Ti-MWW MOLECULAR SIEVE-CONTAINING CATALYST, ITS MANUFACTURING METHOD AND ITS APPLICATION

Abstract

FIELD: chemical or physical processes.SUBSTANCE: present invention relates to the field of technology of catalysts containing a titanium silicate molecular sieve, in particular, to a catalyst containing a Ti-MWW molecular sieve, its manufacture and application. A Ti-MWW molecular sieve containing catalyst for the epoxidation of olefins is disclosed, the X-ray photoelectron energy spectrum of which exhibits peaks at 458.9±0.2 eV and 464.8±0.2 eV, 458.9±0.1 eV, 460.3±0.1 eV, 464.8±0.1 eV and 465.9±0.1 eV.EFFECT: high degree of conversion with respect to olefins, high selectivity with respect to epoxides and good catalytic stability.16 cl, 16 dwg, 3 tbl, 42 ex

Description

[0001] Field of technology to which the present invention pertains

[0002] The present invention relates to the technical field of titanosilicate molecular sieve-containing catalysts, in particular, to a Ti-MWW molecular sieve-containing catalyst, its manufacture and use.

[0003] Background Art of the Present Invention

[0004] Epoxides are important organic chemical materials; mainly, epoxides are ethylene oxide, propylene oxide, 1-pentene oxide, 1-hexene oxide, etc. Currently, epoxides are mainly produced by the selective oxidation of olefins. EniChem has developed a method for producing propylene oxide, known as the introduction of hydrogen peroxide into propylene oxide (HPPO) (see, for example, US4410501A). In this method, propylene oxide is produced by the reaction of propylene and hydrogen peroxide in a methanol solvent using titanosilicate molecular sieve TS-1, which has an MFI structure, as a catalyst. This method, which has the advantages of being environmentally friendly and having a high utilization rate of raw materials, has been put into industrial production.However, since the TS-1 molecular sieve has 10-membered ring channels with dimensions of approximately 0.5 nm and, thus, is insufficient for the diffusion of large molecules, significant problems may arise during the epoxidation of cyclohexene, which has somewhat larger molecules. To address these problems, Professor Wu Peng and his co-workers developed a new generation of titanosilicate molecular sieves (Ti-MWW) (see Journal of Catalysis, 2001, 202, 245). Compared with the TS-1 molecular sieve, the Ti-MWW molecular sieve provides not only a higher conversion for olefins but also a higher selectivity for epoxides.

[0005] Currently, industrial production of propylene oxide is primarily carried out in fixed-bed reactors. Titanosilicate molecular sieves produced by the hydrothermal method are powders with particle sizes in the micron or nanometer range and lack mechanical strength. When directly loaded into fixed-bed reactors, they can be entrained in the reaction fluids during the reaction, leading to clogging. Furthermore, it is very difficult to separate and recover the titanosilicate molecular sieve powder from the reaction fluids after the reaction. To ensure efficient and continuous operation of the fixed-bed reactor, the titanosilicate molecular sieve powder must be converted into a catalyst with high mechanical strength.

[0006] Patent CN 1346705 A proposes using small beads with a certain mechanical strength as carriers and enriching the titanosilicate molecular sieves on the surface of the beads through molding in the spheronization process. This increases the mechanical strength of the resulting catalyst. Patent CN 112354557 A discloses the manufacture and use of an integral titanozeolite catalyst. The integral catalyst for the continuous epoxidation of propylene is prepared by mixing an amorphous silicon-based binder and a polymeric pore-forming agent with MWW titanium zeolite powder, adding water, mixing and stirring, mechanically molding and calcining, immersing in an aqueous solution of a cyclic nitrogen-containing organic composite, sealing, heating, filtering, drying, and calcining.

[0007] In general, prior art Ti-MWW molecular sieve-containing catalysts, regardless of whether they contain binders, suffer from low mechanical strength and poor catalytic performance. Theoretically, the composition and structure of prior art Ti-MWW molecular sieve-containing catalysts can be modified to further improve their mechanical strength and catalytic performance. Therefore, there is a constant need in the art to develop Ti-MWW molecular sieve-containing catalysts with high mechanical strength and good catalytic performance.

[0008] Brief Disclosure of the Present Invention

[0009] The objective of the present invention is to overcome the problems of the prior art, such as low mechanical strength and poor catalytic performance of Ti-MWW molecular sieve-containing catalysts. The present invention provides a Ti-MWW molecular sieve-containing catalyst, a method for producing the same, and its use. The Ti-MWW molecular sieve-containing catalyst according to the present invention contains titanium particles in an appropriate state, preferably existing entirely in the form of a crystalline structure, and as a result, it offers the advantages of high mechanical strength and excellent catalytic performance.

[0010] In order to achieve the above-mentioned object, according to the first aspect of the present invention, there is provided a Ti-MWW molecular sieve-containing catalyst, wherein the X-ray photoelectron energy spectrum of the catalyst includes peaks at 458.9±0.2 eV and 464.8±0.2 eV, preferably at 458.9±0.1 eV and 464.8±0.1 eV; preferably, the X-ray photoelectron energy spectrum of the catalyst contains peaks at 458.9±0.2 eV, 460.3±0.2 eV, 464.8±0.2 eV and 465.9±0.2 eV, preferably at 458.9±0.1 eV, 460.3±0.1 eV, 464.8±0.1 eV and 465.9±0.1 eV.

[0011] According to a second aspect of the present invention, there is provided a method for producing a Ti-MWW molecular sieve-containing catalyst, comprising the following steps:

[0012] (1) directing the Ti-MWW molecular sieve powder, binder, pore-forming agent and fluoride to molding and calcination to obtain a molded product;

[0013] (2) crystallizing the molded product obtained in step (1) in the presence of an organic amine solution to obtain a catalyst precursor A;

[0014] (3) treating the catalyst precursor A obtained in step (2) with an acid solution and calcining to obtain the catalyst precursor B;

[0015] (4) treating the catalyst precursor B obtained in step (3) with an organic amine solution to obtain a catalyst.

[0016] At the same time, according to the present invention, there is provided a Ti-MWW molecular sieve-containing catalyst produced by the above-described method.

[0017] Furthermore, the present invention provides the use of a Ti-MWW molecular sieve-containing catalyst in the epoxidation of olefins. The present invention may include the following items as examples.

[0018] 1. A fully crystalline Ti-MWW molecular sieve catalyst which has peaks at 343±4 cm in its ultraviolet Raman spectrum -1 , 484±4 cm -1 , 699±4 cm -1 and 1097±4 cm -1 , in which the peak intensity at 699±4 cm -1 is 0.5-10 times, preferably 2-10 times, the peak intensity at 343±4 cm -1 , and in which the peak intensity at 1097±4 cm -1 is 0.5-10 times, preferably 2-10 times, the peak intensity at 343±4 cm -1 .

[0019] 2. The molecular sieve-containing catalyst according to item 1, characterized in that the molar ratio of silicon to titanium in the molecular sieve-containing catalyst is 10-200, preferably 25-100; the molecular sieve-containing catalyst further contains at least one element of boron and aluminum, preferably boron; the molar ratio of boron to silicon in the molecular sieve-containing catalyst is 0-0.1, preferably 0-0.03, more preferably 0.005-0.03; the molar ratio of aluminum to silicon in the molecular sieve-containing catalyst is 0-0.1, preferably 0-0.05.

[0020] 3. The molecular sieve-containing catalyst according to item 1, characterized in that the molecular sieve-containing catalyst has a micropore volume of 0.03-0.15 cm 3 / g, preferably 0.03-0.12 cm 3 / g, preferably 0.05-0.10 cm 3 / g; wherein the proportion of micropore volume in relation to the total pore volume is 1%-7.5%, preferably 1-6%, more preferably 1.7%-5%.

[0021] 4. The molecular sieve-containing catalyst according to claim 1, characterized in that the molecular sieve-containing catalyst has a mechanical strength of 30-90 N / cm, preferably 40-80 N / cm.

[0022] 5. A method for producing a fully crystalline Ti-MWW molecular sieve-containing catalyst, comprising the following steps:

[0023] (1) directing the powdered Ti-MWW molecular sieve, binder, pore-forming agent and fluoride to mixing, molding and calcining to obtain a molded product;

[0024] (2) crystallizing the molded product obtained in step (1) in an organic amine solution medium to obtain a catalyst precursor A;

[0025] (3) treating the catalyst precursor A obtained in step (2) with an acid solution and calcining to obtain the catalyst precursor B;

[0026] (4) treating the catalyst precursor B obtained in step (3) with an organic amine solution to obtain a molecular sieve-containing catalyst.

[0027] 6. The method according to paragraph 5, characterized in that the binder in step (1) contains a silicon source and at least one substance selected from the group consisting of a boron source and an aluminum source; wherein the binder includes ingredients in such a way that, in terms of the oxides SiO2, B2O3 and Al2O3, the substances are present in a molar ratio of 1:x:y, where x=0-0.5, y=0-0.5, and x+y=0.02-1.

[0028] 7. The method according to paragraph 6, characterized in that the silicon source is at least one substance selected from the group consisting of silicon dioxide sol, sodium silicate, white carbon black and ethyl orthosilicate; the boron source is at least one substance selected from the group consisting of boric acid, boron oxide and borates; the aluminum source is at least one substance selected from the group consisting of aluminum oxide, aluminum hydroxide, sodium metaaluminate, aluminum nitrate and aluminum sulfate.

[0029] 8. The method according to any one of items 5 to 7, characterized in that the pore-forming substance in step (1) is at least one substance selected from the group consisting of sesbania powder, cellulose, chitosan, lignin, starch, polyethylene glycol, triblock copolymers P123 and F127; the fluoride in step (1) is at least one substance selected from the group consisting of sodium fluoride, potassium fluoride and ammonium fluoride; in the composition of the starting materials in step (1), the powdered Ti-MWW molecular sieve, the binder, the pore-forming substance and the fluoride are present in a weight ratio of 1:0.1 - 1.5:0.01 - 0.1:0.01 - 0.4.

[0030] 9. The method according to paragraph 5, characterized in that the step (2) of crystallization in the medium of the organic amine solution comprises: directing the shaped product obtained in the step (1) to crystallization by placing it on the organic amine solution, wherein the shaped product is not in contact with the organic amine solution; wherein the organic amine is at least one substance selected from the group consisting of piperidine and hexamethyleneimine; the organic amine solution has a concentration of 0.3-15 mol / L; the shaped product and the organic amine solution are present in a weight ratio of 0.1-10:1; and the crystallization is carried out under conditions of a temperature of 130-190°C for 1-9 days.

[0031] 10. The method according to paragraph 5, characterized in that in step (3), the treatment with an acid solution comprises: bringing the catalyst precursor A obtained in step (2) and the acid solution into contact and performing a reaction; wherein the acid solution is at least one substance selected from the group consisting of solutions of nitric acid, hydrochloric acid, sulfuric acid, formic acid, acetic acid and oxalic acid; the acid solution has a concentration of 0.3-12 mol / L; the catalyst precursor A and the acid solution, which are solid and liquid phases, are in a weight ratio of 1:10-80; the treatment with the acid solution is carried out under conditions of a temperature of 60-130°C for 4-48 hours.

[0032] 11. The method according to paragraph 5, characterized in that in step (4), the treatment with an organic amine solution comprises: bringing the catalyst precursor B obtained in step (3), fluoride and the organic amine solution into contact and performing a reaction; wherein the fluoride is at least one substance selected from the group consisting of sodium fluoride, potassium fluoride and ammonium fluoride; the organic amine is at least one substance selected from the group consisting of piperidine and hexamethyleneimine; the organic amine solution has a concentration of 0.3-15 mol / L; the catalyst precursor B, the fluoride and the organic amine solution are present in a weight ratio of 1:0.05-0.4:2-20; the treatment with the organic amine solution is carried out under conditions of a temperature of 130-190°C for 4-48 hours.

[0033] 12. The method according to paragraph 5, characterized in that the calcination in step (1) is carried out under conditions of a temperature of 450-650°C in an oxygen-containing atmosphere for 4-12 hours; the calcination in step (3) is carried out under conditions of a temperature of 450-650°C in an oxygen-containing atmosphere for 4-12 hours.

[0034] 13. A molecular sieve-containing catalyst produced by the method according to any one of items 5 to 12.

[0035] 14. Use of the molecular sieve-containing catalysts according to any one of items 1 to 4 or the molecular sieve-containing catalysts according to item 13 in the epoxidation of olefins.

[0036] Compared with the prior art, the present invention has the following advantages.

