Cyclohexanone catalyst prepared by phenol hydrogenation and preparation method thereof

Abstract

The invention relates to the technical field of catalyst preparation, in particular to a cyclohexanone catalyst prepared through phenol hydrogenation and a preparation method of the cyclohexanone catalyst. The catalyst is prepared from the following raw materials in parts by weight: 60 to 70 parts of gamma-aluminum oxide, 0.5 to 1.5 parts of modified polyethylene glycol, 0.3 to 0.8 part of modified hexadecyl trimethyl ammonium bromide, 1.5 to 2.5 parts of palladium acetate, 5 to 10 parts of ammonia water with the concentration of 25 percent, 100 to 120 parts of ethanol, 5 to 10 parts of modified sesbania powder and 5 to 8 parts of tetraethoxysilane. By adding the modified sesbania powder, the carbon deposition rate of the catalyst can be reduced, and the service life of the catalyst can be prolonged; by adding the modified polyethylene glycol, the hydrophobicity of the catalyst can be reduced, excessive retention of cyclohexanone on the surface is avoided, the selectivity of cyclohexanone is improved, and the stability of the catalyst can be improved by cooperating with the modified sesbania powder; and by adding the modified hexadecyl trimethyl ammonium bromide, the uniform distribution of the Pd active component can be improved.

Description

Technical Field

[0001] This invention relates to the field of catalyst preparation technology, specifically to a catalyst for the hydrogenation of phenol to cyclohexanone and its preparation method. Background Technology

[0002] The catalyst for the hydrogenation of phenol to cyclohexanone is the key material for realizing this reaction. Its core role is to promote the addition reaction between the benzene ring in the phenol molecule and hydrogen gas, while inhibiting the formation of by-products (such as cyclohexanol and cyclohexane), thereby efficiently producing cyclohexanone.

[0003] The core challenges of existing catalysts are: the contradiction between cost and stability of precious metal catalysts, the insufficient activity and selectivity of non-precious metal catalysts, and the problems of low regeneration efficiency and high environmental risk faced by all types of catalysts. Summary of the Invention

[0004] The purpose of this invention is to provide a catalyst for the hydrogenation of phenol to cyclohexanone and a method for its preparation. The catalyst for the hydrogenation of phenol to cyclohexanone prepared by this invention not only has good activity and improves the catalytic ability of the catalyst, but also inhibits the excessive hydrogenation of cyclohexanone and reduces material waste.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a catalyst for the hydrogenation of phenol to cyclohexanone, comprising the following raw materials in parts by weight: 60-70 parts γ-alumina, 0.5-1.5 parts modified polyethylene glycol, 0.3-0.8 parts modified hexadecyltrimethylammonium bromide, 1.5-2.5 parts palladium acetate, 5-10 parts 25% ammonia water, 100-120 parts ethanol, 5-10 parts modified guar gum powder, and 5-8 parts tetraethyl orthosilicate; The preparation of the catalyst for the hydrogenation of phenol to cyclohexanone includes the following steps: S1. Place γ-alumina in a muffle furnace and calcine it at 5℃ / min to 550℃, hold it at that temperature for 4 hours to obtain dry γ-alumina; add modified guar gum powder and dry γ-alumina into a reaction vessel, add ethanol accounting for 5% of the total ethanol and knead to obtain a moist composite carrier; place the moist composite carrier in a drying oven and dry it at 110℃ for 4 hours, then calcine it in a muffle furnace at 300℃ for 2 hours to obtain the composite carrier; S2. Add the composite carrier and 40% ethanol (based on the total ethanol content) to a reaction vessel and stir at 200-300 rpm for 15-30 minutes to obtain a composite carrier solution. Dissolve tetraethyl orthosilicate in 20% ethanol (based on the total ethanol content) to obtain a tetraethyl orthosilicate solution. Add the composite carrier solution to a water bath reaction vessel, add the tetraethyl orthosilicate solution and stir at 200-300 rpm for 10-15 minutes. Add 25% ammonia solution and stir at 60℃ for 400-600 rpm for 2-3 hours to obtain a modified composite solution. S3. Dissolve palladium acetate in ethanol accounting for 30% of the total ethanol content, add modified hexadecyltrimethylammonium bromide and modified polyethylene glycol, stir at 300-400 rpm for 15-30 minutes, add the modified composite solution, stir at 100-200 rpm for 12 hours, add ethanol accounting for 5% of the total ethanol content, heat to 60℃, purge with a mixed gas of hydrogen and nitrogen, hydrogen concentration 10%, purge with a mixed gas flow rate of 50 mL / min for 2 hours, filter out the filtrate, and dry the remaining solid in a drying oven at 100℃ for 6 hours to obtain the dried catalyst; S4. Grind the dried catalyst into powder, place the powder in a tube furnace for calcination, introduce nitrogen gas, heat to 300-400℃ at a heating rate of 5℃ / min, and hold for 2 hours to obtain the catalyst for the hydrogenation of phenol to cyclohexanone.

[0006] Furthermore, the pH value is adjusted to 8-9 by adding ammonia. The hydrogen concentration in S3 is 10%; The dried catalyst in S4 is ground to 80-150 mesh.

[0007] Furthermore, the modified polyethylene glycol comprises the following components: 95-105 parts polyethylene glycol, 55-65 parts ethylenediamine, and 1-2 parts sodium methoxide.

