KR20150032842A

KR20150032842A - Bisphenol-a production method

Info

Publication number: KR20150032842A
Application number: KR20147036054A
Authority: KR
Inventors: 마사오 사이토; 아유미 도요노; 다카시 나카가와; 다카시 하야카와; 마사히로 고다마
Original assignee: 이데미쓰 고산 가부시키가이샤
Priority date: 2012-06-28
Filing date: 2013-06-13
Publication date: 2015-03-30
Also published as: CN104379546A; WO2014002787A1; KR102027847B1; TWI593667B; CN104379546B; RU2014152829A; RU2627266C2; TW201418204A; JPWO2014002787A1; JP6055472B2

Abstract

The present invention relates to a process for producing a BPA-containing reaction mixture, comprising the steps of: (A) producing a BPA in a reactor for condensing excess phenol and acetone in the presence of an acid catalyst to obtain a reaction mixture containing BPA; (B), a step (C) of crystallizing the concentrate, followed by solid-liquid separation and separation into a solid fraction and a mother liquor, a step (D) of isomerizing at least a part of the mother liquor present in the system, (E) separating the solid solution and solid solution from the mother liquor obtained by the preliminary step, separating the solid solution and solid solution from the solution, crystallizing at least a part of the mother liquor present in the system, and recovering phenol and / or IPP And the step (F) of feeding the reactant of the step (A) to the reactor without passing through the re-combination reactor, it is possible to effectively reduce the amount of the raw material to be supplied High-quality bisphenol A can be produced.

Description

BISPHENOL-A PRODUCTION METHOD [0002]

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

It is known that bisphenol A is an important compound as a raw material for engineering plastics such as polycarbonate resin and polyarylate resin, epoxy resin, etc. In recent years, its demand tends to increase. High-quality bisphenol A is required as a raw material for producing a high-quality resin.

Bisphenol A is usually prepared stoichiometrically by reacting excess phenol and acetone in the presence of an acidic catalyst. Then, bisphenol A is recovered from the solution after the reaction as an adduct (adduct) of bisphenol A and phenol by crystallization and solid-liquid separation to remove phenol contained in the adduct. After the crystallization, the mother liquor from which the adduct is separated is circulated through the reaction process and reused in the system.

With regard to the process for producing such bisphenol A, a process for efficiently producing high-quality bisphenol A has been proposed.

In Patent Document 1, a portion of the mother liquor obtained by separating and separating 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 isomerization step, mother liquid concentration step, crystallization and solid- And a step of recovering bisphenol A and phenol from the recovered solution through an alkali decomposition step and a recombination reaction step and returning the recovered bisphenol A and phenol to the reactor.

In addition, Patent Document 2 discloses a method in which the entire mother liquor is isomerized without circulating the mother liquor after crystallization of adducts of bisphenol A and phenol to the reactor from the reaction mixture after the reaction of phenol and acetone, , A process for recycling bisphenol A and phenol from an isomerization liquid to be blown to prevent accumulation of impurities in the system while recirculating it to a concentration step or a crystallization / solid-liquid separation step .

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

However, in the method having a process of returning a part of the mother liquor of the reaction liquid to the reactor as described in Patent Document 1, there is a problem that the quality of bisphenol A obtained is deteriorated because impurities are contained in the mother liquor.

Further, in the production method described in Patent Document 2, bisphenol A of high quality can be obtained, but bisphenol A and phenol are recovered from the isomerization treatment solution, and then the remaining solution is discarded. This solution contains an active ingredient which can be phenol or an intermediate of bisphenol A, p-isopropenylphenol, by alkali decomposition.

In the method for producing bisphenol A, it has been desired to reduce the amount of the raw material to be supplied by effectively using the solution that has been discarded in the past.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a process for producing bisphenol A which can produce high-quality bisphenol A and can effectively reduce the amount of raw materials to be supplied.

The inventors of the present invention have found that the above problems can be solved by carrying out a specific process without returning the mother liquor separated from the reaction mixture after the reaction of phenol and acetone to the reactor in which the reaction is carried out in the process for producing bisphenol A Thereby completing the invention.

