JP2024130529A - Method for producing bisphenol and method for producing polycarbonate resin - Google Patents

Abstract

To provide a method for producing bisphenol which improves mixing defects of a reaction for producing bisphenol, and enables production in an industrial production scale.MEANS FOR SOLVING THE PROBLEM: A method for producing bisphenol that is produced by condensing ketone or aldehyde and aromatic alcohol in the presence of an acid catalyst includes: Step (A) of mixing the aromatic alcohol with the acid catalyst to obtain a mixed liquid; Step (B) of dripping and supplying the ketone or aldehyde to the mixed liquid A as a drip and supply liquid, or dripping and supplying the mixed liquid A to the ketone or aldehyde as a drip and supply liquid, and stopping the supply when a dripping rate of the drop and supply liquid becomes 80% or less; and Step (C) of precipitating crystal of bisphenol.SELECTED DRAWING: None

Description

The present invention relates to a method for producing a bisphenol from an aromatic alcohol and a ketone or an aldehyde, and also to a method for producing a polycarbonate resin using the obtained bisphenol.
The bisphenol produced by the method of the present invention is useful for polycarbonate resins, epoxy resins,
It is useful as a raw material for resins such as aromatic polyester resins, as a hardener, a color developer, a discoloration inhibitor, and as an additive for other bactericides, antibacterial agents, and antifungal agents.

Bisphenols are useful as raw materials for polymeric materials such as polycarbonate resins, epoxy resins, and aromatic polyester resins. Representative bisphenols include, for example, 2
, 2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3-
Methylphenyl)propane and the like are known (Patent Document 1).

JP 62-138443 A JP 2008-214248 A Japanese Patent Application Publication No. 11-49714 Patent Publication No. 2021-147367 Japanese Unexamined Patent Publication No. 60-038335

Bisphenols are used in a wide range of applications as raw materials for various resins such as polycarbonate resins, and their applications are expected to continue to expand in the future. As such, there is a demand to increase the reaction scale and produce bisphenols more efficiently on an industrial production scale.

However, the methods for producing bisphenol described in Patent Documents 2 and 3 have not been sufficiently studied from the industrial viewpoint of scaling up the production amount.

In the synthesis reaction of bisphenol, the product bisphenol is generally precipitated as the reaction proceeds, and the reaction proceeds in a slurry state. In such a reaction system, the amount of solid bisphenol increases as the reaction proceeds, and the concentration of solid bisphenol in the reaction liquid (slurry concentration) becomes high, resulting in a highly viscous reaction liquid, which may cause poor mixing.

For example, in the bisphenol production methods described in Patent Documents 2 and 3, as examples of actual bisphenol production, it is described that bisphenol was produced in a small-scale reaction tank of 10 liters or less.
In general, in a small-scale reaction tank of 10 liters or less, it is easy to freely combine the reaction tank and the stirring blade, so that even in a reaction liquid with high viscosity, it is easy to maintain the stirring efficiency by reducing the clearance between the reaction tank and the stirring blade. Therefore, even in a reaction system in which bisphenol precipitates as the reaction proceeds, it tends to be easy to avoid deterioration of the mixability of the reaction liquid.

In contrast, in industrial-scale bisphenol production methods, production is generally performed using a reaction tank of cubic meters (1000 liters) or more. These facilities tend to have a general-purpose configuration, and the shape of the stirring blades and the clearance between the reaction tank and the stirring blades are not necessarily designed to be suitable for the production of bisphenol. Therefore, when the reaction for producing bisphenol is carried out and the viscosity of the reaction solution increases due to the precipitation of bisphenol, there is a concern that solid bisphenol will accumulate locally in the reaction tank, resulting in poor mixing.
Therefore, it cannot be said that the methods for producing bisphenol disclosed in Patent Documents 2 and 3 fully consider problems that may arise when the production amount is scaled up to an industrial scale.

In the method described in Example 1 of Patent Document 4, when the bisphenol production reaction is carried out on a large scale, when bisphenol crystals precipitate and the reaction liquid becomes slurried, the slurry may locally accumulate and cause problems such as poor mixing. As a result, the color of the obtained bisphenol may deteriorate and the amount of by-products may increase, leading to a decrease in the quality of the bisphenol.

The cause of the poor mixing of the reaction liquid here is an increase in the viscosity of the reaction liquid, and it is presumed that one of the causes of the increase in viscosity of the reaction liquid is the mixing of an oil phase such as an aromatic alcohol or aromatic hydrocarbon with an aqueous phase such as an acid catalyst or by-product water to form an emulsion, resulting in an increase in apparent viscosity.

In addition, in the method described in Example 1 of Patent Document 5, when it is carried out on a large scale,
It is presumed that the selectivity for bisphenol deteriorates because the produced bisphenol is in an environment where it is constantly in contact with the hydrochloric acid and hydrogen chloride gas of the acid catalyst in the reaction liquid and therefore the bisphenol can easily decompose.
Under these circumstances, in the field of bisphenol production, there has been a demand for a method for improving the mixability of a reaction solution under reaction conditions that enable synthesis of bisphenol with high selectivity regardless of the production scale.

The present invention has been made in view of the above circumstances, and aims to realize industrial-scale production by improving stirring efficiency by reducing the viscosity of a reaction solution in a reaction crystallization system in which crystals are precipitated during a reaction. Another aim of the present invention is to provide a method for producing a polycarbonate resin using bisphenol produced by the above-mentioned method for producing bisphenol.

As a result of intensive research conducted by the present inventors to solve the above problems, it has been found that a solution obtained by mixing an acid catalyst and an aromatic alcohol is used as mixed solution A, and a ketone or aldehyde is dropwise fed to mixed solution A as a dropwise feed solution, or mixed solution A is dropwise fed to a ketone or an aldehyde as a dropwise feed solution, thereby controlling the drip rate of the drip feed solution, lowering the temperature in the reaction tank before the entire amount of the drip feed material is dripped, and precipitating bisphenol crystals at any desired timing ^.
It was also found that the use of this bisphenol made it possible to produce a polycarbonate resin with excellent color tone, thereby completing the present invention.

