JP2007186501A - Method for producing bisphenol A - Google Patents

Abstract

In a method for producing bisphenol A (BPA) by reacting phenol (PH) and acetone (AC) in the presence of an ion exchange resin catalyst (catalyst), the reaction is stopped by periodic inspection or the like. In addition, the present invention provides a method for preventing the deterioration of the catalyst in the reactor and suppressing the decrease in the activity of the catalyst even after restarting the operation, and stably producing BPA over a long period of time.
A BPA manufacturing method including a reaction step in which a PH raw material and an AC raw material are supplied to a reactor filled with a catalyst to obtain a reaction liquid containing BPA. When stopping the reaction, (a) the operation of simultaneously stopping the supply of the AC raw material and the PH raw material after reducing the supply of the AC raw material to the reactor, or (b) stopping the supply of the AC raw material Then, any operation of stopping the supply of the PH raw material is included, and the water concentration in the liquid part in the reactor after the supply of the PH raw material is stopped is 0.5 to 2% by weight.
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Description

  The present invention relates to a method for producing bisphenol A. Specifically, in a method for producing bisphenol A by reacting a phenol raw material and an acetone raw material in the presence of an ion exchange resin catalyst, the reaction is stopped by periodic inspection or the like. Bisphenol A, which prevents the deterioration of the ion exchange resin catalyst in the reactor and suppresses the decrease in the activity of the ion exchange resin catalyst even after restarting operation, and can produce bisphenol A stably over a long period of time. It relates to a manufacturing method.

  Bisphenol A is usually produced by reacting phenol and acetone in the presence of an ion exchange resin catalyst. The reaction is continuously performed, and after a certain period of reaction, the operation is stopped by a periodic inspection and the reaction is resumed after the inspection is completed. The reaction liquid present in the reactor is maintained as it is during the period from the stop of the operation to the restart. At this time, the ion exchange resin catalyst is deteriorated, and a countermeasure for the problem has been studied. For example, when stopping the operation, the supply of the acetone raw material is stopped first, the supply of the phenol raw material is stopped after the acetone concentration in the reaction solution becomes a predetermined amount or less, and the ion exchange resin catalyst is put into the phenol liquid. A storage method is known (see, for example, Patent Document 1). In addition, a method is known in which a reaction liquid having a water concentration of 0.2% by weight or more is circulated and circulated in a reactor during operation stop (for example, see Patent Document 2). Although the above method has a certain effect on the deterioration of the ion exchange resin catalyst, the ion exchange resin catalyst still deteriorates, and the activity of the ion exchange resin catalyst is drastically decreased when the operation is continued for a long time after restarting the operation. In some cases, the method is not necessarily suitable for industrial scale production facilities.

JP 2002-255879 A JP-A-2005-247781

  The present invention has been made in view of the above circumstances, and its purpose is to stop the reaction by periodic inspection or the like in a method of producing bisphenol A by reacting phenol and acetone in the presence of an ion exchange resin catalyst. In this case, the deterioration of the ion exchange resin catalyst in the reactor can be prevented and the decrease in the activity of the ion exchange resin catalyst can be suppressed even after the operation is restarted, and bisphenol A can be produced stably over a long period of time. The object is to provide a method for producing bisphenol A.

  In order to solve the above problems, the present inventors have intensively studied. As a result, when stopping the operation, (a) after decreasing the supply of the acetone raw material to the reactor, the supply of the acetone raw material and the phenol raw material is simultaneously stopped. Or (b) an operation of stopping the supply of the phenol raw material after stopping the supply of the acetone raw material, and a predetermined amount in the reaction liquid existing in the reactor in the operation stop state. It is possible to prevent the deterioration of the ion exchange resin catalyst by containing the water, and to suppress the decrease in the activity of the ion exchange resin catalyst even after the restart of operation, and to produce bisphenol A stably over a long period of time. As a result, the present invention has been completed.

