Ti-MWW molecular sieve catalyst, its preparation method and its use

Abstract

The present disclosure relates to a Ti-MWW molecular sieve catalyst, its preparation method, and its application. The X-ray photoelectron energy spectrum of the catalyst contains peaks at 458.9±0.2 eV and 464.8±0.2 eV, preferably 458.9±0.2 eV, 460.3±0.2 eV, 464.8±0.2 eV, and 465.9±0.2 eV. When used in olefin epoxidation, the Ti-MWW molecular sieve catalyst exhibits advantages such as high olefin conversion, high epoxide selectivity, and good catalytic stability.

Description

Detailed Description of the Invention

[0001] [Technical field] The present disclosure relates to the technical field of titanium silicate molecular sieve catalysts, in particular to Ti-MWW molecular sieve catalysts, their preparation and applications.

[0002] [Background technology] Epoxides are important organic chemicals, primarily ethylene oxide, propylene oxide, 1-pentene oxide, 1-hexene oxide, and others. Currently, epoxides are primarily produced by the selective oxidation of olefins. EniChem has developed a method for producing propylene oxide, known as the hydrogen peroxide-based propylene oxide (HPPO) process (see, for example, US Pat. No. 4,410,501A). This method uses TS-1 titanium silicate molecular sieves with an MFI structure as a catalyst to produce propylene oxide via the reaction of propylene and hydrogen peroxide in a methanol solvent. This process has the advantages of being environmentally friendly and having high raw material utilization, making it suitable for industrial use. However, the TS-1 molecular sieve has 10-membered ring channels approximately 0.5 nm in size, which makes the diffusion of large molecules unfavorable. This potentially presents a significant challenge in the epoxidation of cyclohexene, which has a relatively large molecular size. To address these challenges, Professor Wu Peng and his colleagues developed a new generation of titanium silicate molecular sieves (Ti-MWW) (see Journal of Catalysis, 2001, 202, 245). Compared with TS-1 molecular sieves, Ti-MWW molecular sieves not only exhibit higher olefin conversion rates, but also better epoxide selectivity.

[0003] Currently, industrial production of propylene oxide is primarily carried out in fixed-bed reactors. The titanium silicate molecular sieves obtained by hydrothermal methods are micron- or nanometer-sized powders with poor mechanical strength. If the titanium silicate molecular sieves are directly loaded into a fixed-bed reactor, they may become entrained in the reaction liquid during the reaction, potentially causing blockages. Furthermore, separating and recovering the titanium silicate molecular sieve powder from the reaction liquid after the reaction is extremely difficult. To ensure efficient and continuous fixed-bed reaction, the titanium silicate molecular sieve powder must be a catalyst with good mechanical strength.

[0004] CN1346705A proposes using small spheres with a certain mechanical strength as a support and shaping them by spheronization to enrich the surface of the spheres with titanium silicate molecular sieves. This improves the mechanical strength of the resulting catalyst. CN112354557A discloses the preparation and application of monolithic titanozeolite catalysts. Monolithic catalysts for continuous propylene epoxidation are prepared by mixing MWW titanium zeolite powder with an amorphous silicon binder and a polymeric pore former, adding water, stirring and kneading, mechanically molding, calcining, immersing in an aqueous solution of a cyclic nitrogen-containing organic complex, sealing, heating, filtering, drying, and calcining.

[0005] Overall, the prior art Ti-MWW molecular sieve catalysts, whether they contain binders or not, suffer from low mechanical strength and poor catalytic performance. Theoretically, the composition and structure of the prior art Ti-MWW molecular sieve catalysts can be modified to further improve their mechanical strength and catalytic performance. Therefore, there is a constant demand in the art for the development of Ti-MWW molecular sieve catalysts with high mechanical strength and good catalytic performance.

[0006] [Summary of the Invention] The present disclosure addresses the problems of the prior art, such as the low mechanical strength and poor catalytic performance of Ti-MWW molecular sieve catalysts. The present disclosure provides Ti-MWW molecular sieve catalysts, methods for preparing the same, and uses thereof. The Ti-MWW molecular sieve catalysts of the present disclosure contain titanium species in good condition and preferably have a perfect crystalline structure, thereby exhibiting the advantages of high mechanical strength and excellent catalytic performance.

[0007] To achieve the above-mentioned object, in a first aspect, the present disclosure provides a Ti-MWW molecular sieve catalyst, wherein the X-ray photoelectron energy spectrum of the catalyst comprises peaks at 458.9±0.2 eV and 464.8±0.2 eV, preferably 458.9±0.1 eV and 464.8±0.1 eV, and preferably the X-ray photoelectron energy spectrum of the catalyst comprises peaks at 458.9±0.2 eV, 460.3±0.2 eV, 464.8±0.2 eV and 465.9±0.2 eV, preferably 458.9±0.1 eV, 460.3±0.1 eV, 464.8±0.1 eV and 465.9±0.1 eV.

[0008] In a second aspect, the present disclosure provides a method for preparing a Ti-MWW molecular sieve catalyst, comprising the steps of: (1) molding and firing Ti-MWW molecular sieve powder, a binder, a pore-forming agent, and a fluoride to obtain a molded product; (2) a step of crystallizing the formed product of the step (1) in the presence of an organic amine solution to obtain a catalyst precursor A; (3) a step of treating the catalyst precursor A from the step (2) with an acid solution and calcining the treated catalyst precursor to obtain a catalyst precursor B; (4) A step of treating the catalyst precursor B from the step (3) with an organic amine solution to obtain a catalyst.

[0009] At the same time, the present disclosure provides a Ti-MWW molecular sieve catalyst prepared by the above-mentioned method.

[0010] Further provided in the present disclosure is the use of said Ti-MWW molecular sieve catalyst in the epoxidation of olefins.

[0011] By way of example, the disclosure may include the following items:

[0012] 1. A fully crystalline Ti-MWW molecular sieve catalyst, whose UV Raman spectrum is 343±4 cm -1 , 484±4cm -1 , 699±4cm -1 and 1097±4cm -1 Including the peak at 699±4cm -1 The intensity of the peak at 343±4 cm -1 and 1097±4 cm -1 The intensity of the peak at 343±4 cm -1 The fully crystalline Ti-MWW molecular sieve catalyst has an intensity of 0.5 to 10 times, preferably 2 to 10 times, that of the peak in

[0013] 2. The molecular sieve catalyst according to item 1, characterized in that the molar ratio of silicon to titanium in the molecular sieve catalyst is 10 to 200, preferably 25 to 100, the molecular sieve catalyst further contains at least one element selected from boron and aluminum, preferably boron, the molar ratio of boron to silicon in the molecular sieve catalyst is 0 to 0.1, preferably 0 to 0.03, more preferably 0.005 to 0.03, and the molar ratio of aluminum to silicon in the molecular sieve catalyst is 0 to 0.1, preferably 0 to 0.05.

[0014] 3. The molecular sieve catalyst has a particle size of 0.03 to 0.15 cm 3 / g, preferably 0.03 to 0.12 cm 3 / g, more preferably 0.05 to 0.10 cm 3 / g, wherein the ratio of the volume of the micropores to the total volume of the pores is 1% to 7.5%, preferably 1 to 6%, more preferably 1.7% to 5%.

[0015] 4. The molecular sieve catalyst according to item 1, characterized in that the molecular sieve catalyst has a mechanical strength of 30 to 90 N / cm, preferably 40 to 80 N / cm.

[0016] 5. A method for preparing a fully crystalline Ti-MWW molecular sieve catalyst, comprising the steps of: (1) Kneading, molding, and firing Ti-MWW molecular sieve powder, a binder, a pore-forming agent, and a fluoride to obtain a molded product; (2) a step of crystallizing the formed product of the step (1) in an organic amine solution to obtain a catalyst precursor A; (3) a step of treating the catalyst precursor A from the step (2) with an acid solution and calcining the treated catalyst precursor to obtain a catalyst precursor B; (4) A step of treating the catalyst precursor B of the step (3) with an organic amine solution to obtain the molecular sieve catalyst.

[0017] 6. The method according to item 5, wherein the binder in step (1) contains a silicon source and at least one selected from the group consisting of a boron source and an aluminum source, and wherein the binder contains components such that, on an oxide basis, SiO2, B2O3 and Al2O3 are in a molar ratio of 1:x:y, where x = 0 to 0.5, y = 0 to 0.5, and x + y = 0.02 to 1.

[0018] 7. The method according to item 6, wherein the silicon source is at least one selected from the group consisting of silica sol, sodium silicate, white carbon black, and ethyl orthosilicate, the boron source is at least one selected from the group consisting of boric acid, boron trioxide, and borate salts, and the aluminum source is at least one selected from the group consisting of aluminum oxide, aluminum hydroxide, sodium metaaluminate, aluminum nitrate, and aluminum sulfate.

[0019] 8. The method according to any one of items 5 to 7, wherein the pore-forming agent in the step (1) is at least one selected from the group consisting of sesbania powder, cellulose, chitosan, lignin, starch, polyethylene glycol, and triblock copolymers P123 and F127; the fluoride in the step (1) is at least one selected from the group consisting of sodium fluoride, potassium fluoride, and ammonium fluoride; and the mass ratio of the Ti-MWW molecular sieve powder, the binder, the pore-forming agent, and the fluoride among the raw materials in step (1) is 1:0.1-1.5:0.01-0.1:0.01-0.4.

[0020] 9. The method according to Item 5, wherein the step (2) of crystallizing in an environment of the organic amine solution comprises a step of crystallizing the shaped product of step (1) by placing it on the organic amine solution, wherein the shaped product is not in contact with the organic amine solution, the organic amine is at least one selected from the group consisting of piperidine and hexamethyleneimine, the concentration of the organic amine solution is 0.3 to 15 mol / L, the shaped product and the organic amine solution are in a mass ratio of 0.1 to 10:1, and the crystallization is carried out under conditions of a temperature of 130 to 190°C for 1 to 9 days.

[0021] 10. The method according to Item 5, wherein the step (3) of treating with an acid solution comprises a step of contacting and reacting the catalyst precursor A of the step (2) with the acid solution, wherein the acid solution is at least one selected from the group consisting of solutions of nitric acid, hydrochloric acid, sulfuric acid, formic acid, acetic acid, and oxalic acid, the concentration of the acid solution is 0.3 to 12 mol / L, the catalyst precursor A and the acid solution have a solid-liquid ratio by mass of 1:10 to 80, and the treatment with the acid solution is carried out under conditions of a temperature of 60 to 130°C for 4 to 48 hours.

[0022] 11. The method according to Item 5, wherein the step (4) of treating with an organic amine solution comprises a step of contacting and reacting the catalyst precursor B of the step (3), the fluoride, and the organic amine solution, wherein the fluoride is at least one selected from the group consisting of sodium fluoride, potassium fluoride, and ammonium fluoride, the organic amine is at least one selected from the group consisting of piperidine and hexamethyleneimine, the concentration of the organic amine solution is 0.3 to 15 mol / L, the catalyst precursor B, the fluoride, and the organic amine solution are in a mass ratio of 1:0.05 to 0.4:2 to 20, and the treatment with the organic amine solution is carried out under conditions of a temperature of 130 to 190°C for 4 to 48 hours.

[0023] 12. The method according to item 5, wherein the firing in step (1) is carried out under conditions of an oxygen-containing atmosphere at 450 to 650°C for 4 to 12 hours, and the firing in step (3) is carried out under conditions of an oxygen-containing atmosphere at 450 to 650°C for 4 to 12 hours.

[0024] 13. A molecular sieve catalyst prepared by the method according to any one of items 5 to 12.

[0025] 14. Use of the molecular sieve catalyst according to any one of items 1 to 4 or the molecular sieve catalyst according to item 13 in the epoxidation of an olefin.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] 1. The Ti-MWW molecular sieve catalyst of the present disclosure contains a large amount of well-formed titanium species, including modified exoframework hexacoordinated titanium species, or framework tetracoordinated titanium species and modified exoframework hexacoordinated titanium species. These well-formed titanium species provide catalysts with high catalytic performance. Furthermore, the Ti-MWW molecular sieve catalyst preferably has a fully crystalline structure. This means that the catalyst does not contain an amorphous binder. In other words, the binder is not present in amorphous form but is converted into the MWW molecular sieve, which then becomes part of the final catalyst, thereby resulting in a fully crystalline catalyst. On the one hand, the absence of an amorphous binder means that the effects of the amorphous binder on shielding the catalytic active centers and blocking the pores of the molecular sieve are avoided, thereby improving the activity and stability of the catalyst. On the other hand, the fully crystalline structure means that the mechanical strength is higher and the catalyst is less likely to be crushed or lost. When used in the epoxidation of olefins, the catalyst exhibits the advantages of high conversion to olefins, high selectivity to epoxides and good catalyst stability.

[0028] 2. In the preparation according to the present disclosure, the preferred amorphous binder contains a silicon source and a boron source, which can be efficiently converted into MWW molecular sieves, thereby providing the resulting catalyst with a perfect crystalline structure, thereby improving catalytic performance and mechanical strength. Furthermore, the preparation involves treating the crystallized catalyst precursor A with an acid solution and an organic amine solution, respectively, thereby effectively converting the titanium species in the Ti-MWW molecular sieve into well-defined titanium species, including modified extraframework hexacoordinated titanium species and, optionally, framework tetracoordinated titanium species. The preparation according to the present disclosure provides a Ti-MWW molecular sieve catalyst with excellent catalytic activity, selectivity, and stability.

