Isomerization process for the preparation of bisphenols from the condensation reaction of ketones and phenols

Abstract

The present invention relates to a method for isomerizing a product obtained by the condensation reaction of a ketone and a phenol to prepare a bisphenol, the method comprising contacting the product obtained by the condensation reaction of a ketone and a phenol to prepare a bisphenol with an ion exchange resin under aqueous conditions for isomerization of undesirable products and separation of products with a higher bisphenol content, wherein the ion exchange resin is an aromatic polymer having a sulfonic acid group, and the sulfonic acid group is modified by at least one promoter selected from the compound represented by structure (I):

Description

Technical Field

[0001] The present invention relates to the field of chemistry and, more particularly, to chemical mixtures and chemical processes for preparing ion exchange resins for isomerization of undesirable products obtained from the preparation of bisphenols. Background Art

[0002] As is known to all, bisphenol is a substance obtained by the condensation reaction of phenol and ketone, especially 4,4'-isopropylidenediphenol (4,4'BPA), which is the main desired bisphenol product used as a precursor in the preparation of polycarbonate. The bisphenol production process comprises the following steps: (1) condensation reaction of acetone and phenol with an acidic compound as a catalyst; (2) dehydration and concentration of the condensation product; (3) cooling the mixture obtained in step (2) and then separating the crystals of 4,4'-isopropylidene diphenol from the mother liquor by filtering to obtain crystals of 4,4'-isopropylidene diphenol product; (4) isomerizing the product obtained from the mother liquor after filtering in step (3) into 4,4'-isopropylidene diphenol by contacting the mother liquor after filtering in step (3) with an ion exchange resin containing an aromatic polymer having sulfonic acid groups that can be modified with a promoter; (5) returning the liquid mixture in the isomerization process of step (4) to step (2) to separate 4,4'-isopropylidene diphenol; (6) separation of phenol and bisphenol mixture to return to the system for use, and separation of tar produced by side reactions in the process from the system; and (7) solidification and drying of the liquid 4,4'-isopropylidene diphenol product.

[0003] Generally, the products obtained from the production of bisphenol contain a variety of compounds, especially 2,4'-isopropylidene diphenol, which is the main product of the condensation reaction of ketone and phenol. It is reported that with acid as a catalyst and under suitable conditions, an isomerization reaction can occur to produce a bisphenol product in the form of 4,4'-isopropylidene diphenol. The acid used can be an inorganic acid, such as sulfuric acid and hydrochloric acid. Nevertheless, the acid catalyst still has some undesirable characteristics, such as equipment corrosion, a low percentage of the obtained product converted into the main product, and a low selectivity for producing the desired product. There are many reports that ion exchange resins with acidic groups as catalysts or ion exchange resins fixed with thiol promoters (wherein the fixation can be through ionic bonds or chemical bonds) can be used for the isomerization of products obtained from bisphenol production.

[0004] Patent document No. US4590303 discloses the use of an ion exchange resin fixed with a mercaptan compound and the addition of acetone to a reactor during an isomerization reaction. However, although the acetone conversion percentage increases, other products are also formed in large quantities. In addition, there is no report that the increase in the acetone conversion percentage affects the increase in the amount of 4,4'-isopropylidene diphenol product.

[0005] Patent document No. US4825010 discloses the use of an ion exchange resin surface-modified with a mercaptoamine compound containing at least two alkyl mercaptan side chains in an isomerization reaction. It is found that it is capable of isomerizing 2,4'-isopropylidene diphenol and other products without increasing compounds generated by side reactions during isomerization, such as 1,3,3-trimethyl-p-hydro-xyphenol-6-hydroxyindane and 4-methyl-2,4-bis-(4'-hydroxyphenyl)-pentene. However, the patent document does not indicate an increase in the amount of 4,4'-isopropylidene diphenol products.

[0006] Patent document No. US5001281 discloses the use of a perfluoropolymer having a sulfonic acid group in its structure as an isomerization catalyst for producing bisphenol fluorene. It is found that the resulting products such as 2,4'-bisphenol fluorene and 9-fluorenone can be isomerized to 4,4'-bisphenol fluorene. However, there is no report that the use of the catalyst and process in the isomerization reaction can reduce the amount of compounds produced by side reactions.

