Activated catalyst for the synthesis of methyl p-t-butylbenzoate and process for its preparation

Abstract

The application discloses an activated catalyst for synthesizing methyl p-tert-butylbenzoate and a preparation method thereof, and belongs to the technical field of catalyst preparation. In the prior art, when methyl p-tert-butylbenzoate is synthesized, the resin catalyst is used in the esterification process, and the catalytic efficiency is low; the ionic liquid catalyst is used, and the ionic liquid catalyst has the technical problems of being difficult to separate, difficult to recycle, and not suitable for continuous industrial production. The application provides a preparation method of the activated catalyst for synthesizing methyl p-tert-butylbenzoate, and the method comprises the following steps: S1, mixing a strong-acid solid catalyst and a modified molecular sieve, and ball milling to obtain a mixture; and S2, activating the mixture in ionic liquid containing magnesium and aluminum metal elements to synthesize the activated catalyst for synthesizing methyl p-tert-butylbenzoate. The prepared activated catalyst has the advantages of corrosion resistance, high catalytic efficiency and repeated recycling.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of catalyst preparation, in particular to an activated catalyst for synthesizing methyl p-tert-butylbenzoate and a preparation method thereof. BACKGROUND

[0002] Methyl p-tert-butylbenzoate is an important pharmaceutical and chemical intermediate and an organic synthesis intermediate, which is widely used in the production of chemical synthesis, pharmaceuticals, cosmetics, and fragrances, and has a large market demand. In large-scale industrial production, p-tert-butylbenzoic acid and anhydrous methanol are usually used as raw materials to generate methyl p-tert-butylbenzoate through esterification under the action of a catalyst. In the above esterification process, commonly used catalysts include resin solid catalysts and ionic liquid catalysts; ionic liquid catalysts have higher catalytic efficiency, but are not easy to separate and are not suitable for continuous industrial production.

[0003] Patent application CN107311868A discloses a method for preparing methyl p-tert-butylbenzoate. The above esterification process uses sulfonic acid resin as an esterification catalyst; the sulfonic acid resin catalyst has the advantages of no equipment corrosion, easy separation of products, and recyclable catalyst, and is suitable for large-scale industrial production. However, the resin catalyst has the disadvantages of weak acidity and low catalytic efficiency.

[0004] In view of the above technical defects, a solution is proposed. SUMMARY

[0005] The present application relates to the technical field of catalyst preparation, in particular to an activated catalyst for synthesizing methyl p-tert-butylbenzoate and a preparation method thereof.

[0006] The purpose of the present application can be achieved by the following technical solution: a preparation method of an activated catalyst for synthesizing methyl p-tert-butylbenzoate, comprising the following steps:

[0007] S1, mixing and ball milling of a strong acid solid catalyst and a modified molecular sieve to obtain a mixture;

[0008] S2, activating the mixture in a metal ionic liquid, then filtering to obtain a solid; cold pressing the solid to obtain a pre-pressed block; drying the pre-pressed block and then naturally cooling to obtain an activated catalyst for synthesizing methyl p-tert-butylbenzoate.

[0009] The synthetic catalyst is an impregnated catalyst, i.e., the strong-acid solid catalyst and the modified molecular sieve are mixed, and then impregnated in a metal ion liquid to synthesize the impregnated catalyst.

[0010] Further, in step S1, the preparation method of the strong-acid solid catalyst comprises the following steps:

[0011] A1, gelatin is completely dissolved in deionized water to obtain a mixed solution; then, a NaOH solution is added dropwise to adjust the pH value of the mixed solution to 7 to obtain an aqueous phase; di-vinyl benzene, glycerol trimethyl acrylate and an initiator are uniformly mixed to obtain an oil phase mixture; the oil phase mixture is added to the aqueous phase to obtain a reaction system; the reaction system is heated to 75-80 DEG C, and reacted at this temperature for 2-3 h to obtain a prepolymer;

[0012] Gelatin is used as a dispersant, and the gelatin is dissolved in water to obtain an aqueous phase; under the action of an initiator, di-vinyl benzene monomers and glycerol trimethyl acrylate undergo free radical polymerization to form a prepolymer, which is the skeleton of the prepared strong-acid solid catalyst.