[0037] 1. The Ti-MWW molecular sieve-containing catalyst according to the present invention contains a large number of titanium fragments in the appropriate state, including modified extra-framework hexacoordinate titanium fragments, or contains framework tetracoordinate titanium fragments and modified extra-framework hexacoordinate titanium fragments. These titanium fragments in the appropriate state impart improved catalytic performance to the catalyst. In addition, the Ti-MWW molecular sieve-containing catalyst preferably exists entirely in the form of a crystalline structure. This means that the catalyst does not contain any amorphous binder.In other words, the binder does not exist in amorphous form, but is transformed into a MWW molecular sieve and then becomes part of the final catalyst, resulting in a catalyst with a fully crystalline structure. On the one hand, the absence of an amorphous binder prevents the amorphous binder from shielding the catalytic active site and blocking the pores of the molecular sieve, thereby increasing the activity and stability of the catalyst. On the other hand, the fully crystalline structure increases mechanical strength, and the catalyst is less susceptible to fragmentation and loss. When used in olefin epoxidation, the catalyst offers the advantages of high olefin conversion, high epoxide selectivity, and good catalytic stability.

[0038] 2. In the manufacturing method according to the present invention, a preferred amorphous binder contains a silicon source and a boron source, which can be effectively converted into a MWW molecular sieve, thereby ensuring the production of a catalyst having a fully crystalline structure, while improving the catalytic performance and increasing the mechanical strength. In addition, in the manufacturing method, the crystalline catalyst precursor A is treated with an acid solution and an organic amine solution, respectively, which ensures the effective conversion of titanium fragments in the Ti-MWW molecular sieve into titanium fragments in an appropriate state, including modified extra-framework hexacoordinated titanium fragments and, optionally, framework tetracoordinated titanium fragments.The manufacturing method according to the present invention makes it possible to obtain a Ti-MWW molecular sieve-containing catalyst exhibiting excellent catalytic activity, selectivity and stability.

[0039] 3. When used in olefin epoxidation, the catalyst according to the present invention exhibits excellent catalytic performance, high olefin conversion, high epoxide selectivity, good catalytic stability, and thus provides good application prospects.

[0040] Brief description of figures

[0041] Fig. 1 illustrates an X-ray photoelectron spectrum of the Ti-MWW molecular sieve-containing catalyst obtained in Example 1;

[0042] Fig. 2 illustrates the ultraviolet Raman spectrum of the Ti-MWW molecular sieve-containing catalyst obtained in Example 1;

[0043] Fig. 3 illustrates an X-ray diffraction pattern of the Ti-MWW molecular sieve-containing catalyst obtained in Example 1;

[0044] Fig. 4 is a scanning electron microscope image of the Ti-MWW molecular sieve-containing catalyst obtained in Example 1;

[0045] Fig. 5 illustrates an X-ray photoelectron spectrum of the Ti-MWW molecular sieve-containing catalyst obtained in Comparative Example 1;

[0046] Fig. 6 illustrates the ultraviolet Raman spectrum of the Ti-MWW molecular sieve-containing catalyst obtained in Comparative Example 1;

[0047] Fig. 7 illustrates an X-ray diffraction pattern of the Ti-MWW molecular sieve-containing catalyst obtained in Comparative Example 1;

[0048] Fig. 8 is a scanning electron microscope image of the Ti-MWW molecular sieve-containing catalyst obtained in Comparative Example 1;

[0049] Fig. 9 illustrates the ultraviolet Raman spectrum of the Ti-MWW molecular sieve-containing catalyst obtained in Comparative Example 2;

[0050] Fig. 10 illustrates the ultraviolet Raman spectrum of the Ti-MWW molecular sieve-containing catalyst obtained in Comparative Example 3;

[0051] Fig. 11 illustrates the ultraviolet Raman spectrum of the Ti-MWW molecular sieve-containing catalyst obtained in Comparative Example 4;

[0052] Fig. 12 illustrates the ultraviolet Raman spectrum of the Ti-MWW molecular sieve-containing catalyst obtained in Comparative Example 5;

[0053] Fig. 13 illustrates an X-ray photoelectron spectrum of the Ti-MWW molecular sieve-containing catalyst obtained in Comparative Example 6;

[0054] Fig. 14 illustrates the ultraviolet Raman spectrum of the Ti-MWW molecular sieve-containing catalyst obtained in Comparative Example 6;

[0055] Fig. 15 illustrates an X-ray photoelectron spectrum of the Ti-MWW molecular sieve-containing catalyst obtained in Comparative Example 7;

[0056] Fig. 16 illustrates the ultraviolet Raman spectrum of the Ti-MWW molecular sieve-containing catalyst obtained in Comparative Example 7.

[0057] Detailed Disclosure of the Present Invention

[0058] According to the present invention, unless otherwise specified, percentages and proportions are expressed on a weight basis. Unless otherwise specified, in the description and claims of the present invention, the term "comprise" or variations thereof, such as "comprises" or "comprising" and similar terms, shall be understood to mean the inclusion of the stated steps or components, without excluding other steps or other components.

[0059] Except in the examples, all numerical values ​​of parameters in the description of the present invention should be understood as modified in all instances by the term "about", regardless of the actual presence of the term "about" before the corresponding numerical value.

[0060] According to one embodiment of the present invention, there is provided a Ti-MWW molecular sieve-containing catalyst, wherein the X-ray photoelectron energy spectrum of the catalyst includes peaks at 458.9±0.2 eV and 464.8±0.2 eV, preferably at 458.9±0.1 eV and 464.8±0.1 eV; Preferably, the X-ray photoelectron energy spectrum of the catalyst contains peaks at 458.9±0.2 eV, 460.3±0.2 eV, 464.8±0.2 eV, and 465.9±0.2 eV, preferably at 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 correspond to framework tetracoordinated titanium fragments; the peaks at 458.9±0.2 eV and 464.8±0.2 eV correspond to modified extraframework hexacoordinated titanium fragments.

[0061] As used herein, the term "Ti-MWW molecular sieve" means a titanosilicate molecular sieve having a three-dimensional MWW structure. The Ti-MWW molecular sieves may be commercially available molecular sieves or may be manufactured 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). The Ti-MWW molecular sieves produced by the hydrothermal method are referred to herein as "synthesized Ti-MWW molecular sieve powder." The art provides methods for modifying the synthesized Ti-MWW molecular sieve powder to improve their catalytic performance. For example, the synthesized Ti-MWW molecular sieve powder can be treated with acid (see, e.g., Journal of Catalysis, 2001, 202, 245). The synthesized Ti-MWW molecular sieve powder after acid treatment is referred to herein as "Ti-MWW molecular sieve powder".

[0062] The titanium fragments in the Ti-MWW molecular sieve can be present in the forms of framework tetracoordinated titanium fragments, extra-framework hexacoordinated titanium fragments, and titanium dioxide. The synthesized Ti-MWW molecular sieve powder produced by the hydrothermal method may contain a small amount of framework tetracoordinated titanium fragments and a large amount of extra-framework hexacoordinated titanium fragments. Framework tetracoordinated titanium fragments are generally regarded as catalytic active sites for olefin epoxidation, i.e., the so-called "titanium fragments in the appropriate state." However, the extra-framework hexacoordinated titanium fragments and titanium dioxide are not catalytic active sites for olefin epoxidation, i.e., the so-called "titanium fragments in the unsatisfactory state."Prior art literature describes attempts to convert extra-framework hexacoordinated titanium fragments into framework tetracoordinated titanium fragments, thereby improving the catalyst's catalytic performance. The aforementioned acid treatment of the synthesized Ti-MWW molecular sieve powder achieves precisely this transformation.

[0063] The present inventor has unexpectedly discovered that extra-framework hexacoordinated titanium fragments or framework tetracoordinated titanium fragments can be converted into modified extra-framework hexacoordinated titanium fragments. The modification of titanium fragments can be expressed by peaks in the X-ray photoelectron spectra of Ti-MWW molecular sieves. Before modification, the X-ray photoelectron spectrum of the synthesized Ti-MWW molecular sieve powder can contain peaks at 458.0±0.2 eV and 463.8±0.2 eV, which correspond to extra-framework hexacoordinated titanium fragments. Alternatively, the X-ray photoelectron spectrum of the powdered Ti-MWW molecular sieve may contain peaks at 460.3±0.2 eV and 465.9±0.2 eV, which correspond to the framework tetracoordinated titanium fragments.After modification, the X-ray photoelectron spectrum of the Ti-MWW molecular sieve powder may contain peaks at 458.9±0.2 eV and 464.8±0.2 eV, which correspond to the modified extra-framework hexacoordinated titanium fragments. The modified extra-framework hexacoordinated titanium fragments also provide excellent catalytic activity for olefin epoxidation. That is, they also represent titanium fragments in the corresponding state and, as a result, can impart improved catalytic performance to the Ti-MWW molecular sieve-containing catalyst according to the present invention. The present invention was accomplished based on the above-mentioned discovered facts.

[0064] The ultraviolet Raman spectrum of the catalyst preferably contains peaks at 343±4 cm -1 , 484±4 cm -1 , 699±4 cm -1 and 1097±4 cm -1, while the peak intensity at 699±4 cm -1 is 0.5-10 times, preferably 2-10 times, the peak intensity at 343±4 cm -1 , and the peak intensity at 1097±4 cm -1 is 0.5-10 times, preferably 2-10 times, the peak intensity at 343±4 cm -1 . As a rule, the peak is at 343±4 cm -1 corresponds to the MWW frame, peaks at 484±4 cm -1 and 1097±4 cm -1 correspond to framework tetracoordinated titanium fragments, and a peak at 699±4 cm -1 correspond to extra-framework hexacoordinated titanium fragments and / or modified extra-framework hexacoordinated titanium fragments.

[0065] The molar ratio (n) is preferred Si / n Ti ) silicon and titanium in the catalyst is 10-200, preferably 25-100 in terms of atomic quantities.

[0066] 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 0-0.1, preferably 0-0.03, more preferably 0.005-0.03 in terms of atomic quantities. The molar ratio of aluminum to silicon (n Al / n Si ) is 0-0.1, preferably 0-0.03 in terms of atomic quantities.

[0067] Preferably, the catalyst exists in the form of a porous structure and comprises micropores, mesopores, and macropores. The micropores may have a pore size of less than 2 nm, such as 0.4-2 nm; the mesopores may have a pore size of 2-50 nm; the macropores may have a pore size of more than 50 nm, such as 50-500 nm. According to one embodiment, the catalyst has a micropore volume of 0.03-0.15 cm 3 / g, preferably 0.03-0.12 cm 3 / g, preferably 0.05-0.10 cm3 / g. The proportion of micropore volume in relation to the total pore volume is 1-7.5%, preferably 1-6%, more preferably 1.7-5%.

[0068] Preferably, the catalyst exists entirely in the form of a crystalline structure. As used herein, the term “fully crystalline” means that the molecular sieve-containing catalyst is free of, or substantially free of, amorphous binder. The term “substantially free” means that the catalyst contains amorphous binder in an amount of less than 5 weight percent, preferably less than 3 weight percent, and more preferably less than 1 weight percent. The binder is converted into the MWW molecular sieve and thereby becomes part of the resulting catalyst. The fully crystalline structure can be identified using scanning electron microscopy and X-ray diffraction.

[0069] Preferably, the catalyst has a mechanical strength of 30-90 N / cm, preferably 40-80 N / cm.

[0070] According to a further embodiment of the present invention, there is provided a method for producing a Ti-MWW molecular sieve-containing catalyst, comprising the following steps:

[0071] (1) directing the powdered Ti-MWW molecular sieve, binder, pore-forming agent and fluoride to molding and calcination to obtain a molded product;

[0072] (2) crystallizing the molded product obtained in step (1) in the presence of an organic amine solution to obtain a catalyst precursor A;

[0073] (3) treating the catalyst precursor A obtained in step (2) with an acid solution and calcining to obtain the catalyst precursor B;

[0074] (4) treating the catalyst precursor B obtained in step (3) with an organic amine solution to obtain a catalyst.

[0075] The Ti-MWW molecular sieve powder preferably has a silicon-titanium molar ratio of 5 to 120 atomic amounts. The Ti-MWW molecular sieve powder can be a commercially available molecular sieve or can be manufactured according to the techniques described in the art.

[0076] Preferably, the binder is an amorphous binder and comprises a silicon source and at least one substance selected from the group consisting of a boron source and an aluminum source. Preferably, the amorphous binder comprises a silicon source and a boron source. More preferably, in terms of oxides, the silicon source, boron source, and aluminum source are present in a molar ratio of 1:x:y, where x=0-0.5, y=0-0.5, and x+y=0.02-1.Preferably, the silicon source is at least one substance selected from the group consisting of silica sol, sodium silicate, white carbon black, and ethyl orthosilicate; the boron source is at least one substance selected from the group consisting of boric acid, boron oxide, and borates; the aluminum source is at least one substance selected from the group consisting of aluminum oxide, aluminum hydroxide, sodium metaaluminate, aluminum nitrate, and aluminum sulfate. The binder is a commercially available binder or can be manufactured using methods described in the art. According to one embodiment, the binder can be manufactured by mixing components (such as, for example, a silicon source, a boron source, and an aluminum source).

[0077] Preferably, the pore-forming substance is at least one substance 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).

[0078] Preferably, the fluoride is at least one substance selected from the group consisting of sodium fluoride, potassium fluoride, and ammonium fluoride.

