JP3834837B2 - Method for producing bisphenol A - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a method for producing bisphenol A.
[0002]
[Prior art]
To produce bisphenol A [2,2-bis (4'-hydroxyphenyl) propane], it is known to react acetone with excess phenol in the presence of a catalyst. In this case, a sulfonic acid type cation exchange resin (unmodified resin) is used as the catalyst. However, when this is used as a catalyst, 2- (2'-hydroxyphenyl) -2- (4'-hydroxyphenyl) -propane (hereinafter simply referred to as 2,4'-bisphenol), which is an isomer of bisphenol A, is used. A) is a by-product of a considerable amount, so that the selectivity of bisphenol A is lowered. Therefore, in order to solve this problem, a modified sulfonic acid type cation exchange group modified with a sulfur-containing amine compound (hereinafter also simply referred to as a modified sulfonic acid group) and an unmodified sulfonic acid type cation exchange group (hereinafter simply referred to as an unmodified sulfonic acid type cation exchange group). It has been proposed to use a modified resin containing both of them (also referred to as a modified sulfonic acid group) (Japanese Patent Laid-Open No. 61-118407, Japanese Patent Publication No. 55-16700, Japanese Patent Publication No. 3-36576).
By the way, when manufacturing bisphenol A using the catalyst which consists of such a modified resin, the catalyst performance falls gradually with use time, and after using for a certain period, it is necessary to replace | exchange for a new catalyst. .
However, such catalyst replacement requires a lot of labor and is also economically disadvantageous. Accordingly, there is a demand for the development of a method for preventing the catalyst performance from being degraded and a method for regenerating the degraded catalyst to a high-performance catalyst again.
[0003]
[Problems to be solved by the invention]
The present invention relates to bisphenol A by reacting acetone and phenol using a catalyst comprising a modified resin containing both a modified sulfonic acid type cation exchange group modified with a sulfur-containing amine compound and an unmodified sulfonic acid type cation group. a method of producing, to provide a way to prevent the deterioration of the catalyst performance and its challenges.
[0004]
[Means for Solving the Problems]
As a result of intensive studies to solve the above problems, the present inventors have found that the problems can be solved by adding a small amount of a thiol compound to the reaction system, and have completed the present invention.
That is, according to the present invention, acetone and phenol are converted using a catalyst comprising a modified resin containing both a modified sulfonic acid type cation exchange group modified with a sulfur-containing amine compound and an unmodified sulfonic acid type cation exchange group. In the method for producing bisphenol A by reacting, a method for producing bisphenol A, characterized in that an alkyl mercaptan is added to the reaction system such that the ratio in the raw material mixture used for the reaction is 3 to 100 ppm by weight. Provided.
[0005]
The sulfonic acid type cation exchange resin used in the present invention is well known in the art, and a gel type or porous type can be used, but a gel type is preferably used. The degree of cross-linking is usually 2-16%, preferably 2-6%. Moreover, the average particle diameter is 0.2-2 mm normally, Preferably it is 0.4-1.5 mm. Such unmodified sulfonic acid type cation exchange resins are already on the market, and for example, Amberlite manufactured by Rohm and Haas, Amberlyst, Dayaion manufactured by Mitsubishi Kasei can be preferably used.
[0006]
The sulfur-containing amine compound used for the modification of the sulfonic acid type cation exchange resin in the present invention is also a well-known compound such as mercaptoalkylpyridine such as 3-mercaptomethylpyridine, 3-mercaptoethylpyridine, 4-mercaptoethylpyridine and the like. Mercaptoalkylamine (or aminoalkyl mercaptan) such as 2-mercaptoethylamine, 3-mercaptobutylamine, 3-n-propylamino-1-propylmercaptan; thiazolidine, 2,2-dimethylthiazolidine, cycloalkylthiazolidine, 2-methyl And thiazolidine such as 2-phenylthiazolidine and 3-methylthiazolidine; and aminothiophenol such as 1,4-aminothiophenol. Particularly preferred are 2-mercaptoethylamine and 2,2-dimethylthiazolidine. The aforementioned sulfur-containing amine compound can be an addition salt of an acidic substance such as hydrochloric acid or a quaternary ammonium salt.
