A catalyst for synthesizing bisphenol a and a method for preparing bisphenol a

Abstract

The application provides a bisphenol A synthesis catalyst and a bisphenol A preparation method. The catalyst comprises a cation exchange resin and a modified molecular sieve. The surface of the modified molecular sieve is connected with a modified group. The modified group is any one or both of a mercaptoalkyl group and an amine alkyl group. The modified molecular sieve can promote the generation of an active intermediate, an acetone carbon cation, in a reaction process, improve a reaction rate, and accelerate the reaction of the acetone carbon cation with phenol to generate bisphenol A. The mixed catalysts simultaneously consider the advantages of high activity of a hydrochloric acid method and high purity of a resin method, and the product has less free acid, and the product quality is higher than that of a hydrochloric acid catalysis method.

Description

Technical Field

[0001] This invention belongs to the field of organic synthesis technology, and in particular relates to a bisphenol A synthesis catalyst and a method for preparing bisphenol A. Background Technology

[0002] Bisphenol A, scientifically known as 4,4-diphenol propane, abbreviated as BPA, is a major raw material for the production of epoxy resins and polycarbonates. It is primarily used in the manufacture of various polymer materials, such as polycarbonate (PC), epoxy resins, polysulfone resins, phenolic unsaturated resins, polyaryl compounds, and polyetherimides; it is also used to manufacture heat stabilizers for polyvinyl chloride (PVC), rubber antioxidants, agricultural fungicides, antioxidants and plasticizers for paints and inks, and ultraviolet absorbers.

[0003] Bisphenol A is generally synthesized by the condensation of phenol and acetone under the catalysis of protic acids. Traditional industrial production has used sulfuric acid and hydrochloric acid as catalysts, which suffers from drawbacks such as low product quality, severe corrosion and pollution, and high production costs. Furthermore, the use of certain solid acids often results in them losing their activity due to carbonization. To address these shortcomings, research on ion exchange resins as catalysts for bisphenol A synthesis began in the early 1970s in various countries and is now widely used in industrial applications. This process significantly overcomes the deficiencies of traditional methods, allowing for easy separation of reactants and simplifying post-processing.

[0004] Ion exchange resins are less corrosive to equipment, have a high system operational reliability, and low investment costs. In the ion exchange resin method, the condensation reaction proceeds at a relatively high phenol-to-ketone ratio. Phenol acts as both a reactant and a solvent, improving the selectivity of the condensation reaction and resulting in low impurity content in the product. High-quality bisphenol A products can be obtained through a simple purification process. Currently, the ion exchange resin method has become the mainstream and development direction for bisphenol A production. However, it also suffers from low reaction selectivity and low process yield. Ion exchange resin catalysts have shortcomings in thermal stability and swelling properties. Furthermore, during the synthesis of bisphenol A, due to high reaction temperatures or strong catalyst acidity, the intermediate isopropylphenol carbocation easily undergoes dehydrogenation to generate the impurity IPP (isopropylphenol). IPP's boiling point and chemical properties are close to those of bisphenol A, making it difficult to completely separate in subsequent crystallization and distillation purification steps. It remains in the bisphenol A product, directly affecting its purity. During the purification process of bisphenol A, IPP is prone to double bond polymerization due to high temperature. Chromophores are formed due to the conjugation and cross-linking structure of the molecular chains, or the double bonds are oxidized at high temperature, thereby generating oxide impurities and coloring, which reduces the optical properties of polymer materials prepared from the bisphenol A product. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a bisphenol A synthesis catalyst and a method for preparing bisphenol A, so as to solve the problems of low reaction selectivity, low process yield, poor quality of reaction products, a large number of by-reaction products, and the inability to recover and utilize residual phenol in the bisphenol A preparation process in the prior art.

[0006] To achieve the above and other related objectives, the present invention provides a bisphenol A synthesis catalyst and a method for preparing bisphenol A.

[0007] The first aspect of the present invention provides a bisphenol A synthesis catalyst, the catalyst comprising: a cation exchange resin and a modified molecular sieve, wherein the surface of the modified molecular sieve is attached with a modifying group, the modifying group being any one or two selected from mercaptoalkyl and aminoalkyl groups.

[0008] Preferably, the modifying group is a mercaptoalkyl group or an aminoalkyl group.

[0009] Preferably, the mercaptoalkyl group includes any one or more of mercaptomethyl (-CH2-SH), mercaptoethyl (-CH2CH2-SH), mercaptopropyl (-CH2CH2CH2-SH), mercaptobutyl (-CH2CH2CH2CH2-SH), and mercaptopentyl (-CH2CH2CH2CH2CH2-SH).

[0010] More preferably, the mercaptoalkyl group is mercaptopropyl.

[0011] Preferably, the aminoalkyl group includes any one or more of aminomethyl (-CH2-NH2), aminoethyl (-CH2CH2-NH2), aminopropyl (-CH2CH2CH2-NH2), aminobutyl (-CH2CH2CH2CH2-NH2), and aminopentyl (-CH2CH2CH2CH2CH2-NH2).

[0012] More preferably, the aminoalkyl group is aminopropyl.

[0013] Preferably, the cation exchange resin is a styrene-based macroporous strong acid cation exchange resin.

[0014] Preferably, the molecular sieve is any one or more selected from MCM-41 molecular sieve, MCM-48 molecular sieve, SBA-15 molecular sieve, and ZSM-5 molecular sieve.

[0015] Preferably, the molecular sieve has a mesh size of 40 to 60.

[0016] Preferably, the volume ratio of cation exchange resin to modified molecular sieve in the catalyst is (2~20):1.

[0017] More preferably, the volume ratio of cation exchange resin to modified molecular sieve in the catalyst is (2~15):1; including but not limited to 2:1, 3:1, 5:1, 8:1, 10:1, 12:1, 15:1.

[0018] More preferably, the volume ratio of cation exchange resin to modified molecular sieve in the catalyst is (3~10):1.

[0019] Most preferably, the volume ratio of cation exchange resin to modified molecular sieve in the catalyst is (3~8):1.

