WO2015129640A1

WO2015129640A1 - Bisphenol a production method

Info

Publication number: WO2015129640A1
Application number: PCT/JP2015/055092
Authority: WO
Inventors: 岳志早川; 浩昭星野
Original assignee: 出光興産株式会社
Priority date: 2014-02-28
Filing date: 2015-02-23
Publication date: 2015-09-03
Also published as: JPWO2015129640A1; TW201538467A; KR20160127002A; RU2016134753A; RU2016134753A3; CN106061931A

Abstract

Provided is a bisphenol A production method in which, within one hour after granulating bisphenol A, isopropenylphenol concentration under ambient temperature conditions of 10-50˚C is monitored and the concentration is controlled to be no more than 150 ppm by mass.

Description

Method for producing bisphenol A

The present invention relates to a production method for producing high-quality bisphenol A, particularly bisphenol A having a good hue.

Polycarbonate resin produced from bisphenol A (hereinafter sometimes abbreviated as PC resin) has excellent transparency, heat resistance, low moisture absorption, and mechanical properties, so it is installed in mobile phones, portable game machines, car navigation systems, etc. Suitable for applications such as light guide plates. The polycarbonate material used for such applications as the light guide plate requires transparency (low YI).
When the bisphenol A is kept in a molten state at a high temperature during the production process, isopropenylphenol (hereinafter sometimes abbreviated as IPP) is formed in several hours. The production of isopropenylphenol causes coloring of the raw material bisphenol A, which deteriorates the hue, and the polycarbonate produced using this as a raw material has reduced transparency.
Therefore, in order to obtain a highly transparent polycarbonate, it is necessary to suppress coloring of the raw material bisphenol A (low APHA) by reducing the amount of isopropenylphenol.

In Patent Document 1, when bisphenol A is kept in a molten state at a high temperature, 4-isopropenylphenol is produced in a few hours, whereby the raw material bisphenol A starts to be colored. Is described as worsening. In order to suppress the production of 4-isopropenylphenol, Patent Document 1 discloses a production method that maintains a liquid molten state even at a low temperature by setting the ratio of bisphenol A / phenol to a specific range. Patent Document 1 describes a production method in which bisphenol A is used in the production of polycarbonate in a molten state without going through a granulation step. However, in the case of granulating molten bisphenol A and prilling it, There is no description.
Since the production of isopropenylphenol is largely caused by the acid flowing out from the main reaction step, it has been found that the installation of a effluent acid removal facility (filter, anion exchange resin, etc.) is effective. In Patent Document 2, a free acid removal step is provided to generate a colored substance present in the mother liquor or the isomerization treatment liquid, thereby removing the free acid that causes the deterioration of the hue of the product bisphenol A. A method for producing bisphenol A having excellent transparency (hue) is disclosed.
In Patent Document 3, it is also known that in the method for producing bisphenol A, decomposition of bisphenol A and production of 2,4′-bisphenol A are promoted due to free acid generated in the main reactor. The manufacturing method of bisphenol A which makes the free acid density | concentration in the manufacturing process of bisphenol A into the specific range is disclosed.
Patent Document 4 provides a method in which a crystallized adduct of bisphenol A and phenol is separated by a known method and then washed with purified phenol. In this washing treatment, the purified phenol is usually used at a ratio of 30 to 100 parts by mass with respect to 100 parts by mass of the adduct.

JP 2002-173530 A JP 2007-308408 A JP 2001-316313 A Japanese Patent Laid-Open No. 6-048970

As described in patent documents and the like, it is known that isopropenylphenol is a causative substance of hue deterioration. However, isopropenylphenol has a very high reactivity and easily changes to other components even at room temperature, which makes it difficult to set a concentration adjustment target in the production of bisphenol A. The present invention has been made to solve such a problem. By setting an isopropenyl phenol concentration adjustment target for bisphenol A obtained after granulation and controlling this concentration, bisphenol having a good hue is obtained. It aims at providing the manufacturing method which can manufacture A continuously.

The present inventors control the isopropenylphenol concentration within a specific range within 10 hours after the granulation of bisphenol A obtained by granulating a bisphenol A melt within 10 hours. Thus, it was found that bisphenol A having a good hue can be continuously produced.
That is, the present invention includes the following.
1. A method for producing bisphenol A, wherein the concentration of isopropenyl phenol under ambient temperature conditions of 10 to 50 ° C. is monitored within 1 hour after granulation of bisphenol A, and the concentration is controlled to 150 ppm by mass or less.
2. (1) a condensation reaction step in which an excess amount of phenol and acetone is subjected to a condensation reaction in the presence of an acidic catalyst;
(2) a crystallization / solid-liquid separation step of cooling the reaction mixture obtained in step (1) to crystallize an adduct of bisphenol A and phenol, and separating the adduct and mother liquor;
(3) Adduct decomposition step for removing phenol from the adduct of bisphenol A and phenol obtained in step (2) to obtain a bisphenol A melt, and (4) bisphenol A melt obtained in step (3). Granulating process,
In the method for producing bisphenol A having
A method for producing bisphenol A, wherein the concentration of isopropenyl phenol under ambient temperature conditions of 10 to 50 ° C. is monitored within 1 hour after granulation of bisphenol A, and the concentration is controlled to 150 ppm by mass or less.
3. (D) The method for producing bisphenol A according to 2, further comprising a concentration step of concentrating the reaction mixture obtained in step (1).
4). (A) The method for producing bisphenol A according to any one of 1 to 3, further comprising a free acid removing step, wherein the isopropenylphenol concentration is controlled by removing the free acid.
5. The concentration of the isopropenyl phenol is controlled by changing the amount of the washing liquid for washing the adduct crystal of bisphenol A and phenol in the crystallization / solid-liquid separation step (2). Production method.
6). 6. The method for producing bisphenol A according to 5, wherein the amount of the washing liquid is 10 to 100 parts by mass with respect to 100 parts by mass of an adduct crystal of bisphenol A and phenol.
7). (B) All or part of the mother liquor obtained in the crystallization / solid-liquid separation step (2) is isomerized with an isomerization catalyst, and the isomerization solution is condensed in the condensation reaction step (1) and / or concentrated. An isomerization step to be circulated in the step (D); and (C) a recovery step of recovering an adduct of bisphenol A and phenol from the remainder of the isomerization solution treated in the isomerization step (B). A method for producing bisphenol A according to any one of 1 to 6.

