Hydrogenation catalyst, method of preparation and use thereof in the preparation of hydrogenated bisphenol a

Abstract

The present application relates to a kind of hydrogenation catalyst, preparation method and its application in the preparation of hydrogenated bisphenol A.The preparation application includes bisphenol A, hydrogenation catalyst and solvent isopropyl alcohol, at temperature 150~200 ℃, pressure 6~9MPa.The hydrogenation catalyst in the active component with nickel and iridium, copper as catalytic adjuvant, metal oxide as carrier.In the present application, the conversion rate of bisphenol A can reach 100%, while the selectivity of hydrogenated bisphenol A is greater than 99%, and the purity of hydrogenated bisphenol A can be above 99%.

Description

Technical Field

[0001] This invention relates to the field of chemical technology, and in particular to a hydrogenation catalyst, its preparation method, and its application in the preparation of hydrogenated bisphenol A. Background Technology

[0002] Hydrogenated bisphenol A (HBPA), chemically known as 2,2-bis(4-hydroxycyclohexyl)propane, is a raw material for unsaturated polyester resins and epoxy resins. It is particularly used in components such as fiberglass, artificial marble, bathtubs, and electroplating tanks, exhibiting advantages such as water resistance, chemical resistance, thermal stability, and light stability. Hydrogenated bisphenol A can improve the weather resistance of epoxy resins, enabling its application in most outdoor and special environments.

[0003] The preparation of hydrogenated bisphenol A involves hydrogenating bisphenol A in solution under the action of a catalyst. This process falls under the category of aromatic compound hydrogenation, specifically benzene ring hydrogenation. Bisphenol A hydrogenation utilizes three main types of catalysts: metal framework catalysts, noble metal supported catalysts, and homogeneous catalysts. Typical reaction conditions are 50–250 °C and hydrogen pressure 1–30 MPa. Both batch and continuous hydrogenation processes can be employed. The key to its preparation lies in the selection of the hydrogenation catalyst and the optimization of the process.

[0004] Chinese patents CN1095690C and CN1100608C have developed a supported ruthenium catalyst for the hydrogenation of bisphenol A. This process uses a batch hydrogenation method, achieving a conversion rate of over 99% after 5 hours of reaction at 150 °C and 20 MPa. Chinese patent CN1375484A discloses a method for preparing hydrogenated bisphenol A in the presence of a ruthenium catalyst supported on silica. This method employs a fixed-bed hydrogenation process, with the hydrogenation reaction carried out at 50–250 °C and 0.5–15 MPa pressure. The molar ratio of hydrogen to bisphenol A is 6:1–30:1, achieving 100% conversion within 40 hours and an average selectivity of 96%. Chinese patent CN109678661A describes a method for hydrogenating bisphenol A using a fixed-bed reactor in the presence of a nickel catalyst and a solvent. The process conditions for the hydrogenation reaction of bisphenol A are: reaction temperature 120–200 °C, pressure 3–5 MPa, feed concentration 10–50%, conversion rate 100%, and average selectivity 98%.

[0005] Hydrogenated bisphenol A has three isomers. Studies have shown that the trans / trans isomer has greater application value, providing better mechanical properties in polymers. Patent CN102921440A uses a modified composite alumina as a support, with Pd, Ru, and Rh as active components. Using this catalyst, hydrogenation of bisphenol A at 7.8 MPa and 165 °C yields hydrogenated bisphenol A with a trans / trans isomer content of 55%. Patent CN109678661A uses a supported nickel-based catalyst, with lower alcohols or cyclohexane as solvents, employing a continuous hydrogenation process. The reaction temperature is 140–200 °C, and the pressure is 3–5 MPa. The crude product, after heating in a vacuum screw extruder, yields a product with a purity of 98%, of which the trans / trans isomer content is approximately 60%. Patent CN106866365A describes the use of a tubular fixed-bed reactor to hydrogenate bisphenol A at 140–180 °C and 5–9 MPa. By partially recycling the hydrogenation products, the ratio of trans / trans isomers can reach 60%. However, this increases the production cycle and energy consumption, which is not conducive to industrial application.