[0020] Preferably, the modified molecular sieve is prepared by the following method: dispersing a template agent, an alkali source, a silicon source, and a silane coupling agent in water to form a mixed solution; subjecting the mixed solution to high-temperature crystallization to obtain a solid material; and acidifying and drying the solid material to obtain the modified molecular sieve.

[0021] The silane coupling agent is an aminosilane coupling agent and / or a mercaptosilane coupling agent.

[0022] More preferably, the template agent includes any one or more of hexadecyltrimethylammonium bromide (CTAB), dodecyltrimethylammonium bromide (DTAB), tetradecyltrimethylammonium bromide (TTAB), and octadecyltrimethylammonium chloride (STAC).

[0023] More preferably, the alkali source includes any one or more of sodium hydroxide, potassium hydroxide, ammonia, ethylenediamine, and tetramethylammonium hydroxide.

[0024] More preferably, the silicon source includes any one or both of tetraethyl orthosilicate (TEOS) and methyl orthosilicate (TMOS).

[0025] More preferably, the aminosilane coupling agent includes any one or more of aminopropyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropyl-trimethoxysilane, and N-(β-aminoethyl)-γ-aminopropyl-methyl-dimethoxysilane.

[0026] More preferably, the mercaptosilane coupling agent includes any one or more of mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-mercaptopropylmethyldimethoxysilane.

[0027] More preferably, the concentration of the template agent in the mixture solution is 0.1~5wt%.

[0028] More preferably, the concentration of the template agent in the mixture solution is 0.5~2wt%; including but not limited to 0.5wt%, 0.8wt%, 1wt%, 1.2wt%, 1.5wt%, and 2wt%.

[0029] Most preferably, the concentration of the template agent in the mixture solution is 0.8~1.2wt%.

[0030] More preferably, the concentration of the alkali source in the mixture solution is 0.02~2wt%.

[0031] More preferably, the concentration of the alkali source in the mixture solution is 0.1~2wt%; including but not limited to 0.1wt%, 0.5wt%, 0.8wt%, 1wt%, 1.2wt%, 1.5wt%, and 2wt%.

[0032] Most preferably, the concentration of the alkali source in the mixture solution is 0.6~1wt%.

[0033] More preferably, the concentration of the silicon source in the mixture solution is 10~30wt%.

[0034] More preferably, the concentration of the silicon source in the mixture solution is 15-25 wt%; including but not limited to 15 wt%, 16 wt%, 18 wt%, 20 wt%, 22 wt%, and 25 wt%.

[0035] Most preferably, the concentration of the silicon source in the mixture solution is 18-23 wt%.

[0036] The concentrations of each substance in the above mixture solution are based on the total mass of the mixture solution.

[0037] More preferably, the molar ratio of the silicon source to the silane coupling agent is 1:(0.01~0.5).

[0038] More preferably, the molar ratio of the silicon source to the silane coupling agent is 1:(0.05~0.3); including but not limited to 1:0.05, 1:0.1, 1:0.15, 1:0.2, 1:0.25, and 1:0.3.

[0039] Most preferably, the molar ratio of the silicon source to the silane coupling agent is 1:(0.1~0.3).

[0040] More preferably, the silane coupling agent is either an aminosilane coupling agent or a mercaptosilane coupling agent; the molar ratio of the aminosilane coupling agent to the mercaptosilane coupling agent is 1:(0.5~2); including but not limited to 1:0.5, 1:1, 1:1.5, and 1:2.

[0041] More preferably, the crystallization temperature is 80~130℃; including but not limited to 80℃, 90℃, 100℃, 110℃, 120℃, and 130℃.

[0042] More preferably, the crystallization time is 2 to 36 hours.

[0043] More preferably, the crystallization time is 5 to 20 hours; including but not limited to 5 hours, 8 hours, 10 hours, 12 hours, 15 hours, 18 hours, and 20 hours.

[0044] More preferably, the acidification involves immersing the solid material in an acidic ethanol solution. The purpose is to remove the template agent and protonate the amine matrix in the catalyst.

[0045] More preferably, the acid is hydrochloric acid.

[0046] More preferably, the concentration of acid in the acid-containing ethanol solution is 0.2~10wt%.

[0047] More preferably, the concentration of acid in the acidic ethanol solution is 0.5 to 3 wt%; including but not limited to 0.5 wt%, 0.8 wt%, 1.0 wt%, 1.2 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, and 3 wt%.

[0048] More preferably, the acidification temperature is 40~60℃; including but not limited to 40℃, 45℃, 50℃, 55℃, and 60℃.

[0049] More preferably, the acidification time is 2 to 5 hours; including but not limited to 2 hours, 3 hours, 4 hours, and 5 hours.

[0050] More preferably, the drying temperature is 60~120℃; including but not limited to 60℃, 70℃, 80℃, 90℃, 100℃, 110℃, and 120℃.

[0051] A second aspect of the present invention provides the use of the above-described catalyst in the preparation of bisphenol A.

[0052] The third aspect of the present invention provides a method for preparing bisphenol A, the method comprising: using phenol and acetone as raw materials, carrying out a catalytic reaction under the catalysis of the above-mentioned catalyst to obtain a reaction product.

[0053] Preferably, the preparation method further employs a phosphorus-containing auxiliary agent.

[0054] More preferably, the phosphorus auxiliaries include any one or more of triethyl phosphate, trimethyl phosphate, tributyl phosphate, triphenyl phosphate, and tetraethyl pyrophosphate.

[0055] Preferably, the molar ratio of phenol to acetone is (5~25):1.

[0056] More preferably, the molar ratio of phenol to acetone is (8~20):1; including but not limited to 8:1, 10:1, 12:1, 14:1, 15:1, 18:1, and 20:1.

[0057] More preferably, the molar ratio of phenol to acetone is (11~20):1.

[0058] Preferably, the temperature of the catalytic reaction is 50~100℃.

[0059] More preferably, the temperature of the catalytic reaction is 60~80℃; including but not limited to 60℃, 65℃, 70℃, 75℃, and 80℃.

[0060] More preferably, the temperature of the catalytic reaction is 60~75°C.

[0061] Preferably, the catalytic reaction takes 30 to 500 minutes.

