WO2004108643A1

WO2004108643A1 - Process for producing bisphenol a

Info

Publication number: WO2004108643A1
Application number: PCT/JP2004/007885
Authority: WO
Inventors: Jun Kohiruimaki; Shuichi Masuda
Original assignee: Idemitsu Kosan Co., Ltd.
Priority date: 2003-06-04
Filing date: 2004-06-01
Publication date: 2004-12-16
Also published as: TWI353973B; TW200504002A; JP4398674B2; JP2004359594A; CN1795155A; CN1331831C

Abstract

A bisphenol A/phenol adduct is separated through crystallization from a reaction mixture. The resultant mother liquor is wholly subjected to isomerization and then recycled to a condensation reaction step, a concentration step, or a crystallization/solid-liquid separation step. Blowing is conducted simultaneously with the recycling in order to prevent impurities from accumulating in the system. Thus, bisphenol A and phenol are recovered from the liquid resulting from the isomerization, whereby high-quality bisphenol A can be efficiently produced.

Description

Bisphenol A production method

The present invention relates to a method for producing bisphenol A, and more particularly, to a method for efficiently producing high-quality bisphenol A from phenol and acetone. Background art

Bisphenol A is an important compound as a raw material for epoxy resin or polycarbonate resin, and its use and demand have been increasing in recent years. To obtain high quality resin, colorless and high purity bisphenol A is required.

Bisphenol A is usually produced by reacting phenol with acetone in the presence of an acidic catalyst. A typical example of the acidic catalyst is a strongly acidic cation exchange resin. The reaction product contains, in addition to bisphenol A, unreacted phenol, unreacted acetone, reaction product water, and by-products such as coloring substances. The main reaction by-products are 2- (2-hydroxyphenyl) -12- (4-hydroxyphenyl) propane (hereinafter sometimes referred to as 2,4'-isomer) and trimethyl There are indane, dianine's compound, trisphenol, horifenol and coloring substances. These substances are not preferred because they lower the performance of resins and the like produced using bisphenol A as a raw material.

As one method for recovering high-purity bisphenol A from the reaction mixture, unreacted acetone, reaction water and some unreacted phenol are recovered from the reaction product. After removing the alcohol by distillation or the like, the remaining concentrated mixture is cooled to crystallize bisphenol A as an adduct with phenol (adduct), and the crystals (adduct crystals) are converted into reaction by-products. After separation from the mother liquor containing bisphenol A, there is a method of recovering bisphenol A by removing phenol (for example, Japanese Patent Application Laid-Open Nos. 2-28126 / 1990 and 133-132850 / 1988). No.).

In the mother liquor from which the adduct crystals were separated, many phenols and bisphenol A were present in addition to the reaction products such as 2,4'-isomer, trimethylindane, dianine compound, trisphenol, polyphenol and coloring substances. Since it is contained, this mother liquor can be circulated to the reaction system. However, if these reaction by-products are circulated as they are, they accumulate in the system, which deteriorates the crystal and thus the purity and color of the product.

For this reason, there is a method of further concentrating the mother liquor to take out crystals (recovered crystals) and supplying the crystals to a crystallization step of a reaction product solution (for example, see Japanese Patent Publication No. 52-46946). However, the mother liquor excluding the recovered crystals still contains a large amount of 2,4′-isomer and trisphenol which can be converted into bisphenol A, but at the same time, polyphenol and the like which cannot be recycled to any part of the process. It must be disposed of because it contains a lot of color and substances.

On the other hand, a method in which the 2,4'-isomer in the mother liquor from which the adduct crystals have been separated is isomerized to bisphenol A with an acid catalyst and circulated (for example, see US Pat. No. 4,400,555). ) Or a part of the mother liquor isomerized, and the remaining mother liquor is further concentrated to remove crystals (recovered crystals), and phenol is recovered from the mother liquor (recovered mother liquor) from which the recovered crystals have been removed. Is known (for example, refer to Japanese Patent Application Laid-Open No. H8-33290).