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

[1] A process for producing bisphenol A, which comprises the following steps (A) to (F).

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

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

Step (C): The concentrate obtained in the step (B) is crystallized and solid-liquid separated, and a solid component containing an adduct of bisphenol A and phenol and a step

Step (D): a step of isomerizing at least a part of the mother liquor present in the system in the mother liquor obtained in the step (C)

Step (E): a step of crystallizing a solution after the isomerization of the step (D), followed by solid-liquid separation, and separating the solid and the mother liquid

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

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

[3] The method according to the above [1] or [2], wherein 5 to 30 mass% of the solution after the isomerization of the step (D) is sent to the step (E), 95 to 70 mass% To yield a bisphenol A compound.

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

[5] The method according to any one of [1] to [4], wherein phenol recovery is carried out for the mother liquor from which the solid content has been removed by solid-liquid separation in the step (E), the mother liquor after the phenol recovery treatment is sent to the step (F) Process for the production of bisphenol A.

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

According to the process for producing bisphenol A of the present invention, high-quality bisphenol A can be produced, and the amount of raw material to be supplied can be effectively reduced.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a process diagram showing an example of a process for producing bisphenol A of the present invention. FIG.
Fig. 2 is a flow chart of a process for producing bisphenol A described in Example 1. Fig.
3 is a process diagram of a process for producing bisphenol A described in Comparative Example 1. Fig.
4 is a flow chart of a process for producing bisphenol A described in Comparative Example 2. Fig.

The process for producing bisphenol A of the present invention has the following steps (A) to (F).

The production method of bisphenol A of the present invention is a production method in which the mother liquor separated from the reaction mixture after the reaction of phenol and acetone is not returned to the reactor in which the reaction is carried out. As a result, the amount of impurities present in the reactor is reduced, so that high-quality bisphenol A can be produced.

In the step (D), at least a part of the mother liquor present in the system among the mother liquors from which the solid component is separated is subjected to isomerization treatment to convert the isomerizable component of the mother liquor into the bisphenol A, Can be increased. Therefore, when pumping a part of the mother liquor out of the system to prevent impurities from accumulating in the system, more bisphenol A can be recovered from the purifying mother liquor and the recovery rate of bisphenol A can be improved.

The isomerization treatment in the step (D) refers to a treatment in which a by-product produced in the reaction step is converted into a 4,4'-sieve. As the by-product, an isomer such as a 2,4'-isomer of bisphenol A can be mentioned.

Further, in the step (F), at least a part of the mother liquid present in the system is subjected to alkali decomposition treatment in the mother liquid from which the solid content has been removed from the solution after the isomerization treatment to obtain bisphenol A, 2,4'-bisphenol A , Trisphenol and the like can be decomposed to recover p-isopropenylphenol (IPP), which is an intermediate of phenol and / or bisphenol A as a raw material, as an effective component.

When the recovered phenol and / or IPP is passed through a re-combination reactor, phenol and IPP react with each other in the re-combination reactor to produce bisphenol A, and when the produced bisphenol A is sent to the reactor of process (A) And further reacts with the intermediate IPP to form a by-product, which is a cause of deterioration of the produced bisphenol A.

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

Further, since the recovered phenol and / or IPP can be mixed with the raw phenol and supplied to the reactor of the step (A), the amount of phenol or acetone as a raw material can be reduced, and high-quality bisphenol A Can be obtained.

Hereinafter, the process for producing bisphenol A of the present invention will be described with reference to a process diagram showing an example of the process for producing bisphenol A of the present invention shown in Fig.

[Step (A)]

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

In the present step, the supplied phenol and acetone undergo a condensation reaction to produce p-isopropenylphenol (IPP), and then the IPP and phenol are further condensed to produce bisphenol A.

As the acid catalyst used in the step (A), a strongly acidic cation exchange resin is used, and in view of catalytic activity, a sulfonic acid type cation exchange resin is preferable.

The sulfonic acid type cation exchange resin is not particularly limited as long as it is a strongly acidic cation exchange resin having a sulfonic acid group, and examples thereof include sulfonic acid styrene-divinylbenzene copolymer, sulfonated bridged styrene polymer, phenol formaldehyde-sulfonic acid resin, benzene formaldehyde- Sulfonic acid resin and the like. These may be used alone or in combination of two or more.

