Epoxidation catalyst as well as preparation method and application thereof

Abstract

The invention discloses an epoxidation catalyst as well as a preparation method and application thereof. The preparation method of the epoxidation catalyst comprises the following steps: preparing hollow silicon dioxide microspheres by using a template method, mixing and dispersing the hollow silicon dioxide microspheres and polystyrene microspheres, vertically immersing a quartz glass sheet into a solution, and standing to obtain a colloidal crystal film. And drying and roasting the film to obtain the three-dimensional ordered silicon dioxide template with vacancies. And immersing the template into the prepared silicon dioxide sol, standing and drying. And immersing, standing and drying. And then carrying out vapor deposition to load a titanium source, roasting, washing with water, and carrying out ammonium fluoride pretreatment to obtain the epoxidation catalyst. The catalyst has the characteristics of high activity and high selectivity especially for epoxidation of macromolecular olefin.

Description

Technical Field

[0001] The present invention relates to an epoxidation catalyst for olefins, and particularly to an epoxidation catalyst, a preparation method thereof and an application thereof. Background Art

[0002] In recent years, three-dimensional ordered macroporous (3DOM) materials have attracted wide attention. Due to its three-dimensional regular macroporous structure characteristics, it has broad application prospects in photonic crystals, novel macroporous catalysts, adsorbents, chromatographic materials or microbial carriers, etc. As a carrier, by loading specific active groups, functionalized 3DOM materials can be constructed. Not only the pore size is large and the reactants are easy to reach the active center, which can improve the catalytic conversion efficiency, but also the pore size distribution is uniform. For the catalytic conversion process of macromolecules or biomolecules, it is possible to achieve efficient selective separation and catalytic conversion. Therefore, the preparation of novel functionalized 3DOM materials and their related process applications are important topics in the research of 3DOM materials.

[0003] Epoxides are one of the important chemical raw materials. Due to its relatively active three-membered oxygen ring structure, it is easy to undergo ring-opening reactions or react with compounds containing functional groups such as alcohols and amines, and is widely used in the production of fine chemicals, food additives, pharmaceutical intermediates and chemical pesticides, etc. For example, propylene oxide is mainly used to manufacture chemical raw materials such as polyether polyols and propylene glycol. Polyether polyols can be used to produce polyurethane foams, which are widely used in the fields of automobiles, furniture, household appliances, etc. Taking styrene oxide as an example, it is a common resin additive and also an important intermediate for medicine, dyes and perfumes. Therefore, the research and development of olefin epoxidation reactions have important significance in the academic and industrial fields.

[0004] The two most important monomers in epoxides are ethylene oxide and propylene oxide, and their catalysts are mainly titanium silicalite molecular sieves. The US Patent US4410501A first disclosed the method for synthesizing titanium silicalite molecular sieve TS-1 by the classical hydrothermal crystallization method. This method mainly includes two steps: preparing the gel and crystallization. The specific steps are as follows: Put tetraethyl orthosilicate (TEOS), the silicon source, into a container protected by nitrogen and free of CO2, slowly add tetrapropylammonium hydroxide (TPAOH), the template agent, and then slowly drop tetraethyl titanate (TEOT), the titanium source. Stir for 1 h to obtain a reaction mixture containing silicon, titanium, and organic base. Heat, remove alcohol, add water, and crystallize at 175 °C for 10 days under stirring in an autogenous pressure reactor. Then, separate, wash, dry, and calcine to obtain the TS-1 molecular sieve. However, there are many factors affecting the insertion of titanium into the framework in this process. The conditions of hydrolysis, crystal nucleation, and crystal growth are not easy to control, and a certain amount of titanium fails to be effectively inserted into the molecular sieve framework and remains in the pores in the form of non-framework titanium. The generation of non-framework titanium not only reduces the number of catalytic active centers but also promotes the ineffective decomposition of hydrogen peroxide by non-framework titanium-silicon species, resulting in waste of raw materials. Therefore, the TS-1 molecular sieve synthesized by this method has deficiencies such as low catalytic activity, poor stability, and difficulty in reproducibility.

[0005] US Published Patents US6211388B1 and US5744619A disclose a method for preparing an epoxidation catalyst by the sol-gel method: dissolve the silicon source and the titanium source in an alcohol solvent respectively, and add a quaternary ammonium ion (such as cetyltrimethylammonium bromide) as the template agent. After hydrolysis, polymerization, and aging to form a gel, then perform high-temperature calcination, crushing and forming, and silanization treatment to obtain the catalyst. The titanium active species of this catalyst have poor dispersion on the SiO 2 surface and are prone to form free TiO 2 , resulting in the ineffective decomposition of the oxidant and reducing the selectivity of PO.