However, in the method described in the above-mentioned U.S. Pat. No. 4,400,555, since impurities such as polyphenols and coloring substances are circulated as they are, it is necessary to accumulate in the system and obtain a high-purity product. Can not. Also, prevent accumulation of impurities Therefore, there is a method of purging a part of the mother liquor from which the adduct crystals are separated, but phenol and bisphenol A, which are contained in a large amount in the purge mother liquor, are lost.

On the other hand, according to the method described in Japanese Patent Application Laid-Open No. H08-33290, bisphenol A and phenol are recovered when a part of the mother liquor from which the adduct crystal is separated is purged. Due to the low concentration of bisphenol A and the high concentration of impurities in the mother liquor, the recovery of bisphenol A is low and many of the isomers that can be converted to bisphenol A must be discarded. Disclosure of the invention

Under these circumstances, an object of the present invention is to provide a method for efficiently recovering phenol and bisphenol A from a mother liquor from which an adduct crystal has been separated, and efficiently producing high-quality bisphenol A. is there.

The present inventors have conducted intensive studies to solve the above problems, and as a result, in a method for producing bisphenol A by a condensation reaction of phenol and acetone, an adduct of bisphenol A and phenol from a reaction mixture was obtained. After the whole amount of the mother liquor after crystallization separation of isomerized, it is recycled to the condensation reaction step, concentration step or crystallization / solid-liquid separation step, and is blown to prevent the accumulation of impurities in the system. Bisphenol A and phenol are further recovered from a part of the solution subjected to the chlorination treatment, whereby phenol and bisphenol A are efficiently recovered from the mother liquor, and high-quality bisphenol A can be efficiently obtained. The present invention has been completed.

That is, the present invention provides the following method for producing bisphenol A.

1. (1) A condensation reaction step in which an excessive amount of phenol and acetone are subjected to a condensation reaction in the presence of an acidic catalyst, and (2) a reaction mixture obtained in the condensation reaction step is concentrated. (3) cooling the concentrated solution obtained in the concentration step to crystallize an adduct of bisphenol A and phenol, and separating the adduct and mother liquor into a crystallization / solid-liquid separation step And (4) the method for producing bisphenol A, which comprises removing the phenol from the adduct of bisphenol A and phenol and recovering bisphenol A, wherein the (3) crystallization / solid-liquid separation step After the whole amount of the mother liquor obtained in the above step is brought into contact with an isomerization catalyst and subjected to isomerization treatment, a part of the isomerized solution is subjected to the above-mentioned (1) condensation reaction step, (2) concentration step and (3) crystallization · A process for producing bisphenol A, comprising recycling to at least one of the solid-liquid separation steps and recovering bisphenol A and phenol from the remaining isomerized solution.

2. Concentrate the remaining isomerized solution and cool to crystallize the adduct of bisphenol A and phenol. After solid-liquid separation, the adduct is concentrated and Z or crystallization / solid-liquid separation The method for producing bisphenol A according to 1 above, wherein the phenol is recycled to the process and phenol is recovered from the liquid phase. BEST MODE FOR CARRYING OUT THE INVENTION

In the present invention, the entire amount of the mother liquor from which the adduct crystals have been separated is isomerized to convert the impurities in the mother liquor to bisphenol A as much as possible, thereby increasing the concentration of bisphenol A and lowering the impurity concentration. As a result, the recovery of bisphenol A can be increased, and the high-boiling components to be purged are reduced when purging a part of the system to prevent the accumulation of impurities in the system. can do.

The steps after this isomerization treatment can be divided into (5) isomerization treatment step, (6) adduct collection step of blow isomerization liquid, and (7) phenol collection step of adduct collection mother liquor.

Hereinafter, each step will be described in detail. (1) Condensation reaction step

The raw materials phenol and acetone are reacted in a stoichiometric excess of phenol. The molar ratio of phenol to acetone is phenol / acetone = 3 to 30, preferably 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 IVPa. As the catalyst, a strongly acidic cation exchange resin such as a sulfonic acid type is usually used.