[0013] A2, glycidyl methacrylate is added to the prepolymer, and then heated to 90-95 DEG C, and reacted at this temperature for 2-4 h; then, the reaction is stopped, and cooled to room temperature; after post-process treatment, a polymeric sphere is obtained;

[0014] Under the action of the initiator, the prepolymer continues to react with the unsaturated double bond in the glycidyl methacrylate to obtain a polymeric sphere grafted with glycidyl methacrylate.

[0015] The di-vinyl benzene monomers and the glycerol trimethyl acrylate undergo a polymerization reaction, and then the glycidyl methacrylate is crosslinked to prepare the polymeric sphere, and the reaction formula is as follows:

[0016]

[0017] A3, sodium sulfamate is dissolved in water, and then aluminum chloride is added and uniformly mixed to obtain a mixture; the mixture is heated to 80-100 DEG C, and a NaOH solution is added dropwise to adjust the pH value of the mixture to 8-10; then, the polymeric sphere is added, and reacted at 80-100 DEG C for 15-20 h; after post-process treatment, a strong-acid solid catalyst is prepared.

[0018] The epoxy groups in the polymeric sphere react with the sodium sulfamate to graft a plurality of sulfonic acid groups; the polymeric sphere can adsorb Lewis acid aluminum chloride to prepare the strong-acid solid catalyst.

[0019] Further, in step A1, the ratio of gelatin and deionized water is 0.02-0.03 g:150-200 mL, the initiator is azobisisobutyronitrile; the ratio of divinylbenzene, glycerol trimethacrylate and initiator is 30 g:20-30 g:0.3-0.5 g; the ratio of oil phase mixture and water phase is 50-60 g:200 g; in step A2, the ratio of prepolymer and glycidyl methacrylate is 250 g:10-20 g; the post-processing step includes: using a Buchner funnel to filter, then washing with deionized water three times, to obtain a beaded resin; the beaded resin is dried in an oven at 80°C to constant weight to obtain a polymer sphere.

[0020] Further, in step A3, the ratio of sodium sulfamate, water and aluminum chloride is 3-5 g:20 mL:1.5-2.5 g, the ratio of mixture and polymer sphere is 20 g:200-250 g; the post-processing step includes: using a Buchner funnel to filter, then washing with deionized water three times, and drying in an oven at 80°C to constant weight to obtain a strong acid solid catalyst.

[0021] Further, the preparation method of the modified molecular sieve includes the following steps:

[0022] B1, ZSM-5 molecular sieve is immersed in H2SO4 solution for 30-60 min, then filtered, and the solid is collected to obtain an acidified molecular sieve;

[0023] The ZSM-5 molecular sieve is acidified by a sulfuric acid solution, which can enrich the acid sites of the ZSM-5 molecular sieve.

[0024] B2, toluene diisocyanate and trifluoroethanol are mixed to obtain a polyester prepolymer solution; the acidified molecular sieve and the polyester prepolymer solution are mixed to obtain a polyester suspension; a curing agent is added to the polyester suspension, stirred, vacuum degassed, and cured at 70-80°C for 3-4 h to obtain a modified molecular sieve.

[0025] The reaction formula for synthesizing the polyester prepolymer solution by the reaction of toluene diisocyanate and trifluoroethanol is as follows:

[0026]

[0027] Further, in step B1, the concentration of the H2SO4 solution is 0.5-1 mol / L, and the ratio of ZSM-5 molecular sieve and H2SO4 solution is 5.00-10.00 g:100 mL; in step B2, the ratio of toluene diisocyanate and trifluoroethanol is 17-35 g:5-10 g, and the ratio of acidified molecular sieve and polyester prepolymer solution is 2-5 g:50 mL; the curing agent is methyl isobutyl ketone peroxide, and the ratio of polyester suspension and curing agent is 45-50 mL:0.5 g.

[0028] Further, in step S1, the mass ratio of the strong-acid solid catalyst and the modified molecular sieve is 1:1; the ball milling rotation speed is 200-300 r / min, and the ball milling time is 20-30 min.

[0029] Further, in step S2, the preparation method of the metal ionic liquid comprises the following steps:

[0030] 10-15 g of N-methyl morphine, 5-20 mL of n-butyl bromide and 50-100 mL of acetone are mixed and stirred to generate white solid; the white solid is vacuum filtered and dried to obtain an intermediate; 50 mL of deionized water, 10-15 g of the intermediate, 2.35-5.5 g of MgCl2 and 1-2 g of AlCl3 are uniformly mixed to obtain a reactant; the reactant is reacted at 70-80℃ for 2-3 h, and then water in the reactant is removed by rotary evaporation under reduced pressure to obtain the metal ionic liquid.