[0079] Preferably, in the step (1), the Ti-MWW molecular sieve powder, the binder, the pore-forming agent and the fluoride are used in a weight ratio of 1:(0.1-1.5):(0.01-0.1):(0.01-0.4).

[0080] Preferably, in step (1), before molding, the powdered Ti-MWW molecular sieve, binder, pore-forming agent, and fluoride are mixed, preferably in the presence of water. Optionally, in step (1), after mixing and molding, the product is dried. Preferably, drying is carried out at a temperature of 60-120°C for 1-24 hours.

[0081] Preferably, in step (1), calcination is carried out at a temperature of 450-650°C in an oxygen-containing atmosphere for 4-12 hours. The oxygen-containing atmosphere may be air or oxygen, and is preferably air.

[0082] Preferably, in step (2), the molded product obtained in step (1) is placed on the organic amine solution, but is not brought into contact with the organic amine solution.

[0083] Preferably, in step (2), the organic amine is at least one substance selected from the group consisting of piperidine and hexamethyleneimine. According to one embodiment, the organic amine solution has a concentration of 0.3-15 mol / L. Preferably, the molded product and the organic amine solution are used in a weight ratio of (0.1-10):1. According to one embodiment, the crystallization is carried out in a closed environment at a temperature of 130-190°C and autogenous pressure for 1-9 days.

[0084] Preferably, step (2) further comprises: after crystallization, subjecting the product to washing and drying. Preferably, washing is carried out with water. Drying is preferably carried out at a temperature of 60-120°C for 1-24 hours.

[0085] Preferably, step (2) does not involve calcination.

[0086] Preferably, step (3) comprises: bringing the catalyst precursor A obtained in step (2) and an acid solution into contact and performing a reaction. The acid solution is at least one substance selected from the group consisting of solutions of nitric acid, hydrochloric acid, sulfuric acid, formic acid, acetic acid and oxalic acid. The acid solution has a concentration of 0.3-12 mol / L. The catalyst precursor A and the acid solution are used in a weight ratio of 1:(10-80). Treatment with the acid solution is carried out at a temperature of 60-130°C for 4-48 hours.

[0087] Optionally, in step (3), after treatment with the acid solution, the product is washed and dried. Preferably, washing is carried out with water. Drying is preferably carried out at a temperature of 60-120°C for 1-24 hours.

[0088] Preferably, in step (3), calcination is carried out at a temperature of 450-650°C in an oxygen-containing atmosphere for 4-12 hours. The oxygen-containing atmosphere may be air or oxygen, and is preferably air.

[0089] Preferably, step (4) comprises: bringing the catalyst precursor B obtained in step (3) and the organic amine solution into contact and performing the reaction in the presence of fluoride. The fluoride is at least one substance selected from the group consisting of sodium fluoride, potassium fluoride and ammonium fluoride. The organic amine is at least one substance selected from the group consisting of piperidine and hexamethyleneimine. The organic amine solution has a concentration of 0.3-15 mol / L. The catalyst precursor B, the fluoride and the organic amine solution are used in a weight ratio of 1:(0.05-0.4):(2-20). The treatment with the organic amine solution is carried out at a temperature of 130-190°C for 4-48 hours.

[0090] Optionally, in step (4), after treatment with an organic amine solution, the product is washed and dried. Preferably, washing is carried out with water. Drying is preferably carried out at a temperature of 60-120°C for 1-24 hours.

[0091] Preferably, step (4) does not involve calcination.

[0092] According to a further embodiment of the present invention, a Ti-MWW molecular sieve-containing catalyst produced by the method described above is provided. The Ti-MWW molecular sieve-containing catalyst has all the characteristics of the Ti-MWW molecular sieve-containing catalyst according to the present invention, which are described above and which are not repeated hereinafter.

[0093] According to a further embodiment of the present invention, there is provided the use of a Ti-MWW molecular sieve-containing catalyst in the epoxidation of olefins.

[0094] The preferred method comprises the following steps: mixing olefins, an aqueous hydrogen peroxide solution, solvents, and alkaline nitrogen-containing materials to form a feed solution, then contacting the feed solution with a catalyst and performing a reaction. According to one embodiment, the reaction is carried out in a fixed-bed reactor.

[0095] Preferably, the olefins are liquefied olefins. The olefins are at least one substance selected from the group consisting of propylene, allyl chloride, butene, pentene, cyclopentene, hexene, and cyclohexene. The aqueous hydrogen peroxide solution has a concentration of 10-70 wt%. The solvent is at least one substance selected from the group consisting of methanol, acetonitrile, propionitrile, acetone, and tert-butyl alcohol. The alkaline nitrogen-containing material is at least one substance selected from the group consisting of piperidine and hexamethyleneimine.

[0096] Preferably, in the feed solution, olefins and hydrogen peroxide are present in a molar ratio of 1:0.3-1. Olefins are present in the feed solution in an amount of 1-50 wt.%; solvents are present in the feed solution in an amount of 30-90 wt.%; and alkaline nitrogen-containing materials are present in the feed solution in an amount of 1-50 ppm.

[0097] The reaction is preferably carried out under the following conditions: the flow rate of the catalyst per unit mass of the feed solution is 3-30 ml⋅g кат . -1 ⋅h -1 , the temperature is 30-100°C, and the pressure is 0.1-4 MPa.

[0098] Examples

[0099] The features and advantages of the present invention become apparent from the following examples. These examples are intended to illustrate, but are not intended to limit, the present invention in any way.

[0100] Research Methods

[0101] According to the present invention, for example, in the following examples and comparative examples, the type, state, structure and morphology of titanium fragments of the molecular sieve-containing catalyst were determined, respectively, by ultraviolet Raman spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction and scanning electron microscopy. The molar ratio of silicon to titanium, the molar ratio of boron to silicon, and the molar ratio of aluminum to silicon of the molecular sieve-containing catalyst were determined by inductively coupled plasma atomic emission spectroscopy. The micropore volume, mesopore volume and macropore volume of the molecular sieve-containing catalyst were determined, respectively, by nitrogen adsorption-desorption and mercury intrusion porosimetry. The results were used to calculate the proportion of the micropore volume relative to the total pore volume as follows.That is, the proportion of micropore volume to total pore volume is the result of dividing the micropore volume by the sum of the micropore volume, mesopore volume, and macropore volume. The mechanical strength of the molecular sieve-containing catalyst was determined using a strength measuring device.

[0102] According to the present invention, the ultraviolet Raman spectroscopy study included: performing the study using the proprietary UV Raman-100 ultraviolet Raman spectrometer, wherein the excitation wavelength was 244 nm, the laser power was 5.0 mW per sample, and the spectral resolution was 4 cm -1 , and as a result, the ultraviolet Raman spectrum of the molecular sieve-containing catalyst was obtained. The peak intensity was calculated by subtracting the baseline value from the peak value.

[0103] According to the present invention, the X-ray photoelectron spectroscopy study included: performing the study using an AXIS Ultra DLD X-ray photoelectron spectrometer with an Al Kα (1486.6 eV) radiation source, while the sample chamber was evacuated to a pressure of 10 -9 Torr, and calibration was performed using the C 1s peak at 284.8 eV. OriginPro 9 software was used to approximate the peaks.

[0104] According to the present invention, the X-ray diffraction study included: analyzing a sample using a Rigaku UlTima IV X-ray powder diffractometer with a Cu Kα (λ=1.54 Ǻ) radiation source and a nickel filter, the 2θ scanning range was 2-50°, the working voltage was 40 kV, the current was 40 mA, and the scanning speed was 10° / min.

[0105] According to the present invention, the scanning electron microscopy examination included: performing the examination using a Hitachi S-4800 electron microscope with an accelerating voltage of 3 kV.

[0106] According to the present invention, an inductively coupled plasma atomic emission spectroscopy study included: analyzing a sample using a Varian-2000 analyzer to determine the molar ratio of silicon to titanium, the molar ratio of boron to silicon, and the molar ratio of aluminum to silicon in the sample, wherein the sample was dissolved in a hydrofluoric acid solution before the study.

[0107] According to the present invention, a nitrogen adsorption-desorption test included: determining the nitrogen adsorption-desorption isotherm of a sample using an American Micromeritics ASAP2460 micropore volume measuring instrument, and the test was carried out at a temperature of 77 K, and the sample was subjected to a vacuum pre-treatment at a temperature of 573 K for 6 hours before the test.

[0108] According to the present invention, a mercury intrusion porosimetry study included: performing a study using a high-performance fully automated mercury intrusion porosimeter AutoPore IV 9505.

[0109] According to the present invention, the mechanical strength test included: conducting a test using a DL-2 particle strength measuring instrument. Specifically, the catalyst particle size in the direction of the applied force was determined, and then the external force required to crush the catalyst into powder was determined. The mechanical strength of the catalyst was calculated by dividing the external force by the particle size.

[0110] According to the present invention, for example, in the following examples and comparative examples, the catalytic performance of the molecular sieve-containing catalyst was described by parameters such as the proportion of residual hydrogen peroxide, the conversion rate of hydrogen peroxide, the selectivity to the main products (such as epoxides) and the selectivity to the by-products (such as glycols and alcohol ethers), the ratio of the main products and the by-products, and the stability retention period of the catalyst.

[0111] According to the present invention, a feed solution sample was obtained from the inlet of a tubular reactor, and a reaction liquid sample was obtained from the outlet of the tubular reactor. The reaction liquid sample can be obtained at any stage of the reaction, for example, immediately after the reaction liquid exits the outlet of the tubular reactor, during the reaction, or at the end of the reaction. The feed solution sample and the reaction liquid sample were analyzed for hydrogen peroxide concentration by titration with a cerium sulfate solution. The results were used to calculate the proportion of residual hydrogen peroxide and the hydrogen peroxide conversion rate according to the following formulas.

[0112] Residual hydrogen peroxide ratio (%) = hydrogen peroxide concentration in reaction liquid (mol / L) / hydrogen peroxide concentration in feed solution (mol / L) × 100%

[0113] Hydrogen peroxide conversion rate (%) = 1 - residual hydrogen peroxide ratio (%)

[0114] According to the present invention, a sample of the feed solution and a sample of the reaction liquid were analyzed for their respective compositions using gas chromatography. The results were used to determine the amount of olefins converted during the reaction and the amount of epoxide products formed during the reaction. As a result, the selectivity for the main epoxide products and the ratio of the main epoxide products to the byproducts glycols and alcohol ethers were calculated.

[0115] The molar amount of olefins converted during the reaction = the molar amount of olefins in the feed solution sample - the molar amount of olefins in the reaction liquid sample.

[0116] Epoxide selectivity (%) = molar amount of epoxide products in the reaction liquid sample / molar amount of olefins converted during the reaction × 100%.

[0117] The ratio of main products to by-products = molar amount of epoxy products in the reaction liquid sample / (molar amount of olefins converted during the reaction - molar amount of epoxy products in the reaction liquid sample) × 100%.

[0118] According to the present invention, the stability retention period of the catalyst was the period of time from the start of the reaction to the time when the proportion of residual hydrogen peroxide in the reaction liquid sample was 2%.

[0119] In the examples and comparative examples, the Ti-MWW powder molecular sieve was RT-03B molecular sieve commercially available from Zhejiang TWRD New Materials Co., Ltd., in which the titanium fragments were only framework tetracoordinate titanium fragments. The synthesized Ti-MWW powder molecular sieve, which was prepared according to the literature description (Journal of Physical Chemistry B, 2001, 105, 2897), contained only extraframework hexacoordinate titanium fragments.

[0120] Example 1

[0121] (1) 90g of Ti-MWW molecular sieve powder having a silicon-to-titanium molar ratio of 20, 90g of amorphous binder (this amorphous binder contained 75g of silica sol containing silica in a weight fraction of 40% and 15g of boric acid), 3g of sesbania powder and 9g of sodium fluoride were mixed by mechanical stirring, and then 80g of water was added to the resulting mixture. After mixing and stirring for 4 hours, a solid mixture was obtained, which was sent to molding by mechanical extrusion, dried at 100°C for 8 hours, and then calcined at 550°C for 6 hours to obtain a cylindrical molded product.

[0122] (2) 90g of the cylindrical molded product obtained in step (1) was placed onto 60g of a 3mol / L piperidine solution without contact between them to achieve crystallization at 170°C for 2 days in a closed environment. The product was washed with water and dried at 100°C for 8 hours to obtain cylindrical catalyst precursor A.

[0123] (3) 60 g of the cylindrical catalyst precursor A obtained in step (2) and a 2 mol / L nitric acid solution were mixed at a weight ratio of 1:50, and then 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 the cylindrical catalyst precursor B.

[0124] (4) 40 g of the cylindrical catalyst precursor B obtained in step (3), ammonium fluoride and a 3 mol / L piperidine solution were mixed at a weight ratio of 1:0.1:10, and then 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-containing catalyst, which was given the code name S1.