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

In the present invention, the term "mercaptans" means a compound having in its molecule a SH group in a liberated form. Examples of such mercaptans include alkyl mercaptans having at least one substituent such as an alkyl mercaptan, a carboxyl group, an amino group, and a hydroxyl group. Among them, 2-mercaptoethylamine, 3-mercaptopropylamine, N, N-dimethyl-3-mercaptopropylamine, N, Mercaptoalkylamines such as dimethylthiazolidine are preferable.

The content of the sulfonic acid group in the strongly acidic cation exchange resin neutralized by mercaptans is preferably 5 to 35 mol%, more preferably 10 to 30 mol%, more preferably 10 to 30 mol%, relative to the total amount of the sulfonic acid groups in the strongly acidic cation- , And more preferably 15 to 25 mol%.

The supply ratio of phenol and acetone is not particularly limited as long as it is a stoichiometric excess of phenol.

However, the amount of phenol supplied to 1 mole of acetone is preferably 3 to 30 moles, more preferably 5 to 20 moles, from the viewpoints of easiness of purification and economy of produced bisphenol A.

Further, in the production of bisphenol A in the present step, addition of a reaction solvent is not particularly required except for the case where the viscosity of the reaction liquid is too high or when the reaction is carried out at a low temperature such that solidification becomes difficult and operation is difficult.

The condensation reaction of phenol and acetone in the present step may be either batch or continuous, but it is preferable to employ a fixed bed continuous reaction method in which raw materials are continuously supplied and reacted, and a fixed phase circulation system, desirable.

The reaction tower in the fixed bed continuous reaction system may be a single reactor or may be a fixed phase multi-stage continuous reaction system in which two or more reactors 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 &} gt ;.

The temperature at the time of the reaction of phenol and acetone is preferably 50 to 100 占 폚, more preferably 55 to 90 占 폚, and still more preferably 60 to 80 占 폚. When the reaction temperature is 50 캜 or higher, the reaction rate can be sufficiently increased, the viscosity of the reaction mixture can be adjusted to an appropriate range, and the possibility of solidification of the reaction mixture can be prevented. On the other hand, when the reaction temperature is 100 캜 or lower, the reaction can be controlled and the selectivity of bisphenol A can be improved. Further, decomposition or deterioration of the catalyst can be prevented.

The pressure at the time of the reaction of phenol and acetone is preferably atmospheric pressure (0.1 MPa) to 1.5 MPa, more preferably atmospheric pressure (0.1 MPa) to 0.6 MPa.

[Step (B)]

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

In this step, it is preferable to concentrate the reaction mixture by distillation under reduced pressure using a distillation column.

Also, the concentration of the present step is mainly carried out by a first concentration step for distilling off and removing mainly unreacted acetone, water and a low boiling point substance, and a second concentration step for mainly removing unreacted phenol and the like and adjusting the concentration of the concentrate .

As the conditions of the vacuum distillation in the first concentration step, the temperature is preferably 10 to 200 占 폚, more preferably 20 to 190 占 폚, still more preferably 30 to 180 占 폚, and the pressure is preferably 10 to 90 kPa, More preferably from 20 to 80 kPa, still more preferably from 25 to 70 kPa.

As the conditions of the vacuum distillation in the second concentration step, the temperature is preferably 70 to 170 占 폚, more preferably 80 to 140 占 폚, still more preferably 85 to 130 占 폚, the pressure is preferably 4 to 70 kPa, More preferably 7 to 50 kPa, and still more preferably 10 to 30 kPa.

In addition, the temperature and pressure in the reduced-pressure distillation in the second concentration step are preferably set to be lower than the first concentration step in consideration of the boiling point of the component.

The concentration of bisphenol A in the concentrate obtained through this step is preferably 20 to 60 mass%, more preferably 20 to 40 mass%. If the concentration is 20% by mass or more, the recovery of bisphenol A by crystallization can be efficiently performed. On the other hand, if the amount is 60% by mass or less, the solidification temperature is not increased and it is possible to prevent the slurry after the crystallization from being difficult to transfer.