That is, the gist of the present invention lies in the following [1] to [7].
[1] A method for producing bisphenol by condensing a ketone or an aldehyde with an aromatic alcohol in the presence of an acid catalyst,
The following steps (A) to (C) are satisfied:
After the dripping rate of the dripping supply liquid in the following step (B) reaches 80% or less of the total amount and is stopped,
A method for producing bisphenol, comprising carrying out the following step (C):
Step (A): A step of mixing the acid catalyst and the aromatic alcohol to obtain a mixed liquid A. Step (B): A step of dripping the ketone or aldehyde as a dripping supply liquid to the mixed liquid A, or dripping the mixed liquid A as a dripping supply liquid to the ketone or aldehyde, thereby obtaining a bisphenol reaction liquid. Step (C): A step of precipitating bisphenol crystals from the bisphenol reaction liquid. [2] The method for producing bisphenol according to [1], wherein the dripping supply of the step (B) is resumed after the step (C).
[3] The method for producing bisphenol according to [1] or [2], wherein the reaction temperature in the step (B) is 60° C. or lower.
[4] The temperature difference between the step (B) and the step (C) is 5° C. or more and 50° C. or less. [1]
The method for producing bisphenol according to any one of the above items (1) to (3).
[5] The method for producing bisphenol according to any one of [1] to [4], wherein the acid catalyst is selected from one or more of sulfuric acid, hydrogen chloride gas, hydrochloric acid, phosphoric acid, aromatic sulfonic acids, and aliphatic sulfonic acids.
[6] The method for producing bisphenol according to any one of [1] to [5], wherein in step (A), the components are mixed in the presence of an aromatic hydrocarbon and an aliphatic monoalcohol.
[7] The slurry concentration of the bisphenol reaction liquid is 30% or more, [1] to [6].
3. The method for producing bisphenol according to claim 1 ,
[8] The bisphenol is 2,2-bis(4-hydroxy-3-methylphenyl).
The method for producing bisphenol according to any one of [1] to [7], which contains one or more selected from propane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, and 1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane.
[9] A method for producing a polycarbonate resin, comprising the steps of: producing a polycarbonate resin by using a bisphenol produced by the method for producing a bisphenol according to any one of [1] to [8].

According to the present invention, there is provided a process for producing bisphenol which maintains the selectivity of the target bisphenol even on an industrial production scale, improves the mixability of the reaction solution, and produces a bisphenol with a good color tone.
Furthermore, the method for producing a polycarbonate resin using this bisphenol provides a polycarbonate resin with excellent color tone.

The following is a detailed description of the embodiments of the present invention, but the following description of the constituent elements is one example (representative example) of the embodiment of the present invention, and the present invention is not limited to the following content unless the gist of the present invention is changed. Note that in this specification, when the expression "~" is used, it is used as an expression including the numerical values or physical property values before and after it.

One embodiment of the present invention is a method for producing bisphenol, which is produced by condensing a ketone or an aldehyde with an aromatic alcohol in the presence of an acid catalyst, and is characterized by comprising the steps of: a step (A) of mixing the aromatic alcohol with the acid catalyst to obtain a mixed liquid; a step (B) of dropwise supplying a ketone or an aldehyde as a dropwise supply liquid to the mixed liquid A, or dropwise supplying the mixed liquid A as a dropwise supply liquid to the ketone or the aldehyde, and stopping the supply when a drip rate of the dropwise supply liquid becomes 80% or less; and a step (C) of precipitating crystals of bisphenol.

The inventors have found that by temporarily stopping the supply of the dropwise supply solution and lowering the temperature of the reaction solution, crystals can be precipitated early and the mixability of the reaction solution can be improved even under conditions of high bisphenol slurry concentration, making it possible to produce bisphenol on an industrial scale. The improved mixability also makes it possible to obtain bisphenol with good color tone in high yield and high selectivity.

<Production method of bisphenol>
In this embodiment, bisphenol is produced by a condensation reaction between an aromatic alcohol and a ketone or an aldehyde in the presence of an acid catalyst.

[Bisphenol]
The bisphenol produced in the present invention is usually a compound represented by the following general formula (1).

R ¹ to R ⁴ each independently include a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, and the like, and examples thereof include a proton; a halogen atom such as a fluoro group, a chloro group, a bromo group, or an iodo group; a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a t-butyl group, an n-pentyl group, an i-pentyl group, an n-
Chain alkyl groups such as a hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, an n-decyl group, an n-undecyl group, or an n-dodecyl group; a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, an n-butoxy group, an i-butoxy group, a t-butoxy group, an n-pentyloxy group, an i-pentyloxy group, an n-hexyloxy group, or an n-heptyloxy group,
Examples of such groups include alkoxy groups such as n-octyloxy, n-nonyloxy, n-decyloxy, n-undecyloxy, and n-dodecyloxy groups, cyclic alkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, and cyclododecyl groups, and aryl groups such as benzyl, phenyl, tolyl, and 2,6-dimethylphenyl groups. Of these, if ^R2 and ^R3 are sterically bulky, the condensation reaction does not proceed easily, and therefore protons are preferred.

^R5 and ^R6 each independently include a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, and the like, and examples thereof include a proton; a chain alkyl group such as a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a t-butyl group, an n-pentyl group, an i-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, a 2-ethylhexyl group, an n-nonyl group, an n-decyl group, an n-undecyl group, or an n-dodecyl group; a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, or the like. alkoxy groups such as an n-butoxy group, an i-butoxy group, a t-butoxy group, an n-pentyloxy group, an i-pentyloxy group, an n-hexyloxy group, an n-heptyloxy group, an n-octyloxy group, an n-nonyloxy group, an n-decyloxy group, an n-undecyloxy group, or an n-dodecyloxy group; cyclic alkyl groups such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, or a cyclododecyl group; a benzyl group, a phenyl group,
Examples of the aryl group include a tolyl group and a 2,6-dimethylphenyl group.

^R5 and ^R6 may be bonded or bridged to each other between the two groups, for example, cyclopropylidene, cyclobutylidene, cyclopentylidene, cyclohexylidene, 3,3,5
-trimethylcyclohexylidene, cycloheptylidene, cyclooctylidene, cyclononylidene, cyclodecylidene, cycloundecylidene, cyclododecylidene, fluorenylidene, xanthonylidene, thioxanthonylidene, and the like.

Specific examples of the bisphenols used in the present invention include 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 2,2
-Bis(4-hydroxy-3,5-dimethylphenyl)propane, 1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane, 9,9-bis(4-hydroxy-3-
methylphenyl)fluorene, 3,3-bis(4-hydroxyphenyl)pentane, 3,
3-bis(4-hydroxy-3-methylphenyl)pentane, 2,2-bis(4-hydroxyphenyl)pentane, 2,2-bis(4-hydroxy-3-methylphenyl)pentane, 3,3-bis(4-hydroxyphenyl)heptane, 3,3-bis(4-hydroxy-3-methylphenyl)heptane, 2,2-bis(4-hydroxyphenyl)heptane,
Examples of the hydroxyphenyl ether include, but are not limited to, 2,2-bis(4-hydroxy-3-methylphenyl)heptane, 4,4-bis(4-hydroxyphenyl)heptane, and 4,4-bis(4-hydroxy-3-methylphenyl)heptane.

Among these, a suitable bisphenol is any one selected from the group consisting of 2,2-bis(4-hydroxy-3-methylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, and 1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane, and more preferably 2,2-bis(4-hydroxy-3
1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane;

[Aromatic alcohol]
The aromatic alcohol used in the process for producing bisphenol of the present invention is usually a compound represented by the following general formula (2).

