KR102027847B1 - Bisphenol-a production method - Google Patents

Abstract

The present invention is a step of condensing and reacting excess phenol and acetone in the presence of an acid catalyst, to produce BPA, to obtain a reaction mixture containing BPA (A), and to concentrate the reaction mixture to obtain a concentrate. (B), the step of crystallizing the concentrated liquid after crystallization, separating the solid into a solid and a mother liquid (C), a step of isomerizing at least a part of the mother liquid present in the system in the mother liquid (D), and after isomerization treatment After the solution is crystallized, solid-liquid separation is carried out to separate the solid and the mother liquor, and at least a part of the mother liquor present in the system is subjected to an alkali decomposition treatment in the mother liquor obtained in the previous step to recover phenol and / or IPP. According to the production method of bisphenol A having the step (F) of supplying to the reactor of step (A) without passing through the recombination reactor, the amount of raw materials to be supplied is effectively reduced. In addition, bisphenol A of high quality can be produced.

Description

The manufacturing method of bisphenol A {BISPHENOL-A PRODUCTION METHOD}

The present invention relates to a process for the preparation of bisphenol A (2,2-bis (4-hydroxyphenyl) propane), and more particularly to a process for producing bisphenol A from phenol and acetone.

Bisphenol A is known to be an important compound as a raw material for engineering plastics such as polycarbonate resins, polyarylate resins, or epoxy resins, and in recent years, the demand tends to increase gradually. As a raw material for producing a high quality resin, a high quality bisphenol A is required.

Bisphenol A is usually prepared by stoichiometrically reacting excess phenol and acetone in the presence of an acidic catalyst. And bisphenol A is obtained from a solution after the said reaction as a product (adduct) of bisphenol A and a phenol by crystallization and solid-liquid separation, and is obtained as a product by removing the phenol contained in an adduct. The mother liquor from which the adduct is separated after crystallization is circulated in a reaction step or the like and reused in the system.

Regarding the manufacturing method of such bisphenol A, the method of manufacturing high quality bisphenol A efficiently is proposed.

In Patent Literature 1, a part of the mother liquor obtained by separating and dividing the reaction solution after the reaction of phenol and acetone is returned to the reactor, and a part of the mother liquor is subjected to an isomerization step, a mother liquor concentration step, a crystallization and a solid liquid separation step, and a bisphenol A The manufacturing method which has the process of recovering a bisphenol A and a phenol and returning it to a reactor after obtaining the collection | recovery solution which collect | recovered the addition product of and phenol, through an alkali decomposition process and a recombination reaction process from this collection | recovery solution is disclosed.

In addition, Patent Literature 2 discloses a condensation reaction step after the entire amount of the mother liquor is subjected to isomerization without circulating the mother liquor after the separation of bisphenol A and phenol by crystallization from the reaction mixture after the reaction of phenol and acetone in a reactor. In order to prevent the accumulation of impurities in the system while recycling to a concentration step or a crystallization / solid-liquid separation step, a manufacturing method having a process of recovering bisphenol A and phenol from a blown isomerization liquid is disclosed. .

Japanese Patent Publication No. 2009-242316 Japanese Patent Laid-Open No. 2004-359594

However, in the method which has a process which returns a part of mother liquid of a reaction solution to a reactor as described in patent document 1, there exists a problem that the quality of the bisphenol A obtained is inferior because an impurity is contained in the said mother liquid.

Moreover, although the manufacturing method of patent document 2 can obtain bisphenol A of high quality, after collect | recovering bisphenol A and phenol from an isomerization process liquid, the remaining solution is discarded. The said solution contains the active ingredient which can become p-isopropenyl phenol which is an intermediate of phenol and bisphenol A by alkali decomposition.

In the manufacturing method of bisphenol A, reduction of the amount of the raw material used to supply the effective use of the said discarded solution is desired.

This invention is made | formed in view of the said subject, and an object of this invention is to provide the manufacturing method of bisphenol A which can manufacture high quality bisphenol A, and can reduce the usage-amount of raw material to supply effectively.

MEANS TO SOLVE THE PROBLEM This inventor discovered that the said subject can be solved by going through the specific process, without returning the mother liquid isolate | separated from the reaction liquid mixture after reaction of a phenol and acetone to the reactor in which the said reaction is performed in the manufacturing method of bisphenol A. The invention has been completed.

That is, the present invention provides the following [1] to [7].

[1] A method for producing bisphenol A having the following steps (A) to (F).

Step (A): a step of producing a reaction mixture containing bisphenol A by producing bisphenol A in a reactor for condensing excess phenol and acetone in the presence of an acid catalyst.

Step (B): step of concentrating the reaction mixture obtained in Step (A) to obtain a concentrate

Process (C): The process of isolate | separating solid solution containing bisphenol A and the addition product of a phenol, and a mother liquid by crystallizing the concentrate obtained at process (B), and solidifying

Process (D): The process of isomerizing at least one part of the said mother liquid which exists in a system among the mother liquid obtained at the process (C).