[0006] The catalysts used in the preparation of hydrogenated bisphenol A are mainly noble metals such as Pd, Ru, Rh, and Ni. Furthermore, the preparation process primarily involves batch hydrogenation in a reactor, resulting in high reaction pressures and low safety. Existing patented technologies, such as fixed-bed continuous hydrogenation for bisphenol A, require large quantities of recycled hydrogen due to the hydrogen circulation method, leading to significant energy consumption in the hydrogen compressor and relatively high industrial production costs. Among the three isomers of hydrogenated bisphenol A, the trans / trans isomer is more valuable in applications. Current technologies typically achieve a trans / trans isomer ratio of around 60%. To obtain a higher trans / trans isomer content, methods such as circulating hydrogenation, extending reaction time, and higher reaction temperatures are required, further increasing the production cycle and energy consumption, significantly raising production costs. Summary of the Invention

[0007] To overcome the shortcomings of existing technologies, such as low content of trans / trans isomers, this invention improves the fixed-bed hydrogenation reaction process conditions by using a continuous liquid-phase hydrogenation system to reduce the production cost of hydrogenated bisphenol A. Furthermore, this invention provides the hydrogenation catalyst used in the above process and its preparation method.

[0008] The objective of this invention can be achieved through the following technical solutions: One aspect of this invention is a hydrogenation catalyst.

[0009] The hydrogenation catalyst comprises a support, a catalyst promoter, and an active component dispersed on the support; the active component includes a first active component and a second active component; the first active component is nickel, and the second active component is iridium; the catalyst promoter is copper; the support is one or more of alumina, silicon oxide, or zirconium oxide; the support has a mesoporous structure with a pore size of 10-40 nm.

[0010] The second aspect of this invention provides a method for preparing the above-mentioned hydrogenation catalyst, comprising the following steps: S11: Carrier preparation: A diblock polymeric surfactant is added to an acid solution and stirred. The molar ratio of the diblock polymeric surfactant to the acid is 1:1500-60000. After it is completely dissolved, the carrier is added. Stirring continues until a precipitate is formed. The solution and precipitate after the reaction are transferred to a hydrothermal reactor and allowed to stand and cool. Then, they are filtered, washed, and dried. After one calcination, a powdered mesoporous carrier material is obtained. S12: Carrier impregnation: Prepare an aqueous solution of nickel and iridium in hydrochloric acid to form an active component solution; impregnate the catalyst and the mesoporous carrier material prepared in step S11 into the active component solution, so that the active component is uniformly attached to the carrier, and the impregnated carrier is obtained. S13: Preparation of hydrogenation catalyst: The support impregnated in step S12 is dried and then calcined twice to obtain the hydrogenation catalyst.

[0011] Furthermore, the diblock polymeric surfactant mentioned in step S11 is polyethylene oxide-polybutylene oxide.

[0012] Further, the acid solution in step S11 is one or more of hydrochloric acid, sulfuric acid, or nitric acid; the carrier is one or more of alumina, silicon oxide, or zirconium oxide; and the molar ratio of the carrier to the surfactant is 240-5000:1.

[0013] Furthermore, the support is preferably alumina and silicon oxide in a mass ratio of 1:1, which can be represented as a Ni-Ir-Cu / Al2O3-SiO2 hydrogenation catalyst.

[0014] Furthermore, the standing period specifically refers to standing at 80-150℃ for 8-24 hours; the first firing specifically refers to firing at 450-650℃ for 4-6 hours.

[0015] Further, the hydrochloric acid aqueous solution of nickel and iridium mentioned in step S12 specifically comprises a nickel chloride aqueous solution with a mass concentration of 20-30 wt% and an iridium chloride aqueous solution with a mass concentration of 0.3-1.0 wt%; the catalyst promoter is prepared by mixing copper chromite and hydrochloric acid solution in a mass ratio of 1:3, with an addition amount of 0.5-1.0 wt% copper chromite solution. Nickel has good hydrogenation performance, high mechanical strength, insensitivity to poisons, and good thermal conductivity. It can generate a strong interaction with hydrogenated bisphenol A, promoting the desorption of hydrogenated bisphenol A from the catalyst, thereby increasing the yield of hydrogenated bisphenol A, and also has high selective hydrogenation performance of the benzene ring. Iridium has excellent performance in both hydrogenation and dehydrogenation, and is a catalyst with good activity and stability. The presence of iridium-based catalysts can improve the overall catalyst activity, reduce the generation of by-products, improve the selectivity and purity of hydrogenated bisphenol A, and also play a certain role in increasing the content of trans / trans isomers. The addition of copper catalyst enhances the activity and selectivity of the main catalyst. Copper catalyst can remove hydrogenated bisphenol A from nickel or reduce the amount of potential hydrogen near the active site of the nickel catalyst, making it difficult for deep hydrogenation of hydrogenated bisphenol A to proceed, thereby improving the selectivity of hydrogenated bisphenol A.