[0007] Patent document No. US4822923 discloses the use of an ion exchange resin having a sulfonic acid group as a catalyst in an isomerization reaction, and an alkylthiol promoter in the form of a co-feed promoter. It is found that it is able to isomerize 2,4'-isopropylidene diphenol and other products obtained without increasing compounds formed by side reactions during isomerization, such as 1,3,3-trimethyl-p-hydro-xyphenol-6-hydroxyindane and 4-methyl-2,4-bis-(4'-hydroxyphenyl)-pentene. However, the patent document does not indicate the increase in the amount of 4,4'-isopropylidene diphenol products, and the patent has the disadvantage of causing pollution when the promoter is used in industrial applications. Therefore, other further processes are required to separate the promoter from the obtained product.

[0008] There is still a need for the development of bisphenol production processes to reduce the amount of the resulting product, or to have a step that effectively converts the resulting product into a 4,4'-isopropylidene diphenol product and reduces the amount of tar produced during decomposition. The present invention is directed to developing a method for isomerizing the product obtained from the condensation reaction of ketones and phenol to prepare bisphenol, the method using an ion exchange resin, the ion exchange resin comprising an aromatic polymer having sulfonic acid groups, the sulfonic acid groups being modified by a promoter selected from the compounds shown in structure (I). The method for isomerizing the resulting product increases the amount of bisphenol, especially 4,4'-isopropylidene diphenol, and reduces the amount of tar in the production process, thereby improving the ratio of product to precursor.

[0009]

[0010] in,

[0011] X represents a heteroatom; and

[0012] n is an integer between 1 and 4. Summary of the invention

[0013] The present invention relates to a method for isomerizing a product obtained by the condensation reaction of a ketone and a phenol to prepare a bisphenol, the method comprising contacting the product obtained by the condensation reaction of a ketone and a phenol to prepare a bisphenol with an ion exchange resin under aqueous conditions for isomerization of undesirable products and separation of products with a higher bisphenol content, wherein the ion exchange resin is an aromatic polymer having a sulfonic acid group, and the sulfonic acid group is modified by at least one promoter selected from the compound represented by structure (I):

[0014]

[0015] in,

[0016] X represents a heteroatom; and

[0017] n is an integer between 1 and 4. DETAILED DESCRIPTION

[0018] The present invention relates to a process for isomerizing products obtained from the condensation reaction of ketones and phenols to produce bisphenols, using an ion exchange resin comprising an aromatic polymer having sulfonic acid groups modified by a promoter.

[0019] Unless otherwise stated, any aspect described herein is meant to include application to other aspects of the invention as well.

[0020] 1. Definition

[0021] Unless otherwise defined, technical or scientific terms used herein have the same definitions as understood by one of ordinary skill in the art.

[0022] Any tools, equipment, methods or chemicals referred to herein refer to tools, equipment, methods or chemicals commonly operated or used by those skilled in the art, unless otherwise specified that they are tools, equipment, methods or chemicals specific only to the present invention.

[0023] When used in the claims or the specification, the singular noun or singular pronoun "comprising" means "a", and also includes "one or more", "at least one" and "one or more than one".

[0024] All compositions and / or methods and claims disclosed in this application are intended to cover any operation, performance, modification or adjustment of any factor, which does not require experiments that are significantly different from the present invention, and according to ordinary technicians in this field, the same target utility and results as the present embodiment are obtained, although not specifically described in the claims. Therefore, the alternative or similar objects of the present embodiment, including any minor modifications or adjustments that are obvious to those skilled in the art, should be interpreted as still remaining within the spirit, scope and concept of the present invention as shown in the appended claims.

[0025] In this application, the term "about" refers to any number appearing or expressed herein, which may vary or deviate due to any error in the equipment, method or person using the equipment or method, including changes or deviations due to changes in reaction conditions due to uncontrollable factors (such as humidity and temperature).

[0026] Heteroatoms refer to atoms including non-carbon elements, and the atoms include, but are not limited to, tetrals group elements, i.e., silicon, germanium, tin and lead; pniktogens group elements, i.e., nitrogen, phosphorus, arsenic, antimony and bismuth; chalcogens group elements, i.e., oxygen, sulfur, selenium and tellurium; or halogens group elements, i.e., fluorine, chlorine, bromine and iodine.

