Preparation method and application of hydrophobic alumina catalyst for high-efficiency synthesis of bisphenol a

Abstract

The application discloses a preparation method and application of a hydrophobic alumina catalyst for efficiently synthesizing bisphenol A. The preparation method of the catalyst comprises two steps of sulfonation modification and N,N-dimethyl-heptane thioamide hydrophobic modification. The catalyst is applied to a process of preparing bisphenol A through condensation reaction of phenol and acetone, and has the advantages of high reaction efficiency, high conversion rate and high selectivity, and is favorable for improving product yield.

Description

Technical Field

[0001] This invention relates to a bisphenol A catalyst, and more particularly to a method for preparing and applying a highly efficient hydrophobic alumina catalyst for the synthesis of bisphenol A. Background Technology

[0002] Bisphenol A (BPA) is an important organic chemical raw material, mainly used in the production of various polymer materials such as polycarbonate, epoxy resin, and polysulfone resin. It can also be used in the production of fine chemical products such as plasticizers and flame retardants, and is widely used in industrial, construction, medical and other fields.

[0003] The industrial production of bisphenol A generally uses phenol and acetone as raw materials, which are obtained through a condensation reaction in the presence of an acidic catalyst (such as an ion exchange resin), as described in patents WO2022179902A1 and CN112279751B. The reaction mechanism involves acetone first forming a carbocation to alkylate phenol, which then condenses under acidic conditions to form bisphenol A.

[0004] In the condensation reaction of phenol and acetone to produce bisphenol A, the water produced can destroy the active sites of the catalyst, thereby reducing the number of active sites and severely hindering the reaction. Simultaneously, the presence of water affects the adsorption of phenol and acetone by the ion exchange resin, influencing the reaction equilibrium rate and leading to a lower yield of bisphenol A. For example, Jerabek et al. reported that when the water concentration in the reaction system increased from 100 mol / m³, the yield of bisphenol A decreased. 3 Increase to 1 kmol / m 3 The condensation reaction rate can decrease by tens of times (DOI:10.1016 / S0166-9834(00)80756-3).

[0005] To address the aforementioned issues, existing processes reduce the water content at the reactor inlet by decreasing the water content in the mother liquor. However, this has no effect on the water content generated during the reaction process, which still slows down the reaction.

[0006] In addition, phenol and acetone undergo a condensation reaction under acidic conditions to form bisphenol A. Even in the presence of strong acid, the condensation reaction rate is very slow. The reason for this is that the formation of carbocations by acetone slows down the alkylation process of phenol.

[0007] Patent CN107876089B discloses an ionic liquid catalyst system for the synthesis of bisphenol A and its preparation method. It uses a homogeneous catalyst to accelerate the condensation reaction in the synthesis of bisphenol A, improves the conversion rate of acetone and the selectivity of bisphenol A. However, the test results show that the catalytic performance of the catalyst system is still limited, and the recovery of ionic liquid catalyst is difficult, which will increase the complexity of subsequent separation processes and energy consumption. Summary of the Invention

[0008] To address the aforementioned technical problems, this invention first proposes a method for preparing a highly efficient hydrophobic alumina catalyst for the synthesis of bisphenol A. After obtaining the alumina catalyst through sulfonation modification, this invention further modifies it with N,N-dimethyl-heptanethioamide, which has a hydrophobic long alkyl chain and a thioamide group. On the one hand, the introduction of hydrophobic groups allows water generated during the reaction to rapidly escape from the catalyst's active sites, increasing the acetone conversion rate. On the other hand, the introduction of thioamide effectively increases the rate of acetone carbocation formation, solving the problem of the rate-limiting effect of acetone carbocation formation. Furthermore, the L-acid of the alumina and the Brønsted acid of the sulfonic acid group produce a synergistic effect, enhancing acid strength, stability, and catalytic activity, greatly improving the BPA yield.

[0009] The present invention also proposes a highly efficient method for synthesizing bisphenol A. This method involves the condensation reaction of phenol and acetone in the presence of the aforementioned hydrophobic alumina catalyst. This method has the advantages of high reaction efficiency, high conversion rate and high selectivity, which is beneficial to improving product yield.