[0029] 3. When used in the epoxidation of olefins, the catalyst according to the present disclosure exhibits excellent catalytic performance, high conversion rate to olefins, high selectivity to epoxides, and good catalytic stability, thereby having good applicability.

[0030] [Drawing Description] Figure 1 is the X-ray photoelectron spectrum of the Ti-MWW molecular sieve catalyst obtained in Example 1; Figure 2 is the UV Raman spectrum of the Ti-MWW molecular sieve catalyst obtained in Example 1; Figure 3 is the X-ray diffraction pattern of the Ti-MWW molecular sieve catalyst obtained in Example 1; FIG. 4 is a scanning electron microscope image of the Ti-MWW molecular sieve catalyst obtained in Example 1; Figure 5 is the X-ray photoelectron spectrum of the Ti-MWW molecular sieve catalyst obtained in Comparative Example 1; Figure 6 is the UV Raman spectrum of the Ti-MWW molecular sieve catalyst obtained in Comparative Example 1; Figure 7 is the X-ray diffraction pattern of the Ti-MWW molecular sieve catalyst obtained in Comparative Example 1; FIG. 8 is a scanning electron microscope image of the Ti-MWW molecular sieve catalyst obtained in Comparative Example 1; Figure 9 is the UV Raman spectrum of the Ti-MWW molecular sieve catalyst obtained in Comparative Example 2; Figure 10 is the UV Raman spectrum of the Ti-MWW molecular sieve catalyst obtained in Comparative Example 3; Figure 11 is the UV Raman spectrum of the Ti-MWW molecular sieve catalyst obtained in Comparative Example 4; Figure 12 is the UV Raman spectrum of the Ti-MWW molecular sieve catalyst obtained in Comparative Example 5; Figure 13 is the X-ray photoelectron spectrum of the Ti-MWW molecular sieve catalyst obtained in Comparative Example 6; Figure 14 is the UV Raman spectrum of the Ti-MWW molecular sieve catalyst obtained in Comparative Example 6; Figure 15 is the X-ray photoelectron spectrum of the Ti-MWW molecular sieve catalyst obtained in Comparative Example 7; FIG. 16 is a UV Raman spectrum of the Ti-MWW molecular sieve catalyst obtained in Comparative Example 7.

[0031] [Detailed explanation] In the present invention, percentages and ratios are by weight unless otherwise specified. Unless otherwise specified, throughout the specification and claims, the term "comprises" or variations thereof, such as "comprises" or "comprising" and others, shall be understood to include the steps or components set forth without excluding other steps or other components.

[0032] Except in the examples, numerical values ​​of all parameters in this specification are to be understood as being modified in all instances by the term "about," whether or not "about" is actually preceding the numerical value.

[0033] In one embodiment, the present disclosure provides a Ti-MWW molecular sieve catalyst, wherein the X-ray photoelectron energy spectrum of the catalyst comprises peaks at 458.9±0.2 eV and 464.8±0.2 eV, preferably 458.9±0.1 eV and 464.8±0.1 eV, and preferably the X-ray photoelectron energy spectrum of the catalyst comprises peaks at 458.9±0.2 eV, 460.3±0.2 eV, 464.8±0.2 eV and 465.9±0.2 eV, preferably 458.9±0.1 eV, 460.3±0.1 eV, 464.8±0.1 eV and 465.9±0.1 eV. The peaks at 460.3±0.2 eV and 465.9±0.2 eV are assigned to framework tetracoordinated titanium species, and the peaks at 458.9±0.2 eV and 464.8±0.2 eV are assigned to modified extraframework hexacoordinated titanium species.

[0034] As used herein, the term "Ti-MWW molecular sieve" refers to a titanium silicate molecular sieve having a three-dimensional MWW structure. Ti-MWW molecular sieves are commercially available or can be prepared according to methods known in the art. Typically, Ti-MWW molecular sieves are synthesized by a hydrothermal method using boric acid as a crystallization aid (see, for example, Journal of Physical Chemistry B, 2001, 105, 2897). Ti-MWW molecular sieves prepared by a hydrothermal method are referred to herein as "as-synthesized Ti-MWW molecular sieve powder." Methods have been proposed in the art to modify as-synthesized Ti-MWW molecular sieve powder to improve its catalytic performance. For example, as-synthesized Ti-MWW molecular sieve powder can be acid-treated (see, for example, Journal of Catalysis, 2001, 202, 245). The as-synthesized Ti-MWW molecular sieve powder after acid treatment is referred to herein as "Ti-MWW molecular sieve powder."

[0035] The titanium species in Ti-MWW molecular sieves may be in the form of tetracoordinated framework, extracoordinated framework, or titanium dioxide. The as-synthesized Ti-MWW molecular sieve powder prepared by the hydrothermal method may contain a small amount of tetracoordinated framework titanium species and a large amount of extracoordinated framework titanium species. The tetracoordinated framework titanium species are generally considered to be the catalytically active center in olefin epoxidation, the so-called "good-state titanium species." However, the extracoordinated framework titanium species and titanium dioxide are not catalytically active centers in olefin epoxidation and are the so-called "bad-state titanium species." Prior art efforts have attempted to convert the extracoordinated framework titanium species to tetracoordinated framework titanium species in order to improve the catalytic performance of catalysts. The aforementioned acid treatment of as-synthesized Ti-MWW molecular sieve powder is just such a conversion.

[0036] The present inventors have surprisingly found that exoframework hexacoordinated titanium species or tetracoordinated titanium species can be converted to modified exoframework hexacoordinated titanium species. The modification of titanium species can be reflected by peaks in the X-ray photoelectron spectrum of Ti-MWW molecular sieves. Before modification, the X-ray photoelectron spectrum of as-synthesized Ti-MWW molecular sieve powder may have peaks at 458.0±0.2 eV and 463.8±0.2 eV, which are assigned to exoframework hexacoordinated titanium species. The X-ray photoelectron spectrum of Ti-MWW molecular sieve powder may also have peaks at 460.3±0.2 eV and 465.9±0.2 eV, which are assigned to tetracoordinated titanium species. After modification, the X-ray photoelectron spectrum of the Ti-MWW molecular sieve powder can exhibit peaks at 458.9±0.2 eV and 464.8±0.2 eV, which are attributed to the modified exoframework hexacoordinated titanium species. The modified exoframework hexacoordinated titanium species also has excellent catalytic activity in olefin epoxidation. That is, it is also a titanium species in good condition, which can impart improved catalytic performance to the Ti-MWW molecular sieve catalyst of the present disclosure. The present invention was completed based on the above findings.

[0037] Preferably, the UV Raman spectrum of the catalyst contains a peak at 343±4 cm -1 , 484±4cm -1 , 699±4cm -1 and 1097±4cm -1 The peak is 699±4cm -1 The intensity of the peak at 343±4 cm -1 and 1097±4 cm -1 The intensity of the peak at 343±4 cm -1 Generally, the intensity of the peak at 343±4 cm is 0.5 to 10 times, preferably 2 to 10 times. -1 The peak at 484 ± 4 cm is assigned to the MWW skeleton. -1 and 1097±4cm -1 The peak at 699 ± 4 cm is assigned to framework tetracoordinate titanium species. -1The peaks at are assigned to extraframework hexacoordinated titanium species and / or modified extraframework hexacoordinated titanium species.

[0038] Preferably, the molar ratio of silicon to titanium in the catalyst (n Si / n Ti ) is 10 to 200, preferably 25 to 100 on an atomic basis.

[0039] Preferably, the catalyst may further contain at least one element of boron and aluminum, preferably boron. The molar ratio of boron to silicon (n B / n Si ) is 0 to 0.1, preferably 0 to 0.03, more preferably 0.005 to 0.03, on an atomic basis. The molar ratio of aluminum to silicon (n Al / n Si ) is 0 to 0.1, preferably 0 to 0.03, on an atomic basis.

[0040] Preferably, the catalyst has a porous structure, including micropores, mesopores, and macropores. Micropores may have a pore size of less than 2 nm, for example, 0.4 to 2 nm, mesopores may have a pore size of 2 to 50 nm, and macropores may have a pore size of more than 50 nm, for example, 50 to 500 nm. In one variation, the catalyst has a pore size of 0.03 to 0.15 cm 3 / g, preferably 0.03 to 0.12 cm 3 / g, more preferably 0.05 to 0.10 cm 3 The ratio of the volume of micropores to the total volume of pores is 1 to 7.5%, preferably 1 to 6%, and more preferably 1.7 to 5%.

[0041] Preferably, the catalyst has a fully crystalline structure. As used herein, the term "fully crystalline" means that the molecular sieve catalyst is free or substantially free of amorphous binder. "Substantially free" means that the catalyst contains less than 5% by weight, preferably less than 3% by weight, and more preferably less than 1% by weight of amorphous binder. The binder is converted to MWW molecular sieve, thereby becoming part of the resulting catalyst. The fully crystalline structure can be determined by scanning electron microscopy and X-ray diffraction.

[0042] Preferably, the catalyst has a mechanical strength of 30 to 90 N / cm, preferably 40 to 80 N / cm.

[0043] In a further embodiment, the present disclosure provides a method for preparing a Ti-MWW molecular sieve catalyst, the method comprising the steps of: (1) molding and firing Ti-MWW molecular sieve powder, a binder, a pore-forming agent, and a fluoride to obtain a molded product; (2) crystallizing the formed product of step (1) in the presence of an organic amine solution to obtain a catalyst precursor A; (3) treating the catalyst precursor A from step (2) with an acid solution and calcining it to obtain a catalyst precursor B; (4) A step of treating the catalyst precursor B of the step (3) with an organic amine solution to obtain the catalyst.

[0044] Preferably, the molar ratio of silicon to titanium in the Ti-MWW molecular sieve powder is, on an atomic basis, from 5 to 120. The Ti-MWW molecular sieve powder is commercially available or can be prepared according to techniques disclosed in the art.

[0045] Preferably, the binder is an amorphous binder and includes a silicon source and at least one selected from the group consisting of a boron source and an aluminum source. Preferably, the amorphous binder includes a silicon source and a boron source. More preferably, the silicon source, boron source, and aluminum source are in a molar ratio of 1:x:y, based on oxides, where x = 0 to 0.5, y = 0 to 0.5, and x + y = 0.02 to 1. Preferably, the silicon source is at least one selected from the group consisting of silica sol, sodium silicate, white carbon black, and ethyl orthosilicate; the boron source is at least one selected from the group consisting of boric acid, boron trioxide, and borate salts; and the aluminum source is at least one selected from the group consisting of aluminum oxide, aluminum hydroxide, sodium metaaluminate, aluminum nitrate, and aluminum sulfate. The binder is commercially available or can be prepared according to techniques disclosed in the art. In one variation, the binder is prepared by mixing components (eg, a silicon source, a boron source, and an aluminum source).

[0046] Preferably, the pore-forming agent is at least one selected from the group consisting of sesbania powder, cellulose, chitosan, lignin, starch, polyethylene glycol, poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer (P123) and poly(ethylene oxide)-poly(propylene oxide) copolymer (F127).

[0047] Preferably, the fluoride is at least one selected from the group consisting of sodium fluoride, potassium fluoride, and ammonium fluoride.

[0048] Preferably, in step (1), the Ti-MWW molecular sieve powder, binder, pore-forming agent and fluoride are used in a mass ratio of 1:(0.1-1.5):(0.01-0.1):(0.01-0.4).

[0049] Preferably, in step (1), before molding, the Ti-MWW molecular sieve powder, binder, pore former, and fluoride are kneaded, preferably in the presence of water. Optionally, after kneading and molding in step (1), the product is dried. Preferably, the drying is performed at 60-120°C for 1-24 hours.

[0050] Preferably, in step (1), the firing is carried out in an oxygen-containing atmosphere at 450 to 650° C. for 4 to 12 hours. The oxygen-containing atmosphere may be air or oxygen, and is preferably air.

[0051] Preferably, in step (2), the molded article from step (1) is placed on top of the organic amine solution but is not brought into contact with the organic amine solution.

[0052] Preferably, in step (2), the organic amine is at least one selected from the group consisting of piperidine and hexamethyleneimine. In one variation, the concentration of the organic amine solution is 0.3 to 15 mol / L. Preferably, the extruded product and the organic amine solution are used in a mass ratio of (0.1 to 10):1. In one variation, the crystallization is carried out in a sealed environment at a temperature of 130 to 190°C and autogenous pressure for 1 to 9 days.

[0053] Preferably, step (2) further comprises the step of washing and drying the product after crystallization. Preferably, the washing is with water. Preferably, the drying is carried out at 60 to 120°C for 1 to 24 hours.

[0054] Preferably, step (2) does not include calcination.