[0031] Further, in step S2, the drying temperature is 100-110℃, and the drying time is 50-60 min.

[0032] As another aspect of the application, the activated catalyst for synthesizing methyl p-tert-butyl benzoate is prepared by the preparation method of the activated catalyst for synthesizing methyl p-tert-butyl benzoate.

[0033] The application has the following advantages:

[0034] 1. The activated catalyst synthesized by the application is activated by adding a strong-acid solid catalyst and a modified molecular sieve into a metal ionic liquid. In the synthesis of the strong-acid solid catalyst, di-vinyl benzene and trimethyl acrylate monomer containing multiple double bonds are used as the skeleton to synthesize high-density polymer spheres; sodium sulfamate is grafted onto the polymer spheres to enrich the number of sulfonic acid groups. In addition, a small amount of Lewis acid aluminum chloride is added to combine with sodium sulfamate, further enhancing the acidity of the strong-acid solid catalyst.

[0035] 2、The modified molecular sieve selects ZSM-5 molecular sieve, the above-mentioned molecular sieve belongs to MFI topology structure, orthorhombic system;The framework structure comprises two kinds of vertical intersecting ten-membered ring channels, the straight mouth is elliptical ten-member of ring, and the other is "Z" shape mouth opening close to circular ten-membered ring, and the pore size is 0.5nm, and the size at the intersection of two kinds of channels is 0.9-1nm.Toluene diisocyanate and trifluoroethanol are used as polyester components, and then mixed with acidified ZSM-5 molecular sieve to form a polyester suspension.After curing process, the cured polyester can firmly fix the molecular sieve particles;The uniform dispersion of molecular sieve in polyester can avoid the direct influence of external environment, thereby improving the use stability and service life of the synthesized molecular sieve.The synthesized polyester contains polyfluoro elements, thereby improving the corrosion resistance of the synthesized modified molecular sieve.

[0036] 3、The present application uses N-methyl morphine and bromine n-butane as raw materials to synthesize Lewis acid metal ionic liquid.By adding magnesium and aluminum chlorides to prepare bimetallic coordination ionic liquid, which can further improve the catalytic activity of the synthesized ionic liquid.The strong acid solid catalyst and the modified molecular sieve are mixed uniformly and then activated in the metal ionic liquid, and after post-process treatment, the prepared activated catalyst can further improve its adsorption performance and catalytic efficiency.The synthesized activated catalyst has the advantages of corrosion resistance, high catalytic efficiency and repeated recycling, and is suitable for large-scale industrialization and continuous production process of methyl tert-butyl benzoate. DETAILED DESCRIPTION

[0037] The technical solutions of the present application will be described below in conjunction with the embodiments, obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments.Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

[0038] The ZSM-5 molecular sieve catalysts selected in embodiments 4-6 of the present application are purchased from Liaoning Raodong New Material Co., Ltd., and the specific surface area is greater than or equal to 350m 2 / g, the crystal grain size is 0.3-10μm, and the pore size is 0.5nm.

[0039] Embodiment 1

[0040] The present embodiment provides a preparation method of a strong acid solid catalyst for synthesizing an activated catalyst for methyl tert-butyl benzoate, comprising the following steps:

[0041] A1, in a 500 mL four-necked flask equipped with a stirrer, a condenser and a thermometer, 200 mL of deionized water was added, followed by 0.02 g of gelatin, and stirred until the gelatin was completely dissolved in the deionized water to obtain a mixed solution; then 1 mol / L NaOH solution was added dropwise to adjust the pH value of the mixed solution to 7 to prepare an aqueous phase. 30 g of divinylbenzene monomer, 20 g of glyceryl trimethacrylate and 0.3 g of initiator azobisisobutyronitrile were mixed to obtain an oil phase mixture. 50 g of the oil phase mixture was added to 200 g of the aqueous phase, and stirred to disperse the oil phase monomer droplets in the aqueous phase into a moderate uniform size to obtain a reaction system. The reaction system was heated to 75°C, and reacted at this temperature for 2 h to obtain a prepolymer.