[0016] Furthermore, the soaking time in step S12 is 1-10 h.

[0017] Further, the drying in step S13 is performed at 100-120 ℃ for 2-12 h; the secondary calcination is performed at 500-700 ℃ for 5-12 h.

[0018] The third aspect of this invention provides the application of the above-mentioned hydrogenation catalyst in the preparation of hydrogenated bisphenol A, comprising the following steps: S21: Catalyst loading and system replacement: The above-mentioned hydrogenation catalyst is loaded into the tubular fixed bed reactor, and the system is repeatedly flushed with nitrogen to ensure that no other impurity gases are present in the system. S22: Preparation of raw materials: Add bisphenol A and solvent and stir to dissolve, and control the mass concentration of bisphenol A to 10-30% to obtain a bisphenol A solution; S23: The prepared bisphenol A solution and high-pressure hydrogen are mixed in a tubular fixed-bed reactor and hydrogenated under the action of a hydrogenation catalyst to obtain hydrogenated products; three hydrogen inlets, a, b, and c, are set in the middle section of the tubular fixed-bed reactor, and high-pressure hydrogen enters the tubular fixed-bed reactor from the three hydrogen inlets a, b, and c. S24: Solvent recovery: The hydrogenation product described in step S23 is cooled by the first condenser and then enters the first-stage high-pressure separator for gas-liquid separation. The small amount of hydrogen and vaporized solvent separated by the first-stage high-pressure separator are cooled by the second condenser and then enter the second-stage high-pressure separator for gas-liquid separation. The trace amount of hydrogen separated is released as tail gas, and the separated hydrogenation product solution enters the solvent recovery tank for recycling. S25: Liquid product circulation: The hydrogenated product solution separated from the first-stage high-pressure separator is analyzed by online chromatograph to determine the ratio of the returned amount to the collected amount. The returned portion is metered and pressurized by the third metering pump and returned to the tubular fixed bed reactor for hydrogenation reaction again. The collected portion is the crude hydrogenated bisphenol A. The crude hydrogenated bisphenol A is metered into the crude product tank by the fourth metering pump. S26: Product Refining: The crude hydrogenated bisphenol A in the crude product tank passes through the fifth metering pump and the first preheater, and then enters the atmospheric pressure flash evaporator for atmospheric pressure solvent removal. The removed gaseous solvent is cooled by the third condenser and then enters the solvent recovery tank for recycling. The remaining liquid solution enters the scraped film evaporator for reduced pressure solvent removal and by-product removal. The upper part of the scraped film evaporator discharges light component impurities, and the lower part yields a hydrogenated bisphenol A product with relatively high purity. The relatively high purity hydrogenated bisphenol A product enters the molecular distillation column for further refining. The bottom of the molecular distillation column discharges heavy component impurities, and the molecular distillation column yields a high purity hydrogenated bisphenol A product.

[0019] Further, the fixed-bed reactor mentioned in step S21 is a tubular fixed-bed hydrogenation reactor, in which the hydrogenation catalyst is randomly packed, and the ratio of the fixed bed height of the hydrogenation catalyst to the tube diameter is 3-10:1; the solvent is one or more of ethanol, propanol, isopropanol or cyclohexane.

[0020] Furthermore, the temperature of the preheater is 80–100 °C; the operating temperature of the tubular fixed-bed reactor is 150–200 °C, the pressure is 6–9 MPa, and the liquid hourly space velocity is 2–4 h⁻¹. -1 Hydrogen:BPA (mol) = 10-30:1; the operating temperature of the preheater is 80-100 ℃; the operating temperature of the atmospheric pressure flash evaporator is 80-120 ℃ and the pressure is atmospheric pressure; the operating temperature of the scraped film evaporator is 180-220 ℃ and the pressure is -0.08 to -0.1 MPa.

[0021] Compared with the prior art, the beneficial technical effects achieved by the present invention are as follows: 1. The hydrogenation catalyst prepared by this invention has high activity and high conversion rate. The addition of iridium group improves the overall activity and stability of the catalyst, increases product purity and the content of trans / trans isomers. The addition of copper catalyst promoter makes deep hydrogenation of hydrogenated bisphenol A difficult to carry out, thereby improving the selectivity of hydrogenated bisphenol A.