Process (E): The process of solidifying and separating a solution after the isomerization process of process (D), and separating into solid content and a mother liquid

Step (F): Of the mother liquor obtained in the step (E), at least a part of the mother liquor present in the system is subjected to an alkali decomposition treatment to recover phenol and / or p-isopropenylphenol, and the recovered phenol and / or supplying p-isopropenylphenol to the reactor of step (A) without passing through a recombination reactor

[2] The method for producing bisphenol A according to the above [1], wherein in step (D), the entire amount of the mother liquor present in the system is isomerized in the mother liquor obtained in step (C).

[3] In the above [1] or [2], 5 to 30% by mass of the solution after isomerization in step (D) is sent to step (E), and 95 to 70% by mass of the solution is subjected to step (B). The manufacturing method of bisphenol A returned to the.

[4] The bisphenol according to any one of the above [1] to [3], wherein in the step (F), the recovered phenol and / or p-isopropenylphenol is directly supplied to the reactor of the step (A). A manufacturing method.

[5] The process according to any one of [1] to [4], wherein the mother liquor is solid-liquid separated in step (E) to remove phenol, and the mother liquor after the phenol recovery is sent to step (F). Process for the preparation of bisphenol A.

[6] The method for producing bisphenol A according to any one of [1] to [5], wherein the color (APHA) measured by a colorimetric method based on JIS K 4101 of bisphenol A to be produced is 15 or less.

According to the manufacturing method of bisphenol A of this invention, high quality bisphenol A can be manufactured and the usage-amount of the raw material to be supplied can be reduced effectively.

BRIEF DESCRIPTION OF THE DRAWINGS It is process drawing which shows an example of the manufacturing method of bisphenol A of this invention.
2 is a flowchart of a method for producing bisphenol A according to Example 1. FIG.
3 is a flowchart of a method for producing bisphenol A described in Comparative Example 1. FIG.
4 is a flowchart of a method for producing bisphenol A described in Comparative Example 2. FIG.

The manufacturing method of bisphenol A of this invention has the following process (A)-(F).

Step (A): a step of producing a reaction mixture containing bisphenol A by producing bisphenol A in a reactor for condensing excess phenol and acetone in the presence of an acid catalyst.

Step (B): step of concentrating the reaction mixture obtained in Step (A) to obtain a concentrate

Process (C): The process of isolate | separating solid solution containing bisphenol A and the addition product of a phenol, and a mother liquid by crystallizing the concentrate obtained at process (B), and solidifying

Process (D): The process of isomerizing at least one part of the said mother liquid which exists in a system among the mother liquid obtained at the process (C).

Process (E): The process of solidifying and separating a solution after the isomerization process of process (D), and separating into solid content and a mother liquid

Step (F): Of the mother liquor obtained in the step (E), at least a part of the mother liquor present in the system is subjected to an alkali decomposition treatment to recover phenol and / or p-isopropenylphenol, and the recovered phenol and / or supplying p-isopropenylphenol to the reactor of step (A) without passing through a recombination reactor

The manufacturing method of bisphenol A of this invention is a manufacturing method which does not return the mother liquid isolate | separated from the reaction liquid mixture after reaction of a phenol and acetone to the reactor in which the said reaction is performed. Therefore, bisphenol A of high quality can be manufactured because the amount of impurities present in the reactor is reduced.

In the step (D), at least a part of the mother liquor present in the system isomerized in the mother liquor from which the solid content is separated, thereby converting the component capable of isomerization among the impurities in the mother liquor to bisphenol A as much as possible. Can increase the concentration. Therefore, in order to prevent accumulation of impurities in the system, when purging a part of the mother liquid out of the system, more of the bisphenol A can be recovered from the purging mother liquid, thereby improving the recovery rate of the bisphenol A.

In addition, the isomerization process in a process (D) refers to the process of converting the by-product produced by a reaction process into a 4,4 'sieve. As said by-product, isomers, such as a 2,4'-form of bisphenol A, are mentioned.

In the step (F), bisphenol A and 2,4'-bisphenol A present in the mother liquid are subjected to alkali decomposition treatment of at least a part of the mother liquid present in the system in the mother liquid from which the solid content is removed from the solution after the isomerization treatment. Impurities such as and trisphenol can be decomposed to recover p-isopropenylphenol (IPP), which is an intermediate of phenol and / or bisphenol A as a raw material, as an active ingredient.

The recovered phenol and / or IPP is passed through a recombination reactor, whereby phenol and IPP react in the recombination reactor to produce bisphenol A, and when the produced bisphenol A is sent into the reactor of step (A), the reaction is highly reactive. Further reaction with the intermediate, IPP, leads to the formation of by-products, which causes deterioration of the quality of the bisphenol A produced.

Therefore, in the present invention, the recovered phenol and / or IPP is supplied to the reactor of step (A) without passing through the recombination reactor.

