthesized BPA. Another reason is that even if the recovered PL is subjected to the BPA crystallization / isolation step (step (c)), the impurities that fall into this step will be the 2,4'-BPA isomers and the like ( hereinafter referred to as “by-products upon receipt of BPA”) obtained in the reaction step upon receipt of BPA, and will not affect the synthesis reaction step. On the other hand, high boiling ingredients discharged from the high boiling point removal step are fed to the previously described mother liquor processing step (g), in which effective ingredients can be recovered.

As a result of such feeds of steam-converted ingredients in the preparation of RS p to the BPA production step and the use of commercial PL in the DPC production step, the negative influence of the impurities present can be reduced, and the PL distillation step in the PC production step can be omitted. Thus, it is possible to contribute to improving the efficiency of obtaining.

The connection of the stages of obtaining; availability of storage stages

1. The stage of obtaining RS

At the stage of production of MS, the storage stage upon receipt of MS (the stage of first storage upon receipt of MS or the stage of second storage upon receipt of MS), intended for storing liquid obtained by liquefying the steam-converted ingredients upon receipt of MS, which must be subjected to the distillation stage PL, and / or for storing s-PL recovered in the PL distillation step, can be located before and / or after the PL distillation step, as shown in FIG. 7. The presence of the storage stage upon receipt of MS has the following effect. Even if the polymerization stage of the preparation of RS is temporarily stopped or carried out periodically, the steam-converted ingredients of the preparation of RS p or s-PL stored at this storage stage during the preparation of RS can be continuously fed as the starting material PL to the next stage, then there is a PL distillation step or a reaction step in the preparation of DPC or a reaction step in the production of BPA, whereby the subsequent step can be carried out continuously.

The capacity of the storage tank when receiving RS, used at the storage stage when receiving RS, can be determined taking into account the operating time and idle time for the polymerization stage when receiving RS. Specifically, the tank is preferably characterized by a capacity satisfying the requirement presented in the following expression (1):

In the expression (1), Vc denotes the capacity (m ³ ) of the storage tank for the production of MS, and Fc denotes the flow rate (m ³ / h) of liquefied, vaporized ingredients in the production of MS or a phenol by-product.

If the value of Vc / Fc is less than 10, then there will be cases when it will be difficult to continuously feed to the next step the steam-converted ingredients upon receipt of PC p or s-PL. In addition, it will be difficult to regulate those fluctuations in the composition of the converted into steam ingredients upon receipt of RS p, which accompany changes in the brand of RS product. On the other hand, the Vc / Fc value may be greater than 100. However, excessively large tank capacities are undesirable since the need to store such a large amount is small in terms of production efficiency, which as a result will result in waste rather than improved production efficiency, and since an excessively long holding time is undesirable from the point of view of heat resistance.

By the way, this storage tank when receiving RS can only be located at one stage, selected from the first storage stage when receiving RS and the second storage stage when receiving RS, or it can be located at each of two stages. At one storage stage when receiving RS, one storage tank for receiving RS of the type described above can be located, or two or more than two storage tanks for receiving RS can be arranged sequentially or in parallel. In the event that two or more than two tanks Vc are located in the expression (1), it will mean the total capacity of the data of the available tanks.

2. The stage of obtaining DPC

In the DPC production step, the DPC storage storage step for storing the DPC obtained from the distillation step in the production of the DPC can be positioned after the DPC production distillation step, as shown in FIG. 7. The presence of this storage step upon receipt of the DPC has the following effect. Even if the carrying out of the DPC production step is temporarily stopped or carried out periodically, the DPC stored at this storage step upon receipt of the DPC can be continuously fed as a DPC starting material to the next step, that is, the PC production step, whereby the PC can be produced continuously.

The capacity of the storage tank when receiving the DPC used in the storage stage when receiving the DPC can be determined taking into account the operating time and idle time for the stage of receiving the DPC. Specifically, the reservoir is preferably characterized by a capacity satisfying the requirement presented in the following expression (2):

In expression (2), Vd indicates the capacity (m ³ ) of the storage tank upon receipt of the DPC, and Fd means the flow rate (m ³ / h) of diphenyl carbonate.

If the value of Vd / Fd is less than 10, then there will be cases when it will be difficult to produce a continuous supply of DPC to the next stage. On the other hand, the Vd / Fd value may be greater than 100. However, excessively large tank capacities are undesirable since the need to store such a large amount is small in terms of production efficiency, which as a result will result in waste rather than improved production efficiency, and since excessively large tank capacities are also undesirable in terms of heat resistance.

Incidentally, one storage tank may be disposed upon receipt of a DPC of the type described above, or two or more than two storage reservoirs may be arranged sequentially or in parallel upon receipt of a DPC. In the event that two or more than two tanks are located, Vd in expression (2) will denote the total capacity of these tanks.

3. The stage of obtaining BPA

In the BPA preparation step, the storage step in the production of the BPA for storing a mixture of bisphenol A (BPA) and phenol (PL) is located after the PL removal step (step (e)), as shown in FIG. 7, or between the crystallization step / isolation of BPA (step (c)) and the step of removing PL (step (e)), despite the fact that the second case is not shown in Fig.7.

The presence of this storage step upon receipt of the BPA has the following effect. Even if any one stage at the stage of obtaining BPA is temporarily stopped, and the stages preceding the stopped stage are carried out periodically, the mixture stored at this stage of storage upon receipt of BPA can be fed to the stage of obtaining RS, so that RS can be obtained continuously.

In particular, the crystallization / separation step of the BPA (step (c)) tends to lead to the formation of solid deposits on those parts of the used crystallizer, including the crystallization tank and heat exchanger, which come into contact with the liquid. Thus, it is necessary to stop carrying out this stage and carry out cleaning at intervals of several months. For this reason, steps ranging from a reaction step upon receipt of BPA (step (a)) to a crystallization / isolation step of BPA (step (c)) tend to be carried out periodically. Therefore, the location of the storage step upon receipt of the BPA after the PL removal step (step (e)) or between the crystallization / separation step of the BPA (step (c)) and the PL removal step (step (e)), despite the fact that the second the case in the figure is not shown, makes it possible to continuously conduct the stage of obtaining MS, even if the stages concluded ranging from the reaction stage upon receipt of BPA (stage (a)) to the crystallization / isolation of BPA (stage (c)), and carried out periodically.

Examples of the form of the mixture intended for storage during the storage step upon receipt of BPA include crystals of the adduct BPA and PL, a suspension containing crystals of the adduct BPA and PL, a liquid mixture of BPA and PL, and the like.

The BPA / PL mixture is generally characterized by a composition in which the BPA content is in the range of 45-70 wt.%, And the PL content is in the range of 55-30 wt.% For this reason, if the temperature during storage is 0 -95 ° C, then the adduct will be crystalline. In the event that the proportion of phenol in the mixture is high, PL, which will not be in the form of an adduct with BPA, will go into the molten state when the storage temperature rises to 40 ° C or more. In this case, the mixture is a suspension or solution. In addition, if the storage temperature exceeds 95 ° C, then the adduct will melt and, thus, will go into a melt state.

The storage temperature is preferably in the range of 45-150 ° C. It is preferred that the BPA / PL mixture be in suspension or solution. In order to prevent decomposition or staining of the BPA, it is preferable to keep the mixture at the lowest possible temperature. Under these conditions, it is possible to inhibit the formation of 4-isopropenylphenol, which appears to be a staining substance resulting from the decomposition of BPA.

It is also important that the atmosphere in the storage tank be an inert gas atmosphere, such as nitrogen gas, to prevent the formation of air inclusions. Although conventional austenitic stainless steel or ferritic stainless steel can be used as the material for the storage tank, it is preferable to use material reduced by dissolving the iron, which causes a weakening of the color tone. In particular, a steel material having a chromium content of 16% or more and a carbon content of 0.03% or more is preferred. For example, using SUS304 rather than SUS316 is preferred and using SUS316 or SUS304 rather than SUS316L or SUS304L. It goes without saying that SUS309S and SUS310S, which are characterized by a higher chromium content, are more preferred.

The capacity of the storage tank for the BPA / PL mixture can be determined taking into account the operating time and downtime for the BPA production step. Specifically, the tank capacity preferably satisfies the requirement presented in the following expression (3):

In expression (3), Vb denotes the capacity (m ³ ) of the storage tank upon receipt of BPA, and Fb denotes the flow rate (m ³ / h) of bisphenol A supplied to the polymerization step upon receipt of RS.

If the value of Vb / Fb is less than 10, then there will be cases when it will be difficult to carry out the polymerization stage upon receipt of RS. On the other hand, the Vb / Fb value may be greater than 1000. However, excessively large tank capacities are undesirable since the need to store such a large amount is small in terms of production efficiency, which as a result will result in waste rather than improved production efficiency, and since long-term aging is also undesirable in terms of quality.

Incidentally, one storage tank of this type can be arranged, or two or more than two storage tanks can be arranged sequentially or in parallel. In the event that two or more than two tanks are located, Vb in expression (3) will denote the total capacity of these tanks.

Since the adduct, which is in the form shown above, is stored during the storage of the BPA during the storage step, the decomposition reaction of the BPA tends to occur when the pH value is shifted to the acid side or the alkaline side. In order to prevent this, in the storage tank when receiving BPA, located between the crystallization / isolation of BPA (stage (c)) and the polymerization stage when receiving RS, or at the stage preceding these stages, it is preferable to organize the neutralization stage at getting BPA (not shown). In the neutralization step, upon receipt of the BPA, the acid ingredient or the main ingredient present in the mixture can be neutralized, as a result of which the decomposition of the BPA in the mixture can be inhibited.

Waste solution recycling

(Processing of the residue after distillation PL (X2))

The distillation residue PL (X2) contains PL, DPC, BPA, oligomers obtained by condensation polymerization between one or more DPC molecules and one or more BPA molecules, and the like. These include large quantities of PL, BPA, and DPC. Therefore, in order to effectively use these effective ingredients, the distillation residue PL (X2) is fed to the distillation step or the extraction / distillation step in the DPC preparation step or to the mother liquor processing step (step (g)) in the BPA production step, such as shown in FIG.

If the DPC production step does not include the extraction / distillation step, and the residue after distillation PL (X2) is fed to the distillation step in the DPC production step, then the residue after distillation PL (X2) will be specially fed to the first distillation column upon receipt of DPC 6 as shown in FIG. As a result, the distillation residue PL (X2) is subjected to distillation in a first distillation column to obtain DPC 6 and a second distillation column to obtain DPC 7, and PL and DPC are recovered. Among them, PL is recovered as one mixed gas component (F) in the first distillation column upon receipt of DPC 6, while DPC is recovered in the second distillation column upon receipt of DPC 7.

If the DPC production step will include the extraction / distillation step, and the PL distillation residue (X2) will be fed to the DPC extraction / distillation step, then the PL X2 distillation residue will be specially fed to the extraction / distillation column upon receipt of DPC 8 as shown in FIG. As a result, the distillation residue PL (X2) will be distilled in the recovery / distillation column to obtain DPC 8, and PL and DPC will be removed and fed to mixing vessel 3. Among them, PL is recovered as one mixed gas component (F) in the first distillation column upon receipt of DPC 6, while the DPC is recovered in the second distillation column upon receipt of DPC 7.

In addition, if the distillation residue PL (X2) will be fed to the mother liquor processing step (step (g)) in the BPA production step, then the distillation residue PL (X2) will be specially fed to residue processing reactor 14, as demonstrated figure 4. As a result, PL as such is distilled off, while other ingredients decompose and again form BPA and other compounds in the regeneration reactor 15. These compounds are fed to a BPA production reactor (not shown) in the BPA production step. Thus, PL is used as starting material, and BPA moves in conjunction with synthesized BPA.

(Processing of the residue after distillation (X1) or the residue after extraction / distillation (X1 '))

In the DPC production step, the distillation residue (X1) obtained when the DPC production step does not include the recovery / distillation step, or the residue after extraction / distillation (X1 ') obtained when the DPC production step includes the recovery / distillation step , will contain impurities in the form of DPC derivatives, such as DPC, methyl substituted DPC derivatives and brominated substituted DPC derivatives, and other impurities. If the residue after distillation, PL (X2) is introduced into the distillation stage or the extraction / distillation stage, then the residue (X1) or (X1 ') will additionally contain BPA, oligomers obtained as a result of the passage of condensation polymerization between one or more DPC molecules and one or several molecules of BPA, and other impurities. Among these impurities, BPA and DPC are contained in large quantities. Therefore, in order to effectively use these effective ingredients, the residue after distillation (X1) or the residue after extraction / distillation (X1 ') is fed to the mother liquor processing step (step (g)) in the BPA production step.

In this case, the residue after distillation (X1) or the residue after extraction / distillation (X1 ') is specially fed into the processing reactor of residue 14, as shown in FIG. 4. As a result, the ingredients decompose, and part of the decomposition products in the regeneration reactor 15 is converted back to BPA. The resulting BPA and phenol are fed to a BPA production reactor (not shown) in the BPA production step.

(The residue after distillation PL (X2) and the residue after distillation (X1) or the residue after extraction / distillation (X1 '))

Examples of methods for processing the residue after distillation PL (X2), the residue after distillation (X1) and the residue after extraction / distillation (X1 ') include those described above. Among them, a method is preferred in which the distillation residue PL (X2) is fed to the distillation step upon receipt of DPC or to the extraction / distillation step upon receipt of DPC, and after that the distillation residue upon receipt of DPC (X1) resulting from stage distillation upon receipt of DPC, or the residue after extraction / distillation upon receipt of DPC (X1 ') is fed to the stage of processing the mother liquor upon receipt of BPA (stage (g)).

As a result of such processing of the residues, the spent solutions discharged from the DPC production step, the BPA production step and the RS production step are collected together in one spent solution (D7) resulting from the mother liquor processing step (stage (g)) at the production stage bisphenol A (BPA). Thus, the spent solutions, respectively obtained as a result of three stages and containing large quantities of organic compounds, can be collected together, and the amount of all spent solutions can be reduced. Therefore, the stage of processing the spent solution (not shown) is carried out efficiently, and the load for the stage can be reduced.

Vacuum device

A distillation apparatus, such as distillation columns, and a polymerization apparatus at the distillation stage in the preparation of DPC, polymerization stage in the production of PC and distillation stage PL are equipped with a condenser for condensing the distillate ingredients, a vacuum device to reduce the pressure in the system and a vacuum pipe that connects the condenser and the vacuum device . With respect to the distillation apparatus described as an example, explanations are given below. As shown in FIG. 9, the distillation apparatus 41 is provided with a condenser 42 for condensing the distillate compounds, such as DPC and PL, a vacuum device 43 to reduce the pressure in the system and a vacuum pipe 44 that connects the condenser 42 to the vacuum device 43.

This distillation apparatus 41 often includes a boiling portion under reflux conditions. The devices that make up this part for boiling under reflux conditions include a condenser 42 for condensing the distillate compounds, a condensate tank 45 for collecting a portion of the condensate, a liquid supply pump 46 for returning condensate in the condensate tank 45 to the distillation apparatus 41, and a reflux line 47 which connects the fluid supply pump 46 to the distillation apparatus 41. Hereinafter, this boiling portion under reflux conditions is referred to as a “reflux apparatus”.

The vacuum device 43 is a device that is used to suck and discharge the gas present in the distillation apparatus 41 and the reflux apparatus, and thus create a vacuum state in the distillation apparatus 41. Examples of this vacuum device 43 include vacuum pumps.

The vacuum pipe 44 connected to this vacuum device 43 is tilted downward from the side of the condenser 42 to the side of the vacuum device 43. It is desirable that in the horizontal parts of the vacuum pipe 44, the parts having this tilt are as long as possible. No particular restrictions are imposed on the degree of inclination until the downward inclination angle formed with the horizontal direction is greater than 0 ° and not less than 90 °. However, the degree of downward inclination in the desired embodiment is 1 cm or more, in a more desirable embodiment, is in the range from 5 cm to 1 m per 2 m horizontally in the direction of the vacuum device. More preferably, the horizontal parts having a slope would not have a part that is fully horizontal or rises upward. Even more desirably, the tilt is constant throughout the vacuum conduit 44. The term "horizontal parts" refers to parts that are in a horizontal state and parts that are in a state of slight tilt with respect to the horizontal state. The term "fully horizontal parts" refers to parts perpendicular to the vertical direction.

The inclined part may include fully horizontal parts or rising parts. However, the total height of the rising parts is preferably 1 m or less, more preferably 50 cm or less, even more preferably 10 cm or less. Most preferably, the inclined portion would not include such portions. In the event that the combined height of the rising parts exceeds 1 m, it will be possible that when the distillate remains in the rising parts, this may result in excessively large pressure losses and make it impossible to carry out sufficient evacuation. The term "rising parts" means parts that are inclined upward from the side of the capacitor 42 to the side of the vacuum device 43 opposite to the inclination described above. In such rising parts, the distillate tends to remain in the form of a liquid or solid phase. If the distillate remains, this will result in a loss of pressure. An excessively large amount of distillate remaining can clog the pipe itself. Therefore, it is desirable that the vacuum pipe 44 would not include rising parts. For this reason, it is more preferable that the vacuum pipe be inclined only downward from the side of the capacitor 42 to the side of the vacuum device 43.