[0008] Furthermore, the preparation of the modified polyethylene glycol includes the following steps: Step 1. Connect the reactor to the rotary evaporator, add polyethylene glycol to the reactor, control the temperature at 60℃ and the pressure at -0.09MPa, and rotary evaporate for 1-2 hours to obtain dried polyethylene glycol; Step 2. Dry ethylenediamine using 4A molecular sieve for 24 hours to obtain dried ethylenediamine; Step 3. Add dried polyethylene glycol to the reaction vessel, purge with nitrogen gas at a flow rate of 50 mL / min for 30 minutes, add sodium methoxide and stir at a speed of 400-500 rpm, heat to 60℃ and stir for 20 minutes, add dried ethylenediamine dropwise at a rate of 1 drop / second, stir after all has been added, maintain the temperature at 80℃ and the speed at 350-400 rpm for 5 hours to obtain a mixed polyethylene glycol solvent; Step 4. Cool the polyethylene glycol mixed solvent to 18-25℃, add deionized water, stir for 10 minutes, add hydrochloric acid, and extract with dichloromethane using a separatory funnel to obtain the organic phase. Dry the organic phase with anhydrous sodium sulfate for 2 hours, filter out the anhydrous sodium sulfate, and evaporate using a rotary evaporator at 40℃ and -0.09MPa to obtain the crude product. Add the crude product and ethanol to a reaction vessel and stir magnetically at 300-400 rpm at 60-70℃ for 5-10 minutes. Cool to 20-25℃. The reaction vessel was placed in a water bath at 0-4℃ and allowed to stand for 1-2 hours to obtain white crystals. The white crystals were washed with anhydrous ethanol. The washed white crystals and ethanol were added to the reaction vessel. The stirring speed was 300-400 rpm and the temperature was controlled at 55-65℃. The mixture was stirred for 5-10 minutes and cooled to 20-25℃. The reaction vessel was then placed in a water bath at 0-4℃ and allowed to stand for 1-2 hours to obtain pure crystals. The pure crystals were then placed in a vacuum drying oven at 60℃ and -0.09MPa for 8 hours to obtain modified polyethylene glycol.

[0009] Furthermore, in step four, the mass ratio of dichloromethane to deionized water is 1:1; The mass ratio of tetrachloromethane to polyethylene glycol is 1:1.

[0010] Furthermore, the mass ratio of the crude product to ethanol in step four is 1:3; The mass ratio of white crystals to anhydrous ethanol is 1:3.

[0011] Further, the preparation of the modified guar gum powder includes the following steps: adding guar gum powder, sodium chloride and deionized water into a water bath reactor and stirring at 200-400 rpm and 40-50°C for 1-2 hours to obtain a guar gum powder emulsion; adding sodium hydroxide solution to the guar gum powder emulsion to adjust the pH value; adding sodium trimetaphosphate and stirring for 1-2 hours; adding dilute hydrochloric acid to adjust the pH value; filtering out the water; washing the remaining solid with deionized water; placing the solid in a drying oven to dry at 60-70°C for 6-12 hours; and grinding the dried solid to 80-120 mesh using a grinder to obtain the modified guar gum powder.

[0012] Furthermore, the mass ratio of the guar gum powder, sodium trimetaphosphate, and sodium chloride is 1:0.01-0.02:0.01-0.05; Sodium hydroxide solution was added to the guar gum emulsion to adjust the pH to 9-11; Adjust the pH to 6-7 with dilute hydrochloric acid.

[0013] Further, the preparation of the modified hexadecyltrimethylammonium bromide includes the following steps: adding hexadecyltrimethylammonium bromide and deionized water into a reaction vessel and stirring at 200 rpm for 30 minutes; adding potassium persulfate and stirring for 10 minutes; adding sodium hydroxide and stirring; heating the temperature to 40-60℃ and stirring at 300 rpm for 1-3 hours; cooling to 18-25℃; adding sodium sulfite and stirring for 10 minutes; adding deionized water and dialyzing using a dialysis bag for 24 hours, changing the deionized water every 6 hours; evaporating the dialyzed solution on a rotary evaporator at 40℃ and 0.08 MPa for 1-1.5 hours; and drying in a vacuum drying oven at 40℃ for 12 hours to obtain the modified hexadecyltrimethylammonium bromide.

[0014] Furthermore, the mass ratio of hexadecyltrimethylammonium bromide and deionized water added to the reactor is 1:27.5; The molar ratio of hexadecyltrimethylammonium bromide to potassium persulfate is 1:0.3; The molar ratio of sodium sulfite to potassium persulfate is 1.1:1; Add sodium hydroxide to adjust the pH to 5.8-6.2.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. By adding modified guar gum powder, this invention can improve the compressive strength and wear resistance of the catalyst, reduce the aggregation of Pd active sites, and lower the carbon deposition rate of the catalyst. Modified guar gum powder can also maintain the overall structural integrity of the catalyst for a long time, avoiding the reduction of active site exposure due to support breakage. Modified guar gum powder can be completely decomposed during high-temperature calcination without residual impurities, ensuring that the activity of Pd nanoparticles is not affected.

[0016] 2. The addition of modified polyethylene glycol in this invention can improve the dispersibility of Pd²⁺, avoid the aggregation of Pd²⁺ into large particles during the preparation process, and reduce the hydrophobicity of the catalyst by the surface hydrophilicity of modified polyethylene glycol to avoid excessive retention of cyclohexanone on the surface and improve the selectivity of cyclohexanone. The synergistic effect with modified guar gum powder can further reduce the loss of Pd caused by mechanical scouring, thereby improving the stability of the catalyst.