  That is, the gist of the present invention is a method for producing bisphenol A, which includes a reaction step of supplying a phenol raw material and an acetone raw material to a reactor filled with an ion exchange resin catalyst to obtain a reaction liquid containing bisphenol A, Including the operation of stopping and then restarting the reaction, and when stopping the reaction, (a) the operation of simultaneously stopping the supply of the acetone raw material and the phenol raw material after decreasing the supply of the acetone raw material to the reactor, or (B) includes any operation of stopping the supply of the phenol raw material after stopping the supply of the acetone raw material, and the water concentration in the liquid part in the reactor after the supply of the phenol raw material is stopped is 0 The present invention lies in a method for producing bisphenol A, characterized in that the content is from 5 to 2% by weight.

  According to the present invention, in the method of producing bisphenol A by reacting phenol and acetone in the presence of an ion exchange resin catalyst, the reaction of the ion exchange resin catalyst in the reactor is stopped when the reaction is stopped by periodic inspection or the like. While preventing the deterioration, the decrease in the activity of the ion exchange resin catalyst can be suppressed even after resuming operation, and bisphenol A can be produced stably over a long period of time.

  Hereinafter, the present invention will be described in detail. However, the description of the constituent elements described below is a representative example of embodiments of the present invention, and the present invention is not limited to these contents. The method for producing bisphenol A according to the present invention includes at least a reaction step of supplying a phenol raw material and an acetone raw material to a reactor filled with an ion exchange resin catalyst to obtain a reaction liquid containing bisphenol A.

  The reaction step in the present invention usually uses a reactor filled with an ion exchange resin as a catalyst. The phenol raw material and acetone raw material supplied to the reactor are reacted stoichiometrically with phenol excess. The molar ratio of phenol to acetone (phenol / acetone) is usually 3 to 30, and preferably 5 to 20. The liquid space velocity of the raw material mixture supplied to the reactor is usually 0.2 to 50 / h. The reaction temperature is usually 30 to 120 ° C, preferably 55 to 100 ° C. The reaction pressure is usually normal pressure to 600 kPa (absolute pressure).

  Said phenol raw material is a raw material which has phenol as a main component. Pure phenol may be used, but other compounds may include bisphenol A, its 2,4-isomer, chroman, trisphenol, a cyclic dimer of isopropenylphenol, and the like. The mother liquor separated in the recovery step for recovering bisphenol A, the reaction solution treated in the impurity treatment step, etc. can be used as they are, or a mixture thereof can be recycled. For example, the typical composition in the case of using the mother liquor separated in the recovery step for recovering bisphenol A is 12 to 30% by weight of bisphenol A and its isomer, and 70 to 88% by weight of phenol.

  Said acetone raw material is a raw material which has acetone as a main component. Pure acetone can be used, but it may contain impurities such as water. Acetone separated and recovered in the acetone circulation step can be used as it is, or a mixture with pure acetone can be recycled.

  The ion exchange resin for the catalyst is not particularly limited, and is preferably a strongly acidic cation exchange resin such as a sulfonic acid type, and more preferably a strongly acidic cation exchange resin is partially modified with a promoter such as a sulfur-containing amine compound. Resin is used. Examples of the sulfur-containing amine compound include 2- (4-pyridyl) ethanethiol, 2-mercaptoethylamine, 3-mercaptopropylamine, N, N-dimethyl-3-mercaptopropylamine, N, N-di-n-butyl. Common promoters used for the synthesis of bisphenol A, such as -4-mercaptobutylamine and 2,2-dimethylthiazolidine, can be mentioned. The usage-amount of a promoter is 2-30 mol% normally with respect to the acid group (sulfonic acid group in the case of a sulfonic acid type) in an acidic ion exchanger, Preferably it is 5-20 mol%. Also, a method of mixing a promoter such as alkyl mercaptan with a phenol raw material or an acetone raw material and supplying it to the reactor can be used.

  In the method for producing bisphenol A of the present invention, each step performed subsequent to the reaction step is not particularly limited, and for example, a known method can be employed. As each step performed subsequent to the reaction step, for example, a low boiling point component separation step for separating the reaction mixture obtained in the reaction step into a component containing bisphenol A and a low boiling point component containing unreacted acetone, A crystallization step of crystallizing bisphenol A as an adduct crystal with phenol from the components contained therein to obtain a slurry, and separating the slurry obtained in the crystallization step into crystals and a mother liquor to add bisphenol A to the phenol adduct A recovery step of recovering as a crystal of the product, a dephenolization step of obtaining bisphenol A by melting the adduct crystal obtained in the recovery step and removing phenol by means such as distillation, and at least one of the separated mother liquor Impurity treatment that separates light and heavy components by subjecting them to alkali heat treatment followed by distillation, and then recombining the light components Degree, unreacted acetone from the low boiling point components obtained in the low boiling point components separation step to separate and recover, like acetone circulation step of circulating the reaction step.