R ¹ to R ⁴ each independently include a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, and the like, and examples thereof include a proton; a halogen atom such as a fluoro group, a chloro group, a bromo group, or an iodo group; a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a t-butyl group, an n-pentyl group, an i-pentyl group, an n-
Chain alkyl groups such as a hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, an n-decyl group, an n-undecyl group, or an n-dodecyl group; a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, an n-butoxy group, an i-butoxy group, a t-butoxy group, an n-pentyloxy group, an i-pentyloxy group, an n-hexyloxy group, or an n-heptyloxy group,
Examples of the alkyl group include alkoxy groups such as an n-octyloxy group, an n-nonyloxy group, an n-decyloxy group, an n-undecyloxy group, and an n-dodecyloxy group; cyclic alkyl groups such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, and a cyclododecyl group; and aryl groups such as a benzyl group, a phenyl group, a tolyl group, and a 2,6-dimethylphenyl group.

Of these, ^R2 and ^R3 are preferably hydrogen atoms because the condensation reaction is difficult to proceed if they are sterically bulky. It is more preferable that ^R1 to ^R4 are each independently a hydrogen atom or an alkyl group, and ^R1 and ^R4 are each independently a hydrogen atom or an alkyl group, and R2 is preferably a hydrogen atom or an alkyl group.
, R3 is more preferably a hydrogen atom.

Specific examples of the compound represented by the above general formula (2) include phenol, cresol, xylenol, ethylphenol, propylphenol, butylphenol, methoxyphenol, ethoxyphenol, propoxyphenol, butoxyphenol, benzylphenol, and phenylphenol.

Among these, any one selected from the group consisting of phenol, cresol, and xylenol is preferable, cresol or xylenol is more preferable, and cresol is even more preferable.

[Ketone or aldehyde]
The ketone or aldehyde used in the production method of the present invention is usually a compound represented by the following general formula (3).

In the general formula (3), ^R5 and ^R6 each independently represent a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, etc. The alkyl group, alkoxy group, aryl group, etc. may be substituted or unsubstituted. For example, a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a t-butyl group,
n-pentyl group, i-pentyl group, n-hexyl group, n-heptyl group, n-octyl group,
2-ethylhexyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, methoxy group, ethoxy group, n-propoxy group, i-propoxy group, n-butoxy group,
i-butoxy group, t-butoxy group, n-pentyloxy group, i-pentyloxy group, n-
Examples of the aryl group include a hexyloxy group, an n-heptyloxy group, an n-octyloxy group, an n-nonyloxy group, an n-decyloxy group, an n-undecyloxy group, an n-dodecyloxy group, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclododecyl group, a benzyl group, a phenyl group, a tolyl group, and a 2,6-dimethylphenyl group.

^R5 and ^R6 may be bonded or bridged to each other between the two groups, or ^R5 and ^R6 may be bonded together with adjacent carbon atoms to form a cycloalkylidene group which may contain a heteroatom. The cycloalkylidene group is a divalent group obtained by removing two hydrogen atoms from one carbon atom of a cycloalkane.

Examples of the cycloalkylidene group formed by bonding ^R5 and ^R6 together with the adjacent carbon atoms include cyclopropylidene, cyclobutylidene, cyclopentylidene, cyclohexylidene, 3,3,5-trimethylcyclohexylidene, cycloheptylidene, cyclooctylidene, cyclononylidene, cyclodecylidene, cycloundecylidene, cyclododecylidene, fluorenylidene, xanthonylidene, and thioxanthonylidene.

Specific examples of the compound represented by the above general formula (3) include aldehydes such as formaldehyde, acetaldehyde, propionaldehyde, butylaldehyde, pentylaldehyde, hexylaldehyde, heptylaldehyde, octylaldehyde, nonylaldehyde, decylaldehyde, undecylaldehyde, and dodecylaldehyde; ketones such as acetone, butanone, pentanone, hexanone, heptanone, octanone, nonanone, decanone, undecanone, and dodecanone; and benzaldehyde. aryl alkyl ketones such as phenyl methyl ketone, phenyl ethyl ketone, phenyl propyl ketone, cresyl methyl ketone, cresyl ethyl ketone, cresyl propyl ketone, xylyl methyl ketone, xylyl ethyl ketone, and xylyl propyl ketone; and cyclic alkane ketones such as cyclopropanone, cyclobutanone, cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, cyclononanone, cyclodecanone, cycloundecanone, and cyclododecanone. Among these, acetone is preferable.

When the molar ratio of aromatic alcohol to ketone or aldehyde used in condensation (moles of aromatic alcohol/moles of ketone) or (moles of aromatic alcohol/moles of aldehyde) is low, a large amount of a self-condensation reaction product of ketone or aldehyde is produced as a by-product.
It is preferably 1.0 or more, more preferably 1.2 or more, and even more preferably 1.5 or more.
If the molar ratio is high, it takes time to recover the unreacted aromatic alcohol.
It is preferably 20 or less, more preferably 15 or less, and even more preferably 10 or less.

[Acid Catalyst]
As the acid catalyst in the process for producing bisphenol of the present invention, sulfuric acid, hydrogen chloride gas, hydrochloric acid, aromatic sulfonic acids such as p-toluenesulfonic acid, aliphatic sulfonic acids such as methanesulfonic acid, phosphoric acid, etc. can be used.

Among them, the acid catalyst is preferably one or more selected from the group consisting of sulfuric acid, hydrogen chloride gas, hydrochloric acid, aromatic sulfonic acid, and aliphatic sulfonic acid. In the condensation reaction of aromatic alcohol and ketone or aldehyde, phosphoric acid has low reactivity, bisphenol is difficult to precipitate, and it is difficult to perform the condensation reaction in a slurry state, so that the yield and quality of bisphenol tend to be easily reduced. More preferably, it is preferably one or more selected from the group consisting of sulfuric acid, hydrogen chloride gas, and hydrochloric acid, and even more preferably, sulfuric acid and/or hydrogen chloride gas. From the viewpoint of excellent reaction efficiency, no volatility of the catalyst, and less burden on the equipment, sulfuric acid is particularly preferable.

Sulfuric acid is an acidic liquid represented by the chemical formula H ₂ SO _4. Generally, sulfuric acid is used as an aqueous sulfuric acid solution diluted with water, and is called concentrated sulfuric acid or dilute sulfuric acid depending on its concentration. For example, dilute sulfuric acid is an aqueous sulfuric acid solution with a mass concentration of less than 50% by mass. When the concentration of sulfuric acid used (the concentration of H ₂ SO ₄ in the aqueous sulfuric acid solution (H ₂ SO ₄ +H ₂ O)) is at least a certain level, the amount of water contained is reduced, so that the reaction of producing bisphenol proceeds more easily, the reaction time for producing bisphenol is shortened, and bisphenol can be produced efficiently. Therefore, the concentration of sulfuric acid used is preferably 70% by mass or more, more preferably 75% by mass or more, and even more preferably 80% by mass or more. In addition, the upper limit of the concentration of sulfuric acid used is usually 99.5% by mass or less or 99% by mass or less.