Further, a catalyst obtained by neutralizing a part of the strongly acidic cation exchange resin catalyst with a cocatalyst such as mercaptoalkylamine may be used. For example, 2-mercaptoethylamine, 3-mercaptopropylamine, N, N-dimethyl-13-mercaptopropylamine, N, N-di-1n-butyl-14-mercaptobutyramine, 2,2-dimethyl Those obtained by neutralizing 5 to 30 mol% of sulfonic acid groups with thiazolidine or the like can be mentioned.

The condensation reaction between phenol and acetone is carried out by a continuous and push-flow fixed bed flow system or a suspension bed batch system. In the case of the fixed bed flow method, the liquid hourly space velocity of the raw material liquid supplied to the reactor is 0.1 SSO hr- ¹ . In the case of using a batch suspension system, the amount of the resin catalyst is generally in the range of 20 to 100% by weight with respect to the raw material solution, although it varies depending on the reaction temperature and the reaction pressure. About 5 to 5 hours.

(2) Concentration process

The reaction mixture from the condensation reaction step is usually concentrated in two steps. In the first concentration step, unreacted acetone, reaction water and the like are removed by a method such as distillation under reduced pressure. The vacuum distillation is carried out at a temperature of 30 to 180 ° C and a pressure of 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 Bisufuwenoru A at this time is preferably 20 to 60 weight ^_0/0. Bisphenol A concentration of 20 If the amount is less than 60% by weight, the yield will be low, and if it is more than 60% by weight, the solidification temperature will be high, and there will be a problem that the material cannot be transported. Therefore, usually, in the first concentration step, the concentration of the reaction mixture is adjusted to the above concentration by pre-concentration. Usually, this second concentration step is preferably carried out under the conditions of a pressure of 4 to 40 kPa and a temperature of 70 to 140 ° C.

(3) Crystallization and solid-liquid separation process

The concentrate from the concentration step is usually cooled from 70 to 140 ° C to 35 to 60 ° C, and the adduct of bisphenol A and phenol is crystallized to form a slurry. . Cooling is performed by heat removal by evaporation of water added to the external heat exchanger and the crystallizer.

Next, the slurry-like liquid is subjected to solid-liquid separation. The composition of the mother liquor obtained in the crystallization / solid-liquid separation process is usually phenol: 65 to 85% by weight, bisphenol A: 10 to 20% by weight, 2,4 'monoisomer, etc. By-product: It is 5 to 15% by weight and contains a lot of impurities such as 2, 4 'monoisomer.

Conventionally, a part of the mother liquor has been purged to prevent accumulation of impurities. However, in the present invention, the entire amount of the mother liquor is treated in the isomerization step to recover phenol and bisphenol A contained in the mother liquor.

The adduct recovered by the solid-liquid separation is then sent to the adduct decomposition step to remove the phenol to obtain high-purity bisphenol A.

The solid components mainly composed of the adduct that has been filtered and deposited on the filter surface of the solid-liquid separation device are subjected to washing with a washing liquid. As the washing liquid, phenol collected by evaporation, raw phenol, water, a mixed solution of water and phenol, and the same as a saturated phenol solution of bisphenol A can be used. Naturally, the larger the amount of cleaning solution used, the better in terms of cleaning efficiency.However, from the viewpoint of re-dissolution loss of crystals, circulation, recovery, and reuse of the cleaning solution, it is natural. There is an upper limit, and usually about 0.1 to 10 times the amount of crystals on a weight basis is most efficient.

After crystallization and solid-liquid separation, the crystals may be redissolved and crystallization and solid-liquid separation may be repeated again. By repeating this crystallization and solid-liquid separation in multiple stages, the impurities taken into the adduct crystals gradually decrease.

In this case, the solution for re-dissolution and the washing solution for solid components mainly composed of adduct obtained by solid-liquid separation include phenol, raw material phenol, water, water-phenol mixture, and phenol collected by evaporation. The same solution of phenol A in saturated phenol can be used for each step.