Capacitor 42 condenses PL, DPC, and the like. The condensed distillate is discharged from the system or fed to the condensate tank 45 in a reflux apparatus in preparation with supply to the distillation apparatus 41.

The pressure in the distillation column 41 is preferably a reduced pressure, more preferably 1-200 torr, particularly preferably 5-100 torr. If the distillation column 41 has such an internal pressure, then the pressure in the evacuated vacuum conduit 44 through which the gas is evacuated in the distillation column 41 will preferably be close to or lower than the pressure in the distillation column 41, and more preferably 1-100 Torr

In addition, the pipeline extending from the top of the distillation column 41 to the condenser 42, in a desirable embodiment, has a design that satisfies the following requirements. The inner diameter of the pipeline is desirably such that the actual linear gas velocity is in the range of 0.01-20 m / s. The shorter the length of the pipeline extending from the top of the distillation column 41 to the condenser 42, the better. Its length in the desired embodiment is 10 m or less, in the more desirable embodiment 0 m. In addition, the smaller the number of bent parts in the pipeline, the better. Their number in the desired embodiment is 5 or less. Given these requirements, it is most desirable that the condenser 42 be placed on top of the distillation column 41 in the form of a capacitor for the upper part of the column. When these requirements are met, a more stable vacuum state is obtained in the distillation column 41 obtained using a vacuum device 43.

It is desirable that the supply of gas consisting of PL and DPC converted to steam be carried out, creating a downward flow through the capacitor 42. It is also desirable that the inner part and the part with the outlet at the capacitor 42 have a large diameter, which will result in low linear gas velocity. In the event that the linear gas velocity is high, this will cause a pressure drop, and it will be possible that the vacuum state cannot be maintained in the distillation apparatus 41.

It is desirable that the mist eliminator 48 for collecting the mist be positioned between the condenser 42 and the vacuum pipe 44. This is intended as much as possible to prevent PL or DPC from getting into the vacuum pipe 44 and stagnating or solidifying it there.

The vacuum pipe 44 in a desirable embodiment is a device designed to heat and maintain its internal space at a temperature not lower than the melting point of the distillate. Examples of this device include devices in which the vacuum pipe 44 has a two-pipe design or a design with steam or electric heating. In the event that the distillate will consist of two or more than two ingredients, then it is desirable that the temperature at which it is necessary to withstand the interior of the pipe 44 is not lower than the melting point of a compound characterized by a melting point, most high in the number of these compounds. Although the interior of the vacuum conduit 44 is in a vacuum state, the term “melting point” as used herein means the melting point in a vacuum state. If the internal space of the vacuum pipe 44 is maintained at a temperature not lower than the melting point of the distillate, then PL or DPC, which were not condensed in the condenser 42 and entered the vacuum pipe 44, will remain in a liquid or gaseous state without solidification, as a result, the likelihood that the interior of the vacuum conduit 44 may be clogged can be further reduced. Therefore, from the point of view of carrying out the stage, it is desirable to maintain the interior of the vacuum pipe 44 at a temperature of not less than 80 ° C, which is the melting point of the DPC, and not higher than the top temperature of the distillation apparatus 41.

Preferably, the vacuum pipe 44 would be provided with at least one drainage hole 49 facing down. This is due to the need that the distillate, which has undergone liquefaction in the vacuum pipe 44 or has become dew, needs to be exhausted without stagnation in the vacuum pipe 44. At least one of such drainage holes 49 is preferably located close to that part of the vacuum pipe 44, which is connected to the vacuum device 43. The reason for this is as follows. Since the vacuum pipe 44 is inclined, the discharge of the distillate through an opening that is not located as close as possible to the lower part of the inclined pipe results in the possibility that the distillate may remain in that part that is outside the scope of the opening. This release of fluid can be carried out not during evacuation using a vacuum device 43, but after the entire apparatus has been stopped. In the event that the length of the vacuum pipe 44 exceeds 3 m, it would be desirable to arrange the drainage hole 49 also in the interior of the vacuum pipe 44, since this will make it easier to prevent stagnation of the liquid.

In addition, it is desirable that the vacuum pipe 44 — in that part which is located on the side of the condenser 42 — be provided with a feed opening 50 through which heated fluid could be supplied. The closer the position of this supply opening 50 is to the capacitor 42, the more this will be desirable. However, in the event that a mist eliminator 48 is present in the gap between the vacuum pipe 44 and the condenser 42, it is desirable that the position of the supply opening 50 is not located in the gap between the mist eliminator 48 and the condenser 42, but as close as possible to that part of the vacuum pipe 44 which will be connected to the mist eliminator 48. As a result of the supply opening 50, heated fluid can be introduced through this opening and discharged through the drainage opening 49, whereby to clean the vacuum pipe 44. Therefore, it is desirable that a portion in the range from the supply hole 50 to the drain hole 49 should occupy the longest possible portion of the vacuum pipe 44. Due to the inclination, it will be more efficient to supply from the side corresponding to a higher potential energy . Therefore, it is desirable that the supply hole 50 on the vacuum pipe 44 would open upward.

A heated fluid is a substance that is fluid at a temperature in the interior of the vacuum conduit 44 and may be either liquid or gas. Examples of the heated fluid include water vapor, PL, nitrogen, and the like. More preferably, the heated fluid would be water vapor or PL vapor. The use of PL vapor is even more desirable since even if the DPC solidifies in the vacuum conduit 44, this solid phase can be dissolved. The heated fluid may consist of one of these components or a mixture of two or more than two of these components. However, it is desirable that the heated fluid is one that is unlikely to react with the material of the vacuum pipe 44, DPC and the like under conditions of temperature and pressure in the vacuum pipe 44. More preferably, it would be a medium that absolutely would not have reacted.

Preferably, the vacuum pipe 44 would be provided with valves 51 and 52 located in its parts connected to the capacitor 42, the vacuum device 43, the mist eliminator 48 and the like. This is because when cleaning the vacuum pipe 44 under the influence of the heated fluid, dosing using valves can prevent the leakage of the heated fluid from the vacuum pipe 44.

It is also desirable that the vacuum conduit 44 be provided with a freezing capacitor (not shown). More preferably, two or more than two freezing capacitors would be arranged in parallel, which would enable switching. The presence of freezing capacitors (condenser) is desirable, since it would be possible to force-harden and collect the distillate ingredients that cannot be trapped by the condenser 42, and to suppress the formation of clogging in those parts of the vacuum pipe 44 that are located according to the technological scheme after the freezing capacitors (condenser) or an increase in pressure loss.

In the event that low boiling compounds such as PL are distilled from the DPC, then in order to fluidize the gas discharged as distillate from the distillation apparatus 41, it will also be effective to use two or more than two capacitors 42 connected in series. In this case, the temperatures of the capacitors 42 are preferably controlled so that as the distance from the distillation column 41 increases, the temperature gradually decreases. In particular, in the first condenser 42, adjustment is carried out so as to have a temperature in the range of 80-150 ° C. in order to confidently condense high-boiling ingredients, such as DPC, and for the resulting condensate to circulate with the supply to the distillation apparatus 41. After that, non-condensed gas that has not been liquefied in the first condenser 42 is almost completely liquefied in the second and subsequent condensers 42, where the temperature is 0-80 ° C as a result of the adjustment. The condensate thus obtained as a result of liquefaction is partially subjected to boiling under reflux conditions and fed to the distillation apparatus 41 as needed, and the remaining or all of the condensate is discharged as a distillate. The presence of two or more than two capacitors 42 allows you to achieve the following advantages. Even if a large amount of DPC is discharged from the distillation column 41, the DPC will neither solidify nor cause clogging in the capacitors 42, so that the apparatus can be operated continuously and the distillation can be stably carried out for a long time. The solidification temperature of the DPC is 80 ° C, which exceeds the solidification temperature (40 ° C) PL. For this reason, if a large amount of DPC will be present in a capacitor 42 operating under temperature conditions suitable for condensing only one conventional low boiling compound, such as PL, then it will be possible for the DPC to solidify inside the capacitor 42. Therefore, it is effective in preventing hardening and withstanding the degree of evacuation in the distillation apparatus 41 by the method in which two or more than two capacitors 42 are arranged and used so that the DPC, which is a high melting compound, is forced to be condensed / removed before how the non-condensed gas will be condensed. Furthermore, if, in addition to PL, a large number of compounds having a boiling point lower than the boiling point of PL will be present in the distilled low boiling compounds, then the use of such capacitors 42 with a multi-stage configuration will be desirable.

Next, with reference to FIG. 9, explanations will be given regarding the reflux apparatus described above. As a result of using this reflux apparatus, it is possible to increase the separation efficiency as a result of distillation while suppressing the conversion of high boiling ingredients into steam.

The horizontal portion of the boiling pipe under reflux conditions 47, designed to boil condensate under reflux conditions in the condensate tank and fed to the distillation apparatus 41 when using a pump for supplying liquid 46, is preferably inclined downward from the side of the distillation apparatus 41 to the pump side for fluid supply 46. In a desirable embodiment, the horizontal portion having a slope does not include any portion that is fully horizontal or rises would be up. More preferably, the slope would be constant. In this case, the degree of downward inclination in the desired embodiment is 1 cm or more, in a more desirable embodiment, is in the range from 5 cm to 1 m per 2 m horizontally in the direction of the fluid pump 46. If there are fully horizontal parts or rising parts then it will be necessary that the height difference resulting from the inclination is greater than the total height difference for the lifting parts, and the total height of the lifting parts in the desired embodiment would be 1 m or less, more preferably 10 cm or less. The term "rising parts" means parts that are inclined upward from the side of the distillation apparatus 41 to the side of the liquid supply pump 46 opposite to the inclination described above.

That part of the boiling pipe under reflux 47, which is located between the horizontal part, characterized by the presence of a slope, and the pump for supplying liquid 46, may include a part that is vertical or almost vertically inclined, as shown in Fig.9, despite the fact that it depends on the position of the pump for supplying liquid 46. In this case, the drainage holes 53 and 54 can be located in those parts of the pipeline that are in the vicinity of the hole for suction and outlet, respectively, at the pump for supplying liquid 46 in order to release fluid stagnant before and after the pump for supplying liquid 46.

The reflux pipeline 47 is desirably characterized by the presence of a device for heating and maintaining its internal space at a temperature no lower than the melting point of the distillate. In the event that the distillate will consist of two or more than two ingredients, then heating and maintaining the internal space of the pipe 47 at a temperature not lower than the melting point of the compound characterized by the melting point, the highest among these compounds, will be desirable. If the reflux line is maintained at a temperature not lower than the melting point of the distillate, then the distillate will remain in a liquid or gaseous state without solidification, as a result of which the likelihood that the inner space may be clogged with distillate can be further reduced. Examples of a device for such heating / temperature control include devices in which the pipeline has a two-pipe structure or a design with steam or electric heating.

It is desirable that this reflux line 47 would have a supply opening 55 located on that part that would be close to the distillation column 41. In the event that the operation of the entire apparatus is stopped, then the heated fluid will be introduced through this supply opening 55 and discharged through the drain hole 54, so that it will be possible to clean the reflux pipe 47. In this case, it is desirable that the valve 56 be located in the gap between the reflux pipe 47 and by distillation apparatus 41 in order to prevent the flow of heated fluid into distillation apparatus 41.

Incidentally, a distillation apparatus for separating PL or DPC as a distillate, such as those described above, can be used to extract PL or DPC, for example, at the stage of distillation in the preparation of DPC, in which impurities including PL are removed from DPC for in order to extract purified DPC, or at the polymerization stage when producing MS, or at the stage of distillation of PL at the stage of obtaining MS, in which MS is obtained by polymerization due to the reaction between DPC and BPA in vacuum while removing PL obtained as a by-product (s-PL). The distillation apparatus is also suitable for use in stages in which PL or DPC are likewise isolated as a distillate.

Furthermore, although a reflux apparatus, PL or DPC, such as described above, can be used in the step described above as an example, in which PL and DPCs discharged as distillate from distillation apparatus 41 are returned to the distillation apparatus 41 to inhibit the vaporization of the high boiling ingredients contained in the PL and DPC feeds, and thus to increase the separation efficiency as a result of distillation, it is also suitable for use in stages where refluxing Ovia phlegm formation is just as necessary. Incidentally, the high boiling ingredients can be separately released through the bottom of the distillation apparatus 41.

In the event that these devices will be used to obtain DPC, then in a desirable embodiment, the reflux pipeline 47 - in that part which is different from the horizontal part having a slope - will have an outlet 57 for discharging from the DPC system.

As a result of using the above apparatuses respectively, at these stages, clogging of the pipe, if this happens, can be easily eliminated by using a cleaning method in which heated fluid is supplied through the supply openings 50 and 55 located on the corresponding apparatus.

Examples

Example 1

The invention will now be described in more detail in connection with the processing of s-PL.

Getting dehydrated s-PL

Stage polymerization upon receipt of RS

In an atmosphere of gaseous nitrogen, BPA (manufactured by Mitsubishi Chemical Corp .; BPA obtained in Reference Example 2 below), supplied at a rate of 34.3 kg / hr, was melt-mixed at 130 ° C. with DPC (produced in Mitsubishi Chemical Corp .; DPC obtained in Reference Example 1 below) supplied at a flow rate of 33.5 kg / h. This mixture was continuously fed through a feed pipe, heated to 130 ° C, into the first vertical stirred polymerization reactor, in which, as a result of adjustment, the temperature was kept at 210 ° C in a nitrogen atmosphere at normal pressure. The liquid level was kept constant by adjusting the degree of openness of the valve located on the polymer discharge line connected to the lower part of the tank, so as to result in an average residence time of 60 minutes. In addition, simultaneously with the initiation of the feed of the mixture of starting materials as a catalyst, cesium carbonate in the form of an aqueous solution began to be continuously fed at a flow rate of 0.5 · 10 ^-6 mol per one mol of BPA. After that, the liquid polymerization reaction mixture discharged from the lower part of the vessel was continuously fed sequentially to the second, third and fourth vertical polymerization reactors and the fifth horizontal polymerizer. During the reaction, the liquid level in each tank was adjusted so as to obtain an average residence time of 60 minutes, and at the same time, the PL obtained as a by-product was distilled off. Each of the gases obtained by evaporation and discharged, respectively, from tanks in the range from the first to the third polymerization reactors was condensed and liquefied using a multi-stage condenser, and part of the condensate was boiled under reflux conditions and fed to the polymerization reactor, and the remainder was recovered and stored in the tank for s-PL. On the other hand, each of the gases obtained by evaporation and discharged from the fourth and fifth polymerizers was cured using one of two freezing condensers arranged in parallel. The resulting solid phase was melted by switching to another freezing capacitor, recovered and stored in an s-PL tank.

The conditions for each polymerization reactor were as follows: a first polymerization reactor (210 ° C, 100 torr), a second polymerization reactor (240 ° C, 15 torr), a third polymerization reactor (260 ° C, 0.5 torr) and a fourth reactor polymerization (270 ° C, 0.5 torr). In addition, the production rate for polycarbonate was 38.3 kg / h. The system functioned for 400 hours.

The resulting polymer in the molten state was introduced into a twin-screw extruder (manufactured by Kobe Steel, Ltd .; worm diameter 0.046 m; L / D = 40.2) and 5 ppm butyl p-toluenesulfonate was continuously added thereto. when calculating the amount of polycarbonate. Butyl p-toluenesulfonate was in the form of a masterbatch obtained by dispersing the mother liquor in polycarbonate flakes using a mixer, and it was fed to the extruder in a nitrogen atmosphere using a mass feeder. The polymer was granulated. The resulting polycarbonate was characterized by a viscosity average molecular weight (Mv) of 21,000 and an initial color tone (YI) of 1.7.

Medium viscosity molecular weight (Mv) measurement

To measure the specific viscosity (ηsp) with a Ubellode viscometer at a temperature of 20 ° C, a solution in methylene chloride with a concentration of PC (C) of 0.6 g / dl was used, and the molecular weight was calculated from the viscosity using the following two equations:

ηsp / С = [η] (1 + 0.28ηsp)

[η] = 1.23 · 10 ^-4 (Mv) ^0.83

Initial Hue Measurement (YI)

RS was dried at 120 ° C for 6 hours in a nitrogen atmosphere, and then using a J-100 injection machine manufactured by The Japan Steel Works, Ltd., a piece having 3 mm thick. This piece was examined using an SC-1 instrument manufactured by Suga Test Instruments Co., Ltd. to obtain a YI value (the higher the YI value, the more PC will be colored).

S-PL purification step

We analyzed s-PL recovered in the polymerization step at a capacity of 30.2 kg / h. As a result, 5.0 wt.% DPC, 0.5 wt.% BPA, 0.3 wt.% Oligomers and 0.3 wt.% Water were found.

This s-PL was continuously purified using the following two distillation columns. The first distillation column PL was operated at 200 torr and reflux number 2, whereby the water present was distilled off together with part PL. VAT residue was fed to the second distillation column PL. The low boiling point distillate in the production of MS, discharged from the first distillation column in the production of MS, was characterized by a phenol concentration of approximately 90% by weight. After that, the second distillation column PL was operated at 50 torr and a reflux ratio of 0.5, and purified s-PL was obtained through the top of the column at a capacity of approximately 27 kg / h. On the other hand, a liquid PL-containing mixture containing DPC, BPA and oligomers in amounts of 67 wt.%, 7 wt.% And 4 wt.%, Respectively, was continuously discharged as bottoms at a capacity of approximately 2.2 kg / hour.