[0017] 3. The core function of adding modified hexadecyltrimethylammonium bromide in this invention is to endow it with multiple functions through structural modification. It retains the ability to control the size of Pd particles, and enhances the synergistic effect with modified polyethylene glycol, Pd²⁺ and support through polar groups. Ultimately, it achieves high dispersion and high uniformity distribution of Pd active components, while optimizing the surface properties of the catalyst to improve the selectivity of cyclohexanone. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0019] It should be noted that the raw materials used in the following embodiments are all commercially available.

[0020] Example 1, a catalyst for the hydrogenation of phenol to cyclohexanone, is composed of the following raw materials in parts by weight: 60 parts γ-alumina, 0.5 parts modified polyethylene glycol, 0.3 parts modified hexadecyltrimethylammonium bromide, 1.5 parts palladium acetate, 5 parts 25% ammonia water, 100 parts ethanol, 5 parts modified guar gum powder and 5 parts tetraethyl orthosilicate; The preparation of the catalyst for the hydrogenation of phenol to cyclohexanone includes the following steps: S1. Place γ-alumina in a muffle furnace and calcine it at 5℃ / min to 550℃, hold it at that temperature for 4 hours to obtain dry γ-alumina; add modified guar gum powder and dry γ-alumina into a reaction vessel, add ethanol accounting for 5% of the total ethanol and knead to obtain a moist composite carrier; place the moist composite carrier in a drying oven and dry it at 110℃ for 4 hours, then calcine it in a muffle furnace at 300℃ for 2 hours to obtain the composite carrier; S2. Add the composite carrier and 40% ethanol (based on the total ethanol content) to a reaction vessel and stir at 200-300 rpm for 15-30 minutes to obtain a composite carrier solution. Dissolve tetraethyl orthosilicate in 20% ethanol (based on the total ethanol content) to obtain a tetraethyl orthosilicate solution. Add the composite carrier solution to a water bath reaction vessel, add the tetraethyl orthosilicate solution and stir at 200-300 rpm for 10-15 minutes. Add 25% ammonia solution and stir at 60℃ for 400-600 rpm for 2-3 hours to obtain a modified composite solution. S3. Dissolve palladium acetate in ethanol accounting for 30% of the total ethanol content, add modified hexadecyltrimethylammonium bromide and modified polyethylene glycol, stir at 300-400 rpm for 15-30 minutes, add the modified composite solution, stir at 100-200 rpm for 12 hours, add ethanol accounting for 5% of the total ethanol content, heat to 60℃, purge with a mixed gas of hydrogen and nitrogen, hydrogen concentration 10%, purge with a mixed gas flow rate of 50 mL / min for 2 hours, filter out the filtrate, and dry the remaining solid in a drying oven at 100℃ for 6 hours to obtain the dried catalyst; S4. Grind the dried catalyst into powder, place the powder in a tube furnace for calcination, introduce nitrogen gas, heat to 300-400℃ at a heating rate of 5℃ / min, and hold for 2 hours to obtain the catalyst for the hydrogenation of phenol to cyclohexanone.

[0021] Add ammonia to adjust the pH to 8-9; The hydrogen concentration in S3 is 10%; The dried catalyst in S4 is ground to 80-150 mesh.

[0022] Modified polyethylene glycol comprises the following components: 95-105 parts polyethylene glycol, 55-65 parts ethylenediamine, and 1-2 parts sodium methoxide.

[0023] The preparation of modified polyethylene glycol includes the following steps: Step 1. Connect the reactor to a rotary evaporator, add polyethylene glycol to the reactor, control the temperature at 60℃ and the pressure at -0.09MPa, and rotary evaporate for 1-2 hours to obtain dried polyethylene glycol; Step 2. Dry ethylenediamine using 4A molecular sieve for 24 hours to obtain dried ethylenediamine; Step 3. Add dried polyethylene glycol to the reaction vessel, purge with nitrogen gas at a flow rate of 50 mL / min for 30 minutes, add sodium methoxide and stir at a speed of 400-500 rpm, heat to 60℃ and stir for 20 minutes, add dried ethylenediamine dropwise at a rate of 1 drop / second, stir after all has been added, maintain the temperature at 80℃ and the speed at 350-400 rpm for 5 hours to obtain a mixed polyethylene glycol solvent; Step 4. Cool the polyethylene glycol mixed solvent to 18-25℃, add deionized water, stir for 10 minutes, add hydrochloric acid, and extract with dichloromethane using a separatory funnel to obtain the organic phase. Dry the organic phase with anhydrous sodium sulfate for 2 hours, filter out the anhydrous sodium sulfate, and evaporate using a rotary evaporator at 40℃ and -0.09MPa to obtain the crude product. Add the crude product and ethanol to a reaction vessel and stir magnetically at 300-400 rpm at 60-70℃ for 5-10 minutes. Cool the temperature to 20-25℃. The reaction vessel was placed in a water bath at 0-4℃ and allowed to stand for 1-2 hours to obtain white crystals. The white crystals were washed with anhydrous ethanol. The washed white crystals and ethanol were added to the reaction vessel. The stirring speed was 300-400 rpm and the temperature was controlled at 55-65℃. The mixture was stirred for 5-10 minutes. The temperature was cooled to 20-25℃, and the reaction vessel was placed in a water bath at 0-4℃ and allowed to stand for 1-2 hours to obtain pure crystals. The pure crystals were placed in a vacuum drying oven and dried at 60℃ and -0.09MPa for 8 hours to obtain modified polyethylene glycol.