[0010] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0011] A method for preparing a highly efficient hydrophobic alumina catalyst for the synthesis of bisphenol A includes the following steps:

[0012] S1, Sulfonation Modification

[0013] After sequentially acid washing and water washing, the macroporous alumina microspheres were dried; then impregnated with sulfuric acid, dried, and calcined to obtain sulfonated modified macroporous alumina microspheres.

[0014] S2, hydrophobic modification

[0015] Prepare an N,N-dimethyl-heptanethioamide solution with a mass concentration of 0.1-1.5 mol / L, and mix it with the sulfonated modified macroporous alumina microspheres obtained in step S1 in equal volume. Mix at 30-60℃ for 2-5 h, then let stand for 4-14 h, and then dry at 110-120℃, preferably for 20-30 h, to obtain a hydrophobic alumina catalyst.

[0016] In traditional catalysts for the synthesis of bisphenol A, the catalytic activity is mainly driven by the Brønsted acid (B) acid active center. This invention utilizes sulfonic acid-modified macroporous alumina microspheres to combine Brønsted and Lewis acids, forming new acid centers. This increases the acid content and strength of the catalyst, enhances catalytic activity, and avoids the formation of H+ ions. +Deactivated by metal ion exchange, its stability and lifespan are also improved. On the other hand, the amino group of N,N-dimethyl-heptanethioamide reacts with the sulfonic acid group of macroporous alumina microspheres to form an ionic bond between the two groups. Introducing N,N-dimethyl-heptanethioamide carrying hydrophobic groups can rapidly remove the water produced in the reaction from the active site of the catalyst, improving the acetone conversion rate. The introduction of thioamide allows for nucleophilic addition reaction with acetone under acidic conditions to generate a hemiketal intermediate, which then dehydrates to form a carbocation, accelerating the formation of the carbocation from acetone and thus speeding up the reaction process.

[0017] As a preferred embodiment, in step S1, the pickling process involves washing with 0.1-1.0 mol / L hydrochloric acid at a volume 2-4 times that of the macroporous alumina microspheres for 2-10 minutes.

[0018] As a preferred embodiment, in step S1, after pickling, the surface is washed with water until neutral, and then dried at 100-130℃ for 1-5 hours.

[0019] As a preferred embodiment, the macroporous alumina microspheres have a particle size of 0.5-3 mm and a pore size of 10-100 nm.

[0020] As a preferred embodiment, in step S1, the sulfuric acid impregnation uses 0.1-0.7 mol / L sulfuric acid, and the impregnation amount is 0.1-2.0 mL of impregnation solution per gram of macroporous alumina microspheres;

[0021] As a preferred embodiment, in step S1, the sulfuric acid immersion conditions are: immersion at 50-150℃ for 10-30 hours.

[0022] As a preferred embodiment, in step S1, after sulfuric acid impregnation, the product is dried at 90-130°C for 1-5 hours, and then calcined at 200-600°C for 1-5 hours.

[0023] As a preferred embodiment, in step S2, after impregnation, the product is dried at 90-120°C for 10-20 hours.

[0024] A highly efficient method for synthesizing bisphenol A involves reacting phenol with acetone in the presence of a hydrophobic alumina catalyst described above to produce bisphenol A.

[0025] As a preferred embodiment, the condensation reaction temperature is 70-80℃ and the reaction pressure is 0.3-0.9 MPa;

[0026] Preferably, the phenol feed space velocity is 0.2-1 h. -1 ;

[0027] Preferably, the molar ratio of phenol to acetone is 7-13:1.

[0028] The synthesis of bisphenol A using the hydrophobic alumina catalyst provided by this invention has the advantages of high reaction efficiency, high conversion and selectivity, and good catalyst stability. Detailed Implementation

[0029] The present invention will be further illustrated below with specific embodiments. These embodiments are merely illustrative and do not limit the scope of the invention.

[0030] Unless otherwise specified, all raw materials and reagents used in the following embodiments and comparative examples of this invention were purchased from commercially available finished products. N,N-dimethylheptanethioamide (CAS: 133896-91-0) was purchased from Hangzhou Taorui Biotechnology Co., Ltd.