If the molar ratio of the acid catalyst to the aromatic alcohol raw material (moles of acid catalyst/moles of aromatic alcohol) is low, the acid catalyst is diluted by the water by-produced as the condensation reaction proceeds, and the reaction takes time. If the molar ratio is high, a large amount of by-products may be produced. For these reasons, the molar ratio of the acid catalyst to the aromatic alcohol raw material in the reaction liquid is preferably 0.001 or more, more preferably 0.005 or more, and even more preferably 0.
It is preferably 0.01 or more, and is preferably 10 or less, more preferably 5 or less, even more preferably 3 or less, and particularly preferably 1 or less.

[Thiol cocatalyst]
In the reaction step, a thiol may be used as a promoter when condensing a ketone with an aromatic alcohol.
For example, in the production of 2,2-bis(4-hydroxy-3-methylphenyl)propane, the production of 24 (2-(2-hydroxy-3-methylphenyl)-2-(4-hydroxy-3-methylphenyl)propane) is suppressed by using thiol as a co-catalyst.
In addition to the effect of increasing the selectivity of the thiol to the olefin (2,2-bis(4-hydroxy-3-methylphenyl)propane), the effect of enhancing the polymerization activity during the production of a polycarbonate resin and improving the color tone of the resulting polycarbonate resin is obtained. Although the details of the reasons for this improvement in the polymerization activity during the production of a polycarbonate resin and the effect of improving the color tone of the resulting polycarbonate resin are not clear, it is presumed that the use of a thiol makes it possible to suppress the production of inhibitors to the polymerization reaction for producing a polycarbonate resin and to suppress the production of substances that deteriorate the color tone.

Examples of thiols used as cocatalysts include mercaptoacetic acid, thioglycolic acid,
Mercaptocarboxylic acids such as 2-mercaptopropionic acid, 3-mercaptopropionic acid, and 4-mercaptobutyric acid, methyl mercaptan, ethyl mercaptan, propyl mercaptan, butyl mercaptan, pentyl mercaptan, hexyl mercaptan, heptyl mercaptan, octyl mercaptan, nonyl mercaptan, decyl mercaptan (decanethiol), undecyl mercaptan (undecanethiol), dodecyl mercaptan (
dodecanethiol), tridecyl mercaptan, tetradecyl mercaptan, pentadecyl mercaptan and other alkyl thiols; and mercaptophenol and other aryl thiols.

Regarding the molar ratio of thiol to ketone used in the condensation reaction (moles of thiol/moles of ketone), from the viewpoint of effectively improving the reaction selectivity of bisphenol, the lower limit of the molar ratio of thiol to ketone is preferably 0.001 or more, more preferably 0.005 or more, and even more preferably 0.01 or more. Also, from the viewpoint of preventing contamination of bisphenol, the upper limit is preferably 1 or less, more preferably 0.5 or less, and even more preferably 0.1 or less.

[Organic solvent]
The reaction for producing bisphenol may be carried out in the presence of an organic solvent. Examples of the organic solvent include aromatic hydrocarbons, aliphatic monoalcohols, and aliphatic hydrocarbons. These solvents may contain two or more kinds. For example, a mixed solvent of an aromatic hydrocarbon and an aliphatic alcohol may be used.
Examples of aromatic hydrocarbons include benzene, toluene, xylene, ethylbenzene,
Examples include diethylbenzene, isopropylbenzene, and mesitylene.

Examples of aliphatic monoalcohols include methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, t-butanol, n-pentanol, i-pentanol, n-hexanol, n-heptanol, n-octanol, and n
Examples of the alcohol include monohydric alkyl alcohols such as n-nonanol, n-decanol, n-undecanol, and n-dodecanol; and polyhydric alcohols such as ethylene glycol, diethylene glycol, and triethylene glycol.
From the viewpoint of reaction efficiency and the like, the aliphatic monoalcohol is preferably a monohydric alkyl alcohol having 1 to 12 carbon atoms, and more preferably a monohydric alkyl alcohol having 1 to 8 carbon atoms.

Incidentally, a large amount of the aromatic alcohol, which is the raw material, may be used in place of the organic solvent.
In this case, the unreacted aromatic alcohol is lost, but the loss can be reduced by recovering and purifying it by distillation or the like and reusing it.

When a solvent is used, the mass ratio of the solvent to the raw material ketone or aldehyde ((mass of organic solvent/mass of ketone) or (mass of organic solvent/mass of aldehyde)) is preferably 0.5 or more, and more preferably 1 or more, from the viewpoint of suppressing poor mixing and polymerization of the ketone or aldehyde, and from the viewpoint of reaction efficiency, the upper limit may be adjusted depending on the type of solvent within a range in which precipitation of bisphenol occurs, and may be 50 or less, or may be 30 or less.

The generated bisphenol is less likely to decompose if it is dispersed in the organic solvent rather than being completely dissolved. In addition, this can reduce losses during recovery of bisphenol from the resulting bisphenol solution after the reaction is completed (for example, losses to the filtrate during crystallization).
It is preferable to use a solvent in which bisphenol has low solubility. Examples of solvents in which bisphenol has low solubility include aromatic hydrocarbons. For this reason, the organic solvent preferably contains aromatic hydrocarbons, and one of the preferred aromatic hydrocarbons is toluene, since bisphenol is difficult to dissolve in this solvent and it has a low boiling point.

[Step (A)]
The method for producing bisphenol of the present invention includes a step (A) of mixing an aromatic alcohol with an acid catalyst to obtain a mixed liquid. The method for mixing the aromatic alcohol with the acid catalyst is not particularly limited, and they may be mixed by a known method. The mixed liquid A containing the aromatic alcohol and the acid catalyst may be composed of the aromatic alcohol and the acid catalyst, or may contain other components. For example, it may be a mixed liquid containing an aromatic alcohol, an acid catalyst, and an organic solvent.

The content of the aromatic alcohol in the mixed liquid A is not particularly limited, but from the viewpoint of efficiently producing bisphenol (enabling to improve the conversion rate of ketone or aldehyde and the selectivity of bisphenol), it is usually 5 mol % or more, preferably 10 mol % or more, more preferably 15 mol % or more, and even more preferably 20 mol % or more, and is usually 99.9 mol % or less, preferably 99.5 mol % or less, more preferably 99 mol % or less, and even more preferably 98.5 mol % or less.

The content of the acid catalyst in the mixed solution A is not particularly limited, but from the viewpoint of efficiently producing bisphenol, it is usually 0.1 mol% or more, preferably 0.2 mol% or more, more preferably 0.5 mol% or more, and even more preferably 1.0 mol% or more, and is usually 50 mol% or less, preferably 40 mol% or less, and even more preferably 30 mol% or less.
It is more preferably not more than mol %, and even more preferably not more than 20 mol %.

The molar ratio of the acid catalyst to the aromatic alcohol in the mixed liquid A can be the same as the molar ratio of the acid catalyst to the aromatic alcohol in the reaction liquid described above, from the same viewpoint.
The type of solvent that can be used is not particularly limited as long as it can uniformly disperse the aromatic alcohol and the acid catalyst. For example, aliphatic alcohols such as methanol and ethanol, toluene,
Aromatic hydrocarbons such as xylene can be used, and methanol and toluene are particularly preferred.