In addition, since the recovered phenol and / or IPP can be mixed with the raw material phenol and supplied to the reactor of the step (A), the supply amount of the raw material phenol and acetone can be reduced and the high-quality bisphenol A unchanged from the conventional one. Can be obtained.

Hereinafter, the manufacturing method of the bisphenol A of this invention is demonstrated along the process chart which shows an example of the manufacturing method of the bisphenol A of this invention shown in FIG.

[Step (A)]

Step (A) is a step of producing bisphenol A to obtain a reaction mixture containing bisphenol A in a reactor in which an excess of phenol and acetone are condensed in the presence of an acid catalyst.

In this step, the supplied phenol and acetone are condensed to produce p-isopropenylphenol (IPP), and then the IPP and phenol are further condensed to produce bisphenol A.

Strongly acidic cation exchange resins are used as the acid catalyst used in the step (A), but sulfonic acid type cation exchange resins are preferred from the viewpoint of catalytic activity.

The sulfonic acid type cation exchange resin is not particularly limited as long as it is a strong acid cation exchange resin having a sulfonic acid group. Sulfonic acid resins and the like. These can also be used individually or in combination of 2 or more types.

Among the above-mentioned strongly acidic cation exchange resins, strong acid cation exchange resins in which a part of the resin is neutralized by mercaptans are preferable.

In the present invention, mercaptans refer to a compound having an SH group in a free form in the molecule. As such mercaptans, the alkyl mercaptans etc. which have 1 or more types of substituents, such as an alkyl mercaptan, a carboxyl group, an amino group, and a hydroxyl group, are mentioned, for example. Among them, 2-mercaptoethylamine, 3-mercaptopropylamine, N, N-dimethyl-3-mercaptopropylamine, N, N-di-n-butyl-4-mercaptobutylamine, 2,2 Mercaptoalkylamines, such as -dimethylthiazolidine, are preferable.

As content of the sulfonic acid group in the strongly acidic cation exchange resin neutralized with mercaptans, Preferably it is 5-35 mol%, More preferably, it is 10-30 mol% with respect to the total amount of all the sulfonic acid groups in the strongly acidic cation exchange resin before neutralization. More preferably, it is 15-25 mol%.

The supply ratio of phenol and acetone is not particularly limited as long as it is a rate at which the phenol is excessively stoichiometrically.

However, from the viewpoint of the ease of purification and economical efficiency of the resulting bisphenol A, the amount of phenol supplied to 1 mol of acetone is preferably 3 to 30 mol, more preferably 5 to 20 mol.

In addition, in manufacture of bisphenol A in this process, addition of a reaction solvent is not specifically needed except in the case where the viscosity of a reaction liquid is too high or when it reacts at low temperature which may become coagulated and difficult to operate.

The condensation reaction of phenol and acetone in this step may be either batch or continuous, but a fixed bed continuous reaction method in which raw materials are continuously supplied and reacted is preferable, and a fixed bed distribution method, which is an extrusion flow method, is more preferred. desirable.

The reaction tower in the fixed bed continuous reaction system may be one, or may be a fixed bed multistage continuous reaction system in which two or more units are arranged in series.

For a fixed bed flow system, the liquid space velocity of the raw material to be supplied to the reactor is preferably from 0.1 to 20hr ^-1, and more preferably from 0.3 to 15hr ^-1, more preferably from 0.5 to 10hr ^-1, more preferably 0.7 to 6 ^{hr −1} .

Moreover, the temperature at the time of reaction of a phenol and acetone becomes like this. Preferably it is 50-100 degreeC, More preferably, it is 55-90 degreeC, More preferably, it is 60-80 degreeC. When reaction temperature is 50 degreeC or more, reaction speed can fully be raised, the viscosity of a reaction liquid mixture can be made into the appropriate range, and the reaction liquid can be prevented from solidifying. On the other hand, when reaction temperature is 100 degrees C or less, reaction control is possible and the selectivity of bisphenol A can be made favorable. In addition, decomposition or deterioration of the catalyst can be prevented.

Moreover, the pressure at the time of reaction of a phenol and acetone becomes like this. Preferably it is normal pressure (0.1 MPa)-1.5 MPa, More preferably, it is normal pressure (0.1 MPa)-0.6 MPa.

[Step (B)]

Step (B) is a step of concentrating the reaction mixture obtained in step (A) to obtain a concentrated solution. By this process, low boiling point substances, such as unreacted acetone, unreacted phenol, and by-product water, etc. are removed from the reaction liquid mixture, and the concentration of the produced bisphenol can be adjusted to an appropriate range.

In this step, the reaction mixture is preferably concentrated by distillation under reduced pressure using a distillation column.

In addition, the concentration of this process is divided into a first concentration step of distilling mainly unreacted acetone, water, low boiling point substances, etc., and a second concentration step of distilling mainly unreacted phenol and the like and adjusting the concentration of the concentrate. It is preferable to carry out.