[0062] More preferably, the catalytic reaction time is 30~420 min; including but not limited to 30 min, 50 min, 90 min, 120 min, 150 min, 180 min, 200 min, 300 min, 400 min, and 420 min.

[0063] More preferably, the catalytic reaction takes 30 to 180 minutes.

[0064] Most preferably, the catalytic reaction takes 35 to 120 minutes.

[0065] The time for the catalytic reaction is the residence time of phenol and acetone in the reactor.

[0066] Preferably, the volume ratio of cation exchange resin to modified molecular sieve in the catalyst is (2~20):1.

[0067] More preferably, the volume ratio of cation exchange resin to modified molecular sieve in the catalyst is (2~15):1; including but not limited to 2:1, 3:1, 5:1, 8:1, 10:1, 12:1, 15:1.

[0068] More preferably, the volume ratio of cation exchange resin to modified molecular sieve in the catalyst is (3~10):1.

[0069] Most preferably, the volume ratio of cation exchange resin to modified molecular sieve in the catalyst is (3~8):1.

[0070] The cation exchange resin is mixed evenly with the modified molecular sieve and then loaded into the reactor for use. During the reaction, a mixture of phenol and acetone is passed through the catalyst in the reactor to carry out the catalytic reaction.

[0071] Preferably, the molar ratio of the phosphorus auxiliary agent to acetone is (0.001~0.1):1.

[0072] More preferably, the molar ratio of the phosphorus auxiliary agent to acetone is (0.001~0.05):1; including but not limited to 0.001:1, 0.003:1, 0.006:1, 0.01:1, 0.02:1, 0.03:1, 0.04:1, and 0.05:1.

[0073] More preferably, the molar ratio of the phosphorus auxiliary agent to acetone is (0.001~0.01):1.

[0074] Preferably, the preparation method further includes a post-processing step, which sequentially includes a dehydration section, a crystallization section, and a devolatilization section.

[0075] Preferably, the dehydration section includes vacuum distillation of the reaction product at 0.05~0.2 bar and 45~85°C to obtain the dehydrated product.

[0076] The bottom material of the dehydration tower after the dehydration section includes phenol and bisphenol A. The distillate after the dehydration section includes acetone, water, and a large amount of phenol, which is then processed in subsequent recycling stages.

[0077] Preferably, the crystallization section includes suspension crystallization of the dehydrated product at 55~65°C to obtain bisphenol A / phenol adduct crystals.

[0078] More preferably, the suspension crystallization time is 0.5 to 5 hours; for example, it can be 0.5 hours, 1 hour, 2 hours, 3 hours, 4 hours, or 5 hours.

[0079] More preferably, the crystallization stage can be a single crystallization, or a secondary crystallization, tertiary crystallization, or other multiple crystallization processes.

[0080] When multiple crystallizations are performed, after one crystallization, the remaining liquid is collected, and the phenol in the liquid is recovered by flash evaporation concentration before recrystallization.

[0081] Preferably, the devolatilization section includes a dephenolization treatment of the bisphenol A / phenol adduct crystallizer under a steam flow condition of 0.01~1 bar and 160~200°C to obtain bisphenol A.

[0082] Preferably, the post-processing further includes a phenol recovery step, which includes an extractive distillation section, a concentration section, and a cracking section.

[0083] More preferably, the extractive distillation section includes adding an organic extractant to the distillate from the dehydration section, allowing it to stand and separate into layers, then transferring the organic phase into a distillation column, and distilling phenol at a pressure of 0.05~1 bar and a top temperature of 50~130°C.

[0084] More preferably, the amount of the organic extractant added is 0.5 to 4 times the mass of the distillate.

[0085] More preferably, the organic extractant is 1-isopropylacetone.

[0086] More preferably, the distillation can be a single distillation, or a double distillation, a triple distillation, or other multiple distillations.

[0087] In a single distillation, low-boiling-point acetone is first distilled off under a pressure of 0.05-0.5 bar.

[0088] After one distillation, the bottom fraction, mainly composed of the extractant, and light fractions containing a large amount of phenol and a small amount of acetone are obtained.

[0089] During the second distillation, phenol is first distilled at atmospheric pressure and a top temperature of 90-130℃ to distill off the extractant for recovery; then the temperature is increased to distill off the phenol.

[0090] Preferably, the concentration section includes taking the liquid after the crystallization section and recovering phenol by flash evaporation.

[0091] More preferably, the flash evaporation pressure is 10 kPa and the temperature is 115~120℃.

[0092] Preferably, the pyrolysis section includes taking the liquid after the crystallization section and pyrolyzing it at 160~250°C under acid catalysis to obtain phenol.

[0093] More preferably, the acid in the above-mentioned pyrolysis section is sulfuric acid.

[0094] A third aspect of the present invention provides a bisphenol A obtained by the above preparation method.

[0095] Preferably, the IPP content in the bisphenol A is <0.2%.

[0096] More preferably, the IPP content in the bisphenol A is 0.01~0.16%; for example, it can be 0.01%, 0.05%, 0.06%, 0.08%, 0.1%, 0.12%, 0.15%, or 0.16%.

[0097] More preferably, the IPP content in the bisphenol A is 0.05~0.1%.

[0098] Preferably, the color intensity of the bisphenol A is <20 APHA.

[0099] More preferably, the bisphenol A has a color intensity of 5 to 20 APHA; for example, it can be 5 APHA, 9 APHA, 10 APHA, 12 APHA, 15 APHA, 19 APHA, or 20 APHA.

[0100] More preferably, the bisphenol A has a color intensity of 8 to 11 APHA.

[0101] As described above, the bisphenol A synthesis catalyst and the method for preparing bisphenol A of the present invention have the following beneficial effects:

[0102] 1. In the preparation of bisphenol A, this invention uses cation exchange resin and molecular sieve modified with modified groups as a mixed catalyst. The two catalysts can play a synergistic role, with high catalytic activity, high conversion rate and selectivity. The modified molecular sieve can promote the generation of acetone carbocation, an active intermediate, in the reaction process, increase the reaction rate, and accelerate its reaction with phenol to generate bisphenol A.