[0031] The product testing method used in the following embodiments and comparative examples of this invention is liquid chromatography, and the equipment used is LC-D100, Thermo Fisher Scientific (China) Co., Ltd.

[0032] Unless otherwise specified, all pressures mentioned in this invention refer to gauge pressure.

[0033]

Example 1

[0034] Hydrophobic alumina catalyst A was prepared according to the following method:

[0035] S1, Sulfonation Modification

[0036] 1 g of macroporous alumina microspheres (particle size 0.5-1.2 mm) were washed with 0.1 mol / L hydrochloric acid for 5 min, with the amount of hydrochloric acid being twice the volume of the macroporous alumina microspheres; then washed with water until neutral, and dried at 110 °C for 2 h. Next, they were immersed in 2.0 mL of 0.3 mol / L sulfuric acid at 100 °C for 24 h, dried at 110 °C for 2 h, and then calcined at 450 °C for 3 h to obtain sulfonated modified macroporous alumina microspheres.

[0037] S2, hydrophobic modification

[0038] A 0.2 mol / L N,N-dimethyl-heptanethioamide solution was prepared and mixed with the sulfonated modified macroporous alumina microspheres obtained in step S1 in a cone mixer in equal volume. The mixture was mixed at 40°C for 2 h, then allowed to stand for 8 h, and then dried at 110°C for 20 h to obtain hydrophobic alumina catalyst A.

[0039]

Example 2

[0040] Hydrophobic alumina catalyst B was prepared according to the following method:

[0041] S1, Sulfonation Modification

[0042] 1 g of macroporous alumina microspheres (particle size 0.5-1.2 mm) were washed with 0.2 mol / L hydrochloric acid for 2 min, with the amount of hydrochloric acid being 3 times the volume of the macroporous alumina microspheres; then washed with water until neutral, and dried at 115 °C for 1 h. Next, they were immersed in 0.1 mL of 0.1 mol / L sulfuric acid at 50 °C for 10 h, dried at 90 °C for 1 h, and then calcined at 200 °C for 1 h to obtain sulfonated modified macroporous alumina microspheres.

[0043] S2, hydrophobic modification

[0044] A 0.1 mol / L N,N-dimethyl-heptanethioamide solution was prepared and mixed in equal volume with the sulfonated modified macroporous alumina microspheres obtained in step S1 in a cone mixer. The mixture was mixed at 30°C for 5 h, then allowed to stand for 14 h, and then dried at 120°C for 30 h to obtain hydrophobic alumina catalyst B.

[0045]

Example 3

[0046] Hydrophobic alumina catalyst C was prepared according to the following method:

[0047] S1, Sulfonation Modification

[0048] 1 g of macroporous alumina microspheres (particle size 0.5-1.2 mm) were washed with 0.6 mol / L hydrochloric acid for 7 min, with the amount of hydrochloric acid being twice the volume of the macroporous alumina microspheres. They were then washed with water until neutral and dried at 120 °C for 3 h. Next, they were immersed in 0.7 mL of 0.5 mol / L sulfuric acid at 70 °C for 30 h, dried at 130 °C for 1.5 h, and then calcined at 300 °C for 5 h to obtain sulfonated modified macroporous alumina microspheres.

[0049] S2, hydrophobic modification

[0050] A 1.5 mol / L N,N-dimethyl-heptanethioamide solution was prepared and mixed with the sulfonated modified macroporous alumina microspheres obtained in step S1 in a cone mixer in equal volume. The mixture was mixed at 60 °C for 3 h, then allowed to stand for 10 h, and then dried at 115 °C for 22 h to obtain hydrophobic alumina catalyst C.

[0051]

Example 4

[0052] Hydrophobic alumina catalyst D was prepared according to the following method:

[0053] S1, Sulfonation Modification

[0054] 1 g of macroporous alumina microspheres (particle size 0.5-1.2 mm) were washed with 0.8 mol / L hydrochloric acid for 9 min, with the amount of hydrochloric acid being twice the volume of the macroporous alumina microspheres. They were then washed with water until neutral and dried at 125 °C for 4 h. Next, they were immersed in 1.5 mL of 0.5 mol / L sulfuric acid at 120 °C for 16 h, dried at 120 °C for 5 h, and then calcined at 600 °C for 2 h to obtain sulfonated modified macroporous alumina microspheres.