As conditions for the vacuum distillation in a 1st concentration process, as temperature, Preferably it is 10-200 degreeC, More preferably, it is 20-190 degreeC, More preferably, it is 30-180 degreeC, As a pressure, Preferably it is 10-90 kPa, More preferably, it is 20-80 kPa, More preferably, it is 25-70 kPa.

As conditions of the vacuum distillation in a 2nd concentration process, as temperature, Preferably it is 70-170 degreeC, More preferably, it is 80-140 degreeC, More preferably, it is 85-130 degreeC, As a pressure, Preferably it is 4-70 kPa, More preferably, it is 7-50 kPa, More preferably, it is 10-30 kPa.

In addition, it is preferable to set the temperature and pressure in the vacuum distillation in a 2nd concentration process lower than a 1st concentration process in consideration of the boiling point rise of a component.

The concentration of bisphenol A in the concentrate obtained through the present step is preferably 20 to 60 mass%, more preferably 20 to 40 mass%. If the said density | concentration is 20 mass% or more, the recovery by the crystallization of bisphenol A can be performed efficiently. On the other hand, if it is 60 mass% or less, solidification temperature does not become high and it can prevent the troubles, such as difficulty of conveying the slurry after crystallization.

[Step (C)]

Process (C) is a process of solid-liquid separation after crystallizing the concentrate obtained in process (B), and separating into solid content containing bisphenol A and the adduct of phenol (henceforth "adduct"), and a mother liquid. .

As a crystallization method of solid content from the solution after concentration, it is preferable to cool the concentrated liquid immediately after completion | finish of vacuum distillation before crystallization to 35-60 degreeC (preferably 40-55 degreeC), and to crystallize the said solid content and to make a slurry.

The cooling at this time may be performed using an external heat exchanger, or may be performed by a vacuum cooling crystallization method in which water is added to the concentrate and cooled using latent heat of evaporation of water under reduced pressure.

Subsequently, the slurry containing the solid content thus crystallized is separated into a mother liquor containing the solid and the reaction by-product by known means such as filtration or centrifugation. Although there is no restriction | limiting in particular as an apparatus used at this time, For example, a belt filter, a drum filter, a tray filter, a centrifugal separator, etc. are mentioned.

In addition, the solid content after solid-liquid separation after crystallization may be redissolved, and solid-liquid separation may be repeated after crystallization again. By repeating crystallization and solid-liquid separation in multiple stages, impurities introduced into the crystal can be reduced. As a dissolution liquid of re-dissolution, a phenol, water, a water-phenol mixed liquid, etc. are mentioned, for example. As the phenol, phenol recovered from the system may be used, or phenol supplied separately from the system may be used.

In addition, the separated solid content is washed, sent to the adduct decomposition step, and phenol is removed from the adduct contained in the solid content, thereby obtaining high-purity bisphenol A.

As a washing | cleaning liquid used at this time, a phenol, water, a water-phenol mixture liquid, etc. are mentioned, for example. As the phenol, phenol recovered from the system may be used, or phenol supplied separately from the system may be used.

The amount of the cleaning liquid to be used is preferably 0.1 to 10 times the mass of the separated solids in terms of the cleaning efficiency and the loss for re-dissolution, the circulation, recovery and reuse of the cleaning liquid.

[Adduct decomposition process]

The adduct (adduct) of bisphenol A and phenol contained in the solid content recovered by the above-mentioned solid-liquid separation is decomposed into bisphenol A and phenol through an adduct decomposition step, and high purity bisphenol A is obtained by removing phenol. Can be.

In the adduct decomposition step, it is preferable to first go through the step of dissolving the adduct into bisphenol A and phenol by heating and melting the solid content containing the adduct at preferably 100 to 160 ° C, and obtaining a melt containing them.

Subsequently, this melt is sent to an evaporation tower, phenol is removed from the melt by distillation under reduced pressure or the like, and bisphenol A in a molten state is recovered. It is preferable to perform the said vacuum distillation under the conditions of the pressure of 1-11 kPa at the temperature of 150-190 degreeC.

In addition, it is preferable that the recovered bisphenol A further removes the remaining phenol by steam stripping.

Through this process, bisphenol A of high purity can be obtained.

[Step (D)]

Process (D) is a process of isomerizing at least one part of the said mother liquid which exists in a system with the mother liquid obtained at process (C).

The composition of the mother liquid obtained in the step (C) is usually 5 to 15% by mass of impurities such as phenol: 65 to 85% by mass, bisphenol A: 10 to 20% by mass, 2,4'-isomer, and impurities such as isomers. This includes a lot.

In the present invention, in the mother liquor obtained in the step (C), a part of the mother liquor may be discharged out of the system, but at least a part of the mother liquor present in the system is at least subjected to isomerization treatment after the discharge.