[0103] 2. The modified acidic molecular sieve used in this invention is simple to separate and activate. The mixed catalyst combines the advantages of high activity from the hydrochloric acid method and high purity from the resin method, resulting in less free acid in the product and higher product quality compared to the hydrochloric acid catalytic method. The molecular sieve and cation exchange resin are used in combination, and the mixed catalyst can be acidified and activated together without separation. The activated catalyst can then be recycled, reducing catalyst costs.

[0104] 3. Adding a phosphorus-containing auxiliary agent during the preparation of bisphenol A serves as a soft base to stabilize the intermediate cation and inhibit the dehydrogenation of the intermediate cation to form IPP.

[0105] 4. The bisphenol A prepared by the method of the present invention has a color of <20 APHA and an IPP content of <0.2%, which meets the industry requirements for polycarbonate grade bisphenol A.

[0106] 5. The preparation method of this invention does not use corrosive liquid acid catalysts, the operation process is simple, and the production equipment is not too demanding. After the reaction, pure and high-quality bisphenol A can be obtained by dehydration, recrystallization and devolatilization. No complicated separation and purification post-processing work is required, which is suitable for large-scale industrial production.

[0107] 6. In this invention, phenol in the reaction solution is recovered and reused through multiple steps such as dehydration, extraction, distillation, flash evaporation and acid cracking, which greatly reduces the consumption of phenol per unit, making the whole process stable and feasible from an economic point of view, reducing production costs and ensuring product quality. Attached Figure Description

[0108] Figure 1 The diagram shows a process flow diagram of the bisphenol A preparation process in this invention. Detailed Implementation

[0109] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0110] It should be noted that the process equipment or apparatus not specifically mentioned in the following embodiments are all conventional equipment or apparatus in the art.

[0111] Furthermore, it should be understood that the existence of other method steps before or after the combined steps, or the insertion of other method steps between these explicitly mentioned steps, does not preclude the presence of other method steps before or after the combined steps, unless otherwise stated. It should also be understood that the combined connection relationship between one or more devices / apparatus mentioned in this invention does not preclude the existence of other devices / apparatus before or after the combined devices / apparatus, or the insertion of other devices / apparatus between these explicitly mentioned devices / apparatus. Moreover, unless otherwise stated, the numbering of each method step is merely a convenient tool for identifying each method step, and not for limiting the order of the method steps or defining the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0112] Before further describing specific embodiments of the present invention, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments described below; it should also be understood that the terminology used in the embodiments of the present invention is for describing specific embodiments and not for limiting the scope of protection of the present invention; in the specification and claims of the present invention, unless otherwise expressly stated in the text, the singular forms "a", "an" and "this" include the plural forms.

[0113] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in the present invention, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art. In addition to the specific methods, apparatus, and materials used in the embodiments, based on the knowledge of the prior art possessed by one of ordinary skill in the art and the description of this invention, any prior art methods, apparatus, and materials similar to or equivalent to those described, apparatus, and materials in the embodiments of this invention may be used to implement the present invention.

[0114] The method for preparing bisphenol A in this application includes: a reaction section, a dehydration section, a crystallization section, a devolatilization section, an extractive distillation section, a concentration section, and a cracking section. A schematic flow chart of this process is shown below. Figure 1 As shown.

[0115] The reaction section also includes the preparation of a catalyst, which is a mixed catalyst of cation exchange resin and modified molecular sieve.

[0116] In some specific embodiments of the present invention, the modified molecular sieve is an amino and thiol-modified MCM-41 molecular sieve, and its specific preparation method includes the following steps:

[0117] S1. Using hexadecyltrimethylammonium bromide (CTAB) as a template agent, sodium hydroxide as an alkali source, tetraethyl orthosilicate (TEOS) as a silicon source, aminopropyltriethoxysilane (APTES) as an aminosilane coupling agent, and mercaptopropyltrimethoxysilane (MPTMS) as a mercaptosilane coupling agent, the components are dispersed in water to form a mixed solution.

[0118] S2. After thoroughly mixing the mixture, transfer it to a crystallization vessel for high-temperature crystallization.

[0119] S3. Separate the crystalline solid, wash with water to remove residual alkali, and immerse it in hydrochloric acid ethanol solution for acidification reaction.

[0120] S4. Dry the acidified solid and compress it into tablets to obtain the modified MCM-41 molecular sieve.

[0121] In the above process, the concentration of the template agent in the mixture solution is 0.8~1.2wt%; preferably 1wt%.

[0122] In the above process, the concentration of the alkali source in the mixture solution is 0.6~1wt%; preferably 0.8wt%.

[0123] In the above process, the concentration of silicon source in the mixed solution is 18~23wt%; preferably 21wt%.

[0124] In the above process, the molar ratio of silicon source to aminosilane coupling agent is 1:(0.05~0.15); preferably 1:0.1.

[0125] In the above process, the molar ratio of silicon source to mercaptosilane coupling agent is 1:(0.05~0.15); preferably 1:0.1.

[0126] In the above process, the crystallization temperature is 80~120℃; preferably 100℃.

[0127] In the above process, the crystallization time is 5 to 15 hours; preferably 12 hours.

[0128] In the above process, the concentration of hydrochloric acid in the hydrochloric acid ethanol solution is 0.5~5wt%; preferably 1wt%.

[0129] In the above process, the acidification temperature is 45~55℃; preferably 50℃.

[0130] In the above process, the acidification time is 3 to 5 hours; preferably 4 hours.

[0131] In the above process, the drying temperature is 80~100℃; preferably 90℃.

[0132] In some specific embodiments of the present invention, the reaction section includes the following steps:

[0133] S1. The cation exchange resin and modified molecular sieve are mixed and then loaded into the reactor.

[0134] S2. Phenol, acetone and phosphorus additives are mixed and then heated in a heat exchanger.

[0135] S3. The heated mixture enters the reactor for catalytic reaction.

[0136] In the above process, the volume ratio of cation exchange resin to modified molecular sieve is (2~15):1; preferably (3~8):1.

[0137] In the above process, the molar ratio of phenol to acetone is (10~25):1, preferably 11:1.

[0138] In the above process, the molar ratio of acetone to phosphorus auxiliaries is 1:(0.005~0.01), preferably 0.006.

[0139] In the above process, the temperature of the heated mixture is 60~80℃.