[0006] Chinese Patent CN112744837B discloses a method for preparing a titanium silicalite molecular sieve for macromolecular epoxides. The titanium silicalite molecular sieve prepared by this method using the sol-gel method is rich in titanium on the surface and has an appropriate mesoporous most probable pore diameter. When it is used in the process of oxidizing macromolecular olefins to produce epoxides, it can improve the raw material conversion rate and the selectivity of the target product. The most probable pore diameter of this catalyst is 15 - 35 nm. The macromolecular olefins used are cyclohexene, cyclooctene, styrene, or limonene, and it is not applicable to olefins with a larger carbon number. Summary of the Invention

[0007] To solve the above technical problems, the present invention first proposes a method for preparing an epoxidation catalyst. This method prepares hollow silica microspheres through a template method, then mixes them with polystyrene microspheres, prepares a colloidal crystal film through a crystal template method, and then uses this as a template to obtain three-dimensionally ordered silica as a catalyst support. This support has a rich pore network, with a macropore diameter of approximately 200 nm. Treatment with ammonium fluoride reduces the Si-OH on the catalyst surface, which can effectively reduce the steric hindrance in the pores, promote the diffusion of olefin reactants, improve the contact between titanium sites and olefin reactants, and thus enhance the activity of olefin epoxidation.

[0008] The present invention also proposes an epoxidation catalyst prepared by the above method.

[0009] The present invention also proposes the application of an epoxidation catalyst prepared by the above method in the catalytic epoxidation reaction of olefins. Especially for the epoxidation of macromolecular olefins, it has the characteristics of high activity and high selectivity.

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

[0011] A method for preparing an epoxidation catalyst, comprising the following steps:

[0012] 1) Using a polymer latex as a template agent, forming silica formed from a silicon source reagent on the template agent, and then dissolving the template agent to obtain hollow silica microspheres;

[0013] 2) Mixing the hollow silica microspheres and polystyrene microspheres according to a mass ratio of 1:(1 - 4), preferably 1:(2 - 3), adding water and fully dispersing to obtain a mixed solution; vertically immersing a quartz glass sheet into the mixed solution, standing still to obtain a colloidal crystal film; drying and calcining the film to obtain a three-dimensionally ordered silica template with vacancies;

[0014] 3) Mixing a silicon source reagent, ethanol, and hydrochloric acid to prepare a silica sol; immersing the three-dimensionally ordered silica template into the silica sol, standing still, and drying; then immersing again, standing still, and drying, repeating multiple times to obtain a catalyst support;

[0015] 4) Loading the catalyst support into a reactor, performing gas-phase deposition to load a titanium source, and then calcining and washing with water to obtain a catalyst precursor; pretreating the catalyst precursor with ammonium fluoride to obtain an epoxidation catalyst.

[0016] As a preferred embodiment of the present invention, the polymer latex is a polystyrene latex;

[0017] Preferably, the preparation method of the polystyrene latex is as follows:

[0018] Mix a functionalizing reagent, water, and styrene monomer, add ammonium persulfate, and obtain polystyrene latex; preferably, the functionalizing reagent is at least one of polyvinylpyrrolidone and polypropylene pyrrolidone; preferably, the mass ratio of the styrene monomer, water, and functionalizing reagent is 1:(5 - 15):(0.1 - 0.5), preferably 1:(8 - 12):(0.2 - 0.4); the amount of ammonium persulfate used is 0.01 - 0.1 times the mass of the styrene monomer, preferably 0.04 - 0.07 times.

[0019] More preferably, the functionalizing reagent, water, and styrene monomer are stirred and mixed at room temperature for 30 - 60 min, then heated to 60 - 90 °C, preferably 70 - 80 °C, add ammonium persulfate, and continue stirring and reacting for 6 - 12 h, preferably 8 - 10 h, to obtain polystyrene latex.

[0020] As a preferred embodiment of the present invention, the specific preparation method of step 1) is: mix the polymer latex, ammonia water, and ethanol, then add a silicon source reagent, stir and react, separate, wash, and dry to obtain hollow silica microspheres;

[0021] Preferably, the volume ratio of the polymer latex, ammonia water, ethanol, and silicon source reagent is 1:(0.1 - 1):(10 - 40):(0.5 - 4), preferably 1:(0.4 - 0.8):(20 - 30):(1 - 3);

[0022] Preferably, the reaction temperature is 60 - 80 °C, and the reaction time is 6 - 24 h;

[0023] Preferably, the silicon source reagent is at least one of tetraethyl orthosilicate, tetrapropyl orthosilicate, and tetrabutyl orthosilicate.