[0125] Catalyst S1 was sent for studies in accordance with the above description.

[0126] The X-ray photoelectron spectrum of catalyst S1, which is illustrated in Fig. 1, shows peaks at 458.9, 460.3, 464.8, and 465.9 eV. Among them, the peaks at 460.3 and 465.9 eV corresponded to the framework tetracoordinated titanium fragments, and the peaks at 458.9 and 464.8 eV corresponded to the modified extraframework hexacoordinated titanium fragments.

[0127] The ultraviolet Raman spectrum of catalyst S1, which is illustrated in Fig. 2, shows peaks at 343, 484, 699 and 1097 cm -1 . Peak intensity at 699 cm -1 represented a 5.3-fold peak intensity at 343 cm -1 , and the peak intensity at 1097 cm -1 represented a 5.1-fold peak intensity at 343 cm - 1. Among them, the peak is at 343 cm -1 corresponded to the MWW structure, peaks at 484 and 1097 cm -1 corresponded to framework tetracoordinated titanium fragments, and the peak at 699 cm-1 corresponded to modified extraframework hexacoordinated titanium fragments.

[0128] The X-ray diffraction pattern of catalyst S1 is illustrated in Fig. 3. This diffraction pattern contained intense diffraction peaks at 2θ angles of 3.3°, 6.6°, 7.2°, 7.9°, 9.7° and 26.1°, and the intensity of the diffraction peak at 2θ angle of 7.2° reached 5300, showing that catalyst S1 had an MWW structure and a high degree of crystallinity.

[0129] The scanning electron microscope image of catalyst S1 is illustrated in Fig. 4. Catalyst S1 showed a platelet morphology in which no nanoparticles were observed, which indicated that catalyst S1 existed only in the MWW structure.

[0130] Catalyst S1 was characterized by a silicon-to-titanium molar ratio of 35 and a boron-to-silicon molar ratio of 0.015.

[0131] Catalyst S1 was characterized by a micropore volume of 0.09 cm 3 / g, the proportion of micropore volume in relation to the total pore volume, amounting to 3.6%, and mechanical strength, amounting to 66 N / cm.

[0132] Example 2

[0133] (1) 90g of Ti-MWW molecular sieve powder having a silicon-to-titanium molar ratio of 5, 90g of amorphous binder (this amorphous binder contained 75g of silica sol containing silica in a weight fraction of 40% and 15g of boric acid), 3g of starch and 0.9g of potassium fluoride were mixed by mechanical stirring, and then 80g of water was added to the resulting mixture. After mixing and stirring for 4 hours, a solid mixture was obtained, which was sent to molding by mechanical extrusion, dried at 100°C for 8 hours, and then calcined at 550°C for 6 hours to obtain a cylindrical molded product.

[0134] (2) 90g of the cylindrical molded product obtained in step (1) was placed onto 60g of a 3mol / L piperidine solution without contact between them to achieve crystallization at 170°C for 2 days in a closed environment. The product was washed with water and dried at 100°C for 8 hours to obtain cylindrical catalyst precursor A.

[0135] (3) 60 g of the cylindrical catalyst precursor A obtained in step (2) and a 2 mol / L nitric acid solution were mixed at a solid-to-liquid mass ratio of 1:50, and then 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 the cylindrical catalyst precursor B.

[0136] (4) 40 g of the cylindrical catalyst precursor B obtained in step (3), ammonium fluoride and a 3 mol / L piperidine solution were mixed at a weight ratio of 1:0.1:10, and then 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-containing catalyst, which was given the designation S2.

[0137] Catalyst S2 was sent for studies in accordance with the above description.

[0138] The X-ray photoelectron spectrum of catalyst S2 showed peaks at 459.1, 460.1, 465.0 and 465.7 eV.

[0139] The ultraviolet Raman spectrum of catalyst S2 showed peaks at 341, 487, 702 and 1094 cm -1 . Peak intensity at 702 cm -1 represented a 10-fold intensity of the peak at 341 cm -1 , and the peak intensity at 1094 cm-1 represented a 10-fold intensity of the peak at 341 cm -1 .

[0140] The X-ray diffraction pattern and the scanning electron microscope image of catalyst S2 were similar to those in Fig. 3 and Fig. 4, respectively.

[0141] Catalyst S2 had a silicon-to-titanium molar ratio of 10 and a boron-to-silicon molar ratio of 0.005.

[0142] Catalyst S2 was characterized by a micropore volume of 0.05 cm 3 / g, the proportion of micropore volume in relation to the total pore volume, amounting to 1.7%, and mechanical strength, amounting to 40 N / cm.

[0143] Example 3

[0144] (1) 90g of Ti-MWW molecular sieve powder having a silicon-titanium molar ratio of 120, 90g of amorphous binder (this amorphous binder contained 75g of silica sol containing silica in a weight fraction of 40% and 15g of boric acid), 9g of cellulose and 36g of ammonium fluoride were mixed by mechanical stirring, and then 80g of water was added to the resulting mixture. After mixing and stirring for 4 hours, a solid mixture was obtained, which was sent to molding by mechanical extrusion, dried at 100°C for 8 hours, and then calcined at 550°C for 6 hours to obtain a cylindrical molded product.

[0145] (2) 90g of the cylindrical molded product obtained in step (1) was placed onto 60g of a 3 mol / L piperidine solution without contact between them to achieve crystallization at 170°C for 2 days in a closed environment. The product was washed with water and dried at 100°C for 8 hours to obtain cylindrical catalyst precursor A.

[0146] (3) 60 g of cylindrical catalyst precursor A obtained in step

[0147] (2) and a 2 mol / L nitric acid solution were mixed at a weight ratio of 1:50, and then 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.

[0148] (4) 40 g of the cylindrical catalyst precursor B obtained in step (3), ammonium fluoride and a 3 mol / L piperidine solution were mixed at a weight ratio of 1:0.1:10, and then 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-containing catalyst, which was given the code name S3.

[0149] Catalyst S3 was sent for studies in accordance with the above description.

[0150] The X-ray photoelectron spectrum of catalyst S3 showed peaks at 458.7, 460.4, 464.6 and 466.0 eV.

[0151] The ultraviolet Raman spectrum of catalyst S3 showed peaks at 345, 482, 696 and 1099 cm -1 . Peak intensity at 696 cm -1 represented 0.5 times the intensity of the peak at 345 cm -1 , and the peak intensity at 1099 cm-1 represented 0.5 times the intensity of the peak at 345 cm -1 .

[0152] The X-ray diffraction pattern and the scanning electron microscope image of catalyst S3 were similar to those in Fig. 3 and Fig. 4, respectively.

[0153] Catalyst S3 had a silicon-to-titanium molar ratio of 200 and a boron-to-silicon molar ratio of 0.03.

[0154] Catalyst S3 was characterized by a micropore volume of 0.07 cm 3 / g, the proportion of micropore volume in relation to the total pore volume, amounting to 2.3%, and mechanical strength, amounting to 80 N / cm.

[0155] Example 4

[0156] (1) 90g of Ti-MWW molecular sieve powder having a silicon-titanium molar ratio of 20, 9g of amorphous binder (this amorphous binder contained 8g of silica sol containing silica in a weight fraction of 25% and 1g of sodium tetraborate), 3g of sesbania powder and 9g of sodium fluoride were mixed by mechanical stirring, and then 120g of water were added to the resulting mixture. After mixing and stirring for 4 hours, a solid mixture was obtained, which was sent to molding by mechanical extrusion, dried at 100°C for 8 hours, and then calcined at 450°C for 12 hours to obtain a cylindrical molded product.

[0157] (2) 90g of the cylindrical molded product obtained in step (1) was placed onto 60g of a 3mol / L piperidine solution without contact between them to achieve crystallization at 170°C for 2 days in a closed environment. The product was washed with water and dried at 100°C for 8 hours to obtain cylindrical catalyst precursor A.

[0158] (3) 60 g of the cylindrical catalyst precursor A obtained in step (2) and a 2 mol / L nitric acid solution were mixed at a weight ratio of 1:50, and then 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 the cylindrical catalyst precursor B.

[0159] (4) 40 g of the cylindrical catalyst precursor B obtained in step (3), ammonium fluoride and a 3 mol / L piperidine solution were mixed at a weight ratio of 1:0.1:10, and then 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-containing catalyst, which was given the designation S4.

[0160] Catalyst S4 was sent for studies in accordance with the above description.

[0161] The X-ray photoelectron spectrum of catalyst S4 showed peaks at 458.7, 460.5, 464.6 and 466.1 eV.

[0162] The ultraviolet Raman spectrum of catalyst S4 showed peaks at 347, 480, 695 and 1101 cm -1 . Peak intensity at 695 cm -1 represented an 8.2-fold peak intensity at 347 cm -1 , and the peak intensity at 1101 cm-1 represented a 7.8-fold peak intensity at 347 cm -1 .

[0163] The X-ray diffraction pattern and the scanning electron microscope image of catalyst S4 were similar to those in Fig. 3 and Fig. 4, respectively.

[0164] Catalyst S4 was characterized by a silicon-to-titanium molar ratio of 25 and a boron-to-silicon molar ratio of 0.003.

[0165] Catalyst S4 was characterized by a micropore volume of 0.06 cm 3 / g, the proportion of micropore volume in relation to the total pore volume, which is 2%, and the mechanical strength, which is 30 N / cm.

[0166] Example 5

[0167] (1) 90g of Ti-MWW molecular sieve powder having a silicon-to-titanium molar ratio of 20, 90g of amorphous binder (this amorphous binder contained 30g of white carbon, 30g of boric acid, and 30g of aluminum hydroxide), 3g of sesbania powder, and 9g of sodium fluoride were mixed by mechanical stirring, and then 120g of water was added to the resulting mixture. After mixing and stirring for 4 hours, a solid mixture was obtained, which was sent to molding by mechanical extrusion, dried at 100°C for 8 hours, and then calcined at 650°C for 4 hours to obtain a cylindrical molded product.

[0168] (2) 90g of the cylindrical molded product obtained in step (1) was placed onto 60g of a 3 mol / L piperidine solution without contact between them to achieve crystallization at 170°C for 2 days in a closed environment. The product was washed with water and dried at 100°C for 8 hours to obtain cylindrical catalyst precursor A.

[0169] (3) 60 g of the cylindrical catalyst precursor A obtained in step (2) and a 2 mol / L nitric acid solution were mixed at a weight ratio of 1:50, and then 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 the cylindrical catalyst precursor B.

[0170] (4) 40 g of the cylindrical catalyst precursor B obtained in step (3), ammonium fluoride and a 3 mol / L piperidine solution were mixed at a weight ratio of 1:0.1:10, and then 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-containing catalyst, which was given the code name S5.

[0171] Catalyst S5 was sent for studies in accordance with the above description.

[0172] The X-ray photoelectron spectrum of catalyst S5 showed peaks at 459.0, 460.2, 464.9 and 465.8 eV.

[0173] The ultraviolet Raman spectrum of catalyst S5 showed peaks at 341, 486, 701 and 1095 cm -1 . Peak intensity at 701 cm -1 represented a 2.9-fold peak intensity at 341 cm -1 , and the peak intensity at 1095 cm-1 represented a 2.6-fold peak intensity at 341 cm -1 .

[0174] The X-ray diffraction pattern and the scanning electron microscope image of catalyst S5 were similar to those in Fig. 3 and Fig. 4, respectively.

[0175] Catalyst S5 was characterized by a silicon-titanium molar ratio of 60, a boron-silicon molar ratio of 0.1, and an aluminum-silicon molar ratio of 0.1.

[0176] Catalyst S5 was characterized by a micropore volume of 0.1 cm 3 / g, the proportion of micropore volume in relation to the total pore volume, amounting to 4%, and mechanical strength, amounting to 77 N / cm.

[0177] Example 6

[0178] (1) 90g of Ti-MWW molecular sieve powder having a silicon-to-titanium molar ratio of 20, 90g of amorphous binder (this amorphous binder contained 75g of silica sol containing silica in a weight fraction of 40% and 15g of aluminum hydroxide), 3g of sesbania powder and 9g of sodium fluoride were mixed by mechanical stirring, and then 80g of water was added to the resulting mixture. After mixing and stirring for 4 hours, a solid mixture was obtained, which was sent to molding by mechanical extrusion, dried at 100°C for 8 hours, and then calcined at 550°C for 6 hours to obtain a cylindrical molded product.

[0179] (2) 90g of the cylindrical molded product obtained in step (1) was placed onto 60g of a 3mol / L piperidine solution without contact between them to achieve crystallization at 170°C for 2 days in a closed environment. The product was washed with water and dried at 100°C for 8 hours to obtain cylindrical catalyst precursor A.

[0180] (3) 60 g of the cylindrical catalyst precursor A obtained in step (2) and a 2 mol / L nitric acid solution were mixed at a weight ratio of 1:50, and then 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 the cylindrical catalyst precursor B.