[0007]
Modification of the sulfonic acid type cation exchange resin can be performed by reacting the resin with a sulfur-containing amine compound in water or an organic solvent. As the organic solvent, phenol or acetone can be used, but it is preferably carried out in water. As the reaction temperature, room temperature or warming is adopted, and the reaction time is not particularly long and a few minutes is sufficient. In order to make it react uniformly, it is preferable to stir the reaction mixture. In this reaction, a part of the sulfonic acid type cation exchange group (unmodified sulfonic acid group) contained in the unmodified resin, usually 3 to 30%, preferably 5 to 15% is modified sulfonic acid type cation. It is good to carry out so that it may be converted into an ion exchange group (modified sulfonic acid group).
[0008]
The alkyl mercaptans used in the present invention, for example, methyl mercaptan, ethyl mercaptan, n- propyl mercaptan, a etc. n- butyl mercaptan.
[0009]
In order to produce bisphenol A using the modified resin, acetone and phenol are continuously supplied to a reactor filled with the modified resin as a catalyst to circulate the modified resin packed bed, while acetone is added. The reaction product containing bisphenol A is continuously withdrawn from the reactor. The reaction temperature is a temperature equal to or higher than the melting point of phenol, usually 40 to 100 ° C., preferably 50 to 90. The reaction pressure is 1 to 1.5 atmospheres, preferably normal to slight pressure. The reaction time is 15 to 200 minutes, preferably 30 to 120 minutes. The usage-amount of phenol is 8-20 mol with respect to 1 mol of acetone, Preferably it is 10-16 mol.
In the present invention, a thiol compound is added to the reaction system. For this purpose, a method of adding a thiol compound to phenol and / or acetone or a mixture of phenol and acetone as a reaction raw material, In addition to the reaction raw material, a method of directly adding to the reactor can be employed.
[0010]
Next, the present invention will be described with reference to the drawings.
FIG. 1 is an explanatory view of a reactor for producing bisphenol A. In FIG. 1, 1 is a reactor, 2 is a resin packed bed (catalyst packed bed).
[0011]
In order to form the catalyst packed bed in the reactor, first, the unmodified sulfonic acid type cation exchange resin is filled into the reactor 1 for producing bisphenol A to form the unmodified resin packed layer 2. An unmodified resin is usually marketed as a hydrated product. However, such a hydrated unmodified resin is contacted with phenol in advance before contacting with a phenol solution of a sulfur-containing amine compound, and water contained in the resin is contained in the resin. Is preferably substituted with phenol.
Next, with the valve 5 and the valve 6 opened, a phenol solution of a sulfur-containing amine compound is introduced into the bottom of the reactor via the line 3 and further circulated in the unmodified resin packed bed 2 upward. The phenol solution that has flowed through the packed bed 2 is stored in the upper space of the packed bed 2, and excess phenol solution from the upper space volume is withdrawn out of the reactor through the line 4. The concentration of the sulfur-containing amine compound in the phenol solution is usually 0.1 to 10% by weight, preferably 1 to 5% by weight. The total amount of the phenol solution to be circulated in the unmodified resin packed layer 2 is such that 3 to 30% by weight, preferably 5 to 15% by weight of the total unmodified resin amount is converted into the modified resin. The flow rate of the phenol solution through which the unmodified resin packed layer is circulated is 0.01 to 0.20 kg / min, preferably 0.02 to 0.1 kg / min, per 1 kg of the resin based on the dry matter.
After the reaction between the unmodified resin and the sulfur-containing amine compound in the reactor as described above, the valve 5 is opened, and the phenol solution present in the reactor is taken out of the reactor. In this way, the catalyst packed bed 2 made of a modified resin containing both modified sulfonic acid groups and unmodified sulfonic acid groups is formed in the reactor 1. The catalyst packed bed formed in this way has the modified sulfonic acid groups contained therein almost uniformly dispersed, and the difference in the content of the modified sulfonic acid groups in the modified sulfonic acid resin at the bottom and top of the catalyst packed bed. Is usually within 5%.
When a catalyst packed bed made of a modified resin is formed in the reactor 1 as described above, the phenol solution can be circulated downward from the top of the reactor instead of from the bottom.