[0024] Step 4: The mass ratio of dichloromethane to deionized water is 1:1; The mass ratio of tetrachloromethane to polyethylene glycol is 1:1.

[0025] Furthermore, the mass ratio of the crude product to ethanol in step four is 1:3; The mass ratio of white crystals to anhydrous ethanol is 1:3.

[0026] The preparation of modified guar gum powder includes the following steps: Guar gum powder, sodium chloride, and deionized water are added to a water bath reactor and stirred at 200-400 rpm and 40-50℃ for 1-2 hours to obtain a guar gum powder emulsion. Sodium hydroxide solution is added to the guar gum powder emulsion to adjust the pH value. Sodium trimetaphosphate is added and stirred for 1-2 hours. Dilute hydrochloric acid is added to adjust the pH value. The water is filtered off, and the remaining solid is washed with deionized water. The solid is placed in a drying oven and dried at 60-70℃ for 6-12 hours. The dried solid is then ground to 80-120 mesh using a grinder to obtain modified guar gum powder.

[0027] The mass ratio of guar gum powder, sodium trimetaphosphate, and sodium chloride is 1:0.01-0.02:0.01-0.05; Sodium hydroxide solution was added to the guar gum emulsion to adjust the pH to 9-11; Adjust the pH to 6-7 with dilute hydrochloric acid.

[0028] The preparation of modified hexadecyltrimethylammonium bromide includes the following steps: Hexadecyltrimethylammonium bromide and deionized water are added to a reaction vessel and stirred at 200 rpm for 30 minutes. Potassium persulfate is added and stirred for 10 minutes. Sodium hydroxide is added and stirred. The temperature is heated to 40-60℃ and stirred at 300 rpm for 1-3 hours. The mixture is cooled to 18-25℃ and sodium sulfite is added and stirred for 10 minutes. Deionized water is added and the mixture is dialyzed using a dialysis bag for 24 hours, with the deionized water being replaced every 6 hours. The dialyzed solution is evaporated on a rotary evaporator at 40℃ and 0.08 MPa for 1-1.5 hours. The solution is then dried in a vacuum drying oven at 40℃ for 12 hours to obtain modified hexadecyltrimethylammonium bromide.

[0029] Furthermore, the mass ratio of hexadecyltrimethylammonium bromide and deionized water added to the reactor is 1:27.5; The molar ratio of hexadecyltrimethylammonium bromide to potassium persulfate is 1:0.3; The molar ratio of sodium sulfite to potassium persulfate is 1.1:1; Add sodium hydroxide to adjust the pH to 5.8-6.2.

[0030] Example 2, a catalyst for the hydrogenation of phenol to cyclohexanone, is composed of the following raw materials in parts by weight: 65 parts γ-alumina, 1 part modified polyethylene glycol, 0.55 parts modified hexadecyltrimethylammonium bromide, 2 parts palladium acetate, 5-10 parts 25% ammonia water, 11 parts ethanol, 7.5 parts modified guar gum powder and 6.5 parts tetraethyl orthosilicate; The preparation of the catalyst for the hydrogenation of phenol to cyclohexanone includes the following steps: S1. Place γ-alumina in a muffle furnace and calcine it at 5℃ / min to 550℃, hold it at that temperature for 4 hours to obtain dry γ-alumina; add modified guar gum powder and dry γ-alumina into a reaction vessel, add ethanol accounting for 5% of the total ethanol and knead to obtain a moist composite carrier; place the moist composite carrier in a drying oven and dry it at 110℃ for 4 hours, then calcine it in a muffle furnace at 300℃ for 2 hours to obtain the composite carrier; S2. Add the composite carrier and 40% ethanol (based on the total ethanol content) to a reaction vessel and stir at 200-300 rpm for 15-30 minutes to obtain a composite carrier solution. Dissolve tetraethyl orthosilicate in 20% ethanol (based on the total ethanol content) to obtain a tetraethyl orthosilicate solution. Add the composite carrier solution to a water bath reaction vessel, add the tetraethyl orthosilicate solution and stir at 200-300 rpm for 10-15 minutes. Add 25% ammonia solution and stir at 60℃ for 400-600 rpm for 2-3 hours to obtain a modified composite solution. S3. Dissolve palladium acetate in ethanol accounting for 30% of the total ethanol content, add modified hexadecyltrimethylammonium bromide and modified polyethylene glycol, stir at 300-400 rpm for 15-30 minutes, add the modified composite solution, stir at 100-200 rpm for 12 hours, add ethanol accounting for 5% of the total ethanol content, heat to 60℃, purge with a mixed gas of hydrogen and nitrogen, hydrogen concentration 10%, purge with a mixed gas flow rate of 50 mL / min for 2 hours, filter out the filtrate, and dry the remaining solid in a drying oven at 100℃ for 6 hours to obtain the dried catalyst; S4. Grind the dried catalyst into powder, place the powder in a tube furnace for calcination, introduce nitrogen gas, heat to 300-400℃ at a heating rate of 5℃ / min, and hold for 2 hours to obtain the catalyst for the hydrogenation of phenol to cyclohexanone.