[0024] Preferably, the above separation method can be simple centrifugation separation. The separated solid is washed with ethanol multiple times, and then dried at 60 - 90 °C for 6 - 10 h, for example, to obtain hollow silica microspheres.

[0025] As a preferred embodiment of the present invention, in step 2), the dispersion is prepared by adding water and ultrasonically stirring to obtain a mixed solution with a mass ratio of 1 - 10 wt% based on the mass of the polystyrene microspheres.

[0026] As a preferred embodiment of the present invention, the standing temperature in step 2) is 40 - 50 °C, and the time is 36 - 72 h;

[0027] Preferably, the drying conditions of the film in step 2) are, for example, first drying at room temperature for 18 - 32 h, and then drying at 60 - 70 °C for 30 - 120 min. These can be routinely adjusted by those skilled in the art and will not be further elaborated.

[0028] Preferably, the calcination is carried out in an air atmosphere; the heating program for calcination is 1-2 °C / min. First, it is heated from room temperature to 300-400 °C and maintained for 2-3 h, then heated to 550-650 °C and maintained for 4-6 h. Finally, it is naturally cooled to room temperature.

[0029] As a preferred embodiment of the present invention, in step 3), the volume ratio of the silicon source reagent, ethanol, and hydrochloric acid is 1:(0.5-3):(0.2-1), preferably 1:(1-2):(0.4-0.8);

[0030] Preferably, the reaction conditions for preparing the silica sol in step 3) are: stirring and reacting at 50-60 °C for 30-180 min.

[0031] As a preferred embodiment of the present invention, in step 3), the three-dimensional ordered silica template is immersed in the silica sol for 10-20 min, filtered by suction and then dried. This operation is repeated 2-3 times to obtain the catalyst support, which is broken into particles with a particle size of 0.5-2 mm.

[0032] Preferably, the drying method of the solid after suction filtration can be drying in an oven at 60-70 °C for 40-120 min, which can be routinely adjusted by those skilled in the art.

[0033] As a preferred embodiment of the present invention, in step 4), the titanium source is titanium tetrachloride, and the mass ratio of the titanium source to the catalyst support is (0.05-0.5):1, preferably (0.1-0.3):1;

[0034] Preferably, in step 4), the vapor deposition temperature is 150-350 °C and the time is 2-4 h;

[0035] Preferably, in step 4), the calcination temperature is 500-750 °C and the calcination time is 4-12 h;

[0036] Preferably, in step 4), the water washing temperature is 200-400 °C and the water washing time is 4-12 h; the amount of water added can be 1-5 times the mass of the titanium source.

[0037] Preferably, the conditions for ammonium fluoride pretreatment in step 4) are: preparing a methanol solution of ammonium fluoride with a mass concentration of 5-40%, preferably 10-30%. The catalyst precursor is immersed in the above methanol solution of ammonium fluoride, and the dosage ratio of the two, calculated by the mass ratio of the catalyst to the ammonium fluoride solution, is, for example, 1:(2-30), preferably 1:(4-20), and treated at 30-50 °C for 30-120 min. After treatment, it is filtered and dried at 50-70 °C for 30-120 min to obtain the epoxidation catalyst.

[0038] An epoxidation catalyst prepared by the method described above.

[0039] Use of an epoxidation catalyst prepared by the method described above in the catalytic epoxidation reaction of olefins.

[0040] The positive effects of the present invention are as follows:

[0041] 1. A three-dimensionally ordered silica support is prepared, which has a rich pore network. While providing more active centers, it increases the adaptability of the catalyst and enables the epoxidation of larger molecular olefins.

[0042] 2. By pretreating the catalyst with ammonium fluoride, the mutual condensation between adjacent silanol groups on the silica surface is induced to form siloxane bridge bonds without introducing new groups on the surface. The self-condensation effect between silanol groups can effectively reduce the steric hindrance of the adsorption and diffusion of olefin reactants, thereby improving the desorption of reactants while increasing the accessibility of titanium sites. Therefore, not only can the selectivity of the epoxidation product be improved by enhancing the hydrophobicity of the titanium silicalite, but also the activity of the olefin epoxidation can be increased by exposing more titanium sites. Specific Embodiments

[0043] The present invention will be further described below through specific examples. The examples described in the present invention are only for the illustration of the present invention and do not limit the scope of the present invention.

[0044] The main raw material information in the following examples of the present invention is as follows. Other raw materials and reagents can be obtained through commercial channels without special instructions.