[0055] Preferably, step (3) comprises contacting and reacting the catalyst precursor A of step (2) with an acid solution. The acid solution is at least one selected from the group consisting of solutions of nitric acid, hydrochloric acid, sulfuric acid, formic acid, acetic acid, and oxalic acid. The concentration of the acid solution is 0.3 to 12 mol / L. The catalyst precursor A and the acid solution are used in a mass ratio of 1:(10 to 80). The treatment with the acid solution is carried out at a temperature of 60 to 130°C for 4 to 48 hours.

[0056] Optionally, in step (3), after treatment with the acid solution, the product is washed and dried. Preferably, the washing is with water. Preferably, the drying is carried out at 60 to 120°C for 1 to 24 hours.

[0057] Preferably, in step (3), the firing is carried out in an oxygen-containing atmosphere at 450 to 650° C. for 4 to 12 hours. The oxygen-containing atmosphere may be air or oxygen, and is preferably air.

[0058] Preferably, step (4) comprises contacting and reacting the catalyst precursor B of step (3) with an organic amine solution in the presence of a fluoride. The fluoride is at least one selected from the group consisting of sodium fluoride, potassium fluoride, and ammonium fluoride. The organic amine is at least one selected from the group consisting of piperidine and hexamethyleneimine. The concentration of the organic amine solution is 0.3 to 15 mol / L. The catalyst precursor B, fluoride, and organic amine solution are used in a mass ratio of 1:(0.05 to 0.4):(2 to 20). The treatment with the organic amine solution is carried out at a temperature of 130 to 190°C for 4 to 48 hours.

[0059] Optionally, in step (4), after treatment with the organic amine solution, the product is washed and dried. Preferably, the washing is with water. Preferably, the drying is carried out at 60 to 120°C for 1 to 24 hours.

[0060] Preferably, step (4) does not include calcination.

[0061] In a further embodiment, the present disclosure provides a Ti-MWW molecular sieve catalyst prepared by the above method, which has all the characteristics of the Ti-MWW molecular sieve catalyst of the present disclosure, as described above, which will not be repeated here.

[0062] In a further embodiment, provided herein is the use of a Ti-MWW molecular sieve catalyst in the epoxidation of olefins.

[0063] Preferably, the use comprises the steps of mixing an olefin, an aqueous hydrogen peroxide solution, a solvent, and an alkaline nitrogen-containing material to form a feed solution, and contacting and reacting the feed solution and the catalyst. In one variation, the reaction is carried out in a fixed bed reactor.

[0064] Preferably, the olefin is a liquefied olefin. The olefin includes at least one selected from the group consisting of propylene, allyl chloride, butene, pentene, cyclopentene, hexene, and cyclohexene. The concentration of the aqueous hydrogen peroxide solution is 10 to 70 mass %. The solvent is at least one selected from the group consisting of methanol, acetonitrile, propionitrile, acetone, and tert-butyl alcohol. The alkaline nitrogen-containing substance is at least one selected from the group consisting of piperidine and hexamethyleneimine.

[0065] Preferably, the olefin and hydrogen peroxide in the feed solution are in a molar ratio of 1:0.3 to 1. The olefin is present in the feed solution in an amount of 1 to 50 mass %, the solvent is present in the feed solution in an amount of 30 to 90 mass %, and the alkaline nitrogen-containing substance is present in the feed solution in an amount of 1 to 50 ppm.

[0066] Preferably, the reaction is carried out at a catalyst flow rate of 3 to 30 mL g per unit mass of feed solution. cat. -1 h -1The reaction is carried out under conditions of a temperature of 30 to 100°C and a pressure of 0.1 to 4 MPa.

[0067] [Example] The features and advantages of the present invention will become apparent from the following examples, which are intended to illustrate the invention and are not intended to limit the invention in any way.

[0068] [Test method] In the present disclosure, for example, in the following examples and comparative examples, the type, state, structure, and morphology of the titanium species in the molecular sieve catalyst were measured by UV Raman spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and scanning electron microscopy, respectively. The molar ratios of silicon to titanium, boron to silicon, and aluminum to silicon in the molecular sieve catalyst were measured by inductively coupled atomic emission spectroscopy. The micropore volume, mesopore volume, and macropore volume of the molecular sieve catalyst were measured by nitrogen adsorption / desorption and mercury intrusion porosimetry, respectively. Using these results, the ratio of the micropore volume to the total pore volume was calculated as follows: (i.e., ratio of micropore volume to total pore volume) = (micropore volume divided by the sum of the micropore volume, mesopore volume, and macropore volume). The mechanical strength of the molecular sieve catalyst was measured using a strength tester.

[0069] In this disclosure, UV Raman spectroscopy tests were performed using an excitation wavelength of 244 nm, a laser power of 5.0 mW on the sample, and a spectral resolution of 4 cm. -1 The UV Raman spectrum of the molecular sieve catalyst was obtained by subtracting the baseline value from the peak intensity using a Chinese UV Raman-100 UV Raman spectrometer under the following conditions:

[0070] In this disclosure, the X-ray photoelectron spectroscopy test was performed using an AXIS Ultra DLD X-ray photoelectron spectrometer with Al Kα as the light source (1486.6 eV). The sample chamber was 10 -9This included evacuating to a pressure of 0.1 Torr and calibrating with the C 1s peak at 284.8 eV. Peak fitting was performed using OriginPro 9.

[0071] In this disclosure, X-ray diffraction testing involves analyzing samples on a Rigaku UlTima IV powder X-ray diffractometer using a Cu Kα light source (λ = 1.54 Å), a nickel filter, a 2θ scan range of 2–50°, an operating voltage of 40 kV, a current of 40 mA, and a scan rate of 10° / min.

[0072] In this disclosure, scanning electron microscopy includes performing the examination in a Hitachi S-4800 electron microscope at an accelerating voltage of 3 kV.

[0073] In this disclosure, testing by inductively coupled atomic emission spectroscopy involves analyzing samples on a Varian-2000 analyzer to determine the silicon-titanium molar ratio, boron-silicon molar ratio, and aluminum-silicon molar ratio of the samples, which were dissolved in a hydrofluoric acid solution prior to testing.

[0074] In this disclosure, testing by nitrogen adsorption-desorption method involves determining the nitrogen adsorption-desorption isotherm of the sample on an American Micromeritics ASAP2460 instrument, thereby obtaining the micropore volume, which was determined at a temperature of 77 K, and the sample was vacuum pretreated at 573 K for 6 hours before testing.

[0075] In this disclosure, testing by mercury intrusion porosimetry involves conducting the test on a high performance, fully automated mercury intrusion instrument, AutoPore IV 9505.

[0076] In this disclosure, mechanical strength testing involves testing with a DL-2 particle strength tester. Specifically, the size of the catalyst in the direction of the applied force was determined, and then the applied force required to crush the catalyst into powder was determined. The mechanical strength of the catalyst was calculated by dividing the applied force by the size.

[0077] In this disclosure, for example, in the following examples and comparative examples, the catalytic performance of the molecular sieve catalyst is characterized by the percentage of residual hydrogen peroxide, the conversion of hydrogen peroxide, the selectivity to main products (such as epoxides) and to by-products (such as glycols and alcohol ethers), the ratio of main products to by-products, and the stability retention period of the catalyst.

[0078] In this disclosure, a sample of the feed solution was obtained from the inlet of the reaction tube, and a sample of the reaction solution was obtained from the outlet of the reaction tube. The reaction solution sample can be obtained at any stage of the reaction, for example, when the reaction solution has just come out of the outlet of the reaction tube, during the reaction, or at the end of the reaction. The feed solution sample and the reaction solution sample were tested for the concentration of hydrogen peroxide therein by titration with cerium sulfate. The results were used to calculate the percentage of residual hydrogen peroxide and the conversion rate of hydrogen peroxide according to the following formulas: Percentage of residual hydrogen peroxide (%) = Concentration of hydrogen peroxide in reaction solution (mol / L) / Concentration of hydrogen peroxide in feed solution (mol / L) * 100% Conversion rate of hydrogen peroxide (%) = 1 - percentage of residual hydrogen peroxide (%).

[0079] In this disclosure, samples of the feed solution and the reaction solution were analyzed for their composition by gas chromatography, and the results were used to determine the amount of olefin converted during the reaction, the amount of epoxide product produced during the reaction, and thereby calculate the selectivity of the main product (i.e., epoxide) and the ratio of the main product (i.e., epoxide) to the by-products (i.e., glycols and alcohol ethers).

[0080] Molar amount of olefin converted during the reaction = Molar amount of olefin in the feed solution sample - Molar amount of olefin in the reaction solution sample Selectivity to epoxide (%) = moles of epoxide product in a sample of the reaction mixture / moles of olefin converted during the reaction * 100% Ratio of major to minor products = moles of epoxide product in reaction sample / (moles of olefin converted in reaction - moles of epoxide product in reaction sample) * 100%.

[0081] In the present disclosure, the catalyst stability retention period began at the start of the reaction and ended when the percentage of residual hydrogen peroxide in the reaction solution sample reached 2%.

[0082] In the examples and comparative examples, the Ti-MWW molecular sieve powder was RT-03B, commercially available from Zhejiang TWRD New Materials Co., Ltd., and its titanium species contained only framework tetracoordinated titanium species. The as-synthesized Ti-MWW molecular sieve powder was prepared according to the reference (Journal of Physical Chemistry B, 2001, 105, 2897), which contained only extraframework hexacoordinated titanium species.

[0083] Example 1 (1) 90 g of Ti-MWW molecular sieve powder with a silicon-titanium molar ratio of 20, 90 g of amorphous binder (the amorphous binder contained 75 g of silica sol with a mass fraction of 40% silica and 15 g of boric acid), 3 g of sesbania powder, and 9 g of sodium fluoride were mixed under mechanical stirring, and 80 g of water was added. After 4 hours of stirring and kneading, a solid mixture was obtained. This solid mixture was mechanically extruded, dried at 100°C for 8 hours, and calcined at 550°C for 6 hours to obtain a cylindrical molded product.

[0084] (2) 90 g of the cylindrical molding from step (1) was placed on 60 g of a 3 mol / L piperidine solution without contacting it, and crystallized in a sealed environment at 170°C for 2 days. The product was washed with water and dried at 100°C for 8 hours to obtain a cylindrical catalyst precursor A.

[0085] (3) 60 g of the cylindrical catalyst precursor A from step (2) and a 2 mol / L nitric acid solution were mixed in a mass ratio of 1:50, reacted at 80°C for 24 hours, washed with water, dried at 100°C for 8 hours, and calcined at 550°C for 6 hours to obtain a cylindrical catalyst precursor B.

[0086] (4) 40 g of the cylindrical catalyst precursor B from step (3), ammonium fluoride, and 3 mol / L piperidine solution were mixed in a mass ratio of 1:0.1:10 and reacted at 170°C for 24 hours. The mixture was washed with water and dried at 100°C for 8 hours to obtain the Ti-MWW molecular sieve catalyst, which was recorded as S1.

[0087] Catalyst S1 was tested as above.

[0088] The X-ray photoelectron spectrum of catalyst S1 is shown in Figure 1. The spectrum showed peaks at 458.9, 460.3, 464.8, and 465.9 eV, among which the peaks at 460.3 and 465.9 eV were assigned to framework tetracoordinated titanium species, and the peaks at 458.9 and 464.8 eV were assigned to modified extraframework hexacoordinated titanium species.

[0089] The UV Raman spectrum of catalyst S1 is shown in Figure 2, with peaks at 343, 484, 699 and 1097 cm -1 A peak was observed at 699 cm -1 The intensity of the peak at 343 cm -1 is 5.3 times the intensity of the peak at 1097 cm -1 The intensity of the peak at 343 cm -1 The intensity of the peak at 343 cm was 5.1 times that of the peak at 343 cm. -1 The peak at 484 cm is assigned to the MWW structure. -1 and 1097 cm -1 The peak at 699 cm is assigned to framework tetracoordinate titanium species. -1 The peak in was assigned to the modified extraframework hexacoordinated titanium species.

[0090] The X-ray diffraction pattern of catalyst S1 is shown in Figure 3. There were strong diffraction peaks at 2θ of 3.3°, 6.6°, 7.2°, 7.9°, 9.7°, and 26.1°, and the intensity of the diffraction peak at 2θ of 7.2° reached 5300, indicating that S1 had an MWW structure and high crystallinity.

[0091] A scanning electron microscope image of catalyst S1 is shown in Figure 4. Catalyst S1 exhibited a lamellar morphology, and no nanoparticles were observed, indicating that S1 had only an MWW structure.

[0092] Catalyst S1 had a silicon-titanium molar ratio of 35 and a boron-silicon molar ratio of 0.015.

[0093] Catalyst S1 has a micropore volume of 0.09 cm 3 / g, the ratio of the micropore volume to the total pore volume was 3.6%, and the mechanical strength was 66 N / cm.

[0094] Example 2 (1) 90 g of Ti-MWW molecular sieve powder with a silicon-titanium molar ratio of 5, 90 g of amorphous binder (the amorphous binder contained 75 g of silica sol with a mass fraction of 40% silica and 15 g of boric acid), 3 g of starch, and 0.9 g of potassium fluoride were mixed under mechanical stirring, and 80 g of water was added thereto. After 4 hours of stirring and kneading, a solid mixture was obtained. This solid mixture was subjected to mechanical extrusion molding, dried at 100°C for 8 hours, and calcined at 550°C for 6 hours to obtain a cylindrical molding.

