Title of Invention

CATALYST FOR BISPHENOL PRODUCTION

Abstract

To provide a catalyst for producing bisphenols that can be prepared with a simple operation using a sulfur-containing amine compound that is contained in wastewater discharged from a bisphenols production process and must be removed; and a method for producing bisphenols using the catalyst. A catalyst for producing bisphenols comprising an acidic cation exchange resin on which the sulfur-containing amine compound contained in wastewater discharged from the bisphenol production process is adsorbed; and a method of producing bisphenols using the catalyst are provided.

Full Text

DESCRIPTION CATALYST FOR PRODUCING BISPHENOLS Technical Field [0001] The present invention relates to a catalyst for producing bisphenols and a method for producing bisphenols using the catalyst. More particularly, the invention relates to a catalyst for producing bisphenols comprising an acidic cation exchange resin on which a sulfur-containing amine compound contained in wastewater discharged from a bisphenol production process is adsorbed; and a method for producing bisphenols using the catalyst. Background Art [0002] Bisphenols are known to be important compounds as raw materials for polymers and the like. Particularly, bisphenol A, a representative compound of bisphenols, is used as a raw material for engineering plastics such as polycarbonate resins and polyarylate resins, epoxy resins, or the like. In recent years, a demand for bisphenol A has tended to increase. It is publicly known that such bisphenols including bisphenol A are produced by a reaction between a phenol and a carbonyl compound using a fixed bed of an acidic cation exchange resin as a catalyst. It is also known that, in this reaction, a catalyst in which a sulfur-containing amine compound is adsorbed on the above-mentioned acidic cation exchange resin is used to prevent production of byproducts such as, in the case of bisphenol A, 2-(2-hydroxyphenyl)-2-(4-hydroxyphenyl)propane, which is an isomer thereof. [0003] When the catalyst is prepared in an apparatus for producing bisphenols, that is to say, when a sulfur-containing amine compound is adsorbed on an acidic cation exchange resin, wastewater containing the sulfur-containing amine compound is discharged. Further, leakage of the sulfur-containing amine compound may occur during preparation of the catalyst. It is difficult to treat such wastewater containing a sulfur-containing amine compound discharged from a bisphenol production apparatus with activated sludge due to a low BOD value of the sulfur-containing amine compound contained therein. There may be adopted a method in which the wastewater is not sent to a facility for treating wastewater with activated sludge but subjected to liquid incineration in an incinerator, but this method requires high capital investment and also a large amount of fuel to incinerate organic substances in water. Accordingly, it is desired to remove a sulfur-containing amine compound from wastewater containing the sulfur-containing amine compound with simple means. As a method for treating wastewater containing amines, there is disclosed a method comprising a step of contacting wastewater containing water-soluble amines with a weakly acidic ion exchange resin, a step of regenerating the weakly acidic ion exchange resin on which the amines are adsorbed with an inorganic acid, and a step of neutralizing the regeneration solution with an alkali (See, for example, Patent Document 1). This method, however, has a problem that the operation is complicated since it comprises three steps including a regerenation step. [0004] Patent Document 1: Japanese Patent Application Laid-Open (JP-A) No. S58-30387 Disclosure of the Invention Problems to be Solved by the Invention [0005] The present invention has been accomplished under such circumstance and has as an object to provide a catalyst for producing bisphenols that can be prepared with a simple operation using a sulfur-containing amine compound that is contained in wastewater discharged from a bisphenol production process and must be removed; and a method for producing bisphenols using the catalyst. Means to Solve the Problems [0006] The present inventors found, as a result of keen examination, that the above object can be achieved by adsorbing a sulfur-containing amine compound contained in wastewater discharged from a bisphenol production process on an acidic cation exchange resin. The present invention has been completed based on these findings. [0007] The present invention thus provides: (1) A catalyst for producing bisphenols comprising an acidic cation exchange resin on which a sulfur-containing amine compound contained in wastewater discharged from a bisphenol production process is adsorbed; (2) The catalyst for producing bisphenols according to item (1) above, wherein the wastewater discharged from a bisphenol production process is wastewater discharged from a catalyst preparation step; (3) A catalyst for producing bisphenols comprising a catalyst comprising an acidic cation exchange resin on which a sulfur-containing amine compound prepared in a catalyst preparation step is adsorbed and the catalyst according to item (1) above; (4) A catalyst for producing bisphenols comprising a catalyst comprising an acidic cation exchange resin on which a sulfur-containing amine compound prepared in a catalyst preparation step is adsorbed and the catalyst according to item (2) above; (5) The catalyst for producing bisphenols according to item (1) above, wherein the acidic cation exchange resin is a gel-form strongly acidic cation exchange resin; (6) The catalyst for producing bisphenols according to item (2) above, wherein the acidic cation exchange resin is a gel-form strongly acidic cation exchange resin; (7) The catalyst for producing bisphenols according to item (3) above, wherein