[0042] A2, 250 g of the prepolymer and 10 g of glycidyl methacrylate were added to a four-necked flask, and the four-necked flask was heated to 90°C, and reacted at this temperature for 2 h, and then the reaction was stopped and cooled to room temperature. The product was filtered with a Buchner funnel, and then washed with deionized water three times to obtain a beaded resin; the beaded resin was dried in an oven at 80°C to a constant weight to obtain a polymeric sphere.

[0043] A3, 3 g of sodium sulfamate was dissolved in 20 mL of water, and then 1.5 g of aluminum chloride was added and uniformly mixed to obtain a mixture. The mixture was heated to 80°C, and then 0.1 mol / L NaOH solution was added dropwise to adjust the pH value of the mixture to 8. 250 g of the polymeric sphere was added to 20 g of the mixture, and reacted at this temperature for 15 h, and then cooled to room temperature to obtain a product. The product was filtered with a Buchner funnel, and then washed with deionized water three times, and then dried in an oven at 80°C to a constant weight to obtain a strong acid solid catalyst.

[0044] Example 2

[0045] The present embodiment provides a preparation method of a strong acid solid catalyst for synthesizing an activated catalyst for methyl p-tert-butylbenzoate, comprising the following steps:

[0046] A1, in a 500 mL four-necked flask equipped with a stirrer, a condenser and a thermometer, 200 mL of deionized water was added, followed by 0.025 g of gelatin, and stirred until the gelatin was completely dissolved in the deionized water to obtain a mixed solution; then 1 mol / L NaOH solution was added dropwise to adjust the pH value of the mixture to 7 to obtain an aqueous phase. 30 g of divinylbenzene monomer, 25 g of glyceryl trimethacrylate and 0.4 g of initiator azobisisobutyronitrile were mixed to obtain an oil phase mixture. 55 g of the oil phase mixture was added dropwise to 200 g of the aqueous phase to disperse the oil phase monomer droplets in the aqueous phase into a moderate uniform size to obtain a reaction system. The reaction system was heated to 78°C, and reacted at this temperature for 2.5 h to obtain a prepolymer.

[0047] A2, 250g of the prepolymer and 20g of glycidyl methacrylate were added to a four-necked flask, which was then heated to 95°C, and the reaction was maintained at this temperature for 4h, after which the reaction was stopped and the flask was cooled to room temperature. The product was filtered through a Buchner funnel and washed three times with deionized water, and the resulting bead resin was dried in an oven at 80°C to constant weight, thereby obtaining the polymerized spheres.

[0048] A3, 4g of sodium sulfamate was dissolved in 20mL of water, and 1.8g of aluminum chloride was added to the solution to obtain a mixture. The mixture was heated to 90°C, and 0.1mol / L NaOH solution was added dropwise to adjust the pH of the mixture to 9. 230g of the polymerized spheres was added to 20g of the mixture, and the reaction was maintained at this temperature for 18h, after which the reaction was stopped and the mixture was cooled to room temperature. The product was filtered through a Buchner funnel and washed three times with deionized water, and the resulting strong-acid solid catalyst was dried in an oven at 80°C to constant weight.

[0049] Example 3

[0050] The present example provides a method for preparing a strong-acid solid catalyst for synthesizing an activated catalyst for methyl p-tert-butylbenzoate, which comprises the following steps:

[0051] A1, 200mL of deionized water was added to a 500mL four-necked flask equipped with a stirrer, a condenser and a thermometer, and then 0.03g of gelatin was added and stirred until the gelatin was completely dissolved in the deionized water to obtain a mixture. 1mol / L NaOH solution was added dropwise to adjust the pH of the mixture to 7 to obtain an aqueous phase. 30g of divinylbenzene monomer, 30g of glyceryl trimethacrylate and 0.5g of initiator azobisisobutyronitrile were mixed to obtain an oil phase mixture. 60g of the oil phase mixture was added dropwise to 200g of the aqueous phase, and the oil phase monomer droplets were dispersed in the aqueous phase to obtain a reaction system. The reaction system was heated to 80°C, and the reaction was maintained at this temperature for 3h to obtain a prepolymer.

[0052] A2, 250g of the prepolymer and 20g of glycidyl methacrylate were added to a four-necked flask, which was then heated to 95°C, and the reaction was maintained at this temperature for 4h, after which the reaction was stopped and the flask was cooled to room temperature. The product was filtered through a Buchner funnel and washed three times with deionized water, and the resulting bead resin was dried in an oven at 80°C to constant weight, thereby obtaining the polymerized spheres.