[0181] (4) 40 g of the cylindrical catalyst precursor B obtained in step (3), ammonium fluoride and a 3 mol / L piperidine solution were mixed at a weight ratio of 1:0.1:10, and then 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-containing catalyst, which was given the code name S6.

[0182] Catalyst S6 was sent for studies in accordance with the above description.

[0183] The X-ray photoelectron spectrum of catalyst S6 showed peaks at 459.1, 460.1, 465.0 and 465.7 eV.

[0184] The ultraviolet Raman spectrum of catalyst S6 showed peaks at 339, 488, 703 and 1093 cm -1 . Peak intensity at 703 cm -1 represented a 4.9-fold peak intensity at 339 cm -1 , and the peak intensity at 1093 cm-1 represented a 5.2-fold peak intensity at 339 cm -1 .

[0185] The X-ray diffraction pattern and the scanning electron microscope image of catalyst S6 were similar to those in Fig. 3 and Fig. 4, respectively.

[0186] Catalyst S6 had a silicon-to-titanium molar ratio of 37 and an aluminum-to-silicon molar ratio of 0.05.

[0187] Catalyst S6 was characterized by a micropore volume of 0.12 cm 3 / g, the proportion of micropore volume in relation to the total pore volume, amounting to 6%, and mechanical strength, amounting to 90 N / cm.

[0188] Example 7

[0189] (1) 90g of Ti-MWW molecular sieve powder having a silicon-to-titanium molar ratio of 20, 90g of amorphous binder (this amorphous binder contained 75g of silica sol containing silica in a weight fraction of 40% and 15g of boric acid), 3g of sesbania powder and 9g of sodium fluoride were mixed by mechanical stirring, and then 80g of water was added to the resulting mixture. After mixing and stirring for 4 hours, a solid mixture was obtained, which was sent to molding by spheronization, drying at 100°C for 8 hours, and then calcining at 550°C for 6 hours to obtain a spherical molded product.

[0190] (2) 90 g of the spherical molded product obtained in step (1) was placed onto 60 g of a 3 mol / L piperidine solution without contact between them to achieve crystallization at 170°C for 2 days in a closed environment. The product was washed with water and dried at 100°C for 8 hours to obtain spherical catalyst precursor A.

[0191] (3) 60 g of the spherical catalyst precursor A obtained in step (2) and a 2 mol / L nitric acid solution were mixed at a weight ratio of 1:50, and then 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 the spherical catalyst precursor B.

[0192] (4) 40 g of the spherical catalyst precursor B obtained in step (3), ammonium fluoride and a 3 mol / L piperidine solution were mixed at a weight ratio of 1:0.1:10, and then 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-containing catalyst, which was given the code name S7.

[0193] Catalyst S7 was sent for studies in accordance with the above description.

[0194] The X-ray photoelectron spectrum of catalyst S7 showed peaks at 458.9, 460.3, 464.8 and 465.9 eV.

[0195] The ultraviolet Raman spectrum of catalyst S7 showed peaks at 343, 484, 699 and 1097 cm -1 . Peak intensity at 699 cm -1 represented a 5.3-fold peak intensity at 343 cm -1 , and the peak intensity at 1097 cm-1 represented a 5.2-fold peak intensity at 343 cm -1 .

[0196] The X-ray diffraction pattern and the scanning electron microscope image of catalyst S7 were similar to those in Fig. 3 and Fig. 4, respectively.

[0197] Catalyst S7 was characterized by a silicon-to-titanium molar ratio of 34 and a boron-to-silicon molar ratio of 0.014.

[0198] Catalyst S7 was characterized by a micropore volume of 0.09 cm 3 / g, the proportion of micropore volume in relation to the total pore volume, amounting to 3.6%, and mechanical strength, amounting to 80 N / cm.

[0199] Example 8

[0200] (1) 90g of Ti-MWW molecular sieve powder having a silicon-titanium molar ratio of 20, 90g of amorphous binder (this amorphous binder contained 75g of silica sol containing silica in a weight fraction of 40% and 15g of boric acid), 3g of sesbania powder and 9g of sodium fluoride were mixed by mechanical stirring, and then 80g of water was added to the resulting mixture. After mixing and stirring for 4 hours, a solid mixture was obtained, which was sent to molding by mechanical extrusion, dried at 100°C for 8 hours, and then calcined at 550°C for 6 hours to obtain a cylindrical molded product.

[0201] (2) 90 g of the cylindrical molded product obtained in step (1) was placed onto 900 g of a 0.3 mol / L piperidine solution without contact between them to achieve crystallization at 170°C for 2 days in a closed environment. The product was washed with water and dried at 100°C for 8 hours to obtain cylindrical catalyst precursor A.

[0202] (3) 60 g of the cylindrical catalyst precursor A obtained in step (2) and a 2 mol / L nitric acid solution were mixed at a weight ratio of 1:50, and then 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 the cylindrical catalyst precursor B.

[0203] (4) 40 g of the cylindrical catalyst precursor B obtained in step (3), ammonium fluoride and a 3 mol / L piperidine solution were mixed at a weight ratio of 1:0.1:10, and then 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-containing catalyst, which was given the code name S8.

[0204] Catalyst S8 was sent for studies in accordance with the above description.

[0205] The X-ray photoelectron spectrum of S8 catalyst showed peaks at 459.0, 460.2, 464.9 and 465.8 eV.

[0206] The ultraviolet Raman spectrum of the S8 catalyst showed peaks at 341, 486, 701 and 1095 cm -1 . Peak intensity at 701 cm -1 represented a 4.8-fold peak intensity at 341 cm -1 , and the peak intensity at 1095 cm-1 represented a 5.9-fold peak intensity at 341 cm -1 .

[0207] The X-ray diffraction pattern and the scanning electron microscope image of catalyst S8 were similar to those in Fig. 3 and Fig. 4, respectively.

[0208] Catalyst S8 was characterized by a silicon-to-titanium molar ratio of 32 and a boron-to-silicon molar ratio of 0.017.

[0209] Catalyst S8 was characterized by a micropore volume of 0.07 cm 3 / g, the proportion of micropore volume in relation to the total pore volume, amounting to 2.3%, and mechanical strength, amounting to 56 N / cm.

[0210] Example 9

[0211] (1) 90g of Ti-MWW molecular sieve powder having a silicon-titanium molar ratio of 20, 90g of amorphous binder (this amorphous binder contained 75g of silica sol containing silica in a weight fraction of 40% and 15g of boric acid), 3g of sesbania powder and 9g of sodium fluoride were mixed by mechanical stirring, and then 80g of water was added to the resulting mixture. After mixing and stirring for 4 hours, a solid mixture was obtained, which was sent to molding by mechanical extrusion, dried at 100°C for 8 hours, and then calcined at 550°C for 6 hours to obtain a cylindrical molded product.

[0212] (2) 90 g of the cylindrical molded product obtained in step (1) was placed onto 9 g of a 15 mol / L piperidine solution without contact between them to achieve crystallization at 170°C for 2 days in a closed environment. The product was washed with water and dried at 100°C for 8 hours to obtain cylindrical catalyst precursor A.

[0213] (3) 60 g of the cylindrical catalyst precursor A obtained in step (2) and a 2 mol / L nitric acid solution were mixed at a weight ratio of 1:50, and then 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 the cylindrical catalyst precursor B.

[0214] (4) 40 g of the cylindrical catalyst precursor B obtained in step (3), ammonium fluoride and a 3 mol / L piperidine solution were mixed at a weight ratio of 1:0.1:10, and then 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-containing catalyst, which was given the code name S9.

[0215] Catalyst S9 was sent for studies in accordance with the above description.

[0216] The X-ray photoelectron spectrum of catalyst S9 showed peaks at 458.9, 460.4, 464.8 and 466.0 eV.

[0217] The ultraviolet Raman spectrum of catalyst S9 showed peaks at 345, 483, 698 and 1099 cm -1 . Peak intensity at 698 cm -1 represented a 5.7-fold peak intensity at 345 cm -1 , and the peak intensity at 1099 cm-1 represented a 4.9-fold peak intensity at 345 cm -1 .

[0218] The X-ray diffraction pattern and the scanning electron microscope image of catalyst S9 were similar to those in Fig. 3 and Fig. 4, respectively.

[0219] Catalyst S9 had a silicon-to-titanium molar ratio of 34 and a boron-to-silicon molar ratio of 0.016.

[0220] Catalyst S9 was characterized by a micropore volume of 0.08 cm 3 / g, the proportion of micropore volume in relation to the total pore volume, amounting to 3.2%, and mechanical strength, amounting to 64 N / cm.

[0221] Example 10

[0222] (1) 90g of Ti-MWW molecular sieve powder having a silicon-titanium molar ratio of 20, 90g of amorphous binder (this amorphous binder contained 75g of silica sol containing silica in a weight fraction of 40% and 15g of boric acid), 3g of sesbania powder and 9g of sodium fluoride were mixed by mechanical stirring, and then 80g of water was added to the resulting mixture. After mixing and stirring for 4 hours, a solid mixture was obtained, which was sent to molding by mechanical extrusion, dried at 100°C for 8 hours, and then calcined at 550°C for 6 hours to obtain a cylindrical molded product.

[0223] (2) 90 g of the cylindrical molded product obtained in step (1) was placed onto 60 g of a 3 mol / L hexamethyleneimine solution without contact between them to achieve crystallization at 130°C for 9 days in a closed environment. The product was washed with water and dried at 100°C for 8 hours to obtain cylindrical catalyst precursor A.

[0224] (3) 60 g of the cylindrical catalyst precursor A obtained in step (2) and a 2 mol / L nitric acid solution were mixed at a weight ratio of 1:50, and then 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 the cylindrical catalyst precursor B.

[0225] (4) 40 g of the cylindrical catalyst precursor B obtained in step (3), ammonium fluoride and a 3 mol / L piperidine solution were mixed at a weight ratio of 1:0.1:10, and then 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-containing catalyst, which was given the code name S10.

[0226] Catalyst S10 was sent for studies in accordance with the above description.

[0227] The X-ray photoelectron spectrum of the S10 catalyst showed peaks at 459.0, 460.2, 464.9 and 465.8 eV.

[0228] The ultraviolet Raman spectrum of the S10 catalyst showed peaks at 341, 486, 701 and 1095 cm -1 . The intensity of the peak at 701 cm- 1 represented a 4.5-fold peak intensity at 341 cm -1, and the peak intensity at 1095 cm -1 represented a 4.9-fold peak intensity at 341 cm -1 .

[0229] The X-ray diffraction pattern and the scanning electron microscope image of the S10 catalyst were similar to those in Fig. 3 and Fig. 4, respectively.

[0230] Catalyst S10 was characterized by a silicon-to-titanium molar ratio of 42 and a boron-to-silicon molar ratio of 0.02.

[0231] Catalyst S10 was characterized by a micropore volume of 0.06 cm 3 / g, the proportion of micropore volume in relation to the total pore volume, amounting to 2%, and mechanical strength, amounting to 45 N / cm.

[0232] Example 11

[0233] (1) 90g of Ti-MWW molecular sieve powder having a silicon-to-titanium molar ratio of 20, 90g of amorphous binder (this amorphous binder contained 75g of silica sol containing silica in a weight fraction of 40% and 15g of boric acid), 3g of sesbania powder and 9g of sodium fluoride were mixed by mechanical stirring, and then 80g of water was added to the resulting mixture. After mixing and stirring for 4 hours, a solid mixture was obtained, which was sent to molding by mechanical extrusion, dried at 100°C for 8 hours, and then calcined at 550°C for 6 hours to obtain a cylindrical molded product.

[0234] (2) 90 g of the cylindrical molded product obtained in step (1) was placed onto 60 g of a 3 mol / L hexamethyleneimine solution without contact to achieve crystallization at 190°C for 1 day in a closed environment. The product was washed with water and dried at 100°C for 8 hours to obtain cylindrical catalyst precursor A.

[0235] (3) 60 g of the cylindrical catalyst precursor A obtained in step (2) and a 2 mol / L nitric acid solution were mixed at a weight ratio of 1:50, and then 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 the cylindrical catalyst precursor B.

[0236] (4) 40 g of the cylindrical catalyst precursor B obtained in step (3), ammonium fluoride and a 3 mol / L piperidine solution were mixed at a weight ratio of 1:0.1:10, and then 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-containing catalyst, which was given the code name S11.

[0237] Catalyst S11 was sent for studies in accordance with the above description.

[0238] The X-ray photoelectron spectrum of catalyst S11 showed peaks at 458.9, 460.4, 464.8 and 466.0 eV.

[0239] The ultraviolet Raman spectrum of catalyst S11 showed peaks at 345, 482, 698 and 1099 cm -1 . Peak intensity at 698 cm -1 represented a 6-fold peak intensity at 345 cm -1, and the peak intensity at 1099 cm -1 represented a 5-fold peak intensity at 345 cm -1 .

[0240] The X-ray diffraction pattern and the scanning electron microscope image of catalyst S11 were similar to those in Fig. 3 and Fig. 4, respectively.