the acidic cation exchange resin is a gel-form strongly acidic cation exchange resin; (8) The catalyst for producing bisphenols according to item (4) above, wherein the acidic cation exchange resin is a gel-form strongly acidic cation exchange resin; (9) The catalyst for producing bisphenols according to item (5) above, wherein the gel-form strongly acidic cation exchange resin has a degree of crosslinking of 2 to 8%; (10) The catalyst for producing bisphenols according to item (6) above, wherein the gel-form strongly acidic cation exchange resin has a degree of crosslinking of 2 to 8%; (11) The catalyst for producing bisphenols according to item (7) above, wherein the gel-form strongly acidic cation exchange resin has a degree of crosslinking of 2 to 8%; (12) The catalyst for producing bisphenols according to item (8) above, wherein the gel-form strongly acidic cation exchange resin has a degree of crosslinking of 2 to 8%; (13) The catalyst for producing bisphenols according to any of items (1) to (12) above, wherein the bisphenol is 2,2-bis(4-hydroxyphenyl)propane, that is, bisphenol A; (14) A method for producing bisphenols wherein the catalyst according to any of items (1) to (12) above is used; and (15) A method for producing bisphenols wherein the catalyst according to item (13) above is used. Effects of the Invention [0008] According to the present invention, a catalyst for producing bisphenols that can be prepared with a simple operation using a sulfur-containing amine compound contained in wastewater discharged from a bisphenol production process and must be removed; and a method for producing bisphenols using the catalyst can be provided. In addition, the wastewater containing the sulfur-containing amine compound discharged after preparation of the catalyst for producing bisphenols according to the present invention can be sent as it is to a wastewater treatment facility. Best Mode for Carrying Out the Invention [0009] Bisphenols to which the catalyst for producing bisphenols according to the present invention is applicable are produced by condensation of a phenol and a carbonyl compound. Examples of the phenols include those with no substituents at the para position to the hydroxyl group, for example, phenol; alkylphenols such as o-cresol, m-cresol, o-tert-butylphenol, 2,6-xylenol, 2,6-di-tert-butyIphenol; and halogenated phenols such as o-chlorophenol, m-chlorophenol, and 2,6-dichlorophenol. While examples of the carbonyl compounds include ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl n-propyl ketone, acetophenone, and cyclohexanone; and aldehydes such as formaldehyde, acetaldehyde, and benzaldehyde. Especially, the catalyst according to the present invention is suitably applied for producing bisphenol A, which is obtained by condensation of phenol and acetone. [0010] The acidic cation exchange resin used in the present invention is preferably a sulfonic acid-type cation exchange resin, which is a strongly acidic cation exchange resin. The matrix resin thereof includes styrene-divinylbenzene copolymer resins, perfluoroethylene-based copolymer resins, phenol-formaldehyde polymer resins, and the like, among which styrene-divinylbenzene copolymer resins are preferable. These resins may be used both in a gel form and a porous form, but a gel form is more preferable. The resins with a relatively low degree of crosslinking, for example, 2 to 8%, are preferable. [0011] According to the present invention, a fixed bed is formed by filling the acidic cation exchange resin into a reactor. Then, an aqueous solution of a sulfur-containing amine compound, which is wastewater discharged from a bisphenol production process, is injected into the fixed bed reactor, thereby adsorbing the sulfur-containing amine compound contained in the aqueous solution on the acidic cation exchange resin to modify the resin. Thus, a catalyst for producing bisphenols (also simply referred to as "catalyst" hereinafter) is prepared. Examples of the sulfur-containing amine compound include, for example mercaptopyridines such as 3-mercaptopyridine; mercaptoalkylamines such as 2-mercaptoethylamine; thiazolidines such as 2,2-dimethylthiazolidine; aminothiophenols such as 4-aminothiophenol; and pyridinealkanethiols such as 4-pyridineethanethiol. Among these, 4-pyridineethanethiol, 2,2-dimethylthiazolidine, and 2-mercaptoethylamine are preferable. According to the present invention, the wastewater may contain only one kind or two or more kinds of these sulfur-containing amine compounds. [0012] There are no particular limitations on the method by which the catalyst is prepared by contacting an aqueous solution of a sulfur-containing amine compound with an acidic cation exchange resin to adsorb the sulfur-containing amine compound contained therein to the acidic cation exchange resin to modify the resin. Although this procedure may be performed, for example, in the batch mode, the catalyst is usually prepared in a reactor prior to a reaction, exemplified by the following methods: (1) An acidic cation exchange resin is filled in a reactor and an aqueous solution of a sulfur-containing amine compound is simply injected from the upper part; (2) An acidic cation exchange resin is filled in a reactor and an aqueous solution of a sulfur-containing amine compound is injected from the upper part while a part of the aqueous solution discharged is circulated; (3) An acidic cation exchange resin is filled in a reactor and air bubbles are flown through the reactor from the lower part thereof while or after an aqueous solution of a sulfur-containing amine compound is injected from the upper part (Japanese Patent Application Laid-Open (JP-A) No. 2000-254523); and (4) After an acidic cation exchange resin is filled in a reactor to form a fixed bed, prior to starting a reaction, the resin is washed with water, and an aqueous solution that