[0140] In the above process, the residence time of the mixed gas in the reactor is 90~420 min; preferably 90~200 min.

[0141] In some specific embodiments of the present invention, a dehydration section is also included after the reaction section.

[0142] The dehydration section includes transferring the reactants into a dehydration tower, and distilling off acetone, water, and some phenol under reduced pressure at a pressure of 0.05~0.2 bar and a temperature of 45~85℃ to obtain the dehydrated product.

[0143] In some specific embodiments of the present invention, a crystallization section is included after the dehydration section.

[0144] The crystallization process includes primary crystallization and secondary crystallization.

[0145] The primary crystallization process includes: placing the dehydrated product in a crystallization vessel 1 and performing suspension crystallization at 55-65°C for 1-3 hours to obtain bisphenol A / phenol adduct crystals.

[0146] In the above process, before the dehydrated product enters crystallization kettle 1, the content of bisphenol a is 10-20% and the content of phenol is 80-90%.

[0147] In some specific embodiments of the present invention, a concentration section is also included after the first crystallization.

[0148] The concentration section includes pumping the remaining solution in crystallization vessel 1 into a flash tank, concentrating it by removing phenol, and recovering the phenol.

[0149] In the above process, the flash evaporation temperature is 115–120℃ and the pressure is 10 kPa.

[0150] In the above process, after flash evaporation and concentration, the content of bisphenol A in the solution is 20-35%.

[0151] In some specific embodiments of the present invention, secondary crystallization is included after the concentration stage.

[0152] The secondary crystallization includes: placing the flash-concentrated solution in crystallization vessel 2 and performing suspension crystallization at 40~60℃ for 1-3 hours to obtain bisphenol A / phenol adduct crystals.

[0153] In some specific embodiments of the present invention, a pyrolysis section is also included after secondary crystallization.

[0154] The pyrolysis section includes the following steps:

[0155] S1. Take the liquid after secondary crystallization, and use sulfuric acid as a catalyst to convert the isomers and residual bisphenol A in the liquid into phenol by cracking at 160-250℃.

[0156] In some specific embodiments of the present invention, a devolatilization section is included after the crystallization section.

[0157] The devolatilization section involves placing the bisphenol A / phenol adduct crystals obtained from primary and secondary crystallization in a butterfly stripping tower, stripping the solids with steam at 0.02-1 bar and 160-200°C to obtain pure bisphenol A and recover the separated phenol.

[0158] In some specific embodiments of the present invention, an extractive distillation section is included after the dehydration section.

[0159] The purpose of the extractive distillation section is to recover acetone, water, and phenol distilled from the dehydration section.

[0160] The extractive distillation section includes the following steps:

[0161] S1. Place the materials obtained from the dehydration section, including acetone, water, and phenol, into an extraction vessel, add 0.5-3 times the mass of the material as extractant, stir and mix well, and let stand to separate the layers, separating the aqueous phase and retaining the organic phase.

[0162] S2. The organic phase is transferred into distillation column 1 and distilled under reduced pressure to obtain the bottom fraction, which is mainly composed of the extractant, and the fraction containing acetone, phenol and other light components. The extractant is then pumped into the extraction vessel for recycling.

[0163] S3. Transfer the light fraction from S2 into distillation column 2 for secondary distillation to separate phenol and acetone, and recover them separately.

[0164] In the above process, the extractant is 1-isopropylacetone.

[0165] In the above process, acetone is first distilled off in distillation column 1 at a pressure of 0.05-0.5 bar.

[0166] In the above process, phenol is distilled in distillation column 2 at atmospheric pressure and a top temperature of 90-130℃, and the extractant is distilled off for recovery. Then, the temperature is raised to distill off phenol for recovery.

[0167] Example 1

[0168] This embodiment 1 provides a method for preparing bisphenol A and a bisphenol A product obtained by this method. The specific preparation method includes the following steps:

[0169] Preparation of S1, amine and thiol modified MCM-41 molecular sieves

[0170] Weigh 4.3 kg of water, add 58.7 g of CTAB and 48.0 g of sodium hydroxide, heat the material to 80 °C to dissolve and stir evenly. Continue adding 1.25 kg of tetraethyl orthosilicate (TEOS) (M208.3, 1 eq, 6 mol), stirring continuously during the addition to ensure thorough mixing. Then add 117.8 g of aminopropyltriethoxysilane (APTES) (M221.4, 0.1 eq, 0.6 mol) and 132.8 g of mercaptopropyltrimethoxysilane (MPTMS) (M196.3, 0.1 eq, 0.6 mol), and continue stirring for 15 min. Transfer the material to a 2 L stainless steel reactor with a polytetrafluoroethylene liner, heat to 100 °C, maintain the temperature, and slowly stir to crystallize for 12 h. After cooling to room temperature, filter the solids in the reactor and wash with water until neutral. The obtained solid was added to 1.95 kg of ethanol, and 57 g of 35% concentrated hydrochloric acid was added. The mixture was heated to 50°C and stirred for 4 hours. The solid was separated by filtration again. The solid was washed with ethanol and dried at 90°C. The powder solid was compressed into tablets and crushed. 40-60 mesh particles were sieved and stored in a desiccator.

[0171] S2, Catalyst loading

[0172] The reactor is a fixed-bed adiabatic reactor. The cation exchange resin and modified molecular sieve are mixed evenly at a volume ratio of 8:1 and then loaded into the fixed bed. The catalyst loading rate is 60%. The bottom of the hollow cylinder of the reactor is equipped with multiple layers of baffles, and the catalyst is laid on the baffles. The material passes through the catalyst from top to bottom. The effective volume of the reactor is 150L, ​​and the operating pressure is atmospheric pressure to 2MPa. The cation exchange resin is Suqing brand styrene-based macroporous strong acid cation exchange resin produced by Jiangsu Suqing.

[0173] S3, Raw material input and catalytic reaction proceed.