According to the method for producing bisphenol A of the present invention, the concentration of isopropenyl phenol is monitored within an hour after granulation of bisphenol A under an ambient temperature condition of 10 to 50 ° C., and the concentration is controlled to 150 ppm by mass or less. Thus, bisphenol A having a good hue can be produced.

The method for producing bisphenol A according to the present invention monitors the concentration of isopropenyl phenol under ambient temperature conditions of 10 to 50 ° C. within 1 hour after granulation of bisphenol A, and controls the concentration to 150 ppm by mass or less. Cost. The concentration of isopropenylphenol can be monitored by measuring, for example, by high performance liquid chromatography (hereinafter sometimes abbreviated as HPLC). If the isopropenyl phenol concentration exceeds 150 ppm by mass, the hue of bisphenol A obtained is deteriorated, resulting in a problem in quality. The isopropenyl phenol concentration is preferably controlled to 100 mass ppm or less, more preferably 50 mass ppm or less. Here, “after granulation” refers to the time when molten bisphenol A comes into contact with a cooling means such as a cooling gas.
Isopropenylphenol is represented by the following general formula (1).

In the present invention, the isopropenylphenol concentration of bisphenol A is monitored within 1 hour after granulation under ambient temperature conditions of 10 to 50 ° C., more preferably 15 to 40 ° C., more preferably 20 to 30 ° C. Since the isopropenylphenol concentration varies greatly depending on time and temperature, it is necessary to control the time and temperature within a specific range in order to monitor the isopropenylphenol concentration. More specifically, the condition for monitoring the isopropenyl phenol concentration in the present invention is an ambient temperature of 30 ° C. for 1 hour after granulation.

The increase or decrease in the isopropenyl phenol concentration of bisphenol A is largely related to the free acid concentration in the adduct decomposition process. In order to lower the isopropenylphenol concentration, for example, the free acid in the process is removed to reduce the free acid concentration in the adduct crystal of bisphenol A and phenol (hereinafter sometimes referred to as adduct crystal). The method and / or the method of removing the free acid adhering to a crystal | crystallization by wash | cleaning the adduct crystal | crystallization of bisphenol A and a phenol in a crystallization and solid-liquid separation process can be mentioned. By sufficiently reducing the concentration of the free acid contained in and / or adhering to the adduct crystal, the isopropenyl phenol concentration of bisphenol A obtained by decomposing the adduct crystal can be controlled to 150 mass ppm or less.
The concentration of isopropenylphenol can be controlled by providing a free acid removal step (A), which will be described later, as a method for removing the free acid in the process, if necessary.
Washing of the adduct crystal in the crystallization / solid-liquid separation step can be controlled as follows. That is, when the production facilities are the same and the production amount is constant, the isopropenylphenol concentration of bisphenol A under the ambient temperature condition of 10 to 50 ° C. is obtained in the crystallization step of the condensation reaction mixture within 1 hour after granulation. Depends on the particle size of the adduct crystal. As the adduct crystal particle size decreases, the specific surface area increases, the amount of impurities (free acids, isomers, etc.) adhering to the crystal obtained in the crystallization / solid-liquid separation process increases, and the free acid adhering to the crystal increases. This also increases the isopropenylphenol concentration. On the other hand, when the particle size of the adduct crystal is increased, the specific surface area is decreased, the amount of impurities adhering to the crystal obtained in the crystallization / solid-liquid separation step is decreased, and the isopropenylphenol concentration is decreased. That is, the isopropenyl phenol concentration depends on the particle size of the adduct crystal.
Here, the particle size of the adduct crystal is greatly influenced by the type and operating conditions of the crystallization equipment and the impurity concentration in the crystallization introduction liquid. In addition, in industrial production, it is said that strictly speaking, even if the production is performed under the same conditions, the particle size of the adduct crystal changes periodically. Therefore, it is difficult to directly control the particle size of the adduct crystal.
Monitoring the isopropenyl phenol concentration, which depends on the particle size of the adduct crystals or changes periodically, is very important in the production process of bisphenol A. According to the production method of the present invention, after granulation, when the isopropenyl phenol concentration of bisphenol A is measured under a predetermined condition, the isopropenyl phenol concentration is increased (that is, the particle size of the adduct crystal is reduced). The quality of the bisphenol A product can be kept good by changing the manufacturing process conditions so that the concentration of isopropenylphenol is reduced. Moreover, when the isopropenyl phenol concentration decreases (that is, the particle size of the adduct crystal increases), an unnecessary production process or the like can be stopped, which is industrially advantageous.
In the production of bisphenol A, a crystallization / solid-liquid separation process that can be purified at a low temperature is often employed in order to prevent thermal degradation and coloring of the product. In the crystallization / solid-liquid separation step, washing is often performed in addition to crystallization and solid-liquid separation. In particular, the cleaning performance greatly affects product quality in the cleaning operation. This cleaning performance is greatly related not only to the amount of cleaning solution but also to the crystal shape obtained by the crystallization operation. However, it is very difficult to confirm the crystal grain size in a normal manufacturing apparatus. In addition, the crystal grain size distribution depends on the stirring speed and the production equipment volume. Furthermore, the grain size of the crystals can change periodically. From the above, it is important to adjust the amount of cleaning liquid each time while confirming the properties of the desired bisphenol A product in the manufacturing process in order to achieve optimal cleaning results and obtain excellent product quality. Come.

When granulating bisphenol A in the production method of the present invention, a granulator for granulating a general bisphenol A melt can be used. For example, it is possible to use a granulating tower in which a nozzle plate having a large number of holes, in which bisphenol A melt is used as droplets, is installed at the top of the tower and a duct for blowing cooling gas is provided at the bottom of the tower. The bisphenol A melt is fed to the top of the granulation tower, and the bisphenol A melt is sprayed in a shower form from a number of holes provided in the nozzle plate installed at the top of the tower. The sprayed molten liquid is cooled by a circulating gas rising from the bottom of the granulation tower, and a particulate solid called prill from the bottom of the tower (referring to bisphenol A obtained by granulation is called “bisphenol A prill”) The product bisphenol A is extracted from the granulation delivery outlet. As the nozzle plate, a metal plate or the like provided with a large number of holes is used and can be heated by an electric heater, steam, or the like in order to prevent bisphenol A from solidifying.