[0022] 2. The alumina and silica composite support with mesoporous structure used in this invention has good porosity, high mechanical strength, and large specific surface area, which provides strong support for the release of catalyst activity.

[0023] 3. The present invention adopts a tubular fixed bed reactor with bottom inlet and top outlet, which allows the material to stay in the catalyst bed for a longer time, resulting in a better hydrogenation effect. The three gas inlets in the middle section of the reactor ensure that the solvent flow direction is consistent with the gas diffusion direction, which is conducive to the uniform distribution of the small amount of hydrogen and the full and thorough reaction.

[0024] 4. In the liquid product recycling system of the present invention, part of the crude hydrogenated bisphenol A product from the first-stage high-pressure separator is collected and part is re-entered into the reactor for reaction, which improves the purity of the product and greatly increases the content of trans / trans isomers. The existence of the liquid product recycling system eliminates the need for a hydrogen compression recycling system, which greatly reduces equipment investment and energy consumption.

[0025] 5. The scraped film evaporator of the present invention removes light components and molecular distillation removes heavy components, resulting in higher product purity and increased content of trans / trans isomers.

[0026] 6. The solvent recovery section in this invention allows for the reuse of the solvent, reducing costs.

[0027] 7. The Ni-Ir-Cu / Al2O3-SiO2 supported catalyst and the hydrogenation process and preparation method of hydrogenated bisphenol A described in this invention produce hydrogenated bisphenol A products with relatively stable performance and higher purity. Under this catalyst and process, the conversion rate of the hydrogenation reaction reaches 100%, the selectivity is >99%, the product purity is >99%, and the trans / trans isomer ratio reaches 65%. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the hydrogenated bisphenol A preparation process of the present invention.

[0029] Numbered in the diagram: 1. First metering pump; 3. Second metering pump; 12. Third metering pump; 13. Fourth metering pump; 15. Fifth metering pump; 2. Solvent feed tank; 4. First preheater; 16. Second preheater; 5. Tubular fixed-bed reactor; 6. First condenser; 8. Second condenser; 18. Third condenser; 7. First-stage high-pressure separator; 9. Second-stage high-pressure separator; 10. Solvent recovery tank; 11. Online chromatograph; 14. Crude product tank; 17. Atmospheric flash evaporator; 19. Scraped film evaporator; 20. Molecular distillation column. Detailed Implementation

[0030] The present invention will now be described in detail with reference to specific embodiments. Unless otherwise specified, all raw materials used in the present invention are commercially available or prepared according to conventional methods in the art. Many specific details are set forth in the following description to provide a thorough understanding of the invention. However, the invention can be practiced in many ways other than those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0032] Example 1 This embodiment provides a hydrogenation catalyst. The catalyst comprises a support and active components dispersed on the support. The active components include a first active component and a second active component; the first active component is nickel, and the second active component is iridium. The support is one or more of alumina, silicon oxide, or zirconium oxide. The support has a mesoporous structure with a pore size of 10-40 nm.

[0033] This embodiment also provides a method for preparing Ni-Ir-Cu / Al2O3-SiO2 hydrogenation catalyst, including the following steps: S11: Carrier Preparation: The diblock polymeric surfactant poly(ethylene oxide)-poly(butylene oxide) was added to a hydrochloric acid solution and stirred. The molar ratio of the diblock polymeric surfactant to the acid was 1:10000. After complete dissolution, silica and alumina were added, making the molar ratio of silica and alumina to the surfactant 1000:1. Stirring continued until a precipitate was formed. The precipitate and liquid were transferred to a hydrothermal reactor, allowed to stand and cool, and then filtered, washed, and dried. Calcination was performed to obtain a powdered mesoporous carrier material. The material was allowed to stand at 120 °C for 12 hours, cooled, filtered, washed, and dried at room temperature. Then, it was calcined at 500 °C for 5 hours to obtain a white powdered mesoporous carrier material.

[0034] S12: Carrier impregnation: Prepare a hydrochloric acid aqueous solution of nickel and iridium, which is a mixture of nickel chloride (20-30 wt%) and iridium chloride (0.3-1.0 wt%), to form an active component solution; impregnate the catalyst (a copper chromite solution prepared by mixing copper chromite and hydrochloric acid solution in a mass ratio of 1:3, with an addition of 0.5-1.0 wt%) and the mesoporous carrier material prepared in step S11 for 4 h, so that the active component is uniformly attached to the carrier, and the impregnated carrier is obtained.