As described above, by isomerizing at least a part of the mother liquid present in the system, the impurities in the mother liquid can be converted to bisphenol A as much as possible to increase the concentration of bisphenol A. Therefore, when purging a part of mother liquid out of a system in order to prevent accumulation of an impurity in a system, more bisphenol A can be collect | recovered from a purge mother liquid, and the recovery rate of bisphenol A can be improved.

From the viewpoint of improving the recovery rate of bisphenol A, the ratio of the mother liquor which isomerized in the mother liquor present in the system in the present step is preferably 50 to 100% by mass, more preferably 70 to 100% by mass, still more preferably It is especially preferable that it is 80-100 mass%, More preferably, it is 90-100 mass%, and isomerizing the whole quantity of the said mother liquid which exists in a system.

Moreover, it is preferable to perform isomerization of the whole quantity of the mother liquid obtained at the process (C) from a viewpoint of improving the recovery rate of bisphenol A.

As the catalyst used in the isomerization treatment, sulfonic acid type cation exchange resins are preferable. As sulfonic acid type cation exchange resin, resin used at the above-mentioned process (A) is mentioned.

It is preferable that the isomerization treatment is carried out in a fixed bed flow system that is continuously extruded at a reaction temperature of 50 to 100 ° C. (preferably 60 to 90 ° C.) in the presence of the sulfonic acid type cation exchange resin.

In the case of the fixed bed flow system, the liquid space velocity of the solution is preferably from 0.1 to 20hr ^-1, more preferably from 0.3 to 15hr ^-1, more preferably from 0.5 to 10hr ^-1.

In addition, the reactor which performs isomerization process in this process may be provided in plurality in parallel. For example, the mother liquor obtained in the step (C) is divided into an isomerization reactor for recycling to the step (B) after the isomerization treatment, and an isomerization reactor for sending the solution after the isomerization treatment to the step (E). It is also possible to install.

Although the solution after isomerization process is sent to process (E), it is preferable to return a part of this solution to process (B). By returning a part of the solution after isomerization to process (B), the bisphenol A produced | generated by the isomerization process can be collect | recovered, and the recovery rate of bisphenol A can be improved. In addition, since the solution after isomerization contains 65-85 mass% of phenols, it is preferable to return this solution to process (B) also in order to evaporate a part and produce it in the density | concentration of bisphenol A corresponding to crystallization operation. .

In view of the above, the solution amount sent to the step (E) in the solution after the isomerization treatment is preferably 5 to 30% by mass, more preferably 10 to 25% by mass, still more preferably 13 to 23% by mass, and the step As solution amount returned to (B), Preferably it is 95-70 mass%, More preferably, it is 90-75 mass%, More preferably, it is 87-77 mass%.

[Step (E)]

Process (E) is a process of solid-liquid separation after crystallizing the solution after the isomerization process of process (D), and separating into solid content and a mother liquid. By this process, solid content containing bisphenol A and the adduct (adduct) of a phenol is crystallized, and it isolate | separates into solid content and a mother liquid.

It is preferable that the solution after isomerization process removes and concentrates a part of phenol before crystallization. The concentration is carried out under conditions of a temperature of 70 to 140 ° C. (preferably 80 to 125 ° C., more preferably 90 to 115 ° C.) and a pressure of 1.5 to 40 kPa (preferably 2.0 to 25 kPa, more preferably 3.0 to 15 kPa). It is preferable to carry out by vacuum distillation. As a density | concentration of bisphenol A of the solution after concentration, Preferably it is 20-50 mass%.

As a crystallization method of solid content from the solution after concentration, it is preferable to cool the solution immediately after completion | finish of distillation under reduced pressure to 35-60 degreeC (preferably 40-55 degreeC), and to crystallize the said solid content and to make a slurry. Cooling at this time can be performed by the method similar to process (C) mentioned above.

In addition, the slurry containing solid content can be isolate | separated into crystallized solid content and a mother liquid by the method similar to the process (C) mentioned above.

It is preferable to return the solid content (henceforth "recovery crystal | crystallization") crystallized here to a process (B) or a process (C) mentioned above. Although the said recovery crystal | crystallization contains more impurity than the crystal | crystallization obtained at the process (C) mentioned above, the density | concentration of an impurity in a recovery crystal | crystallization is lower than the density | concentration of the impurity in the reaction liquid mixture obtained at a process (A). Therefore, by returning a recovery crystal to a process (B) or a process (C), the density | concentration of the impurity in the reaction liquid mixture obtained at the process (A) becomes low, and a crystal of higher purity can be obtained than when a recovery crystal is not supplied.

Moreover, in this invention, it is preferable to perform a phenol recovery process with respect to the mother liquid which solid-liquid-separated and removed solid content in process (E), and sends the mother liquid after a phenol recovery process to process (F).