[0174] 252.2 kg of phenol (94.1 Da, 2.68 kmol, 11 eq) was added to feedstock tank 1, and 14.2 kg of acetone (58.1 Da, 244 mol, 1 eq) and 266.4 g of triethyl phosphate (182 Da, 1.46 mol, 0.006 eq) were added to feedstock tank 2 and mixed thoroughly. Feedstock 1 was pumped out of feedstock tank 1 at a rate of 7.2 kg / min, and feedstock 2 was pumped out of feedstock tank 2 at a rate of 413 g / min (the average residence time of the materials in the reactor was 35 min). After thorough mixing, the two feedstocks entered a heat exchanger, where they were heated to 75°C before entering the reaction bed for reaction. The reaction liquid flowed out of the reaction bed and entered storage tank 1 for temporary storage and cooling. The reaction continued until the material was exhausted. The total amount of material in storage tank 1 was 267.0 kg. The moisture content of the material was sampled and quantified (according to standard: JJG1154-2018, the moisture content of the material was determined using a Karl Fischer moisture analyzer), and its components were analyzed by gas chromatography. The products and by-products were quantitatively analyzed. The material contained 1.48% moisture, 18.46% bisphenol A product, 49.08% phenol, and 0.52% acetone. The calculated reaction conversion rate was 96.2%, and the selectivity was 97.1%.

[0175] Conversion rate formula: ;

[0176] Selective formula: .

[0177] S4, Crystallization and Separation of Bisphenol A

[0178] The material in storage tank 1 was pumped into a dehydration tower. At a pressure of 0.1 bar and a top temperature of 46°C, a fraction containing acetone, water, and a portion of phenol, totaling 4.78 kg (containing 2.6% phenol and 14.5% acetone), was distilled off and collected in storage tank 2 for subsequent recovery and extraction. The remaining 261.96 kg of reaction liquid was fed into crystallization vessel 1 for bisphenol A crystallization. The temperature of the material in the vessel was lowered to 60°C and stirred for 2 hours, separating the precipitated adduct crystals of bisphenol A and phenol, totaling 56.56 kg. The remaining 205.40 kg of reaction liquid was pumped into a heat exchanger and then into a flash evaporator. The heat exchanger outlet temperature was 115–120°C, and the flash evaporation pressure was 10 kPa. 175.71 kg of phenol (99.6% purity) was recovered through flash evaporation, leaving a remaining material of 29.70 kg, containing 30.8% bisphenol A, 65.5% phenol, and 0.5% acetone. Crystallization vessel 2 contained 60 kg of bisphenol A crystallization mother liquor (containing 30% bisphenol A and 65% phenol). The remaining reaction liquid was combined into crystallization vessel 2, and the temperature inside the vessel was lowered to 55°C and stirred for 2 hours. The adduct crystals of bisphenol A and phenol were separated, totaling 11.78 kg. The adduct crystals obtained from crystallization vessels 1 and 2 were transferred to the subsequent devolatilization stage. 17.91 kg of mother liquor from the remaining liquid in crystallization vessel 2 was extracted and sent to the subsequent pyrolysis stage. The remaining mother liquor was combined and sent to the next batch of pyrolysis.

[0179] S5. Deviation of the adduct crystals yielded bisphenol A product.

[0180] The 68.34 kg of adduct crystals from step S4 were fed into a dish stripper. Under the action of a steam flow of 0.05 bar and 190°C, 19.95 kg of phenol was removed from the material and recovered, yielding 48.39 kg of anhydrous bisphenol A, which was then fed into the granulation section. The single-pass yield was calculated to be 86.9%. Samples of the obtained bisphenol A product were taken, and the color of the bisphenol A product was determined to be 18 APHA according to standards GB / T 28113-2011 and GB / T 3143-1982, meeting the industry requirements for polycarbonate-grade bisphenol A.

[0181] S6, Phenol Recovery

[0182] Add 7.17 kg of the extractant 1-isopropylacetone to the 4.78 kg fraction collected in storage tank 2 in step S4 above. After stirring for 15 min, allow the mixture to stand and separate into layers. After separating the aqueous phase, the organic phase enters distillation column 1. At a pressure of 0.1 bar and a low temperature, acetone is first distilled off for recovery. Then, the temperature is raised to 120°C to distill off the extractant and phenol fractions. The fractions enter distillation column 2, where the extractant is distilled off at atmospheric pressure and 120°C, and then the temperature is raised to distill off the phenol.

[0183] In step S4 above, 17.91 kg of mother liquor extracted from crystallization vessel 2 was reacted at 180°C for 4 h under the action of 100 g of anhydrous sulfuric acid. During this period, 16.34 kg of phenol was recovered by distillation.

[0184] S7, Cation Exchange Resin Regeneration

[0185] After multiple catalytic reactions, the cation exchange resin needs to be regenerated. Specifically, after rinsing the catalyst bed with deionized water, a 10% hydrochloric acid solution is prepared and slowly passed through the resin column at a flow rate of 2 BV / h (bed volume / hour) for 1.5 hours to completely replace the metal ions (such as Ca²⁺ and Mg²⁺) adsorbed on the molecular sieve. The hydrochloric acid is then replaced with deionized water and rinsed at the same flow rate until the pH of the effluent is close to neutral (pH > 5). Finally, the catalyst bed is purged with nitrogen at 50°C for 30 minutes, and it can then be reused in the next synthesis.

[0186] Example 2

[0187] The difference between Example 2 and Example 1 is that in step S3, the reactants are heated to 60°C and then introduced into the reaction bed for reaction. The rest of the processing is the same as in Example 1.

[0188] Example 3

[0189] The difference between Example 3 and Example 1 is that in step S3, the reactants are heated to 80°C and then introduced into the reaction bed for reaction. All other treatments are the same as in Example 1.

[0190] Example 4

[0191] The difference between Example 4 and Example 1 is that in step S3, the feeding rate of material 1 in raw material tank 1 is set to 1.65 kg / min, and the feeding rate of material 2 in raw material tank 2 is set to 94.6 g / min. The feeding rates of raw material 1 and raw material 2 are increased synchronously, and the feeding ratio of the two materials remains unchanged. Only the residence time of the materials in the device is changed to 90 min. All other processes are the same as in Example 1.