[0035] S13: Preparation of hydrogenation catalyst: The support impregnated in step S12 is dried at 110 °C for 6 h, and then calcined at 600 °C for 8 h to obtain the hydrogenation catalyst.

[0036] This embodiment also provides a process for preparing hydrogenated bisphenol A using the above-mentioned hydrogenation catalyst, including the following steps: S21: Catalyst loading and system replacement: Open the upper end cap of the tubular fixed bed reactor 5, load the hydrogenation catalyst into the tubular fixed bed reactor 5, and after loading, close the upper end cap. Then, use nitrogen to check the airtightness of the reaction system. Nitrogen enters from the bottom of the reactor and the system is repeatedly flushed with nitrogen three times to ensure that there are no other impurity gases in the system. S22: Preparation of raw materials: Slowly add bisphenol A and isopropanol raw materials to solvent raw material tank 2 and stir to dissolve them completely. Control the mass concentration of bisphenol A to 10-30%. Add solvent or bisphenol A as needed according to the dissolution situation to obtain bisphenol A solution. S23: The prepared bisphenol A solution in the solvent raw material tank 2 is metered and pressurized by the second metering pump 3, and then mixed with the high-pressure hydrogen gas metered by the first metering pump 1 in the first preheater 4. Then, they enter the tubular fixed bed reactor 5 together and carry out the hydrogenation reaction under the action of the hydrogenation catalyst. The tubular fixed bed reactor 5 is equipped with three hydrogen gas inlets a, b, and c in the middle section of the reaction, and sufficient hydrogen gas is added in the direction of material flow. S24: Solvent recovery: After the hydrogenation product is cooled by the first condenser 6, it enters the first-stage high-pressure separator 7 for gas-liquid separation. The small amount of hydrogen and vaporized solvent separated are cooled by the second condenser 8 and then enter the second-stage high-pressure separator 9 for gas-liquid separation. The trace amount of hydrogen is released as tail gas, and the liquid solvent enters the solvent recovery tank 10 for recycling. S25: Liquid product circulation: The liquid in the lower part of the first-stage high-pressure separator 7 is analyzed by the online chromatograph 11 to determine the ratio of the amount of hydrogenated product solution returned to the amount of product collected. The returned part is metered and pressurized by the third metering pump 12 and returned to the tubular fixed bed reactor 5 for hydrogenation reaction again. The collected part is metered by the fourth metering pump 13 and enters the hydrogenated bisphenol A crude product tank 14. S26: Product Refining: The crude hydrogenated bisphenol A from the crude product tank 14 is then pumped through the fifth metering pump 15 into the second preheater 16, and then into the atmospheric flash tank 17 for atmospheric desolventizing. The gaseous solvent is cooled by the third condenser 18 and then enters the solvent recovery tank 10 for recycling. The liquid solution from the atmospheric flash tank 17 enters the scraped film evaporator 19 for desolventizing and removing by-products under reduced pressure. The upper part discharges light component impurities, and the lower part yields a hydrogenated bisphenol A product with relatively high purity, which then enters the molecular distillation column 20 for further refining. The bottom of the column discharges heavy component impurities, yielding a hydrogenated bisphenol A product with even higher purity, which is then processed into flakes for packaging.

[0037] In step S21, the hydrogenation catalyst in the tubular fixed-bed hydrogenation reactor is packed in a random manner, and the ratio of the fixed bed height of the hydrogenation catalyst to the tube diameter is 3-10:1.

[0038] The temperatures of the first preheater 4 and the second preheater 16 are 80–100 °C; the operating temperature of the tubular fixed-bed reactor 5 is 150–200 °C, the pressure is 6–9 MPa, and the liquid hourly space velocity is 2–4 h⁻¹. -1 The ratio of hydrogen to BPA (mol) is 10-30:1; the operating temperature of the atmospheric flash evaporator 17 is 80-120 ℃ and the pressure is atmospheric pressure; the operating temperature of the scraped film evaporator 19 is 180-220 ℃ and the pressure is -0.08 to -0.1 MPa.