[Step (C)]

The step (C) is a step of crystallizing the concentrated liquid obtained in the step (B), subjecting to solid-liquid separation, and separating the solid component including adducts of bisphenol A and phenol (hereinafter also referred to as " .

As a solid crystallization method from the concentrated solution, it is preferable that the concentrated liquid immediately after the completion of the vacuum distillation before crystallization is cooled to 35 to 60 占 폚 (preferably 40 to 55 占 폚) and the solid content is crystallized into 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 a concentrated liquid and cooling is performed using latent heat of evaporation of water under reduced pressure.

Then, the slurry containing the solid content thus obtained is separated into a mother liquor containing the solid matter and the reaction by-product by a known means such as filtration or centrifugation. The equipment to be used at this time is not particularly limited, and examples thereof include a belt filter, a drum filter, a tray filter, and a centrifugal separator.

Further, after the solidification, the solid content after solid-liquid separation can be redissolved, and the solid-liquid separation may be repeated after the solidification again. By repeating the crystallization and solid-liquid separation in multiple stages, the impurities introduced into the crystal can be reduced. Examples of the resolving solution for redissolution include phenol, water, and a mixture of water and phenol. The phenol recovered from the system may be used, or the phenol separately supplied from the system may be used.

Further, the separated solids are washed and sent to the duct decomposition step, and phenol is removed from the adduct contained in the solid component, whereby high-purity bisphenol A can be obtained.

Examples of the cleaning liquid to be used at this time include phenol, water, and a mixture of water and phenol. The phenol recovered from the system may be used, or the phenol separately supplied 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 solid in terms of cleaning efficiency and loss for redissolution, circulation, recovery and reuse of the cleaning liquid.

[Air duct decomposition process]

The adducts (adducts) of bisphenol A and phenol contained in the solid component recovered by solid-liquid separation as described above are decomposed into bisphenol A and phenol by passing through an adduct decomposition step, and phenol is removed to obtain high purity bisphenol A .

In the duct decomposition process, it is preferable to firstly heat and melt the solid content including the adduct at 100 to 160 DEG C to decompose the adduct into bisphenol A and phenol, and obtain a melt containing the bisphenol A and phenol.

Subsequently, this melt is sent to an evaporation column, phenol is removed from the melt by vacuum distillation or the like, and bisphenol A in a molten state is recovered. The vacuum distillation is preferably carried out at a temperature of 150 to 190 DEG C and a pressure of 1 to 11 kPa.

It is also preferable that the recovered phenol A in the molten state is further subjected to steam stripping to remove remaining phenol.

Through these processes, high-purity bisphenol A can be obtained.

[Step (D)]

Step (D) is a step of isomerizing at least part of the mother liquor present in the system with the mother liquor obtained in step (C).

The mother liquor obtained in the step (C) has a composition of 65 to 85% by mass of phenol, 10 to 20% by mass of bisphenol A, 5 to 15% by mass of 2,4'-isomer and other impurities, Are included.

In the present invention, of the mother liquor obtained in the step (C), part of the mother liquor may be discharged out of the system, but at least part of the mother liquor present in the system after the discharge is at least partially isomerized.

As described above, at least a part of the mother liquor present in the system is isomerized to increase the concentration of the bisphenol A by dialing the impurities in the mother liquor as much as possible. Therefore, when pumping a part of the mother liquor out of the system to prevent impurities from accumulating in the system, more bisphenol A can be recovered from the purifying mother liquor and the recovery rate of bisphenol A can be improved.

The ratio of the mother liquor subjected to isomerization 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, and still more preferably 70 to 100% by mass from the viewpoint of improving the recovery rate of bisphenol A. Is 80 to 100 mass%, more preferably 90 to 100 mass%, and it is particularly preferable to subject the entire amount of the mother liquor present in the system to isomerization treatment.

From the viewpoint of improving the recovery of bisphenol A, it is preferable to subject the whole amount of the mother liquor obtained in the step (C) to isomerization treatment.

