Titanium silicalite catalyst enriched in six-coordinated titanium species and its preparation and use

Abstract

The application discloses a titanium-silicon molecular sieve catalyst rich in six-coordinated titanium species and a preparation method and application thereof, characterized by mixing inorganic titanium-silicon molecular sieve precursors with organic quaternary ammonium salt hydroxides, and performing a synthesis reaction at a temperature of 50-200 DEG C in a high-pressure hydrothermal reaction kettle to obtain a catalyst with titanium, silicon and oxygen as skeleton elements, the titanium-silicon molecular sieve rich in six-coordinated titanium species in the skeleton, and the six-coordinated titanium content accounting for 50-95% of the total titanium content; the catalyst can be used in selective epoxidation of hydrocarbons, epoxidation of furan organic matter, desulfurization reaction of thiophene organic matter and ketone ammoxidation reaction. The application makes up for the defects of the prior art preparation method, and the catalyst has good catalytic oxidation performance and catalytic stability, and the catalytic activity in selective epoxidation of hydrocarbons, epoxidation of furan organic matter, desulfurization reaction of thiophene organic matter and ketone ammoxidation reaction is obviously improved.

Description

Technical Field

[0001] This invention relates to the field of inorganic chemical synthesis and catalytic application technology, and in particular to a method for preparing a titanium-silicon molecular sieve catalyst rich in six-coordinate titanium species and its application in selective epoxidation of hydrocarbons, epoxidation of furan organic compounds, desulfurization of thiophene organic compounds and ammonia oxidation of ketones. Background Technology

[0002] Titanium silicate molecular sieves, formed by isomorphously substituting transition metal titanium atoms into the silicate framework, can be used as heterogeneous catalysts, especially in liquid-phase selective oxidation reactions. In 1983, ENI first synthesized TS-1 titanium silicate molecular sieves under hydrothermal conditions (US Patent 1983,4410501) and applied it to selective oxidation reactions. The most important industrial application of TS-1 is the catalytic epoxidation of olefins involving hydrogen peroxide. The resulting product can be used to produce plastics (such as polyurethane), with water as the only byproduct. The most typical reaction is the epoxidation of propylene to produce propylene oxide, a process that produces 1 million tons of propylene oxide annually in the global chemical industry. On the other hand, ENI developed an industrial ammoniation process of TS-1 / H2O2. The product, cyclohexanone oxime, is a key precursor for the indirect production of nylon-6. With global nylon-6 production projected to reach 8.9 million metric tons per year by 2024, the demand for cyclohexanone oxime will increase simultaneously. ENI established a 10,000-ton / year hydroquinone production plant using TS-1, which began normal operation in 1986. Compared to traditional oxidation processes, titanium silicate molecular sieves offer milder reaction conditions, simpler processes, environmental friendliness, and better conversion and selectivity.

[0003] Besides the traditional TS-1, various titanium-silicon molecular sieves with different structures have been developed, such as Ti-MWW (Journal of Physical Chemistry B, 2001, 105, 2897), Ti-MOR (J. Catal., 1997, 168, 400), and Ti-Beta (Chem. Comm., 1992, 589). Among them, Ti-MWW exhibits excellent catalytic performance in the selective epoxidation of hydrocarbons and the ammoxidation of aldehydes and ketones. For example, patent CN 1709574A discloses a titanium-silicon molecular sieve catalyst with an MWW structure, its preparation method, and its applications, which shows good activity and high selectivity in the oxime reactions of olefins and olefin alcohols, olefin ethers, and cyclohexanone. Patent CN 101003376A proposes a method for synthesizing alkali-modified titanium-containing molecular sieves, which significantly improves their catalytic activity and stability in olefin catalytic reactions. In addition, CN 103949289A prepared a composite titanium silicate borate Ti-MWW catalyst. The presence of organic ammonium makes the framework more hydrophobic and reduces defect sites, thereby significantly improving the catalytic activity in the selective oxidation of hydrocarbons and the ammoxidation of ketones. CN 116924430A provides a method for preparing and applying a microporous composite MWW structured titanium silicate borate molecular sieve, which has a mesoporous and open pore structure and exhibits mild reaction conditions, high activity, and few by-products in the epoxidation of olefins and the ammoxidation of aldehydes and ketones.