[0055] S2, hydrophobic modification

[0056] A 1.0 mol / L N,N-dimethyl-heptanethioamide solution was prepared and mixed in equal volume with the sulfonated modified macroporous alumina microspheres obtained in step S1 in a cone mixer. The mixture was mixed at 51 °C for 4 h, allowed to stand for 13 h, and then dried at 116 °C for 25 h to obtain hydrophobic alumina catalyst D.

[0057]

Example 5

[0058] Hydrophobic alumina catalyst E was prepared according to the following method:

[0059] S1, Sulfonation Modification

[0060] 1 g of macroporous alumina microspheres (particle size 0.5-1.2 mm) were washed with 1.0 mol / L hydrochloric acid for 10 min, with the amount of hydrochloric acid being 4 times the volume of the macroporous alumina microspheres. They were then washed with water until neutral and dried at 130 °C for 5 h. Next, they were immersed in 1.7 mL of 0.4 mol / L sulfuric acid at 150 °C for 27 h, dried at 115 °C for 3.5 h, and then calcined at 500 °C for 4 h to obtain sulfonated modified macroporous alumina microspheres.

[0061] S2, hydrophobic modification

[0062] A 0.8 mol / L N,N-dimethyl-heptanethioamide solution was prepared and mixed in equal volume with the sulfonated modified macroporous alumina microspheres obtained in step S1 in a cone mixer. The mixture was mixed at 35°C for 2.5 h, allowed to stand for 12 h, and then dried at 117°C for 27 h to obtain hydrophobic alumina catalyst E.

[0063] Comparative Example 1

[0064] A hydrophobic alumina catalyst, denoted as catalyst F, was prepared using essentially the same method as in Example 1, except that sulfuric acid impregnation was not performed in step S1.

[0065] Comparative Example 2

[0066] An alumina catalyst, denoted as catalyst G, was prepared using a method essentially the same as in Example 1, except that the operation in step S2 was omitted; that is, the sulfonated modified macroporous alumina microspheres obtained in step S1 were directly used as catalyst G.

[0067] Comparative Example 3

[0068] An alumina catalyst, denoted as catalyst H, was prepared using essentially the same method as in Example 1, except that N,N-dimethyl-heptanethioamide in step S2 was replaced with 2,2-dimethylthiazolidinyl.

[0069]

Application Example 1

[0070] The alumina catalysts prepared in Examples 1-5 and Comparative Examples 1-3 were used to carry out the synthesis reaction of bisphenol A, respectively, under the following reaction conditions:

[0071] The catalyst was loaded into a fixed-bed condensation catalytic reactor. Soluble impurities in the catalyst were washed with pure water, and the water in the catalyst was replaced with phenol. Then, phenol and acetone were fed at a molar ratio of 9:1, with a feed space velocity of 0.2 h⁻¹ for phenol. -1 The reaction temperature was 80℃ and the reaction pressure was 0.3 MPa.

[0072] The catalytic effects of each catalyst are shown in Table 1:

[0073] Table 1. Comparison of catalytic effects

[0074] Conversion rate / % Selectivity / % Yield / % Catalyst A 83.5％ 94.7％ 79.1％ Catalyst B 83.3％ 94.5％ 78.7％ Catalyst C 85.3％ 96.5％ 82.3％ Catalyst D 84.3％ 96.1％ 81.0％ Catalyst E 84.1％ 95.9％ 80.7％ Catalyst F 69.3％ 83.5％ 57.9％ Catalyst G 72.3％ 86.1％ 62.3％ catalyst H 71.5％ 87.3％ 62.4％

[0075] Then, catalyst recycling experiments were conducted on catalysts A and F to test the product yield at different recycling times. The results are shown in Table 2.