The catalyst used in the isomerization treatment is preferably a sulfonic acid type cation exchange resin. Examples of the sulfonic acid type cation exchange resin include resins used in the above-mentioned step (A).

The isomerization treatment is preferably carried out in the presence of the above sulfonic acid type cation-exchange resin at a reaction temperature of 50 to 100 占 폚 (preferably 60 to 90 占 폚) by a continuous-flow extrusion flow system.

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.

Further, a plurality of reactors for carrying out the isomerization treatment in this step may be provided in parallel. For example, the reactor for isomerization treatment for recycling the mother liquor obtained in the step (C) to the step (B) after the isomerization treatment and the reactor for the isomerization treatment for the step (E) for treating the solution after the isomerization treatment It is also possible to install it.

The solution after the isomerization treatment is sent to the step (E), but it is preferable to return a part of the solution to the step (B). By returning part of the solution after the isomerization treatment to the step (B), the bisphenol A produced by the isomerization treatment can be recovered to improve the recovery rate of the bisphenol A. Further, since the solution after isomerization contains 65 to 85% by mass of phenol, it is preferable to return the solution to the step (B) in order to evaporate this part and prepare it at the concentration of bisphenol A corresponding to the crystallization operation .

From the above viewpoint, the amount of the solution sent to the step (E) in the solution after the isomerization treatment is preferably 5 to 30 mass%, more preferably 10 to 25 mass%, and still more preferably 13 to 23 mass% (B) is preferably 95 to 70% by mass, more preferably 90 to 75% by mass, and still more preferably 87 to 77% by mass.

[Step (E)]

The step (E) is a step of crystallizing a solution after the isomerization of the step (D), followed by solid-liquid separation, and separating the solid and the mother liquid. By this step, the solid content including the adduct (adduct) of bisphenol A and phenol is crystallized and separated into solid and mother liquor.

It is preferable that the solution after the isomerization treatment is concentrated by removing part of phenol before crystallization. The concentration is preferably carried out at a temperature of 70 to 140 캜 (preferably 80 to 125 캜, more preferably 90 to 115 캜) and a pressure of 1.5 to 40 kPa (preferably 2.0 to 25 kPa, more preferably 3.0 to 15 kPa) It is preferably carried out by reduced pressure distillation. The concentration of bisphenol A in the solution after concentration is preferably 20 to 50 mass%.

As a solid crystallization method from the concentrated solution, it is preferable that the solution immediately after the completion of the reduced pressure distillation is cooled to 35 to 60 캜 (preferably 40 to 55 캜) and the solid component is crystallized to obtain a slurry. The cooling at this time can be carried out by the same method as in the above-mentioned step (C).

In addition, the slurry containing the solid content can be separated into the solid content and the mother liquid crystallized by the same method as the above-mentioned step (C).

It is preferable that the solid content (hereinafter also referred to as "recovered crystal") crystallized here is returned to the above-mentioned step (B) or step (C). The determination of the number of times contains more impurities than the crystals obtained in the above-described step (C), but the concentration of the impurities in the recovered crystals is lower than the concentration of the impurities in the reaction mixture obtained in the step (A). Thereby, by returning the recovery determination to the step (B) or the step (C), the concentration of the impurities in the reaction mixture obtained in the step (A) is lowered, and crystals of higher purity can be obtained than when the recovery crystal is not supplied.

Further, in the present invention, it is preferable that phenol recovery treatment is performed on the mother liquor from which the solid content has been removed by solid-liquid separation in the step (E), and the mother liquid after the phenol recovery treatment is sent to the step (F).

The mother liquor obtained in the step (E) has a composition of usually 45 to 70 mass% of phenol, 5 to 15 mass% of bisphenol A and 20 to 40 mass% of impurities such as 2,4'-isomer. Although the mother liquor contains a large amount of impurities such as 2,4'-isomer, it often contains more phenol than these impurities. Therefore, in order to recover the phenol contained in the mother liquor before the mother liquor is returned to the step (F) in view of the efficiency of phenol recovery, the mother liquor from which the solid content has been removed by solid-liquid separation in the step (E) .

