JPH10218814A - Production of bisphenol a - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing bisphenol A in high yield by limiting the amount of water in a recombination step, comprising a formation step for forming the bisphenol A by carrying out condensation reaction of acetone with phenol in the presence of a specific catalyst, a crystallization step for cooling the product, a degradation step for degrading a mother liquor and the recombination step. SOLUTION: This method for producing bishenol A in high yield comprises limiting of the amount of water to <=0.1wt.% in a recombination step after forming the bisphenol A by carrying out a condensation reaction of acetone with phenol in the presence of a strong acid ion exchange resin partially modified by a sulfur-containing amine compound (e.g. 2-mercaptoethylamine).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing bisphenol A.

[0002]

It is known to produce bisphenol A by reacting acetone and excess phenol in the presence of an acid catalyst. In this method, bisphenol A
Is obtained as a phenol solution, which is subjected to a distillation treatment to remove a low-boiling fraction contained therein and excess phenol, and then sent to a crystallization step, where it is cooled,
Separated as bisphenol / phenol crystal adduct. On the other hand, in the crystallization step, a phenol solution containing by-products such as bisphenol A and its isomers and a very small amount of colored impurities is obtained as a mother liquor. When this mother liquor is recycled and used as it is in the bisphenol A production step,
Since the accumulation of the by-products and the colored impurities occurs, it is necessary to remove the by-products and the impurities.
Therefore, at the time of recycling and recycling the mother liquor to the bisphenol A production step, at least a part of the mother liquor is separated and heated in the presence of an alkaline catalyst to decompose into phenol and isopropenylphenol, and then these compounds are recombined in the recombination step. Is reacted to convert to bisphenol A, and the bisphenol A is circulated to a bisphenol A production step for performing a condensation reaction between phenol and acetone. By the way, in the decomposition step, the reaction product liquid from the recombination step is condensed with acetone and phenol in order to by-produce a substance serving as a catalyst poison component with respect to the catalyst used in the condensation reaction step of acetone and phenol. When circulating to the reaction step, there arises a problem that the catalyst in the condensation reaction step is poisoned and its activity is reduced. The catalyst whose activity has been reduced needs to be replaced with a new catalyst, but such replacement of the catalyst requires much trouble and is economically disadvantageous.

[0003]

SUMMARY OF THE INVENTION The present invention is to decompose a mother liquor obtained in the crystallization step of bisphenol A / phenol crystal adduct under an alkaline catalyst, and then convert the resulting decomposition product to a strongly acidic ion exchange resin catalyst. Contacting the phenol and isopropenyl phenol contained in the decomposition product solution with bisphenol A, and circulating the obtained recombination reaction solution to a condensation reaction step of acetone and phenol. An object of the present invention is to provide a method for effectively suppressing catalyst activity deterioration in a reaction step.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, surprisingly, the water in the reaction product solution in the recombination step was reduced to 0.1% by weight or less. It has been found that the above problem can be solved by controlling, and the present invention has been completed. That is, according to the present invention, (i) a bisphenol A producing step in which acetone and an excess amount of phenol are subjected to a condensation reaction in the presence of a strongly acidic ion exchange resin catalyst partially modified with a sulfur-containing compound, A) a crystallization step of cooling the reaction product of bisphenol A and phenol obtained in the bisphenol A production step to produce a bisphenol A / phenol crystal adduct and a mother liquor; and (iii) an alkaline catalyst A decomposition step of decomposing bisphenol A and its isomers in the mother liquor into phenol and isopropenyl phenol, and (iv) decomposing the decomposition product liquid obtained in the decomposition step with a strongly acidic ion-exchange resin. Contacting with a catalyst, phenol contained in the decomposition product solution and isopropenyl phenol are recombined to form bisphenol A, (V) circulating the obtained recombined liquid to the bisphenol A producing step, wherein the amount of water in the reaction product liquid in the recombined step is controlled to 0.1% by weight or less. A method for producing bisphenol A is provided.