[0012]
As described above, when a catalyst packed layer made of an unmodified resin is formed in the reactor 1, the sulfur-containing amine compound is preferably used as a phenol solution. When the sulfur-containing amine compound is used as a phenol solution and is circulated through the unmodified resin layer 2, the reaction rate between the sulfur-containing amine compound and the unmodified sulfonic acid group is slow, so that the unmodified sulfonic acid group in the packed bed 2 And the sulfur-containing amine compound are prevented from reacting rapidly, and both reactions can be carried out in a substantially uniform state throughout the unmodified resin layer. When the sulfur-containing compound is circulated in the unmodified resin layer 2 as an aqueous solution, the reaction rate between the sulfur-containing compound and the unmodified sulfonic acid group is high, so that a rapid reaction occurs at the bottom of the unmodified resin layer. The reaction that occurs near the top of the resin layer 2 is small, and the concentration of the modified sulfonic acid group at the bottom of the resin layer is extremely high, while the concentration of the modified sulfonic acid group at the top of the resin layer is extremely small.
[0013]
The reactor having the catalyst packed bed formed as described above is used as a reactor for producing bisphenol A. That is, a mixed liquid of acetone and phenol is introduced into the reactor 1 from the line 4, and a thiol compound is added to the mixture via the line 7 and the valve 8, and the mixed liquid containing the thiol compound is added to the catalyst packed bed 2. Circulate. During this time, the reaction between acetone and phenol occurs, and the reaction organism containing bisphenol A is withdrawn from the reactor 1 through the line 3.
[0014]
The thiol compound supplied to the reaction system through the line 7 may be used alone or may be a phenol solution, an acetone solution, or a solution dissolved in a mixed solution of phenol and acetone. The amount of the thiol compound added is such that the concentration of the thiol compound in the raw material mixture is 0.3 to 1000 ppm by weight, preferably 3 to 100 ppm by weight.
By carrying out the reaction as described above, it is possible to prevent a decrease in catalyst performance, and it is possible to continuously produce bisphenol A with a high yield and good selectivity over 10,000 hours or more.
[0015]
The addition of the thiol compound to the reaction system need not be performed continuously from the beginning of the reaction as described above, and can be performed intermittently .
[0016]
According to the study by the present inventors, it has been found that the decrease in the catalyst performance is caused by the functional cessation of the modified sulfonic acid group in the catalyst due to poisoning. The principle of preventing the deterioration of the catalyst performance of the present invention, in the coexistence of the thiol compound to the reaction system, Ru near preventing poisoning of modified sulfonic acid group.
[0017]
【Example】
Next, the present invention will be described in more detail with reference to examples.
[0018]
Reference example 1
The catalyst for the reactor for producing bisphenol A was filled using the reactor shown in FIG. In this case, the reactor 1 was a cylindrical vessel having an inner diameter of 120 mm and a height of 1.5 m, and a perforated plate (pore diameter: about 0.1 mm) provided at the top of the reactor.
[0019]
First, an unmodified sulfonic acid type cation exchange resin (average particle diameter: 0.5 mm, trade name “Amberlite 118-H, which has a moisture content of 65 wt%) in a wet state by absorbing water into the reactor 1. , Manufactured by Rohm & Haas Co., Ltd.) to form an unmodified resin packed layer 2. Next, the valve 5 and the valve 6 are opened, and phenol is circulated through the line 3, and is extracted from the line 4 to the outside of the reactor. While the unmodified resin was brought into contact with phenol, the water in the resin was replaced with phenol.
Next, a 3 wt% phenol solution of 2-mercaptoethylamine (MEA) was added to the reactor 1 having the unmodified resin packed layer formed in this way via the line 3 and the valve 5 in the entire resin packed layer. While introducing 1.3 times the weight (on a dry matter basis), the unmodified resin layer 2 was circulated upward. In this case, the contact temperature between the resin and the phenol solution is 70 ° C., and the circulation amount of the phenol solution that has passed through the resin-filled layer is 6 times the weight of the resin-filled layer (on a dry matter basis). The feed rate to the layer is 0.05 kg / min per kg of resin on a dry matter basis.
After supplying the phenol solution to the resin packed layer as described above, the phenol solution in the reactor was removed to the outside of the reactor. When the distribution of the modified sulfonic acid group content in the resin-filled layer thus formed was examined, the modified group content in the modified resin at the top of the resin-filled layer was about 9.8%, The modified sulfonic acid group content in the modified resin at the bottom was about 10.2%, and it was confirmed that the modified sulfonic acid groups were distributed almost uniformly throughout the resin layer.
[0020]
Reference example 2
In Reference Example 1, an experiment was conducted in the same manner except that a phenol solution of 2,2-dimethylthiazolidine (DMT) was used instead of the MEA phenol solution. Also in this case, the distribution of the modified sulfonic acid groups in the obtained catalyst packed bed was almost uniform.