[0241] Catalyst S11 was characterized by a silicon-titanium molar ratio of 30 and a boron-silicon molar ratio of 0.01.

[0242] Catalyst S11 was characterized by a micropore volume of 0.07 cm 3 / g, the proportion of micropore volume in relation to the total pore volume, amounting to 2.3%, and mechanical strength, amounting to 69 N / cm.

[0243] Example 12

[0244] (1) 90g of Ti-MWW molecular sieve powder having a silicon-to-titanium molar ratio of 20, 90g of amorphous binder (this amorphous binder contained 75g of silica sol containing silica in a weight fraction of 40% and 15g of boric acid), 3g of sesbania powder and 9g of sodium fluoride were mixed by mechanical stirring, and then 80g of water was added to the resulting mixture. After mixing and stirring for 4 hours, a solid mixture was obtained, which was sent to molding by mechanical extrusion, dried at 100°C for 8 hours, and then calcined at 550°C for 6 hours to obtain a cylindrical molded product.

[0245] (2) 90g of the cylindrical molded product obtained in step (1) was placed onto 60g of a 3mol / L piperidine solution without contact between them to achieve crystallization at 170°C for 2 days in a closed environment. The product was washed with water and dried at 100°C for 8 hours to obtain cylindrical catalyst precursor A.

[0246] (3) 60 g of the cylindrical catalyst precursor A obtained in step (2) and a 12 mol / L hydrochloric acid solution were mixed at a weight ratio of 1:10, and then 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 the cylindrical catalyst precursor B.

[0247] (4) 40 g of the cylindrical catalyst precursor B obtained in step (3), ammonium fluoride and a 3 mol / L piperidine solution were mixed at a weight ratio of 1:0.1:10, and then 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-containing catalyst, which was given the code name S12.

[0248] Catalyst S12 was sent for studies in accordance with the above description.

[0249] The X-ray photoelectron spectrum of catalyst S12 showed peaks at 458.9, 460.5, 464.8 and 466.1 eV.

[0250] The ultraviolet Raman spectrum of catalyst S12 showed peaks at 344, 481, 698 and 1100 cm -1 . Peak intensity at 698 cm -1 represented a 3.3-fold peak intensity at 344 cm -1, and the peak intensity at 1100 cm -1 represented a 2.4-fold peak intensity at 344 cm -1 .

[0251] The X-ray diffraction pattern and the scanning electron microscope image of catalyst S12 were similar to those in Fig. 3 and Fig. 4, respectively.

[0252] Catalyst S12 had a silicon-to-titanium molar ratio of 57 and a boron-to-silicon molar ratio of 0.004.

[0253] Catalyst S12 was characterized by a micropore volume of 0.1 cm 3 / g, the proportion of micropore volume in relation to the total pore volume, amounting to 4%, and mechanical strength, amounting to 48 N / cm.

[0254] Example 13

[0255] (1) 90g of Ti-MWW molecular sieve powder having a silicon-to-titanium molar ratio of 20, 90g of amorphous binder (this amorphous binder contained 75g of silica sol containing silica in a weight fraction of 40% and 15g of boric acid), 3g of sesbania powder and 9g of sodium fluoride were mixed by mechanical stirring, and then 80g of water was added to the resulting mixture. After mixing and stirring for 4 hours, a solid mixture was obtained, which was sent to molding by mechanical extrusion, dried at 100°C for 8 hours, and then calcined at 550°C for 6 hours to obtain a cylindrical molded product.

[0256] (2) 90 g of the cylindrical molded product obtained in step (1) was placed onto 60 g of a 3 mol / L piperidine solution without contact between them to achieve crystallization at 170°C for 2 days in a closed environment. The product was washed with water and dried at 100°C for 8 hours to obtain cylindrical catalyst precursor A.

[0257] (3) 60 g of the cylindrical catalyst precursor A obtained in step (2) and a 0.3 mol / L oxalic acid solution were mixed at a weight ratio of 1:80, and then 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 the cylindrical catalyst precursor B.

[0258] (4) 40 g of the cylindrical catalyst precursor B obtained in step (3), ammonium fluoride and a 3 mol / L piperidine solution were mixed at a weight ratio of 1:0.1:10, and then 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-containing catalyst, which was given the code name S13.

[0259] Catalyst S13 was sent for studies in accordance with the above description.

[0260] The X-ray photoelectron spectrum of catalyst S13 showed peaks at 459.1, 460.1, 465.0 and 465.7 eV.

[0261] The ultraviolet Raman spectrum of catalyst S13 showed peaks at 341, 488, 702 and 1093 cm -1 . Peak intensity at 702 cm -1 represented a 5.9-fold peak intensity at 341 cm -1, and the peak intensity at 1093 cm -1 represented a 5.7-fold peak intensity at 341 cm -1 .

[0262] The X-ray diffraction pattern and the scanning electron microscope image of catalyst S13 were similar to those in Fig. 3 and Fig. 4, respectively.

[0263] Catalyst S13 had a silicon-to-titanium molar ratio of 27 and a boron-to-silicon molar ratio of 0.08.

[0264] Catalyst S13 was characterized by a micropore volume of 0.05 cm 3 / g, the proportion of micropore volume in relation to the total pore volume, amounting to 1.7%, and mechanical strength, amounting to 60 N / cm.

[0265] Example 14

[0266] (1) 90g of Ti-MWW molecular sieve powder having a silicon-titanium molar ratio of 20, 90g of amorphous binder (this amorphous binder contained 75g of silica sol containing silica in a weight fraction of 40% and 15g of boric acid), 3g of sesbania powder and 9g of sodium fluoride were mixed by mechanical stirring, and then 80g of water was added to the resulting mixture. After mixing and stirring for 4 hours, a solid mixture was obtained, which was sent to molding by mechanical extrusion, dried at 100°C for 8 hours, and then calcined at 550°C for 6 hours to obtain a cylindrical molded product.

[0267] (2) 90 g of the cylindrical molded product obtained in step (1) was placed onto 60 g of a 3 mol / L piperidine solution without contact between them to achieve crystallization at 170°C for 2 days in a closed environment. The product was washed with water and dried at 100°C for 8 hours to obtain cylindrical catalyst precursor A.

[0268] (3) 60 g of the cylindrical catalyst precursor A obtained in step (2) and a 2 mol / L nitric acid solution were mixed at a weight ratio of 1:50, and then 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 the cylindrical catalyst precursor B.

[0269] (4) 40 g of the cylindrical catalyst precursor B obtained in step (3), ammonium fluoride and 3 mol / L hexamethyleneimine solution were mixed at a weight ratio of 1:0.2:20, and then 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-containing catalyst, which was given the code name S14.

[0270] Catalyst S14 was sent for studies in accordance with the above description.

[0271] The X-ray photoelectron spectrum of catalyst S14 showed peaks at 458.9, 460.3, 464.8 and 465.9 eV.

[0272] The ultraviolet Raman spectrum of catalyst S14 showed peaks at 342, 484, 700 and 1097 cm -1 Peak intensity at 700 cm -1 represented a 5-fold peak intensity at 342 cm -1, and the peak intensity at 1097 cm -1 represented a 4.8-fold peak intensity at 342 cm -1 .

[0273] The X-ray diffraction pattern and the scanning electron microscope image of catalyst S14 were similar to those in Fig. 3 and Fig. 4, respectively.

[0274] Catalyst S14 had a silicon-to-titanium molar ratio of 39 and a boron-to-silicon molar ratio of 0.018.

[0275] Catalyst S14 was characterized by a micropore volume of 0.08 cm 3 / g, the proportion of micropore volume in relation to the total pore volume, amounting to 3.2%, and mechanical strength, amounting to 62 N / cm.

[0276] Example 15

[0277] (1) 90g of Ti-MWW molecular sieve powder having a silicon-to-titanium molar ratio of 20, 90g of an amorphous binder (this amorphous binder contained 75g of silica sol containing silica in a weight fraction of 40% and 15g of boric acid), 3g of sesbania powder and 9g of sodium fluoride were mixed by mechanical stirring, and then 80g of water was added to the resulting mixture. After mixing and stirring for 4 hours, a solid mixture was obtained, which was sent to molding by mechanical extrusion, dried at 100°C for 8 hours, and then calcined at 550°C for 6 hours to obtain a cylindrical molded product.

[0278] (2) 90g of the cylindrical molded product obtained in step (1) was placed onto 60g of a 3 mol / L piperidine solution without contact between them to achieve crystallization at 170°C for 2 days in a closed environment. The product was washed with water and dried at 100°C for 8 hours to obtain cylindrical catalyst precursor A.

[0279] (3) 60 g of the cylindrical catalyst precursor A obtained in step (2) and a 2 mol / L nitric acid solution were mixed at a weight ratio of 1:50, and then 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 the cylindrical catalyst precursor B.

[0280] (4) 40 g of the cylindrical catalyst precursor B obtained in step (3), potassium fluoride and 15 mol / L piperidine solution were mixed at a weight ratio of 1:0.4:2, and then 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-containing catalyst, which was given the code name S15.

[0281] Catalyst S15 was sent for studies in accordance with the above description.

[0282] The X-ray photoelectron spectrum of catalyst S15 showed peaks at 459.0, 460.2, 464.9 and 465.8 eV.

[0283] The ultraviolet Raman spectrum of catalyst S15 showed peaks at 342, 485, 701 and 1095 cm -1 . Peak intensity at 701 cm -1 represented a 6.8-fold peak intensity at 342 cm -1 , and the peak intensity at 1095 cm-1 represented a 3.2-fold peak intensity at 342 cm -1 .

[0284] The X-ray diffraction pattern and the scanning electron microscope image of catalyst S15 were similar to those in Fig. 3 and Fig. 4, respectively.

[0285] Catalyst S15 had a silicon-to-titanium molar ratio of 37 and a boron-to-silicon molar ratio of 0.025.

[0286] Catalyst S15 was characterized by a micropore volume of 0.15 cm 3 / g, the proportion of micropore volume in relation to the total pore volume, amounting to 7.5%, and mechanical strength, amounting to 64 N / cm.

[0287] Example 16

[0288] (1) 90g of Ti-MWW molecular sieve powder having a silicon-to-titanium molar ratio of 20, 90g of amorphous binder (this amorphous binder contained 75g of silica sol containing silica in a weight fraction of 40% and 15g of boric acid), 3g of sesbania powder and 9g of sodium fluoride were mixed by mechanical stirring, and then 80g of water was added to the resulting mixture. After mixing and stirring for 4 hours, a solid mixture was obtained, which was sent to molding by mechanical extrusion, dried at 100°C for 8 hours, and then calcined at 550°C for 6 hours to obtain a cylindrical molded product.

[0289] (2) 90g of the cylindrical molded product obtained in step (1) was placed onto 60g of a 3mol / L piperidine solution without contact between them to achieve crystallization at 170°C for 2 days in a closed environment. The product was washed with water and dried at 100°C for 8 hours to obtain cylindrical catalyst precursor A.

[0290] (3) 60 g of the cylindrical catalyst precursor A obtained in step (2) and a 2 mol / L nitric acid solution were mixed at a weight ratio of 1:50, and then 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 the cylindrical catalyst precursor B.

[0291] (4) 40 g of the cylindrical catalyst precursor B obtained in step (3), sodium fluoride and a 0.3 mol / L piperidine solution were mixed at a weight ratio of 1:0.05:20, and then reacted at 130°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-containing catalyst, which was given the code name S16.

[0292] Catalyst S16 was sent for studies in accordance with the above description.

[0293] The X-ray photoelectron spectrum of catalyst S16 showed peaks at 458.9, 460.3, 464.8 and 465.9 eV.

[0294] The ultraviolet Raman spectrum of catalyst S16 showed peaks at 344, 482, 698 and 1098 cm -1 . Peak intensity at 698 cm -1 represented a 3.3-fold peak intensity at 344 cm -1, and the peak intensity at 1098 cm -1 represented a 6.9-fold peak intensity at 344 cm -1 .

[0295] The X-ray diffraction pattern and the scanning electron microscope image of catalyst S16 were similar to those in Fig. 3 and Fig. 4, respectively.

[0296] Catalyst S16 was characterized by a silicon-to-titanium molar ratio of 36 and a boron-to-silicon molar ratio of 0.01.

[0297] Catalyst S16 was characterized by a micropore volume of 0.03 cm 3 / g, the proportion of micropore volume in relation to the total pore volume, amounting to 1%, and mechanical strength, amounting to 57 N / cm.

[0298] Worked Examples 17-24

[0299] Liquid-phase continuous epoxidation of propylene was carried out in the presence of the Ti-MWW molecular sieve-containing catalysts prepared in Examples 1, 2, 3, 6, 11, 12, 15, and 16 to evaluate the corresponding catalytic performance characteristics.