[0005]

Next, the present invention will be described with reference to the drawings. FIG. 1 shows an example of a flow sheet for implementing the method of the present invention. In this figure, 1 is a condensation reaction device of acetone and phenol, 2 is a distillation column, 3 is a crystallization device, 4 is a distillation column, 5 is a decomposition device (purge device), and 6 is a recombination device (scavenger device). Is shown. In order to carry out the method of the present invention according to FIG. 1, the raw material phenol is supplied to the condensation reactor 1 through the line 11, the raw material acetone is supplied through the line 12, and the condensation is circulated through the line 14. Acetone is supplied and further circulated bisphenol A is supplied through line 15. The condensation reaction device 1 is filled with a catalyst composed of a strongly acidic ion exchange resin partially modified with a sulfur-containing amine compound. In this case, a sulfonic acid type cation exchange resin can be used as the strongly acidic ion exchange resin. Such a sulfonic acid type cation exchange resin is conventionally well-known, and a gel type or a porous type can be used, but a gel type is preferably used. The degree of crosslinking is preferably set in the range of 2 to 16%, preferably 2 to 6%. Further, the average particle size is usually 0.1.
It is 2 to 2 mm, preferably 0.4 to 1.5 mm. Such an unmodified sulfonic acid type cation exchange resin is already commercially available, and, for example, Amberlite and Amberlyst manufactured by Rohm and Haas Co., Ltd., Dayaion manufactured by Mitsubishi Kasei, and the like can be preferably used.

The sulfonic acid type cation exchange resin is partially modified with a sulfur-containing compound to be used as a catalyst. In this case, the sulfur-containing compound is also a well-known compound such as 3-mercaptomethyl. Mercaptoalkylpyridines such as pyridine, 3-mercaptoethylpyridine and 4-mercaptoethylpyridine; 2-mercaptoethylamine, 3-mercaptobutylamine;
Mercaptoalkylamines (or aminoalkylmercaptans) such as 3-n-propylamino-1-propylmercaptan; thiazolidine, 2,2-dimethylthiazolidine, cycloalkylthiazolidine, 2-methyl-2-
Thiazolidine such as phenylthiazolidine and 3-methylthiazolidine; and aminothiophenol such as 1,4-aminothiophenol. Particularly preferably, 2-
Mercaptoethylamine and 2,2-dimethylthiazolidine. The above-mentioned sulfur-containing amine compound can be an addition salt of an acidic substance such as hydrochloric acid or a quaternary ammonium salt.

In the condensation reaction device 1, a condensation reaction between acetone and phenol occurs, and bisphenol A is produced. The reaction temperature is higher than the melting point of phenol, usually 40 to 100 ° C, preferably 55 to 85 ° C.
The reaction pressure is from 1 to 1.5 atm, preferably from normal pressure to slight pressure. The reaction time is 15-200 minutes, preferably 5
0-120 minutes. The amount of phenol used is 8 to 20 mol, preferably 10 to 16 mol, per 1 mol of acetone. The reaction product liquid obtained in the condensation reaction device 1 is sent to the distillation tower 2 through the line 16, where it is subjected to distillation treatment and separated into a phenol solution containing acetone, water, phenol and bisphenol A. Acetone line 1
4 and circulated to the condensation reactor 1,
It is discharged out of the system through 8. Phenol on line 17
Through the crystallization device 3 as washing phenol.

[0008] The phenol solution containing bisphenol A separated from the low-boiling fraction in the distillation column 2 is supplied to a line 19
To the crystallizer 3 where it is cooled. This produces a bisphenol A / phenol crystal adduct and mother liquor. The bisphenol A / phenol crystal adduct is separated from the mother liquor by a solid-liquid separation method, washed with washing phenol, and recovered through line 20. The mother liquor obtained in the crystallizer 3 is bisphenol A
And a phenol solution containing by-products thereof, and the by-products include bisphenol A isomers such as 2,4'-bisphenol A, trisphenol, and a small amount of colored impurities. This mother liquor is sent to a distillation column 4 through a line 21 and a line 23, where it is subjected to a distillation treatment, and a phenol fraction contained in the mother liquor is separated as a low-boiling fraction. Is condensed.

An aqueous solution of an alkaline substance is introduced through a line 24 near the bottom of the distillation column 4. In the alkaline aqueous solution introduced into the distillation column, the water is distilled from the top of the column, while the alkaline substance is passed through the line 26 together with the bottom fraction (bisphenol A fraction) of the distillation column 4 through the decomposition device. Sent to 5. The decomposition device 5 is a device having a structure such as a reactive distillation device. The bottom fraction of the distillation column 4 introduced into the cracker 5 is heated here in the presence of an alkaline substance. By this heating, bisphenol A and its isomer contained in the bottom fraction are decomposed into phenol and isopropenylphenol. The reaction in this case is represented by the following equation.

Embedded image

Embedded image The reaction formula (1) shows a decomposition reaction of bisphenol A, and the reaction formula (2) shows a decomposition reaction of a bisphenol A isomer. Bisphenol A and its isomers all decompose into phenol and isopropenylphenol.