[0053] A3, 5g of sodium sulfamate is dissolved in 20mL of water, then 2.5g of aluminum chloride is added and mixed uniformly to obtain a mixture. The mixture is heated to 100°C, and then 0.1 mol / L NaOH solution is added dropwise to adjust the pH value of the mixture to 10. 200g of polymeric spheres is added to 20g of the mixture, and the reaction is kept for 20h, and then cooled to room temperature. The mixture is filtered by a Buchner funnel, then washed with deionized water for three times, and then dried in an oven at 80°C until the weight is constant to obtain a strong-acid solid catalyst.

[0054] Example 4

[0055] The present example provides a preparation method of a modified molecular sieve for an activated catalyst for synthesizing methyl p-tert-butylbenzoate, comprising the following steps:

[0056] B1, 5.00g of ZSM-5 molecular sieve is accurately weighed, and then the above-mentioned molecular sieve solid is added to 0.5mol / L, 100mL of H2SO4 solution for immersion for 30min, and then filtered to collect the solid to obtain an acidified molecular sieve.

[0057] B2, 17g of toluene diisocyanate and 5g of trifluoroethanol are mixed uniformly to obtain a polyester prepolymer solution. Then, 2g of the acidified molecular sieve and 50mL of the polyester prepolymer solution are mixed, and magnetically stirred until uniformly mixed to obtain a polyester suspension; 0.5g of the curing agent methyl isobutyl ketone peroxide is added to 45mL of the polyester suspension, and the stirring is continued for 5min; after the stirring is completed, the mixture is poured into a rubber mold for vacuum degassing, and then cured at 70°C for 3h to synthesize the modified molecular sieve.

[0058] Example 5

[0059] The present example provides a preparation method of a modified molecular sieve for an activated catalyst for synthesizing methyl p-tert-butylbenzoate, comprising the following steps:

[0060] B1, 8.00g of ZSM-5 molecular sieve is accurately weighed, and then the above-mentioned molecular sieve solid is added to 0.8mol / L, 100mL of H2SO4 solution for immersion for 50min, and then filtered to collect the solid to obtain an acidified molecular sieve.

[0061] B2, 25g of toluene diisocyanate and 8g of trifluoroethanol are mixed uniformly to obtain a polyester prepolymer solution. Then, 3g of the acidified molecular sieve and 50mL of the polyester prepolymer solution are mixed, and magnetically stirred until uniformly mixed to obtain a polyester suspension; 0.5g of the curing agent methyl isobutyl ketone peroxide is added to 48mL of the polyester suspension, and the stirring is continued for 6min; after the stirring is completed, the mixture is poured into a rubber mold for vacuum degassing, and then cured at 75°C for 3.5h to synthesize the modified molecular sieve.

[0062] Example 6

[0063] The embodiment provides a preparation method of a modified molecular sieve for synthesizing an activated catalyst for methyl p-t-butylbenzoate, and comprises the following steps:

[0064] B1, 10.00g of ZSM-5 molecular sieve is accurately weighed, and then the molecular sieve solid is immersed in a 1mol / L, 100mL H2SO4 solution for 60min, and then filtered to collect the solid to obtain an acidified molecular sieve.

[0065] B2, 35g of toluene diisocyanate and 10g of trifluoroethanol are uniformly mixed to obtain a polyester prepolymer solution. Then, 5g of the acidified molecular sieve and 50mL of the polyester prepolymer solution are mixed, and magnetic stirring is performed until uniform mixing to obtain a polyester suspension; 0.5g of a curing agent, methyl isobutyl ketone peroxide, is added to the 50mL polyester suspension, and stirring is continued for 10min; after the stirring is completed, the mixture is poured into a rubber mold for vacuum degassing, and curing is performed at 80℃ for 4h to synthesize the modified molecular sieve.

[0066] Example 7

[0067] The embodiment provides a preparation method of an activated catalyst for synthesizing methyl p-t-butylbenzoate, and comprises the following steps:

[0068] S1, 10g of N-methyl morpholine, 15mL of n-butyl bromide and 50mL of acetone are added to a 250mL beaker, and stirring is performed at 45℃ until white solids are precipitated. The solids are vacuum filtered and dried to obtain an intermediate. Under a nitrogen atmosphere, 50mL of deionized water, 10g of the intermediate, 2.35g of MgCl2 and 1g of AlCl3 are added to a 250mL three-neck flask, and uniformly mixed to obtain a reactant. The reactant is reacted at 70℃ for 2h, and then water in the reactant is removed by rotary evaporation under reduced pressure to synthesize a metal ionic liquid.