[0045] Styrene monomer, Aladdin reagent;

[0046] Polystyrene microspheres (particle size 9.0 - 9.9 μm), Aladdin reagent;

[0047] Polyvinylpyrrolidone, polypropylene pyrrolidone, Aladdin reagent;

[0048] Ammonium persulfate, Aladdin reagent;

[0049] Tetraethyl orthosilicate, tetrapropyl orthosilicate, tetrabutyl orthosilicate, Aladdin reagent;

[0050] Ammonia water, Innochem reagent;

[0051] Methanol, ethanol, Innochem reagent;

[0052] Hydrochloric acid, Innochem reagent;

[0053] Titanium tetrachloride, Aladdin reagent;

[0054] Ammonium fluoride, Aladdin reagent;

[0055] Hydrochloric acid, hydrochloric acid solution with a concentration of 17 wt%;

[0056] The gas chromatography analysis conditions used in the examples of the present invention are as follows: Agilent DB-5 chromatographic column, injection port temperature: 270 °C; detector temperature: 270 °C; H 2 Flow rate: 35 ml / min; air flow rate: 350 ml / min. The column oven temperature program is: initial temperature -100 °C, heating rate 20 °C / min, hold for 1 min; 100 - 270 °C, heating rate 15 °C / min, hold for 8 min.

[0057] Example 1

[0058] Add 10 g of styrene monomer, 50 g of water, and 1 g of polyvinylpyrrolidone to a 150 ml three-necked round-bottom flask. Stir at room temperature for 30 min, then raise the temperature to 60 °C, and dropwise add 6 ml of ammonium persulfate aqueous solution (containing 0.1 g of ammonium persulfate) under stirring, and continue to react for 12 h to obtain polystyrene latex. Take another 500 ml three-necked round-bottom flask, add 20 ml of polystyrene latex, 2 ml of ammonia water, and 200 ml of ethanol to it. Stir and raise the temperature to 60 °C, dropwise add 10 ml of tetraethyl orthosilicate, and continue to react for 24 h. Centrifuge the obtained sample, wash the separated product three times with ethanol, and dry it in an oven at 60 °C for 10 h to obtain hollow silica microspheres.

[0059] Take 10 g of hollow silica microspheres and 10 g of polystyrene microspheres, add 980 g of deionized water, and ultrasonically disperse them evenly in a weighing bottle. Vertically immerse a clean and dry quartz glass sheet with a size of 30 mm × 30 mm into the solution, and let it stand in a constant temperature and humidity chamber. The standing temperature is 40 °C, the humidity is 60%, and the time is 72 h. After standing, take out the glass and dry it at room temperature for 18 h, and then dry it at 60 °C for 120 min. Put the dried colloidal crystal film into a muffle furnace and calcine it in an air atmosphere. The temperature program is to rise from room temperature to 300 °C at 1 °C / min, hold for 3 h, then rise to 550 °C at 1 °C / min, hold for 6 h, and naturally cool to room temperature to obtain a three-dimensional ordered silica template with vacancies.

[0060] Take a 300 ml round-bottom flask, add 100 ml of tetraethyl orthosilicate, 50 ml of ethanol, and 20 ml of hydrochloric acid, and stir and react at 50 °C for 180 min to obtain silica sol. Put the three-dimensional ordered silica template into the silica sol, soak it for 10 min, take it out after filtering and drying in an oven at 60 °C for 120 min. Repeat this operation 3 times to obtain a catalyst support, and crush it into particles with a size of 0.5 - 2 mm.

[0061] Load 10 g of catalyst support into the reaction tube of the chemical vapor deposition apparatus, heat it to 150 °C, add 0.5 g of titanium tetrachloride for chemical vapor deposition, with a deposition time of 2 h. After deposition, purge with nitrogen for 1 h. Then heat it to 500 °C and calcine for 12 h. Cool it to 200 °C, add 0.5 g for water washing, with a water washing time of 12 h, and then cool it to room temperature to obtain the catalyst precursor. Take a 100 ml round-bottom flask, add 20 g of 40 wt% ammonium fluoride methanol solution, place the catalyst precursor in it, and treat it at 30 °C for 120 min. Filter, dry it at 50 °C for 120 min to obtain the epoxidation catalyst A.

[0062] Example 2

[0063] Add 10 g of styrene monomer, 150 g of water, and 5 g of polyvinylpyrrolidone to a 300 ml three-necked round-bottom flask. Stir at room temperature for 60 min, then raise the temperature to 90 °C, and dropwise add 60 ml of ammonium persulfate aqueous solution (containing 1 g of ammonium persulfate) under stirring, and continue to react for 6 h to obtain polystyrene latex. Take another 2000 ml three-necked round-bottom flask, add 20 ml of polystyrene latex, 20 ml of ammonia water, and 800 ml of ethanol to it. Stir and heat to 80 °C, dropwise add 10 ml of tetraethyl orthosilicate, and continue to react for 6 h. Centrifuge the obtained sample, wash the separated layer three times with ethanol, and dry it in an oven at 90 °C for 6 h to obtain hollow silica microspheres.