[0192] Example 5

[0193] The difference between Example 5 and Example 1 is that in step S3, the feeding rate of material 1 in raw material tank 1 is set to 827.1 g / min, and the feeding rate of material 2 in raw material tank 2 is set to 47.3 g / min. The feeding rates of raw material 1 and raw material 2 are increased synchronously, and the feeding ratio of the two materials remains unchanged. Only the residence time of the materials in the device is changed to 180 min. All other processes are the same as in Example 1.

[0194] Example 6

[0195] The difference between Example 6 and Example 1 is that in step S3, the feeding rate of material 1 in raw material tank 1 is set to 354.5 g / min, and the feeding rate of material 2 in raw material tank 2 is set to 20.3 g / min. The feeding rates of raw material 1 and raw material 2 are increased synchronously, and the feeding ratio of the two materials remains unchanged. Only the residence time of the materials in the device is changed to 420 min. All other processes are the same as in Example 1.

[0196] Example 7

[0197] The difference between Example 7 and Example 1 is that the feeding ratio of material 1 and material 2 is changed. In step S3, the feeding rate of material 2 in raw material tank 2 is set to 52.0 g / min, while the feeding rate of material 1 in raw material tank 1 is maintained at 1.24 kg / min, so that the molar equivalent of phenol relative to acetone in the reaction is 15 eq. The feeding is stopped after the reaction has proceeded for 30 min. All other treatments are the same as in Example 1.

[0198] Example 8

[0199] The difference between Example 8 and Example 1 is that the feeding ratio of material 1 and material 2 is changed. In step S3, the feeding rate of material 2 in raw material tank 2 is set to 39.0 g / min, while the feeding rate of material 1 in raw material tank 1 is maintained at 1.24 kg / min, so that the molar equivalent of phenol relative to acetone in the reaction is 20 eq. The feeding is stopped after the reaction has proceeded for 30 min. All other treatments are the same as in Example 1.

[0200] Example 9

[0201] The difference between Example 9 and Example 1 is that the feeding ratio of material 1 and material 2 is changed. In step S3, the feeding rate of material 2 in raw material tank 2 is set to 78.0 g / min, while the feeding rate of material 1 in raw material tank 1 is maintained at 1.24 kg / min, so that the molar equivalent of phenol relative to acetone in the reaction is 10 eq. The feeding is stopped after the reaction has proceeded for 30 min. All other treatments are the same as in Example 1.

[0202] Example 10

[0203] The difference between Example 10 and Example 1 is that in step S2, the mixing ratio of cation exchange resin and modified molecular sieve is replaced with 3:1, while the rest of the treatment is the same as in Example 1.

[0204] Example 11

[0205] The difference between Example 11 and Example 1 is that in step S2, the mixing ratio of cation exchange resin and modified molecular sieve is replaced with 20:1, while the rest of the treatment is the same as in Example 1.

[0206] Comparative Example 1

[0207] The difference between Comparative Example 1 and Example 1 is that no molecular sieve is added in step S2, only cation exchange resin is used as a catalyst, the loading amount remains unchanged, and the rest of the treatment is the same as in Example 1.

[0208] Comparative Example 2

[0209] The difference between Comparative Example 2 and Example 1 is that triethyl phosphate is not added in step S3, while the rest of the treatment is the same as in Example 1.

[0210] Comparative Example 3

[0211] The difference between Comparative Example 3 and Example 1 is that no molecular sieve is added in step S2, only cation exchange resin is used as a catalyst, the loading amount remains unchanged, and no triethyl phosphate is added in step S3. All other treatments are the same as in Example 1.

[0212] Comparative Example 4

[0213] The difference between Comparative Example 4 and Example 1 is that the molecular sieve added in step S2 is an unmodified MCM-41 molecular sieve, the loading amount remains unchanged, and the rest of the treatment is the same as in Example 1.

[0214] The components in Examples 2-11 and Comparative Examples 1-4 were determined using the same method as in Example 1, and the conversion rate and reaction selectivity of the reaction process were calculated. The subsequent processing procedure remained consistent with Example 1. The obtained bisphenol A product was sampled and its color was measured using the same method. Specific results are shown in Table 1.

[0215] Table 1. Reaction conversion rate, selectivity, and bisphenol A performance data for Examples 1-11 and Comparative Examples 1-4.

[0216] Experimental Example Reaction temperature / ℃ Dwell time / min Phenol equivalent / eq Resin / Molecular sieve ratio Conversion rate / % Selectivity / % Product color / APHA IPP content / % Example 1 75 35 11 8:1 96.2 97.1 11 0.095 Example 2 60 120 11 8:1 91.3 97.5 10 0.085 Example 3 80 120 11 8:1 97.1 94.4 16 0.135 Example 4 75 90 11 8:1 89.5 97.2 11 0.092 Example 5 75 180 11 8:1 97.4 97.1 13 0.111 Example 6 75 420 11 8:1 97.7 96.8 14 0.118 Example 7 75 120 15 8:1 96.4 97.5 9 0.077 Example 8 75 120 20 8:1 96.9 97.8 9 0.079 Example 9 75 120 10 8:1 96.5 96.2 13 0.110 Example 10 75 120 11 3:1 97.2 97.5 9 0.080 Example 11 75 120 11 20:1 88.7 95.7 19 0.160 Comparative Example 1 75 120 11 / 75.2 93.5 33 0.377 Comparative Example 2 75 120 11 8:1 82.6 95.7 27 0.241 Comparative Example 3 75 120 11 / 44.2 92.2 73 0.607 Comparative Example 4 75 120 11 8:1 74.1 85.5 55 0.521

[0217] As can be seen from the results in Table 1, the conversion rates in Examples 1-11 were all >85% and the selectivity was all >94%, the color of bisphenol A was all <20 APHA, and the IPP content was all <0.2%. In contrast, the products in the comparative examples had higher color and higher IPP impurity content, which did not meet the standards for industrial-grade bisphenol A.

[0218] Compared to Example 1, Comparative Example 1 used only cation exchange resin as a catalyst, which significantly reduced the conversion rate and resulted in bisphenol A with high color, poor quality, and high impurity content. In Comparative Example 2, no phosphorus-containing additive was added, and the cationic intermediate was easily converted into impurity IPP, increasing its content and inhibiting the reaction, thus reducing the conversion rate and resulting in poor quality bisphenol A. In Comparative Example 3, neither modified molecular sieve catalyst nor phosphorus-containing additive was used, resulting in a significant reduction in conversion rate to only 44.2%, and poor quality bisphenol A with high IPP content. In Comparative Example 4, unmodified MCM-41 molecular sieve was used, which reduced both conversion rate and selectivity, resulting in poor quality bisphenol A with high IPP content.