The temperature of the bisphenol A melt is preferably 157 to 200 ° C. If the temperature of the bisphenol A melt is lower than 157 ° C., the melt may solidify when the bisphenol A melt is introduced into the granulation step, and the piping may be blocked. Moreover, when it exceeds 200 degreeC, there exists a possibility that decomposition | disassembly of bisphenol A may be accelerated | stimulated and it may color. The temperature of the bisphenol A melt is more preferably 160 to 180 ° C.

The granulation nozzle is, for example, a plate provided with a nozzle. In the present invention, the average particle diameter is adjusted by setting the nozzle hole diameter (diameter) to preferably 0.3 to 1.0 mm, more preferably 0.4 to 0.7 mm, and still more preferably 0.5 to 0.6 mm. Bisphenol A prill having a diameter of about 0.5 to 1.5 mm can be obtained.
In the present invention, the flow rate of the bisphenol A melt flowing out from the granulation nozzle is preferably 0.5 to 1.8 m / sec. If the outflow speed of the bisphenol A melt is 0.5 m / second or more, the bisphenol A prill obtained by combining the droplets of the bisphenol A melt is within the above particle size range. When the flow rate of the bisphenol A melt is 1.8 m / sec or less, the size of the bisphenol A prill obtained is uniform. The outflow rate of the bisphenol A melt is preferably 1.0 to 1.8 m / sec, more preferably 1.4 to 1.8 m / sec.

The cooling time for the droplets of the bisphenol A melt is usually several tens of seconds to 1 minute. The height of the granulation tower is determined by the cooling time of the bisphenol A melt droplets, but is usually about 10 to 50 m.

In one form of the method for producing bisphenol A of the present invention, (1) a condensation reaction step in which an excess amount of phenol and acetone are subjected to a condensation reaction in the presence of an acidic catalyst, (2) a reaction obtained in step (1) Crystallization / solid-liquid separation step of crystallizing the adduct of bisphenol A and phenol by cooling the mixture and separating the adduct and mother liquor, (3) Bisphenol A and phenol obtained in step (2) The adduct decomposition | disassembly process which removes phenol from the adduct and makes a bisphenol A melt, and the granulation process which granulates the bisphenol A melt obtained by (4) process (3) may be provided.
Moreover, you may have further the concentration process which concentrates the reaction mixture obtained by (D) process (1) between (1) condensation reaction process and (2) crystallization and solid-liquid separation process.
Each step will be described below.

(1) Condensation reaction step In this step, the raw material phenol and acetone are reacted stoichiometrically in an excess of phenol. The molar ratio of phenol to acetone is usually in the range of phenol / acetone = 3 to 30, preferably in the range of 5 to 20. The reaction temperature is usually 50 to 100 ° C., and the reaction pressure is usually normal pressure to 1.5 MPa, preferably normal pressure to 0.6 MPa. As the catalyst, a strongly acidic cation exchange resin is usually used. The strong acid cation exchange resins, sulfonic acid functional group (RSO ₃ ^- H ⁺⁾ that have, and examples of the weakly acidic cation exchange resin carboxylic acid group in the functional group (R-COO ^- H ⁺⁾ Phosphonic acid group (RP (O) (O ⁻ H ⁺ ) ₂ ), phosphinic acid group (R—PH (O) (O ⁻ H ⁺ )), arsenite group (R—OAsO ⁻ H ⁺ ) And those having a phenoxide group (R—C ₆ H ₄ O ^— H ⁺ ) are known and can also be used in the present invention. A sulfonic acid type strongly acidic cation exchange resin having a sulfonic acid group as a functional group is common and preferred.
Examples of commercially available ion exchange resins include Diaion SK104H manufactured by Mitsubishi Chemical Corporation, Levachit MP-62 manufactured by Bayer, and Amberlyst A26 manufactured by R & H, which can also be used in the present invention.
Furthermore, a catalyst obtained by neutralizing a part of the strongly acidic cation exchange resin catalyst with a promoter such as mercaptoalkylamine can also be used. For example, 2-mercaptoethylamine, 3-mercaptopropylamine, N, N-dimethyl-3-mercaptopropylamine, N, N-di-n-butyl-4-mercaptobutylamine, 2,2-dimethylthiazolidine, etc. Examples thereof include those in which 5 to 30 mol% of the groups are neutralized.

The condensation reaction of the raw material liquid of phenol and acetone is carried out by a fixed bed flow system, which is a continuous system and a forced flow system, or a suspension bed batch system. In the case of a fixed bed flow system, the liquid space velocity (LHSV) of the raw material liquid supplied to the reactor is about 0.1 to 50 hr ⁻¹ . In addition, when the suspension bed batch method is used, although depending on the reaction temperature and reaction pressure, generally, a resin catalyst amount in the range of 20 to 100% by mass with respect to the raw material liquid is used, and the reaction time is 0. About 5 to 5 hours.

(D) Concentration step The production method of the present invention may optionally have a concentration step (D) between (1) the condensation reaction step and (2) the crystallization / solid-liquid separation step. The reaction mixture from the above (1) condensation reaction step can usually be concentrated in a two-step process. In the first concentration step, unreacted acetone, reaction product water, and the like are removed by a method such as vacuum distillation. The vacuum distillation is usually carried out at a temperature of about 30 to 180 ° C. and a pressure of about 13 to 67 kPa.
Subsequently, in the second concentration step, phenol is distilled off and the concentration of bisphenol A is adjusted. The concentration of bisphenol A at this time is preferably about 20 to 60% by mass. When the concentration of bisphenol A is lower than 20% by mass, the yield is low. On the other hand, if it exceeds 60% by mass, the solidification temperature of bisphenol A becomes high, and it becomes easy to solidify, which causes a problem that it cannot be transferred. Accordingly, the concentration is usually adjusted by pre-concentrating the reaction mixture in the first concentration step. This second concentration step is usually preferably carried out under conditions of a temperature of about 70 to 140 ° C. and a pressure of about 4 to 40 kPa.