[0031] Add ammonia to adjust the pH to 8-9; The hydrogen concentration in S3 is 10%; The dried catalyst in S4 is ground to 80-150 mesh.

[0032] Modified polyethylene glycol comprises the following components: 95-105 parts polyethylene glycol, 55-65 parts ethylenediamine, and 1-2 parts sodium methoxide.

[0033] The preparation of modified polyethylene glycol includes the following steps: Step 1. Connect the reactor to the rotary evaporator, add polyethylene glycol to the reactor, control the temperature at 60℃ and the pressure at -0.09MPa, and rotary evaporate for 1-2 hours to obtain dried polyethylene glycol; Step 2. Dry ethylenediamine using 4A molecular sieve for 24 hours to obtain dried ethylenediamine; Step 3. Add dried polyethylene glycol to the reaction vessel, purge with nitrogen gas at a flow rate of 50 mL / min for 30 minutes, add sodium methoxide and stir at a speed of 400-500 rpm, heat to 60℃ and stir for 20 minutes, add dried ethylenediamine dropwise at a rate of 1 drop / second, stir after all has been added, maintain the temperature at 80℃ and the speed at 350-400 rpm for 5 hours to obtain a mixed polyethylene glycol solvent; Step 4. Cool the polyethylene glycol mixed solvent to 18-25℃, add deionized water, stir for 10 minutes, add hydrochloric acid, and extract with dichloromethane using a separatory funnel to obtain the organic phase. Dry the organic phase with anhydrous sodium sulfate for 2 hours, filter out the anhydrous sodium sulfate, and evaporate using a rotary evaporator at 40℃ and -0.09MPa to obtain the crude product. Add the crude product and ethanol to a reaction vessel and stir magnetically at 300-400 rpm at 60-70℃ for 5-10 minutes. Cool the temperature to 20-25℃. The reaction vessel was placed in a water bath at 0-4℃ and allowed to stand for 1-2 hours to obtain white crystals. The white crystals were washed with anhydrous ethanol. The washed white crystals and ethanol were added to the reaction vessel. The stirring speed was 300-400 rpm and the temperature was controlled at 55-65℃. The mixture was stirred for 5-10 minutes. The temperature was cooled to 20-25℃, and the reaction vessel was placed in a water bath at 0-4℃ and allowed to stand for 1-2 hours to obtain pure crystals. The pure crystals were placed in a vacuum drying oven and dried at 60℃ and -0.09MPa for 8 hours to obtain modified polyethylene glycol.

[0034] Step 4: The mass ratio of dichloromethane to deionized water is 1:1; The mass ratio of tetrachloromethane to polyethylene glycol is 1:1.

[0035] The mass ratio of crude product to ethanol in step four is 1:3; The mass ratio of white crystals to anhydrous ethanol is 1:3.

[0036] The preparation of modified guar gum powder includes the following steps: Guar gum powder, sodium chloride, and deionized water are added to a water bath reactor and stirred at 200-400 rpm and 40-50℃ for 1-2 hours to obtain a guar gum powder emulsion. Sodium hydroxide solution is added to the guar gum powder emulsion to adjust the pH value. Sodium trimetaphosphate is added and stirred for 1-2 hours. Dilute hydrochloric acid is added to adjust the pH value. The water is filtered off, and the remaining solid is washed with deionized water. The solid is placed in a drying oven and dried at 60-70℃ for 6-12 hours. The dried solid is then ground to 80-120 mesh using a grinder to obtain modified guar gum powder.

[0037] The mass ratio of guar gum powder, sodium trimetaphosphate, and sodium chloride is 1:0.01-0.02:0.01-0.05; Sodium hydroxide solution was added to the guar gum emulsion to adjust the pH to 9-11; Adjust the pH to 6-7 with dilute hydrochloric acid.

[0038] The preparation of modified hexadecyltrimethylammonium bromide includes the following steps: Hexadecyltrimethylammonium bromide and deionized water are added to a reaction vessel and stirred at 200 rpm for 30 minutes. Potassium persulfate is added and stirred for 10 minutes. Sodium hydroxide is added and stirred. The temperature is heated to 40-60℃ and stirred at 300 rpm for 1-3 hours. The mixture is cooled to 18-25℃ and sodium sulfite is added and stirred for 10 minutes. Deionized water is added and the mixture is dialyzed using a dialysis bag for 24 hours, with the deionized water being replaced every 6 hours. The dialyzed solution is evaporated on a rotary evaporator at 40℃ and 0.08 MPa for 1-1.5 hours. The solution is then dried in a vacuum drying oven at 40℃ for 12 hours to obtain modified hexadecyltrimethylammonium bromide.

[0039] The mass ratio of hexadecyltrimethylammonium bromide and deionized water added to the reactor is 1:27.5; The molar ratio of hexadecyltrimethylammonium bromide to potassium persulfate is 1:0.3; The molar ratio of sodium sulfite to potassium persulfate is 1.1:1; Add sodium hydroxide to adjust the pH to 5.8-6.2.