is prepared by dissolving a sulfur-containing amine compound in the washing water discharged is injected and circulated (Japanese Patent Application Laid-Open (JP-A) No. 2001-286770). The amount of the acidic cation exchange resin to be filled may be selected as appropriate depending on the concentration of the sulfur-containing amine compound in the wastewater to be flown through, the volume of the wastewater to be flown through, and the type and concentration of an acid contained in the wastewater. [0013] Moreover the catalyst preparation may be performed at an ordinary temperature or with warming, if required. In the treatment for preparing the catalyst, a sulfonic acid group, which is an ion-exchanging group, reacts with an amino group in the sulfur-containing amine compound, a sulfur-containing group is introduced into a part of the ion-exchanging group, and thus the resin is modified at a desired modification rate (5 to 50%, preferably 8 to 30%). The term "modification rate" refers to a molar conversion rate of the sulfonic acid group in the acidic cation exchange resin with a sulfur-containing amine compound. One aspect of the present invention is a catalyst prepared by injecting wastewater containing a sulfur-containing amine compound discharged or leaked upon preparing the catalyst as described above into a fixed bed comprising an acidic cation exchange resin by the above method to adsorb the sulfur-containing amine compound on the acidic cation exchange resin. As the catalyst for producing bisphenols in the present invention, the catalyst comprising an acidic cation exchange resin on which a sulfur-containing compound contained in wastewater is adsorbed by the above procedures may be used alone or in combination with a catalyst comprising an acidic cation exchange resin on which a sulfur-containing amine compound prepared in a catalyst preparation step is adsorbed. [0014] The second invention of the present application is a method for producing bisphenols characterized by using the catalyst described above. As a representative example, the method for producing bisphenol A will be described. For the condensation reaction between phenol and acetone, one may employ a fixed-bed continuous reaction system in which phenol and acetone are fed continuously to a reactor filled with the above-described catalyst to allow them to react. In this system, one reactor may be used, or two or more reactors may be installed in a serial or a parallel arrangement. Industrially, it is particularly advantageous to adopt a fixed-bed multi-step continuous reaction system wherein two or more reactors filled with the catalyst are serially connected. [0015] The reaction conditions for this fixed-bed continuous reaction system will be described. Firstly the acetone/phenol molar ratio is selected usually in the range from 1/30 to 1/3, preferably from 1/20 to 1/5. If the ratio is less than 1/30, the reaction rate may be too slow, while if the ratio exceeds 1/3, generation of impurities tend to increase lowering the selectivity for bisphenol A. Then the reaction temperature is selected usually in the range from 40 to 150°C, preferably from 55 to 100°C. If the temperature is lower than 40°C, the reaction rate is slow and the reaction mixture has a very high viscosity and may sometimes be solidified. If the temperature exceeds 150°C, the reaction is difficult to control, the selectivity for bisphenol A decreases, and the ion exchange resin used as the catalyst may be decomposed or degraded. Moreover the liquid hourly space velocity (LHSV) of the raw material mixture is selected usually in the range from 0.2 to 30 hr-1, preferably from 0.5 to 20 hr-1. [0016] In the method of the present invention, the reaction mixture discharged from a reactor may be subjected to post-treatment by a publicly known method to isolate bisphenol A. One example of the post-treatment will be described below. First, the reaction mixture is concentrated prior to crystallization. The conditions in concentration are not particularly limited; the concentration is usually performed under conditions of a temperature of 130 to 170°C and a pressure of 13 to 53 kPa. If the temperature is lower than 130°C, high vacuum is required. If the temperature exceeds 170°C, impurities may increase and coloration may be caused. The concentration of bisphenol A in the concentrated residual solution is advantageously in the range from 25 to 40 mass%. If the concentration is lower than 25 mass%, the recovery rate of bisphenol A is low, while if the concentration exceeds 40 mass%, transfer of a slurry after crystallization may be difficult. [0017] Crystallization of an adduct of bisphenol A with phenol from the concentrated residual solution is usually performed by vacuum cooling crystallization in which a solution is cooled by using evaporation latent heat of water under reduced pressure. In the vacuum cooling crystallization, approximately 3 to 20 mass% of water is added to the concentrated residual solution and the crystallization is performed under conditions of a temperature of 40 to 70°C and a pressure of 3 to 13 kPa. If the above amount of water added is lower than 3 mass%, heat removal ability is insufficient, while if the amount exceeds 20 mass%, dissolution loss of bisphenol A is large; these conditions are not preferable. If the crystallization temperature is lower than 40°C, the crystallization solution may have increased viscosity or may be solidified, while if the temperature exceeds 70°C, dissolution loss of bisphenol A increases; these conditions are not preferable. [0018] Next, after the adduct of bisphenol A with phenol thus crystallized is separated by a publicly known method, the adduct is usually subjected to washing treatment with phenol. Then, the adduct after the washing is treated to separate into bisphenol A and phenol. In the separation, the