[0064] Take 20 g of hollow silica microspheres and 80 g of polystyrene microspheres, add 700 g of deionized water, ultrasonically disperse them evenly in a weighing bottle, vertically immerse a clean and dry quartz glass sheet with a size of 30 mm × 30 mm into the solution, and let it stand in a constant temperature and humidity chamber. The standing temperature is 50 °C, the humidity is 50%, and the time is 36 h. After standing, take out the glass and dry it at room temperature for 32 h, and then dry it at 70 °C for 30 min. Put the dried colloidal crystal film into a muffle furnace and calcine it in an air atmosphere. The heating program is to rise from room temperature to 400 °C at 2 °C / min, hold for 2 h, then rise to 650 °C at 2 °C / min, hold for 4 h, and naturally cool to room temperature to obtain a three-dimensional ordered silica template with vacancies.

[0065] Take a 300 ml round-bottom flask, add 50 ml of tetraethyl orthosilicate, 150 ml of ethanol, and 50 ml of hydrochloric acid, stir and react at 60 °C for 30 min to obtain silica sol. Put the three-dimensional ordered silica template into the silica sol, soak it for 20 min, take it out after filtering and drying it in an oven at 70 °C for 40 min. Repeat this operation 2 times to obtain the catalyst support, and crush it into particles with a size of 0.5 - 2 mm.

[0066] Load 20 g of the catalyst support into the reaction tube of the chemical vapor deposition apparatus, heat it up to 350 °C, add 10 g of titanium tetrachloride for chemical vapor deposition, and the deposition time is 4 h. After the deposition is completed, purge with nitrogen for 1 h. Then heat it up to 750 °C and calcine for 4 h. Cool down to 400 °C, add 50 g for water washing, and the water washing time is 4 h. Then cool it down to room temperature to obtain the catalyst precursor. Take a 1000 ml round-bottom flask, add 600 g of 5 wt% ammonium fluoride methanol solution, place the catalyst precursor in it and treat it at 50 °C for 30 min, filter, and dry it at 70 °C for 30 min to obtain the epoxidation catalyst B.

[0067] Example 3

[0068] Add 10 g of styrene monomer, 80 g of water, and 2 g of polyvinylpyrrolidone to a 200 ml three-necked round-bottom flask. Stir at room temperature for 40 min, then raise the temperature to 70 °C, and dropwise add 24 ml of ammonium persulfate aqueous solution (containing 0.4 g of ammonium persulfate) under stirring, and continue the reaction for 10 h to obtain polystyrene latex. Take another 1000 ml three-necked round-bottom flask, add 20 ml of polystyrene latex, 8 ml of ammonia water, and 400 ml of ethanol to it. Stir and heat up to 70 °C, dropwise add 20 ml of propyl orthosilicate, and continue the reaction for 12 h. Centrifuge the obtained sample, wash the separated layer three times with ethanol, and dry it in an oven at 70 °C for 10 h to obtain hollow silica microspheres.

[0069] Take 15 g of hollow silica microspheres and 30 g of polystyrene microspheres, add 555 g of deionized water, ultrasonically disperse them evenly in a weighing bottle, vertically immerse a clean and dry quartz glass sheet with a size of 30 mm × 30 mm into the solution, and let it stand in a constant temperature and humidity chamber. The standing temperature is 45 °C, the humidity is 60%, and the time is 48 h. After standing, take out the glass and dry it at room temperature for 24 h, and then dry it at 65 °C for 60 min. Put the dried colloidal crystal film into a muffle furnace and calcine it in an air atmosphere. The heating program is to rise from room temperature to 350 °C at 2 °C / min, hold for 2.5 h, then rise to 600 °C at 1.5 °C / min, hold for 5 h, and naturally cool to room temperature to obtain a three-dimensional ordered silica template with vacancies.

[0070] Take a 500 ml round-bottom flask, add 50 ml of propyl orthosilicate, 50 ml of butyl orthosilicate, 100 ml of ethanol, and 40 ml of hydrochloric acid, stir and react at 55 °C for 60 min to obtain silica sol. Put the three-dimensional ordered silica template into the silica sol, soak it for 15 min, filter it by suction, take it out after drying in an oven at 65 °C for 60 min. Repeat this operation 3 times to obtain the catalyst support, and crush it into particles with a size of 0.5 - 2 mm.