[0095] (2) 90 g of the cylindrical molding from step (1) was placed on 60 g of a 3 mol / L piperidine solution without contacting it, and crystallized in a sealed environment at 170°C for 2 days. The product was washed with water and dried at 100°C for 8 hours to obtain a cylindrical catalyst precursor A.

[0096] (3) 60 g of the cylindrical catalyst precursor A from step (2) and a 2 mol / L nitric acid solution were mixed in a solid-liquid ratio of 1:50 by mass, reacted at 80°C for 24 hours, washed with water, dried at 100°C for 8 hours, and calcined at 550°C for 6 hours to obtain a cylindrical catalyst precursor B.

[0097] (4) 40 g of the cylindrical catalyst precursor B from step (3), ammonium fluoride, and 3 mol / L piperidine solution were mixed in a mass ratio of 1:0.1:10 and reacted at 170°C for 24 hours. The mixture was washed with water and dried at 100°C for 8 hours to obtain the Ti-MWW molecular sieve catalyst, which was recorded as S2.

[0098] Catalyst S2 was tested as above.

[0099] The X-ray photoelectron spectrum of catalyst S2 showed peaks at 459.1, 460.1, 465.0, and 465.7 eV.

[0100] The UV Raman spectrum of catalyst S2 shows peaks at 341, 487, 702 and 1094 cm -1 A peak was observed at 702 cm -1 The intensity of the peak at 341 cm -1 is 10 times the intensity of the peak at 1094 cm -1 The intensity of the peak at 341 cm -1 The intensity of the peak was 10 times that of the peak at

[0101] The X-ray diffraction pattern and scanning electron microscope image of catalyst S2 were similar to those shown in Figures 3 and 4, respectively.

[0102] Catalyst S2 had a silicon-titanium molar ratio of 10 and a boron-silicon molar ratio of 0.005.

[0103] Catalyst S2 has a micropore volume of 0.05 cm 3 / g, the ratio of the micropore volume to the total pore volume was 1.7%, and the mechanical strength was 40 N / cm.

[0104] Example 3 (1) 90 g of Ti-MWW molecular sieve powder with a silicon-to-titanium molar ratio of 120, 90 g of amorphous binder (the amorphous binder contained 75 g of silica sol with a mass fraction of 40% silica and 15 g of boric acid), 9 g of cellulose, and 36 g of ammonium fluoride were mixed under mechanical stirring, and 80 g of water was added. After 4 hours of stirring and kneading, a solid mixture was obtained. This solid mixture was mechanically extruded, dried at 100°C for 8 hours, and calcined at 550°C for 6 hours to obtain a cylindrical molded product.

[0105] (2) 90 g of the cylindrical molding from step (1) was placed on 60 g of a 3 mol / L piperidine solution without contacting it, and crystallized in a sealed environment at 170°C for 2 days. The product was washed with water and dried at 100°C for 8 hours to obtain a cylindrical catalyst precursor A.

[0106] (3) 60 g of the cylindrical catalyst precursor A from step (2) and a 2 mol / L nitric acid solution were mixed in a mass ratio of 1:50, reacted at 80°C for 24 hours, washed with water, dried at 100°C for 8 hours, and calcined at 550°C for 6 hours to obtain a cylindrical catalyst precursor B.

[0107] (4) 40 g of the cylindrical catalyst precursor B from step (3), ammonium fluoride, and 3 mol / L piperidine solution were mixed in a mass ratio of 1:0.1:10 and reacted at 170°C for 24 hours. The mixture was washed with water and dried at 100°C for 8 hours to obtain the Ti-MWW molecular sieve catalyst, which was recorded as S3.

[0108] Catalyst S3 was tested as above.

[0109] The X-ray photoelectron spectrum of catalyst S3 showed peaks at 458.7, 460.4, 464.6, and 466.0 eV.

[0110] The UV Raman spectrum of catalyst S3 shows peaks at 345, 482, 696 and 1099 cm -1 It showed a peak at 696 cm -1 The intensity of the peak at 345 cm -1 is 0.5 times the intensity of the peak at 1099 cm-1 The intensity of the peak at 345 cm -1 The intensity of the peak was 0.5 times that of the peak at

[0111] The X-ray diffraction pattern and scanning electron microscope image of catalyst S3 were similar to those shown in Figures 3 and 4, respectively.

[0112] Catalyst S3 had a silicon-titanium molar ratio of 200 and a boron-silicon molar ratio of 0.03.

[0113] Catalyst S3 has a micropore volume of 0.07 cm 3 / g, the ratio of the micropore volume to the total pore volume was 2.3%, and the mechanical strength was 80 N / cm.

[0114] Example 4 (1) 90 g of Ti-MWW molecular sieve powder with a silicon-titanium molar ratio of 20, 9 g of amorphous binder (the amorphous binder contained 8 g of silica sol with a mass fraction of 25% silica and 1 g of sodium tetraborate), 3 g of sesbania powder, and 9 g of sodium fluoride were mixed under mechanical stirring, and 120 g of water was added. After 4 hours of stirring and kneading, a solid mixture was obtained. This solid mixture was mechanically extruded, dried at 100°C for 8 hours, and calcined at 450°C for 12 hours to obtain a cylindrical molded product.

[0115] (2) 90 g of the cylindrical molding from step (1) was placed on 60 g of a 3 mol / L piperidine solution without contacting it, and crystallized in a sealed environment at 170°C for 2 days. The product was washed with water and dried at 100°C for 8 hours to obtain a cylindrical catalyst precursor A.

[0116] (3) 60 g of the cylindrical catalyst precursor A from step (2) and a 2 mol / L nitric acid solution were mixed in a mass ratio of 1:50, reacted at 80°C for 24 hours, washed with water, dried at 100°C for 8 hours, and calcined at 550°C for 6 hours to obtain a cylindrical catalyst precursor B.

[0117] (4) 40 g of the cylindrical catalyst precursor B from step (3), ammonium fluoride, and 3 mol / L piperidine solution were mixed in a mass ratio of 1:0.1:10 and reacted at 170°C for 24 hours. The mixture was washed with water and dried at 100°C for 8 hours to obtain the Ti-MWW molecular sieve catalyst, which was recorded as S4.

[0118] Catalyst S4 was tested as above.

[0119] The X-ray photoelectron spectrum of catalyst S4 showed peaks at 458.7, 460.5, 464.6, and 466.1 eV.

[0120] The UV Raman spectrum of catalyst S4 shows peaks at 347, 480, 695 and 1101 cm -1 A peak was observed at 695 cm -1 The intensity of the peak at 347 cm -1 is 8.2 times the intensity of the peak at 1101 cm -1 The intensity of the peak at 347 cm -1 The intensity of the peak was 7.8 times that of the peak at

[0121] The X-ray diffraction pattern and scanning electron microscope image of catalyst S4 were similar to those shown in Figures 3 and 4, respectively.

[0122] Catalyst S4 had a silicon-titanium molar ratio of 25 and a boron-silicon molar ratio of 0.003.

[0123] Catalyst S4 has a micropore volume of 0.06 cm 3 / g, the ratio of the micropore volume to the total pore volume was 2%, and the mechanical strength was 30 N / cm.

[0124] Example 5 (1) 90 g of Ti-MWW molecular sieve powder with a silicon-titanium molar ratio of 20, 90 g of amorphous binder (the amorphous binder contained 30 g of white carbon black, 30 g of boric acid, and 30 g of aluminum hydroxide), 3 g of sesbania powder, and 9 g of sodium fluoride were mixed under mechanical stirring, and 120 g of water was added thereto. After 4 hours of stirring and kneading, a solid mixture was obtained. This solid mixture was subjected to mechanical extrusion molding, dried at 100°C for 8 hours, and calcined at 650°C for 4 hours to obtain a cylindrical molding.

[0125] (2) 90 g of the cylindrical molding from step (1) was placed on 60 g of a 3 mol / L piperidine solution without contacting it, and crystallized in a sealed environment at 170°C for 2 days. The product was washed with water and dried at 100°C for 8 hours to obtain a cylindrical catalyst precursor A.

[0126] (3) 60 g of the cylindrical catalyst precursor A from step (2) and a 2 mol / L nitric acid solution were mixed in a mass ratio of 1:50, reacted at 80°C for 24 hours, washed with water, dried at 100°C for 8 hours, and calcined at 550°C for 6 hours to obtain a cylindrical catalyst precursor B.

[0127] (4) 40 g of the cylindrical catalyst precursor B from step (3), ammonium fluoride, and 3 mol / L piperidine solution were mixed in a mass ratio of 1:0.1:10 and reacted at 170°C for 24 hours. The mixture was washed with water and dried at 100°C for 8 hours to obtain the Ti-MWW molecular sieve catalyst, which was recorded as S5.

[0128] Catalyst S5 was tested as above.

[0129] The X-ray photoelectron spectrum of catalyst S5 showed peaks at 459.0, 460.2, 464.9, and 465.8 eV.

[0130] The UV Raman spectrum of catalyst S5 shows peaks at 341, 486, 701 and 1095 cm -1 It showed a peak at 701 cm -1 The intensity of the peak at 341 cm -1is 2.9 times the intensity of the peak at 1095 cm -1 The intensity of the peak at 341 cm -1 The intensity of the peak was 2.6 times that of the peak at

[0131] The X-ray diffraction pattern and scanning electron microscope image of catalyst S5 were similar to those shown in Figures 3 and 4, respectively.

[0132] Catalyst S5 had a silicon-titanium molar ratio of 60, a boron-silicon molar ratio of 0.1, and an aluminum-silicon molar ratio of 0.1.

[0133] Catalyst S5 has a micropore volume of 0.1 cm 3 / g, the ratio of the micropore volume to the total pore volume was 4%, and the mechanical strength was 77 N / cm.

[0134] Example 6 (1) 90 g of Ti-MWW molecular sieve powder with a silicon-titanium molar ratio of 20, 90 g of amorphous binder (the amorphous binder contained 75 g of silica sol with a mass fraction of 40% silica and 15 g of aluminum hydroxide), 3 g of sesbania powder, and 9 g of sodium fluoride were mixed under mechanical stirring, and 80 g of water was added. After 4 hours of stirring and kneading, a solid mixture was obtained. This solid mixture was mechanically extruded, dried at 100°C for 8 hours, and calcined at 550°C for 6 hours to obtain a cylindrical molded product.

[0135] (2) 90 g of the cylindrical molding from step (1) was placed on 60 g of a 3 mol / L piperidine solution without contacting it, and crystallized in a sealed environment at 170°C for 2 days. The product was washed with water and dried at 100°C for 8 hours to obtain a cylindrical catalyst precursor A.

[0136] (3) 60 g of the cylindrical catalyst precursor A from step (2) and a 2 mol / L nitric acid solution were mixed in a mass ratio of 1:50, reacted at 80°C for 24 hours, washed with water, dried at 100°C for 8 hours, and calcined at 550°C for 6 hours to obtain a cylindrical catalyst precursor B.

[0137] (4) 40 g of the cylindrical catalyst precursor B from step (3), ammonium fluoride, and 3 mol / L piperidine solution were mixed in a mass ratio of 1:0.1:10 and reacted at 170°C for 24 hours. The mixture was washed with water and dried at 100°C for 8 hours to obtain the Ti-MWW molecular sieve catalyst, which was recorded as S6.

[0138] Catalyst S6 was tested as above.

[0139] The X-ray photoelectron spectrum of catalyst S6 showed peaks at 459.1, 460.1, 465.0, and 465.7 eV.

[0140] The UV Raman spectrum of catalyst S6 shows peaks at 339, 488, 703 and 1093 cm -1 A peak was observed at 703 cm -1 The intensity of the peak at 339 cm -1 is 4.9 times the intensity of the peak at 1093 cm -1 The intensity of the peak at 339 cm -1 The intensity of the peak was 5.2 times that of the peak at

[0141] The X-ray diffraction pattern and scanning electron microscope image of catalyst S6 were similar to those shown in Figures 3 and 4, respectively.

[0142] Catalyst S6 had a silicon-titanium molar ratio of 37 and an aluminum-silicon molar ratio of 0.05.

[0143] Catalyst S6 has a micropore volume of 0.12 cm 3 / g, the ratio of the micropore volume to the total pore volume was 6%, and the mechanical strength was 90 N / cm.

[0144] Example 7 (1) 90 g of Ti-MWW molecular sieve powder with a silicon-titanium molar ratio of 20, 90 g of amorphous binder (the amorphous binder contained 75 g of silica sol with a mass fraction of 40% silica and 15 g of boric acid), 3 g of sesbania powder, and 9 g of sodium fluoride were mixed under mechanical stirring, and 80 g of water was added thereto. After 4 hours of stirring and kneading, a solid mixture was obtained. This solid mixture was spheronized, dried at 100°C for 8 hours, and calcined at 550°C for 6 hours to obtain spherical molded products.

[0145] (2) 90 g of the spherical molded product from step (1) was placed on 60 g of a 3 mol / L piperidine solution without contacting it, and crystallized in a sealed environment at 170°C for 2 days. The product was washed with water and dried at 100°C for 8 hours to obtain a spherical catalyst precursor A.