Examples of the alkaline substance include hydroxides, oxides, carbonates, various phenol salts of alkali metals such as sodium and potassium, hydroxides, oxides and carbonates of alkaline earth metals such as calcium and magnesium. And various phenol salts. These alkaline substances have a concentration of 0.005 to 0.8% by weight, preferably 0.0
It is introduced near the bottom of the distillation column 4 as an aqueous solution of 1 to 0.5% by weight. The reaction temperature in the decomposition device 5 is 200 to 3
The temperature is 50 ° C, preferably 200 to 300 ° C. The reaction pressure is 5 torr to normal pressure, preferably 10 to 150 torr. In the decomposer 5, bisphenol A and its isomers are decomposed as described above, but at the same time, high-boiling tar-like substances are by-produced. This tar-like substance is discharged from the bottom of the decomposer 5 through the line 28 to the outside of the system. The decomposition product liquid comprising phenol and isopropenylphenol obtained in the decomposition device 5 is introduced into the recombination device 6 through the lines 27 and 30. Also, the condensate containing phenol condensed in the condenser 7 is supplied to the recombination apparatus through a line 29.

The recombination unit 6 is filled with a strongly acidic ion exchange resin catalyst, and the phenol isopropenylphenol introduced into the recombination unit 6 comes into contact with this catalyst to cause a condensation reaction, and bisphenol Converted to A.
The reaction product liquid obtained in the recombination device 6 is supplied to the lines 31 and 1
5 and circulated to the condensation reactor 1. Recombination device 6
A strongly acidic ion exchange resin is used as a catalyst to be charged into the resin. This resin can also be used after being partially modified with a sulfur-containing compound. The reaction temperature of the recombination device 6 is 45 to 120C, preferably 50 to 85C. The reaction pressure is from 1 to 1.5 atm, preferably from normal pressure to slight pressure. The reaction time is 5-200 minutes, preferably 15-
120 minutes.

In the present invention, the water content of the reaction product in the recombination device 6 is kept at 0.1% by weight or less, preferably 0.06% by weight or less. According to the study of the present inventors, when the supply liquid containing the decomposition product liquid obtained in the decomposition apparatus 5 is brought into contact with the strongly acidic ion exchange resin catalyst in the recombination apparatus 6, the water concentration in the supply liquid is reduced. It has been found that the lower the value, the more easily the catalyst poison component present in the feed solution is adsorbed on the resin. According to the present invention, the catalyst poison component is adsorbed and removed by the strongly acidic ion exchange resin catalyst in the recombination device, whereby the catalyst poison component entrained in the bisphenol A circulated from the recombination device to the condensation reactor 1 is removed. This is to reduce the amount, prevent catalyst poisoning in the condensation reactor 1, and maintain stable catalytic activity for a long time. The condensation reactor 1 is a much larger device than the recombination unit 6, and it is not preferable that the activation of the catalyst in the condensation reactor 1 deteriorate. In the case of the present invention, the recombination device 6 functions as a guard reactor for the condensation reaction device 1.

The water in the reaction product liquid of the recombination device 6 is reduced to 0.
As a method for reducing the content to 1% by weight or less, as shown in FIG. 1, a distillation column 4 is disposed upstream of a decomposition device 5, and a mother liquor is distilled in the distillation column 4 so that bisphenol A and its A method of introducing only the bottom fraction in which the isomers are concentrated into the cracker 5 can be shown. When only the bottom fraction of the distillation column 4 is introduced into the decomposer 5 for decomposition treatment, the amount of the raw material to be treated introduced into the decomposer 5 is reduced, so that the supply of the aqueous solution of the alkaline substance is inevitable. A small amount is required, and as a result, the amount of water introduced into the recombination device 6 is also reduced.

In the aqueous solution of the alkaline substance introduced into the distillation column 4, water is distilled off as a column fraction of the distillation column 4 and condensed in the condenser 7. Therefore, by separating a part of the condensate of the condensate 7 to the outside, the amount of water introduced into the recombination device 6 can be reduced.

[0015]

Next, the present invention will be described in more detail with reference to examples.