(2) Crystallization / Solid-Liquid Separation Step The reaction mixture from the condensation reaction step (1) or the concentrate from the concentration step (D) is usually cooled from about 70 to 140 ° C. to about 35 to 60 ° C., An adduct of bisphenol A and phenol crystallizes into a slurry. The cooling of the concentrate is removed by latent heat due to evaporation of water added to the external heat exchanger or the crystallization can. Next, the slurry liquid is solid-liquid separated. The composition of the mother liquor obtained in this crystallization / solid-liquid separation step is usually 65 to 85% by mass of phenol, 10 to 20% by mass of bisphenol A, and 5 to 15 by-products such as 2,4′-isomer. % By mass.
The adduct crystals of bisphenol A and phenol separated by solid-liquid separation of the slurry-like reaction mixture are then sent to an adduct decomposition step to remove the phenol, whereby high purity bisphenol A is obtained.

The solid component mainly composed of adduct crystals that have been filtered and deposited on the filter surface of the solid-liquid separator is subjected to washing with a washing liquid. As the cleaning liquid, in addition to phenol recovered by evaporation, raw material phenol, water, water-phenol mixed liquid, the same one as the saturated phenol solution of bisphenol A can be used. The amount of the cleaning liquid is one means for controlling the isopropenylphenol concentration of the present invention, and will be described later.
The mother liquor obtained in the crystallization / solid-liquid separation step (2) is recycled to the condensation reaction step (1) and / or the concentration step (D) or further subjected to the isomerization step (B) described later. When provided, the total amount of the mother liquor or a part thereof is supplied to the isomerization step (B).
The adduct crystal may be redissolved after crystallization and solid-liquid separation, and crystallization and solid-liquid separation may be repeated again. By repeating this crystallization and solid-liquid separation in multiple stages, impurities taken into the adduct crystal are sequentially reduced. In this case, as a washing solution for washing a redissolved solution and a solid component mainly composed of adduct crystals obtained by solid-liquid separation, evaporated and recovered phenol, raw material phenol, water, water-phenol mixed solution In addition, the same solution as the saturated phenol solution of bisphenol A can be used in each stage. The amount of the cleaning liquid at the time of recrystallization is also one means for controlling the concentration of isopropenylphenol of the present invention, which will be described later. Further, the mother liquor obtained by recrystallization and solid-liquid separation can be recycled to the crystallization process described above.

(3) Adduct decomposition step In the crystallization / solid-liquid separation step (2), the adduct crystal recovered by solid-liquid separation removes phenol in the adduct decomposition step to become high-purity bisphenol A. For example, generally, the adduct crystal is decomposed into bisphenol A and phenol by heating and melting at about 100 to 160 ° C., and most of the phenol is removed from the melt with an evaporator, and steam is further removed. By removing residual phenol by stripping, a bisphenol A melt is obtained.

(4) Granulation step The bisphenol A melt obtained by the adduct decomposition step (3) is granulated in this step by the granulation method described above. That is, a general bisphenol A melt such as a granulation tower having a nozzle plate having a large number of holes for droplets of bisphenol A melt at the top and a duct for blowing a cooling gas at the bottom of the tower. It can granulate using the granulator which granulates a liquid. The temperature of the bisphenol A melt is preferably 157 to 200 ° C., the nozzle hole diameter (diameter) is preferably 0.3 to 1.0 mm, and the outflow rate of the bisphenol A melt flowing out of the granulation nozzle is preferably Is 0.5 to 1.8 m / sec. The height of the granulation tower is usually about 10 to 50 m. The preferable reason and the more preferable range are as described above.
In the present invention, within 1 hour after granulation of bisphenol A, the isopropenylphenol concentration is monitored under an ambient temperature condition of 10 to 50 ° C., and the production process is controlled so that the concentration is 150 mass ppm or less. Cost.

The free acid is removed as one means of controlling the production process so that the concentration of isopropenylphenol under the ambient temperature condition of 10 to 50 ° C. is less than 150 ppm by mass within 1 hour after granulation of bisphenol A. It can mention providing a free acid removal process (A) in the manufacturing method of bisphenol A of the present invention. Therefore, the method for producing bisphenol A of the present invention may have the following free acid removal step (A).

(A) Free acid removal process The installation place of the free acid removal process (A) is not particularly limited, but before the raw material phenol and the condensation reaction process (1) (inlet liquid), after the condensation reaction process (1) (outlet liquid) ), And the crystallization mother liquor obtained after the crystallization / mother liquor separation step (2), preferably the crystallization mother liquor obtained after the crystallization / solid-liquid separation step (2). Is done.
In the free acid removal step of the present invention, an acid adsorbent or an anion exchange resin can be used as the acid removal means. As the acid adsorbent, for example, an alkali metal compound / alkaline earth metal compound can be used as disclosed in JP-A-11-152240. As the anion exchange resin, a strong basic ion exchange resin and a weak basic ion exchange resin can be used.

As the strongly basic anion exchange resin, having a quaternary ammonium base ^{^{(R-N + R 1 R}} 2 R 3) or a tertiary sulfonium group to ^{^{(R-S + R 1 R}} 2) as a functional group Can be used.
Examples of commercially available anion exchange resins include Diaion WA-20, 21, and 30 manufactured by Mitsubishi Chemical Corporation, and Amberlyst A21 manufactured by R & H, which can also be used in the present invention.

In the production method of the present invention, the raw phenol or mother liquor is removed from the free acid removal step (A) within 1 hour after granulation of bisphenol A while monitoring the concentration of isopropenylphenol under ambient temperature conditions of 10 to 50 ° C. ) Or not. That is, when the isopropenyl phenol concentration of bisphenol A obtained after granulation begins to exceed 150 ppm by mass, the raw acid phenol and mother liquor are removed through the free acid removal step (A). To lower the isopropenyl phenol concentration. Moreover, when the isopropenyl phenol concentration under the above conditions is 150 ppm by mass or less due to an increase in the particle size of the adduct crystal, etc., the raw acid phenol or mother liquor is not passed through the free acid removal step (A). The manufacturing process can proceed.
Thus, by monitoring the isopropenylphenol concentration under predetermined conditions and determining whether or not the free acid removal step is necessary, bisphenol A having a low isopropenylphenol concentration and good quality can be obtained. If the isopropenylphenol concentration is 150 mass ppm or less, the free acid removal step can be omitted, and the production amount per unit time can be increased when producing bisphenol A continuously, which is industrially advantageous. .