[0146] (3) 60 g of the spherical catalyst precursor A from step (2) and a 2 mol / L nitric acid solution were mixed in a mass ratio of 1:50, reacted at 80°C for 24 hours, washed with water, dried at 100°C for 8 hours, and calcined at 550°C for 6 hours to obtain a spherical catalyst precursor B.

[0147] (4) 40 g of the spherical catalyst precursor B from step (3), ammonium fluoride, and 3 mol / L piperidine solution were mixed in a mass ratio of 1:0.1:10 and reacted at 170°C for 24 hours. The mixture was washed with water and dried at 100°C for 8 hours to obtain a Ti-MWW molecular sieve catalyst, which was recorded as S7.

[0148] Catalyst S7 was tested as above.

[0149] The X-ray photoelectron spectrum of catalyst S7 showed peaks at 458.9, 460.3, 464.8, and 465.9 eV.

[0150] The UV Raman spectrum of catalyst S7 shows peaks at 343, 484, 699 and 1097 cm -1 A peak was observed at 699 cm -1 The intensity of the peak at 343 cm -1 is 5.3 times the intensity of the peak at 1097 cm-1 The intensity of the peak at 343 cm -1 The intensity of the peak was 5.2 times that of the peak at

[0151] The X-ray diffraction pattern and scanning electron microscope image of catalyst S7 were similar to those shown in Figures 3 and 4, respectively.

[0152] Catalyst S7 had a silicon-titanium molar ratio of 34 and a boron-silicon molar ratio of 0.014.

[0153] Catalyst S7 has a micropore volume of 0.09 cm 3 / g, the ratio of the micropore volume to the total pore volume was 3.6%, and the mechanical strength was 80 N / cm.

[0154] Example 8 (1) 90 g of Ti-MWW molecular sieve powder with a silicon-titanium molar ratio of 20, 90 g of amorphous binder (the amorphous binder contained 75 g of silica sol with a mass fraction of 40% silica and 15 g of boric acid), 3 g of sesbania powder, and 9 g of sodium fluoride were mixed under mechanical stirring, and 80 g of water was added. After 4 hours of stirring and kneading, a solid mixture was obtained. This solid mixture was mechanically extruded, dried at 100°C for 8 hours, and calcined at 550°C for 6 hours to obtain a cylindrical molded product.

[0155] (2) 90 g of the cylindrical molding from step (1) was placed on 900 g of 0.3 mol / L piperidine solution without contacting it, and crystallized in a sealed environment at 170°C for 2 days. The product was washed with water and dried at 100°C for 8 hours to obtain a cylindrical catalyst precursor A.

[0156] (3) 60 g of the cylindrical catalyst precursor A from step (2) and a 2 mol / L nitric acid solution were mixed in a mass ratio of 1:50, reacted at 80°C for 24 hours, washed with water, dried at 100°C for 8 hours, and calcined at 550°C for 6 hours to obtain a cylindrical catalyst precursor B.

[0157] (4) 40 g of the cylindrical catalyst precursor B from step (3), ammonium fluoride, and 3 mol / L piperidine solution were mixed in a mass ratio of 1:0.1:10 and reacted at 170°C for 24 hours. The mixture was washed with water and dried at 100°C for 8 hours to obtain the Ti-MWW molecular sieve catalyst, which was recorded as S8.

[0158] Catalyst S8 was tested as above.

[0159] The X-ray photoelectron spectrum of catalyst S8 showed peaks at 459.0, 460.2, 464.9, and 465.8 eV.

[0160] The UV Raman spectrum of catalyst S8 shows peaks at 341, 486, 701 and 1095 cm -1 A peak was observed at 701 cm -1 The intensity of the peak at 341 cm -1 is 4.8 times the intensity of the peak at 1095 cm -1 The intensity of the peak at 341 cm -1 The intensity of the peak was 5.9 times that of the peak at

[0161] The X-ray diffraction pattern and scanning electron microscope image of catalyst S8 were similar to those shown in Figures 3 and 4, respectively.

[0162] Catalyst S8 had a silicon-titanium molar ratio of 32 and a boron-silicon molar ratio of 0.017.

[0163] Catalyst S8 has a micropore volume of 0.07 cm 3 / g, the ratio of the micropore volume to the total pore volume was 2.3%, and the mechanical strength was 56 N / cm.

[0164] Example 9 (1) 90 g of Ti-MWW molecular sieve powder with a silicon-titanium molar ratio of 20, 90 g of amorphous binder (the amorphous binder contained 75 g of silica sol with a mass fraction of 40% silica and 15 g of boric acid), 3 g of sesbania powder, and 9 g of sodium fluoride were mixed under mechanical stirring, and 80 g of water was added. After 4 hours of stirring and kneading, a solid mixture was obtained. This solid mixture was mechanically extruded, dried at 100°C for 8 hours, and calcined at 550°C for 6 hours to obtain a cylindrical molded product.

[0165] (2) 90 g of the cylindrical molding from step (1) was placed on 9 g of a 15 mol / L piperidine solution without contacting it, and crystallized in a sealed environment at 170°C for 2 days. The product was washed with water and dried at 100°C for 8 hours to obtain a cylindrical catalyst precursor A.

[0166] (3) 60 g of the cylindrical catalyst precursor A from step (2) and a 2 mol / L nitric acid solution were mixed in a mass ratio of 1:50, reacted at 80°C for 24 hours, washed with water, dried at 100°C for 8 hours, and calcined at 550°C for 6 hours to obtain a cylindrical catalyst precursor B.

[0167] (4) 40 g of the cylindrical catalyst precursor B from step (3), ammonium fluoride, and 3 mol / L piperidine solution were mixed in a mass ratio of 1:0.1:10 and reacted at 170°C for 24 hours. The mixture was washed with water and dried at 100°C for 8 hours to obtain the Ti-MWW molecular sieve catalyst, which was recorded as S9.

[0168] Catalyst S9 was tested as above.

[0169] The X-ray photoelectron spectrum of catalyst S9 showed peaks at 458.9, 460.4, 464.8, and 466.0 eV.

[0170] The UV Raman spectrum of catalyst S9 shows peaks at 345, 483, 698 and 1099 cm -1 It showed a peak at 698 cm -1 The intensity of the peak at 345 cm -1 is 5.7 times the intensity of the peak at 1099 cm-1 The intensity of the peak at 345 cm -1 The intensity of the peak was 4.9 times that of the peak at

[0171] The X-ray diffraction pattern and scanning electron microscope image of catalyst S9 were similar to those shown in Figures 3 and 4, respectively.

[0172] Catalyst S9 had a silicon-titanium molar ratio of 34 and a boron-silicon molar ratio of 0.016.

[0173] Catalyst S9 has a micropore volume of 0.08 cm 3 / g, the ratio of the micropore volume to the total pore volume was 3.2%, and the mechanical strength was 64 N / cm.

[0174] Example 10 (1) 90 g of Ti-MWW molecular sieve powder with a silicon-titanium molar ratio of 20, 90 g of amorphous binder (the amorphous binder contained 75 g of silica sol with a mass fraction of 40% silica and 15 g of boric acid), 3 g of sesbania powder, and 9 g of sodium fluoride were mixed under mechanical stirring, and 80 g of water was added. After 4 hours of stirring and kneading, a solid mixture was obtained. This solid mixture was mechanically extruded, dried at 100°C for 8 hours, and calcined at 550°C for 6 hours to obtain a cylindrical molded product.

[0175] (2) 90 g of the cylindrical molding from step (1) was placed on 60 g of a 3 mol / L hexamethyleneimine solution without contacting it, and crystallized in a sealed environment at 130°C for 9 days. The product was washed with water and dried at 100°C for 8 hours to obtain a cylindrical catalyst precursor A.

[0176] (3) 60 g of the cylindrical catalyst precursor A from step (2) and a 2 mol / L nitric acid solution were mixed in a mass ratio of 1:50, reacted at 80°C for 24 hours, washed with water, dried at 100°C for 8 hours, and calcined at 550°C for 6 hours to obtain a cylindrical catalyst precursor B.

[0177] (4) 40 g of the cylindrical catalyst precursor B from step (3), ammonium fluoride, and 3 mol / L piperidine solution were mixed in a mass ratio of 1:0.1:10 and reacted at 170°C for 24 hours. The mixture was washed with water and dried at 100°C for 8 hours to obtain the Ti-MWW molecular sieve catalyst, which was recorded as S10.

[0178] Catalyst S10 was tested as above.

[0179] The X-ray photoelectron spectrum of catalyst S10 showed peaks at 459.0, 460.2, 464.9, and 465.8 eV.

[0180] The UV Raman spectrum of catalyst S10 shows peaks at 341, 486, 701 and 1095 cm -1 It showed a peak at 701 cm -1 The intensity of the peak at 341 cm -1 is 4.5 times the intensity of the peak at 1095 cm -1 The intensity of the peak at 341 cm -1 The intensity of the peak was 4.9 times that of the peak at

[0181] The X-ray diffraction pattern and scanning electron microscope image of catalyst S10 were similar to those shown in Figures 3 and 4, respectively.

[0182] Catalyst S10 had a silicon-titanium molar ratio of 42 and a boron-silicon molar ratio of 0.02.

[0183] Catalyst S10 has a micropore volume of 0.06 cm 3 / g, the ratio of the micropore volume to the total pore volume was 2%, and the mechanical strength was 45 N / cm.

[0184] Example 11 (1) 90 g of Ti-MWW molecular sieve powder with a silicon-titanium molar ratio of 20, 90 g of amorphous binder (the amorphous binder contained 75 g of silica sol with a mass fraction of 40% silica and 15 g of boric acid), 3 g of sesbania powder, and 9 g of sodium fluoride were mixed under mechanical stirring, and 80 g of water was added. After 4 hours of stirring and kneading, a solid mixture was obtained. This solid mixture was mechanically extruded, dried at 100°C for 8 hours, and calcined at 550°C for 6 hours to obtain a cylindrical molded product.

[0185] (2) 90 g of the cylindrical molding from step (1) was placed on 60 g of a 3 mol / L hexamethyleneimine solution without contacting it, and crystallized in a sealed environment at 190°C for 1 day. The product was washed with water and dried at 100°C for 8 hours to obtain a cylindrical catalyst precursor A.

[0186] (3) 60 g of the cylindrical catalyst precursor A from step (2) and a 2 mol / L nitric acid solution were mixed in a mass ratio of 1:50, reacted at 80°C for 24 hours, washed with water, dried at 100°C for 8 hours, and calcined at 550°C for 6 hours to obtain a cylindrical catalyst precursor B.

[0187] (4) 40 g of the cylindrical catalyst precursor B from step (3), ammonium fluoride, and 3 mol / L piperidine solution were mixed in a mass ratio of 1:0.1:10 and reacted at 170°C for 24 hours. The mixture was washed with water and dried at 100°C for 8 hours to obtain the Ti-MWW molecular sieve catalyst, which was recorded as S11.

[0188] Catalyst S11 was tested as described above.

[0189] The X-ray photoelectron spectrum of catalyst S11 showed peaks at 458.9, 460.4, 464.8, and 466.0 eV.

[0190] The UV Raman spectrum of catalyst S11 shows peaks at 345, 482, 698 and 1099 cm -1 It showed a peak at 698 cm -1 The intensity of the peak at 345 cm -1is six times the intensity of the peak at 1099 cm -1 The intensity of the peak at 345 cm -1 The intensity of the peak was five times that of the peak at

[0191] The X-ray diffraction pattern and scanning electron microscope image of catalyst S11 were similar to those shown in Figures 3 and 4, respectively.

[0192] Catalyst S11 had a silicon-titanium molar ratio of 30 and a boron-silicon molar ratio of 0.01.

[0193] Catalyst S11 has a micropore volume of 0.07 cm 3 / g, the ratio of the micropore volume to the total pore volume was 2.3%, and the mechanical strength was 69 N / cm.

[0194] Example 12 (1) 90 g of Ti-MWW molecular sieve powder with a silicon-titanium molar ratio of 20, 90 g of amorphous binder (the amorphous binder contained 75 g of silica sol with a mass fraction of 40% silica and 15 g of boric acid), 3 g of sesbania powder, and 9 g of sodium fluoride were mixed under mechanical stirring, and 80 g of water was added. After 4 hours of stirring and kneading, a solid mixture was obtained. This solid mixture was mechanically extruded, dried at 100°C for 8 hours, and calcined at 550°C for 6 hours to obtain a cylindrical molded product.

[0195] (2) 90 g of the cylindrical molding from step (1) was placed on 60 g of a 3 mol / L piperidine solution without contacting it, and crystallized in a sealed environment at 170°C for 2 days. The product was washed with water and dried at 100°C for 8 hours to obtain a cylindrical catalyst precursor A.

[0196] (3) 60 g of the cylindrical catalyst precursor A from step (2) and a 12 mol / L hydrochloric acid solution were mixed in a mass ratio of 1:10, reacted at 130°C for 4 hours, washed with water, dried at 100°C for 8 hours, and calcined at 450°C for 12 hours to obtain a cylindrical catalyst precursor B.