[0076] Table 2. Results of the Cyclic Application Test

[0077] 10 times 20 times 30 times 40 times 50 times Catalyst A 79.1％ 78.9％ 78.9％ 78.8％ 78.7％ Catalyst F 57.9％ 55.2％ 50.6％ 42.3％ 30.1％

[0078]

Application Example 2

[0079] The alumina catalysts prepared in Examples 1 and Comparative Examples 1-3 were used to carry out the synthesis reaction of bisphenol A, and the reaction conditions were as follows:

[0080] The catalyst was loaded into a fixed-bed condensation catalytic reactor. Soluble impurities in the catalyst were washed with pure water, and the water in the catalyst was replaced with phenol. Phenol and acetone were then fed at a molar ratio of 9:1, with a feed space velocity of 0.15 h⁻¹ for phenol. -1 The reaction temperature was 80℃ and the reaction pressure was 0.3 MPa.

[0081] The catalytic effects of each catalyst are shown in Table 3:

[0082] Table 3. Comparison of catalytic effects

[0083] Conversion rate / % Selectivity / % Yield / % Catalyst A 83.1％ 94.3％ 78.8％ Catalyst F 75.3％ 88.6％ 67.1％ Catalyst G 77.3％ 89.1％ 67.8％ catalyst H 76.9％ 89.5％ 67.3％

[0084] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several 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.

Claims

1. A method for preparing a highly efficient hydrophobic alumina catalyst for the synthesis of bisphenol A, characterized in that, Includes the following steps: S1, Sulfonation modification: Macroporous alumina microspheres were sequentially acid-washed, water-washed, and dried; then impregnated with sulfuric acid, dried, and calcined to obtain sulfonated modified macroporous alumina microspheres; the particle size of the macroporous alumina microspheres was 0.5-3 mm, and the pore size was 10-100 nm; the sulfuric acid impregnation used 0.1-0.7 mol / L sulfuric acid, and the impregnation amount was 0.1-2.0 mL of impregnation solution per gram of macroporous alumina microspheres; S2, hydrophobic modification: Prepare an N,N-dimethyl-heptanethioamide solution with a mass concentration of 0.1-1.5 mol / L, and impregnate it with the sulfonated modified macroporous alumina microspheres obtained in step S1 in equal volume. Mix at 30-60℃ for 2-5 h, let stand for 4-14 h, and then dry at 110-120℃ to obtain a hydrophobic alumina catalyst.

2. The method for preparing the highly efficient hydrophobic alumina catalyst for the synthesis of bisphenol A according to claim 1, characterized in that, In step S1, during the pickling process, use 0.1-1.0 mol / L hydrochloric acid with a volume of 2-4 times that of the macroporous alumina microspheres for 2-10 min.

3. The method for preparing the highly efficient hydrophobic alumina catalyst for the synthesis of bisphenol A according to claim 2, characterized in that, In step S1, after pickling, the surface is washed with water until neutral and then dried at 100-130℃ for 1-5 hours.

4. The method for preparing the highly efficient hydrophobic alumina catalyst for the synthesis of bisphenol A according to claim 1, characterized in that, In step S1, the sulfuric acid immersion conditions are: immersion at 50-150℃ for 10-30 hours.

5. The method for preparing the highly efficient hydrophobic alumina catalyst for the synthesis of bisphenol A according to claim 4, characterized in that, In step S1, after sulfuric acid impregnation, the product is dried at 90-130℃ for 1-5 hours, and then calcined at 200-600℃ for 1-5 hours.

6. The method for preparing the highly efficient hydrophobic alumina catalyst for the synthesis of bisphenol A according to any one of claims 1-3, characterized in that, In step S2, after impregnation, dry at 90-120℃ for 10-20 hours.

7. A method for the efficient synthesis of bisphenol A, characterized in that, In the presence of the catalyst prepared by the method for preparing the highly efficient hydrophobic alumina catalyst for the synthesis of bisphenol A according to any one of claims 1-6, phenol and acetone are subjected to a condensation reaction to obtain bisphenol A.

8. The efficient method for synthesizing bisphenol A according to claim 7, characterized in that, The condensation reaction temperature is 70-80℃, and the reaction pressure is 0.3-0.9MPa.

9. The efficient method for synthesizing bisphenol A according to claim 8, characterized in that, The phenol feed space velocity is 0.2-1 h⁻¹. -1 .

10. The efficient method for synthesizing bisphenol A according to claim 8, characterized in that, The molar ratio of phenol to acetone is 7-13:1.