[0069] S2, the strong-acid solid catalyst prepared in Example 1 and the modified molecular sieve prepared in Example 4 are mixed according to a mass ratio of 1:1 and added to a ball mill jar, and ball milling is performed at 200r / min for 20min to obtain a mixture. The mixture is immersed in the metal ionic liquid for 30min, and the mass ratio of the mixture to the metal ionic liquid is 1:10. After the immersion is completed, the mixture is filtered to obtain a solid. The solid is transferred to a tablet press for cold pressing to obtain a pre-pressed block. The pre-pressed block is transferred to a vacuum drying box and dried at 100℃ for 50min to obtain a dried block; after the dried block is naturally cooled to room temperature, an impregnated catalyst for synthesizing methyl p-t-butylbenzoate is synthesized.

[0070] Example 8

[0071] The embodiment provides a preparation method of an activated catalyst for synthesizing methyl p-t-butylbenzoate, and comprises the following steps:

[0072] S1, 12 g of N-methylmorpholine, 18 mL of n-bromobutane and 70 mL of acetone were added into a 250 mL beaker, stirred at 48℃ until white solid was precipitated. The solid was vacuum filtered and dried to obtain an intermediate. Under nitrogen atmosphere, 50 mL of deionized water, 12 g of the intermediate, 3.5 g of MgCl2 and 1.5 g of AlCl3 were added into a 250 mL three-necked flask, mixed to obtain a reactant. The reactant was reacted at 77℃ for 2.6 h, and then the water in the reactant was removed by rotary evaporation under reduced pressure to synthesize the metal ionic liquid.

[0073] S2, the strong acid solid catalyst prepared in Example 2 and the modified molecular sieve prepared in Example 5 were mixed in a mass ratio of 1:1 and added into a ball mill jar, ball-milled at 250 r / min for 26 min to obtain a mixture. The mixture was immersed in the metal ionic liquid for 50 min, and the mass ratio of the mixture to the metal ionic liquid was 1:12. After the immersion was completed, filtration was performed to obtain a solid. The solid was transferred to a tablet press for cold pressing to obtain a pre-pressed block. The pre-pressed block was transferred to a vacuum drying oven and dried at 105℃ for 55 min to obtain a dried block; after the dried block was naturally cooled to room temperature, an impregnated catalyst for synthesizing methyl p-tert-butylbenzoate was obtained.

[0074] Example 9

[0075] The present example provides a preparation method of an activated catalyst for synthesizing methyl p-tert-butylbenzoate, comprising the following steps:

[0076] S1, 15 g of N-methylmorpholine, 20 mL of n-bromobutane and 100 mL of acetone were added into a 250 mL beaker, stirred at 50℃ until white solid was precipitated. The solid was vacuum filtered and dried to obtain an intermediate. Under nitrogen atmosphere, 50 mL of deionized water, 15 g of the intermediate, 5.5 g of MgCl2 and 2 g of AlCl3 were added into a 250 mL three-necked flask, mixed to obtain a reactant. The reactant was reacted at 80℃ for 3 h, and then the water in the reactant was removed by rotary evaporation under reduced pressure to synthesize the metal ionic liquid.

[0077] S2, the strong acid solid catalyst prepared in Example 3 and the modified molecular sieve prepared in Example 6 were mixed in a mass ratio of 1:1 and added into a ball mill jar, ball-milled at 300 r / min for 30 min to obtain a mixture. The mixture was immersed in the metal ionic liquid for 60 min, and the mass ratio of the mixture to the metal ionic liquid was 1:15. After the immersion was completed, filtration was performed to obtain a solid. The solid was transferred to a tablet press for cold pressing to obtain a pre-pressed block. The pre-pressed block was transferred to a vacuum drying oven and dried at 100℃ for 50 min to obtain a dried block; after the dried block was naturally cooled to room temperature, an impregnated catalyst for synthesizing methyl p-tert-butylbenzoate was obtained.

[0078] Comparative Example 1

[0079] The difference between the present comparative example and Example 3 is that, in the synthesis of the strong acid solid catalyst, glyceryl trimethacrylate is replaced by the same mass of styrene in the preparation of the prepolymer in step A1.