[0004] With the development and application of titanium-silicon molecular sieve catalysts, researchers have studied the state of active sites of titanium. The most traditional catalytic site is tetracoordinate titanium – “Ti(OSi)4”, which corresponds to an absorption peak near 210 nm in the ultraviolet-visible spectrum (UV-Vis) (J. Catal., 1992, 133, 220). Secondly, corresponding to titanium active species near 260 nm in UV-Vis, various highly active six-coordinate titanium coordination states have been proposed – “Ti(OSi)2(H2O)2(OH)2” (Chem. Eur. J., 2012, 18, 13854), “Ti(OSi)2(H2O)(OH)2(PI)” (Chem. Commun., 2015, 51, 9010), and “Ti(OSi)2(OH)4” (Applied Catalysis B: Environmental, 2023, 325, 122396). Besides the titanium active species mentioned above, other titanium coordination states exist: pentacoordinate titanium – “Ti(OSi)3(OH)2” (Applied Catalysis B: Environmental, 2023, 325, 122396), and binuclear titanium – “(SiO)3Ti-OO-Ti(OSi)3” (Nature, 2020, 586, 708). However, current methods for preparing titanium-silicon molecular sieves can only produce those containing a small amount of hexacoordinate titanium species; most titanium species in the catalyst exist in the form of tetracoordinate titanium, and the catalytic selective oxidation activity is low. Furthermore, the preparation of titanium-silicon molecular sieve catalysts containing hexacoordinate titanium often simultaneously produces inactive anatase species. Therefore, a synthetic method for preparing highly active titanium-silicon molecular sieves rich in hexacoordinate titanium is still lacking. Summary of the Invention

[0005] The purpose of this invention is to provide a titanium-silicon molecular sieve catalyst rich in six-coordinate titanium species, its preparation method, and its application. The catalyst is prepared by hydrothermal synthesis of an inorganic titanium-silicon molecular sieve precursor with an organic quaternary ammonium hydroxide, using titanium, silicon, and oxygen as the inorganic framework elements. The catalyst involved in this patent exhibits high activity in the selective epoxidation of hydrocarbons, epoxidation of furans, desulfurization of thiophenes, and ammoxidation of ketones. It not only maintains good activity under mild reaction conditions, but its catalytic oxidation performance and stability are superior to those of pure four-coordinate titanium-silicon molecular sieves, further broadening the research and application fields of catalytic reactions in hydrocarbon epoxidation, furan epoxidation, desulfurization of thiophenes, and ammoxidation of ketones. The specific technical solutions for achieving the purpose of this invention are as follows:

[0006] This invention provides a titanium-silicon molecular sieve catalyst rich in six-coordinated titanium species, which is obtained by the following preparation method:

[0007] Step 1, Preparation of Inorganic Titanium-Silicon Molecular Sieves Precursors

[0008] An inorganic titanium-silicon molecular sieve precursor was obtained by mixing silicon source, titanium source, N,N,N-trimethyladamantyl ammonium hydroxide, hexamethyleneimine, potassium carbonate and water, followed by crystallization and calcination.

[0009] Step 2: The inorganic titanium-silicon molecular sieve precursor obtained in Step 1 is mixed with an organic quaternary ammonium hydroxide and subjected to a hydrothermal reaction to obtain the titanium-silicon molecular sieve.

[0010] Step 3: The titanium-silicon molecular sieve obtained in Step 2 is calcined to prepare a titanium-silicon molecular sieve catalyst rich in six-coordinate titanium species. A preferred method for preparing the titanium-silicon molecular sieve catalyst rich in six-coordinate titanium species is as follows:

[0011] Step 1, Preparation of Inorganic Titanium-Silicon Molecular Sieves Precursors

[0012] The preferred molar ratio of SiO2:TEOS:TMAdaOH:HMI:K2CO3:H2O is 1:(0.015~0.05):(0.01~0.045):0.3:0.035:43. The silicon source, titanium source, N,N,N-trimethyladamantyl ammonium hydroxide, organic quaternary ammonium hydroxide hexamethyleneimine, potassium carbonate, and deionized water are mixed. The preferred silicon source is fuming silica gel, and the preferred titanium source is tetrabutyl titanate.