[0027] In the following, the illustrated embodiments of the present invention are not intended to limit any scope of the present invention.

[0028] The present invention relates to a method for isomerizing a product obtained by the condensation reaction of a ketone and a phenol to prepare bisphenol, the method comprising contacting the product obtained by the condensation reaction of a ketone and a phenol to prepare bisphenol with an ion exchange resin under aqueous conditions for isomerization of undesirable products and separation of products with a higher bisphenol content, wherein the ion exchange resin is an aromatic polymer having a sulfonic acid group, and the sulfonic acid group is modified by at least one promoter selected from the compound represented by structure (I):

[0029]

[0030] in,

[0031] X represents a heteroatom; and

[0032] n is an integer between 1 and 4.

[0033] Preferably, at least one promoter is a compound represented by structure (II) or (III):

[0034]

[0035] More preferably, the promoter is a compound represented by structure (II):

[0036]

[0037] In one aspect, the promoter further comprises an aminoalkyl mercaptan, which can be selected from cysteamine, 2-amino-1-propanethiol, and 3-mercaptopropylamine. Preferably, the aminoalkyl mercaptan is cysteamine.

[0038] Most preferably, the promoter is a mixture of a compound according to structure (II) and cysteamine.

[0039] In one aspect of the present invention, the accelerator comprises aminoalkylthiol in an amount of 10 to 90 mol % of the total accelerator, preferably 30 to 70 mol % of the total accelerator.

[0040] In one aspect of the present invention, the sulfonic acid groups modified by the accelerator account for 10% to 20% of the total sulfonic acid groups.

[0041] In one aspect, the sulfonic acid groups are modified by the promoter via ionic bonds, which can be formed via nitrogen atoms of the promoter and sulfonic acid groups of the aromatic polymer.

[0042] Typically, the modification can be carried out by mixing the aromatic polymer having sulfonic acid groups with an accelerator, with water or an aromatic hydroxy compound being used as solvent.

[0043] In one aspect of the present invention, the aromatic polymer having a sulfonic acid group may be selected from polystyrene having a sulfonic acid group or a styrene-divinylbenzene copolymer having a sulfonic acid group, preferably a styrene-divinylbenzene copolymer having a sulfonic acid group.

[0044] In one aspect, the styrene-divinylbenzene copolymer having a sulfonic acid group may have divinylbenzene in an amount of about 1% to 15%, and preferably has divinylbenzene in an amount of about 10% to 15%.

[0045] In one aspect, the particle size of the aromatic polymer having sulfonic acid groups is in the range of about 500 microns to 1500 microns, preferably in the range of about 600 microns to 850 microns.

[0046] In one aspect of the present invention, the weight ratio of the ion exchange resin to the product obtained in the preparation of bisphenol is in the range of 1:1 to 1:5, preferably in the range of 1:1 to 1:3.

[0047] In one aspect of the present invention, the isomerization reaction is carried out at a temperature ranging from 40°C to 120°C and at atmospheric pressure, preferably at a temperature ranging from 60°C to 80°C and at atmospheric pressure.

[0048] In one aspect of the present invention, the isomerization reaction is carried out under aqueous conditions with a water content of 0.01% to 3.5% by weight, preferably with a water content of 0.05% to 0.5% by weight.

[0049] On the one hand, the product obtained from the preparation of bisphenol before the isomerization reaction occurs contains undesirable products, namely 4,4'-isopropylidenediphenol and 2,4'-isopropylidenediphenol.

[0050] In one aspect of the present invention, bisphenol is prepared by the condensation reaction of ketone and phenol, wherein the ketone can be selected from but not limited to acetone, diethyl ketone, methyl ethyl ketone, ethyl methyl ketone, isobutyl methyl ketone, cyclohexanone, acetophenone and 1,3-dichloroacetone; and the phenol can be selected from but not limited to unsubstituted phenol, alkylphenol, alkoxyphenol, naphthol, alkylnaphthol and alkoxynaphthol.

[0051] On the one hand, the ion exchange resin used in the isomerization reaction according to the present invention can be used in a batch system reaction in the form of slurry, and can also be used in a continuous system reaction in the form of fixed bed solid.