[0040] Example 3, a catalyst for the hydrogenation of phenol to cyclohexanone, is composed of the following raw materials in parts by weight: 70 parts γ-alumina, 1.5 parts modified polyethylene glycol, 0.8 parts modified hexadecyltrimethylammonium bromide, 2.5 parts palladium acetate, 10 parts 25% ammonia water, 120 parts ethanol, 10 parts modified guar gum powder and 8 parts tetraethyl orthosilicate; The preparation of the catalyst for the hydrogenation of phenol to cyclohexanone includes the following steps: S1. Place γ-alumina in a muffle furnace and calcine it at 5℃ / min to 550℃, hold it at that temperature for 4 hours to obtain dry γ-alumina; add modified guar gum powder and dry γ-alumina into a reaction vessel, add ethanol accounting for 5% of the total ethanol and knead to obtain a moist composite carrier; place the moist composite carrier in a drying oven and dry it at 110℃ for 4 hours, then calcine it in a muffle furnace at 300℃ for 2 hours to obtain the composite carrier; S2. Add the composite carrier and 40% ethanol (based on the total ethanol content) to a reaction vessel and stir at 200-300 rpm for 15-30 minutes to obtain a composite carrier solution. Dissolve tetraethyl orthosilicate in 20% ethanol (based on the total ethanol content) to obtain a tetraethyl orthosilicate solution. Add the composite carrier solution to a water bath reaction vessel, add the tetraethyl orthosilicate solution and stir at 200-300 rpm for 10-15 minutes. Add 25% ammonia solution and stir at 60℃ for 400-600 rpm for 2-3 hours to obtain a modified composite solution. S3. Dissolve palladium acetate in ethanol accounting for 30% of the total ethanol content, add modified hexadecyltrimethylammonium bromide and modified polyethylene glycol, stir at 300-400 rpm for 15-30 minutes, add the modified composite solution, stir at 100-200 rpm for 12 hours, add ethanol accounting for 5% of the total ethanol content, heat to 60℃, purge with a mixed gas of hydrogen and nitrogen, hydrogen concentration 10%, purge with a mixed gas flow rate of 50 mL / min for 2 hours, filter out the filtrate, and dry the remaining solid in a drying oven at 100℃ for 6 hours to obtain the dried catalyst; S4. Grind the dried catalyst into powder, place the powder in a tube furnace for calcination, introduce nitrogen gas, heat to 300-400℃ at a heating rate of 5℃ / min, and hold for 2 hours to obtain the catalyst for the hydrogenation of phenol to cyclohexanone.

[0041] Add ammonia to adjust the pH to 8-9; The hydrogen concentration in S3 is 10%; The dried catalyst in S4 is ground to 80-150 mesh.

[0042] Modified polyethylene glycol comprises the following components: 95-105 parts polyethylene glycol, 55-65 parts ethylenediamine, and 1-2 parts sodium methoxide.

[0043] The preparation of modified polyethylene glycol includes the following steps: Step 1. Connect the reactor to the rotary evaporator, add polyethylene glycol to the reactor, control the temperature at 60℃ and the pressure at -0.09MPa, and rotary evaporate for 1-2 hours to obtain dried polyethylene glycol; Step 2. Dry ethylenediamine using 4A molecular sieve for 24 hours to obtain dried ethylenediamine; Step 3. Add dried polyethylene glycol to the reaction vessel, purge with nitrogen gas at a flow rate of 50 mL / min for 30 minutes, add sodium methoxide and stir at a speed of 400-500 rpm, heat to 60℃ and stir for 20 minutes, add dried ethylenediamine dropwise at a rate of 1 drop / second, stir after all has been added, maintain the temperature at 80℃ and the speed at 350-400 rpm for 5 hours to obtain a mixed polyethylene glycol solvent; Step 4. Cool the polyethylene glycol mixed solvent to 18-25℃, add deionized water, stir for 10 minutes, add hydrochloric acid, and extract with dichloromethane using a separatory funnel to obtain the organic phase. Dry the organic phase with anhydrous sodium sulfate for 2 hours, filter out the anhydrous sodium sulfate, and evaporate using a rotary evaporator at 40℃ and -0.09MPa to obtain the crude product. Add the crude product and ethanol to a reaction vessel and stir magnetically at 300-400 rpm at 60-70℃ for 5-10 minutes. Cool the temperature to 20-25℃. The reaction vessel was placed in a water bath at 0-4℃ and allowed to stand for 1-2 hours to obtain white crystals. The white crystals were washed with anhydrous ethanol. The washed white crystals and ethanol were added to the reaction vessel. The stirring speed was 300-400 rpm and the temperature was controlled at 55-65℃. The mixture was stirred for 5-10 minutes. The temperature was cooled to 20-25℃, and the reaction vessel was placed in a water bath at 0-4℃ and allowed to stand for 1-2 hours to obtain pure crystals. The pure crystals were placed in a vacuum drying oven and dried at 60℃ and -0.09MPa for 8 hours to obtain modified polyethylene glycol.

[0044] Step 4: The mass ratio of dichloromethane to deionized water is 1:1; The mass ratio of tetrachloromethane to polyethylene glycol is 1:1.

[0045] The mass ratio of crude product to ethanol in step four is 1:3; The mass ratio of white crystals to anhydrous ethanol is 1:3.