  In the production method of the present invention, after the above steps including the reaction step are continuously operated, the reaction is stopped by periodic inspection or the like. The reaction is stopped by (a) the operation of simultaneously stopping the supply of the acetone raw material and the phenol raw material after decreasing the supply of the acetone raw material to the reactor, or (b) the operation of stopping the supply of the phenol raw material after stopping the supply of the acetone raw material. The operation (b) is preferable because the acetone concentration at the outlet of the reactor can be rapidly reduced. In the operation (b), an operation of decreasing the supply of the acetone raw material continuously or stepwise may be performed prior to stopping the supply of the acetone raw material.

  The unreacted acetone in the reaction liquid reacts with phenol or reacts with the reaction liquid after the supply of the acetone raw material is reduced or the supply of the acetone raw material is stopped until the supply of the phenol raw material is stopped. It is discharged outside the vessel, and the acetone concentration gradually decreases. The timing for stopping the supply of the phenol raw material is not particularly limited, but is after the concentration of acetone at the outlet of the reactor is usually 0.1% by weight or less, preferably 0.05% by weight or less. In addition, it is preferable to use pure phenol as the phenol raw material used after the supply of the acetone raw material is reduced or after the supply of the acetone raw material is stopped.

  In the production method of the present invention, it is important that the water concentration in the liquid part in the reactor after the supply of the phenol raw material is stopped is 0.5 to 2% by weight, preferably 0.5 to 1% by weight. . When the water concentration is less than 0.5% by weight, the effect of suppressing the ion exchange resin catalyst deterioration is small, and when the operation is performed for a long time, the activity of the ion exchange resin catalyst is decreased. is necessary. On the other hand, if the water concentration exceeds 2% by weight, the water does not easily escape from the ion exchange resin catalyst layer when the operation is restarted. It is necessary to perform dehydration operation in advance. Therefore, it is necessary to keep the water concentration at 2% by weight or less, in which no dehydration operation is required and no significant decrease in activity is observed even after resumption of operation.

  The reaction solution immediately after the supply of the acetone raw material is stopped contains water produced by the reaction, but the water content decreases as the supply of the phenol raw material is reduced after the supply of the acetone raw material is reduced or stopped. . In order to set the moisture concentration in the reaction product within the specific range, it is preferable to add water to the phenol raw material or supply water directly to the reactor so that the water content falls within the above range.

  The water concentration in the liquid part in the reactor can be measured by, for example, a Karl Fischer type water concentration measuring device or gas chromatography, and is measured using this, or a calculated amount of water or The water concentration can be adjusted by a method such as adding hydrous phenol. The presence of water in the above range in the liquid part in the reactor can suppress the action of substances that degrade the ion exchange resin catalyst.

  The method for restarting the reaction is not particularly limited, such as a method of restarting by simultaneously supplying both the phenol raw material and the acetone raw material, a method of starting the supply of the acetone raw material after starting the supply of the phenol raw material, etc. Is mentioned. Among them, a method is preferable in which the phenol raw material is supplied while increasing step by step to a predetermined amount, and the supply of the acetone raw material is started immediately after the amount of the phenol raw material reaches the predetermined amount.

  EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to a following example, unless the summary is exceeded.