temperature is selected usually in the range from 130 to 200°C, preferably from 150 to 180°C, and the pressure is selected usually in the range from 3 to 20 kPa. Phenol remaining in bisphenol A obtained by this separation treatment is removed substantially completely by a method such as steam stripping to obtain bisphenol A with high quality. Examples [0019] The present invention will be illustrated in more detail referring to Examples and Comparative Examples, but the present invention is not limited by these Examples. [0020] Reference Example 1 A glass column with an inner diameter of 25 mm and a length of 20 cm was filled with 50 cm3 of a sulfonic acid-type cation exchange resin (DIAION SK-104, Mitsubishi Chemical Corporation) swollen with water. A circulatory line and a feed line of 2,2-dimethylthiazolidine (also referred to as DMT hereinafter) were set. A solution containing 170 mass ppm of DMT and 0.4 mass% of phosphoric acid was circulated in the circulatory line at 200 mL/h. In order to maintain the concentration of DMT at 170 mass ppm, a solution containing 1.3 mass% of DMT was fed to the circulatory line at 2.6 mL/h. When modification of 50 cm of the catalyst was completed, 230 mL of wastewater had been generated and the concentration of DMT was 170 mass ppm and the concentration of phosphoric acid was 0.4 mass% at the column outlet. Totally 30 glass columns were used to treat 1,500 cm3 of the cation exchange resin. At this time, 7,000 mL of wastewater was generated, the concentration of DMT in the wastewater was 170 mass ppm, and the concentration of phosphoric acid was 0.4 mass%. The modification rate of the cation was 23%. One of the glass columns was used to evaluate reaction performance. Under the conditions of the reaction temperature of 75°C, phenol/acetone (molar ratio) = 10/1, and LHSV = 6 h-1, the conversion rate of phenol was 12.1% and the selectivity for bisphenol A was 93.5%. [0021] Example 1 A glass column with an inner diameter of 25 mm and a length of 20 cm was filled with 50 cm3 of a sulfonic acid cation exchange resin (DIAION SK-104, Mitsubishi Chemical Corporation) swollen with water. To the column, the wastewater generated in Reference Example 1 containing 170 mass ppm of DMT and 0.4 mass% of phosphoric acid was injected at 400 mL/h. A total of 7,000 mL of the wastewater was injected. The concentration of DMT was measured periodically at the outlet. The concentration of DMT could be maintained at 5 mass ppm or lower and the concentration of phosphoric acid at 0.4 mass% until the end of treatment. The modification rate of the cation was 16%. The reaction performance of the catalyst examined under the same conditions as those for Reference Example 1 were almost the same as those for Reference Example 1. Industrial Applicability [0022] Regarding the catalyst for producing bisphenols and the method for producing bisphenols using the catalyst of the present invention, the catalyst can be prepared with a simple operation using a sulfur-containing amine compound that is contained in wastewater discharged from a bisphenol production process and must be removed. Further, the wastewater containing the sulfur-containing amine compound discharged after preparation of the catalyst for producing bisphenols of the present invention can be sent as it is to a wastewater treatment facility. CLAIMS 1. A catalyst for producing bisphenols comprising an acidic cation exchange resin on which a sulfur-containing amine compound contained in wastewater discharged from a bisphenol production process is adsorbed. 2. The catalyst for producing bisphenols according to Claim 1, wherein the wastewater discharged from a bisphenol production process is wastewater discharged from a catalyst preparation step. 3. A catalyst for producing bisphenols comprising a catalyst comprising an acidic cation exchange resin on which a sulfur-containing amine compound prepared in a catalyst preparation step is adsorbed and the catalyst according to Claim 1. 4. A catalyst for producing bisphenols comprising a catalyst comprising an acidic cation exchange resin on which a sulfur-containing amine compound prepared in a catalyst preparation step is adsorbed and the catalyst according to Claim 2. 5. The catalyst for producing bisphenols according to Claim 1, wherein the acidic cation exchange resin is a gel-form strongly acidic cation exchange resin. 6. The catalyst for producing bisphenols according to Claim 2, wherein the acidic cation exchange resin is a gel-form strongly acidic cation exchange resin. 7. The catalyst for producing bisphenols according to Claim 3, wherein the acidic cation exchange resin is a gel-form strongly acidic cation exchange resin. 8. The catalyst for producing bisphenols according to Claim 4, wherein the acidic cation exchange resin is a gel-form strongly acidic cation exchange resin. 9. The catalyst for producing bisphenols according to Claim 5, wherein the gel-form strongly acidic cation exchange resin has a degree of crosslinking of 2 to 8%. 10. The catalyst for producing bisphenols according to Claim 6, wherein the gel-form strongly acidic cation exchange resin has a degree of crosslinking of 2 to 8%. 11. The catalyst for producing bisphenols according to Claim 7, wherein the gel-form strongly acidic cation exchange resin has a degree of crosslinking of 2 to 8%. 12. The catalyst for producing bisphenols according to Claim 8, wherein the gel-form strongly acidic cation exchange resin has a degree of crosslinking of 2 to 8%. 13. The catalyst for producing bisphenols according to any of Claims 1 to 12, wherein the bisphenol is 2,2-bis(4-hydroxyphenyl)propane, that is, bisphenol A. 14. A method for producing bisphenols wherein the catalyst according to any of Claims 1 to 12 is used. 15. A method for producing bisphenols wherein the catalyst according to Claim 13 is used. Dated this 26 day of October 2006