Experimental Example 1

Getting DPC

First, a detailed explanation will be given regarding the method by which dehydrated s-PL discharged as distillate from the second distillation column PL shown in FIG. 5 was used as starting material for DPC in the preparation of DPC, while low boiling distillate in upon production of PC (D6), resulting from s-PL dehydration in the first distillation column PL 30, was recycled to the DPC washing step.

The reaction stage upon receipt of the DPC / stage dehydrochlorination

The stage of obtaining DPC was carried out in accordance with the flowchart shown in figure 1. Incidentally, the used DPC 1 production reactor consisted of two reactors connected in series.

Purified s-PL in a molten state, characterized by a temperature of 50 ° C, at a flow rate of 30.0 kg / hr (0.32 kmol / hr), was continuously fed into the first DPC production reactor together with PL containing pyridine as a catalyst, obtained by dehydration of low boiling compounds discharged as distillate from the distillation column of low boiling compounds described below. When carrying out such a feed, the purified s-PL was heated to 150 ° C. With sufficient stirring, phosgene gas (CDC) was continuously fed into the first DPC reactor at a flow rate of 3.56 nm ³ / hr (0.16 kmol / hr). The reaction mixture, which flowed from the first DPC production reactor and contained the gas / liquid mixture phase, was fed to the second DPC production reactor through a bypass pipe. For the contents in the second DPC production reactor, with sufficient stirring, adjustments were also made to withstand temperatures of 150 ° C. The liquid reaction mixture was supplied to the dehydrochlorination column 2. In the dehydrochlorination column 2 at 160 ° C., countercurrent contacting was carried out using nitrogen gas in order to ensure that the phenyl chloroformate obtained as an intermediate was completely introduced into the reaction and PL. Dehydrochlorinated liquid b, characterized by a DPC concentration of approximately 89% by weight, was continuously discharged from the bottom of the dehydrochlorination column 2. Almost 100% of the supplied phosgene was converted to DPC. On the other hand, the exhaust gases resulting from the DPC synthesis (D1; the reaction gas discharged from the second DPC production reactor and the nitrogen-containing gas discharged from the dehydrochlorination column 2) were mixed with each other and then cooled to 10 ° С . The resulting condensate was returned to the second DPC production reactor, while for the hydrogen chloride obtained in the form of non-condensed gas, neutralization was performed under the action of an aqueous alkaline solution and release.

DPC flushing step / DPC water flushing step

The obtained dehydrochlorinated liquid, b, was fed into the mixing tank 3 together with the recovered liquid containing DPC, d, recovered from the extraction / distillation column described below in the preparation of DPC 8. Thereafter, the mixture was fed into an alkaline neutralization tank 4 equipped with a Teflon lining. An aqueous solution of sodium hydroxide with a concentration of approximately 5 wt.% (Liquid obtained by mixing an aqueous solution of sodium hydroxide with a concentration of 25 wt.% With the aqueous phase isolated after the subsequent stage of water washing and low boiling distillate in the preparation of RS obtained in the above-described purification step s-PL). The contents were stirred at 80 ° C. for approximately 10 minutes, and then adjusted to obtain a pH value of 8.5. This mixture was allowed to stand for separation and the separated organic phase was passed into a water washing vessel 5. On the other hand, the aqueous phase remaining after separation (which contains PL and sodium chloride) was brought into contact with water vapor, as a result of which almost completely present PL recovered as a low boiling point distillate. This distillate was fed to a water washing vessel 5 in a subsequent step. In the water washing vessel 5, the organic phase was washed using warm water in an amount of approximately 30% by weight, based on the amount of organic phase. The aqueous phase (which was recycled to the neutralization / mixing vessel) was isolated and a water-washed liquid was obtained, f, which was a crude DPC (containing water, a pyridine catalyst, and PL).

DPC distillation step / low boiling point distillation step

After that, the liquid subjected to water washing, f, and an aqueous solution of sodium hydroxide with a concentration of 0.1 N. continuously fed to the middle plate of the first distillation column upon receipt of DPC 6 at a flow rate of approximately 42 kg / h and 70 ml / h, respectively. As this first distillation column, in the preparation of DPC 6, a continuous distillation column was used, characterized by the number of theoretical plates equal to 8, which had an internal diameter of 150 mm and a height of 4.0 m, was equipped with a reflux apparatus on top, and had in its middle a portion for supplying the initial material and had a concentration section and a recovery section, each of which was packed with Sulzer Packing (manufactured by Sumitomo Heavy Industries, Ltd.). The distillation was carried out under conditions of a degree of evacuation of 20 torr, a temperature of the heat transfer oil of approximately 220 ° C, a column top temperature of 80-100 ° C, and a reflux ratio of 1 to distill the mixed gas F containing compounds having a boiling point lower than the boiling point of DPC, i.e. water, a pyridine catalyst and unreacted PL. After dehydration of the mixed gas F, part of the gas was vented, and the rest was fed to the first DPC reactor. On the other hand, the residue after the first distillation g, mainly consisting of DPC, was discharged from the bottom of the column at a capacity of approximately 37 kg / h. It was impossible to detect water in it (10 ppm or less), it was impossible to detect the levels of pyridine and PL (1 ppm or less) and 50 ppm, respectively.

DPC distillation step / High boiling point distillation step

In addition, the residue after the first distillation g was continuously fed into the second distillation column to obtain DPC 7. As the second distillation column when receiving DPC 7, a continuous distillation column was used, characterized by the number of theoretical plates equal to 8, which had an inner diameter of 200 mm and a height 4.0 m, was equipped with a reflux apparatus on top, had in its middle part for supplying the starting material, and had a concentration section and an extraction section, each of which was filled with Sulzer Packing (produced led by Sumitomo Heavy Industries, Ltd.). The distillation was carried out under conditions of a degree of evacuation of 20 torr, a temperature of the heat transfer oil of approximately 240 ° C, a top temperature of the column of approximately 180 ° C, a reflux ratio of 0.5, and a proportion of distillate of approximately 90%. As a result, purified DPC was obtained through the top of the column at a capacity of approximately 33.5 kg / h, and the residue after distillation upon receipt of DPC (X1), which was a high boiling point compound, was removed from the bottom of the column at a capacity of approximately 4 kg / h . This purified DPC was a high purity product containing 80 ppm PL.

The stage of extraction / distillation upon receipt of the DPC

In addition, the distillation residue upon receipt of DPC (X1) discharged from the bottom of the distillation column of high boiling compounds was simultaneously fed to the recovery / distillation column upon receipt of DPC 8 for continuous distillation under the following conditions. The recovered liquid containing DPC, d, recovered through the top of the column at a capacity of approximately 3.5 kg / h, was recycled to mixing tank 3, while the bottom residue from the recovery / distillation column in the preparation of DPC 8 was continuously withdrawn at productivity approximately equal to 0.2 kg / hour. As regards the extraction / distillation conditions upon receipt of the DPC, a continuous distillation column was used, characterized by the number of theoretical plates equal to 8, which had an inner diameter of 100 mm and a height of 3.0 m, was equipped with a reflux apparatus on top, and had a supply section in the middle the source material and had a concentration section and a recovery section, each of which was packed with Sulzer Packing (manufactured by Sumitomo Heavy Industries, Ltd.). Distillation was carried out under conditions of a degree of evacuation of 20 torr, a temperature of the heat-transfer oil approximately equal to 240 ° C, a top temperature of the column of 180 ° C and a reflux ratio of 0.5. In the residue after extraction / distillation in the preparation of DPC (X1 '), which was the bottom residue from the extraction / distillation column in the preparation of DPC 8, alkyl substituted DPC derivatives and brominated substituted DPC derivatives were found in amounts of approximately 7000 ppm (wt.) and approximately 800 ppm (wt.), respectively.

Reference example 1

Getting DPC

DPC was obtained by the same method as in Experimental Example 1, except that commercial PL (manufactured by Mitsubishi Chemical Corp.) was used instead of purified s-PL.

results

We made sure that, even if s-PL was used, the same yield was obtained as in the case of using commercial PL, and the production efficiency was ensured.

Comparative Example 1

Getting DPC

DPC was obtained by the same method as in Experimental Example 1, except that s-PL (water content of 0.3 wt%) was used obtained bypassing the first distillation column of PL at the purification stage s -PL. As a result, due to hydrolysis at the reaction stage for DPC, the concentration of DPC in dehydrochlorinated liquid b decreased to 86 wt.%, Which resulted in a significant deterioration in the production efficiency.

Reference example 2

Getting BPA

The stage of obtaining BPA

BPA was obtained in accordance with the schemes of technological processes shown in figure 2-4, as follows. In a 60-liter thermostatic BPA reactor equipped with a thermostat, a packing in the form of an acidic cation exchange resin in the form of sulfonic acid (trade name DIAION SK-104, manufactured by Mitsubishi Chemical Corp.), in which 15% of sulfo groups was neutralized, was placed action of 4-pyridinethanethiol. A liquid mixture of PL and acetone with a molar ratio of 10: 1 was introduced into this BPA reactor at a temperature of 80 ° C and a flow rate of 68.2 kg / hr, ensuring the reaction between them. The degree of conversion of acetone was 80%. After the low boiling compounds (unreacted acetone, water, and part of PL) were removed at a rate of 5.1 kg / h, the reaction mixture was cooled to 50 ° C, thereby precipitating adduct crystals. This mixture was filtered to separate it into adduct crystals and mother liquor. The productivity upon receipt was 16.5 kg / h and 46.5 kg / h, respectively. Ten weight percent of this mother liquor was fed to the mother liquor processing stage, while for the rest of the mother liquor as a part of the starting material introduced into the BPA production reactor, circulation was performed.

The adduct crystals thus obtained were redissolved in PL supplied at a flow rate of 27.2 kg / h. The resulting solution was cooled to 50 ° C, achieving crystal precipitation, and then filtered to separate adduct crystals (11.3 kg / h) from the mother liquor (32.5 kg / h). The isolated crystals were heated to 180 ° C. under reduced pressure of 0.3 mm Hg to remove PL. Thus, with a capacity of 7.7 kg / h, BPA was obtained, characterized by a degree of purity of 99.95% or more.

The mother liquor supplied to the mother liquor processing step was processed using the PL evaporator shown in FIG. 4 to distill part of the PL and concentrate the mother liquor. After that, 0.1 wt.% Sodium hydroxide was added to the mother liquor, and then the mother liquor was introduced into the lower part of residue processing reactor 14, in which, as a result of adjustment, a reduced pressure of 50 mmHg and a temperature of 210 ° C were maintained. This reactor was operated under such conditions in order to withstand the constancy of the liquid level in the lower part (residence time 1 hour), and the lower product in residue processing reactor 14 was withdrawn from the system at a capacity of 0.5 kg / h. In addition, the distillate discharged through the top of residue processing reactor 14 was mixed with PL, and this mixture, at a flow rate of 4.2 kg / h, was introduced into a flow-type regeneration reactor 15 equipped with a 4 liter packing of acid cation exchange resin in the form sulfonic acid (trade name DIAION SK-104, manufactured by Mitsubishi Chemical Corp.). The reaction for the mixture was carried out at 80 ° C. For the obtained liquid reaction mixture, circulation was carried out with feeding to the BPA production reactor used in the initial stage.

Low-boiling compounds (unreacted acetone, water and part of PL) obtained by isolation from the reaction mixture were introduced into the PL recovery column at a flow rate of 5.1 kg / h. At the same time, ethylbenzene (an additive for breaking the azeotrope) was fed through the top of the column. As a result, a liquid mixture of acetone, water and ethylbenzene was discharged through the top of the PL recovery column at a capacity of 2.4 kg / h, while PL was discharged from the bottom of the column at a capacity of 3.5 kg / h. In addition, a distillate (acetone, water and ethylbenzene) discharged from the top of the PL recovery column was introduced into the acetone recovery column. Acetone was discharged from the top of the acetone recovery column at a capacity of 0.7 kg / h, while a mixture of water and ethylbenzene was discharged through the bottom of the column at a capacity of 1.6 kg / h. For PL obtained through the cube of the PL recovery column and acetone obtained through the top of the acetone recovery column, as part of the starting materials introduced into the synthesis reactor, circulation was performed.

In addition, acetone and purified PL were additionally fed into the synthesis reactor in amounts corresponding to the quantities withdrawn from the system and the amount of BPA obtained. Namely, acetone and purified PL were supplied at a flow rate of 2.9 kg / h and 15 kg / h, respectively, providing a continuous synthesis reaction of BPA. Thus, the entire system functioned with continuous receipt of BPA. The BPA obtained in this case was introduced into the polymerization step described above in the preparation of RS to obtain RS.

The purified PL used above was a substance obtained by processing commercial PL for industrial use (water concentration 0.1 wt.%; Impurity concentration 0.05 wt.%; Hydroxyacetone concentration 20 ppm) by contacting the material DIAION SK-104H, trade name for a resin manufactured by Mitsubishi Chemical Corp., at 80 ° C for a contact time of 50 minutes, followed by distillation of PL in a distillation column characterized by a column temperature of 175 ° C and a pressure of ha column 560 mmHg when extracting PL through the top. The level of hydroxyacetone in this purified PL was 1 ppm or less.

Experimental Example 2

Getting BPA

The following is an explanation of a method in which dehydrated s-PL discharged as a distillate from a second distillation column PL shown in FIG. 5 was used as starting material for BPA in producing BPA, while low boiling point distillate in obtaining RS (D6) resulting from s-PL dehydration was returned to the BPA / water separation step.

The low boiling compounds (unreacted acetone, water and part PL) obtained by separating the reaction mixture in the BPA preparation step (Reference Example 2) (5.1 kg / h) were mixed with a low boiling distillate obtained through the top of the first distillation column in the s-PL purification step described above. This mixture was introduced into the PL recovery column and, at the same time, ethylbenzene (additives for breaking the azeotrope) was fed through the top of the column. As a result, a liquid mixture of acetone, water and ethylbenzene was discharged through the top of the PL recovery column at a capacity of 2.5 kg / h, while PL was discharged from the bottom of the column at a capacity of 4.0 kg / h. In addition, the distillate (acetone, water and ethylbenzene) discharged through the top of the PL recovery column was introduced into the acetone recovery column. Acetone was discharged from the top of the acetone recovery column at a capacity of 0.7 kg / h, while a mixture of water and ethylbenzene was discharged from the bottom of the column at a capacity of 1.7 kg / h. For PL obtained through the cube of the PL recovery column and acetone obtained through the top of the acetone recovery column, as part of the starting materials introduced into the synthesis reactor, circulation was performed.

In addition, acetone and PL, which was purified s-PL, obtained through the top of the second PL distillation column in the PL distillation step described above, were additionally fed to the BPA production reactor in amounts corresponding to the quantities withdrawn from the system and the amount of BPA obtained. Namely, acetone and PL were supplied at a flow rate of 2.9 kg / h and 14.5 kg / h, respectively, providing a continuous synthesis reaction. In this way, the entire system functioned, providing continuous receipt of BPA. In addition, the BPA obtained in this case was introduced into the polymerization step described above to obtain PC.

As a result, due to sending the low boiling distillate obtained through the top of the first distillation column in the s-PL purification step to recycling to the existing step in the BPA preparation step, almost all of the amount of PL contained in the low boiling distillate can be effectively recovered as starting material in the preparation of the BPA. During the operation described above, BPA and MS were obtained by the method described above. As a result of the obtained BPA and RS, the quality-related problem is completely unusual.

Reference Example 2

Getting BPA

BPA was obtained by the same method as in Experimental Example 2, except that instead of purified s-PL, s-PL was used (water content of 0.3 wt%, obtained bypassing the first distillation column of PL during the s-PL purification step. As a result, a decrease in the BPA yield was observed. The reason for this seems to be that the water present caused a decrease in the activity of the ion exchange resin as a reaction catalyst.

Reference Example 3

Getting BPA

BPA was obtained in the same manner as in reference example 2, except that instead of purified PL in reference example 2, commercial PL was used for industrial use. As a result, the output of the BPA gradually decreased. We made sure that the hydroxyacetone present caused a decrease in catalytic activity.

Example 2

When using experimental examples, the following are explanations for the processing of steam-converted ingredients in the production of MS at the polymerization stage in the preparation of MS for the case of s-PL 2 processing.

DPC Production Example (1)

An example in which DPC is obtained from commercial PL and CDC is shown below.

Reaction stage

During continuous feeding of molten commercial PL and pyridine catalyst into the reactor with stirring at 150 ° C., phosgene gas was continuously fed. Hydrogen chloride gas obtained as a by-product from phosgenation was cooled to 10 ° C. The resulting condensate was returned to the reactor, and neutralization was carried out for the non-condensing gas using an aqueous alkaline solution, and then thereafter. On the other hand, a liquid reaction mixture containing approximately 91 wt.% DPC was continuously discharged from the reactor. The degree of conversion of phosgene at the reaction stage was almost 100%.