The composition of the mother liquor obtained in the step (E) is usually 45 to 70% by mass, bisphenol A: 5 to 15% by mass, and 20 to 40% by mass of impurities such as 2,4'-isomer. The mother liquor contains many impurities such as 2,4'-isomers, but in many cases, more phenol is contained than these impurities. Therefore, in view of the efficiency of phenol recovery, in order to recover many phenols contained in the mother liquor before the mother liquor is sent to step (F), a phenol recovery treatment is performed on the mother liquor which has been subjected to solid-liquid separation in step (E). It is preferable to carry out.

As a method for recovering phenol in the phenol recovery process, a method of recovering phenol from the column top by distillation under reduced pressure using a packed distillation column or the like, and obtaining a residual liquid containing a large amount of by-products and coloring substances after phenol recovery from the bottom desirable.

As conditions for the said vacuum distillation, it is preferable to carry out on condition of the temperature of 120-180 degreeC (preferably 135-170 degreeC), and the pressure of 0.5-20 kPa (preferably 1.0-10 kPa). Moreover, it is preferable to perform this vacuum distillation until the amount of residual phenols in a residual liquid becomes 20 mass% or less, More preferably, it becomes 2-15 mass%.

The phenol recovered here can be used, for example, as a washing liquid or re-dissolving solution for solids in the crystallization and solid-liquid separation step of step (C) or (E), or as a raw material for reaction used in step (A). .

[Step (F)]

Step (F) is an alkali decomposition treatment of at least a part of the mother liquor present in the system in the mother liquor obtained in step (E) to recover and recover phenol and / or p-isopropenylphenol (IPP). It is a process of supplying phenol and / or IPP to the said reactor of process (A) without passing through a recombination reactor.

Moreover, in this process, alkali decomposition process can also be performed with respect to the whole quantity of the said mother liquid which exists in a system among the mother liquid obtained at the process (E). However, it is preferable to perform a phenol recovery process to the mother liquid from which solid-liquid separation and solid content were removed in the process (E), and alkali decomposition treatment is performed with respect to the remaining mother liquid after collect | recovering phenol.

As mentioned above, the mother liquid which solid-separated and removed the solid substance in process (E) contains many impurities, such as bisphenol A and a 2,4'-isomer. Moreover, about the mother liquid after collect | recovering phenol from the said mother liquid, the ratio of impurities, such as this bisphenol A and a 2,4'-isomer, increases. In this process, alkali is added to these mother liquids containing many impurities, and this mother liquid is supplied to the reaction tank of an alkali decomposition reaction tower. By operating under high temperature and reduced pressure, impurities such as bisphenol A and 2,4'-isomers are decomposed into phenol and IPP.

The said phenol and IPP can be collect | recovered from the tower top of a reaction tower, and impurities, such as a chroman compound, are converted into a heavy impurity (high boiling point), and are taken out as tar (residue) from the tower bottom (reactor) of a reaction tower.

In addition, both the said phenol and IPP may be collect | recovered, and only one may be collect | recovered.

In addition, an alkali decomposition process can be performed in either a continuous type or a batch type.

In the present invention, a part of the mother liquor obtained in step (E) may be discharged out of the system, but at least a part of the mother liquor present in the system at least after the discharge is subjected to alkali decomposition treatment.

As described above, at least a part of the mother liquor present in the system is subjected to alkali decomposition to decompose bisphenol A, 2,4'-bisphenol A, trisphenol and the like present in the mother liquor to recover phenol and / or IPP. can do. Since IPP is a product from phenol and acetone, and is an intermediate of bisphenol A, by reducing the phenol and / or IPP obtained in step (A), the supply amount of phenol and acetone, which are raw materials that need to be newly supplied into the system, is reduced. You can.

In addition, from the viewpoint of improving the recovery rate of phenol and / or IPP and reducing the supply amount of phenol and acetone that need to be newly supplied into the system, it is preferable to carry out alkali decomposition treatment of the entire amount of the mother liquor obtained in step (E).

Examples of the alkali used in the alkali decomposition treatment include sodium hydroxide and potassium hydroxide, and these may be added in the form of an aqueous solution.

The amount of alkali to be added is preferably 0.01 to 3.0% by mass, and more preferably 0.05 to 2.0% by mass with respect to the supply amount except for phenol supplied to the reaction tank.

When performing an alkali decomposition process, the temperature of a reaction tank and a distillation column becomes like this. Preferably it is 180-350 degreeC, More preferably, it is 190-300 degreeC, More preferably, it is 200-280 degreeC.

In addition, the pressure of the reaction tank and the distillation column is preferably 0.5 to 50 kPa, more preferably 1.5 to 20 kPa, still more preferably 3.0 to 10 kPa.

In the present invention, the phenol and / or IPP recovered from the column top is condensed and mixed with phenol and acetone as feedstocks, and then supplied to the reactor of step (A). In addition, the phenol recovered in this step and / or IPP can be condensed and liquefied together with the phenol recovered up to the previous step.

Here, when the recovered phenol and / or IPP is supplied to the reactor of step (A) via the recombination reactor, as described above, phenol and IPP react in the recombination reactor to produce bisphenol A. When the produced bisphenol A is sent into the reactor of the step (A), by-products are further reacted with IPP, which is a highly reactive reaction intermediate, to cause deterioration of the quality of the produced bisphenol A.