Examples of the method for recovering phenol in the phenol recovery process include a method of recovering phenol from the column by distillation under reduced pressure using a rechargeable distillation column or the like and obtaining a residual solution containing a large amount of by- desirable.

The conditions for the vacuum distillation are preferably a temperature of 120 to 180 캜 (preferably 135 to 170 캜) and a pressure of 0.5 to 20 kPa (preferably 1.0 to 10 kPa). It is preferable that the reduced pressure distillation is carried out until the residual phenol content in the residual liquid is preferably 20% by mass or less, more preferably 2 to 15% by mass.

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

[Step (F)]

In step (F), at least a part of the mother liquor present in the system in the mother liquor obtained in step (E) is subjected to alkali decomposition treatment to recover phenol and / or p-isopropenylphenol (IPP) Phenol and / or IPP to the reactor of the step (A) without passing through the recombination reactor.

Further, in this step, alkaline decomposition treatment may be performed on the whole amount of the mother liquor present in the system in the mother liquor obtained in the step (E). However, it is preferable that phenol recovery treatment is performed on the mother liquor from which the solid content has been removed by solid-liquid separation in the step (E), and alkaline decomposition treatment is performed on the remaining mother liquor after recovery of phenol.

As described above, the mother liquor in which the solid is separated and removed in the step (E) contains many impurities such as bisphenol A, 2,4'-isomer and the like. In addition, with respect to the mother liquor after recovery of phenol from the mother liquor, the proportion of impurities such as bisphenol A, 2,4'-isomer, etc. increases. In this step, alkaline is added to these mother liquors containing a large amount of impurities, and the mother liquor is supplied to the reaction tank of the alkali decomposition reaction tower. By operating under high temperature and reduced pressure, impurities such as bisphenol A and 2,4'-isomer are decomposed into phenol and IPP.

The phenol and IPP can be recovered from the column top of the reaction column, and the impurities such as chroman compounds are converted into heavy impurities (high boiling points) and taken out from the column bottom (reaction tank) of the reaction column as tar (residue).

Both the phenol and IPP can be recovered, or only one of them can be recovered.

The alkali decomposition treatment can be carried out either continuously or batchwise.

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

As described above, the alkali decomposition treatment of at least a part of the mother liquor present in the system decomposes the 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 of phenol and acetone and is an intermediate of bisphenol A, by returning the obtained phenol and / or IPP to the step (A), it is possible to reduce the amount of phenol and acetone, which are raw materials, .

From the viewpoint of improving the recovery rate of phenol and / or IPP and reducing the amount of phenol and acetone to be supplied newly in the system, it is preferable to subject the whole amount of the mother liquor obtained in the step (E) to the alkali decomposition treatment.

Examples of the alkali used in the alkali decomposition treatment include sodium hydroxide and potassium hydroxide, and they 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, more preferably 0.05 to 2.0% by mass, based on the feed amount excluding the phenol supplied to the reaction tank.

When the alkali decomposition treatment is carried out, the temperature of the reaction tank and the distillation column is preferably 180 to 350 占 폚, more preferably 190 to 300 占 폚, and still more preferably 200 to 280 占 폚.

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

In the present invention, the phenol and / or IPP recovered from the column are condensed and liquefied and mixed with phenol and acetone as feedstocks, and then fed to the reactor of step (A). Further, the phenol and / or IPP recovered in the present step may be condensed and liquefied together with phenol recovered to the pre-treatment.

Here, when the recovered phenol and / or IPP is fed to the reactor of the process (A) via the re-combination reactor, phenol and IPP react with each other in the re-combination reactor to produce bisphenol A as described above. When the produced bisphenol A is sent to the reactor of the step (A), byproducts are generated by further reacting with IPP which is a reaction intermediate having a high reactivity, thereby causing degradation of the quality of bisphenol A produced.

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

The recovered phenol and IPP may be fed to the reactor of the step (A) via another process or reactor without interfering with the effect of the present invention unless passing through the re-combination reactor. However, And is preferably supplied to the reactor.

As described above, according to the production method of the present invention, high-quality 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 production method of the present invention is preferably 15 or less, more preferably 12 or less, still more preferably 10 or less.