[0052] In one aspect, for batch system reactions and continuous system reactions, the reaction time can be in the range of about 1 to 24 hours. The liquid hourly space velocity (LHSV) can be in the range of about 0.015 to 10 hours. -1 within the range.

[0053] In one aspect of the present invention, the separation of the product having a higher bisphenol content is the crystallization of the 4,4'-isopropylidene diphenol product to separate the 4,4'-isopropylidene diphenol having a high purity.

[0054] The following examples are merely intended to illustrate various aspects of the present invention and are not intended to limit the scope of the present invention in any way.

[0055] Preparation of an accelerator for preparing an ion exchange resin according to the invention

[0056] The compound represented by structure (II)

[0057] Under argon atmosphere, about 5g of 2-pyridine carboxylic acid (pyridene carboxylic acid) and about 6g of cysteamine hydrochloride are dissolved in about 50mL of dichloromethane solvent. Then, a mixture solution of about 17g of dicyclohexylcarbodiimide and about 1g of 4-dimethylaminopyridine is added to about 20mL of dichloromethane solvent. The mixture is stirred at room temperature for about 24 hours under argon atmosphere. Solid is filtered out from the resulting mixture. Then, the filtrate is evaporated in vacuum. Afterwards, the filtrate is crystallized in an organic solvent or purified using a silica gel column. The solid obtained is separated and dried.

[0058] Preparation of ion exchange resin according to the present invention

[0059] Amberlyst 36 (Am36), an aromatic polymer of the styrene-divinylbenzene copolymer type having sulfonic acid groups, with a particle size ranging from about 600 microns to 850 microns, is used to prepare the ion exchange resin according to the present invention.

[0060] The promotor was dissolved in about 20 mL of deionized water and then added to about 20 g of styrene-divinylbenzene copolymer suspended in deionized water. Afterwards, the mixture was stirred at room temperature for about 1 hour. After stirring, the resulting mixture was loaded into a glass column and washed with deionized water. The residual sulfonic acid groups in the resulting solid were analyzed by titration with sodium hydroxide solution to determine the sulfonic acid groups (SO 3 H) Content before and after modification of the aromatic polymer. The percentage of sulfonic acid groups modified with the accelerator can be calculated by the following equation.

[0061]

[0062] Testing Isomerization Reactions Using Ion Exchange Resins

[0063] The isomerization efficiency of the product obtained from bisphenol preparation was tested by the following method using the ion exchange resin according to the present invention as a catalyst.

[0064] Before use, the ion exchange resin is dehydrated by contacting about 10 g of the ion exchange resin with about 100 g of phenol at a temperature of about 60° C. to 70° C. for about 15 minutes. This step is repeated 3 times. Then, about 1.5 g of the obtained ion exchange resin is added to a round-bottom flask. About 3 g of the product obtained by the condensation reaction of ketone and phenol to prepare bisphenol is contacted with the ion exchange resin under aqueous conditions having a desired water content, and then heated at a desired temperature. Then, the isomerization reaction of the undesirable product is carried out until the desired time is completed.

[0065] The following are examples of testing the product composition obtained by isomerization reaction using the ion exchange resin according to the present invention, wherein the methods and equipment used in the tests are commonly used methods and equipment and are not intended to limit the scope of the present invention.

[0066] The composition and amount of the products were analyzed by high performance liquid chromatography (Shimadzu LC-20AD) using a reverse phase Phenomenex Gemini-NX 5μ C18 column and a solvent system between water and acetonitrile as the mobile phase (flow rate of approximately 1 mL / min).

[0067] The conversion percentage (% conversion) of 2,4'-isopropylidene diphenol (2,4'BPA), the weight gain percentage (% weight gain) of 4,4'-isopropylidene diphenol (4,4'BPA) and the tar reduction percentage (% tar reduction) were calculated by the following equations.

[0068]

[0069]

[0070]

[0071] Table 1: Conversion percentage of 2,4'-isopropylidene diphenol and weight increase percentage of 4,4'-isopropylidene diphenol after isomerization reaction using different ion exchange resins

[0072]

[0073] As can be seen from Table 1, when the efficiency of comparative samples 1 to 5 was tested by isomerization reaction at a temperature of about 80° C. with samples 1 to 4 according to the present invention, it was found that the ion exchange resin according to the present invention produced high 2,4′-isopropylenediphenol conversion percentage and 4,4′-isopropylenediphenol weight increase percentage. The ion exchange resin according to the present invention using the promoter shown in structure (II) and cysteamine showed the highest efficiency.