Flushing Stage

The liquid reaction mixture and an aqueous solution of sodium hydroxide with a concentration of approximately 5% by weight were fed to a neutralization / mixing vessel equipped with a Teflon lining. For the contents, stirring was carried out at 80 ° C. for approximately 10 minutes and an adjustment was made to maintain a pH value of 8.5. After neutralization, the organic phase was separated using sedimentation, and then transferred to a tank of water washing / stirring. In an aqueous wash / stir tank, the organic phase was washed using warm water in an amount of approximately 30% by weight, based on the amount of organic phase. The aqueous phase was separated to obtain a crude DPC (containing 1 wt.% Water, 2 wt.% Pyridine, 8 wt.% PL and 89 wt.% DPC).

Stage distillation of low boiling compounds

Thereafter, a “crude” DPC was continuously fed to the middle plate of the low boiling point distillation column at a flow rate of approximately 30 kg / h. As this distillation column of low boiling compounds, a continuous distillation column was used, characterized by the number of theoretical plates equal to 8, which had an internal diameter of 150 mm and a height of 4.0 m, was equipped with a reflux apparatus on top, had a feed part in the middle and had a concentration section and a recovery section, each of which was packed with Sulzer Packing (manufactured by Sumitomo Heavy Industries, Ltd.). The distillation was carried out under conditions of a degree of evacuation of 20 torr, a temperature of the heat transfer oil of approximately 220 ° C, a column top temperature of 80-100 ° C, an average plate temperature of 160 ° C and a reflux ratio of 1 to distill compounds with a lower boiling point compared to the boiling point of DPC, i.e. water, pyridine and PL. DPC (water levels of 10 ppm (wt.) Or less; pyridine 1 ppm (wt.) Or less; PL 50 ppm (wt.) Were continuously discharged from the bottom of the column at a capacity of approximately 26 kg / h; .)).

Stage distillation of high boiling compounds

In addition, this DPC (VAT residue from the low boiling point distillation column) was continuously fed to the high boiling point distillation column. As this distillation column of high-boiling compounds, a continuous distillation column was used, characterized by the number of theoretical plates equal to 8, which had an inner diameter of 200 mm and a height of 4.0 m, was equipped with a reflux apparatus on top, had a feed part in the middle and had a concentration section and a recovery section, each of which was packed with Sulzer Packing (manufactured by Sumitomo Heavy Industries, Ltd.). Distillation was carried out under conditions of a degree of evacuation of 20 torr, a temperature of the heat-transfer oil of approximately 240 ° C, a top temperature of the column of approximately 180 ° C and a reflux ratio of 0.5. As a result, through the top of the column at a productivity of approximately 23.5 kg / h, purified DPC was obtained, and high boiling compounds (DPC containing approximately 350 ppm (wt.) Alkyl substituted DPC derivatives and about 40 ppm (wt.) brominated derivatives DPC) was withdrawn from the bottom of the column at a capacity of approximately 2.5 kg / h. Purified DPC was a high purity product containing PL in an amount equal to 80 ppm (wt.).

DPC Production Example (2)

An example in which DPC was obtained from commercial PL and dimethyl carbonate is shown below.

Reaction stage

A liquid starting material containing commercial PL, dimethyl carbonate and tetraphenoxy titanium as a catalyst was supplied at a flow rate of 600 g / h (dimethyl carbonate 390 g / h; PL 200 g / h; tetraphenoxy titanium 0.5 g / h) on a tenth plate, counting from the top of a plate type distillation column (first reaction / distillation column), characterized by the number of actual plates, 50, and having an inner diameter of 50 mm, and a height of 5 m. The reaction / distillation was carried out during heating of the column cube using heating co the bucket. A dimethyl carbonate solution containing methanol was discharged from the top of the column while boiling the solution under reflux conditions at reflux number 12. The bottom residue, which contained the obtained methyl phenyl carbonate and a small amount of DPC, was discharged from the bottom of the column and fed to the tenth plate, counting from the top of the distillation column column-type (columns of the second reaction / distillation), characterized by the number of actual plates equal to 50, and having an inner diameter of 80 mm, and a height of 4 m. In the column of the second reaction / distillation reaction to proceed further, and a liquid containing methyl phenyl carbonate DPC, and the resultant was discharged from the column bottom. The bulk of the dimethyl carbonate remaining unreacted and the portion of PL remaining unreacted were distilled off through the top of the second reaction / distillation column and recycled to the first reaction / distillation column.

Recycling Stage

A methanol-containing solution of dimethylcarbonate discharged as a distillate from the first reaction / distillation column was fed to the middle plate of the distillation column (azeotropic distillation column), characterized by the number of actual plates, equal to 30, and having an inner diameter of 32 mm and a height of 2, 5 m. The distillation was carried out with a reflux number equal to 5. A liquid mixture of methanol and dimethyl carbonate, which had a composition close to the azeotropic composition, was discharged through the top of the column, and then fed to the extraction / distillation th column. Methanol was isolated from the dimethyl carbonate in the extraction / distillation column. Methanol was removed from the system, while dimethyl carbonate was recycled to the first reaction / distillation column. For the bottom residue from the azeotropic distillation column, which was dimethyl carbonate containing a small amount of PL, was circulated with the first reaction / distillation being introduced into the column.

Purification stage

A high boiling point reaction mixture, which was continuously discharged from the bottom of the second reaction / distillation column and which contained catalyst and DPC, was introduced into an evaporator from which condensate containing catalyst was removed. On the other hand, steam-converted ingredients including a large amount of DPC obtained in an evaporator were supplied to a diphenyl carbonate purification column. The cleaning column was adjusted so as to withstand the pressure of the top of the column 20 torr and the temperature of the column cube 190 ° C. A low boiling point mixture containing phenol and methyl phenyl carbonate was discharged as distillate through the top of the column. A portion of this mixture was boiled under reflux conditions, and the remainder was recycled to a second reaction / distillation column. On the other hand, high boiling impurities were removed from the bottom of the diphenyl carbonate purification column, and DPC was obtained from the middle plate of the column.

The operations described above were continuously performed until a steady state was reached at each stage. Then, when the steady state was reached in the stages, a diphenyl carbonate sample was taken and analyzed by high performance liquid chromatography. As a result, 300 ppm (wt.) Methyl phenyl carbonate was found in the resulting diphenyl carbonate. The DPC yield was approximately 95% based on the amount of PL.

An example of obtaining BPA

The following is an example in which BPA was prepared from commercial PL and acetone.

A 60-liter packing in the form of an acidic cation exchange resin in the form of sulfonic acid (trade name DIAION SK-104, manufactured by Mitsubishi Chemical Corp.), in which 15% of the sulfo groups was neutralized by the action, was placed in a 60-liter synthesis reactor equipped with a thermostat 4-pyridinethanethiol. A liquid mixture of PL and acetone with a molar ratio of 10: 1 was introduced into this synthesis reactor at a temperature of 80 ° C and a flow rate of 68.2 kg / h, providing a reaction between them. The degree of conversion of acetone was 80%. After the low-boiling compounds (unreacted acetone, water, and part of PL) were discharged at a capacity of 5.1 kg / h, the reaction mixture was cooled to 50 ° C, to precipitate adduct crystals. This mixture was filtered to separate it into adduct crystals and mother liquor. The productivity upon receipt was 16.5 kg / h and 46.5 kg / h, respectively. Ten weight percent of this mother liquor was fed to the mother liquor processing stage, while circulation was carried out for the remaining mother liquor as part of the starting material introduced into the synthesis reactor.

The adduct crystals thus obtained were redissolved in PL supplied at a flow rate of 27.2 kg / h. The resulting solution was cooled to 50 ° C, achieving crystal precipitation, and then filtered to separate adduct crystals (11.3 kg / h) from the mother liquor (32.5 kg / h). The isolated crystals were heated to 180 ° C under reduced pressure equal to 0.3 mm Hg to remove PL. Thus, with a capacity of 7.7 kg / h, BPA was obtained, characterized by a degree of purity of 99.95% or more.

On the other hand, the mother liquor supplied to the mother liquor processing step was concentrated by distillation of a portion of the PL. After that, 0.1 wt.% Sodium hydroxide was added to the mother liquor, and then the mother liquor was introduced into the cube of the decomposition / distillation column, in which, as a result of adjustment, a reduced pressure of 50 mmHg and a temperature of 210 ° C were maintained. This column was operated under such conditions to maintain a constant liquid level in the lower part (residence time 1 hour), and the bottom residue in the decomposition / distillation column was removed from the system at a capacity of 0.5 kg / hour. In addition, the distillate discharged through the top of the decomposition / distillation column was mixed with PL, and this mixture, at a flow rate of 4.2 kg / h, was introduced into a flow-type reactor equipped with a 4 liter packing of acidic cation exchange resin in the form of sulfonic acid (trade name DIAION SK-104, manufactured by Mitsubishi Chemical Corp.). The reaction for the mixture was carried out at 80 ° C. For the resulting liquid reaction mixture, circulation was carried out with the synthesis reactor used in the initial stage being fed.

Commercial PL (18.5 kg / hr) and acetone (3.6 kg / hr) were additionally fed into the synthesis reactor in amounts corresponding to the amounts withdrawn from the system and the amount of bisphenol A obtained. Thus, the synthesis reaction was carried out continuously, and the whole system functioned with continuous receipt of BPA.

An example of obtaining RS (1)

The following is an example in which, during the steps shown in FIG. 6, from the DPC obtained in the above example to obtain DPC (1) and the BPA obtained in the above example to obtain BPA, PC was obtained.

Stage polymerization upon receipt of RS

In an atmosphere of gaseous nitrogen, DPC and BPA were mixed in the melt at a ratio of 0.977 (wt.) Using a mixing vessel 21. This mixture was continuously fed into the first vertical polymerization reactor with stirring 22 in a nitrogen atmosphere, in which the temperature was kept at 210 ° C and adjusted pressure 100 torr. The liquid level was kept constant by adjusting the degree of openness of the valve located on the polymer discharge line connected to the lower part of the tank so as to obtain an average residence time of 60 minutes. In addition, simultaneously with the initiation of the feed of the mixture of starting materials as a catalyst, cesium carbonate in the form of an aqueous solution began to be continuously fed at a flow rate of 0.5 · 10 ^-6 mol per one mol of BPA. After that, the liquid polymerization reaction mixture discharged from the lower part of the vessel was continuously fed sequentially to the second and third vertical polymerization reactors 23 and 24 and the fourth horizontal polymerizer 25. During the course of the reaction, the liquid level in each vessel was adjusted so as to obtain an average a residence time of 60 minutes, and at the same time, the PL obtained as a by-product was distilled off. The gases obtained by evaporation and released respectively from the first and second polymerization reactors 22 and 23 were condensed and liquefied using a reflux apparatus 33a and 33b, respectively, and using multi-stage condensers 26 and 27, respectively. A portion of each of the resulting condensates as a result of boiling under reflux conditions was supplied to the polymerization reactor, and the remainder was recovered and stored in the first tank for recovered PL 29a upon receipt of RS. On the other hand, the gas obtained by evaporation and discharged from the third polymerization reactor 24 was cured using one of two freezing capacitors arranged in parallel. The resulting solid phase was melted by switching to another freezing capacitor and recovered and stored in a second tank for recovered PL 29b upon receipt of the PC. During this operation, the entire amount of steam-converted ingredients in the production of MS, produced as distillates from the first and second polymerization reactors 22 and 23, was stored in the first tank for recovered PL 29a in the production of MS, while the steam-converted ingredients in the production of PC PCs discharged as a distillate from the third polymerization reactor 24 were stored in a second reservoir for recovered PL 29b upon receipt of the PC.

The polymerization conditions for each polymerization reactor were as follows: first polymerization reactor 22 (210 ° C, 100 torr), second polymerization reactor 23 (240 ° C, 15 torr), third polymerization reactor 24 (260 ° C, 0.5 torr ) and the fourth polymerization unit 25 (280 ° C, 0.5 torr).

The resulting polymer in the molten state was introduced into a twin-screw extruder (manufactured by Kobe Steel, Ltd .; worm diameter 0.046 m; L / D = 40.2) and granulated while adding butyl p-toluenesulfonate in an amount of 5 h / million (wt.) when calculating the amount of polycarbonate. Thus, the obtained PC was characterized by a Mv value of 21,000 and an initial value of YI of 1.7. The methods used to measure molecular weight (Mv) and initial hue (YI) have been described above.

Steam-Turned Ingredients on PC

For each of the steam-converted ingredients in the production of MS, recovered at the polymerization stage, a study was conducted to determine its amount and composition. The results obtained were as follows.

The first tank for the recovered PL 29a upon receipt of PC

The amount of phenol in the recovered first steam-converted ingredients upon receipt of RS p1 was approximately 60% based on the total amount of PL distilled off during the polymerization step upon receipt of RS. In addition to PL, 1.1 wt.% DPC was detected. BPA and oligomeric ingredients were not found.

The second tank for the recovered PL 29b upon receipt of RS

The amount of phenol in the recovered second steam-converted ingredients upon receipt of RS p2 was approximately 40% based on the total amount of PL distilled off in the polymerization step. In addition to PL, 6.0 wt% DPC was detected. In addition, BPA and oligomeric ingredients were found in amounts of 1.2 wt.% And 0.3 wt.%, Respectively.

An example of obtaining RS (2)

The following is an example in which, from the DPC obtained in the above example of obtaining DPC (2) and the BPA obtained in the above example of obtaining BPA, PC was obtained.

Stage polymerization upon receipt of RS

The same procedure was used as in the PC (1) preparation example above, except that the DPC used in the DPC production example (2) above was used as the DPC. The resulting PC was characterized by a Mv value of 21,000 and an initial value of YI of 1.7. It had the same quality as the quality of PC obtained in the above example of producing aromatic polycarbonate (1).

Steam-Turned Ingredients on PC

For each of the steam-converted ingredients in the production of MS, recovered at the polymerization stage, a study was conducted to determine its amount and composition. The results obtained were as follows.

The first tank for the recovered PL 29a upon receipt of PC

The amount of phenol in the recovered first steam-converted ingredients upon receipt of RS p1 was approximately 60% based on the total amount of PL distilled off during the polymerization step upon receipt of RS. In addition to PL, 1.1 wt% DPC and 95 ppm methanol were found. BPA and oligomeric ingredients were not found.

The second tank for the recovered PL 29b upon receipt of RS

The amount of phenol in the recovered second steam-converted ingredients upon receipt of RS p2 was approximately 40% based on the total amount of PL distilled off in the polymerization step. In addition to PL, 6.0 wt% DPC was detected. In addition, BPA and oligomeric ingredients were found in amounts of 1.2 wt.% And 0.3 wt.%, Respectively. No methanol was detected (5 ppm (wt.) Or less).

Experimental Example 1

To obtain DPC and BPA, steam-converted ingredients were used in the preparation of MS, containing phenol as a by-product and obtained in the above example of the preparation of MS (1).

Getting DPC

DPC was obtained using the same methodology as in the above example of obtaining DPC (1), except that 60% of the commercial PL used in the example of obtaining DPC (1) was replaced by the first steam-converted ingredients in the preparation of PC p1 extracted in the above example of obtaining RS (1). As a result, the degree of phosgene conversion at the reaction stage and the quality of the obtained DPC were the same as in the example of obtaining DPC (1), and were satisfactory.

Getting BPA

BPA was obtained using the same methodology as in the above example of obtaining BPA, except that 40% of commercial PL, additionally continuously fed to the synthesis reactor in the example of obtaining BPA, was replaced by second, steam-converted ingredients in the preparation of PC P2 extracted in the above example of obtaining RS (1). As a result, the degree of conversion of acetone and the quality of bisphenol A were satisfactory.

Experimental Example 2

To produce DPC and BPA, steam-converted ingredients were used in the preparation of MS, containing phenol as a by-product and obtained in the above example of the preparation of MS (2).

Getting DPC

DPC was obtained using the same methodology as in the above example of obtaining DPC (2), except that 60% of the commercial PL used in the example of obtaining DPC (2) was replaced by the first steam-converted ingredients in the preparation of PC p1 extracted in the above example of obtaining RS (2). As a result, you could get a DPC that has the same quality. We made sure that even if methanol obtained from methyl phenyl carbonate got into the system, this did not pose any problem.

Getting BPA

BPA was obtained using the same methodology as in the above example of obtaining BPA, except that 40% of commercial PL, additionally continuously fed to the synthesis reactor in the example of producing BPA, was replaced with second steam-converted ingredients in the preparation of RS p2 extracted in the above example of obtaining RS (2). As a result, the degree of conversion of acetone and the quality of the BPA were satisfactory. In addition, methanol concentrations in the starting materials used for the reaction were not found.

Comparative experimental example 1

To obtain DPC, the second, steam-converted ingredients were used in the preparation of RS p2, recovered in the above example of obtaining RS (1).

Getting DPC

DPC was obtained using the same methodology as in the above example of obtaining DPC (1), except that the entire amount of commercial PL used in the example of obtaining DPC (1) was replaced with the second steam-converted ingredients in the preparation of PC P2 extracted in the above example of obtaining RS (1). As a result, the pipeline for transferring the liquid reaction mixture to the washing stage was subject to clogging, which made it impossible to continue functioning.