Example 1 Bisphenol A was produced according to the flow sheet shown in FIG. The main operating conditions at that time are shown below. (1) Condensation reactor 1 (i) Reaction concentration: 70 ° C. (ii) Phenol / acetone molar ratio: 13 (iii) Catalyst: 10% of sulfonic acid groups of sulfonic acid type cation exchange resin are modified with 2-mercaptoethylamine (2) Distillation tower 2 (i) Column fraction composition passing through line 14 Acetone: 97.6 wt% Water: 1.0 wt% Others: 1.4 wt% (ii) Top fraction composition passing through line 17 Phenol: 99.5 wt% Other: 0.5 wt% (iii) Wastewater passing through line 18: 99.95 wt% Phenol: 0.05 wt% (iv) Composition of bottom fraction passing through line 19 Bisphenol A: 22 wt% Phenol A: 74 wt% Other: 4 wt% (3) Crystallizer 3 (i) Mother liquor composition Bisphenol A: 7.7 wt% Bisphenol A isomer: 2.4 wt% Phenol: 86.3wt% Other: 3.6wt%

(4) Distillation column (i) Column fraction composition Phenol: 99.8 wt% Water: 0.05 wt% Other: 0.15 wt% (ii) Column fraction composition Bisphenol A: 48.5 wt% Bisphenol Isomer: 14.8 wt% Phenol: 14.8 wt% Alkaline substance: 0.05 wt% (NaOH) Others: 21.85 wt% (iii) Alkaline catalyst (line 24) 25 wt% aqueous solution of NaOH (5) Decomposer 5 ( i) Reaction temperature: 250 ° C. (ii) Pressure: 40 torr (iii) Decomposition composition (line 27) Phenol: 54 wt% Isopropenyl phenol: 28 wt% Others: 18 wt% (6) Recombination device 6 (i) Reaction temperature : 55 ° C (ii) Catalyst: sulfonic acid type cation exchange resin (iii) Feed composition (line 30) Phenol: 92 6 wt% isopropenyl phenol: 4.4 wt% Water content: 0.04 wt% Others: 2.96 wt% (iv) Reaction product liquid composition Phenol: 89.5 wt% Bisphenol A: 8.0 wt% Water content: 0.04 wt% Others: 2.46wt%

Using phenol and acetone as raw materials,
When a production experiment of bisphenol A was carried out under the above conditions according to the flow sheet of FIG. 1, the conversion of acetone at 2000 hours after the start of the reaction decreased from 92% of acetone at the beginning of the reaction to only 90%. Was.

Comparative Example 1 The procedure was carried out except that a 2 wt% aqueous solution of NaOH supplied to the distillation column 4 was used, and the water concentration in the liquid supplied to the recombination device 6 (line 30) was increased to 0.5 wt%. An experiment was performed in the same manner as in Example 1. As a result, the conversion of acetone at 2000 hours after the start of the reaction was greatly reduced from 92% of acetone at the beginning of the reaction to 85%.

[0020]

According to the present invention, in the production of bisphenol A, the degradation of the activity of the catalyst in the combined reactor of acetone and phenol constituting the main reactor can be effectively suppressed, and the production cost of bisphenol A can be reduced. Can be reduced.

[Brief description of the drawings]

FIG. 1 shows an example of a flow sheet for carrying out the method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Condensation reaction apparatus 2 Distillation tower 3 Crystallizer 4 Distillation tower 5 Decomposition apparatus 6 Recombination apparatus 7 Condenser

──────────────────────────────────────────────────の Continued on front page (51) Int.Cl. ⁶ Identification code FI C07C 37/20 C07C 37/20 37/50 37/50 37/84 37/84 39/16 39/16 39/19 39/19 (72) Inventor Sachio Asaoka 2-1-1, Tsurumichuo, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture Inside Chiyoda Kako Construction Co., Ltd. (72) Inventor Koji Sakashita 2-1-1, Tsurumichuo, Tsurumi-ku, Yokohama-shi, Kanagawa

Claims (1)

[Claims] (1) a bisphenol A producing step in which acetone and an excess amount of phenol are subjected to a condensation reaction in the presence of a strongly acidic ion exchange resin catalyst partially modified with a sulfur-containing amine compound, and (ii) the bisphenol A A crystallization step of cooling a reaction product comprising bisphenol A and phenol obtained in the step A for producing a bisphenol A / phenol crystal adduct and a mother liquor, and (iii) subjecting the obtained mother liquor to the presence of an alkaline catalyst. A heating step, and a decomposition step of decomposing bisphenol A and its isomers in the mother liquor into phenol and isopropenylphenol; and (iv) contacting the decomposition product liquid obtained in the decomposition step with a strongly acidic ion exchange resin catalyst. And recombines phenol and isopropenylphenol contained in the decomposition product solution to form bisphenol A. And (v) circulating the obtained recombination product liquid to the bisphenol A production step, wherein the water content in the reaction product liquid in the recombination step is controlled to 0.1% by weight or less. A method for producing bisphenol A.