When a solvent is used, the content of the solvent in the mixed solution A is not particularly limited, but from the viewpoint of efficiently producing bisphenol, it is usually 0.1 mol % or more, preferably 0.5 mol % or more, more preferably 1.0 mol % or more, and even more preferably 2.0 mol % or more, and is usually 80 mol % or less, preferably 70 mol % or less, and more preferably 60 mol % or less.

[Step (B)]
The method for producing bisphenol of the present invention includes a step (B) of dripping a ketone or aldehyde as a dripping feed liquid to the above-mentioned mixed liquid A to obtain a bisphenol reaction liquid, or dripping the above-mentioned mixed liquid A as a dripping feed liquid to a ketone or an aldehyde to obtain a bisphenol reaction liquid.
The ketone or aldehyde may be used alone, or may be simultaneously supplied dropwise with a thiol promoter, or may be mixed with a ketone or aldehyde, a thiol promoter and an organic solvent, and the resulting mixture B may be supplied dropwise to the mixture A, or the mixture A may be supplied dropwise to the mixture B.
The dripping supply liquid here refers to the entire liquid dripped to the reaction liquid, and as described above, the dripping supply liquid may be a ketone or aldehyde, or may be mixed liquid A, and may contain other components such as a thiol promoter, an organic solvent, etc. In addition, the dripping supply liquid may be dripped in a state in which all components are mixed, or may be dripped separately.

Among the above dropwise supply methods, a method in which mixed solution B, which is a mixture of a ketone or aldehyde, a thiol co-catalyst, and an organic solvent, is supplied to mixed solution A is preferred, from the viewpoint that when a ketone or aldehyde is supplied to mixed solution A, the reaction can be progressed simultaneously with the dropwise supply because the entire amount of the acid catalyst is contained in the reaction solution, thereby improving the efficiency of bisphenol production.

In the case of producing mixed liquid B, step (B) includes a step of mixing a ketone or aldehyde, a thiol co-catalyst, and an organic solvent to obtain mixed liquid B, and a step of dropwise feeding mixed liquid B as a dropwise feeding liquid to mixed liquid A, or dropwise feeding mixed liquid A as a dropwise feeding liquid to mixed liquid B, to obtain a bisphenol reaction liquid.
When mixed liquid B is dropwise supplied as a dropwise supply liquid to mixed liquid A, or when mixed liquid A is dropwise supplied as a dropwise supply liquid to mixed liquid B, the entire amount of the dropwise supply liquid is not supplied at once, but is supplied dropwise in a number of times. At this time, it is preferable to carry out the dropping while grasping the amount to be dropped.

In the case of producing the mixed solution B, the content of the ketone or aldehyde in the mixed solution B is not particularly limited, but from the viewpoint of efficiently producing bisphenol, it is usually 10 mol % or more.
It is preferably 20 mol % or more, more preferably 30 mol % or more, and more preferably 40
% or more, and is usually 99.5 mol % or less, and more preferably 99.
It is preferably 0 mol % or less, more preferably 98.5 mol % or less,
It is more preferably 8.0 mol % or less.

When producing the mixed solution B, the content of the thiol promoter in the mixed solution B is not particularly limited, but from the viewpoint of efficiently producing bisphenol, it is usually 0.1 mol % or more, and 0.2 mol % or less.
% or more, more preferably 0.3 mol % or more, and more preferably 0.4 mol % or more.
% or more, and more preferably 50 mol % or less, and more preferably 40 mol % or less.
It is preferably 30 mol % or less, more preferably 30 mol % or less, and even more preferably 20 mol % or less.

The molar ratio of the aromatic alcohol to the ketone or aldehyde in the mixed solution A can be the same as the molar ratio of the aromatic alcohol to the ketone or aldehyde in the above-mentioned reaction solution from the same viewpoint. Also, the molar ratio of the thiol promoter to the ketone can be the same as the molar ratio of the thiol promoter to the ketone from the same viewpoint.

Regarding the organic solvent, when the ketone or aldehyde and the thiol co-catalyst are separately fed to the mixture A, each component may be dissolved/mixed in the same or different organic solvent;
Alternatively, when preparing mixture B, the ketone or aldehyde and the thiol promoter may be dissolved/mixed in one or more solvents.
The type of organic solvent that can be used is not particularly limited as long as it can dissolve/mix the ketone or aldehyde and the thiol promoter. For example, benzene, toluene, xylene, etc. can be used, with toluene and xylene being particularly preferred.

When an organic solvent is used, the amount of the organic solvent in step (B) relative to the total amount of the solution to be dropped in step (B) is
The content of the organic solvent supplied in step (in the case of producing mixed solution B, the content of the organic solvent in mixed solution B) is not particularly limited, but from the viewpoint of efficient production of bisphenol, it is usually 1 mol % or more, preferably 2 mol % or more, more preferably 3 mol % or more, and even more preferably 4 mol % or more, and is usually 80 mol % or less, preferably 70 mol % or less, and more preferably 60 mol % or less, and is preferably 50 mol % or less.
It is more preferably 0 mol % or less.

If the reaction temperature is too low, the condensation reaction does not proceed easily, and therefore the reaction temperature is preferably −30° C. or higher, more preferably −20° C. or higher, and even more preferably −15° C. or higher. If the reaction temperature is too high, a side reaction, the self-condensation reaction of acetone or ketone, proceeds,
When a thiol promoter is used, the oxidative decomposition of the thiol tends to proceed, so the reaction temperature is preferably 60° C. or lower, more preferably 50° C. or lower, and even more preferably 40° C. or lower.

The drip feed rate is not particularly limited, but since the condensation reaction of bisphenol is an exothermic reaction, it is desirable to adjust the drip feed rate so as to obtain the desired reaction temperature. In addition, the larger the reaction vessel, the smaller the heat transfer area relative to the reaction vessel volume, so the heat removal efficiency deteriorates. Therefore, it is preferable to adjust the drip feed rate according to the reaction vessel volume and heat removal capacity. From the above, the drip feed rate is determined by the drip rate of the drip feed liquid per hour {
When expressed as {mass of the dripping supply liquid supplied to the dripping supply liquid/total mass of the dripping supply liquid)÷time}, it is preferable that the dripping rate is 3.0/Hr or less. Also, if the feed rate is slow, it takes time to complete the reaction and the kettle efficiency deteriorates, so it is preferable that the dripping amount per hour with respect to the total dripping supply amount is 0.05 to 0.05.
It is preferable that the rate is 1/Hr or more.

The drip rate of the solution dripped in step (B) is 20% or more because if it is too low, bisphenol is not sufficiently produced and crystals do not precipitate, and if it is too high, crystals precipitate naturally and the stirring efficiency decreases, so the drip rate is preferably 80% or less, more preferably 70% or less, and even more preferably 60% or less.