[0046] The preparation of modified guar gum powder includes the following steps: Guar gum powder, sodium chloride, and deionized water are added to a water bath reactor and stirred at 200-400 rpm and 40-50℃ for 1-2 hours to obtain a guar gum powder emulsion. Sodium hydroxide solution is added to the guar gum powder emulsion to adjust the pH value. Sodium trimetaphosphate is added and stirred for 1-2 hours. Dilute hydrochloric acid is added to adjust the pH value. The water is filtered off, and the remaining solid is washed with deionized water. The solid is placed in a drying oven and dried at 60-70℃ for 6-12 hours. The dried solid is then ground to 80-120 mesh using a grinder to obtain modified guar gum powder.

[0047] The mass ratio of guar gum powder, sodium trimetaphosphate, and sodium chloride is 1:0.01-0.02:0.01-0.05; Sodium hydroxide solution was added to the guar gum emulsion to adjust the pH to 9-11; Adjust the pH to 6-7 with dilute hydrochloric acid.

[0048] The preparation of modified hexadecyltrimethylammonium bromide includes the following steps: Hexadecyltrimethylammonium bromide and deionized water are added to a reaction vessel and stirred at 200 rpm for 30 minutes. Potassium persulfate is added and stirred for 10 minutes. Sodium hydroxide is added and stirred. The temperature is heated to 40-60℃ and stirred at 300 rpm for 1-3 hours. The mixture is cooled to 18-25℃ and sodium sulfite is added and stirred for 10 minutes. Deionized water is added and the mixture is dialyzed using a dialysis bag for 24 hours, with the deionized water being replaced every 6 hours. The dialyzed solution is evaporated on a rotary evaporator at 40℃ and 0.08 MPa for 1-1.5 hours. The solution is then dried in a vacuum drying oven at 40℃ for 12 hours to obtain modified hexadecyltrimethylammonium bromide.

[0049] The mass ratio of hexadecyltrimethylammonium bromide and deionized water added to the reactor is 1:27.5; The molar ratio of hexadecyltrimethylammonium bromide to potassium persulfate is 1:0.3; The molar ratio of sodium sulfite to potassium persulfate is 1.1:1; Add sodium hydroxide to adjust the pH to 5.8-6.2.

[0050] Comparative Example 1: The difference between this comparative example and Example 1 is that this example does not contain modified guar gum powder.

[0051] Comparative Example 2 differs from Example 1 in that it does not contain hexadecyltrimethylammonium bromide.

[0052] Comparative Example 3 differs from Example 1 in that it does not contain modified polyethylene glycol.

[0053] Performance testing: The relevant performance of the samples prepared by the phenol hydrogenation to cyclohexanone catalysts provided in Examples 1-3 and Comparative Examples 1-3 were tested respectively, and the test data are recorded in Table 1 below:

[0054] Among them, the phenol hydrogenation to cyclohexanone catalysts prepared in Examples 1, 2, 3, Comparative Examples 1, 2, and 3 retained 93.6%, 94.4%, 93.7%, 83.3%, 86.5%, and 80.8% of their activity after 100 h, respectively; the Pd dispersion of the phenol hydrogenation to cyclohexanone catalysts prepared in Examples 1, 2, 3, Comparative Examples 1, 2, and 3 was 66.8%, 72.5%, 67.3%, 31.4%, 48.2%, and 36.1%, respectively; and the phenol hydrogenation to cyclohexanone catalysts prepared in Examples 1, 2, 3, Comparative Examples 1, 2, and 3 retained 93.6%, 94.4%, 93.7%, 83.3%, 86.5%, and 80.8% of their activity after 100 h, respectively. The carbon deposition rates at different h were 1.8%, 1.4%, 1.7%, 3.6%, 4.1%, and 3.8%, respectively. Comparison and analysis of the relevant data in Table 1 show that the phenol hydrogenation to cyclohexanone catalyst prepared in this invention not only exhibits good 100-hour activity retention, good Pd dispersion, and low carbon deposition, but also demonstrates that the preparation method of the phenol hydrogenation to cyclohexanone catalyst provided by this invention has a broader market prospect and is more suitable for widespread application.

[0055] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0056] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A catalyst for the hydrogenation of phenol to cyclohexanone, characterized in that, It is composed of the following raw materials in parts by weight: 60-70 parts γ-alumina, 0.5-1.5 parts modified polyethylene glycol, 0.3-0.8 parts modified hexadecyltrimethylammonium bromide, 1.5-2.5 parts palladium acetate, 5-10 parts 25% ammonia water, 100-120 parts ethanol, 5-10 parts modified guar gum powder and 5-8 parts tetraethyl orthosilicate; The preparation of the catalyst for the hydrogenation of phenol to cyclohexanone includes the following steps: S1. Place γ-alumina in a muffle furnace and calcine to obtain dry γ-alumina; add modified guar gum powder and dry γ-alumina to a reaction vessel, add ethanol accounting for 5% of the total ethanol and knead to obtain a wet composite carrier; place the wet composite carrier in a drying oven to dry, and calcine it in a muffle furnace to obtain a composite carrier. S2. Add the composite carrier and 40% of the total ethanol to a reaction vessel and stir to obtain a composite carrier solution; dissolve tetraethyl orthosilicate in 20% of the total ethanol to obtain a tetraethyl orthosilicate solution; add the composite carrier solution to a water bath reaction vessel, add the tetraethyl orthosilicate solution and stir, add 25% ammonia water and stir to obtain a modified composite solution. S3. Dissolve palladium acetate in ethanol accounting for 30% of the total ethanol, add modified hexadecyltrimethylammonium bromide and modified polyethylene glycol and stir, add modified composite solution and stir, add ethanol accounting for 5% of the total ethanol and heat to 60°C, pass in a mixture of hydrogen and nitrogen gas, filter out the filtrate, and dry the remaining solid in a drying oven to obtain a dried catalyst. S4. Grind the dried catalyst, place the powder in a tube furnace and calcine it under nitrogen gas to obtain a catalyst for the hydrogenation of phenol to cyclohexanone.