[0071] Load 15 g of catalyst support into the reaction tube of the vapor deposition apparatus, heat up to 180 °C, add 1.5 g of titanium tetrachloride for vapor deposition, and the deposition time is 3 h. After deposition, purge with nitrogen for 1 h. Then heat up to 600 °C and calcine for 8 h. Cool down to 300 °C, add 3 g for water washing, and the water washing time is 6 h. Then cool down to room temperature to obtain the catalyst precursor. Take a 200 ml round-bottom flask, add 60 g of 30 wt% ammonium fluoride methanol solution, place the catalyst precursor in it and treat at 40 °C for 60 min, filter, and dry at 60 °C for 60 min to obtain the epoxidation catalyst C.

[0072] Example 4

[0073] Add 10 g of styrene monomer, 120 g of water, and 4 g of polyvinylpyrrolidone to a 300 ml three-necked round-bottom flask. Stir at room temperature for 40 min, then raise the temperature to 80 °C, and gradually add 42 ml of ammonium persulfate aqueous solution (containing 0.7 g of ammonium persulfate) dropwise under stirring, and continue to react for 8 h to obtain polystyrene latex. Take another 2000 ml three-necked round-bottom flask, add 20 ml of polystyrene latex, 16 ml of ammonia water, and 600 ml of ethanol to it. Stir and heat up to 65 °C, and gradually add 30 ml of propyl orthosilicate and 30 ml of butyl orthosilicate dropwise, and continue to react for 18 h. Centrifuge the obtained sample to separate, wash the separated layer three times with ethanol, and dry in an oven at 80 °C for 8 h to obtain hollow silica microspheres.

[0074] Take 10 g of hollow silica microspheres and 30 g of polystyrene microspheres, add 335 g of deionized water, and ultrasonically disperse them evenly in a weighing bottle. Vertically immerse a clean and dry quartz glass sheet with a size of 30 mm × 30 mm into the solution, and let it stand in a constant temperature and humidity chamber. The standing temperature is 45 °C, the humidity is 55%, and the time is 60 h. After standing, take out the glass and dry it at room temperature for 28 h, and then dry it at 60 °C for 90 min. Put the dried colloidal crystal film into a muffle furnace and calcine it in an air atmosphere. The heating program is to rise from room temperature to 400 °C at 2 °C / min, hold for 2 h, then rise to 620 °C at 1.5 °C / min, hold for 4.5 h, and naturally cool to room temperature to obtain a three-dimensional ordered silica template with vacancies.

[0075] Take a 500 ml round-bottom flask, add 25 ml of tetraethyl orthosilicate, 25 ml of tetrabutyl orthosilicate, 250 ml of ethanol, and 40 ml of hydrochloric acid, and stir and react at 53 °C for 120 min to obtain silica sol. Put the three-dimensional ordered silica template into the silica sol, soak it for 18 min, take it out after suction filtration and drying in an oven at 67 °C for 50 min. Repeat this operation 3 times to obtain the catalyst support, and crush it into particles with a size of 0.5 - 2 mm.

[0076] Load 15 g of catalyst support into the reaction tube of the vapor deposition apparatus, heat it up to 300 °C, add 4.5 g of titanium tetrachloride for vapor deposition, and the deposition time is 2.5 h. After the deposition is completed, purge with nitrogen for 1 h. Then heat it up to 700 °C and calcine for 6 h. Cool down to 250 °C, add 18 g for water washing, and the water washing time is 8 h. Then cool it down to room temperature to obtain the catalyst precursor. Take a 500 ml round-bottom flask, add 300 g of 15 wt% ammonium fluoride methanol solution, place the catalyst precursor in it and treat it at 35 °C for 80 min, filter, and dry it at 55 °C for 80 min to obtain the epoxidation catalyst D.

[0077] Example 5

[0078] Add 10 g of styrene monomer, 10 g of water, and 3 g of polyvinylpyrrolidone to a 300 ml three-necked round-bottom flask. Stir at room temperature for 45 min, then raise the temperature to 75 °C, and dropwise add 33 ml of ammonium persulfate aqueous solution (containing 0.55 g of ammonium persulfate) under stirring, and continue to react for 9 h to obtain polystyrene latex. Take another 1000 ml three-necked round-bottom flask, add 20 ml of polystyrene latex, 12 ml of ammonia water, and 500 ml of ethanol to it. Stir and heat up to 65 °C, and dropwise add 20 ml of tetraethyl orthosilicate and 20 ml of tetrabutyl orthosilicate, and continue to react for 15 h. Centrifuge the obtained sample, wash the separated layer three times with ethanol, and dry it in an oven at 80 °C for 9 h to obtain hollow silica microspheres.