[Step (C)]
In the method for producing bisphenol according to the present invention, when the dripping rate of the dripping supply liquid in the step (B) reaches 20% or more, the dripping supply is stopped, and the temperature of the bisphenol reaction liquid is kept at 5° C. to 5° C.
0° C. to precipitate bisphenol crystals, and after the precipitation of the crystals, the supply of the dropwise supply liquid supplied in step (B) is resumed to obtain a bisphenol reaction liquid.

The reaction time of the condensation reaction is adjusted as appropriate depending on the reaction conditions such as the type of bisphenol to be produced, the reaction temperature, and the production scale, but is usually 500 hours or less, and may be 400 hours or less or 350 hours or less. If the reaction is continued for a long time, the produced bisphenol will decompose, so the reaction time is preferably 30 hours or less, more preferably 25 hours or less, and even more preferably 20 hours or less. The lower limit of the reaction time is usually 0.5 hours or more, and 1 hour or more.
It is preferably 1.5 hours or more, and more preferably 1.5 hours or more.

In this specification, the reaction time includes the time for mixing the aromatic alcohol with the ketone or aldehyde. For example, a mixture A of an aromatic alcohol and an acid catalyst is added to the mixture A.
Mixture B was added dropwise over 1 hour, crystals were precipitated over 1 hour, and then mixture B was added dropwise again over 1 hour.
In the case where the reaction is carried out for one hour after the supply of the components over a period of time, the reaction time is four hours.
The reaction can also be stopped, for example, by adding water or a base in an amount equal to or greater than the amount of the acid catalyst used to reduce the concentration of the acid catalyst.

[Reaction vessel and stirring speed]
Since the reaction to produce bisphenol proceeds with a strong acid as a catalyst, it is preferable that the surface of the inner wall of the reaction vessel is made of a corrosion-resistant material. In particular, it is preferable to use a reaction vessel made of glass lining, which has excellent corrosion resistance. The size of the reaction vessel is selected according to the production volume. The size of a general reaction vessel is 0.5 ^m3 or more and 20 ^m3 or less, and 1 ^m3 or more and 10 ^m3 or less is more preferable. When the size of the reaction vessel is changed, the stirring rotation speed also changes, and generally, when the size of the reaction vessel is increased, the rotation speed is decreased because the stirring is performed in accordance with the power. When the rotation speed is decreased, the heat of reaction is not sufficiently removed, and when the rotation speed is increased, the stirring power is loaded, and there is a risk of the device being damaged. Therefore, the stirring speed is preferably 10 rpm or more and 800 rpm or more.
m or less, more preferably 20 rpm or more and 700 rpm or less, and still more preferably 30 rpm or more and 300 rpm or less.
rpm or less is even more preferable.

[Purification method]
The method for producing bisphenol of the present invention may include other steps in addition to the above steps (A) to (C), for example, a step of purifying the bisphenol obtained in step (C). The method for purifying bisphenol is not particularly limited and can be performed by a conventional method. For example, purification can be performed by a simple means such as crystallization or column chromatography. Specifically, after the condensation reaction, the organic phase obtained by separating the reaction liquid is washed with water or saline, and further neutralized and washed with sodium bicarbonate water, if necessary. Next, the organic phase after washing is cooled and crystallized. When a large amount of aromatic alcohol is used, the excess aromatic alcohol is distilled off before the crystallization and then crystallized.

The precipitated bisphenol may be subjected to suspension washing using an aromatic hydrocarbon or the like as a washing solvent, or may be dried. The drying method may be drying under reduced pressure or drying under normal pressure. The drying temperature may be appropriately determined, and may be, for example, 50 to 120° C. and 2 to 40° C.
Allow to dry for 15 hours.

[Uses of bisphenol]
Bisphenols are used in optical materials, recording materials, insulating materials, transparent materials, electronic materials, adhesive materials,
They can be used as components, curing agents, additives, or precursors thereof for various thermoplastic resins such as polyether resins, polyester resins, polyarylate resins, polycarbonate resins, polyurethane resins, and acrylic resins, which are used in various applications such as heat-resistant materials, and various thermosetting resins such as epoxy resins, unsaturated polyester resins, phenolic resins, polybenzoxazine resins, and cyanate resins, etc. They are also useful as additives for color developers, anti-fading agents, bactericides, antibacterial and antifungal agents, etc. for heat-sensitive recording materials, etc.

Among these, it is preferable to use it as a raw material (monomer) of thermoplastic resins and thermosetting resins because it can impart good mechanical properties, and more preferably as a raw material of polycarbonate resins and epoxy resins. It is also preferable to use it as a color developer, and more preferably to use it in combination with a leuco dye and a discoloration temperature regulator.

<Production method of polycarbonate resin>
A method for producing a polycarbonate resin, which includes a step of polymerizing a polycarbonate using the bisphenol obtained by the bisphenol production method of the present invention as a raw material, will be described. The polycarbonate resin can be produced by a method of, for example, transesterifying a bisphenol with a carbonate diester such as diphenyl carbonate in the presence of an alkali metal compound and/or an alkaline earth metal compound. The transesterification reaction can be carried out by appropriately selecting a known method, but an example of a production method using bisphenol and diphenyl carbonate as raw materials will be described below.

In the method for producing a polycarbonate resin of the present invention, it is preferable to use an excess amount of diphenyl carbonate relative to the bisphenol. The amount of diphenyl carbonate used relative to the bisphenol is preferably large in terms of the amount of terminal hydroxyl groups in the produced polycarbonate resin and excellent thermal stability of the polymer, and is preferably small in terms of the rate of transesterification reaction being high and making it easy to produce a polycarbonate resin with a desired molecular weight.
The amount of diphenyl carbonate used per 1.0 mole of bisphenol is usually 1.001 mole or more, preferably 1.002 mole or more, and usually 1.3 mole or less, preferably 1.002 mole or more.
. 2 moles or less.

As for the method of supplying the raw materials, bisphenol and diphenyl carbonate can be supplied in a solid state, but it is preferable to melt one or both of them and supply them in a liquid state.
When producing a polycarbonate resin by the transesterification reaction of diphenyl carbonate and bisphenol, a transesterification catalyst is usually used. As the transesterification catalyst, it is preferable to use an alkali metal compound and/or an alkaline earth metal compound. These may be used alone or in any combination and ratio of two or more. In practical use, it is preferable to use an alkali metal compound.

The amount of catalyst used per mole of bisphenol or diphenyl carbonate is usually 0.05
μmol or more, preferably 0.08 μmol or more, more preferably 0.10 μmol or more, and usually 100 μmol or less, preferably 50 μmol or less, more preferably 20 μmol or less.
It is less than a mole.

When the amount of the catalyst used is within the above range, it is easy to obtain the polymerization activity required for producing a polycarbonate resin having a desired molecular weight, and it is easy to obtain a polycarbonate resin that has excellent polymer hue, does not undergo excessive polymer branching, and has excellent fluidity during molding.

In producing a polycarbonate resin by the above method, it is preferable to continuously feed both of the above raw materials to a raw material mixing tank, and then continuously feed the resulting mixture and the transesterification catalyst to a polymerization tank.
In the production of polycarbonate resins by the transesterification method, usually, both raw materials are fed into a raw material mixing tank, stirred uniformly, and then fed into a polymerization tank to which a catalyst is added, thereby producing a polymer.