Comparative experimental example 2

To obtain BPA, the first steam-converted ingredients were used to obtain RS p1, extracted in the above example of obtaining RS (2).

Getting BPA

BPA was continuously produced by the same method as in the BPA production example above, except that the entire amount of commercial PL further continuously fed to the synthesis reactor in the BPA production example was replaced with the first steam-converted ingredients in the preparation of PC p1 (containing 95 ppm (wt.) methanol) recovered in the above example of obtaining RS (2). As a result, the degree of conversion of acetone was significantly reduced, that is, to 55.0%. It appears that the methanol present caused a deterioration in the performance of the catalyst. The concentration of methanol in the phenol starting material during the synthesis reaction was approximately 30 ppm (wt.) Due to dilution using a circulating mother liquor.

Example 3

When using the experimental examples, the following is an explanation of the classification by impurities for methods of using steam-converted ingredients in the production of PC p and commercial PL for the case of processing s-PL 3.

Experimental Example 1

Getting DPC

Reaction stage

During continuous feeding into the reactor a molten commercial PL (manufactured by Mitsubishi Chemical Corp .; a cresol level of 45 ppm (wt.); A hydroxyacetone level of 27 ppm (wt.); Hereinafter, referred to as "PL1") and the pyridine catalyst with stirring at 150 ° C, a continuous supply of gaseous phosgene was carried out. Hydrogen chloride gas obtained as a by-product from phosgenation was cooled to 10 ° C. The resulting condensate was returned to the reactor, and neutralization was carried out for the non-condensing gas using an aqueous alkaline solution, and then thereafter. On the other hand, a liquid reaction mixture containing approximately 91 wt.% DPC was continuously discharged from the reactor.

Flushing Stage

The liquid reaction mixture and an aqueous solution of sodium hydroxide with a concentration of approximately 5% by weight were fed to a neutralization / mixing vessel equipped with a Teflon lining. For the contents, stirring was carried out at 80 ° C. for approximately 10 minutes and an adjustment was made to maintain a pH value of 8.5. After neutralization, the organic phase was separated using sedimentation, and then transferred to a tank of water washing / stirring. In an aqueous wash / stir tank, the organic phase was washed using warm water in an amount of approximately 30% by weight, based on the amount of organic phase. The aqueous phase was separated to obtain a crude DPC (containing 1 wt.% Water, 2 wt.% Pyridine, 8 wt.% PL and 89 wt.% DPC).

Stage distillation of low boiling compounds

Thereafter, a crude DPC was continuously fed to the middle plate of the low boiling point distillation column at a flow rate of approximately 30 kg / h. As this distillation column of low boiling compounds, a continuous distillation column was used, characterized by the number of theoretical plates equal to 8, which had an internal diameter of 150 mm and a height of 4.0 m, was equipped with a reflux apparatus on top, had a feed part in the middle and had a concentration section and a recovery section, each of which was packed with Sulzer Packing (manufactured by Sumitomo Heavy Industries, Ltd.). The distillation was carried out under conditions of a degree of evacuation of 20 torr, a temperature of the heat transfer oil of approximately 220 ° C, a column top temperature of 80-100 ° C, an average plate temperature of 160 ° C and a reflux ratio of 1 to distill compounds with a lower boiling point compared to the boiling point of DPC, i.e. water, pyridine and PL. DPC (water levels of 10 ppm (wt.) Or less; pyridine 1 ppm (wt.) Or less; PL 50 ppm (wt.) Were continuously discharged from the bottom of the column at a capacity of approximately 26 kg / h; .)).

Stage distillation of high boiling compounds

In addition, this DPC (VAT residue from the low boiling point distillation column) was continuously fed to the high boiling point distillation column. As this distillation column of high-boiling compounds, a continuous distillation column was used, characterized by the number of theoretical plates equal to 8, which had an inner diameter of 200 mm and a height of 4.0 m, was equipped with a reflux apparatus on top, had a feed part in the middle and had a concentration section and a recovery section, each of which was packed with Sulzer Packing (manufactured by Sumitomo Heavy Industries, Ltd.). Distillation was carried out under conditions of a degree of evacuation of 20 torr, a temperature of the heat-transfer oil of approximately 240 ° C, a top temperature of the column of approximately 180 ° C and a reflux ratio of 0.5. As a result, through the top of the column at a capacity of approximately 23.5 kg / h, a purified DPC (containing 80 ppm (wt.) PL) was obtained.

Reference example 1

DPC was obtained by the same method as in experimental example 1, except that instead of commercial PL (PL1) phenol was used as a by-product (cresol content 5 ppm (wt.); Hydroxyacetone content 1 ppm million (wt.) or less; hereinafter referred to as "PL2"), obtained by distillation / purification under the following conditions of steam-converted ingredients to produce PC p obtained from a PC manufacturing plant at Mitsubishi Chemical Corp.

Distillation / purification conditions

In the first distillation column, the water present was distilled off together with a part of PL at 200 torr and a reflux ratio of 2. The resulting bottoms were continuously fed into the second distillation column. In a second distillation column through the top of the column at 50 torr and a reflux ratio of 0.5, purified phenol by-product was obtained. A liquid PL-containing mixture containing high-boiling ingredients, i.e., DPC, BPA and oligomers, was continuously withdrawn as bottoms.

results

Even when a commercial PL without purification was used to obtain DPC, a high purity DPC was obtained, characterized by a high degree of purity and no discoloration, and the like, as in the case of using a by-product of phenol that was subjected to distillation / purification.

Experimental Example 2 and Comparative Example 1

Getting BPA

A packing in the form of a cation exchange resin with sulfonic acid (a crosslinked sulfonated styrene / divinylbenzene copolymer (DIAION SK104H manufactured by Mitsubishi Chemical Corp.)) was placed in the reactor, in which 15 wt.% Sulfo groups were modified by 4- (2- mercaptoethyl) pyridine. A starting material fluid consisting of any PL (PL2 or PL1) and acetone (manufactured by Mitsubishi Chemical Corp.) (PL: acetone = 13: 1 (molar)), at LHSV (hourly volumetric flow rate of the liquid) 5 hours ^{- 1 was} continuously passed through the reactor using a phenol-moistened catalyst, which allowed the BPA reaction to proceed for 1008 hours at a reaction temperature of 70 ° C. The table shows the degree of conversion of acetone, determined after 120 hours after the initiation of the reaction, the degree of conversion of acetone, determined after 1008 hours after initiation, and the selectivity of BPA. In addition, the ratio between the degree of conversion of acetone determined after 1008 hours after the initiation of the reaction and the degree of conversion of acetone determined after 120 hours after initiation was calculated as an activity preservation parameter. The results of this calculation are also shown in the table.

Phenol The degree of conversion (%) Activity Retention (%) After 120 hours After 1008 hours Experimental Example 2 Pl2 73.8 70.8 94.7 Comparative Example 1 PL1 78.5 58.6 74.6

Incidentally, the degree of conversion (%) and the conservation of catalytic activity (%) were calculated using the following equations:

The degree of conversion (%) = {[(amount of acetone fed) - (amount of unreacted acetone)] / (amount of acetone fed)} × 100

Preservation of activity (%) = [(degree of conversion of acetone after 1008 hours) / (degree of conversion of acetone after 120 hours)] × 100

results

If we used PL obtained by distillation / purification of a PL-containing distillate from the polymerization stage, then, in contrast to the case of using commercial PL, we obtained high degrees of conversion and a high degree of conservation of catalytic activity.

In addition, the use of PL obtained by distillation / purification of the PL-containing distillate from the polymerization step resulted in a BPA having a white color tone, while the use of commercial PL resulted in a BPA that was slightly yellowed. It is assumed that the use of these BPA products in the production of MS results in the following results. In the case where PL obtained by distillation / purification of a PL-containing distillate from the polymerization step was used to obtain BPA, then it seems that a white MS was obtained with a high degree of purity. In contrast, if commercial PL was used to obtain BPA, then it seems that the resulting RS was somewhat yellowed and was characterized by a reduced degree of purity.

Example 4

After this, the invention will be further explained in more detail in connection with the connection of the stages of receipt in accordance with the flowchart shown in Fig.7. In contrast to that shown in Fig. 7, in the interval between the heating / melting step (step (d)) and the PL removal step (step (e)), a storage step for obtaining BPA was arranged.

Experimental Example 1

Getting BPA

In a 60-liter thermostatic BPA reactor equipped with a thermostat, a packing in the form of an acidic cation exchange resin in the form of sulfonic acid (trade name DIAION SK-104, manufactured by Mitsubishi Chemical Corp.), in which 15% of sulfo groups was neutralized, was placed action of 4-pyridinethanethiol. A liquid mixture of PL and acetone (A) with a molar ratio of 10: 1 was introduced into this synthesis reactor at a temperature of 80 ° C and a flow rate of 68.2 kg / h, ensuring the reaction between them. The degree of conversion of acetone (A) was 80%. After the low-boiling compounds (unreacted acetone, water, and part of PL) were discharged at a capacity of 5.1 kg / h, the reaction mixture was cooled to 50 ° C, achieving the precipitation of adduct crystals. This mixture was filtered to separate it into adduct crystals and mother liquor. The productivity upon receipt was 16.5 kg / h and 46.5 kg / h, respectively. 10 wt.% In this mother liquor was fed to the mother liquor processing stage, while circulation was carried out for the remaining mother liquor as part of the starting material introduced into the synthesis reactor.

The adduct crystals thus obtained were redissolved in phenol supplied at a flow rate of 27.2 kg / h. The resulting solution was cooled to 50 ° C, achieving crystal precipitation, and then filtered to separate adduct crystals (11.3 kg / h) from the mother liquor (32.5 kg / h). The isolated crystals were mixed with purified PL supplied at a flow rate of 1.5 kg / h, and a mixture of 60 wt.% BPA and 40 wt.% PL was obtained. This mixture at a flow rate of 12.8 kg / h was introduced into the storage tank upon receipt of the BPA and stored in it (under the following conditions), continuously feeding to the next stage of PL removal at a flow rate of 12.0 kg / h.

The storage tank used when receiving the BPA was a tank made of SUS304 characterized by a capacity of 150 L (for which the value of Vb / Fb indicated in the description was 22). The internal space of the system was sealed, creating an atmosphere of nitrogen, and the temperature in the thickness of the BPA / PL mixture as a result of adjustment was kept at 120 ° C. In addition, in a BPA / PL mixture in an amount of approximately 10 ppm (wt.), PL-sulfonic acid was detected, the source of which appears to be an ion-exchange resin. For this reason, before the mixture was passed into the storage tank, an aqueous solution of caustic soda was added to the mixture to neutralize it in an amount necessary to completely neutralize the acid compound. When the operation was initiated, the liquid level in the storage tank began to increase slightly and gradually.

After that, the mixture BPA / PL in the storage tank upon receipt of BPA was continuously passed to the stage of removal of PL at a flow rate equal to 12.0 kg / h. To remove PL, the mixture was heated to 180 ° C under reduced pressure equal to 0.3 mm Hg. Thus, with a productivity of 7.2 kg / hr (6.8 l / hr), BPA was obtained, characterized by a degree of purity of 99.95% or more. The resulting BPA as such was continuously fed to the aromatic polycarbonate production step, which will be described later.

On the other hand, the mother liquor supplied to the mother liquor processing step (not shown in FIG. 7; see FIG. 4) was processed using a PL 13 evaporator to distill part of the PL and concentrate the mother liquor. After that, 0.1 wt.% Sodium hydroxide was added to the mother liquor, then the mother liquor was introduced into the lower part of the residue processing reactor 14, for which adjustment was made to maintain a reduced pressure of 50 mm Hg and a temperature of 210 ° C. . This reactor operated under such conditions to maintain a constant liquid level in the lower part (residence time 1 hour), and the lower product of the residue processing reactor 14 was withdrawn from the system at a capacity of 0.5 kg / hour. In addition, the distillate discharged through the top of residue processing reactor 14 was mixed with PL, and this mixture, at a flow rate of 4.2 kg / h, was introduced into a flow-type regeneration reactor 15 equipped with a 4 liter packing of acid cation exchange resin in the form sulfonic acid (trade name DIAION SK-104, manufactured by Mitsubishi Chemical Corp.). The reaction for the mixture was carried out at 80 ° C. For the obtained liquid reaction mixture, circulation was carried out with feeding to the BPA production reactor used in the initial stage.

Additionally, commercial PL (18.5 kg / hr) and acetone (3.6 kg / hr) were fed into the BPA production reactor in amounts corresponding to the quantities withdrawn from the system and the amount of BPA produced. Thus, the synthesis reaction was carried out continuously, and the whole system functioned in the continuous production of BPA.

Getting RS

The following is an example in which RS was obtained in accordance with the process diagram shown in FIG. 5.

In an atmosphere of gaseous nitrogen, continuously supplied BPA and DPC were mixed in the melt at a ratio of 1.024 (wt.) Using a mixing vessel 21. This mixture was continuously fed into the first vertical polymerization reactor with stirring 22 in a nitrogen atmosphere, in which the temperature was kept at 210 ° by adjustment C and pressure 100 torr. The liquid level was kept constant by adjusting the degree of openness of the valve located on the polymer discharge line connected to the lower part of the tank, so as to result in an average residence time of 60 minutes. In addition, simultaneously with the initiation of the feed of the mixture of starting materials as a catalyst, cesium carbonate in the form of an aqueous solution began to be continuously fed at a flow rate of 0.5 · 10 ^-6 mol per one mol of BPA. After that, the liquid polymerization reaction mixture discharged from the bottom of the vessel was continuously fed sequentially to the second and third vertical polymerization reactors 23 and 24 and the fourth horizontal polymerization reactor 25. During the course of the reaction, the liquid level in each reactor was adjusted so as to obtain an average residence time of 60 minutes, and at the same time, the PL obtained as a by-product was distilled off. The steam-converted ingredients in the production of RS p, discharged from the first and second polymerization reactors, were condensed and liquefied using appropriate multi-stage capacitors. A portion of each of the resulting condensates as a result of boiling under reflux conditions was supplied to the polymerization reactor, and the remainder was recovered and stored in a PL 29 tank upon receipt of RS. On the other hand, each of the gases obtained by evaporation and discharged from the third and fourth polymerization reactors 24 and 25 was cured using one of two freezing capacitors arranged in parallel. The resulting solid phase was melted by switching to another freezing capacitor and removed and stored in a tank for PL 29 upon receipt of PC (not shown).

The polymerization conditions for each polymerization reactor were as follows: a first polymerization reactor (210 ° C, 100 torr), a second polymerization reactor (240 ° C, 15 torr), a third polymerization reactor (260 ° C, 0.5 torr) and a fourth polymerization reactor (280 ° C, 0.5 torr).

The resulting polymer in the molten state was granulated with simultaneous continuous addition of butyl p-toluenesulfonate in an amount of 5 ppm (wt.) Based on the amount of RS. The polycarbonate thus obtained was characterized by a Mv value of 21,000 and an initial value of YI of 1.8.

Molecular Weight Measurement (Mv)

To measure the specific viscosity (ηsp) using a Ubellode viscometer at a temperature of 20 ° C, a solution in methylene chloride with a concentration of PC (C) of 0.6 g / dl was used, and the molecular weight (Mv) was calculated from the viscosity using the following two equations:

ηsp / С = [η] (1 + 0.28ηsp)

[η] = 1.23Χ10 ^-4 (Mv) ^0.83

Initial Hue Measurement (YI)

RS was dried at 120 ° C for 6 hours in a nitrogen atmosphere, and then using a J-100 injection machine manufactured by The Japan Steel Works, Ltd., a piece having 3 mm thick. This piece was examined using an SC-1 instrument manufactured by Suga Test Instruments Co., Ltd. to obtain a YI value (the higher the YI value, the more PC will be colored).

The above operation was continuously performed for one week. After this, the synthesis / crystallization reaction step was temporarily stopped for approximately 8 hours in order to clean the BPA crystallizer. However, during this entire period, the liquid mixture stored in the storage tank was used to ensure the continuous conduct of the subsequent steps, so that BPA and aromatic polycarbonate could be obtained. The quality of these products obtained during continuous operation for one week, and the quality of products obtained during the subsequent stages after that, were the same as the quality at the very beginning, and were satisfactory.

Experimental Example 2

BPA and aromatic polycarbonate were continuously produced by using the same procedure as in Experimental Example 1, except that the storage tank capacity during BPA production in the BPA production step was changed to 2 m ³ (Vb / Fb = 294). The resulting aromatic polycarbonate was characterized by a Mv value of 21,000 and an initial value of YI of 1.8.

This operation was continuously performed for 2 months. Throughout this period, aromatic polycarbonate showed a color tone (initial YI value) of 1.8-1.9, and the resulting product was satisfactory. Thereafter, the synthesis / crystallization of the BPA was temporarily stopped for approximately 3 days. However, the subsequent steps could be carried out continuously using a liquid mixture stored in a storage tank, and the quality of the product thus obtained was satisfactory. After that, the initial stages when receiving BPA (the stages preceding the storage tank when receiving BPA) were carried out periodically with a 3-day stop at intervals of 2 months, and the stages in the range from the final stages of obtaining BPA to obtain aromatic polycarbonate were carried out continuously by the method described above. Thus, satisfactory quality aromatic polycarbonate could be continuously produced for about six months.