Therefore, in the present invention, the recovered phenol and / or IPP is supplied to the reactor of step (A) without passing through the recombination reactor.

Further, the recovered phenol and IPP may be supplied to the reactor of step (A) via another step or reactor within a range that does not impair the effects of the present invention unless it passes through the recombination reactor, It is preferred to be fed to the reactor.

As described above, according to the production method of the present invention, bisphenol A of colorless and high purity can be produced while effectively reducing the amount of raw materials to be supplied.

The color (APHA) measured by the colorimetric method based on JIS K 4101 of bisphenol A obtained by the manufacturing method of the present invention is preferably 15 or less, more preferably 12 or less, and still more preferably 10 or less.

EXAMPLE

EXAMPLES The present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples at all.

In the following examples and comparative examples, phenol, bisphenol A, and the like produced during the production process were quantified by HPLC analysis.

In addition, the color (APHA) of the produced bisphenol A was dissolved in 20 g of bisphenol A in 20 ml of ethanol, and was subjected to JIS K using a spectrophotometer (manufactured by Hitachi Seisakusho Co., Ltd., product name "U-3410 type magnetic spectrophotometer"). It measured by the colorimetric method based on 4101.

Example 1

2 is a flowchart of a method for producing bisphenol A according to the first embodiment. Hereinafter, according to the process diagram shown in FIG. 2, the method of manufacturing bisphenol A performed in Example 1 is demonstrated.

As a catalyst, a fixed-bed reactor packed with 20 mol% of sulfonic acid groups partially neutralized with 2-mercaptoethylamine to sulfonic acid type cation exchange resin (manufactured by Mitsubishi Chemical Corporation, product name "Dia ion-104H"). The mixture of 51.9 t / h of phenol 51.9 t / h and 4.5 t / h of acetone was continuously supplied at 1.0hr ^-1 of liquid space velocity in the environment of normal pressure (0.1 Mpa), maintaining the temperature of a catalyst layer at 80 degreeC (acetone The amount of phenol supplied per mole is 7.1 moles). And bisphenol A was produced | generated and the reaction liquid mixture containing this bisphenol A was obtained (process (A)).

From the obtained reaction liquid mixture, unreacted acetone, reaction product water, and a low boiling point substance are distilled mainly under the conditions of the temperature of 150 degreeC, and pressure of 40 kPa, and then phenol is distilled off mainly under the conditions of temperature of 90 degreeC and pressure of 10 kPa, and concentrated. The obtained liquid was obtained (process (B)).

The concentrated solution was cooled from 90 ° C to 45 ° C, crystallized a solid containing bisphenol A and an adduct (adduct) of phenol, and then separated by a centrifugal separator, into a solid and a mother liquid of 11.2 t / h. It separated (process (C)). Moreover, about solid substance, it wash | cleaned, melt | dissolved, and adduct decomposition, and sent to the distillation column operated under the conditions of the temperature of 170 degreeC, and the pressure of 2 kPa, and phenol was distilled off and collect | recovered. Then, a solution containing bisphenol A was extracted from the bottom of the distillation column, and residual phenol was completely removed from the solution by steam stripping to obtain 6.3 t / h bisphenol A.

On the other hand, the entire amount of the mother liquor of 11.2t / h separated by the centrifugal separator was subjected to sulfonic acid type cation exchange resin (manufactured by Mitsubishi Chemical Corporation, product name "Dia ion-104H") under conditions of a temperature of 70 ° C and a liquid space velocity of ¹ hr ^-1 . ), And an isomerization treatment was performed (step (D)).

Then, the solution of 8.8t / h in the solution after isomerization is returned to the concentration step of step (B), and the remaining 2.4t / h solution is concentrated under the condition of temperature 100 ° C and pressure 5 kPa to distill off some phenols, After cooling to 50 ° C., solids containing bisphenol A and adducts of adducts (adducts) were crystallized and separated by centrifugation. The solids were washed to obtain 0.7t / h solids and 1.7t / h mother liquor. (Step (E)). After this solid melted, it returned to the concentration process of process (B).

On the other hand, the mother liquor from which solid content was removed by said process (E) evaporates a phenol on condition of the temperature of 160 degreeC, and a pressure of 2 kPa, collect | recovers 1.3 t / h phenol, and 0.4t / h the residual liquid (residual Mother liquor).

After adding 10 kg / h of 25% sodium hydroxide aqueous solution, this 0.4t / h residual liquid (residual mother liquid) is supplied to the reaction tank of the alkali decomposition reaction tower which has a reaction tank at the bottom, and the temperature is 250 degreeC, and the pressure is 6.7 kPa. It operated under the conditions of, and obtained 0.21 t / h phenol and p-isopropenyl phenol (IPP) from the tower top of the reaction tower, and obtained 0.17 t / h tar (residue) from the tower bottom (reactor) of the reaction tower. Then, phenol and IPP obtained from the column top were mixed with phenol recovered in another step, and fed directly to the fixed bed reactor of step (A) (step (F)).