[0197] (4) 40 g of the cylindrical catalyst precursor B from step (3), ammonium fluoride, and 3 mol / L piperidine solution were mixed in a mass ratio of 1:0.1:10 and reacted at 170°C for 24 hours. The mixture was washed with water and dried at 100°C for 8 hours to obtain the Ti-MWW molecular sieve catalyst, which was recorded as S12.

[0198] Catalyst S12 was tested as above.

[0199] The X-ray photoelectron spectrum of catalyst S12 showed peaks at 458.9, 460.5, 464.8, and 466.1 eV.

[0200] The UV Raman spectrum of catalyst S12 shows peaks at 344, 481, 698 and 1100 cm -1 It showed a peak at 698 cm -1 The intensity of the peak at 344 cm -1 is 3.3 times the intensity of the peak at 1100 cm -1 The intensity of the peak at 344 cm -1 The intensity of the peak was 2.4 times that of the peak at

[0201] The X-ray diffraction pattern and scanning electron microscope image of catalyst S12 were similar to those shown in Figures 3 and 4, respectively.

[0202] Catalyst S12 had a silicon-titanium molar ratio of 57 and a boron-silicon molar ratio of 0.004.

[0203] Catalyst S12 has a micropore volume of 0.1 cm 3 / g, the ratio of the micropore volume to the total pore volume was 4%, and the mechanical strength was 48 N / cm.

[0204] Example 13 (1) 90 g of Ti-MWW molecular sieve powder with a silicon-titanium molar ratio of 20, 90 g of amorphous binder (the amorphous binder contained 75 g of silica sol with a mass fraction of 40% silica and 15 g of boric acid), 3 g of sesbania powder, and 9 g of sodium fluoride were mixed under mechanical stirring, and 80 g of water was added. After 4 hours of stirring and kneading, a solid mixture was obtained. This solid mixture was mechanically extruded, dried at 100°C for 8 hours, and calcined at 550°C for 6 hours to obtain a cylindrical molded product.

[0205] (2) 90 g of the cylindrical molding from step (1) was placed on 60 g of a 3 mol / L piperidine solution without contacting it, and crystallized in a sealed environment at 170°C for 2 days. The product was washed with water and dried at 100°C for 8 hours to obtain a cylindrical catalyst precursor A.

[0206] (3) 60 g of the cylindrical catalyst precursor A from step (2) and a 0.3 mol / L oxalic acid solution were mixed in a mass ratio of 1:80, reacted at 60°C for 48 hours, washed with water, dried at 100°C for 8 hours, and calcined at 650°C for 4 hours to obtain a cylindrical catalyst precursor B.

[0207] (4) 40 g of the cylindrical catalyst precursor B from step (3), ammonium fluoride, and 3 mol / L piperidine solution were mixed in a mass ratio of 1:0.1:10 and reacted at 170°C for 24 hours. The mixture was washed with water and dried at 100°C for 8 hours to obtain the Ti-MWW molecular sieve catalyst, which was recorded as S13.

[0208] Catalyst S13 was tested as above.

[0209] The X-ray photoelectron spectrum of catalyst S13 showed peaks at 459.1, 460.1, 465.0, and 465.7 eV.

[0210] The UV Raman spectrum of catalyst S13 shows peaks at 341, 488, 702 and 1093 cm -1 A peak was observed at 702 cm -1 The intensity of the peak at 341 cm -1is 5.9 times the intensity of the peak at 1093 cm -1 The intensity of the peak at 341 cm -1 The intensity of the peak was 5.7 times that of the peak at

[0211] The X-ray diffraction pattern and scanning electron microscope image of catalyst S13 were similar to those shown in Figures 3 and 4, respectively.

[0212] Catalyst S13 had a silicon-titanium molar ratio of 27 and a boron-silicon molar ratio of 0.08.

[0213] Catalyst S13 has a micropore volume of 0.05 cm 3 / g, the ratio of the micropore volume to the total pore volume was 1.7%, and the mechanical strength was 60 N / cm.

[0214] Example 14 (1) 90 g of Ti-MWW molecular sieve powder with a silicon-titanium molar ratio of 20, 90 g of amorphous binder (the amorphous binder contained 75 g of silica sol with a mass fraction of 40% silica and 15 g of boric acid), 3 g of sesbania powder, and 9 g of sodium fluoride were mixed under mechanical stirring, and 80 g of water was added. After 4 hours of stirring and kneading, a solid mixture was obtained. This solid mixture was mechanically extruded, dried at 100°C for 8 hours, and calcined at 550°C for 6 hours to obtain a cylindrical molded product.

[0215] (2) 90 g of the cylindrical molding from step (1) was placed on 60 g of a 3 mol / L piperidine solution without contacting it, and crystallized in a sealed environment at 170°C for 2 days. The product was washed with water and dried at 100°C for 8 hours to obtain a cylindrical catalyst precursor A.

[0216] (3) 60 g of the cylindrical catalyst precursor A from step (2) and a 2 mol / L nitric acid solution were mixed in a mass ratio of 1:50, reacted at 80°C for 24 hours, washed with water, dried at 100°C for 8 hours, and calcined at 550°C for 6 hours to obtain a cylindrical catalyst precursor B.

[0217] (4) 40 g of the cylindrical catalyst precursor B from step (3), ammonium fluoride, and 3 mol / L hexamethyleneimine solution were mixed in a mass ratio of 1:0.2:20 and reacted at 170°C for 48 hours. The mixture was washed with water and dried at 100°C for 8 hours to obtain a Ti-MWW molecular sieve catalyst, which was recorded as S14.

[0218] Catalyst S14 was tested as above.

[0219] The X-ray photoelectron spectrum of catalyst S14 showed peaks at 458.9, 460.3, 464.8, and 465.9 eV.

[0220] The UV Raman spectrum of catalyst S14 shows peaks at 342, 484, 700 and 1097 cm -1 A peak was observed at 700 cm -1 The intensity of the peak at 342 cm -1 is five times the intensity of the peak at 1097 cm -1 The intensity of the peak at 342 cm -1 The intensity of the peak was 4.8 times that of the peak at

[0221] The X-ray diffraction pattern and scanning electron microscope image of catalyst S14 were similar to those shown in Figures 3 and 4, respectively.

[0222] Catalyst S14 had a silicon-titanium molar ratio of 39 and a boron-silicon molar ratio of 0.018.

[0223] Catalyst S14 has a micropore volume of 0.08 cm 3 / g, the ratio of the micropore volume to the total pore volume was 3.2%, and the mechanical strength was 62 N / cm.

[0224] Example 15 (1) 90 g of Ti-MWW molecular sieve powder with a silicon-titanium molar ratio of 20, 90 g of amorphous binder (the amorphous binder contained 75 g of silica sol with a mass fraction of 40% silica and 15 g of boric acid), 3 g of sesbania powder, and 9 g of sodium fluoride were mixed under mechanical stirring, and 80 g of water was added. After 4 hours of stirring and kneading, a solid mixture was obtained. This solid mixture was mechanically extruded, dried at 100°C for 8 hours, and calcined at 550°C for 6 hours to obtain a cylindrical molded product.

[0225] (2) 90 g of the cylindrical molding from step (1) was placed on 60 g of a 3 mol / L piperidine solution without contacting it, and crystallized in a sealed environment at 170°C for 2 days. The product was washed with water and dried at 100°C for 8 hours to obtain a cylindrical catalyst precursor A.

[0226] (3) 60 g of the cylindrical catalyst precursor A from step (2) and a 2 mol / L nitric acid solution were mixed in a mass ratio of 1:50, reacted at 80°C for 24 hours, washed with water, dried at 100°C for 8 hours, and calcined at 550°C for 6 hours to obtain a cylindrical catalyst precursor B.

[0227] (4) 40 g of the cylindrical catalyst precursor B from step (3), potassium fluoride, and 15 mol / L piperidine solution were mixed in a mass ratio of 1:0.4:2 and reacted at 190°C for 4 hours. The mixture was washed with water and dried at 100°C for 8 hours to obtain a Ti-MWW molecular sieve catalyst, which was recorded as S15.

[0228] Catalyst S15 was tested as above.

[0229] The X-ray photoelectron spectrum of catalyst S15 showed peaks at 459.0, 460.2, 464.9, and 465.8 eV.

[0230] The UV Raman spectrum of catalyst S15 shows peaks at 342, 485, 701 and 1095 cm -1 A peak was observed at 701 cm -1 The intensity of the peak at 342 cm -1 is 6.8 times the intensity of the peak at 1095 cm-1 The intensity of the peak at 342 cm -1 The intensity of the peak was 3.2 times that of the peak at

[0231] The X-ray diffraction pattern and scanning electron microscope image of catalyst S15 were similar to those shown in Figures 3 and 4, respectively.

[0232] Catalyst S15 had a silicon-titanium molar ratio of 37 and a boron-silicon molar ratio of 0.025.

[0233] Catalyst S15 has a micropore volume of 0.15 cm 3 / g, the ratio of the micropore volume to the total pore volume was 7.5%, and the mechanical strength was 64 N / cm.

[0234] Example 16 (1) 90 g of Ti-MWW molecular sieve powder with a silicon-titanium molar ratio of 20, 90 g of amorphous binder (the amorphous binder contained 75 g of silica sol with a mass fraction of 40% silica and 15 g of boric acid), 3 g of sesbania powder, and 9 g of sodium fluoride were mixed under mechanical stirring, and 80 g of water was added. After 4 hours of stirring and kneading, a solid mixture was obtained. This solid mixture was mechanically extruded, dried at 100°C for 8 hours, and calcined at 550°C for 6 hours to obtain a cylindrical molded product.

[0235] (2) 90 g of the cylindrical molding from step (1) was placed on 60 g of a 3 mol / L piperidine solution without contacting it, and crystallized in a sealed environment at 170°C for 2 days. The product was washed with water and dried at 100°C for 8 hours to obtain a cylindrical catalyst precursor A.

[0236] (3) 60 g of the cylindrical catalyst precursor A from step (2) and a 2 mol / L nitric acid solution were mixed in a mass ratio of 1:50, reacted at 80°C for 24 hours, washed with water, dried at 100°C for 8 hours, and calcined at 550°C for 6 hours to obtain a cylindrical catalyst precursor B.

[0237] (4) 40 g of the cylindrical catalyst precursor B from step (3), sodium fluoride, and 0.3 mol / L piperidine solution were mixed in a mass ratio of 1:0.05:20 and reacted at 130°C for 48 hours. The mixture was washed with water and dried at 100°C for 8 hours to obtain the Ti-MWW molecular sieve catalyst, which was recorded as S16.

[0238] Catalyst S16 was tested as above.

[0239] The X-ray photoelectron spectrum of catalyst S16 showed peaks at 458.9, 460.3, 464.8, and 465.9 eV.

[0240] The UV Raman spectrum of catalyst S16 shows peaks at 344, 482, 698 and 1098 cm -1 It showed a peak at 698 cm -1 The intensity of the peak at 344 cm -1 is 3.3 times the intensity of the peak at 1098 cm -1 The intensity of the peak at 344 cm -1 It was 6.9 times the peak value in

[0241] The X-ray diffraction pattern and scanning electron microscope image of catalyst S16 were similar to those shown in Figures 3 and 4, respectively.

[0242] Catalyst S16 had a silicon-titanium molar ratio of 36 and a boron-silicon molar ratio of 0.01.

[0243] Catalyst S16 has a micropore volume of 0.03 cm 3 / g, the ratio of the micropore volume to the total pore volume was 1%, and the mechanical strength was 57 N / cm.

[0244] Working Examples 17-24 In the presence of the Ti-MWW molecular sieve catalysts prepared in Examples 1, 2, 3, 6, 11, 12, 15 and 16, liquid phase continuous epoxidation of propylene was carried out to evaluate the catalytic performance.

[0245] Two grams of the Ti-MWW molecular sieve catalyst was crushed into 20-40 mesh particles and packed into a stainless steel reactor tube. Both ends of the reactor tube were filled with glass beads. The reaction was carried out at 40°C and 2.0 MPa pressure, with the reactor being fed from the bottom and discharged from the top. To ensure complete liquefaction, the propylene pressure was adjusted to 2.5 MPa using nitrogen. The propylene feed solution was fed in portions and recorded as feed solution A. A 15 ppm aqueous solution of piperidine in hydrogen peroxide was prepared using a 30% hydrogen peroxide solution and mixed with acetonitrile solvent. This mixture was recorded as feed solution B. The two feed solutions were fed separately by plunger pumps and premixed before entering the reactor tube. A sample of the mixed feed solution entering the reactor tube was taken and tested as described above. The mixed feed solution flow had a mass fraction of 18.7% propylene and 61.0% acetonitrile, with a molar ratio of propylene to hydrogen peroxide of 1:0.4. The catalyst flow rate per unit mass of the total feed solution was 6 mL g cat -1 h -1 A sample of the reaction mixture was taken from the reaction tube and tested as described above. The results are shown in Table 1.

[0246] [Table 1]

[0247] Notes: a. A sample of the reaction solution was taken just when it came out of the outlet of the reaction tube, and the conversion rate of hydrogen peroxide and the percentage of residual hydrogen peroxide were calculated.

[0248] Working Examples 25-28 The liquid-phase continuous epoxidation of allyl chloride was carried out in the presence of the Ti-MWW molecular sieve catalysts prepared in Examples 1, 6, 11 and 16 to evaluate their catalytic performance.