[0079] Take 20 g of hollow silica microspheres and 50 g of polystyrene microspheres, add 763 g of deionized water, disperse them evenly by ultrasonic in a weighing bottle, vertically immerse a clean and dry quartz glass sheet with a size of 30 mm × 30 mm into the solution, and let it stand in a constant temperature and humidity chamber. The standing temperature is 45 °C, the humidity is 50%, and the time is 70 h. After standing, take out the glass and dry it at room temperature for 30 h, and then dry it at 80 °C for 75 min. Put the dried colloidal crystal film into a muffle furnace and calcine it in an air atmosphere. The heating program is to rise from room temperature to 380 °C at 2 °C / min, hold for 2 h, then rise to 600 °C at 1.5 °C / min, hold for 4 h, and naturally cool to room temperature to obtain a three-dimensional ordered silica template with vacancies.

[0080] Take a 500 ml round-bottom flask, add 75 ml of tetraethyl orthosilicate, 25 ml of tetrapropyl orthosilicate, 150 ml of ethanol, and 60 ml of hydrochloric acid, stir and react at 50 °C for 90 min to obtain silica sol. Put the three-dimensional ordered silica template into the silica sol, soak it for 15 min, take it out after filtering and drying it in an oven at 65 °C for 80 min. Repeat this operation 3 times to obtain the catalyst support, and crush it into particles with a size of 0.5 - 2 mm.

[0081] Load 15 g of catalyst support into the reaction tube of the vapor deposition apparatus, heat it up to 250 °C, add 3 g of titanium tetrachloride for vapor deposition, and the deposition time is 2.5 h. After the deposition is completed, purge with nitrogen for 1 h. Then heat it up to 650 °C and calcine for 7 h. Cool it down to 300 °C, add 9 g of water for water washing, and the water washing time is 7 h. Then cool it down to room temperature to obtain the catalyst precursor. Take a 500 ml round-bottom flask, add 180 g of 15 wt% ammonium fluoride methanol solution, place the catalyst precursor in it and treat it at 35 °C for 70 min, filter, and dry it at 55 °C for 70 min to obtain the epoxidation catalyst E.

[0082]

Comparative Example 1

[0083] Prepare the epoxidation catalyst WHP-1:

[0084] Add 50 kg of SiO 2 support into a tubular reactor with an inner diameter of 400 mm, set the heating furnace temperature to 350 °C, keep it at a constant temperature for 20 h, so that the temperature of the silica gel bed reaches 350 °C after equilibrium, treat it at 350 °C for 5 h, and cool it down after the treatment is completed; after the treatment is completed, raise the reaction tube temperature to 200 °C, 650 °C, 300 °C and 180 °C in sequence, and carry out the Ti active center deposition process, calcination process, water treatment process and silanization treatment respectively to obtain the epoxidation catalyst WHP-1. Among them, the Ti center deposition process is to use N 2 mixed with TiCl 4 vapor and enter the reactor for reaction, and the dosage of TiCl 4 is 17 kg; the water vapor treatment process is to mix nitrogen and water vapor and enter the reactor, and the total water dosage is 20 kg; the silanization treatment process is to mix nitrogen and hexamethyldisilazane vapor and enter the reactor, and the dosage of the silanization reagent is 30 kg.

[0085]

Application Example

[0086] According to the following method, use the epoxidation catalysts provided in the above examples and comparative examples respectively to carry out the epoxidation reaction of decene, and carry out chromatographic analysis on the reaction products. The analysis results are shown in Table 1.

[0087] Take 10 g of the epoxidation catalyst and load it into the reactor for the epoxidation reaction of decene. The reaction temperature is 70 °C, the pressure is 4.0 MPa, the decene feed rate is 2 ml / min, and the cumene hydroperoxide feed rate is 0.7 ml / min.

[0088] Table 1. Analysis Results

[0089]

[0090]

[0091] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the method of the present invention, several improvements and supplements can be made, and these improvements and supplements should also be regarded as the protection scope of the present invention.

Claims

1. A preparation method of an epoxidation catalyst, characterized in that, it comprises the following steps: 1) Using a polymer latex as a template agent, making silica formed from a silicon source reagent coat on the template agent, and then dissolving the template agent to obtain hollow silica microspheres; 2) Mixing the hollow silica microspheres and polystyrene microspheres according to a mass ratio of 1:(1 - 4), adding water and fully dispersing to obtain a mixed solution; vertically immersing a quartz glass sheet into the mixed solution, standing still to obtain a colloidal crystal film; drying and calcining the film to obtain a three-dimensional ordered silica template; 3) Mixing a silicon source reagent, ethanol, and hydrochloric acid to prepare a silica sol; immersing the three-dimensional ordered silica template into the silica sol, standing still, and drying; then immersing again, standing still, and drying, repeating multiple times to obtain a catalyst support; 4) Loading the catalyst support into a reactor, performing gas-phase deposition to load a titanium source, and then calcining and washing with water to obtain a catalyst precursor; pretreating the catalyst precursor with ammonium fluoride to obtain an epoxidation catalyst.