[0013] The resulting mixture was stirred at room temperature for 2–3 hours, and then crystallized in an autoclave (where the synthesis spontaneously generates pressure) at 100–185°C; the crystallization operation was carried out in a closed system (autoclave) at 100–180°C for 3–7 days.

[0014] Preferably, the product obtained from the crystallization operation is filtered, dried, and calcined at 450-650°C for 3-10 hours to remove organic matter to obtain the inorganic titanium-silicon molecular sieve precursor. In the embodiments provided by the present invention, the molar composition of the inorganic titanium-silicon molecular sieve precursor is: (expressed in anhydrous form of oxides) TiO2:SiO2=0.01:1~0.05:1.

[0015] In step 2, the inorganic titanium-silicon molecular sieve precursor obtained in step 1 is mixed with an aqueous solution of organic quaternary ammonium hydroxide with a concentration of 0.1-10 mol / L at a weight ratio of 1:(5-50), and the mixture is subjected to a synthesis reaction in a high-pressure hydrothermal reactor at a temperature of 50-200°C (spontaneous pressure generation during synthesis) for 1-7 days to obtain the titanium-silicon molecular sieve.

[0016] Organic quaternary ammonium salts are a class of organic substances containing nitrogen (N). This embodiment involves an organic quaternary ammonium salt hydroxide. Where R is C7H 11 C8H 17 or C9H 12 Or R is C n H 2n+1 n = 1, 2, 3, 4, 5; or R = C n H 2n-1 n = 5, 6, 7, 8;

[0017] Preferably, the organic quaternary ammonium hydroxide is one of 1,3-dimethylimidazolium hydroxide, 1,3-di-tert-butylimidazolium hydroxide, 1,3-diisobutylimidazolium hydroxide, 1,3-bis(2,4,4-trimethyl-2-pentyl)imidazolium hydroxide, 1,3-dicyclopentylimidazolium hydroxide, 1,3-dicyclohexylimidazolium hydroxide, 1,3-dicycloheptylimidazolium hydroxide, and 1,3-bis(cyclohexylmethyl)imidazolium hydroxide; the cationic structural schematic diagram of the above-mentioned organic quaternary ammonium hydroxide is shown below:

[0018]

[0019] Step 3: The titanium-silicon molecular sieve obtained in Step 2 is calcined at 400-700℃ for 3-10 hours to obtain a titanium-silicon molecular sieve rich in six-coordinated titanium species.

[0020] This invention provides a method for preparing a titanium-silicon molecular sieve catalyst rich in six-coordinated titanium species, wherein the titanium-silicon molecular sieve catalyst rich in six-coordinated titanium species is prepared by any of the above methods.

[0021] The application of the titanium-silicon molecular sieve catalyst rich in six-coordinate titanium species provided by this invention is as follows: The titanium-silicon molecular sieve catalyst rich in six-coordinate titanium species is used for the epoxidation of hydrocarbons, the epoxidation of furans, the desulfurization of thiophenes, and the ammonia oxidation of ketones. Specific applications are as follows:

[0022] a. Epoxidation reaction of hydrocarbon compounds

[0023] A titanium-silicon molecular sieve catalyst rich in six-coordinate titanium species was reacted with hydrocarbon compounds, solvents and hydrogen peroxide solution at 35–90 °C for 0.5–6 hours. After filtering out the catalyst, the product was a hydrocarbon epoxide.

[0024] The hydrocarbon compounds are straight-chain olefins of propylene, allyl chloride, n-pentene, n-hexene, n-heptene, and n-octene, or cyclic olefins of cyclopentene and cyclohexene.