Within one hour after granulation of bisphenol A, as another means of controlling the production process so that the concentration of isopropenylphenol under ambient temperature of 10 to 50 ° C. is 150 ppm by mass or less, crystallization / solid liquid In the separation step (2), when the solid component mainly composed of the adduct crystal that has been filtered and deposited on the filter surface of the solid-liquid separator described above is washed, and when the adduct crystal is recrystallized, It can be mentioned that the amount of the cleaning liquid at the time of cleaning is changed. As described above, as the cleaning liquid, purified phenol, phenol recovered by evaporation, raw material phenol, water, water-phenol mixed solution, and the same saturated phenol solution of bisphenol A can be used as described above.

The amount of the washing liquid is usually preferably 10 to 100 parts by mass, more preferably 15 to 85 parts by mass with respect to 100 parts by mass of the adduct crystal obtained in the crystallization / solid-liquid separation step (2) on a mass basis. More preferably, it is 20 to 75 parts by mass. When the amount of the cleaning liquid is less than 10 parts by mass with respect to 100 parts by mass of the adduct crystal, the cleaning efficiency is not preferable. If the amount of the cleaning liquid exceeds 100 parts by mass, the remelting loss of the adduct crystals tends to increase, and it is not preferable from the viewpoint of circulation, recovery, and reuse of the cleaning liquid.

In the method for producing bisphenol A of the present invention, when the amount of the cleaning liquid in the crystallization / solid-liquid separation step (2) is changed as a process control means, the amount of the cleaning liquid is determined as follows.
In the production method of the present invention, the amount of the cleaning solution is changed within the above range while monitoring the isopropenylphenol concentration under the ambient temperature condition of 10 to 50 ° C. within 1 hour after the granulation of bisphenol A. That is, when the concentration of isopropenyl phenol under the above conditions of bisphenol A obtained after granulation starts to exceed 150 ppm by mass, the concentration of isopropenyl phenol is increased by increasing the amount of the cleaning solution within the above range and strengthening the cleaning. Perform the operation to lower. Further, when the concentration of isopropenylphenol under the above conditions becomes 150 ppm by mass or less due to an increase in the particle size of the adduct crystals, the amount of the cleaning liquid is reduced within the above range.
Thus, by controlling the washing by monitoring the isopropenyl phenol concentration under the ambient temperature condition of 10 to 50 ° C. within 1 hour after the granulation of bisphenol A, the bisphenol A has a low isopropenyl phenol concentration and good quality. Can be obtained. If the isopropenylphenol concentration is 150 mass ppm or less, unnecessary washing can be stopped, and this is industrially advantageous when continuously producing bisphenol A.

In another embodiment, the method for producing bisphenol A according to the present invention comprises isomerizing a total amount or a part of the mother liquor obtained in the crystallization / solid-liquid separation step (2) with an isomerization catalyst. There may be provided an isomerization step (B) in which the crystallization treatment liquid is circulated to the condensation reaction step (1) and / or the concentration step (D).

(B) Isomerization process The whole or part of the liquid phase part (mother liquor) obtained in the crystallization / solid-liquid separation process (2) is supplied to the isomerization process (B), and reaction by-products in the mother liquor (2 , 4′-isomer etc.) can be isomerized. The mother liquor obtained in the crystallization / solid-liquid separation step (2) not supplied to the isomerization step (B) is recycled to the condensation reaction step (1) and / or the concentration step (D) as described above. Is done.
The isomerization treatment is preferably carried out by a fixed bed flow system in which the mother liquor is supplied continuously and in a forced flow manner to a fixed bed reactor (isomerization vessel) filled with a strongly acidic cation exchange resin. As the strong acid cation exchange resin, for example, a sulfonic acid type cation exchange resin can be used. The isomerization reaction temperature is preferably in the range of 50 to 100 ° C, more preferably 70 to 80 ° C. By setting the temperature to 50 ° C. or higher, solidification of bisphenol A in the mother liquor is avoided, and by setting the temperature to 100 ° C. or lower, problems of product quality deterioration due to elimination of sulfonic acid from the catalyst and acid decomposition of bisphenol A are avoided. .
In the case of a fixed bed isomerization reactor, the liquid hourly space velocity (LHSV) is usually preferably 0.1 to 50 hr ⁻¹ , more preferably 0.15 to 25 hr ⁻¹ , still more preferably 0.2 to 0.4 hr ^{−. 1} . By adjusting LHSV to 0.1 hr ⁻¹ or more, the amount of by-products is reduced, and by setting it to 50 hr ⁻¹ or less, a high conversion can be obtained.
Most of the isomerization treatment liquid after the isomerization treatment is recycled to the condensation reaction step (1) and / or the concentration step (D), preferably to the concentration step (D). Further, if necessary, a part of the isomerization treatment liquid is extracted to prevent accumulation of impurities and is sent to the following recovery step (C) as an exhaust liquid.

(C) Recovery process Some of the isomerization solution sent from the isomerization process (B) contains about 15 to 20% by mass of bisphenol A and 5 to 5 of by-products such as 2,4′-isomer. About 10% by mass is contained. After concentrating the isomerization solution, the adduct crystal of bisphenol A and phenol is crystallized by cooling in the presence of phenol. After solid-liquid separation, the adduct crystal is melted and then recycled to the concentration step (D) and / or the crystallization / solid-liquid separation step (2). The mother liquor after the solid-liquid separation is treated after recovering phenol.

Examples of other methods for controlling the concentration of isopropenyl phenol include the following methods.
As described above, the isopropenylphenol concentration can vary depending on the particle size of the adduct crystal obtained in the crystallization / solid-liquid separation step. In general, in crystal growth, it is presumed that an increase in production supersaturation contributes to an increase in average crystal diameter. Therefore, as one method of increasing the particle size of adduct crystals in order to reduce the isopropenylphenol concentration, the degree of operation supersaturation in the bisphenol A production apparatus (ΔC = P (crystal production amount) / G (circulation amount in the tank)) ) May be adjusted to reduce the manufacturing process.