[Example]

EXAMPLES The present invention will be described in more detail with reference to the following examples, which should not be construed as limiting the scope of the present invention.

In the following Examples and Comparative Examples, phenol and bisphenol A produced in the production process were quantified by HPLC analysis.

The color (APHA) of the produced bisphenol A was determined by dissolving 20 g of bisphenol A in 20 ml of ethanol, and measuring the color of bisphenol A by using a spectrophotometer (product name: U-3410 type magnetic spectrophotometer, manufactured by Hitachi Seisakusho Co., Ltd.) 4101 < / RTI >

Example 1

Fig. 2 is a process diagram of a process for producing bisphenol A of the first embodiment. Hereinafter, a method for producing bisphenol A in Example 1 will be described in accordance with the process chart shown in Fig.

A fixed-bed reactor packed with 20% by mole of sulfonic acid groups partially neutralized with 2-mercaptoethylamine to a sulfonic acid-type cation-exchange resin (product name: "DAIONON-104H", product of Mitsubishi Chemical Corporation) , A mixture of 51.9 t / h of the initial supply amount of phenol and 4.5 t / h of acetone was continuously supplied at a liquid hourly space velocity of 1.0 hr ^-1 under an ambient pressure (0.1 MPa) while maintaining the temperature of the catalyst layer at 80 ° C The feed amount of phenol to 1 mole is 7.1 mole). Then, bisphenol A was produced to obtain a reaction mixture containing the bisphenol A (step (A)).

From the resultant reaction mixture, mainly unreacted acetone, reaction-produced water and low boiling point substances were distilled off under the conditions of a temperature of 150 ° C and a pressure of 40 kPa. Subsequently, mainly phenol was distilled off under the conditions of a temperature of 90 ° C and a pressure of 10 kPa, To obtain a concentrated solution (step (B)).

The concentrate was cooled to 90 占 폚 to 45 占 폚, and the solid content including adducts of bisphenol A and phenol was crystallized and separated by a centrifugal separator. The solid matter and 11.2 t / h of mother liquor (Step (C)). The solids were washed, melted and adducted, and sent to a distillation column operated under the conditions of a temperature of 170 DEG C and a pressure of 2 kPa, and the phenol was distilled off and recovered. Then, the solution containing bisphenol A was extracted from the column bottom of the distillation column, and the remaining phenol was completely removed from the solution by steam stripping to obtain 6.3 t / h of bisphenol A.

On the other hand, the temperature of the entire amount of 11.2t / h the mother liquor separated in centrifuge 70 ℃, prepared sulfonic acid type cation exchange resin (Mitsubishi Chemical Co., Ltd. under conditions of a liquid space velocity 1hr ^-1, product name "Diamond ion -104H" ), Followed by isomerization (step (D)).

Then, a solution of 8.8 t / h in the solution after the isomerization was returned to the step of concentration in the step (B), and the remaining 2.4 t / h of the solution was concentrated under a condition of a temperature of 100 ° C and a pressure of 5 kPa to distill off some phenol, The solid content including adducts of adducts of bisphenol A and phenol was crystallized by cooling to 50 DEG C and then separated by a centrifugal separator. The solids were washed to obtain a solids of 0.7 t / h and a mother liquor of 1.7 t / h (Step (E)). This solid was melted and then returned to the concentration process of process (B).

On the other hand, in the step (E), the mother liquor from which the solid content was removed was subjected to phenol evaporation under the conditions of a temperature of 160 ° C and a pressure of 2 kPa to recover 1.3 t / h of phenol, Mother liquor).

The residual liquid (residual mother liquor) of 0.4 t / h was added to a reaction tank of an alkali decomposition reaction column having a reaction tank after addition of 10 kg / h of a 25% aqueous sodium hydroxide solution, and a temperature of 250 ° C and a pressure of 6.7 kPa , 0.21 t / h of phenol and p-isopropenylphenol (IPP) were obtained from the top of the reaction tower and 0.17 t / h of tar (residue) was obtained from the bottom of the reaction tower (reaction tank). Then, the phenol and IPP obtained from the column top were mixed with the phenol recovered in the other process and directly supplied to the stationary phase reactor of the step (A) (step (F)).