2. The catalyst for the hydrogenation of phenol to cyclohexanone according to claim 1, characterized in that, Ammonia water is added to S2 to adjust the pH value to 8-9; The hydrogen concentration in S3 is 10%; The dried catalyst in S4 is ground to 80-150 mesh.

3. The catalyst for the hydrogenation of phenol to cyclohexanone according to claim 1, characterized in that, The modified polyethylene glycol comprises the following components: 95-105 parts polyethylene glycol, 55-65 parts ethylenediamine, and 1-2 parts sodium methoxide.

4. The catalyst for the hydrogenation of phenol to cyclohexanone according to claim 1, characterized in that, The preparation of the modified polyethylene glycol includes the following steps: Step 1. Connect the reactor to the rotary evaporator, add polyethylene glycol to the reactor, control the temperature at 60℃ and the pressure at -0.09MPa, and rotary evaporate for 1-2 hours to obtain dried polyethylene glycol; Step 2. Dry ethylenediamine using 4A molecular sieve for 24 hours to obtain dried ethylenediamine; Step 3. Add dried polyethylene glycol to the reaction vessel, purge with nitrogen, add sodium methoxide and stir, heat to 60°C and stir for 20 minutes, add dried ethylenediamine dropwise, stir after all is added, heat to 80°C to obtain a polyethylene glycol mixed solvent; Step 4. Cool the polyethylene glycol mixed solvent to 18-25℃, add deionized water, stir for 10 minutes, add hydrochloric acid, and extract with dichloromethane using a separatory funnel to obtain an organic phase. Dry the organic phase with anhydrous sodium sulfate, filter out the anhydrous sodium sulfate, and evaporate using a rotary evaporator to obtain a crude product. Add the crude product and ethanol to a reaction vessel and stir magnetically. Cool the temperature to 20-25℃ and place the reaction vessel in a water bath to stand, obtaining white crystals. Wash the white crystals with anhydrous ethanol, add the washed white crystals and ethanol to the reaction vessel and stir. Cool the temperature to 20-25℃ and place the reaction vessel in a water bath to stand, obtaining pure crystals. Place the pure crystals in a vacuum drying oven to dry, obtaining modified polyethylene glycol.

5. The catalyst for the hydrogenation of phenol to cyclohexanone according to claim 4, characterized in that, In step four, the mass ratio of dichloromethane to deionized water is 1:

1. The mass ratio of tetrachloromethane to polyethylene glycol is 1:

1.

6. The catalyst for the hydrogenation of phenol to cyclohexanone according to claim 4, characterized in that, In step four, the mass ratio of crude product to ethanol is 1:

3. The mass ratio of white crystals to anhydrous ethanol is 1:

3.

7. The catalyst for the hydrogenation of phenol to cyclohexanone according to claim 1, characterized in that, The preparation of the modified guar gum powder includes the following steps: Sesbania powder, sodium chloride, and deionized water were added to a water bath reactor and stirred at a temperature of 40-50℃ to obtain a sesbania powder emulsion. Sodium hydroxide solution was added to the sesbania powder emulsion to adjust the pH value. Sodium trimetaphosphate was added and stirred. Dilute hydrochloric acid was added, and the water was filtered off. The remaining solid was washed with deionized water and dried in a drying oven. The dried solid was then ground using a grinder to obtain modified sesbania powder.

8. The catalyst for the hydrogenation of phenol to cyclohexanone according to claim 7, characterized in that, The mass ratio of guar gum powder, sodium trimetaphosphate, and sodium chloride is 1:0.01-0.02:0.01-0.05; Sodium hydroxide solution was added to the guar gum emulsion to adjust the pH to 9-11; Adjust the pH to 6-7 with dilute hydrochloric acid.

9. The catalyst for the hydrogenation of phenol to cyclohexanone according to claim 1, characterized in that, The preparation of the modified hexadecyltrimethylammonium bromide includes the following steps: Hexadecyltrimethylammonium bromide and deionized water were added to a reaction vessel and stirred. Potassium persulfate was added and stirred for 10 minutes. Sodium hydroxide was added and stirred. The temperature was heated to 40-60℃ and the stirring speed was 300 rpm for 1-3 hours. The mixture was cooled to 18-25℃ and sodium sulfite was added and stirred. Deionized water was added and dialyzed using a dialysis bag for 24 hours, with the deionized water being replaced every 6 hours. The dialyzed solution was evaporated on a rotary evaporator and dried using a vacuum drying oven to obtain modified hexadecyltrimethylammonium bromide.

10. The catalyst for the hydrogenation of phenol to cyclohexanone according to claim 9, characterized in that, The mass ratio of hexadecyltrimethylammonium bromide and deionized water added to the reactor is 1:27.5; The molar ratio of hexadecyltrimethylammonium bromide to potassium persulfate is 1:0.3; The molar ratio of sodium sulfite to potassium persulfate is 1.1:1; Add sodium hydroxide to adjust the pH to 5.8-6.2.

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