As described above, according to the production method of the present invention, the concentration of isopropenylphenol under ambient temperature conditions of 10 to 50 ° C. is monitored within 1 hour after granulation of bisphenol A, and the concentration is controlled to 150 ppm by mass or less. Thus, bisphenol A having a good hue (low APHA) can be produced. APHA used for the evaluation of hue is, for example, JIS K-4101 or ASTM D-1686 (Japan Oil Chemist's Society), Standard Methods for the Analysis of Fats, Oils and Related Materials)). APHA is preferably 50 or less, more preferably 40 or less, and still more preferably 30 or less.

Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. In Examples and Comparative Examples, a method for controlling the concentration of isopropenylphenol under an ambient temperature of 10 to 50 ° C. within 1 hour after granulation of bisphenol A to 150 ppm by mass or less is examined.

Example 1
A fixed bed reaction column packed with 20 mol% partially neutralized cation exchange resin [Mitsubishi Chemical Co., Ltd., “Diaion SK104H”] with 2-mercaptoethylamine was charged with phenol at a molar ratio of 10: 1. Acetone was continuously passed through LHSV 3 hr ⁻¹ and the reaction was performed at 75 ° C. (condensation reaction step (1)). The resulting reaction mixture was introduced into a vacuum distillation tower, distilled under reduced pressure at a tower bottom temperature of 170 ° C. and a pressure of 67 kPa to remove unreacted acetone, reaction product water, and the like, and further at a temperature of 130 ° C. and a pressure of 14 kPa. Under reduced pressure, the phenol was distilled off and concentrated until the bisphenol A concentration became 40% by mass to obtain a concentrated solution of phenol / bisphenol A (concentration step (D)).
Next, crystallization was performed by adding water to the obtained concentrated liquid and maintaining at 45 ° C. in a crystallization tank reduced in pressure to 2 kPa (15 Torr), and the obtained slurry solution was filtered with a horizontal belt filter. Then, it wash | cleaned using raw material phenol in the ratio of 40 mass parts with respect to 100 mass parts of obtained adduct crystals. The obtained adduct crystal was subjected to a recrystallization operation described later (crystallization / solid-liquid separation step (2)).
Since the liquid filtered through the horizontal belt filter (crystallization mother liquor) contains 5% by mass of water, the concentration of water in the mother liquor was adjusted to 0.5% by mass using a distillation tower. Prior to isomerization of the prepared mother liquor, it was sent to a free acid removal tower packed with a weakly basic anion exchange resin (R & H “Amberlyst A21”), and the reaction temperature was 75 ° C. and LHSV = 1 hr ⁻¹ . (Free acid removal step (A)). The whole amount of the mother liquor from which free acid has been removed is supplied to an isomerization reactor filled with a cation exchange resin (manufactured by Mitsubishi Chemical Corporation, “Diaion SK104H”) at a reaction temperature of 75 ° C. and LHSV = 1 hr ⁻¹ . (Isomerization treatment step (B)). In order to adjust the bisphenol A concentration to 40% by mass, 80% of the isomerized mother liquor is circulated upstream of the vacuum distillation tower in the concentration step (D), and 20% is sent to the recovery step (C). did.
To the adduct crystal obtained by filtration through the horizontal belt filter, the evaporated and recovered phenol and the mother liquor from the recrystallization step are added and heated to 90 ° C. to prepare a solution containing 45% by mass of bisphenol A. And filtered. Water was again added to the obtained crystal, and recrystallization was performed at 5.33 kPa (40 Torr) at 50 ° C. The obtained slurry solution was supplied to a two-stage extrusion centrifuge (400G), and washed with 40 parts by mass of raw material phenol with respect to 100 parts by mass of adduct crystals to obtain wet adduct crystals. The obtained wet adduct crystal was heated and melted at 130 ° C., dephenolized, and then granulated in a spray granulation tower to obtain bisphenol A (prill) as a product.
The bisphenol A obtained after granulation is stored at room temperature (30 ° C.), and bisphenol A that has passed 1 hour, 2 hours, 8 hours, 24 hours, 48 hours after granulation is subjected to high performance liquid chromatography. Analysis. In this embodiment, the time when the bisphenol A melt flows out of the granulation nozzle is defined as 0 hour after granulation. For the analysis, a high performance liquid chromatograph (Waters, model: 2695, column: Inertsil (registered trademark) ODS-3V GL Sciences) was used. After being kept in a 25% by mass acetonitrile aqueous solution as a mobile phase for 45 minutes, it was analyzed with a gradient of 3.5% by mass / min. After reaching 100% by mass acetonitrile, it was held for 5 minutes. The sample injection volume was 5.0 μL, the column temperature was 40 ° C., the flow rate was 1.0 mL / min, and the analysis wavelength was 277 nm.
As a result of HPLC measurement, the IPP concentrations were 40 (after granulation (hereinafter the same) for 1 hour), 36 (2 hours), 32 (8 hours), 26 (24 hours), and 23 (48 hours) mass ppm, respectively. . The results are shown in Table 1.
Moreover, hue evaluation of bisphenol A was performed by APHA evaluation. APHA was measured by the method defined in JIS K-4101. Specifically, bisphenol A prill was heated at 220 ° C. for 40 minutes in an air atmosphere, and the hue was visually evaluated using an APHA standard color. All the results were APHA10. The results are shown in Table 1.
Moreover, using bisphenol A obtained in the present Example, polycarbonate resin was manufactured according to the following manufacture examples, and YI was measured.