[0021]
Example 1
Reactor acetone (manufactured by Wako Pure Chemical Industries, special grade) 4.7% by weight and reagent phenol (manufactured by Wako Pure Chemical Industries, Ltd.) with respect to the reactor 1 in which the catalyst packed layer 2 was formed inside obtained in Reference Example 1. The reagent mixture of 95.3% by weight is introduced into the reactor 1 through the line 4, and ethyl mercaptan as a thiol compound is added to the mixture through the line 4 through the line 7 and the valve 8. Mixed. In this case, the amount of the thiol compound added was 30 ppm by weight as the concentration in the reaction mixture before passing through the catalyst packed bed 2. The reaction product liquid was withdrawn from the reactor 1 via the line 3. In this case, the reaction temperature was 70 ° C., and the contact time between the catalyst and the mixed solution was 70 minutes.
As a result of analyzing the reaction product of 500 hours obtained by continuous reaction as described above, the production rate of bisphenol A is 7.00 mol%, and its isomer, 2,4′-bisphenol. The production rate of A was 0.28%.
As a result of continuous reaction for 3000 hours as described above, the reaction product solution had a production rate of bisphenol A of 6.95 mol%, and the production rate of 2,4′-bisphenol A, which is an isomer thereof, was It was 0.28 mol%, and it was confirmed that the catalyst performance was maintained at a high performance for a long time.
[0022]
Comparative Example 1
In Example 1, the experiment was performed in the same manner except that the thiol compound was not added. In this case, the product composition at 500 hours was almost the same as that of Example 1, but the reaction product composition at 3000 hours was 4.88 mol% of bisphenol A, and The production rate of 2,4′-bisphenol A, which is the isomer, was 0.37 mol%, and it was confirmed that the catalyst performance was lowered.
[0023]
Example 2
In Example 1, the reaction between acetone and phenol was carried out in the same manner except that the reactor obtained in Reference Example 2 was used as the reactor 1 in which a catalyst packed layer was formed.
As a result of analyzing the reaction product at 500 hours obtained by continuous reaction as described above, the production rate of bisphenol A was 7.04 mol%, and its isomer 2,4′-bisphenol. The production rate of A was 0.29 mol%.
When the reaction was carried out continuously for 3000 hours, the reaction product composition was 7.03 mol% of bisphenol A, and 2,4′-bisphenol A, which is an isomer, was produced. The catalyst performance was confirmed to be maintained at high performance for a long time.
[0024]
Comparative Example 2
In Example 2, an experiment was performed in the same manner except that no thiol compound was added. In this case, the product composition at 500 hours was almost the same as in Example 2, but the reaction product composition at 3000 hours had a production rate of bisphenol A of 4.95 mol%, The production rate of 2,4′-bisphenol A, which is the isomer, was 0.39 mol%, and it was confirmed that the catalyst performance was lowered.
[0027]
【The invention's effect】
According to the present invention, in the production of bisphenol A, the catalyst performance can be maintained at high performance for a long time, whereby bisphenol A can be produced in high yield and high selectivity.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a reactor.
[Explanation of symbols]
1 reactor 2 resin packed bed (catalyst packed bed)
5, 6, 8 valves

Claims (4)

Bisphenol A is produced by reacting acetone and phenol using a catalyst comprising a modified resin containing both a modified sulfonic acid type cation exchange group modified with a sulfur-containing amine compound and an unmodified sulfonic acid type cation exchange group. In the method, a method for producing bisphenol A, comprising adding an alkyl mercaptan to a reaction system so that a ratio in a raw material mixture to be subjected to the reaction is 3 to 100 ppm by weight . Bisphenol A is produced by reacting acetone with phenol using a catalyst comprising a modified resin containing both a modified sulfonic acid type cation exchange group modified with a sulfur-containing amine compound and an unmodified sulfonic acid type cation exchange group. In the method, the catalyst is exchanged or regenerated for at least 3000 hours while adding alkyl mercaptans to the reaction system so that the ratio in the raw material mixture used for the reaction is 3 to 100 ppm by weight, while suppressing the decrease in catalyst activity. A process for producing bisphenol A, characterized in that the reaction is continued without performing. 3. The process for producing bisphenol A according to claim 2, wherein the reaction is continued for at least 10,000 hours without exchanging or regenerating the catalyst. The method for producing bisphenol A according to any one of claims 1 to 3, wherein the catalyst is obtained by modifying 5 to 15% of a sulfonic acid type cation exchange group with a sulfur-containing amine compound.

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