The solid-liquid separation device used in the solid-liquid separation is not particularly limited as long as it is a commonly used device, but a belt filter, a drum filter, a tray filter, a centrifuge, or the like is used.

(4) Adduct decomposition process

The adduct of bisphenol A and phenol recovered by the solid-liquid separation described above is converted to high-purity bisphenol A by removing the phenol in the adduct decomposition step. For example, as described in JP-A-2-282126 and JP-A-63-132850, the adduct is generally used in a form of 100 to Decomposes into bisphenol A and phenol by heating and melting at 160 ° C. Most of the phenol is removed from this melt using an evaporator and the remaining phenol is removed by steam stripping. To obtain bisphenol A.

(5) Isomerization process

The liquid phase (mother liquor) obtained in the crystallization / solid-liquid separation process is then supplied in its entirety to the isomerization process, where the reaction by-products in the mother liquor are isomerized. Part of the isomerized solution is recycled to at least one of the condensation reaction step, the concentration step, and the crystallization / solid-liquid separation step. In particular, the isomerized solution contains phenol Since it contains 5% by weight, it is preferable to feed the above-mentioned concentration step in order to evaporate a part thereof and adjust the concentration of bisphenol A to a concentration suitable for the crystallization operation. In the isomerization treatment, a sulfonic acid type cation exchange resin is usually used, and the reaction space is 50 to 100 ° C. speed is carried out at 0. 2~ 5 0 hr ^1.

This isomerization treatment step may be plural in parallel. For example, an isomerization treatment step for recycling the isomerization treatment liquid to a condensation reaction step, a concentration step or a crystallization / solid-liquid separation step, and an isomerization treatment liquid for blowing to prevent accumulation of impurities. It is also possible to divide and install the isomerization treatment step.

(6) Adduct recovery process for blow isomerization solution

The isomerized solution to be purified to prevent the accumulation of impurities is concentrated and then cooled to crystallize an adduct of bisphenol A and phenol (adduct). After solid-liquid separation, the adduct is Recycle to the concentration step and Z or crystallization / solid-liquid separation step.

The blow isomerization solution is concentrated by removing a part of the phenol using an evaporator or the like. The concentration of bisphenol A after concentration is about 20 to 50% by weight, the pressure is 5.3 to 40 kPa, and the temperature is 70 to: L40 ° C.

The concentrate of the blow-isomerized solution thus obtained is usually cooled from 70 to 140 ° C. to 35 to 60 ° C. to crystallize the adduct and to be separated into a solid and a liquid.

The crystals obtained by this solid-liquid separation operation (hereinafter referred to as recovered crystals) are returned to the above-mentioned (1) concentration step (second concentration step) or crystallization / solid-liquid separation step. The recovered crystal contains more impurities than the solid phase (crystal) obtained in the crystallization / solid-liquid separation process. However, since the concentration of impurities in the recovered crystals is lower than the concentration in the reaction solution obtained in the condensation reaction step, the recovered crystals are crystallized and supplied to the solid-liquid separation step. In this case, the concentration of the reaction by-products becomes lower, and higher purity crystals can be obtained than when no recovered crystals are supplied.

(7) Step of recovering phenol from mother liquor

On the other hand, the composition of the blowing isomerized liquid Adakuto recovery step obtained in liquid-phase portion of the (mother liquor), phenol 4 5-7 0 weight ^_0/0, bisphenol A. 5 to 1 5% by weight, 2, 4 'By-products such as monoisomer are 20 to 40% by weight, and contain a large amount of 2,4' monoisomer, which is a reaction by-product, but also a large amount of phenol.

Therefore, phenol should be recovered from this liquid phase by using a packed distillation tower, etc., and the high-boiling compounds containing a large amount of by-products and coloring substances as residues should be discharged out of the system. As a result, there is no accumulation of impurities in the system, and high-quality bisphenol A can be obtained as a product. High-boiling compounds discharged out of the system are disposed of by an incinerator. The phenol recovery treatment is usually performed at a pressure of 4 to 33 kPa and a temperature of 120 to 180 ° C, and the amount of residual phenol in the residue is 20% by weight or less, preferably 5 to 5% by weight. Perform until 18% by weight. The phenol recovered here can be reused, for example, as a washing solution or a raw material for a reaction in a crystallization-solid-liquid separation step.