[0039] Examples 2-16 The catalyst was loaded and hydrogenation reaction was carried out according to the above preparation process. The hydrogenation reaction effect under different catalyst and process conditions was investigated according to the reaction conditions in Table 1. Each condition was stable for more than 24 hours. The results of hydrogenation product solution analysis by online chromatograph 11 were used as the basis for the investigation. The specific implementation conditions and hydrogenation product analysis data are shown in Table 1: Table 1 Hydrogenation reaction conditions and data analysis

[0040] With increasing content of the active catalyst components Ni and Ir, the purity, selectivity, and trans / trans isomer content of the product after hydrogenation reaction all increase significantly, especially the trans / trans isomer content. When the Ni and Ir contents reach 25% and 0.5% respectively, further increasing the content of the active components no longer produces significant changes in the hydrogenation reaction effect.

[0041] The addition of copper additives makes deep hydrogenation of hydrogenated bisphenol A difficult, improving the selectivity of hydrogenated bisphenol A and thus increasing product purity. When the copper additive content in the catalyst reaches about 0.8%, the hydrogenation reaction is basically saturated, and the product selectivity and purity reach their highest levels.

[0042] The temperature and pressure of the hydrogenation reaction mainly affect the purity of the hydrogenation product. Too high a temperature and pressure will lead to the formation of by-products, while too low a temperature and pressure will lead to incomplete reaction and insufficient product purity. Overall, the reaction effect is relatively good when the reaction temperature is around 175℃ and the pressure is around 8 MPa.

[0043] Low concentrations of bisphenol A (BPA) solution result in good reaction performance, but also lower equipment and reaction utilization, leading to relatively high costs. Considering both reaction performance and cost, a BPA solution concentration of around 25% is suitable. The same principle applies to conditions such as the hydrogen:BPA ratio and the recycle ratio; the optimal conditions are a hydrogen:BPA (mol ratio) of 25% and a recycle ratio (return volume) of approximately 20%. Liquid hourly space velocity (LHSV) represents the catalyst's ability to process the reaction liquid per hour. A LHSV of 2.5 h⁻¹ is considered optimal. -1 At around 1000 rpm, the catalyst's ability to process the reaction liquid per hour basically reaches its limit.

[0044] Considering both cost and product quality factors, the hydrogenation reaction conditions in Example 9 are the most suitable.

[0045] Examples 17-28 The hydrogenation reaction was carried out according to the process conditions of Example 9 in the above implementation method, and the hydrogenation reaction product was purified by sequentially performing atmospheric pressure solvent removal, vacuum desorption of light components in a scraped film evaporator, and desorption of heavy components in a molecular distillation column. The effect of product purification under different process conditions was investigated, and the hydrogenated bisphenol A tablets were analyzed. The specific implementation conditions and analysis data are shown in Table 2. Table 2 Product Refinement and Data Analysis Table

[0046] The product refining process plays an indispensable role in improving product selectivity and purity, as well as increasing the content of trans / trans isomers. Atmospheric flash evaporators distill off the solvent isopropanol, allowing for reuse. Lower temperatures can lead to isopropanol contamination and reduced product purity. Product quality is better at temperatures of 105 °C and above. Scraped film evaporators remove light components by lowering the boiling point through decompression. Increased temperature or decreased pressure causes lighter components with boiling points lower than the product to be distilled off. As shown in the table, product purity remains essentially unchanged at temperatures between 200-210 °C; further increases in temperature have little effect and may even increase costs. Product purity and trans / trans isomer content also reach their peak at a pressure of -0.09 MPa. Molecular distillation columns significantly reduce the boiling point of products by applying absolute pressure, thereby separating the products from the deweighted components (those with boiling points higher than the product's boiling point). The absolute pressure in molecular distillation has a significant impact on product quality. When the absolute pressure is below 4 Pa, the product purity is relatively high, with around 2 Pa being the most suitable. Further reducing the absolute pressure does not significantly improve product quality and will increase costs.

[0047] Based on the above data analysis, the product refining process plays a crucial role in improving the selectivity and purity of the product and increasing the content of trans / trans isomers.

[0048] Comparative Examples 1-4 The catalyst conditions were changed: Comparative Example 1 did not add the active ingredient iridium, Comparative Example 2 did not add the catalyst promoter Cu, and Comparative Examples 3 and 4 had different supports. Experiments were conducted according to the hydrogenation reaction conditions in Example 9. The analysis results and comparisons of the reaction products are shown in Table 3.