[0249] Two grams of Ti-MWW molecular sieve catalyst was crushed into 20-40 mesh particles and packed into a stainless steel reactor tube. Both ends of the reactor tube were filled with glass beads. The reaction was conducted at 60 °C and 0.6 MPa pressure, with the reactor being fed from the bottom and discharged from the top. The allyl chloride feed solution was fed in portions and recorded as feed solution A. A 50 ppm aqueous solution of hexamethyleneimine in hydrogen peroxide was prepared using an aqueous solution with a 30% mass fraction of hydrogen peroxide, and this was mixed with acetonitrile solvent. This mixture was recorded as feed solution B. The two feed solutions were fed separately by plunger pumps and premixed before entering the reactor tube. A sample of the mixed feed solution entering the reactor tube was taken and tested as described above. The mixed feed solution stream contained 27.7% allyl chloride and 54.2% acetonitrile by mass, with a molar ratio of allyl chloride to hydrogen peroxide of 1:0.4. The catalyst flow rate per unit mass of the total feed solution is 4 mL g cat -1 h -1 A sample of the reaction mixture was taken from the reaction tube and tested as described above. The results are shown in Table 2.

[0250] [Table 2]

[0251] Notes: a. A sample of the reaction solution was taken just when it came out of the outlet of the reaction tube to calculate the conversion of hydrogen peroxide and the percentage of residual hydrogen peroxide.

[0252] Comparative Example 1 (1) 90 g of Ti-MWW molecular sieve powder with a silicon-titanium molar ratio of 20, 90 g of amorphous binder (the amorphous binder contained 75 g of silica sol with a mass fraction of 40% silica and 15 g of boric acid), 3 g of sesbania powder, and 9 g of sodium fluoride were mixed under mechanical stirring, and 80 g of water was added. After 4 hours of stirring and kneading, a solid mixture was obtained. This solid mixture was mechanically extruded, dried at 100°C for 8 hours, and calcined at 550°C for 6 hours to obtain a cylindrical molded product.

[0253] (2) 60 g of the cylindrical molding from step (1) and a 2 mol / L nitric acid solution were mixed in a mass ratio of 1:50, reacted at 80°C for 24 hours, washed with water, dried at 100°C for 8 hours, and calcined at 550°C for 6 hours to obtain a cylindrical catalyst precursor.

[0254] (3) 40 g of the cylindrical catalyst precursor from step (2), ammonium fluoride, and 3 mol / L piperidine solution were mixed in a mass ratio of 1:0.1:10 and reacted at 170°C for 24 hours. The mixture was washed with water and dried at 100°C for 8 hours to obtain the Ti-MWW molecular sieve catalyst, which was recorded as D1.

[0255] Catalyst D1 was tested as above.

[0256] The X-ray photoelectron spectrum of D1 is shown in Figure 5 and showed peaks at 459.5 and 465.1 eV, which were assigned to four-coordinate titanium species.

[0257] The UV Raman spectrum of D1 is shown in Figure 6, with peaks at 491 and 1080 cm -1 The peaks at 491 and 1080 cm were not observed. -1 The peak at was assigned to a tetracoordinated titanium species. This result was mainly due to the fact that the catalyst contained amorphous binder that had not yet been converted into molecular sieve components. The presence of the amorphous binder masked the molecular sieve, making it impossible to detect the MWW structure of the molecular sieve by UV Raman analysis.

[0258] The X-ray diffraction pattern of D1 is shown in Figure 7. There were diffraction peaks at 2θ of 3.3°, 6.6°, 7.2°, 7.9°, 9.7°, and 26.1°. The intensity of the diffraction peak at 2θ of 7.2° reached approximately 2500, which was significantly weaker than that of S1, indicating that most of D1 retained the MWW structure, but with a low degree of crystallinity. In addition, a more intense broad diffraction peak was observed in the 17.5–30° region, further indicating the presence of amorphous species in D1.

[0259] Scanning electron microscope images are shown in Figure 8. The catalyst exhibited a lamellar morphology, and nanoparticles were observed. Furthermore, the presence of amorphous species in D1 was demonstrated, which was consistent with the results shown in Figure 7.

[0260] D1 had a silicon-titanium molar ratio of 30 and a boron-silicon molar ratio of 0.06.

[0261] D1 has a micropore volume of 0.04 cm 3 / g, the ratio of the micropore volume to the total pore volume was 1.4%, and the mechanical strength was 29 N / cm.

[0262] Comparative Example 2 (1) 90 g of Ti-MWW molecular sieve powder with a silicon-titanium molar ratio of 20, 90 g of amorphous binder (the amorphous binder contained 75 g of silica sol with a mass fraction of 40% silica and 15 g of boric acid), 3 g of sesbania powder, and 9 g of sodium fluoride were mixed under mechanical stirring, and 80 g of water was added. After 4 hours of stirring and kneading, a solid mixture was obtained. This solid mixture was mechanically extruded, dried at 100°C for 8 hours, and calcined at 550°C for 6 hours to obtain a cylindrical molded product.

[0263] (2) 90 g of the cylindrical molding from step (1) was placed on 60 g of a 3 mol / L piperidine solution without contacting it, and crystallized in a sealed environment at 170°C for 2 days. The product was washed with water and dried at 100°C for 8 hours to obtain a cylindrical catalyst precursor.

[0264] (3) 40 g of the cylindrical catalyst precursor from step (2), ammonium fluoride, and 3 mol / L piperidine solution were mixed in a mass ratio of 1:0.1:10 and reacted at 170°C for 24 hours. The mixture was washed with water and dried at 100°C for 8 hours to obtain the Ti-MWW molecular sieve catalyst, which was recorded as D2.

[0265] Catalyst D2 was tested as above.

[0266] The X-ray photoelectron spectrum of D2 was observed to show peaks at 460.0 and 465.6 eV, which were assigned to framework tetracoordinated titanium species.

[0267] The UV Raman spectrum of D2 is shown in Figure 9, with peaks at 342, 491 and 1090 cm -1 A peak was observed at 1090cm -1 The intensity of the peak at 342 cm -1 The peak was 11.2 times that of the peak in the tetrahedral structure, indicating the presence of a large amount of framework tetrahedral titanium species.

[0268] The X-ray diffraction pattern and scanning electron microscope image of D2 were similar to those shown in Figures 3 and 4, respectively.

[0269] D2 had a silicon-titanium molar ratio of 31 and a boron-silicon molar ratio of 0.05.

[0270] D2 has a micropore volume of 0.08 cm 3 / g, the ratio of the micropore volume to the total pore volume was 3.2%, and the mechanical strength was 68 N / cm.

[0271] Comparative Example 3 (1) 90 g of Ti-MWW molecular sieve powder with a silicon-titanium molar ratio of 20, 90 g of amorphous binder (the amorphous binder contained 75 g of silica sol with a mass fraction of 40% silica and 15 g of boric acid), 3 g of sesbania powder, and 9 g of sodium fluoride were mixed under mechanical stirring, and 80 g of water was added. After 4 hours of stirring and kneading, a solid mixture was obtained. This solid mixture was mechanically extruded, dried at 100°C for 8 hours, and calcined at 550°C for 6 hours to obtain a cylindrical molded product.

[0272] (2) 90 g of the cylindrical molding from step (1) was placed on 60 g of a 3 mol / L piperidine solution without contacting it, and crystallized in a sealed environment at 170°C for 2 days. The product was washed with water and dried at 100°C for 8 hours to obtain a cylindrical catalyst precursor.

[0273] (3) 60 g of the cylindrical catalyst precursor from step (2) and 2 mol / L nitric acid solution were mixed in a mass ratio of 1:50, reacted at 80 °C for 24 h, washed with water, dried at 100 °C for 8 h, and calcined at 550 °C for 6 h to obtain the Ti-MWW molecular sieve catalyst, which was recorded as D3.

[0274] Catalyst D3 was tested as above.

[0275] The X-ray photoelectron spectrum of D3 was observed to show peaks at 460.0 and 465.6 eV, which were assigned to framework tetracoordinated titanium species.

[0276] The UV Raman spectrum of D3 is shown in Figure 10, with peaks at 343, 490 and 1092 cm -1 A peak was observed at 1092 cm -1 The intensity of the peak at 343 cm -1 The peak was 10.2 times that of the peak in the tetrahedral structure, indicating the presence of a large amount of framework tetrahedral titanium species.

[0277] The X-ray diffraction pattern and scanning electron microscope image of D3 were similar to those shown in Figures 3 and 4, respectively.

[0278] D3 had a silicon-titanium molar ratio of 36 and a boron-silicon molar ratio of 0.017.

[0279] D3 has a micropore volume of 0.16 cm 3 / g, the ratio of the micropore volume to the total pore volume was 7.8%, and the mechanical strength was 58 N / cm.

[0280] Comparative Example 4 (1) 90 g of Ti-MWW molecular sieve powder with a silicon-titanium molar ratio of 20, 90 g of amorphous binder (the amorphous binder contained 75 g of silica sol with a mass fraction of 40% silica and 15 g of boric acid), and 3 g of sesbania powder were mixed under mechanical stirring, and 80 g of water was added to the mixture. After 4 hours of stirring and kneading, a solid mixture was obtained. This solid mixture was mechanically extruded, dried at 100°C for 8 hours, and calcined at 550°C for 6 hours to obtain a cylindrical molded product.

[0281] (2) 90 g of the cylindrical molding from step (1) was placed on 60 g of a 3 mol / L piperidine solution without contacting it, and crystallized in a sealed environment at 170°C for 2 days. The product was washed with water and dried at 100°C for 8 hours to obtain a cylindrical catalyst precursor A.

[0282] (3) 60 g of the cylindrical catalyst precursor A from step (2) and a 2 mol / L nitric acid solution were mixed in a mass ratio of 1:50, reacted at 80°C for 24 hours, washed with water, dried at 100°C for 8 hours, and calcined at 550°C for 6 hours to obtain a cylindrical catalyst precursor B.

[0283] (4) 40 g of the cylindrical catalyst precursor B from step (3), ammonium fluoride, and 3 mol / L piperidine solution were mixed in a mass ratio of 1:0.1:10 and reacted at 170°C for 24 hours. The mixture was washed with water and dried at 100°C for 8 hours to obtain a Ti-MWW molecular sieve catalyst, which was recorded as D4.

[0284] Catalyst D4 was tested as described above.

[0285] The X-ray photoelectron spectrum of D4 was observed to show peaks at 459.7 and 465.4 eV, which were assigned to four-coordinate titanium species.

[0286] The UV Raman spectrum of D4 is shown in Figure 11 and shows peaks at 340, 488 and 1087 cm -1 A peak was observed at 1087cm -1 The intensity of the peak at 340 cm -1The peak was 10.9 times that of the peak in Fig. 1, indicating the presence of a large amount of tetracoordinated titanium species.

[0287] The X-ray diffraction pattern and scanning electron microscope image of D4 were similar to those shown in Figures 7 and 8, respectively.

[0288] D4 had a silicon-titanium molar ratio of 33 and a boron-silicon molar ratio of 0.012.

[0289] D4 has a micropore volume of 0.05 cm 3 / g, the ratio of the micropore volume to the total pore volume was 1.7%, and the mechanical strength was 36 N / cm.

[0290] Comparative Example 5 (1) 90 g of Ti-MWW molecular sieve powder with a silicon-titanium molar ratio of 20, 90 g of amorphous binder (the amorphous binder contained 75 g of silica sol with a mass fraction of 40% silica and 15 g of boric acid), 3 g of sesbania powder, and 9 g of sodium fluoride were mixed under mechanical stirring, and 80 g of water was added. After 4 hours of stirring and kneading, a solid mixture was obtained. This solid mixture was mechanically extruded, dried at 100°C for 8 hours, and calcined at 550°C for 6 hours to obtain a cylindrical molded product.

[0291] (2) 90 g of the cylindrical molding from step (1) was placed on 60 g of a 3 mol / L piperidine solution without contacting it, and crystallized in a sealed environment at 170°C for 2 days. The product was washed with water and dried at 100°C for 8 hours to obtain a cylindrical catalyst precursor A.

[0292] (3) 60 g of the cylindrical catalyst precursor A from step (2) and a 2 mol / L nitric acid solution were mixed in a mass ratio of 1:50, reacted at 80°C for 24 hours, washed with water, dried at 100°C for 8 hours, and calcined at 550°C for 6 hours to obtain a cylindrical catalyst precursor B.

[0293] (4) 40 g of the cylindrical catalyst precursor B from step (3) and 3 mol / L piperidine solution were mixed in a mass ratio of 1:10 and reacted at 170°C for 24 hours. The mixture was washed with water and dried at 100°C for 8 hours to obtain the Ti-MWW molecular sieve catalyst, which was recorded as D5.

[0294] Catalyst D5 was tested as above.

[0295] The X-ray photoelectron spectrum of D5 was observed to show peaks at 460.6 and 466.2 eV, which were assigned to four-coordinate titanium species.