Hereinafter, the method of the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.

In the following examples,% is% by weight unless otherwise specified. Phenols and bisphenol A etc. were quantified by HPLC analysis. The hue was determined by dissolving 20 g of bisphenol A in 20 ml of ethanol and measuring the absorbance with a spectrophotometer.

Example 1

Three packed bed reactors with an inner diameter of 40 mm and a height of 5 ° O mm are connected in series, and a sulfonic acid type ion exchange resin (Mitsubishi Chemical Corporation, Diaion S K-104H) was partially neutralized with 2-mercaptoethylamine to partially neutralize 20 mol% of sulfonic acid groups, and was filled in 5.5 liters. A mixture of phenol and acetone (phenol acetone = 10/1 (molar ratio)) was passed continuously for 100 hours at a liquid hourly space velocity of 1 hr- ¹ while maintaining the temperature of the catalyst layer at 80 ° C. .

Unreacted acetone, reaction water and a small amount of phenol were removed from 20 kg of the reaction product liquid obtained from this reactor under reduced pressure. The obtained concentrate contained 30.5% of bisphenol A, 3.8% of 2,4′-isomer and trisphenol, and 3.4% of other impurities. The concentrate was cooled from 90 ° C to 45 ° C to precipitate crystals, which were separated by a centrifugal separator to obtain 2830 g of crystals and 6170 g of mother liquor.

Next, the obtained crystals were melted and sent to a distillation column operated at 2 kPa and 170 ° C. to remove most of the phenol by distillation. Bisphenol A was extracted from the bottom of the column, and the remaining phenol was completely removed by steam stripping to obtain 1,640 g of a bisphenol A product. The obtained bisphenol A contained 0.04% of 2,4 ′ monoisomer and 0.025% of other impurities, and its hue was 10APHA.

The mother liquor separated by the centrifugal separator was converted to a sulfonic acid type cation exchange resin (Mitsubishi Chemical Corporation, Diaion SK-104H) under the conditions of a temperature of 7 ° C and a liquid hourly space velocity of lhr- ^1. It was brought into contact and subjected to isomerization. This isomerization solution contained 14.0% of bisphenol A, 4.2% of 2,4'-isomer and trisphenol, and 4.9% of other impurities, and was obtained in a quantity of 6130 g. . Part of the phenol was distilled off from the 490 g isomerized solution under reduced pressure, and 50.8% of phenol, 29.8% of bisphenol A, and impurities (including 2,4'-heterogeneous organism) 19.4% 230 g of a concentrated solution containing The concentrated solution was cooled, and the recovered crystals were crystallized and separated by a centrifuge. Mother liquor was obtained. The recovered crystals contained 45.6% of phenol, 51.1% of bisphenol A, and 3.3% of impurities. The mother liquor from which the recovered crystals were separated contained 67.8% of phenol, and was distilled at a temperature of 16.5 ° (at a pressure of 14 kPa) to recover 70 g of phenol. .

Example 2

In the same manner as in Example 1, 19.5 kg of the reaction product solution was distilled under reduced pressure to remove unreacted acetone, produced water, and a small amount of phenol, and then the isomerized solution obtained in Example 1 was removed. 56.40 g and 105 g of the recovered crystals were added and dissolved. This solution contained 62.3% of phenol, 0.6% of bisphenol A3, 3.8% of 2, A'-isomer and trisphenol, and 3.3% of other impurities. This mixed solution was cooled from 90 ° C. to 45 ° C. to precipitate crystals, which were separated by a centrifugal separator to obtain 365 g of crystals and 7930 g of mother liquor. .