Documents:

3926-CHENP-2006 AMENDED PAGES OF SPECIFICATION 19-01-2012.pdf

3926-CHENP-2006 AMENDED CLAIMS 15 -11-2012.pdf

3926-CHENP-2006 AMENDED CLAIMS 19-01-2012.pdf

3926-CHENP-2006 CORRESPONDENCE OTHERS 05-11-2012.pdf

3926-CHENP-2006 CORRESPONDENCE OTHERS 07-02-2012.pdf

3926-CHENP-2006 CORRESPONDENCE OTHERS 15 -11-2012.pdf

3926-CHENP-2006 CORRESPONDENCE OTHERS 30-08-2011.pdf

3926-CHENP-2006 ENGLISH TRANSLATION 07-02-2012.pdf

3926-CHENP-2006 EXAMINATION REPORT REPLY RECEIVED 19-01-2012.pdf

3926-CHENP-2006 FORM-3 19-01-2012.pdf

3926-CHENP-2006 OTHER PATENT DOCUMENT 19-01-2012.pdf

3926-CHENP-2006 CORRESPONDENCE OTHERS 27-07-2012.pdf

3926-CHENP-2006 FORM-3 27-07-2012.pdf

3926-chenp-2006-abstract.pdf

3926-chenp-2006-claims.pdf

3926-chenp-2006-correspondnece-others.pdf

3926-chenp-2006-description(complete).pdf

3926-chenp-2006-form 1.pdf

3926-chenp-2006-form 26.pdf

3926-chenp-2006-form 3.pdf

3926-chenp-2006-form 5.pdf

3926-chenp-2006-pct.pdf