[0080] Comparative Example 2

[0081] The difference between the present comparative example and Example 9 is that, in the synthesis of the modified molecular sieve, trifluoroethanol is replaced by the same mass of ethylene glycol.

[0082] Comparative Example 3

[0083] The difference between the present comparative example and Example 9 is that, in the synthesis of the active catalyst, magnesium chloride and aluminum chloride are replaced by the same molar amount of cobalt chloride hexahydrate and tin chloride.

[0084] Performance detection:

[0085] 1. The acid content of the strong acid solid catalysts prepared in Examples 1-3 and Comparative Example 1 was determined by n-butylamine titration, and the test results are shown in Table 1 below:

[0086] Table 1 - Performance detection data table of samples

[0087]

[0088] Data analysis: comparing and analyzing the data in Table 1 above, the strong acid solid catalysts prepared in Examples 1-3 have a higher acid content, but in Comparative Example 1, glyceryl trimethacrylate is replaced by the same mass of styrene, thereby reducing the number of double bonds in the prepared catalyst, reducing the number of grafted glycidyl methacrylate, and further reducing the number of epoxy groups that can react with sodium aminosulfate, thereby reducing the solid acid content of the prepared strong acid solid catalyst.

[0089] 2. In the industrial production of p-tert-butyl benzoic acid methyl ester using toluene and isobutene as raw materials, in the esterification stage, p-tert-butyl benzoic acid and methanol are reacted to synthesize p-tert-butyl benzoic acid methyl ester crude product, and the active catalysts prepared in Examples 7-9 and Comparative Examples 2-3 are sequentially added, to obtain p-tert-butyl benzoic acid methyl ester crude product. The amount ratio of p-tert-butyl benzoic acid, methanol and active catalyst is 1500 kg:75 kg:1.5 m 3 After one month of continuous process, the conversion rate of p-tert-butyl benzoic acid methyl ester synthesized by Examples 7-9 and Comparative Examples 2-3 was detected by acid-base titration method.

[0090] Table 2 - Performance detection data table of samples

[0091]

[0092] Data analysis: The conversion rate of methyl p-tert-butylbenzoate synthesized by the activated catalyst used in examples 7-9 of the present application is high, all reaching more than 99%. However, when the activated catalyst prepared in comparative example 2 is used to synthesize modified molecular sieves, ethylene glycol is used to replace the same amount of trifluoroethanol, which reduces the wear resistance and corrosion resistance of the synthesized modified molecular sieves. The activity of the activated catalyst prepared in comparative example 2 is significantly reduced after a period of continuous process, which is manifested as a significant decrease in the conversion rate of methyl p-tert-butylbenzoate.

[0093] In comparative example 3, the coordination metal aluminum and magnesium are replaced by cobalt and tin metal elements when synthesizing the active catalyst. In the present application, the catalytic activity of aluminum chloride and magnesium chloride is higher, which is manifested as a decrease in the conversion rate of the active catalyst synthesized in comparative example 3.

[0094] The above is only an example and description of the structure of the present application. Those skilled in the art can make various modifications or supplements to the described specific embodiments or use similar ways to replace them, as long as they do not deviate from the structure of the invention or exceed the scope defined by the claims.

[0095] In the description of the present specification, the description of the terms "one embodiment", "example", "specific example" and the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0096] The preferred embodiments of the present application disclosed above are only used to help explain the present application. The preferred embodiments do not describe all the details and limit the present application to the specific embodiments. Obviously, many modifications and changes can be made according to the content of the present specification. The present specification selects and describes these embodiments in order to better explain the principles and practical applications of the present application, so that those skilled in the art can well understand and utilize the present application. The present application is limited only by the claims and their entire scope and equivalents.