Examples 1-3, Comparative Examples 1-2:
In a fixed bed reactor (bottom radius = 0.2 m), 15 mol% of the sulfonic acid group of a sulfonic acid type cation exchange resin ("Diaion SK104H" manufactured by Mitsubishi Chemical Corporation) as a catalyst was 2- (4-pyridyl). ) 125 L of cation exchange resin modified with ethanethiol was charged. In a reactor, phenol raw material (feed amount = 95 kg / h) consisting of 86.3% by weight of phenol, 13.7% by weight of other compounds (including bisphenol A and its isomers) and 300 ppm by weight of water, Acetone raw material (supply amount = 3.5 kg / h) consisting of 99,7% by weight of acetone and 0.3% by weight of water was supplied, and the reaction was carried out at a reaction temperature of 58 ° C. for 180 days. The acetone conversion immediately after the start of the reaction was 98.5%, and the acetone conversion after 180 days of operation was 91.5%. Therefore, the supply of the acetone raw material to the reactor was stopped, and water was supplied to the reactor together with the phenol raw material at the supply amount shown in Table 1. Three hours after the supply of the acetone raw material was stopped, the acetone concentration of the effluent from the reactor was 0.05% by weight and the water concentration was the value shown in Table 1 in all cases. The supply of phenol raw materials and water was stopped. The quantitative analysis of water and acetone was performed with a gas chromatograph apparatus (GC-14B manufactured by Shimadzu Corporation, measurement was 220 ° C., and the carrier gas was He) equipped with a fused silica capillary column and a TCD detector.

  The reaction liquid in the reactor was not withdrawn, and was left at 75 ° C. for 30 days in a state where the catalyst was present in the reaction liquid. Thereafter, a phenol raw material (supply amount = 95 kg / h) and an acetone raw material (supply amount = 3.5 kg / h) having the same composition as before the shutdown were supplied to the reactor, and the reaction was resumed at a reaction temperature of 58 ° C. The acetone conversion immediately after restarting the reaction was the value shown in Table 1. After the reaction was resumed, the acetone conversion gradually decreased, and the acetone conversion was 80% over the days shown in Table 1.

  In Comparative Example 2, the acetone conversion immediately after the resumption of the reaction showed a low value. This is probably because a large amount of water still remained in the reactor. When the acetone conversion rate was measured 48 hours after the reaction was resumed, it was recovered to 90.5%. When the reaction was continued in the same manner as in the other examples, the acetone conversion rate was 80% after 135 days from the reaction restart. Reached.

Comparative Example 3:
The reaction was carried out using the same equipment, raw materials and conditions as in Example 1. The acetone conversion after operation for 180 days was 91.5%. Therefore, the supply of the phenol raw material and the acetone raw material was stopped simultaneously without reducing the supply of the acetone raw material. The acetone concentration in the effluent from the reactor immediately before the supply was stopped was 0.35% by weight, and the water concentration was 0.9% by weight. The reaction liquid in the reactor was not withdrawn, and was left at 75 ° C. for 30 days in a state where the catalyst was present in the reaction liquid. Thereafter, a phenol raw material (supply amount = 95 kg / h) and an acetone raw material (supply amount = 3.5 kg / h) were supplied to the reactor, and the reaction was resumed at a reaction temperature of 58 ° C. The acetone conversion immediately after resuming the reaction was 86.5%. After 100 days of operation, the acetone conversion was 80%.

  Although the present invention has been described with reference to the most practical and preferred embodiments at the present time, the invention is not limited to the embodiments disclosed herein. It should be understood that the present invention can be modified as appropriate without departing from the spirit or concept of the invention as read from the claims and the entire specification, and that such changes are also within the technical scope of the present invention. .

Claims (2)

  A method for producing bisphenol A, which comprises a reaction step of supplying a phenol raw material and an acetone raw material to a reactor filled with an ion exchange resin catalyst to obtain a reaction liquid containing bisphenol A, which is resumed after the reaction is once stopped. When stopping the reaction including the operation, (a) the operation of simultaneously stopping the supply of the acetone raw material and the phenol raw material after decreasing the supply of the acetone raw material to the reactor, or (b) the supply of the acetone raw material The operation includes any operation of stopping the supply of the phenol raw material after the stop, and the water concentration in the liquid part in the reactor after the supply of the phenol raw material is stopped is 0.5 to 2% by weight. The manufacturing method of bisphenol A characterized by the above-mentioned.   The method for producing bisphenol A according to claim 1, wherein the supply of the phenol raw material is stopped after the concentration of acetone at the outlet of the reactor becomes 0.1 wt% or less.