2. The preparation method of the epoxidation catalyst according to claim 1, characterized in that, the polymer latex is a polystyrene latex; Preferably, the preparation method of the polystyrene latex is as follows: Mixing a functionalizing reagent, water, and styrene monomer, adding ammonium persulfate to obtain a polystyrene latex; preferably, the functionalizing reagent is at least one of polyvinylpyrrolidone and polypropylene pyrrolidone; preferably, the mass ratio of the styrene monomer, water, and functionalizing reagent is 1:(5 - 15):(0.1 - 0.5); the dosage of ammonium persulfate is 0.01 - 0.1 times the mass of the styrene monomer; More preferably, the functionalizing reagent, water, and styrene monomer are stirred and mixed at room temperature for 30 - 60 min, then heated to 60 - 90 °C, adding ammonium persulfate, and continuing to stir and react for 6 - 12 h to obtain a polystyrene latex.

3. The preparation method of the epoxidation catalyst according to claim 1 or 2, characterized in that, the specific preparation method of step 1) is: mixing the polymer latex, ammonia water, and ethanol, then adding a silicon source reagent, stirring and reacting, separating, washing, and drying to obtain hollow silica microspheres; Preferably, the volume ratio of the polymer latex, ammonia water, ethanol, and silicon source reagent is 1:(0.1 - 1):(10 - 40):(0.5 - 4); Preferably, the reaction temperature is 60 - 80 °C, and the reaction time is 6 - 24 h; Preferably, the silicon source reagent is at least one of tetraethyl orthosilicate, tetrapropyl orthosilicate, and tetrabutyl orthosilicate.

4. The preparation method of the epoxidation catalyst according to any one of claims 1 - 3, characterized in that, the dispersion in step 2) is to prepare a mixed solution with a mass ratio of 1 - 10 wt% based on the mass of the polystyrene microspheres by adding water and ultrasonic stirring.

5. The preparation method of the epoxidation catalyst according to any one of claims 1 - 4, characterized in that, the standing temperature in step 2) is 40 - 50 °C, and the time is 36 - 72 h; Preferably, the calcination is carried out in an air atmosphere; the heating program for calcination is 1 - 2 °C / min. First, it is heated from room temperature to 300 - 400 °C and maintained for 2 - 3 h, then heated to 550 - 650 °C and maintained for 4 - 6 h.

6. The method for preparing an epoxidation catalyst according to any one of claims 1 - 5, characterized in that in step 3), the volume ratio of the silicon source reagent, ethanol, and hydrochloric acid is 1:(0.5 - 3):(0.2 - 1); Preferably, the reaction conditions for preparing the silica sol in step 3) are: stirring and reacting at 50 - 60 °C for 30 - 180 min.

7. The method for preparing an epoxidation catalyst according to any one of claims 1 - 6, characterized in that in step 3), the three-dimensional ordered silica template is immersed in the silica sol for 10 - 20 min, filtered by suction and then dried. This operation is repeated 2 - 3 times to obtain a catalyst support, which is crushed into particles with a particle size of 0.5 - 2 mm.

8. The method for preparing an epoxidation catalyst according to any one of claims 1 - 7, characterized in that in step 4), the titanium source is titanium tetrachloride, and the mass ratio of the titanium source to the catalyst support is (0.05 - 0.5):1; Preferably, in step 4), the vapor deposition temperature is 150 - 350 °C and the time is 2 - 4 h; Preferably, in step 4), the calcination temperature is 500 - 750 °C and the calcination time is 4 - 12 h; Preferably, in step 4), the water washing temperature is 200 - 400 °C and the water washing time is 4 - 12 h; Preferably, the conditions for ammonium fluoride pretreatment in step 4) are: preparing a methanol solution of ammonium fluoride with a mass concentration of 5 - 40%, and immersing the catalyst precursor in the above methanol solution of ammonium fluoride and treating it at 30 - 50 °C for 30 - 120 min.

9. An epoxidation catalyst prepared by the method according to any one of claims 1 - 8.

10. Use of an epoxidation catalyst prepared by the method according to any one of claims 1 - 8 in the catalytic epoxidation reaction of olefins.

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