[0300] 2 g of the above-described Ti-MWW molecular sieve-containing catalysts were ground to 20-40 mesh particles and loaded into a stainless steel tubular reactor, with both ends of the tubular reactor filled with glass beads. The reaction was carried out under conditions of a temperature of 40°C and a pressure of 2.0 MPa, with an inlet from the bottom and an outlet from the top of the tubular reactor. Nitrogen was used to set the propylene pressure to 2.5 MPa to ensure complete liquefaction of propylene. The propylene feed solution, which was separately introduced, is referred to as "feed solution A". An aqueous solution with a hydrogen peroxide content of 30% by weight was used to prepare an aqueous solution of piperidine in hydrogen peroxide with a concentration of 15 ppm, which was mixed with acetonitrile as a solvent.The resulting mixture was designated "feed solution B." The two feed solutions were introduced separately using plunger pumps and premixed before being introduced into the tubular reactor. A sample of the mixed feed solution entering the tubular reactor was collected and analyzed as described above. The mixed feed solution stream contained propylene at a mass fraction of 18.7%, acetonitrile at a mass fraction of 61.0%, and the molar ratio of propylene to hydrogen peroxide was 1:0.4. The catalyst flow rate per unit total mass of the feed solutions was 6 ml⋅g. кат. -1 ⋅h -1 A sample of the reaction liquid exiting the tubular reactor was collected and analyzed as described above. The results are presented in Table 1.

[0301]

[0302] Worked Examples 25-28

[0303] Liquid-phase continuous epoxidation of allyl chloride was carried out in the presence of the Ti-MWW molecular sieve-containing catalysts prepared in Examples 1, 6, 11, and 16 to evaluate the corresponding catalytic performance characteristics.

[0304] 2 g of Ti-MWW molecular sieve-containing catalysts were crushed to 20-40 mesh particles and loaded into a stainless steel tubular reactor, both ends of which were filled with glass beads. The reaction was carried out under conditions of a temperature of 60°C and a pressure of 0.6 MPa, with an inlet from the bottom and an outlet from the top of the tubular reactor. The feed solution of allyl chloride, which was separately introduced, is referred to as "feed solution A". An aqueous solution with a hydrogen peroxide content of 30% by weight was used to prepare an aqueous solution of hexamethyleneimine in 50 ppm hydrogen peroxide, which was mixed with acetonitrile as a solvent. The resulting mixture was referred to as "feed solution B".The two feed solutions were introduced separately using plunger pumps and premixed before being introduced into the tubular reactor. A sample of the mixed feed solution entering the tubular reactor was collected and analyzed as described above. The mixed feed solution stream contained allyl chloride at a mass fraction of 27.7%, acetonitrile at a mass fraction of 54.2%, and the molar ratio of allyl chloride to hydrogen peroxide was 1:0.4. The catalyst flow rate per unit total mass of the feed solutions was 4 ml⋅g. кат . -1 ⋅h -1 A sample of the reaction liquid exiting the tubular reactor was collected and analyzed as described above. The results are presented in Table 2.

[0305]

[0306] Comparative Example 1

[0307] (1) 90g of Ti-MWW molecular sieve powder having a silicon-to-titanium molar ratio of 20, 90g of amorphous binder (this amorphous binder contained 75g of silica sol containing silica in a weight fraction of 40% and 15g of boric acid), 3g of sesbania powder and 9g of sodium fluoride were mixed by mechanical stirring, and then 80g of water was added to the resulting mixture. After mixing and stirring for 4 hours, a solid mixture was obtained, which was sent to molding by mechanical extrusion, dried at 100°C for 8 hours, and then calcined at 550°C for 6 hours to obtain a cylindrical molded product.

[0308] (2) 60 g of the cylindrical molded product obtained in step (1) and a 2 mol / L nitric acid solution were mixed at a weight ratio of 1:50, and then 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.

[0309] (3) 40 g of the cylindrical catalyst precursor obtained in step (2), ammonium fluoride and a 3 mol / L piperidine solution were mixed at a weight ratio of 1:0.1:10, and then 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-containing catalyst, which was given the code name D1.

[0310] Catalyst D1 was sent for studies in accordance with the above description.

[0311] The X-ray photoelectron spectrum of catalyst D1, which is illustrated in Fig. 5, shows peaks at 459.5 and 465.1 eV. These peaks correspond to tetracoordinated titanium fragments.

[0312] The ultraviolet Raman spectrum of catalyst D1, which is illustrated in Fig. 6, which only showed peaks at 491 and 1080 cm -1 . However, there was no peak corresponding to the MWW structure. Peaks at 491 and 1080 cm -1The observed tetracoordinated titanium fragments corresponded to these structures. These results were primarily due to the fact that the catalyst still contained amorphous binders that had not been converted into molecular sieve components. The presence of amorphous binders obscured the molecular sieve, making it impossible to detect the MWW structure of the molecular sieve using ultraviolet Raman spectroscopy.

[0313] The X-ray diffraction pattern of catalyst D1 is shown in Fig. 7. It contains diffraction peaks at 2θ angles of 3.3°, 6.6°, 7.2°, 7.9°, 9.7°, and 26.1°. The intensity of the diffraction peak at 2θ angle of 7.2° reached approximately 2500, which is significantly lower than that of catalyst S1, indicating that the bulk of catalyst D1 still lacked the MWW structure but had a low degree of crystallinity. In addition, there were intense broad diffraction peaks in the region of 17.5-30°, which further indicated the presence of amorphous fragments in catalyst D1.

[0314] The scanning electron microscope image is shown in Fig. 8. The catalyst exhibits a lamellar morphology in which nanoparticles are observed. This further indicates the presence of amorphous fragments in catalyst D1. This is consistent with the results illustrated in Fig. 7.

[0315] Catalyst D1 was characterized by a silicon-to-titanium molar ratio of 30 and a boron-to-silicon molar ratio of 0.06.

[0316] Catalyst D1 was characterized by a micropore volume of 0.04 cm 3 / g, the proportion of micropore volume in relation to the total pore volume, amounting to 1.4%, and mechanical strength, amounting to 29 N / cm.

[0317] Comparative Example 2

[0318] (1) 90g of Ti-MWW molecular sieve powder having a silicon-to-titanium molar ratio of 20, 90g of amorphous binder (this amorphous binder contained 75g of silica sol containing silica in a weight fraction of 40% and 15g of boric acid), 3g of sesbania powder and 9g of sodium fluoride were mixed by mechanical stirring, and then 80g of water was added to the resulting mixture. After mixing and stirring for 4 hours, a solid mixture was obtained, which was sent to molding by mechanical extrusion, dried at 100°C for 8 hours, and then calcined at 550°C for 6 hours to obtain a cylindrical molded product.

[0319] (2) 90g of the cylindrical molded product obtained in step (1) was placed onto 60g of a 3mol / L piperidine solution without contact to achieve crystallization at 170°C for 2 days in a closed environment. The product was washed with water and dried at 100°C for 8 hours to obtain a cylindrical catalyst precursor.

[0320] (3) 40 g of the cylindrical catalyst precursor obtained in step (2), ammonium fluoride and a 3 mol / L piperidine solution were mixed at a weight ratio of 1:0.1:10, and then 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-containing catalyst, which was given the code name D2.

[0321] Catalyst D2 was sent for studies in accordance with the above description.

[0322] According to observations, the X-ray photoelectron spectrum of catalyst D2 showed peaks at 460.0 and 465.6 eV. These peaks corresponded to tetracoordinated titanium framework fragments.

[0323] The ultraviolet Raman spectrum of catalyst D2, which is illustrated in Fig. 9, shows peaks at 342, 491 and 1090 cm -1 Peak intensity at 1090 cm -1 represented an 11.2-fold peak intensity at 342 cm -1 This indicates the presence of a large number of framework tetracoordinated titanium fragments.

[0324] The X-ray diffraction pattern and the scanning electron microscope image of catalyst D2 were similar to those in Fig. 3 and Fig. 4, respectively.

[0325] Catalyst D2 was characterized by a silicon-titanium molar ratio of 31 and a boron-silicon molar ratio of 0.05.

[0326] Catalyst D2 was characterized by a micropore volume of 0.08 cm 3 / g, the proportion of micropore volume in relation to the total pore volume, amounting to 3.2%, and mechanical strength, amounting to 68 N / cm.

[0327] Comparative Example 3

[0328] (1) 90g of Ti-MWW molecular sieve powder having a silicon-to-titanium molar ratio of 20, 90g of amorphous binder (this amorphous binder contained 75g of silica sol containing silica in a weight fraction of 40% and 15g of boric acid), 3g of sesbania powder and 9g of sodium fluoride were mixed by mechanical stirring, and then 80g of water was added to the resulting mixture. After mixing and stirring for 4 hours, a solid mixture was obtained, which was sent to molding by mechanical extrusion, dried at 100°C for 8 hours, and then calcined at 550°C for 6 hours to obtain a cylindrical molded product.

[0329] (2) 90g of the cylindrical molded product obtained in step (1) was placed onto 60g of a 3mol / L piperidine solution without contact to achieve crystallization at 170°C for 2 days in a closed environment. The product was washed with water and dried at 100°C for 8 hours to obtain a cylindrical catalyst precursor.

[0330] (3) 60 g of the cylindrical catalyst precursor obtained in step (2) and a 2 mol / L nitric acid solution were mixed at a weight ratio of 1:50, and then 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 Ti-MWW molecular sieve-containing catalyst, which was given the designation D3.

[0331] Catalyst D3 was sent for studies in accordance with the above description.

[0332] According to observations, the X-ray photoelectron spectrum of catalyst D3 showed peaks at 460.0 and 465.6 eV. These peaks corresponded to tetracoordinated titanium framework fragments.

[0333] The ultraviolet Raman spectrum of catalyst D3, which is illustrated in Fig. 10, shows peaks at 343, 490 and 1092 cm -1 . Peak intensity at 1092 cm -1 represented a 10.2-fold peak intensity at 343 cm -1 This indicates the presence of a large number of framework tetracoordinated titanium fragments.

[0334] The X-ray diffraction pattern and the scanning electron microscope image of catalyst D3 were similar to those in Fig. 3 and Fig. 4, respectively.

[0335] Catalyst D3 was characterized by a silicon-to-titanium molar ratio of 36 and a boron-to-silicon molar ratio of 0.017.

[0336] Catalyst D3 was characterized by a micropore volume of 0.16 cm 3 / g, the proportion of micropore volume in relation to the total pore volume, amounting to 7.8%, and mechanical strength, amounting to 58 N / cm.

[0337] Comparative Example 4

[0338] (1) 90g of Ti-MWW molecular sieve powder having a silicon-titanium molar ratio of 20, 90g of amorphous binder (this amorphous binder contained 75g of silica sol containing silica at a weight fraction of 40% and 15g of boric acid) and 3g of sesbania powder were mixed by mechanical stirring, and then 80g of water was added to the resulting mixture. After mixing and stirring for 4 hours, a solid mixture was obtained, which was sent to molding by mechanical extrusion, dried at 100°C for 8 hours, and then calcined at 550°C for 6 hours to obtain a cylindrical molded product.

[0339] (2) 90g of the cylindrical molded product obtained in step (1) was placed onto 60g of a 3mol / L piperidine solution without contact between them to achieve crystallization at 170°C for 2 days in a closed environment. The product was washed with water and dried at 100°C for 8 hours to obtain cylindrical catalyst precursor A.

[0340] (3) 60 g of the cylindrical catalyst precursor A obtained in step (2) and a 2 mol / L nitric acid solution were mixed at a weight ratio of 1:50, and then 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 the cylindrical catalyst precursor B.

[0341] (4) 40 g of the cylindrical catalyst precursor B obtained in step (3), ammonium fluoride and a 3 mol / L piperidine solution were mixed at a weight ratio of 1:0.1:10, and then 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-containing catalyst, which was given the code name D4.

[0342] Catalyst D4 was sent for studies in accordance with the above description.

[0343] According to observations, the X-ray photoelectron spectrum of catalyst D4 showed peaks at 459.7 and 465.4 eV. These peaks correspond to tetracoordinated titanium fragments.

[0344] The ultraviolet Raman spectrum of catalyst D4, which is illustrated in Fig. 11, shows peaks at 340, 488 and 1087 cm -1 . Peak intensity at 1087 cm-1 represented a 10.9-fold peak intensity at 340 cm -1 This indicated the presence of a large number of tetracoordinated titanium fragments.

[0345] The X-ray diffraction pattern and the scanning electron microscope image of catalyst D4 were similar to those in Fig. 7 and Fig. 8, respectively.

[0346] Catalyst D4 was characterized by a silicon-to-titanium molar ratio of 33 and a boron-to-silicon molar ratio of 0.012.

[0347] Catalyst D4 was characterized by a micropore volume of 0.05 cm 3 / g, the proportion of micropore volume in relation to the total pore volume, amounting to 1.7%, and mechanical strength, amounting to 36 N / cm.