Production Example: Production of bisphenol A polycarbonate resin Polycarbonate oligomer synthesis step To a 5.6 mass% aqueous sodium hydroxide solution, 2000 mass ppm of sodium dithionite is added to bisphenol A (hereinafter sometimes abbreviated as BPA) which is dissolved later, and the BPA concentration is added thereto. The BPA obtained in this example was dissolved so that the amount of the solution was 13.5% by mass to prepare an aqueous sodium hydroxide solution of BPA. This BPA aqueous solution of sodium hydroxide 40 L / hr, methylene chloride 15 L / hr and phosgene 4.0 kg / hr were continuously passed through a tubular reactor having an inner diameter of 6 mm and a tube length of 30 m. The tubular reactor had a jacket portion, and the temperature of the reaction solution was kept at 40 ° C. or lower by passing cooling water through the jacket.
The reaction solution exiting the tubular reactor was continuously introduced into a 40-liter baffled tank reactor equipped with a receding blade, and further BPA sodium hydroxide aqueous solution 2.8 L / hr, 25 mass%. Sodium hydroxide aqueous solution 0.07L / hr, water 17L / hr, and 1 mass% triethylamine aqueous solution 0.64L / hr were added, and reaction was performed.
The reaction liquid overflowing from the tank reactor was continuously extracted and allowed to stand to separate and remove the aqueous phase, and the methylene chloride phase was collected. The polycarbonate oligomer obtained had a concentration of 325 g / L and a chloroformate group concentration of 0.77 mol / L.

2. Polymerization process of polycarbonate After the temperature of the cooling solvent in a 50 L tank reactor equipped with baffle plates, paddle type stirring blades and a cooling jacket became 20 ° C. or less, 15 L of oligomer solution, 8.9 L of methylene chloride, p-tert -192 g of butylphenol, 0.7 mL of triethylamine, and an aqueous solution of BPA in sodium hydroxide (1185 g of BPA was dissolved in an aqueous solution of 647 g of NaOH and 2000 mass ppm of sodium dithionite dissolved in 9.5 L of BPA. And the polymerization reaction was carried out for 30 minutes. Thereafter, 0.8 mL of triethylamine was added and the mixture was further stirred for 30 minutes.
After addition of 15 L of methylene chloride for dilution, the organic phase was isolated by separating into an organic phase containing polycarbonate resin and an aqueous phase containing excess BPA and NaOH. The obtained methylene chloride solution of polycarbonate resin was washed successively with 15% by volume of 0.03 mol / L · NaOH aqueous solution and 0.2 mol / L hydrochloric acid, and then the electric conductivity in the aqueous phase after washing. Was repeatedly washed with pure water until 0.05 μS / m or less. The dichloromethane solution of the polycarbonate resin obtained by washing was concentrated and pulverized, and the obtained flakes were dried at 100 ° C. under reduced pressure to obtain a bisphenol A polycarbonate resin.

The YI value of the produced polycarbonate resin was measured as follows.
The resin flakes obtained above are pelletized, and the resin pellets are dried at 110 ° C. for 5 hours, and then plasticized at 300 ° C. using an injection molding machine (product name: FS80S-12ASE, manufactured by Nissei Plastic Industry Co., Ltd.). Then, it was allowed to stay in the cylinder for 15 seconds to form a molded product having a thickness of 3.2 mm and a square of 60 mm, and this test piece was used with a spectral color difference meter SE-2000 manufactured by Nippon Denshoku Industries Co., Ltd. and JIS K-7105. Measured by a method based on The results are shown in Table 2.

Example 2
100 parts by weight of the adduct crystal obtained in the crystallization / solid-liquid separation step (2) was washed with phenol recovered by evaporation at a ratio of 5 parts by weight, and the adduct crystal was recrystallized. At this time, bisphenol A was produced in the same manner as in Example 1 except that 100 parts by mass of the adduct crystal was washed with 5 parts by mass of raw material phenol.
The bisphenol A obtained after granulation was stored under room temperature conditions (30 ° C.), and bisphenol A that had passed 1 hour, 2 hours, 8 hours, 24 hours, and 48 hours after granulation was the same as in Example 1. The analysis was performed by high performance liquid chromatography. As a result of the measurement, IPP concentrations were 99 (after granulation (hereinafter the same) for 1 hour), 92 (2 hours), 81 (8 hours), 63 (24 hours), and 56 (48 hours) mass ppm, respectively. The results are shown in Table 1.
The obtained bisphenol A was also evaluated for hue by APHA as in Example 1. All the results were APHA20. The results are shown in Table 1.
A polycarbonate resin was produced according to the production example in the same manner as in Example 1 except that bisphenol A obtained in this example was used, and the YI value was measured in the same manner as in Example 1. The results are shown in Table 2.

Example 3
Except that the free acid was not removed, the same operation as in Example 1 was performed to produce bisphenol A. The obtained bisphenol A was stored under room temperature conditions (30 ° C.), and bisphenol A that had passed 1 hour, 2 hours, 8 hours, 24 hours, and 48 hours after granulation was subjected to a high-speed liquid in the same manner as in Example 1. Analysis was performed by chromatography. As a result of the measurement, the IPP concentrations were 150 (after granulation (hereinafter the same) for 1 hour), 133 (2 hours), 121 (8 hours), 94 (24 hours), and 84 (48 hours) mass ppm, respectively. The results are shown in Table 1.
The obtained bisphenol A was also evaluated for hue by APHA as in Example 1. All the results were APHA35. The results are shown in Table 1.
Further, a polycarbonate was produced according to the production example in the same manner as in Example 1 except that bisphenol A obtained in this example was used, and a molded article was prepared in the same manner as in Example 1, and the YI value was measured. The results are shown in Table 2.