Comparative Example 1

BPA and aromatic polycarbonate were continuously produced by using the same procedure as in Experimental Example 1, except that the storage tank capacity when receiving BPA in the BPA production step was changed to 50 L (Vb / Fb = 7). The resulting aromatic polycarbonate was characterized by a Mv value of 21,000 and an initial value of YI of 1.8.

However, after 2 days have elapsed since the initiation of the operation, the BPA storage tank became full, and this reduced productivity in the initial stages of the BPA production phase (stages preceding the storage tank). Therefore, the operation was regulated in such a way as to maintain a constant liquid level in the storage tank. After that, only the initial stages were stopped. As a result, the liquid level in the storage tank rapidly decreased, and after about 4 hours the tank became empty, which made it necessary to stop the subsequent stages and all stages of obtaining MS.

Comparative experimental example 2

BPA was continuously obtained in comparative experimental example 1, in which the performance in the initial stages of obtaining the BPA (stages preceding the storage tank) was controlled so as to maintain a constant liquid level in the storage tank. The obtained BPA was cooled, and then granulated and these granules were temporarily stored in a newly installed hopper for powdered BPA (capacity 1 m ³ ). After that, when the granules were supplied and dissolved in a solution containing DPC using a powder mass feeder, PC was continuously obtained by the method described above. As long as the BPA was in the powder hopper, the temporary cessation of the steps in the production of the BPA did not constitute any problem in terms of productivity in the production of MS. However, this method turned out to be disadvantageous in terms of thermal efficiency, since it was necessary to temporarily cool the molten BPA in order to turn it into a powder form, and then conduct heating to dissolve. In addition to this, dusting occurred during the supply of PBA, which led to the problem of clogging of the gas line.

Comparative experimental example 3

BPA was continuously obtained at a capacity of 7.7 kg / hr in comparative experimental example 1, in which the productivity in the steps following the storage tank was slightly increased in order to maintain a constant level of liquid in the storage tank. The obtained BPA was individually stored in a newly installed tank, characterized by a capacity of 2 m ³ , where as a result of adjustment the internal temperature equal to 160 ° C was maintained. After that, as in comparative experimental example 1, BPA was supplied as a starting material for producing RS at a flow rate of 7.2 kg / h. The resulting PC was characterized by an initial value of YI 1.8. However, as the operation continued, the color tone began to clearly deteriorate. Holding the BPA alone in the molten state resulted in a significant deterioration in quality.

Experimental Example 3

The following is an experimental example in which the stage of obtaining BPA, the stage of obtaining DPC and the stage of obtaining RS were connected to each other, and the storage stages upon receipt of BPA, upon receipt of DPC and upon receipt of RS were included in these stages of preparation.

Getting BPA

Obtaining BPA was carried out by the same method as in experimental example 1.

Getting DPC

Reaction stage

A molten phenol having a temperature of 50 ° C., at a flow rate of 6.4 kg / h, was continuously fed into the first reactor together with phenol containing catalyst as a catalyst, obtained by dehydration of low boiling compounds discharged as distillate from the distillation column described below low boiling compounds. Simultaneously with such a supply, the molten phenol was heated to 150 ° C. Phosgene gas at a flow rate of 0.75 nm ³ / h was continuously fed into the first reactor with sufficient stirring. The reaction mixture, which flowed out of the first reactor and contained the phase of the gas / liquid mixture, was fed into the second reactor through a bypass pipe. With sufficient stirring, the contents of the second reactor were also adjusted to withstand temperatures of 150 ° C. The liquid reaction mixture was fed to a degassing column. In a degassing column at 160 ° C., countercurrent contacting was carried out using nitrogen gas in order to ensure that phenylchloroformate obtained as an intermediate compound and phenol were completely introduced into the reaction. The liquid reaction mixture, characterized by a diphenyl carbonate concentration of approximately 89% by weight, was continuously discharged from the bottom of the degassing column. Almost 100% of the supplied phosgene was converted to diphenyl carbonate. On the other hand, the exhaust gases resulting from the synthesis of diphenyl carbonate (the reaction gas discharged from the second DPC production reactor and the nitrogen-containing gas discharged from the degassing column) were mixed with each other, and then cooled to 10 ° C. The resulting condensate was returned to the second reactor, while for the hydrogen chloride obtained in the form of an uncondensed gas, neutralization was carried out under the action of an aqueous alkaline solution and release.

Flushing Stage

The resulting liquid reaction mixture, diphenyl carbonate recovered from the extraction / distillation column described below, and an aqueous solution of sodium hydroxide with a concentration of approximately 5 wt.% (Liquid obtained by mixing an aqueous solution of sodium hydroxide with a concentration of 25 wt.% And the aqueous phase extracted after the subsequent water washing step) was fed into a neutralization / mixing tank equipped with a Teflon lining. For the contents, stirring was carried out at 80 ° C. for approximately 10 minutes and an adjustment was made to maintain a pH value of 8.5. After neutralization, the organic phase was separated using sedimentation, and then transferred to a tank of water washing / stirring. On the other hand, the aqueous phase remaining after separation (which contains phenol and sodium chloride) was contacted with water vapor, as a result of which the phenol present was almost completely recovered as phenol-containing water. This water was supplied to a water wash / stir tank in a subsequent step. In an aqueous wash / stir tank, the organic phase was washed using warm water in an amount of approximately 30% by weight, based on the amount of organic phase. The aqueous phase (which was recycled to the neutralization / mixing tank) was isolated and a crude diphenyl carbonate (containing water, pyridine catalyst and phenol) was obtained.

Stage distillation of low boiling compounds

After that, "raw" diphenyl carbonate and an aqueous solution of sodium hydroxide with a concentration of 0.1 N. continuously fed to the middle plate of the distillation column of low boiling compounds at a flow rate of approximately 9 kg / hour and 15 ml / hour, respectively. As this distillation column of low-boiling compounds, a continuous distillation column was used, characterized by the number of theoretical plates equal to 8, which had an inner diameter of 100 mm and a height of 4.0 m, was equipped with a reflux apparatus on top, had a feed part in the middle and had a concentration section and a recovery section, each of which was packed with Sulzer Packing (manufactured by Sumitomo Heavy Industries, Ltd.). The distillation was carried out under conditions of a degree of evacuation of 20 torr, a temperature of the heat transfer oil of approximately 220 ° C, a column top temperature of 80-100 ° C, and a reflux ratio of 1 to distill compounds having a boiling point lower than the boiling point of diphenyl carbonate, then there is water, a pyridine catalyst, and unreacted phenol. After dehydration of the low boiling compounds, part of these compounds was withdrawn, and the rest was fed to the first phosgenation reactor. On the other hand, diphenyl carbonate was discharged from the bottom of the column at a capacity of approximately 7.8 kg / h. It was impossible to detect water in it (10 ppm or less), and levels of pyridine and phenol (1 ppm or less) and 50 ppm, respectively, could not be detected.

Stage distillation of high boiling compounds

In addition, this diphenyl carbonate (bottoms from the distillation column of low boiling compounds) was continuously fed into the distillation column of high boiling compounds. As this distillation column of high-boiling compounds, a continuous distillation column was used, characterized by the number of theoretical plates equal to 8, which had an inner diameter of 100 mm and a height of 4.0 m, was equipped with a reflux apparatus on top, had a feed part in the middle and had a concentration section and a recovery section, each of which was packed with Sulzer Packing (manufactured by Sumitomo Heavy Industries, Ltd.). The distillation was carried out under conditions of a degree of evacuation of 20 torr, a temperature of the heat transfer oil of approximately 240 ° C, a top temperature of the column of approximately 180 ° C, a reflux ratio of 0.5, and a proportion of distillate of approximately 90%. As a result, purified diphenyl carbonate was obtained through the top of the column at a capacity of approximately 7.1 kg / hr (7 L / hr), and high boiling compounds were withdrawn from the bottom of the column at a capacity of approximately 0.8 kg / hr. The purified diphenyl carbonate was a high purity product containing 80 ppm phenol. A certain amount (approximately 100 L) of this diphenyl carbonate was stored at 100 ° C in a tank made of SUS316 material, characterized by a capacity of 200 L (for which the value of Vd / Fd indicated in the description was 29), and then as a starting material to obtain RS, they were fed at a flow rate of 7 l / h.

Extraction / distillation step

In addition, the bottom residue withdrawn from the bottom of the distillation column of high boiling compounds was simultaneously fed to the recovery / distillation column to conduct continuous distillation under the following conditions. Diphenyl carbonate was recovered through the top of the column at a capacity of approximately 0.7 kg / h and recycled to a neutralization / mixing vessel, while the bottom residue was continuously discharged at a capacity of approximately 0.04 kg / h. Regarding the extraction / distillation conditions for the production of diphenyl carbonate, a continuous distillation column was used, characterized by the number of theoretical plates equal to 8, which had an inner diameter of 50 mm and a height of 3.0 m, was equipped with a reflux apparatus on top, and had a supply section in the middle source material and had a concentration section and a recovery section, each of which was packed with Sulzer Packing (manufactured by Sumitomo Heavy Industries, Ltd.). Distillation was carried out under conditions of a degree of evacuation of 20 torr, a temperature of the heat-transfer oil approximately equal to 240 ° C, a top temperature of the column of 180 ° C and a reflux ratio of 0.5. In the bottoms from the recovery / distillation column, alkyl substituted diphenyl carbonate derivatives and bromine substituted diphenyl carbonate derivatives were found in amounts of approximately 7000 ppm (wt.) And approximately 800 ppm, respectively.

Getting RS

Polymerization Stage

In an atmosphere of gaseous nitrogen, the bisphenol A obtained above and supplied at a flow rate of 7.2 kg / h was mixed in the melt at 130 ° C. with diphenyl carbonate supplied at a flow rate of 7.1 kg / h. This mixture was continuously fed through a feed pipe, heated to 130 ° C, into the first vertical stirred polymerization reactor, in which, as a result of adjustment, the temperature was kept at 210 ° C in a nitrogen atmosphere at normal pressure. The liquid level was kept constant by adjusting the degree of openness of the valve located on the polymer discharge line connected to the lower part of the tank, so as to result in an average residence time of 60 minutes. In addition, simultaneously with initiating the supply of a mixture of starting materials, cesium carbonate in the form of an aqueous solution began to be continuously supplied as a catalyst at a flow rate of 0.5 · 10 ^-6 mol per one mol of bisphenol A. After that, the liquid polymerization reaction mixture produced from the bottom of the tank, continuously fed sequentially to the second, third and fourth vertical polymerization reactors and the fifth horizontal polymerization reactor. During the course of the reaction, the liquid level in each tank was adjusted so as to result in an average residence time of 60 minutes, and at the same time phenol obtained as a by-product was distilled off. Each of the gases obtained by evaporation and discharged, respectively, from tanks in the range from the first to third polymerization reactors was condensed and liquefied using a multi-stage condenser, and part of the condensate was refluxed into the polymerization reactor under reflux conditions, and the rest was recovered and stored in reservoir for phenol by-product. On the other hand, each of the gases obtained by evaporation and discharged from the fourth and fifth polymerization reactors was cured using one of two freezing capacitors arranged in parallel. The resulting solid phase was melted by switching to another freezing capacitor and recovered and stored in the by-product phenol reservoir.

The polymerization conditions for each reaction vessel were as follows: a second polymerization reactor (210 ° C, 100 torr), a third polymerization reactor (240 ° C, 15 torr), a fourth polymerization reactor (260 ° C, 0.5 torr) and a fifth polymerization reactor (270 ° C, 0.5 torr). The system operated at a production rate of polycarbonate equal to 8.0 kg / h.

After that, the resulting polymer in the molten state was introduced into a twin-screw extruder (manufactured by Kobe Steel, Ltd.) and 5 ppm butyl p-toluenesulfonate was continuously added thereto based on the amount of polycarbonate. Butyl p-toluenesulfonate was in the form of a masterbatch obtained by dispersing the mother liquor in polycarbonate flakes using a mixer, and it was fed into the extruder under a nitrogen atmosphere using a mass feeder. The polymer was granulated. The polycarbonate thus obtained was characterized by an Mv of 21,000 and an initial YI of 1.7.

Molecular Weight (Mv)

To measure the specific viscosity (ηsp) with a Ubellode viscometer at a temperature of 20 ° C, a solution in methylene chloride was used, characterized by a polycarbonate (C) concentration of 0.6 g / dl. The molecular weight was a value calculated from the viscosity using the following two equations:

ηsp / С = [η] (1 + 0.28ηsp)

[η] = 1.23Χ10 ^-4 (Mv) ^0.83

Initial color tone (YI)

The polycarbonate resin was dried at 120 ° C for 6 hours in a nitrogen atmosphere, and then using a J-100 injection machine manufactured by The Japan Steel Works, Ltd., a piece was obtained from the injection molding method at 360 ° C, having a thickness of 3 mm. This piece was examined using an SC-1 instrument manufactured by Suga Test Instruments Co., Ltd. to obtain a YI value (the higher the YI value, the more PC will be colored).

The purification step of a phenol by-product

The phenol by-product recovered from the polymerization step at a capacity of approximately 6.3 kg / hr (6 l / hr) was stored in a certain amount (approximately 100 l) in a phenol by-product reservoir (reservoir made of SUS304 material) characterized by a capacity of 200 L; the tank showed a Vc / Fc value of 33), and then was subjected to the following distillation / purification. The resulting purified phenol as a starting material for DPC production was recycled. The deficiency was partially covered using commercial phenol.

The first distillation column was operated at 200 torr and a reflux ratio of 2, due to which the water present was distilled off together with a part of phenol. The bottom residue was fed to a second distillation column. The second distillation column was operated at 50 torr and a reflux ratio of 0.5, and purified phenol was obtained through the top of the column at a capacity of approximately 5.8 kg / h. This purified phenol was fed to the DPC production step through a purified phenol tank. On the other hand, a liquid phenolic mixture containing diphenyl carbonate, bisphenol A and oligomers in amounts of 67 wt.%, 7 wt.% And 4 wt.%, Respectively, was continuously discharged as bottoms.

The experiment described above was continuously performed for 400 hours. During the experiment, it became necessary to temporarily stop the stage of obtaining DPC due to the occurrence of a problem related to temperature control and the like. However, since they used the liquid stored in the storage tank, there was no need to shut down the entire system, and measures could be quickly taken to fix the problem. During the operation, a polycarbonate grade was obtained, characterized by an Mv value of 15,000, which resulted in temporary changes in the composition, which is a by-product of phenol, recovered from the polymerization reactor. However, the changes could be reduced in the storage tank, and the conditions for the operations at the next stage of purification of the phenol by-product could be smoothly changed.

Example 5

The invention will now be explained in detail in connection with the processing of the spent solution. Incidentally, the methods used to measure the average viscosity molecular weight (Mv) and the initial color tone (YI) are described herein above.

Experimental Example 1

Stage DPC

The stage of obtaining DPC was carried out in accordance with the flowchart shown in figure 1. Details were as follows.

Stage reaction upon receipt of DPC

During continuous feeding of molten PL and pyridine catalyst into the DPC 1 production reactor with stirring at 150 ° C., phosgene gas (CDC) was continuously supplied thereto. After that, the mixture was fed to the dehydrochlorination column 2. Gaseous hydrogen chloride (D1), obtained as a by-product from phosgenation, was cooled to 10 ° C. The resulting condensate was returned to the reactor, while for the gas remaining non-condensed, neutralization was carried out using an aqueous alkaline solution, and then thereafter. On the other hand, dehydrochlorinated liquid b containing DPC in an amount of approximately 91 wt.% Was continuously discharged from dehydrochlorination column 2.

DPC flushing step / DPC water flushing step

Hydrochlorinated liquid b was fed into the mixing tank 3, and then into the alkaline neutralization tank 4, equipped with a Teflon lining. In addition, an aqueous solution of sodium hydroxide with a concentration of approximately 5 wt.% Was supplied to the alkaline neutralization vessel 4. For the contents, stirring was carried out at 80 ° C. for approximately 10 minutes and an adjustment was made to maintain a pH value of 8.5. After neutralization, the organic phase was separated using sedimentation, and then transferred to a water washing vessel 5. In the water washing vessel 5, the organic phase was washed using warm water in an amount of approximately 30 wt.% Based on the amount of organic phase. The aqueous phase was separated and an aqueous wash was obtained, f, which was a crude DPC (containing 1 wt.% Water, 2 wt.% Pyridine, 8 wt.% PL and 89 wt.% DPC).

DPC distillation step / low boiling point distillation step

After that, the water-washed liquid, f, was continuously fed to the middle plate of the first distillation column PL 6 at a flow rate of approximately 30 kg / h. As this first distillation column PL 6, a continuous distillation column was used, characterized by the number of theoretical plates equal to 8, which had an internal diameter of 150 mm and a height of 4.0 m, was equipped with a reflux apparatus on top, had in its middle part for supplying the starting material, and had a concentration section and a recovery section, each of which was packed with Sulzer Packing (manufactured by Sumitomo Heavy Industries, Ltd.). The distillation was carried out under conditions of a degree of evacuation of 20 torr, a temperature of the heat transfer fluid of approximately 220 ° C, a column top temperature of 80-100 ° C, an average plate temperature of 160 ° C and a reflux ratio of 1 to distill a mixed gas F containing compounds characterized by a temperature boiling point lower than the boiling point of DPC, i.e. water, pyridine and PL. At a productivity of approximately 26 kg / h, the residue after the first distillation g was continuously discharged from the bottom of the column, which was a bottom residue containing DPC (water levels of 10 ppm (wt.) Or less; pyridine 1 ppm (wt.) or less; PL 50 ppm (wt.)).