The cycle including the above steps was repeated, and the supply phenol and acetone were adjusted so that the yield of bisphenol A was constant at 6.3 t / h. After a certain time, the supply phenol amount was 5.40 t / h, and the supply acetone The amount was 1.70 t / h. In addition, the bisphenol A had a color (APHA) of 10.

Comparative Example 1

3 is a flowchart of a method of producing bisphenol A of Comparative Example 1. FIG. Bisphenol A was prepared according to the process shown in FIG. 3.

That is, except for discarding 0.4t / h residual liquid (residual mother liquid) which remained after recovering phenol from the mother liquid from which solid content was removed in the process (E) of Example 1, without passing through the said process (F), It adjusted so that 6.3 t / h bisphenol A might be manufactured by the manufacturing method similar to 1.

After a certain time, the amount of phenol supplied was 5.55 t / h, and the amount of acetone supplied was 1.75 t / h. In addition, the bisphenol A had a color (APHA) of 10.

The produced bisphenol A was of the same high quality as in Example 1, but in the production method of Comparative Example 1, the amount of supply phenol was 0.15 t / h, the amount of acetone was 0.05 t / h, and it was necessary to supply more than the production method of Example 1. There was.

That is, compared with Example 1, the manufacturing method of the comparative example 1 requires as many raw materials as 1,200 t of supply phenols and 400 tons of acetone.

Comparative Example 2

4 is a flowchart of a method of producing bisphenol A of Comparative Example 2. FIG. Bisphenol A was prepared according to the process diagram shown in FIG. 4.

That is, in the step (F) of Example 1, phenol and IPP obtained from the top of the evaporation tower are mixed with phenol recovered in another process, and bisphenol A is produced by reacting phenol and IPP in a recombination reactor to produce bisphenol A. Except that the reactant containing bisphenol A produced | generated at was supplied to the fixed bed reactor of process (A), it adjusted so that 6.3 t / h bisphenol A may be manufactured by the manufacturing method similar to Example 1.

After a certain time, the amount of supplied phenol was 5.40 t / h, and the amount of acetone supplied was 1.70 t / h, which was the same as in Example 1. However, the color (APHA) of the prepared bisphenol A was 20, which was a result of deterioration in quality compared to the bisphenol A prepared in Example 1. This is considered to be caused by supply of bisphenol A produced in the recombination reactor to the reactor, for example, by-products obtained by further reaction between IPP and bisphenol A present in the reactor remain.

According to the manufacturing method of bisphenol A of this invention, high quality bisphenol A can be manufactured and the usage-amount of the raw material to be supplied can be reduced effectively. Obtained bisphenol A can be used as a raw material of engineering plastics, such as a polycarbonate resin and a polyarylate resin.

Claims (6)

The manufacturing method of bisphenol A which has the following process (A)-(F).
Step (A): a step of producing a reaction mixture containing bisphenol A by producing bisphenol A in a reactor for condensing excess phenol and acetone in the presence of an acid catalyst.
Step (B): step of concentrating the reaction mixture obtained in Step (A) to obtain a concentrate
Process (C): The process of isolate | separating solid solution containing bisphenol A and the addition product of a phenol, and a mother liquid after crystallizing the concentrate obtained in process (B), and solid-liquid separation.
Process (D): The process of isomerizing at least one part of the said mother liquid which exists in a system among the mother liquid obtained at the process (C).
Process (E): The process of solidifying and separating a solution after the isomerization process of process (D), and separating into solid content and a mother liquid
Step (F): Of the mother liquor obtained in the step (E), at least a part of the mother liquor present in the system is subjected to an alkali decomposition treatment to recover phenol and / or p-isopropenylphenol, and the recovered phenol and / or supplying p-isopropenylphenol to the reactor of step (A) without passing through a recombination reactor The process for producing bisphenol A according to claim 1, wherein in step (D), the entire amount of the mother liquid present in the system is isomerized in the mother liquid obtained in step (C). The process of Claim 1 or 2 which sends 5-30 mass% of the solution after the isomerization process of process (D) to a process (E), and returns 95-70 mass% of the said solution to a process (B), Process for the preparation of bisphenol A. The process for producing bisphenol A according to claim 1 or 2, wherein in the step (F), the recovered phenol and / or p-isopropenylphenol is directly supplied to the reactor of the step (A). The manufacturing method of bisphenol A of Claim 1 or 2 which performs a phenol recovery process with respect to the mother liquid which solid-liquid-separated and removed solid content in process (E), and sends the mother liquid after a phenol recovery process to process (F). The manufacturing method of bisphenol A of Claim 1 or 2 whose color (APHA) measured by the colorimetric method based on JISK4101 of bisphenol A manufactured is 15 or less.

Images