The crystals were subjected to dephenol treatment in the same manner as in Example 1 to obtain 210 g of bisphenol A product. The obtained bisphenol A contains 0.03% of 2,4'-isomer and 0.023% of other impurities, and the hue of the obtained bisphenol A is not recycled. It was 10 APHA equivalent to 1. Comparative Example 1

The same treatment as in Example 1 was performed from the reaction to the crystallization / solid-liquid separation step, to obtain 2830 g of crystals and 6170 g of mother liquor. 490 g of this mother liquor was partially distilled off under reduced pressure to remove phenol, 52.9% of phenol, 6.1% of bisphenol A, and impurities (including 2,4 'monoisomer). 230 g of a concentrated solution containing 1.0% was obtained. The concentrate was cooled, and the recovered crystals were crystallized and separated by a centrifugal separator to obtain 80 g of crystals and 145 g of mother liquor. This recovered crystal contained 45.6% of phenol, 0.1% of bisphenol A, and 4.3% of impurities. The mother liquor from which the recovered crystals were separated contained 63.4% of phenol, which was distilled under the conditions of a temperature of 16 ° C and a pressure of 14 kPa, and 55 g were recovered.

Comparative Example 2

In the same manner as in Example 1, 19.5 kg of the main reaction product was obtained. To this, 5660 g of the isomerized solution obtained in Comparative Example 1 was added and distilled under reduced pressure to remove unreacted acetate, produced water and a small amount of phenol. Thereto, 80 g of the crystal obtained in Comparative Example 1 was added and dissolved. This solution contained 61.0% of phenol, 0.6% of bisphenol A, 4.1% of 2,4′-isomer and trisphenol, and 4.3% of other impurities. The mixed solution was cooled from 90 ° C. to 45 ° C. to precipitate crystals, which were separated by a centrifuge to obtain 3570 g of crystals and 8010 g of mother liquor.

The crystals were subjected to dephenol treatment in the same manner as in Comparative Example 1 to obtain 2100 g of a product of bisphenol A. The obtained bisphenol A contained 0.05% of 2,4′-isomer and 0.03% of other impurities, and its hue was 2 OA PHA.

As can be seen from the above Example 1 and Comparative Example 1, after the mother liquor to be purged according to the present invention in Example 1 was subjected to an isomerization treatment under the same amount of mother liquor to be purged, bisphenol A and phenol As a result, the amount of recovered bisphenol A was increased by 17% and that of phenol by 33% compared to the comparative example, and the concentration of impurities in the recovered crystals was reduced. It turns out that it does not worsen. Industrial applicability

According to the method of the present invention, in the step of isomerizing and recycling reaction by-products in the mother liquor, phenol and bisphenol A can be efficiently converted from the mother liquor containing a large amount of impurities which has been purged to prevent accumulation of impurities. Colorless, high-quality bisphenol A, which can be recovered well and does not accumulate impurities in the system. Is obtained as a product.

Further, according to the method of the present invention, it is possible to efficiently recover phenol and bisphenol A. As a result, it is possible to reduce the load of waste oil treatment, and to economically produce bisphenol A. Can be.

Claims

The scope of the claims

1. (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 concentration step of condensing the reaction mixture obtained in the condensation reaction step, (3) a concentration step By cooling the concentrated solution obtained in the above, an adduct of bisphenol A and phenol is crystallized, and the crystallization and solid-liquid separation step of separating the adduct and mother liquor and (4) the reaction between bisphenol A and phenol In the method for producing bisphenol A, which comprises a step of decomposing the adduct to remove phenol and recover bisphenol A, the total amount of the mother liquor obtained in the above (3) Crystallization After the isomerization treatment by contacting, a part of the isomerized solution is subjected to at least one of the above-mentioned (1) condensation reaction step, (2) concentration step, and (3) crystallization / solid-liquid separation step. Recirculate and the remaining isomers A method for producing bisphenol A, comprising recovering bisphenol A and phenol from a chlorination solution.

2. Concentrate the remaining isomerized solution and cool to crystallize the adduct of bisphenol A and phenol. After solid-liquid separation, the adduct is concentrated and / or crystallized. 2. The method for producing bisphenol A according to claim 1, wherein the phenol is recycled from the liquid phase while being recycled to the separation step.