DPC distillation step / High boiling point distillation step

In addition, this residue after the first distillation g was continuously fed to the second distillation column PL 7. As this second distillation column PL 7, a continuous distillation column was used, characterized by the number of theoretical plates equal to 8, which had an inner diameter of 200 mm and a height of 4.0 m, it was equipped with a reflux apparatus on top, had in its middle part for supplying the starting material and had a concentration section and an extraction section, each of which was filled with Sulzer Packing (manufactured by Sumi tomo Heavy Industries, Ltd.). Distillation was carried out under conditions of a degree of evacuation of 20 torr, a temperature of the heat-transfer oil of approximately 240 ° C, a top temperature of the column of approximately 180 ° C and a reflux ratio of 0.5. As a result, purified DPC was obtained through the top of the column at a capacity of approximately 23.5 kg / h, and the residue after distillation to obtain DPC (X1), which was a high boiling point compound (DPC containing alkyl substituted DPC derivatives and brominated substituted DPC derivatives in amounts equal to approximately 350 ppm (wt.) and approximately 40 ppm (wt.), respectively), was withdrawn from the bottom of the column at a capacity of approximately 2.5 kg / h. Purified DPC was a high purity product containing PL in an amount of 80 ppm (wt.).

Stage of obtaining RS

Stage polymerization upon receipt of RS

RS was obtained in accordance with the flowchart shown in FIG. 5, as follows. In a nitrogen gas atmosphere, the purified DPC obtained in the DPC preparation step and BPA were mixed in the melt at a ratio of 0.977 (wt.) Using a mixing vessel 21. This mixture was continuously fed through a pipe to supply the starting material, heated to 130 ° C, into the first vertical polymerization reactor 22, in which, as a result of adjustment, the temperature was kept at 210 ° C in a nitrogen atmosphere at ordinary pressure. The liquid level was kept constant by adjusting the degree of openness of the valve located on the polymer discharge line connected to the lower part of the tank, so as to result in an average residence time of 60 minutes. In addition, simultaneously with the initiation of the feed of the mixture of starting materials as a catalyst, cesium carbonate in the form of an aqueous solution began to be continuously fed at a flow rate of 0.5 · 10 ^-6 mol per one mol of BPA. After that, the liquid polymerization reaction mixture discharged from the lower part of the vessel was continuously fed sequentially to the second and third polymerization reactors and the fourth horizontal polymerization unit. During the reaction, the liquid level in each tank was adjusted so as to obtain an average residence time of 60 minutes, and at the same time, the PL obtained as a by-product was distilled off. The steam-converted ingredients in the production of RS p, discharged from containers in the range from the first to the third polymerization reactors, were condensed and liquefied using the appropriate multi-stage capacitors. A portion of each of the resulting condensates, boiling under reflux conditions, was fed to the polymerization reactor, and the remainder was recovered and stored in the reservoir for recovered PL 29 upon receipt of RS. On the other hand, the gases obtained by evaporation and discharged from the fourth polymerizer were solidified using one of two freezing capacitors arranged in parallel. The resulting solid phase was melted by switching to another freezing capacitor and removed and stored in the reservoir for the recovered PL 29 upon receipt of a PC (not shown).

The polymerization conditions for each reaction vessel were as follows: a first polymerization reactor (210 ° C., 100 torr), a second polymerization reactor (240 ° C., 15 torr), a third polymerization reactor (260 ° C., 0.5 torr) and a fourth polymerization agent (270 ° C, 0.5 torr).

The resulting polymer in the molten state was introduced into a twin-screw extruder (manufactured by Kobe Steel, Ltd .; worm diameter 0.046 m; L / D = 40.2) 32 and granulated while adding 5-hour butyl p-toluenesulfonate / million (wt.) when calculating the number of RS. Thus, the resulting MS was characterized by a viscosity average molecular weight (Mv) of 21,000 and an initial color tone (YI) of 1.7.

Stage distillation PL

The steam-converted ingredients were analyzed upon receipt of RS p, recovered in the polymerization step upon receipt of RS. As a result, 5.0 wt.% DPC, 0.5 wt.% BPA, 0.3 wt.% Oligomers and 0.2 wt.% Water were found.

The steam-converted ingredients in the production of RS p were continuously purified using the following two distillation columns (PL 30 first distillation column and PL 31 second distillation column). The first distillation column PL 30 was operated at 200 torr and a reflux ratio of 2, whereby the water present was distilled off together with part of PL as a low boiling point distillate in the production of PC (D6). The bottom residue was continuously fed to the second distillation column PL 31 as the residue of the first stage q. The second distillation column PL 31 was operated at 50 torr and a reflux ratio of 0.5, and purified PL was obtained through the top of the column. The distillation residue PL (X2) containing DPC, BPA and oligomers in amounts of 67 wt.%, 7 wt.% And 4 wt.%, Respectively, was continuously discharged as bottoms.

(An example in which the residue after distillation X2 at the stage of obtaining RS was fed to the stage of distillation at the stage of obtaining DPC)

The residue after distillation of PL (X2; containing 22 wt.% PL, 67 wt.% DPC, 7 wt.% BPA and 4 wt.% Oligomers) removed from the purification step, which is a by-product of PL at the above-described step for the preparation of PC, was fed to the first distillation column upon receipt of DPC 6 in the above-described step for producing DPC. Then, the residue after the first distillation g, which was the bottom residue from the first distillation column upon receipt of DPC 6, was fed to the second distillation column upon receipt of DPC 7. As a result, almost 100% PL contained in the first distillation column upon receipt of DPC 6 was recovered in the remainder after distillation PL (X2), and about half of the DPC was recovered through the top of the second distillation column to obtain DPC 7. Thus, the effective ingredients could be efficiently recovered simply by sending the residue after distillation of PL (X2) for recycling to the existing indicated steps.

DPC and PC were obtained according to the methods described above, while carrying out the above operation. As a result of the resulting DPC and PC, the quality problem was completely unusual.

Experimental Example 2

Stage DPC

The stage of obtaining DPC was carried out in accordance with the flowchart shown in figure 1. Details were as follows.

Extraction / distillation step

The distillation residue upon receipt of DPC (X1) discharged from the distillation stage of high-boiling compounds at the stage on which the DPC was obtained in experimental example 1 was fed to the recovery / distillation column to obtain DPC 8 and continuous distillation was carried out under the following conditions to recover as distillate through the top of the column recovered fluid containing DPC, d. The recovered distillate was recycled to the mixing vessel in the DPC preparation step to achieve an improved yield. On the other hand, the residue after extraction / distillation upon receipt of DPC (X1 '), which was a high boiling point compound (DPC containing alkyl substituted DPC derivatives and brominated substituted DPC derivatives in amounts of approximately 7000 ppm (wt.) And approximately 800 hours / million (wt.), respectively), continuously discharged as the bottom residue from the extraction / distillation column upon receipt of the DPC.

For extraction / distillation in the preparation of DPC, a continuous distillation column was used, characterized by the number of theoretical plates equal to 8, which had an internal diameter of 100 mm and a height of 3.0 m, was equipped with a reflux apparatus on top, had a feed part in the middle and had a concentration section and a recovery section, each of which was packed with Sulzer Packing (manufactured by Sumitomo Heavy Industries, Ltd.). Distillation was carried out under conditions of a degree of evacuation of 20 torr, a temperature of the heat-transfer oil approximately equal to 240 ° C, a top temperature of the column of 180 ° C and a reflux ratio of 0.5.

Other operations were carried out by the same method as in experimental example 1. Thus, in the form of a high-purity product, purified DPC (containing PL in an amount equal to 80 ppm (wt.)) Was obtained and PC was synthesized.

(An example in which the residue after distillation (X2) at the stage of obtaining RS was fed to the stage of extraction / distillation at the stage of obtaining DPC)

The residue after distillation of PL (X2; containing 22 wt.% PL, 67 wt.% DPC, 7 wt.% BPA and 4 wt.% Oligomers), withdrawn from the distillation stage PL at the above stage of obtaining RS, was fed to the recovery column / distillation upon receipt of DPC 8 at the stage of obtaining DPC. As a result, almost 100% of the PL contained in the residue after distillation and approximately 80% by weight of the DPC contained in the residue were recovered through the top of the recovery / distillation column. Thus, the effective ingredients could be efficiently recovered simply by sending the residue after distillation of PL X2 for recycling to the existing indicated steps.

DPC and PC were obtained according to the methods described above, while carrying out the above operation. As a result of the resulting DPC and PC, the quality problem was completely unusual.

Experimental Example 3

The stage of obtaining BPA

The stage of obtaining BPA was carried out in accordance with the schemes of technological processes shown in figure 2-4. In a 60-liter thermostatic BPA reactor equipped with a thermostat, a packing in the form of an acidic cation exchange resin in the form of sulfonic acid (trade name DIAION SK-104, manufactured by Mitsubishi Chemical Corp.), in which 15% of sulfo groups was neutralized, was placed action of 4-pyridinethanethiol. A liquid mixture of PL and acetone with a molar ratio of 10: 1 was introduced into this BPA reactor at a temperature of 80 ° C and a flow rate of 68.2 kg / hr, ensuring the reaction between them. The degree of conversion of acetone was 80%. After the low boiling compounds (unreacted acetone, water, and part of PL) were removed at a rate of 5.1 kg / h, the reaction mixture was cooled to 50 ° C, thereby precipitating adduct crystals. This mixture was filtered to separate it into adduct crystals and mother liquor. The productivity upon receipt was 16.5 kg / h and 46.5 kg / h, respectively. Ten weight percent of this mother liquor was fed to the mother liquor processing stage, while circulation was carried out for the remaining mother liquor as part of the starting material introduced into the synthesis reactor.

The adduct crystals thus obtained were redissolved in phenol supplied at a flow rate of 27.2 kg / h. The resulting solution was cooled to 50 ° C, achieving crystal precipitation, and then filtered to separate adduct crystals (11.3 kg / h) from the mother liquor (32.5 kg / h). The isolated crystals were heated to 180 ° C. under reduced pressure of 0.3 mm Hg to remove PL. Thus, with a capacity of 7.7 kg / h, BPA was obtained, characterized by a degree of purity of 99.95% or more.

On the other hand, the mother liquor supplied to the mother liquor processing step was processed using the PL 13 evaporator shown in FIG. 4 to distill part of the PL and concentrate the mother liquor. After that, 0.1 wt.% Sodium hydroxide was added to the mother liquor, and then the mother liquor was introduced into the bottom of the residue processing reactor 14, which acts as a decomposition / distillation column, in which, as a result of adjustment, a reduced pressure of 50 mmHg and a temperature of 210 ° C. This reactor was operated under such conditions in order to maintain a constant liquid level in the lower part (residence time 1 hour), and the bottom residue in the decomposition / distillation column was removed from the system at a capacity of 0.5 kg / hour. In addition, the distillate discharged through the top of residue processing reactor 14 was mixed with PL, and this mixture, at a flow rate of 4.2 kg / h, was introduced into a flow-type regeneration reactor 15 equipped with a 4 liter packing of acid cation exchange resin in the form sulfonic acid (trade name DIAION SK-104, manufactured by Mitsubishi Chemical Corp.). The reaction for the mixture was carried out at 80 ° C. For the obtained liquid reaction mixture, circulation was carried out with feeding to the BPA production reactor used in the initial stage.

Acetone (3.6 kg / h) and PL (18.5 kg / h) were additionally fed to the BPA production reactor in amounts corresponding to the quantities withdrawn from the system and the amount of BPA obtained. Thus, the synthesis reaction was carried out continuously, and the whole system functioned in the continuous production of BPA.

(An example in which the distillation residue upon receipt of DPC (X1) in the DPC production step and the residue after distillation PL (X2) at the RS production stage were fed to the mother liquor processing stage at the BPA production stage)

The distillation residue upon receipt of DPC (X1; containing approximately 350 ppm (wt.) Alkyl substituted DPC derivatives, approximately 40 ppm (wt.) Bromo substituted DPC and DPC derivatives constituting the residue) discharged from the DPC production step, and the remainder after distillation of PL (X2; containing 22 wt.% PL, 67 wt.% DPC, 7 wt.% BPA and 4 wt.% oligomers), withdrawn from the purification step, which is a by-product of PL at the preparation step of PC, was fed at a rate equal to 0.11 kg / h and 0.15 kg / h, respectively, at the stage of processing the mother liquor (stage (g)) at the floor cheniya BPA. During this operation, the residue processing reactor 14 operated under such conditions as to maintain a constant liquid level in the lower part (residence time 1 hour) and to discharge the lower product from the system at a capacity of 0.6 kg / hour.

As a result, almost 100% of PL contained in these residues from the distillation and decomposition products of BPA was recovered through the top of the residue processing reactor at the mother liquor processing stage. Thus, the effective ingredients could be efficiently recovered simply by sending the residues after distillation for recycling to the existing indicated stage.

BPA, DPC, and PC were obtained by the methods described above, while performing the above operation. As a result of the obtained BPA, DPC and PC, the quality problem was completely unusual.

Experimental Example 4

(An example in which the residue after extraction / distillation upon receipt of DPC (X1 ') at the stage of obtaining DPC and the residue after distillation PL (X2) at the stage of obtaining RS was fed to the mother liquor processing stage at the BPA production stage)

The residue after extraction / distillation upon receipt of DPC (X1 '; containing approximately 7000 ppm (wt.) Alkyl substituted DPC derivatives, approximately 800 ppm (wt.) Brominated derivatives DPC and DPC, comprising the residue) discharged from the DPC production step , and the residue after distillation of PL (X2; containing 22 wt.% PL, 67 wt.% DPC, 7 wt.% BPA and 4 wt.% oligomers) removed from the purification step, which is a by-product of PL at the PC production step, was fed at costs equal to 0.11 kg / h and 0.15 kg / h, respectively, at the stage of processing the mother liquor (stage (g)) a production step of BPA. During this operation, the residue processing reactor 14 operated under such conditions as to maintain a constant liquid level in the lower part (residence time 1 hour) and to discharge the lower product from the system at a capacity of 0.6 kg / hour.

As a result, almost 100% of PL contained in these residues from the distillation and decomposition products of BPA was recovered through the top of the residue processing reactor at the mother liquor processing stage. Thus, the effective ingredients could be efficiently recovered simply by sending the residues after distillation for recycling to the existing indicated stage.

BPA, DPC, and PC were obtained by the methods described above, while performing the above operation. As a result of the obtained BPA, DPC and PC, the quality problem was completely unusual.

Experimental Example 5

(An example in which the residue after distillation PL (X2) in the PC production step was fed to the extraction / distillation step in the DPC production step, and the residue after extraction / distillation in the production of DPC (X1 ') was fed to the mother liquor processing step in the BPA production step )

The residue after distillation of PL (X2; containing 22 wt.% PL, 67 wt.% DPC, 7 wt.% BPA and 4 wt.% Oligomers) discharged from the purification stage, which is a by-product of PL at the stage of obtaining RS, was fed to the recovery column distillation upon receipt of DPC 8 at the stage of obtaining DPC. An effective ingredient discharged as a distillate from the recovery / distillation column upon receipt of DPC 8 was recycled to the washing step of the DPC production stage, and the residue after extraction / distillation upon receipt of DPC (X1 ′) as the bottom residue from the extraction / distillation column upon receipt of DPC 8 was applied to the stage of processing the mother liquor (stage (g)) at the stage of obtaining BPA. An effective ingredient recovered at this processing stage was used as a starting material for synthesis in the BPA production step. BPA, DPC, and MS were continuously obtained for 400 hours while performing the above operation. As a result of the obtained BPA, DPC and PC, the quality problem was completely unusual. High boiling waste could be integrated into one stream discharged from the mother liquor processing stage to the BPA production stage. The amount of waste was significantly reduced, and the yield was significantly improved.

Despite the fact that the invention has been described in detail and using references to specific options for its implementation, it should be obvious to a person skilled in the art that without deviating from the scope and essence of the invention, various changes and modifications can be made.

This application basically has a Japanese patent application filed on August 21, 2003 (application No. 2003-297844), a Japanese patent application filed August 21, 2003 (application No. 2003-297719), a Japanese patent application filed on August 21, 2003 ( Application No. 2003-297832), Japanese Patent Application filed November 12, 2003 (Application No. 2003-382667), Japanese Patent Application filed November 12, 2003 (Application No. 2003-382773) and Japanese Patent Application filed November 12, 2003 (application No. 2003-382646), the contents of which in its entirety are included in this document for reference.

Industrial Applicability

According to the invention, the level of water in the phenol by-product is limited to a value in a predetermined range. For this reason, even if this phenol is a by-product and is used as part of the starting material used in the production of diphenyl carbonate or in the production of bisphenol A, the production efficiency will decrease slightly and remain almost unchanged.