[0074] In addition, when the efficiency was tested by isomerization reaction at a temperature of about 100° C. by comparing Comparative Sample 6 with Sample 4 according to the present invention, it was found that the ion exchange resin according to the present invention produced higher 2,4′-isopropylidene diphenol conversion percentage, 4,4′-isopropylidene diphenol weight increase percentage, and tar reduction percentage.

[0075] From the above results, it can be said that the ion exchange resin according to the present invention provides high efficiency in terms of conversion percentage of 2,4'-isopropylidene diphenol, weight increase percentage of 4,4'-isopropylidene diphenol and tar reduction percentage, as described in the object of the present invention.

[0076] Best Mode or Preferred Embodiment of the Invention

[0077] The best mode or preferred embodiment of the present invention is as provided in the description of the present invention.

Claims

1. A method for isomerizing a product obtained from the condensation reaction of a ketone and a phenol to produce bisphenol, the method comprising contacting the product obtained from the condensation reaction of a ketone and a phenol to produce bisphenol with an ion exchange resin under aqueous conditions for isomerization of undesirable products, the undesirable products comprising 2,4'-isopropylidene diphenol, and separating products having a higher bisphenol content, wherein: The ion exchange resin is an aromatic polymer having sulfonic acid groups which are modified by a promoter comprising a) at least one accelerator selected from the group consisting of the compound represented by structure (II) or the compound represented by structure (III): as well as b) at least one aminoalkylthiol promoter.

2. The method according to claim 1, wherein: The aminoalkylthiol is cysteamine.

3. The method according to claim 1 or 2, wherein: The accelerator comprises aminoalkylthiol in an amount of 10-90 mol% of the total accelerator.

4. The method according to claim 3, wherein: The accelerator comprises aminoalkylthiol in an amount of 30-70 mol% of the total accelerator.

5. The method according to claim 1, wherein: The sulfonic acid groups modified by the accelerator account for 10% to 20% of the total sulfonic acid groups.

6. The method according to claim 1 or 5, wherein: The sulfonic acid groups are modified by the accelerator via ionic bonds.

7. The method according to claim 1, wherein: The aromatic polymer having a sulfonic acid group is selected from polystyrene having a sulfonic acid group or a styrene-divinylbenzene copolymer having a sulfonic acid group.

8. The method according to claim 7, wherein: The aromatic polymer having a sulfonic acid group is a styrene-divinylbenzene copolymer having a sulfonic acid group.

9. The method according to claim 8, wherein: The styrene-divinylbenzene copolymer having a sulfonic acid group has divinylbenzene in an amount of 1% to 15% by weight.

10. The method according to claim 9, wherein: The styrene-divinylbenzene copolymer having a sulfonic acid group has divinylbenzene in an amount of 10% to 15% by weight.

11. The method according to claim 1, wherein: The particle size of the aromatic polymer having sulfonic acid groups is in the range of 500 microns to 1500 microns.

12. The method according to claim 11, wherein: The particle size of the aromatic polymer having sulfonic acid groups is in the range of 600 microns to 850 microns.

13. The method according to claim 1, wherein: The weight ratio of the ion exchange resin to the product prepared from bisphenol is in the range of 1:1 to 1:

5.

14. The method according to claim 13, wherein: The weight ratio of the ion exchange resin to the product prepared from bisphenol is in the range of 1:1 to 1:

3.

15. The method according to claim 1, wherein: The isomerization reaction is carried out in a temperature range of 40°C to 120°C and under atmospheric pressure.

16. The method according to claim 15, wherein: The isomerization reaction is carried out in the temperature range of 60°C to 80°C and under atmospheric pressure.

17. The method according to claim 1, wherein: The isomerization reaction is carried out under aqueous conditions with a water content of 0.01% to 3.5% by weight.

18. The method according to claim 17, wherein: The isomerization reaction is carried out under aqueous conditions with a water content of 0.05% to 0.5% by weight.

19. The method according to claim 1, wherein: The product obtained from the preparation of bisphenol further includes 4,4'-isopropylidene diphenol.

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