Claims

1. A method for preparing an activated catalyst for the synthesis of methyl p-tert-butylbenzoate, characterized in that, Includes the following steps: S1, a strong acid solid catalyst and modified molecular sieve are mixed and ball-milled to obtain a mixture; S2. The mixture is activated in a metal ion liquid, then filtered to obtain a solid; the solid is cold-pressed to obtain a pre-pressed block; the pre-pressed block is dried and then naturally cooled to obtain the activated catalyst for the synthesis of methyl p-tert-butylbenzoate. In step S1, the preparation method of the strongly acidic solid catalyst includes the following steps: A1. Gelatin is completely dissolved in deionized water to obtain a mixed solution. NaOH solution is then added dropwise to adjust the pH of the mixed solution to 7, resulting in an aqueous phase. Divinylbenzene, glyceryl trimethacrylate, and initiator are mixed to obtain an oil phase mixture. The oil phase mixture is added to the aqueous phase to obtain a reaction system. The reaction system is heated to 75-80℃ and reacted at this temperature for 2-3 hours to obtain a prepolymer. A2. Add glycidyl methacrylate to the prepolymer, then heat to 90-95℃, keep the reaction at this temperature for 2-4 hours, then stop the reaction, cool to room temperature, and then process to obtain polymer spheres. A3. Sodium aminosulfonate is first dissolved in water, then aluminum chloride is added and mixed well to obtain a mixture; the mixture is heated to 80-100℃, NaOH solution is added dropwise to adjust the pH of the mixture to 8-10, then polymerized spheres are added, and the reaction is kept at 80-100℃ for 15-20h. After post-processing, a strong acid solid catalyst is prepared. In step S1, the method for preparing the modified molecular sieve includes the following steps: B1. ZSM-5 molecular sieve was added to H2SO4 solution and soaked for 30-60 min, then filtered and the solid was collected to obtain acidified molecular sieve. B2, toluene diisocyanate and trifluoroethanol are mixed to obtain a polyester prepolymer solution; acidified molecular sieve and polyester prepolymer solution are mixed to obtain a polyester suspension; a curing agent is added to the polyester suspension, stirred, vacuum degassed, and cured at 70-80℃ for 3-4 hours to obtain a modified molecular sieve. In step S2, the preparation method of the metal ionic liquid includes the following steps: 10-15 g of N-methylmorpholin, 5-20 mL of n-butane bromide, and 50-100 mL of acetone were mixed and stirred to produce a white solid. The white solid was vacuum filtered and dried to obtain an intermediate. 50 mL of deionized water, 10-15 g of the intermediate, 2.35-5.5 g of MgCl2, and 1-2 g of AlCl3 were mixed to obtain the reactant. The reactant was reacted at 70-80 °C for 2-3 h, and then the water in the reactant was removed by rotary evaporation under reduced pressure to obtain a metal ion liquid.

2. The preparation method according to claim 1, characterized in that, In step A1, the ratio of gelatin to deionized water is 0.02-0.03g:150-200mL, and the initiator is azobisisobutyronitrile; the ratio of divinylbenzene, glyceryl trimethacrylate, and initiator is 30g:20-30g:0.3-0.5g; the ratio of oil phase mixture to aqueous phase is 50-60g:200g; in step A2, the ratio of prepolymer to glycidyl methacrylate is 250g:10-20g. The post-processing steps include: filtration using a Buchner funnel, followed by rinsing three times with deionized water to obtain bead-like resin; The bead-like resin was dried in an oven at 80°C to constant weight to obtain polymer spheres.

3. The preparation method according to claim 1, characterized in that, In step A3, the ratio of sodium aminosulfonate, water and aluminum chloride is 3-5g:20mL:1.5-2.5g, and the ratio of the mixture to the polymer spheres is 20g:200-250g. The post-processing steps include: filtration using a Buchner funnel, rinsing three times with deionized water, and then drying in an oven at 80℃ to constant weight to obtain a strongly acidic solid catalyst.

4. The preparation method according to claim 1, characterized in that, In step B1, the concentration of H2SO4 solution is 0.5-1 mol / L, and the ratio of ZSM-5 molecular sieve to H2SO4 solution is 5.00-10.00 g: 100 mL; in step B2, the ratio of toluene diisocyanate to trifluoroethanol is 17-35 g: 5-10 g, and the ratio of acidified molecular sieve to polyester prepolymer solution is 2-5 g: 50 mL; the curing agent is methyl isobutyl ketone peroxide, and the ratio of polyester suspension to curing agent is 45-50 mL: 0.5 g.

5. The preparation method according to claim 1, characterized in that, In step S1, the mass ratio of the strong acid solid catalyst to the modified molecular sieve is 1:1; the ball milling speed is 200-300 r / min and the ball milling time is 20-30 min.

6. The preparation method according to claim 1, characterized in that, In step S2, the drying temperature is 100-110℃ and the drying time is 50-60min.

7. An activating catalyst for the synthesis of methyl p-tert-butylbenzoate, characterized in that, It is prepared by the preparation method described in any one of claims 1-6.

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