[0348] Comparative Example 5

[0349] (1) 90g of Ti-MWW molecular sieve powder having a silicon-titanium molar ratio of 20, 90g of amorphous binder (this amorphous binder contained 75g of silica sol containing silica in a weight fraction of 40% and 15g of boric acid), 3g of sesbania powder and 9g of sodium fluoride were mixed by mechanical stirring, and then 80g of water was added to the resulting mixture. After mixing and stirring for 4 hours, a solid mixture was obtained, which was sent to molding by mechanical extrusion, dried at 100°C for 8 hours, and then calcined at 550°C for 6 hours to obtain a cylindrical molded product.

[0350] (2) 90g of the cylindrical molded product obtained in step (1) was placed onto 60g of a 3mol / L piperidine solution without contact between them to achieve crystallization at 170°C for 2 days in a closed environment. The product was washed with water and dried at 100°C for 8 hours to obtain cylindrical catalyst precursor A.

[0351] (3) 60 g of the cylindrical catalyst precursor A obtained in step (2) and a 2 mol / L nitric acid solution were mixed at a weight ratio of 1:50, and then 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 the cylindrical catalyst precursor B.

[0352] (4) 40 g of the cylindrical catalyst precursor B obtained in step (3) and a 3 mol / L piperidine solution were mixed at a weight ratio of 1:10, and then 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-containing catalyst, which was given the designation D5.

[0353] Catalyst D5 was sent for studies in accordance with the above description.

[0354] According to observations, the X-ray photoelectron spectrum of catalyst D5 showed peaks at 460.6 and 466.2 eV. These peaks correspond to tetracoordinated titanium fragments.

[0355] The ultraviolet Raman spectrum of catalyst D5, which is illustrated in Fig. 12, shows peaks at 342, 490 and 1102 cm -1 . Peak intensity at 1102 cm -1represented a 10.3-fold peak intensity at 342 cm -1 This indicated the presence of a large number of tetracoordinated titanium framework fragments.

[0356] The X-ray diffraction pattern and the scanning electron microscope image of catalyst D5 were similar to those in Fig. 3 and Fig. 4, respectively.

[0357] Catalyst D5 was characterized by a silicon-to-titanium molar ratio of 36 and a boron-to-silicon molar ratio of 0.017.

[0358] Catalyst D5 was characterized by a micropore volume of 0.04 cm 3 / g, the proportion of micropore volume in relation to the total pore volume, amounting to 1.3%, and mechanical strength, amounting to 74 N / cm.

[0359] Comparative Example 6

[0360] (1) 90g of Ti-MWW molecular sieve powder having a silicon-titanium molar ratio of 20, 90g of amorphous binder (this amorphous binder contained 75g of silica sol containing silica in a weight fraction of 40% and 15g of boric acid), 3g of sesbania powder and 9g of sodium fluoride were mixed by mechanical stirring, and then 80g of water was added to the resulting mixture. After mixing and stirring for 4 hours, a solid mixture was obtained, which was sent to molding by mechanical extrusion, dried at 100°C for 8 hours, and then calcined at 550°C for 6 hours to obtain a cylindrical molded product, which was given the symbol D6.

[0361] Catalyst D6 was sent for studies in accordance with the above description.

[0362] The X-ray photoelectron spectrum of catalyst D6, which is illustrated in Fig. 13, shows peaks at 460.2 and 465.8 eV. These peaks correspond to tetracoordinated titanium fragments.

[0363] The ultraviolet Raman spectrum of catalyst D6, which is illustrated in Fig. 14, shows peaks at 343, 492 and 1094 cm -1 . Peak intensity at 1094 cm -1 represented a 9.7-fold peak intensity at 343 cm -1 This indicates the presence of a large number of framework tetracoordinated titanium fragments.

[0364] The X-ray photoelectron spectrum and ultraviolet Raman spectrum of the Ti-MWW molecular sieve powder were similar to those in Fig. 13 and Fig. 14, respectively, showing that the mechanical extrusion molding did not affect the state of the titanium fragments of the D6 catalyst.

[0365] The X-ray diffraction pattern and the scanning electron microscope image of catalyst D6 were similar to those in Fig. 7 and Fig. 8, respectively.

[0366] Catalyst D6 was characterized by a silicon-to-titanium molar ratio of 38 and a boron-to-silicon molar ratio of 0.11.

[0367] Catalyst D6 was characterized by a micropore volume of 0.13 cm 3 / g, the proportion of micropore volume in relation to the total pore volume, amounting to 5.4%, and mechanical strength, amounting to 28 N / cm.

[0368] Comparative Example 7

[0369] (1) 90g of Ti-MWW molecular sieve powder having a silicon-to-titanium molar ratio of 20, 90g of amorphous binder (this amorphous binder contained 75g of silica sol containing silica at a weight fraction of 40% and 15g of boric acid), 3g of sesbania powder and 9g of sodium fluoride were mixed by mechanical stirring, and then 80g of water was added to the resulting mixture. After mixing and stirring for 4 hours, a solid mixture was obtained, which was formed by mechanical extrusion, dried at 100°C for 8 hours, and then calcined at 550°C for 6 hours to obtain a cylindrical molded product, which was given the symbol D7.

[0370] Catalyst D7 was sent for studies in accordance with the above description.

[0371] The X-ray photoelectron spectrum of catalyst D7, which is illustrated in Fig. 15, shows peaks at 458.0 and 463.8 eV. These peaks correspond to extraframework hexacoordinated titanium fragments.

[0372] The ultraviolet Raman spectrum of catalyst D7, which is illustrated in Fig. 16, shows peaks at 440 and 700 cm -1 These peaks correspond to extraframework hexacoordinated titanium fragments.

[0373] The X-ray photoelectron spectrum and ultraviolet Raman spectrum of the synthesized Ti-MWW molecular sieve powder were similar to those in Fig. 15 and Fig. 16, respectively, showing that the mechanical extrusion molding did not affect the state of the titanium fragments of the D7 catalyst.

[0374] The X-ray diffraction pattern and the scanning electron microscope image of catalyst D7 were similar to those in Fig. 7 and Fig. 8, respectively.

[0375] Catalyst D7 was characterized by a silicon-to-titanium molar ratio of 37 and a boron-to-silicon molar ratio of 0.12.

[0376] Catalyst D7 was characterized by a micropore volume of 0.12 cm 3 / g, the proportion of micropore volume in relation to the total pore volume, amounting to 5.3%, and mechanical strength, amounting to 26 N / cm.

[0377] Comparative Worked Examples 8-11

[0378] Working Examples 17–24 were reproduced using the Ti-MWW molecular sieve-containing catalysts D1–D7 obtained in Comparative Examples 1–7, respectively, to evaluate the corresponding catalytic performance characteristics. The results are presented below in Table 3.

[0379]

[0380] The embodiments of the present invention have been described in detail above. However, they do not limit the present invention. Various simple modifications to the embodiments of the present invention can be made within the technical scope of the present invention, including combinations of various technical features in any other suitable way. These simple modifications and combinations should also be considered as part of the content described herein and are within the scope of legal protection of the present invention.

Claims

1. A Ti-MWW molecular sieve-containing catalyst for olefin epoxidation, the X-ray photoelectron energy spectrum of the catalyst showing peaks at 458.9 ± 0.2 eV and 464.8 ± 0.2 eV.

2. A Ti-MWW molecular sieve containing catalyst for olefin epoxidation, the X-ray photoelectron energy spectrum of which exhibits peaks at 458.9 ± 0.1 eV, 460.3 ± 0.1 eV, 464.8 ± 0.1 eV and 465.9 ± 0.1 eV.

3. The catalyst according to claim 1 or 2, characterized in that the ultraviolet Raman spectrum of the catalyst contains peaks at 343 ± 4 cm -1 , 484 ± 4 cm -1 , 699 ± 4 cm -1 and 1097 ± 4 cm -1 .

4. The catalyst according to item 3, characterized in that the intensity of the peak at 699 ± 4 cm -1 represents 0.5-10 times the intensity of the peak at 343 ± 4 cm -1 , and the peak intensity at 1097 ± 4 cm -1represents 0.5-10 times the intensity of the peak at 343 ± 4 cm -1 .

5. The catalyst according to claim 1 or 2, characterized in that the catalyst has a molar ratio of silicon to titanium of 10-200; the catalyst additionally contains at least one element from boron and aluminum; wherein the catalyst has a molar ratio of boron to silicon of 0-0.1, and a molar ratio of aluminum to silicon of 0-0.

1.

6. The catalyst according to claim 1 or 2, characterized in that the catalyst has a molar ratio of silicon to titanium of 25-100; the catalyst additionally contains boron; wherein the catalyst has a molar ratio of boron to silicon of 0.005-0.03, and a molar ratio of aluminum to silicon of 0-0.

05.

7. The catalyst according to item 1 or 2, characterized in that the catalyst has a micropore volume of 0.03-0.15 cm 3 / g; and the proportion of micropore volume in relation to the total pore volume, amounting to 1-7.5%.

8. The catalyst according to item 1 or 2, characterized in that the catalyst has a micropore volume of 0.05-0.10 cm 3 / g; and the proportion of micropore volume in relation to the total pore volume, amounting to 1.7-5%.

9. The catalyst according to claim 1 or 2, characterized in that the catalyst exists entirely in the form of a crystalline structure; and the catalyst has a mechanical strength of 30-90 N / cm.

10. A method for preparing a Ti-MWW molecular sieve containing catalyst for the epoxidation of olefins, comprising the following steps: (1) subjecting a Ti-MWW molecular sieve powder, a binder, a pore-forming agent, and a fluoride to molding and calcination to form a molded product, wherein the binder comprises a silicon source and at least one substance selected from the group consisting of a boron source and an aluminum source; in terms of oxides, the silicon source, the boron source, and the aluminum source are present in a molar ratio of 1:x:y, where x = 0-0.5, y = 0-0.5, and x+y = 0.02-1; wherein the silicon source is at least one substance selected from the group consisting of silica sol, sodium silicate, white carbon black, and ethyl orthosilicate; the boron source is at least one substance selected from the group consisting of boric acid, boron oxide, and borates;the aluminum source is at least one substance selected from the group consisting of aluminum oxide, aluminum hydroxide, sodium meta-aluminate, aluminum nitrate and aluminum sulfate, wherein the pore-forming substance is at least one substance selected from the group consisting of sesbania powder, cellulose, chitosan, lignin, starch, polyethylene glycol, a poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer (P123) and a poly(ethylene oxide)-poly(propylene oxide) copolymer (F127); wherein the fluoride is at least one substance selected from the group consisting of sodium fluoride, potassium fluoride and ammonium fluoride; wherein the powdered molecular sieve Ti-MWW, the binder, the pore-forming agent and the fluoride are used in a weight ratio of 1:(0.1-1.5):(0.01-0.1):(0.01-0.4); (2) crystallizing the shaped product obtained in step (1) in the presence of an organic amine solution to obtain a catalyst precursor A; wherein the organic amine is at least one substance selected from the group consisting of piperidine and hexamethyleneimine, and wherein the shaped product and the organic amine solution are used in a weight ratio of (0.1-10):1; (3) treating the catalyst precursor A obtained in step (2) with an acid solution and calcining to obtain a catalyst precursor B; wherein the acid solution is at least one substance selected from the group consisting of solutions of nitric acid, hydrochloric acid, sulfuric acid, formic acid, acetic acid and oxalic acid, and wherein the catalyst precursor A and the acid solution are used in a weight ratio of 1:(10-80); (4) treating the catalyst precursor B obtained in step (3) with a solution of an organic amine in the presence of fluoride to obtain a catalyst; wherein the organic amine is at least one substance selected from the group consisting of piperidine and hexamethyleneimine, and wherein the catalyst precursor B, the fluoride and the organic amine solution are present in a weight ratio of 1:(0.05-0.4):(2-20).

11. The method according to claim 10, characterized in that step (2) includes the following step: placing the molded product obtained in step (1) on a solution of an organic amine, but not in contact with the solution of an organic amine, the solution of an organic amine has a concentration of 0.3-15 mol / l, and crystallization is carried out at a temperature of 130-190°C for 1-9 days.

12. The method according to claim 10, characterized in that step (3) includes the following step: bringing the catalyst precursor A obtained in step (2) and the acid solution into contact and carrying out the reaction, wherein the acid solution has a concentration of 0.3-12 mol / l, and the treatment with the acid solution is carried out at a temperature of 60-130°C for 4-48 hours.

13. The method according to claim 10, characterized in that in step (4) the organic amine solution has a concentration of 0.3-15 mol / l, and the treatment with the organic amine solution is carried out at a temperature of 130-190°C for 4-48 hours.

14. The method according to claim 10, characterized in that in step (1), calcination is carried out at a temperature of 450-650°C in an oxygen-containing atmosphere for 4-12 hours; and in step (3), calcination is carried out at a temperature of 450-650°C in an oxygen-containing atmosphere for 4-12 hours.

15. A Ti-MWW molecular sieve containing catalyst for the epoxidation of olefins prepared by the method according to any one of claims 10 to 14.

16. Use of a catalyst according to any one of claims 1 to 9 or a catalyst according to claim 15 in the epoxidation of olefins.

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