[0049] Table 3 Comparative Data Analysis Table

[0050] The comparison between the examples and comparative examples shows that the addition of the iridium-based catalyst significantly improves the overall catalyst activity, greatly contributing to the purity and trans / trans isomer content of the hydrogenated bisphenol A product. The addition of the copper promoter makes deep hydrogenation of hydrogenated bisphenol A difficult, improving the selectivity of hydrogenated bisphenol A and increasing product purity. The mesoporous composite supports of alumina and silica, combined, provide strong support for the release of catalyst activity, improving product quality.

[0051] Comparative Examples 5-7 The hydrogenation products were not returned to the tubular fixed-bed reactor 5 for liquid circulation, but were instead all extracted and directly refined. The hydrogenation reaction was carried out according to the process conditions in Examples 8, 10, and 12. The analysis results and comparison of the reaction products are shown in Table 4.

[0052] Table 4 Comparative Data Analysis Table

[0053] As can be seen from the comparison between the examples and the comparative examples, the liquid recycling of the hydrogenation product improves the purity of the product and significantly increases the proportion of trans / trans isomers in the hydrogenation product, playing a key role in increasing the content of trans / trans isomers.

[0054] Comparative Examples 8-13 In this example, the conditions in the product refining process were changed, and compared with Examples 23, 25, and 26. The reaction product analysis results and comparison are shown in Table 5.

[0055] Table 5. Comparative Data Analysis Table

[0056] As can be seen from the comparison of the examples and comparative examples, the existence of the product refining process plays a crucial role in improving product quality. The scraped film evaporator removes light component impurities, and molecular distillation removes heavy component impurities. The organic combination of the two improves the purity of hydrogenated bisphenol A product and increases the content of trans / trans isomers.

[0057] Conclusion: The addition of iridium to the nickel-based catalyst significantly enhances the overall catalyst activity, greatly improving the purity and trans / trans isomer content of hydrogenated bisphenol A. The addition of copper promoters makes deep hydrogenation of hydrogenated bisphenol A more difficult, thus improving the selectivity of hydrogenated bisphenol A. The presence of mesoporous composite supports alumina and silica, in combination, provides strong support for the release of catalyst activity. Liquid recycling of the hydrogenation product improves product purity and significantly increases the proportion of trans / trans isomers in the hydrogenation product, while eliminating the need for a hydrogen compression circulation system, greatly reducing equipment investment and energy consumption. The scraped-film evaporator removes light component impurities, and molecular distillation removes heavy component impurities; the organic combination of these two methods jointly improves the purity of the hydrogenated bisphenol A product. This results in a continuous method for the preparation of hydrogenated bisphenol A, which is feasible, easy to produce, process-controllable, and cost-effective. The catalyst prepared according to this invention and the method for preparing hydrogenated bisphenol A achieve a conversion rate of 100%, a selectivity >99%, and a product purity >99%, with the trans / trans isomer ratio reaching 65%. The above description of the embodiments and comparative examples is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. The application of a hydrogenation catalyst in the preparation of hydrogenated bisphenol A, characterized in that, The hydrogenation catalyst comprises a support, a catalyst promoter, and an active component dispersed on the support; the active component includes a first active component and a second active component; the first active component is nickel, and the second active component is iridium; the catalyst promoter is copper; the support is alumina and silicon oxide in a mass ratio of 1:1; the support has a mesoporous structure. The preparation process includes the following steps: S21: Catalyst loading and system replacement: The hydrogenation catalyst described above is loaded into the tubular fixed bed reactor (5), and the system is repeatedly flushed with nitrogen to ensure that no other impurity gases are present in the system; S22: Preparation of raw materials: Add bisphenol A and solvent and stir to dissolve, and control the mass concentration of bisphenol A to 10-30% to obtain a bisphenol A solution; S23: The prepared bisphenol A solution and high-pressure hydrogen are mixed in a tubular fixed-bed reactor (5) and hydrogenated under the action of a hydrogenation catalyst to obtain hydrogenated products; The tubular fixed bed reactor (5) is equipped with three hydrogen inlets, a, b, and c, in the middle section. High-pressure hydrogen enters the tubular fixed bed reactor (5) from the three hydrogen inlets, a, b, and c. S24: Solvent recovery: The hydrogenation product described in step S23 is cooled by the first condenser (6) and then enters the first-stage high-pressure separator (7) for gas-liquid separation. The small amount of hydrogen and vaporized solvent separated by the first-stage high-pressure separator (7) are cooled by the second condenser (8) and then enter the second-stage high-pressure separator (9) for gas-liquid separation. The small amount of hydrogen separated is released as tail gas, and the separated hydrogenation product solution enters the solvent recovery tank (10) for recycling. S25: Liquid product circulation: The hydrogenated product solution separated by the first-stage high-pressure separator (7) is analyzed by the online chromatograph (11) to determine the ratio of the returned amount to the collected amount. The returned part is metered and pressurized by the third metering pump (12) and returned to the tubular fixed bed reactor (5) for hydrogenation reaction again. The collected part is the crude hydrogenated bisphenol A. The crude hydrogenated bisphenol A is metered into the crude product tank (14) by the fourth metering pump (13). S26: Product Refining: The crude hydrogenated bisphenol A in the crude product tank (14) is then passed through the fifth metering pump (15) and the first preheater (4) and enters the atmospheric pressure flash evaporator (17) for atmospheric pressure desolventizing. The desolventized gaseous solvent is cooled by the third condenser (18) and then enters the solvent recovery tank (10) for recycling. The remaining liquid solution enters the scraped film evaporator (19) for desolventizing and removing by-products under reduced pressure. The upper part of the scraped film evaporator (19) discharges light component impurities, and the lower part yields hydrogenated bisphenol A product with relatively high purity. The hydrogenated bisphenol A product with relatively high purity enters the molecular distillation column (20) for further refining. The bottom of the molecular distillation column (20) discharges heavy component impurities, and the molecular distillation column (20) yields hydrogenated bisphenol A product with high purity. The tubular fixed-bed reactor (5) operates at a temperature of 150–200 °C, a pressure of 6–9 MPa, and a liquid hourly space velocity of 2–4 h⁻¹. -1 In mol, the ratio of hydrogen to BPA is 10-30:1; the operating temperature of the preheater (4) is 80-100 ℃; the operating temperature of the atmospheric flash evaporator (17) is 80-120 ℃ and the pressure is atmospheric; the operating temperature of the scraped film evaporator (19) is 180-220 ℃ and the pressure is -0.08 to -0.1 MPa.