The present invention will be described in more detail below with reference to examples and comparative examples. However, the present invention is not limited to the following examples as long as it does not depart from the gist of the present invention.

[Raw materials and reagents]
Orthocresol, acetone, toluene, sulfuric acid, dodecanethiol, methanol, sodium hydroxide, sodium hydrogen carbonate, and cesium carbonate were obtained from Wako Pure Chemical Industries, Ltd.
Diphenyl carbonate used was a product manufactured by Mitsubishi Chemical Corporation.

[evaluation]
<Miscibility of bisphenol reaction solution>
The mixability of the bisphenol reaction liquid was evaluated visually based on the following criteria.
⊚: No solid accumulation or drift of bisphenol was observed.
○: Bisphenol solids are locally deposited, and some drift is observed.
△: Bisphenol solids were deposited all over the mixture, making stirring impossible except near the stirring blades.
×: Bisphenol solids were deposited all over the sample, making stirring impossible.

<Composition analysis of reaction product liquid containing bisphenol>
The composition of the reaction product liquid containing bisphenol was analyzed by high performance liquid chromatography.
The following procedure and conditions were followed to calculate the concentration of bisphenol C based on ortho-cresol.
The mass of the organic phase used in calculating the concentration was calculated using the total theoretical mass of orthocresol, acetone, toluene, and dodecanethiol.
・Apparatus: Shimadzu Corporation "LC-2010A"
Column: Intact Corporation "Scherzo SM-C18", inner diameter 3 μm, length 250 mm, 3.0 mm ID
- Low pressure gradient method - Analysis temperature: 40°C
Eluent composition:
Solution A: Ammonium acetate: acetic acid: demineralized water = 3.000 g: 1 mL: 1 L of solution Solution B: Ammonium acetate: acetic acid: acetonitrile: demineralized water = 1.500 g: 1 mL: 90
0 mL: 150 mL solution. At analysis time 0 minutes, the eluent composition was A:B = 60:40 (volume ratio, same below).
During the analysis time from 0 to 42 minutes, the ratio of A solution to B solution was gradually changed to 10:90.
During the analysis time from 42 to 50 minutes, the ratio of A solution to B solution was maintained at 10:90.
The analysis was performed at a flow rate of 0.34 mL/min.
・Detection wavelength is 280 nm

<Evaluation of color tone>
The color tone of bisphenol was evaluated by the following method.
・Apparatus: SE6000 aluminum block heater manufactured by Nippon Denshoku Industries Co., Ltd. ・Instruments: Test tube manufactured by Nippon Denki Rika Glass Co., Ltd. (24 mm x 200 mm P-24)
20 g of bisphenol product was weighed out into a test tube and heated for 19 minutes using an aluminum block heater.
The mixture was heated to 0° C. and melted, and the Hazen color scale was measured 30 minutes after the start of heating.

[Example 1]
(Reaction step)
A 10 ^m3 glass-lined, fully jacketed reactor equipped with a thermometer (a baffle was placed 10 cm away from the reactor wall, and a thermosensor was placed inside the baffle to measure the temperature) and a stirrer was charged with 1,600 kg of ortho-cresol, 200 kg of toluene, and 1000 kg of toluene under a nitrogen atmosphere.
574 kg, 104.3 kg of methanol, and 660.9 kg of 98% by mass sulfuric acid were added and stirred and mixed to prepare mixed solution A. In addition, 424.3 kg of acetone, 347.8 kg of toluene, and 37.6 kg of dodecanethiol were stirred and mixed in a 3 ^m3 adjustment tank for 1 hour to prepare mixed solution B. When the internal temperature of the reaction tank to which mixed solution A was added was 5°C or less, the supply of mixed solution B was started from the adjustment tank using a pump. At this time, mixed solution B was dripped and supplied so that the internal temperature of the reaction tank did not exceed 10°C. After 3 hours, when the dripping rate of mixed solution B reached 67%, the supply was stopped, the temperature was lowered by 5°C, and crystals were precipitated. After the crystals were precipitated, the reaction solution was stirred for 1 hour, and then the supply of mixed solution B was resumed so that the internal temperature of the reaction tank did not exceed 10°C. After the entire amount was supplied,
The mixture was stirred for 2 hours. The maximum reaction temperature during the reaction was 9.4° C., which was 10° C. below the target temperature during the reaction.
It never exceeded °C.

When the inside of the reactor was checked, blade tracks were observed near the wall of the reactor, suggesting that segregation had occurred, but since the reaction temperature could be controlled to below 10°C, it was determined that there was no accumulation of bisphenol C crystals. Therefore, the mixability of the bisphenol reaction liquid was rated as good.
Thereafter, 1,322 kg of a 25% aqueous solution of sodium hydroxide was added to reduce the acid concentration and terminate the reaction.

(Refining process)
The internal temperature of the reaction tank was raised to 80° C. while stirring the reaction liquid, and then the mixture was left to stand to separate the oil and water. The aqueous phase was extracted from the glass-lined reaction tank to obtain an organic phase. Demineralized water was added to this organic phase, and the mixture was stirred at 80° C., and then the mixture was left to stand to separate the oil and water. The aqueous phase was extracted from the glass-lined reaction tank. A 10% by mass aqueous solution of sodium bicarbonate was added to the obtained organic phase, and the mixture was stirred at 80° C. to perform neutralization washing. The mixture was then left to stand to separate the oil and water, and the aqueous phase was extracted. The obtained organic phase was transferred to a crystallization tank having the same equipment as the reaction tank, and neutralization washing was performed again in the same manner. Demineralized water was added to the obtained organic phase, and the mixture was stirred at 80° C., and then the mixture was left to stand to separate the oil and water, and the aqueous phase was extracted. This operation was performed seven times to obtain 4983.7 kg of an organic phase.
The organic phase thus obtained was analyzed by liquid chromatography. As a result, the yield of bisphenol C based on ortho-cresol was 79.6 mol %, and the selectivity based on ortho-cresol was 99.
It was mol %.

(Crystallization process)
The organic phase obtained in the purification step was gradually cooled from 80° C. to 20° C. to precipitate crystals of bisphenol C. It was further cooled to 5° C., and after the temperature reached 5° C., solid-liquid separation was performed using a centrifuge to obtain a crudely purified wet cake.
The crude wet cake was washed by sprinkling 4,350 kg of toluene, and then subjected to solid-liquid separation using a centrifuge to obtain 1,657 kg of purified wet cake. The slurry concentration of the reaction liquid was calculated from this result to be 33.2 mass %.
The resulting purified wet cake was placed in a Nauter dryer and dried to obtain 1,328 kg of a white solid. A portion of the resulting white solid was sampled and subjected to composition analysis by high performance liquid chromatography to confirm that the product was bisphenol C. The purity was 99.9 area %.
The color tone of the obtained bisphenol C was evaluated.
The APHA was 3.