[0296] The UV Raman spectrum of D5 is shown in Figure 12, with peaks at 342, 490 and 1102 cm -1 A peak was observed at 1102 cm -1 The intensity of the peak at 342 cm -1 The peak was 10.3 times that of the peak in Fig. 1, indicating the presence of a large amount of framework tetracoordinate titanium species.

[0297] The X-ray diffraction pattern and scanning electron microscope image of D5 were similar to those shown in Figures 3 and 4, respectively.

[0298] D5 had a silicon-titanium molar ratio of 36 and a boron-silicon molar ratio of 0.017.

[0299] D5 has a micropore volume of 0.04 cm 3 / g, the ratio of the micropore volume to the total pore volume was 1.3%, and the mechanical strength was 74 N / cm.

[0300] Comparative Example 6 (1) 90 g of Ti-MWW molecular sieve powder with a silicon-titanium molar ratio of 20, 90 g of amorphous binder (the amorphous binder contained 75 g of silica sol with a mass fraction of 40% silica and 15 g of boric acid), 3 g of sesbania powder, and 9 g of sodium fluoride were mixed under mechanical stirring, and 80 g of water was added thereto. After 4 hours of stirring and kneading, a solid mixture was obtained. The solid mixture was subjected to mechanical extrusion molding, dried at 100°C for 8 hours, and calcined at 550°C for 6 hours to obtain a cylindrical molding, which was recorded as D6.

[0301] Catalyst D6 was tested as above.

[0302] The X-ray photoelectron spectrum of D6 is shown in Figure 13 and showed peaks at 460.2 and 465.8 eV, which were assigned to four-coordinate titanium species.

[0303] The UV Raman spectrum of D6 is shown in Figure 14, with peaks at 343, 492 and 1094 cm -1 A peak was observed at 1094 cm -1 The intensity of the peak at 343 cm -1 The peak was 9.7 times that of the peak in Fig. 1, indicating the presence of a large amount of framework tetracoordinate titanium species.

[0304] The X-ray photoelectron spectrum and UV Raman spectrum of the Ti-MWW molecular sieve powder were similar to those in Figures 13 and 14, respectively, indicating that the mechanical extrusion molding did not affect the state of titanium species in catalyst D6.

[0305] The X-ray diffraction pattern and scanning electron microscope image of D6 were similar to those shown in Figures 7 and 8, respectively.

[0306] D6 had a silicon-titanium molar ratio of 38 and a boron-silicon molar ratio of 0.11.

[0307] D6 has a micropore volume of 0.13 cm 3 / g, the ratio of the micropore volume to the total pore volume was 5.4%, and the mechanical strength was 28 N / cm.

[0308] Comparative Example 7 (1) 90 g of Ti-MWW molecular sieve powder with a silicon-titanium molar ratio of 20, 90 g of amorphous binder (the amorphous binder contained 75 g of silica sol with a mass fraction of 40% silica and 15 g of boric acid), 3 g of sesbania powder, and 9 g of sodium fluoride were mixed under mechanical stirring, and 80 g of water was added thereto. After 4 hours of stirring and kneading, a solid mixture was obtained. The solid mixture was subjected to mechanical extrusion molding, dried at 100°C for 8 hours, and calcined at 550°C for 6 hours to obtain a cylindrical molding, which was recorded as D7.

[0309] Catalyst D7 was tested as above.

[0310] The X-ray photoelectron spectrum of D7 is shown in Figure 15 and showed peaks at 458.0 and 463.8 eV, which were assigned to extraframework hexacoordinated titanium species.

[0311] The UV Raman spectrum of D7 is shown in Figure 16, with peaks at 440 and 700 cm -1 These peaks were assigned to exoframework hexacoordinated titanium species.

[0312] The X-ray photoelectron spectrum and UV Raman spectrum of the as-synthesized Ti-MWW molecular sieve powder were similar to Figures 15 and 16, respectively, indicating that the shaping by mechanical extrusion did not affect the state of titanium species in catalyst D7.

[0313] The X-ray diffraction pattern and scanning electron microscope image of D7 were similar to those shown in Figures 7 and 8, respectively.

[0314] D7 had a silicon-titanium molar ratio of 37 and a boron-silicon molar ratio of 0.12.

[0315] The volume of the micropores in D7 is 0.12 cm 3 / g, the ratio of the micropore volume to the total pore volume was 5.3%, and the mechanical strength was 26 N / cm.

[0316] Comparison work examples 8-11 Working Examples 17 to 24 were repeated using Ti-MWW molecular sieve catalysts D1 to D7 obtained in Comparative Examples 1 to 7, respectively, to evaluate their catalytic performance, and the results are shown in Table 3 below.

[0317] [Table 3]

[0318] Notes: a. A sample of the reaction solution was taken just when the reaction solution was coming out of the outlet of the reaction tube, and the percentage of hydrogen peroxide conversion and residual hydrogen peroxide was calculated.

[0319] The embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the technical scope of the present invention, various simple modifications can be made to the embodiments of the present invention, including combining various technical features in any other suitable manner. These simple modifications and combinations are also the contents disclosed in this specification and should be considered to be within the protection scope of the present disclosure. [Brief explanation of the drawings]

[0320] [Figure 1] 1 is an X-ray photoelectron spectrum of the Ti-MWW molecular sieve catalyst obtained in Example 1. [Figure 2] 1 is a UV Raman spectrum of the Ti-MWW molecular sieve catalyst obtained in Example 1. [Figure 3] 1 is an X-ray diffraction pattern of the Ti-MWW molecular sieve catalyst obtained in Example 1. [Figure 4] 1 is a scanning electron microscope image of the Ti-MWW molecular sieve catalyst obtained in Example 1. [Figure 5] 1 is an X-ray photoelectron spectrum of the Ti-MWW molecular sieve catalyst obtained in Comparative Example 1. [Figure 6] 1 is a UV Raman spectrum of the Ti-MWW molecular sieve catalyst obtained in Comparative Example 1. [Figure 7] 1 is an X-ray diffraction pattern of the Ti-MWW molecular sieve catalyst obtained in Comparative Example 1. [Figure 8] 1 is a scanning electron microscope image of the Ti-MWW molecular sieve catalyst obtained in Comparative Example 1. [Figure 9] 1 is a UV Raman spectrum of the Ti-MWW molecular sieve catalyst obtained in Comparative Example 2. [Figure 10] : UV Raman spectrum of the Ti-MWW molecular sieve catalyst obtained in Comparative Example 3. [Figure 11] 1 is a UV Raman spectrum of the Ti-MWW molecular sieve catalyst obtained in Comparative Example 4. [Figure 12] 1 is a UV Raman spectrum of the Ti-MWW molecular sieve catalyst obtained in Comparative Example 5. [Figure 13] 1 is an X-ray photoelectron spectrum of the Ti-MWW molecular sieve catalyst obtained in Comparative Example 6. [Figure 14] 1 is a UV Raman spectrum of the Ti-MWW molecular sieve catalyst obtained in Comparative Example 6. [Figure 15] 1 is an X-ray photoelectron spectrum of the Ti-MWW molecular sieve catalyst obtained in Comparative Example 7. [Figure 16] 1 is a UV Raman spectrum of the Ti-MWW molecular sieve catalyst obtained in Comparative Example 7.

Claims

1. A Ti-MWW molecular sieve catalyst, The X-ray photoelectron energy spectrum of the catalyst comprises peaks at 458.9±0.2 eV and 464.8±0.2 eV, preferably 458.9±0.1 eV and 464.8±0.1 eV; Preferably, the X-ray photoelectron energy spectrum of said catalyst comprises peaks at 458.9±0.2 eV, 460.3±0.2 eV, 464.8±0.2 eV and 465.9±0.2 eV, preferably 458.9±0.1 eV, 460.3±0.1 eV, 464.8±0.1 eV and 465.9±0.1 eV.

2. The UV Raman spectrum of the catalyst was 343±4 cm －１ , 484±4 cm －１ , 699±4 cm －１ and 1097 ± 4 cm －１ Contains peaks at Preferably, 699±4 cm －１ The intensity of the peak at 343±4 cm －１ 0.5 to 10 times, preferably 2 to 10 times, the intensity of the peak at 1097±4 cm －１ The intensity of the peak at 343±4 cm －１ 2. The catalyst according to claim 1, characterized in that the intensity of the peak in the graph is 0.5 to 10 times, preferably 2 to 10 times, that of the peak in the graph.

3. 2. The catalyst according to claim 1, characterized in that the catalyst has a molar ratio of silicon to titanium of 10 to 200, preferably 25 to 100, the catalyst further comprises at least one element of boron and aluminum, preferably boron, the catalyst has a molar ratio of boron to silicon of 0 to 0.1, preferably 0 to 0.03, more preferably 0.005 to 0.03, and the catalyst has a molar ratio of aluminum to silicon of 0 to 0.1, preferably 0 to 0.

05.

4. The catalyst has a thickness of 0.03 to 0.15 cm ３ / g, preferably 0.03 to 0.12 cm ３ / g, more preferably 0.05 to 0.10 cm ３ 2. The catalyst according to claim 1, characterized in that it has a volume of micropores of 1 to 7.5%, preferably 1 to 6%, more preferably 1.7 to 5% of the total pore volume.

5. Catalyst according to claim 1, characterized in that the catalyst is of perfect crystalline structure and preferably the catalyst has a mechanical strength of 30 to 90 N / cm, preferably 40 to 80 N / cm.

6. A method for preparing a Ti-MWW molecular sieve catalyst, comprising the steps of: (1) forming and firing a Ti-MWW molecular sieve powder, a binder, a pore-forming agent, and a fluoride to obtain a formed product; (2) a step of crystallizing the formed product of the step (1) in the presence of an organic amine solution to obtain a catalyst precursor A; (3) a step of treating the catalyst precursor A from the step (2) with an acid solution and calcining it to obtain a catalyst precursor B; (4) A step of treating the catalyst precursor B of the step (3) with an organic amine solution to obtain the catalyst.

7. 7. The method of claim 6, wherein the binder comprises a silicon source and at least one selected from the group consisting of a boron source and an aluminum source, and the silicon source, the boron source, and the aluminum source are in a molar ratio of 1:x:y, on an oxide basis, where x=0 to 0.5, y=0 to 0.5, and x+y=0.02 to 1.

8. 8. The method according to claim 7, wherein the silicon source is at least one selected from the group consisting of silica sol, sodium silicate, white carbon black, and ethyl orthosilicate, the boron source is at least one selected from the group consisting of boric acid, boron oxide, and borate salts, and the aluminum source is at least one selected from the group consisting of aluminum oxide, aluminum hydroxide, sodium metaaluminate, aluminum nitrate, and aluminum sulfate.

9. 9. The method according to claim 6, wherein the pore-forming agent is at least one selected from the group consisting of sesbania powder, cellulose, chitosan, lignin, starch, polyethylene glycol, poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer (P123) and poly(ethylene oxide)-poly(propylene oxide) copolymer (F127); the fluoride is at least one selected from the group consisting of sodium fluoride, potassium fluoride and ammonium fluoride; and the Ti-MWW molecular sieve powder, the binder, the pore-forming agent and the fluoride are used in a mass ratio of 1:(0.1-1.5):(0.01-0.1):(0.01-0.4).

10. 7. The method according to claim 6, wherein step (2) comprises placing the shaped product of step (1) on the organic amine solution without contacting it with the organic amine solution, the organic amine being at least one selected from the group consisting of piperidine and hexamethyleneimine, the organic amine solution having a concentration of 0.3 to 15 mol / L, the shaped product and the organic amine solution being used in a mass ratio of (0.1 to 10):1, and the crystallization is carried out at a temperature of 130 to 190°C for 1 to 9 days.

11. The method according to claim 6, wherein step (3) comprises contacting and reacting the catalyst precursor A of step (2) with the acid solution, the acid solution being at least one selected from the group consisting of solutions of nitric acid, hydrochloric acid, sulfuric acid, formic acid, acetic acid, and oxalic acid, the concentration of the acid solution being 0.3 to 12 mol / L, the catalyst precursor A and the acid solution being used in a mass ratio of 1:(10 to 80), and the treatment with the acid solution being carried out at a temperature of 60 to 130°C for 4 to 48 hours.

12. 7. The method according to claim 6, wherein step (4) comprises contacting and reacting the catalyst precursor B of step (3) with the organic amine solution in the presence of a fluoride, wherein the fluoride is at least one selected from the group consisting of sodium fluoride, potassium fluoride, and ammonium fluoride, the organic amine is at least one selected from the group consisting of piperidine and hexamethyleneimine, the concentration of the organic amine solution is 0.3 to 15 mol / L, the catalyst precursor B, the fluoride, and the organic amine solution are in a mass ratio of 1:(0.05 to 0.4):(2 to 20), and the treatment with the organic amine solution is carried out at a temperature of 130 to 190°C for 4 to 48 hours.

13. 7. The method according to claim 6, wherein in step (1), the firing is carried out in an oxygen-containing atmosphere at 450 to 650°C for 4 to 12 hours, and in step (3), the firing is carried out in an oxygen-containing atmosphere at 450 to 650°C for 4 to 12 hours.

14. A catalyst prepared by the method of any one of claims 5 to 13.

15. Use of the catalyst according to any one of claims 1 to 5 or the catalyst according to claim 14 in the epoxidation of olefins.

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