Comparative Example 1
A fixed bed reaction column packed with 20 mol% partially neutralized cation exchange resin [Made by Mitsubishi Chemical Co., Ltd., “Diaion SK104H”] with 2-mercaptoethylamine was mixed with phenol having a molar ratio of 10: 1. Acetone was continuously passed through LHSV 3 hr ⁻¹ and reacted at 75 ° C. The resulting reaction mixture was introduced into a vacuum distillation tower, distilled under reduced pressure at a tower bottom temperature of 170 ° C. and a pressure of 67 kPa to remove unreacted acetone, reaction product water, and the like, and further at a temperature of 130 ° C. and a pressure of 14 kPa. Under reduced pressure, the phenol was distilled off and concentrated until the bisphenol A concentration became 40% by mass to obtain a phenol / bisphenol A concentrate.
Next, crystallization was performed by adding water to the obtained concentrated liquid and maintaining at 45 ° C. in a crystallization tank reduced in pressure to 2 kPa (15 Torr), and the obtained slurry solution was filtered with a horizontal belt filter. Thereafter, the obtained adduct crystal was washed with phenol collected by evaporation at a ratio of 5 parts by mass with respect to 100 parts by mass of the adduct. The obtained adduct crystal was subjected to a recrystallization operation described later.
Since the liquid filtered through the horizontal belt filter (crystallization mother liquor) contains 5% by mass of water, the concentration of water in the mother liquor was adjusted to 0.5% by mass using a distillation tower. The mother liquor with adjusted water concentration was charged into an isomerization reactor filled with a cation exchange resin (Made by Mitsubishi Chemical Corporation, “Diaion SK104H”) at a reaction temperature of 75 ° C. and LHSV = 1 hr ⁻¹ . Supplied.
In order to adjust the bisphenol A concentration to 40% by mass, 80% of the isomerized mother liquor is circulated upstream of the vacuum distillation tower in the concentration step (D), and 20% is sent to the recovery step (C). Liquid.
To the adduct crystal obtained by filtration through a horizontal belt filter, the evaporated and recovered phenol and the mother liquor from the recrystallization step are added and heated to 90 ° C. to prepare a solution containing 45% by mass of bisphenol A. And filtered. Water was added to the obtained crystal again, and recrystallization was performed at 5.33 kPa (40 Torr) at 50 ° C., and the resulting slurry solution was supplied to a two-stage extrusion centrifuge (400 G). The wet adduct crystal was obtained by washing with 100 parts by mass of the raw material phenol in a proportion of 5 parts by mass. The obtained wet adduct crystal was heated and melted at 130 ° C., dephenolized, and granulated in a spray granulation tower to obtain bisphenol A as a product.
The bisphenol A obtained after granulation was stored under room temperature conditions (30 ° C.), and bisphenol A that had passed 1 hour, 2 hours, 8 hours, 24 hours, and 48 hours after granulation was the same as in Example 1. The analysis was performed by high performance liquid chromatography. As a result of the measurement, the IPP concentrations were 202 (after granulation (hereinafter the same) 1 hour), 178 (2 hours), 162 (8 hours), 132 (24 hours), 98 (48 hours) mass ppm, respectively.
The obtained bisphenol A was also evaluated for hue by APHA as in Example 1. All the results were APHA60.
Further, a polycarbonate was produced according to the production example in the same manner as in Example 1 except that bisphenol A obtained in this example was used, and a molded body was prepared in the same manner as in Example 1, and the YI value was measured. The results are shown in Table 2.

Example 1 is the removal of free acid and the amount of washing liquid for washing adduct crystals (including recrystallization), Example 2 is the removal of free acid, Example 3 is adduct crystals (recrystallization) The amount of the cleaning solution for cleaning is increased. On the other hand, the comparative example 1 does not include the free acid removal step, and the amount of the cleaning liquid for cleaning the adduct crystals is lower than that of the example.
From Table 1, the APHA value of Comparative Example 1 in which the isopropenyl phenol concentration under the ambient temperature condition of 30 ° C. for 1 hour after granulation of bisphenol A exceeds 150 ppm by mass is as follows. Compared with Examples 1 to 3 controlled to ppm or less, it is greatly increased, and it can be seen that the hue is greatly deteriorated. In addition, the polycarbonate molded articles produced using bisphenol A having excellent hues in Examples 1 to 3 have excellent YI values. On the other hand, the polycarbonate molded body produced using bisphenol A of Comparative Example 1 inferior in hue has a poor YI value, indicating that the transparency is not improved.
The isopropenylphenol concentration varies with time as summarized in Table 1, but as is apparent from Examples 1 to 3 and Comparative Example 1, the concentration of isopropenylphenol at 150 hours after granulation of bisphenol A was 150 ppm by mass. It turns out that bisphenol A excellent in hue can be manufactured by controlling to the following.

According to the present invention, within 1 hour after granulation of bisphenol A, the isopropenylphenol concentration is monitored under an ambient temperature condition of 10 to 50 ° C., and the hue is good by controlling the concentration to 150 mass ppm or less. Bisphenol A can be produced.

Claims

A method for producing bisphenol A, wherein the concentration of isopropenyl phenol under ambient temperature conditions of 10 to 50 ° C. is monitored within 1 hour after granulation of bisphenol A, and the concentration is controlled to 150 ppm by mass or less.
(1) a condensation reaction step in which an excess amount of phenol and acetone is subjected to a condensation reaction in the presence of an acidic catalyst;
(2) a crystallization / solid-liquid separation step of cooling the reaction mixture obtained in step (1) to crystallize an adduct of bisphenol A and phenol, and separating the adduct and mother liquor;
(3) Adduct decomposition step for removing phenol from the adduct of bisphenol A and phenol obtained in step (2) to obtain a bisphenol A melt, and (4) bisphenol A melt obtained in step (3). Granulating process,
In the method for producing bisphenol A having
A method for producing bisphenol A, wherein the concentration of isopropenyl phenol under ambient temperature conditions of 10 to 50 ° C. is monitored within 1 hour after granulation of bisphenol A, and the concentration is controlled to 150 ppm by mass or less.
(D) The method for producing bisphenol A according to claim 2, further comprising a concentration step of concentrating the reaction mixture obtained in step (1).
The method for producing bisphenol A according to any one of claims 1 to 3, further comprising (A) a free acid removing step, wherein the isopropenylphenol concentration is controlled by removing the free acid.
5. The isopropenyl phenol concentration is controlled by changing a washing liquid amount for washing an adduct crystal of bisphenol A and phenol in the crystallization / solid-liquid separation step (2). The manufacturing method of bisphenol A of description.
The method for producing bisphenol A according to claim 5, wherein the amount of the cleaning liquid is 10 to 100 parts by mass with respect to 100 parts by mass of an adduct crystal of bisphenol A and phenol.
(B) All or part of the mother liquor obtained in the crystallization / solid-liquid separation step (2) is isomerized with an isomerization catalyst, and the isomerization solution is condensed in the condensation reaction step (1) and / or concentrated. An isomerization step to be circulated in step (D); and (C) a recovery step of recovering an adduct of bisphenol A and phenol from the remainder of the isomerization treatment liquid treated in the isomerization step (B). Item 7. A method for producing bisphenol A according to any one of Items 2 to 6.