[Example 2]
(Reaction step)
Ortho-cresol 2000 kg, toluene 2435 kg, methanol 130.4 kg,
Mixed solution A was prepared with 826.1 kg of 98% by mass sulfuric acid, mixed solution B was prepared with 530.4 kg of acetone, 434.8 kg of toluene, and 47 kg of dodecanethiol, and the reaction was carried out in the same manner as in Example 1, except that crystals were intentionally precipitated when the drop rate of mixed solution B reached 57% 3 hours after the start of the supply of mixed solution B. The maximum reaction temperature during the reaction was 9.6°C and did not exceed the target control temperature of 10°C during the reaction, the miscibility of the bisphenol reaction solution was rated as ⊚, and no drift was observed. After the reaction was completed, 1652 kg of a 25% aqueous sodium hydroxide solution was added,
The reaction was stopped.

(Refining process)
A purification step was carried out in the same manner as in Example 1 to obtain 5,447 kg of an organic phase. The obtained organic phase was analyzed by liquid chromatography to find that the yield of bisphenol C based on ortho-cresol was 83.5 mol % and the selectivity based on ortho-cresol was 98 mol %.

(Crystallization process)
Crystallization was carried out in the same manner as in Example 1 to obtain a crude wet cake, which was then mixed with 4350 kcal of toluene.
The mixture was washed with 21 g of water, and solid-liquid separation was performed using a centrifuge.
The slurry concentration in the reaction solution was 40.0% by mass. The resulting refined wet cake was placed in a Nauter dryer and dried to obtain 1,833 kg of a white solid.
A portion of the resulting white solid was sampled and subjected to composition analysis by high performance liquid chromatography, confirming that the product was bisphenol C. The purity was 99.9 area %. The color tone of the resulting bisphenol C was evaluated, and the Hazen color scale (APHA) was 4.

[Comparative Example 1]
(Reaction step)
A 4 ^m3 glass-lined, fully jacketed reactor equipped with a thermometer (a baffle was placed 7 cm away from the wall of the reactor, and a thermosensor was placed inside the baffle to measure the temperature) and an agitator was placed in a nitrogen atmosphere with 700 kg of ortho-cresol and 950 kg of toluene.
45.6 kg of methanol and 289.2 kg of 98% sulfuric acid were added and stirred to prepare a mixed solution A. In ^addition , 197.5 kg of acetone, 152 kg of toluene,
Mixture B was prepared by stirring and mixing 16.4 kg of dodecanethiol for 1 hour. When the internal temperature of the reaction tank to which mixture A was added was 5°C or less, the pump was used to start pumping mixture B from the adjustment tank. When the dripping rate of mixture B reached 90%, crystals began to precipitate, the viscosity of the slurry increased, and mixing was poor. As a result, the reaction temperature during the reaction exceeded the target control temperature of 10°C, and the temperature rose to a maximum of 18.0°C, making temperature control difficult. After 3 hours, the supply of the remaining mixture B was resumed, and mixture B was supplied over 3 hours with stirring.
The reaction was stopped by adding 577.3 kg of a 25% aqueous solution of sodium hydroxide.

(Refining process)
A purification step was carried out in the same manner as in Example 1 to obtain 2,016 kg of an organic phase. The obtained organic phase was analyzed by liquid chromatography, and as a result, the yield of bisphenol C based on ortho-cresol was 82 mol %, and the selectivity based on ortho-cresol was 96 mol %.

(Crystallization process)
Crystallization was carried out in the same manner as in Example 1 to obtain a crude wet cake, which was then mixed with 1880 kcal of toluene.
The mixture was washed with 72 g of water, and solid-liquid separation was performed using a centrifuge.
The slurry concentration of the reaction liquid was 35.7% by mass. The purified wet cake was dried using a conical dryer to obtain 608 kg of a white solid.
A portion of the resulting white solid was sampled and subjected to composition analysis by high performance liquid chromatography, confirming that the product was bisphenol C. The purity was 98.9 area %. The color tone of the resulting bisphenol C was measured, and the Hazen color scale (APHA) was 32.

Differences in the conditions in the above Examples 1 and 2 and Comparative Example 1, miscibility of the bisphenol reaction solution, differences from the target control temperature during the reaction, selectivity of bisphenol C based on ortho-cresol,
Slurry concentration, purity of the obtained bisphenol C, and Hazen color number (APHA)
are summarized in Table 1 below.
From Table 1 below, it can be seen that in the production of bisphenol, by stopping the supply of mixed solution B before the dropping rate of mixed solution B reaches 80% and causing crystals to precipitate early by lowering the temperature of the reaction solution, it is possible to maintain good mixability even under reaction conditions with a high bisphenol slurry concentration. It can be seen that it is now possible to obtain bisphenol with good color tone with high yield and high selectivity even on an industrial production scale.

According to the present invention, various bisphenols can be produced simply, efficiently, and industrially advantageously. The bisphenols produced by the method for producing bisphenols of the present invention have excellent polymerization activity and are therefore useful as raw materials for polymeric materials such as polycarbonate resins.

Claims (9)

A method for producing bisphenol by condensing a ketone or aldehyde with an aromatic alcohol in the presence of an acid catalyst,
The following steps (A) to (C) are satisfied:
After the dripping rate of the dripping supply liquid in the following step (B) reaches 80% or less of the total amount and is stopped,
A method for producing bisphenol, comprising carrying out the following step (C):
Step (A): A step of mixing the acid catalyst and the aromatic alcohol to obtain a mixed liquid A. Step (B): A step of dripping the ketone or aldehyde as a dripping supply liquid to the mixed liquid A, or dripping the mixed liquid A as a dripping supply liquid to the ketone or aldehyde, thereby obtaining a bisphenol reaction liquid. Step (C): A step of precipitating bisphenol crystals from the bisphenol reaction liquid. The method for producing bisphenol according to claim 1, wherein the dropwise supply of step (B) is resumed after step (C). The method for producing bisphenol according to claim 1, wherein the reaction temperature in the step (B) is 60° C. or lower. The method for producing bisphenol according to claim 1, wherein the temperature difference between the step (B) and the step (C) is 5°C or more and 50°C or less. 2. The method for producing bisphenol according to claim 1, wherein the acid catalyst is selected from one or more of sulfuric acid, hydrogen chloride gas, hydrochloric acid, phosphoric acid, aromatic sulfonic acids, and aliphatic sulfonic acids. The method for producing bisphenol according to claim 1, wherein the step (A) is carried out in the presence of an aromatic hydrocarbon and an aliphatic monoalcohol. 2. The method for producing bisphenol according to claim 1, wherein the slurry concentration of the bisphenol reaction liquid is 30% or more. The bisphenols include 2,2-bis(4-hydroxy-3-methylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, and 1,
The method for producing bisphenol according to any one of [1] to [7], further comprising at least one selected from 1-bis(4-hydroxy-3-methylphenyl)cyclohexane. A method for producing a polycarbonate resin, comprising producing a polycarbonate resin by using a bisphenol produced by the method for producing bisphenol according to any one of claims 1 to 8.