2. The application according to claim 1, characterized in that, The preparation method of the hydrogenation catalyst includes the following steps: S11: Carrier preparation: A diblock polymeric surfactant is added to an acid solution and stirred. The molar ratio of the diblock polymeric surfactant to the acid is 1:1500-60000. After it is completely dissolved, the carrier is added. Stirring continues until a precipitate is formed. The reaction solution and precipitate are transferred to a hydrothermal reactor and allowed to stand and cool. Then, the solution is filtered, washed, and dried. The mixture is calcined once to obtain a powdered mesoporous carrier material. S12: Carrier impregnation: Prepare an aqueous solution of nickel and iridium in hydrochloric acid to form an active component solution; impregnate the catalyst and the mesoporous carrier material prepared in step S11 into the active component solution, so that the active component is uniformly attached to the carrier, and the impregnated carrier is obtained. S13: Preparation of hydrogenation catalyst: The support impregnated in step S12 is dried and then calcined twice to obtain the hydrogenation catalyst.

3. The application according to claim 2, characterized in that, The acid solution in step S11 is one or more of hydrochloric acid, sulfuric acid, or nitric acid; the molar ratio of the carrier to the surfactant is 240-5000:1; the standing is specifically at 80-150℃ for 8-24 h; the first calcination is specifically at 450-650℃ for 4-6 h.

4. The application according to claim 2, characterized in that, The hydrochloric acid aqueous solution of nickel and iridium mentioned in step S12 is specifically a 20-30 wt% nickel chloride and a 0.3-1.0 wt% iridium chloride aqueous solution; the catalyst is prepared by mixing copper chromite and hydrochloric acid solution in a mass ratio of 1:3, with an addition amount of 0.5-1.0 wt% copper chromite solution.

5. The application according to claim 2, characterized in that, The soaking time in step S12 is 1-10 h.

6. The application according to claim 2, characterized in that, The drying in step S13 is performed at 100-120 ℃ for 2-12 hours; the secondary calcination is performed at 500-700 ℃ for 5-12 hours.

7. The application according to claim 1, characterized in that, The hydrogenation catalyst in the tubular fixed-bed hydrogenation reactor tubes mentioned in step S21 is packed in a random manner, and the ratio of the height to the diameter of the fixed-bed reactor tubes is 3-10:1; the solvent mentioned in step S22 is one of ethanol, propanol, isopropanol or cyclohexane.

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