In addition, the impurities contained in the phenol by-product recovered at an early stage of polymerization in the aromatic polycarbonate production step are the starting material used in the diphenyl carbonate production step and the reaction products obtained in the step. Therefore, this phenol by-product that contains these impurities can be used without purification as at least part of the phenol used in the diphenyl carbonate production step.

On the other hand, impurities containing phenol in the by-product recovered at the late stage of polymerization in the aromatic polycarbonate production step are hydrolyzed in the bisphenol A production step and become the starting material and reaction products for this step. In addition, the phenol which is a by-product does not contain almost any alcohols and the like, which would cause a deterioration in the catalytic activity in the production of bisphenol A. Therefore, this phenol by-product, which contains these impurities, can be used without purification the quality of at least part of the phenol used in the production of bisphenol A.

In addition, as a result of the implementation of the integral variant of the stage of producing diphenyl carbonate, the stage of producing bisphenol A and the stage of obtaining aromatic polycarbonate, it becomes possible to use commercial phenol as a starting material for the production of diphenyl carbonate and to use the distillate ingredients obtained in the polymerization stage at the stage of producing aromatic polycarbonate, as the starting material for the production of bisphenol A.

In addition, if before and / or after the distillation stage of PL is carried out, a storage step is carried out upon receipt of MS, in which liquefied steam-converted ingredients are stored upon receipt of MS, exposed to the distillation step PL, and / or phenol recovered in the distillation step is a by-product PL, if, after carrying out the distillation step in the preparation of DPC, carry out the storage step in the production of DPC, which stores the diphenyl carbonate obtained in the distillation step in the production of DPC, and / or if in the interval between the crystallization step isolation of BPA and the polymerization step in the preparation of RS to carry out the storage step in the production of BPA, in which a mixture of bisphenol A and phenol is stored, then the quality of the compound obtained in each step can be maintained in a certain range, and later stages can be carried out continuously independently from previous stages.

In addition, if the residue after distillation of PL, the residue after distillation upon receipt of DPC and / or the residue after extraction / distillation upon receipt of DPC is fed to the indicated step, then the effective ingredients contained in these residues can be used completely. Consequently, cumulative efficiency can be improved, and the environmental burden can be reduced.

In addition, if the vacuum pipe that connects the condenser to the vacuum device is inclined, adjust so that the total height of the parts rising upward opposite the slope is 1 m or less, then the amount of liquid and solid substances remaining in rising parts can be minimized, and it will be possible to prevent the complete clogging of the pipeline or the appearance of excessively large pressure losses in it.

Claims (43)

1. A method of producing aromatic polycarbonate, which includes a step for producing diphenyl carbonate, in which phenol and at least one carbonyl compound are used as starting materials for the production of diphenyl carbonate, and / or a step for producing bisphenol A, in which phenol and acetone are used as starting materials for the production of bisphenol A; and a step for producing aromatic polycarbonate, in which diphenyl carbonate and bisphenol A are used as starting materials in the production of aromatic polycarbonate as a result of the polymerization stage of aromatic carbonate, and the phenol by-product is recovered, characterized in that the amount of water contained in the phenol by-product recovered in the aromatic polycarbonate production step is set at 0.2 wt% or less, and this phenol is used as a starting material in the diphenyl carbonate production step and / or the bisphenol production step A, and the carbonyl compound is phosgene, carbon monoxide or dialkyl carbonate. 2. The method of producing aromatic polycarbonate according to claim 1, characterized in that the step for producing diphenyl carbonate is a step comprising a step for reacting diphenyl carbonate and a step for distilling diphenyl carbonate. 3. The method of producing aromatic polycarbonate according to claim 1, characterized in that the step for producing bisphenol A comprises a step for reacting bisphenol A, a step for removing low boiling compounds of bisphenol A and a step for crystallizing / isolating bisphenol A, and further includes a step for low-boiling distillate of bisphenol A, obtained at the stage of removal of low-boiling compounds of bisphenol A, is subjected to the stage of separation of a mixture of bisphenol A / water to extract phenol. 4. The method for producing aromatic polycarbonate according to claim 1, characterized in that the step for recovering a phenol by-product in the step for producing aromatic polycarbonate is a step in which the vaporized ingredients of the aromatic carbonate obtained in the polymerization stage of the aromatic carbonate are liquefied and subjected to the phenol distillation step removing the low boiling point aromatic carbonate distillate from the vaporized ingredients, and thereby recovering a phenol by-product. 5. The method of producing aromatic polycarbonate according to claim 4, characterized in that the concentration of phenol in the low boiling point distillate of aromatic polycarbonate removed in the phenol distillation step is in the range of 50-99.8 wt.%. 6. The method for producing aromatic polycarbonate according to claim 4, the step of producing diphenyl carbonate includes the step of washing diphenyl carbonate between the step of reacting diphenyl carbonate and the step of distilling diphenyl carbonate, and the low boiling point aromatic carbonate distillate obtained in the phenol distillation step is fed to the diphenyl carbonate washing step. 7. The method for producing aromatic polycarbonate according to claim 4, characterized in that the low-boiling aromatic carbonate distillate obtained in the phenol distillation step is fed to the separation step of the bisphenol A / water mixture. 8. The method of producing aromatic polycarbonate according to claim 1, characterized in that the content of hydroxyacetate in phenol used as a starting material in the production of bisphenol A is below 10 ppm wt. 9. The method of producing aromatic polycarbonate according to claim 3, where the acid catalyst used in the step of reacting bisphenol A is a cation exchange resin with a sulfonic acid, modified with a compound having a mercapto group. 10. The method of producing aromatic polycarbonate according to claim 4, characterized in that before and / or after the phenol distillation step, the aromatic carbonate storage step is carried out, where liquefied vaporized aromatic carbonate ingredients are stored, which are then subjected to the phenol distillation step, and / or a by-product phenol recovered in the phenol distillation step and an aromatic carbonate storage tank with a capacity meeting the requirement presented is used for the storage stage of aromatic carbonate the following expression (1)

(where Vc is the capacity (m ³ ) of the aromatic carbonate storage tank, and Fc is the flow rate (m ³ / h) of liquefied vaporized aromatic carbonate ingredients or a phenol by-product). 11. The method of producing aromatic polycarbonate according to claim 2, characterized in that after carrying out the diphenyl carbonate distillation step, the diphenyl carbonate storage step is carried out, which stores the diphenyl carbonate obtained in the diphenyl carbonate distillation step, and a diphenyl carbonate storage tank with a capacity satisfying the capacity is used for the diphenyl carbonate storage step the requirement represented by the following expression (2)

(where Vd is the capacity (m ³ ) of the diphenyl carbonate storage tank, and Fd is the consumption (m ³ / h) of diphenyl carbonate). 12. The method of producing aromatic polycarbonate according to claim 3, characterized in that the storage step of bisphenol A, which stores a mixture of bisphenol A and phenol, is carried out between the crystallization / recovery of bisphenol A and the polymerization stage of aromatic carbonate. 13. The method of producing aromatic polycarbonate according to claim 12, characterized in that for the storage stage of bisphenol A, a reservoir for storing bisphenol A is used with a capacity that meets the requirement represented by the following expression (3)

(where Vb is the capacity (m ³ ) of the bisphenol A storage tank, and Fb is the flow rate (m ³ / h) of bisphenol A supplied to the aromatic carbonate polymerization step). 14. The method of producing aromatic polycarbonate according to claim 12, characterized in that the bisphenol A / phenol mixture intended for storage at the storage stage of bisphenol A is in the form of crystals of the adduct of bisphenol A with phenol; a suspension containing crystals of the adduct of bisphenol A with phenol; or a liquid mixture of bisphenol A and phenol. 15. The method of producing aromatic polycarbonate according to item 12, wherein the stage of neutralization is carried out between the stage of crystallization of bisphenol A and the stage of polymerization of aromatic carbonate or before carrying out these stages. 16. The method of producing aromatic polycarbonate according to claim 3, characterized in that the stages in the range from the interaction stage of bisphenol A to the crystallization stage of bisphenol A are carried out periodically, and the polymerization stage of aromatic carbonate is carried out continuously. 17. The method of producing aromatic polycarbonate according to claim 4, characterized in that the residue after the distillation of phenol obtained in the stage of distillation of phenol is fed to the stage of distillation of diphenyl carbonate. 18. The method for producing aromatic polycarbonate according to claim 1, characterized in that the step for producing diphenyl carbonate includes a step for recovering / distilling diphenyl carbonate, in which diphenyl carbonate is recovered from the residue after distillation of diphenyl carbonate, and the residue after distillation of phenol obtained on phenol distillation steps, fed to the diphenyl carbonate distillation step and / or to the diphenyl carbonate recovery / distillation step. 19. The method of producing aromatic polycarbonate according to claim 1, characterized in that the step for producing bisphenol A comprises a stage in which part or all of the mother liquor obtained in the crystallization / isolation step of bisphenol A is fed to the step for processing the mother liquor of bisphenol A to reduce the amount by-products in the mother liquor, and then this mother liquor is used as part or all of the phenol used as starting material for the production of bisphenol A, and the residue after distillation of phenol obtained obtained at the stage of distillation of phenol, and / or the residue after distillation of diphenyl carbonate, obtained at the stage of distillation of diphenyl carbonate, is fed to the stage of processing the mother liquor of bisphenol A at the stage of producing bisphenol A. 20. The method for producing aromatic polycarbonate according to claim 4, characterized in that the phenol distillation residue obtained in the phenol distillation step and / or at least one of the residue after the distillation of diphenyl carbonate obtained in the diphenyl carbonate distillation step and the residue after recovery / distillation of diphenyl carbonate obtained in the stage of extraction / distillation of diphenyl carbonate, served on the stage of processing the mother liquor of bisphenol A at the stage of obtaining bisphenol A. 21. The method of producing aromatic polycarbonate according to claim 4, characterized in that the phenol distillation residue obtained in the phenol distillation step is fed to the diphenyl carbonate distillation step, and then the distillation residue obtained in the phenol distillation step is fed to the mother liquor treatment stage bisphenol A. 22. The method of producing aromatic polycarbonate according to claim 4, characterized in that the phenol distillation residue obtained in the phenol distillation step is fed to the diphenyl carbonate distillation step and / or the diphenyl carbonate extraction / distillation step, and then the residue after the distillation of diphenyl carbonate and / or the remainder after extraction / distillation of diphenyl carbonate, obtained at the stage of distillation of diphenyl carbonate, is fed to the stage of processing the mother liquor of bisphenol A. 23. The method of producing aromatic polycarbonate according to claim 19, characterized in that the step of treating the mother liquor of bisphenol A comprises adding a basic substance to part or all of the mother liquor, heating the mixture to produce phenol and phenol derivatives, and then reacting phenol and phenol derivatives with acid catalyst or alkaline catalyst, thus obtaining bisphenol A. 24. The method of producing aromatic polycarbonate according to item 23, wherein the main substance is sodium hydroxide or potassium hydroxide. 25. The method of producing aromatic polycarbonate according to claim 2, characterized in that the distillation column at the stage of distillation of diphenyl carbonate is equipped with a condenser for condensing the distillate, a vacuum device to reduce the pressure in the system and a vacuum pipe that connects the condenser to the vacuum device, and the vacuum pipe is inclined downward from the side of the condenser to the side of the vacuum device, and the total height of the parts rising upward from the side of the condenser to the side of the vacuum device is 1 m or less. 26. The method of producing aromatic polycarbonate according to claim 4, characterized in that the polymerizer used in the liquefaction stage of the vaporized ingredients of the aromatic polycarbonate, at the stage of polymerization of the aromatic polycarbonate, is equipped with a condenser for condensing the evaporated ingredients of the PC obtained as a distillate, with a vacuum device to reduce the pressure in the polymerization system and the vacuum pipe that connects the capacitor to the vacuum device, and the vacuum pipe is tilted down t of the capacitor side to the side of the vacuum device, and the total height of the parts rising upward from the side of the capacitor to the side of the vacuum device is 1 m or less. 27. The method of producing aromatic polycarbonate according to claim 4, characterized in that the distillation column at the stage of phenol distillation is equipped with a condenser to condense the distillate, a vacuum device to reduce the pressure in the system and a vacuum pipe that connects the condenser to the vacuum device, and the vacuum pipe is inclined downward from the side of the condenser to the side of the vacuum device, and the total height of the parts rising upward from the side of the condenser to the side of the vacuum device is 1 m or less. 28. The method of producing aromatic polycarbonate according to any one of paragraphs.25-27, characterized in that the vacuum pipe is provided with at least one drainage hole in that part, which is located on the side of the vacuum device. 29. The method of producing aromatic polycarbonate according to any one of paragraphs.25-27, characterized in that the vacuum pipe in that part, which is located on the side of the condenser, is provided with a feed hole through which heated fluid can be supplied. 30. The method of producing aromatic polycarbonate according to clause 29, wherein the heated fluid is supplied through the feed hole, thereby cleaning the vacuum pipe. 31. The method of producing aromatic polycarbonate according to clause 29, wherein the heated fluid includes at least one member of a series including water vapor, phenol and nitrogen. 32. The method of producing aromatic polycarbonate according to claim 1, characterized in that the phenol used as a starting material in the diphenyl carbonate production step is phenol containing cresol and / or xylenol in an amount of 20-1000 ppm, and phenol, obtained at the stage of polymerization at the stage of obtaining aromatic polycarbonate, is used as at least a part of phenol used as starting material in the stage of producing bisphenol A. 33. The method of producing aromatic polycarbonate according to p, characterized in that the content of cresol and / or xylenol in phenol used as starting material in the production of bisphenol A is less than 20 ppm. 34. The method of producing aromatic polycarbonate according to p, characterized in that the phenol obtained in the polymerization stage of the stage of production of aromatic polycarbonate is used as at least part of the phenol used as starting material in the stage of producing bisphenol A, after conducting the stage of removing water. 35. The method of producing aromatic polycarbonate according to clause 34, wherein the step of producing bisphenol A comprises a step of reacting bisphenol A, a step of removing low boiling compounds of bisphenol A, and a crystallization / recovery step of bisphenol A, and further comprising a step in which the low boiling distillate of bisphenol A, obtained at the stage of removal of low-boiling compounds of bisphenol A, subjected to the stage of separation of a mixture of bisphenol A / water to extract phenol, and the water removal step is a water evolution step in the bisphenol A production step. 36. The method of producing aromatic polycarbonate according to clause 34, wherein the stage of water removal is followed by the stage of separation of the mixture of bisphenol A / high-boiling compounds, which emit ingredients having a boiling point higher than phenol. 37. The method of producing aromatic polycarbonate according to clause 36, wherein the step for producing bisphenol A comprises a step in which part or all of the mother liquor obtained in the crystallization / recovery step of bisphenol A is fed to the step for treating the mother liquor of bisphenol A to reduce the amount by-products in the mother liquor, and then this mother liquor is used as part or all of the phenol used as starting material for the production of bisphenol A, and ingredients having a boiling point I, higher than phenol, which are obtained at the stage of removal of bisphenol A / high-boiling compounds, served at the stage of processing the mother liquor of bisphenol A. 38. The method of producing aromatic polycarbonate according to claim 1, characterized in that 50-95 wt.% Phenol obtained as a by-product in the stage of production of aromatic polycarbonate, is used as at least part of phenol used in the stage of obtaining diphenyl carbonate and 50-5 wt.% it is used as at least part of the starting material for the stage of obtaining bisphenol A. 39. The method of producing aromatic polycarbonate according to § 38, characterized in that 50-70 wt.% Phenol obtained as a by-product in the stage of production of aromatic polycarbonate, is used as at least part of phenol used in the stage of obtaining diphenyl carbonate and 50-30 wt.% it is used as at least part of the starting material for the stage of obtaining bisphenol A. 40. The method of producing aromatic polycarbonate according to claim 1, characterized in that the polymerization stage at the stage of aromatic polycarbonate production comprises at least three polymerization reactors, and phenol by-product extracted from the first reactor or from the first and second reactors among the reactors polymerization is used as at least part of the phenol used in the diphenyl carbonate production step, and the phenol by-product recovered from the second and subsequent polymerization reactors, or from the third and subsequent polymerization reactors, are used as at least part of the phenol used in the bisphenol A production step. 41. The method for producing aromatic polycarbonate according to claim 38 or 40, wherein the phenol by-product used in the diphenyl carbonate production step contains up to 1.0 wt.% High boiling compounds which have a boiling point higher than diphenyl carbonate. 42. The method of producing aromatic polycarbonate according to § 38 or 40, where one or more polymerization reactors from which the phenol by-product used in the diphenyl carbonate production step is obtained includes a reflux apparatus for refluxing the vaporized ingredients. 43. The method of producing aromatic polycarbonate according to § 38 or 40, where if the carbonyl compound is a dialkyl carbonate and / or alkyl aryl carbonate, and phenol obtained as a by-product in the stage of production of aromatic polycarbonate is used as part of the starting material in the stage of producing bisphenol A, the phenol used as starting material contains dialkyl carbonate, alkyl aryl carbonate and alkyl alcohol derived from dialkyl carbonate and / or alkyl aryl carbonate in an amount of 20 ppm wt. or less.

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