[0219] The comparison of Examples 1-3 shows that reaction temperature affects conversion rate, bisphenol A color, and IPP content. Lowering the temperature leads to a lower conversion rate, but it is beneficial to reduce product color and IPP content. Examples 1 and 4-6 show that increasing the residence time increases the conversion rate, but increases product color and IPP content. Examples 1 and 7-9 show that increasing the amount of phenol, with the amount of acetone remaining constant, is beneficial to reduce product color and IPP content. Examples 1 and 10-11 show that excessive addition of cation exchange resin in the mixed catalyst reduces the conversion rate, increases product color and IPP content, and deteriorates product quality.

[0220] In summary, this invention provides a novel method for preparing bisphenol A, which uses cation exchange resin and modified molecular sieve as a mixed catalyst and phosphorus-containing compounds as an auxiliary agent. This method can improve the reaction rate, reduce impurity generation, and produce bisphenol A of high quality that meets industrial-grade standards.

[0221] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any form or substance. It should be noted that those skilled in the art can make various improvements and additions without departing from the method of the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention. Any modifications, alterations, and equivalent changes made by those skilled in the art based on the above-disclosed technical content without departing from the spirit and scope of the present invention are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, and evolutions made to the above embodiments based on the essential technology of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A catalyst for the synthesis of bisphenol A, characterized in that, The catalyst comprises: a cation exchange resin and a modified molecular sieve, wherein the surface of the modified molecular sieve is attached with modified groups, which are mercaptoalkyl and aminoalkyl groups; the mercaptoalkyl groups include any one or more of mercaptomethyl, mercaptoethyl, mercaptopropyl, mercaptobutyl, and mercaptopentyl; the aminoalkyl groups include any one or more of aminomethyl, aminoethyl, aminopropyl, aminobutyl, and aminopentyl; the volume ratio of the cation exchange resin to the modified molecular sieve in the catalyst is (2~20):1; the molecular sieve is any one or more selected from MCM-41 molecular sieve, MCM-48 molecular sieve, SBA-15 molecular sieve, and ZSM-5 molecular sieve; the modified molecular sieve is prepared by the following method: a template agent, an alkali source, a silicon source, and a silane coupling agent are dispersed in water to form a mixed solution; the mixed solution is subjected to high-temperature crystallization to separate solid materials; the solid materials are acidified and dried to obtain the modified molecular sieve; the silane coupling agent is an aminosilane coupling agent and a mercaptosilane coupling agent.

2. The catalyst according to claim 1, characterized in that, The aminosilane coupling agent includes any one or more of aminopropyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropyl-trimethoxysilane, and N-(β-aminoethyl)-γ-aminopropyl-methyl-dimethoxysilane; And / or, the mercaptosilane coupling agent includes any one or more of mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-mercaptopropylmethyldimethoxysilane; And / or, the concentration of the template agent in the mixture solution is 0.1~5wt%; And / or, the concentration of the alkali source in the mixture solution is 0.02~2wt%; And / or, the concentration of the silicon source in the mixture solution is 10~30 wt%; And / or, the molar ratio of the silicon source to the silane coupling agent is 1:(0.01~0.5). And / or, the silane coupling agent is either an aminosilane coupling agent or a mercaptosilane coupling agent; the molar ratio of the aminosilane coupling agent to the mercaptosilane coupling agent is 1:(0.5~2). And / or, the crystallization temperature is 80~130℃; And / or, the crystallization time is 2~36h; And / or, the acidification is performed by immersing the solid material in an acidic ethanol solution.

3. Use of the catalyst as described in any one of claims 1 to 2 in the preparation of bisphenol A.

4. A method for preparing bisphenol A, characterized in that, The preparation method includes: using phenol and acetone as raw materials, carrying out a catalytic reaction under the catalysis of any one of the catalysts as described in claims 1 to 2, to obtain the reaction product.

5. The preparation method according to claim 4, characterized in that, The preparation method also employs phosphorus-containing auxiliaries; And / or, the molar ratio of phenol to acetone is (5~25):1; And / or, the temperature of the catalytic reaction is 50~100℃; And / or, the catalytic reaction takes 30 to 500 minutes; And / or, the volume ratio of cation exchange resin to modified molecular sieve in the catalyst is (2~20):

1.

6. The preparation method according to claim 5, characterized in that, The phosphorus adjuvant includes any one or more of triethyl phosphate, trimethyl phosphate, tributyl phosphate, triphenyl phosphate, and tetraethyl pyrophosphate; And / or, the molar ratio of the phosphorus auxiliary agent to acetone is (0.001~0.1):1; And / or, the preparation method further includes a post-processing step, wherein the post-processing sequentially includes a dehydration section, a crystallization section, and a devolatilization section.

7. The preparation method according to claim 6, characterized in that, The dehydration section includes vacuum distillation of the reaction product at 0.05~0.2 bar and 45~85°C to obtain the dehydrated product; The crystallization section includes suspension crystallization of the dehydrated product at 55~65℃ to obtain bisphenol A / phenol adduct crystals; The devolatilization section includes a dephenolization treatment of bisphenol A / phenol adduct crystals under a steam flow condition of 0.01~1 bar and 160~200℃ to obtain bisphenol A; And / or, the post-processing further includes a phenol recovery step, which includes an extractive distillation section, a concentration section, and a cracking section.

8. The preparation method according to claim 7, characterized in that, The extractive distillation section includes adding an organic extractant to the distillate from the dehydration section, allowing it to stand and separate into layers, then transferring the organic phase into a distillation column, where phenol is distilled at a pressure of 0.05~1 bar and a top temperature of 50~130℃. And / or, the concentration section includes taking the liquid after the crystallization section and recovering phenol by flash evaporation; And / or, the pyrolysis section includes taking the liquid after the crystallization section and pyrolyzing it at 160~250°C under acid catalysis to obtain phenol.

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