The cycle comprising the above process was repeated and the feed phenol and acetone were adjusted so that the amount of bisphenol A produced was kept constant at 6.3 t / h. After a certain period of time, the amount of phenol supplied was 5.40 t / h, The amount was 1.70 t / h. The color (APHA) of the produced bisphenol A was 10.

Comparative Example 1

3 is a process chart of a process for producing bisphenol A of Comparative Example 1. Bisphenol A was prepared according to the process shown in Fig.

That is, except that the remaining liquid (residual mother liquor) of 0.4 t / h remaining after recovering the phenol from the mother liquor from which the solid content was removed in the step (E) of Example 1 was discarded without going through the above step (F) 1 was adjusted to produce 6.3 t / h of bisphenol A by the same production method as in Example 1.

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

The prepared bisphenol A was of high quality in the same manner as in Example 1, but in the production method of Comparative Example 1, it is necessary to supply a larger amount of the supplied phenol at 0.15 t / h and the supplied acetone amount at 0.05 t / h than the production method of Example 1 .

That is, the production method of Comparative Example 1 requires as much raw material as 1,200 tons of supplied phenol per year and 400 tons of supplied acetone, compared with Example 1.

Comparative Example 2

4 is a process chart of a process for producing bisphenol A of Comparative Example 2. Fig. Bisphenol A was prepared according to the process shown in Fig.

That is, in the step (F) of Example 1, phenol obtained from the top of the evaporation column and IPP are mixed with phenol recovered in another step, and bisphenol A is produced by reacting phenol with IPP in a re- Was prepared in the same manner as in Example 1 except that the reaction product containing the bisphenol A produced in Example 1 was fed to the fixed bed reactor of Process (A) so that 6.3 t / h of bisphenol A was produced.

After a lapse of a certain time, the amount of phenol supplied 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 produced bisphenol A was 20, which is a result of degradation in quality compared to the bisphenol A prepared in Example 1. This is considered to be caused by the fact that the bisphenol A produced in the re-combination reactor is fed to the reactor, for example, by-products obtained by further reaction of IPP and bisphenol A present in the reactor remain.

According to the process for producing bisphenol A of the present invention, high-quality bisphenol A can be produced, and the amount of raw material to be supplied can be effectively reduced. The obtained bisphenol A can be used as a raw material for engineering plastics such as polycarbonate resins and polyarylate resins.

Claims

A process for producing bisphenol A comprising the following steps (A) to (F).
Process (A): A process for producing a bisphenol A and a reaction mixture containing bisphenol A in a reactor for condensing excess phenol and acetone in the presence of an acid catalyst
Step (B): a step of concentrating the reaction mixture obtained in the step (A) to obtain a concentrate
Step (C): A step of crystallizing the concentrate obtained in the step (B), solid-liquid separation and separating the solid content including the adduct of bisphenol A and phenol with the mother liquid
Step (D): a step of isomerizing at least a part of the mother liquor present in the system in the mother liquor obtained in the step (C)
Step (E): a step of crystallizing a solution after the isomerization of the step (D), followed by solid-liquid separation, and separating the solid and the mother liquid
Step (F): In the mother liquor obtained in the step (E), at least part of the mother liquor present in the system is subjected to alkali decomposition treatment to recover the phenol and / or p-isopropenylphenol and recover the recovered phenol and / Step of feeding p-isopropenylphenol to the reactor of process (A) without passing through a re-combination reactor

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

3. The method according to claim 1 or 2, wherein 5 to 30 mass% of the solution after the isomerization of the step (D) is sent to the step (E), 95 to 70 mass% of the solution is returned to the step (B) Process for the production of bisphenol A.

4. Process according to any one of claims 1 to 3, characterized in that in step (F) the recovered phenol and / or p-isopropenylphenol is fed directly to the reactor of step (A) Way.

The method according to any one of claims 1 to 4, wherein phenol recovery treatment is performed on the mother liquor from which the solid content has been removed by solid-liquid separation in the step (E), and the mother liquid after the phenol recovery treatment is sent to the step (F) Gt;

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