[0025] The solvent is an acetonitrile or methanol solution;

[0026] For propylene, the propylene pressure range for the catalytic reaction is 0.15–0.8 MPa; for other hydrocarbon compounds, the molar ratio of the hydrocarbon compound to hydrogen peroxide is 0.2–3; the weight ratio of the hydrocarbon compound to the solvent and the titanium-silicon molecular sieve catalyst rich in six-coordinate titanium species is 1:(5–15):(0.015–0.1).

[0027] b. Epoxidation reaction of furan organic compounds

[0028] The titanium-silicon molecular sieve catalyst rich in six-coordinate titanium species was reacted with furan, solvent and hydrogen peroxide solution at 35-90°C for 0.5-6 hours. After filtering out the catalyst, the product was epoxy tetrahydrofuran.

[0029] The furan-like organic compound is 2,5-dihydrofuran;

[0030] The solvent is an acetonitrile or methanol solution;

[0031] The molar ratio of furan to hydrogen peroxide is 0.2–3; the weight ratio of furan to solvent and titanium-silicon molecular sieve catalyst rich in six-coordinate titanium species is 1:5–15:0.015–0.1.

[0032] c. Desulfurization reaction

[0033] The titanium-silicon molecular sieve catalyst rich in six-coordinate titanium species was reacted with sulfur-containing compounds (simulated oil), solvent, and hydrogen peroxide at a temperature of 45–90°C for 0.5–6 hours. The product obtained after filtering out the catalyst from the reaction solution was the desulfurized product.

[0034] The sulfur-containing organic compound is thiophene;

[0035] The solvent is an acetonitrile or methanol solution;

[0036] The molar ratio of sulfur-containing compounds to hydrogen peroxide is 0.1–1; the weight ratio of sulfur-containing compounds simulating oil to solvent and titanium-silicon molecular sieve catalyst rich in six-coordinate titanium species is 1:1:0.002–0.011.

[0037] d. Ammoxidation of ketones

[0038] A titanium-silicon molecular sieve catalyst rich in six-coordinate titanium species was subjected to ammonia oxidation reaction with ketone compounds, solvent and ammonia water under heating and stirring. During the reaction, hydrogen peroxide with a concentration of 1-50 wt% was slowly added dropwise to the reaction mixture over a period of 0.5-4 hours. After the addition was completed, the reaction was continued for another 0.5-5 hours. The product obtained after filtering out the catalyst from the reaction solution was an oxime compound.

[0039] The ketone compounds are butanone and cyclohexanone;

[0040] The solvent is an aqueous solution of methanol, ethanol, tert-butanol or n-butanol, with a concentration of 5 to 50 wt%.

[0041] The molar ratio of the ketone compound to hydrogen peroxide is 0.625–2; the molar ratio of the ketone compound to ammonia is 0.7–1; the weight ratio of the ketone compound to the catalyst and solvent is 1:0.015–0.1:1–15; and the molar ratio of the ketone compound to ammonia is 1:0.1–3.

[0042] This invention provides a catalyst for the epoxidation of hydrocarbons, the epoxidation of furans, the desulfurization of thiophenes, and the ammonia oxidation of ketones. The catalyst is obtained by hydrothermal synthesis of an inorganic titanium-silicon molecular sieve precursor and an organic quaternary ammonium hydroxide.

[0043] Beneficial effects

[0044] This invention provides a titanium-silicon molecular sieve catalyst rich in six-coordinate titanium species. It is prepared by hydrothermal synthesis of an inorganic titanium-silicon molecular sieve precursor with an organic quaternary ammonium hydroxide, resulting in a catalyst with titanium, silicon, and oxygen as the inorganic framework elements. The titanium-silicon molecular sieve catalyst provided by this invention is rich in six-coordinate titanium species, with the six-coordinate titanium content accounting for 50-95% of the total titanium content. In contrast, titanium in traditional titanium-silicon molecular sieves is predominantly four-coordinate, demonstrating a significant difference from traditional titanium-silicon molecular sieve catalysts.

[0045] This invention provides a method for preparing a titanium-silicon molecular sieve catalyst rich in six-coordinated titanium species. The preparation method is simple, convenient to operate, and the reaction conditions are mild and easy to control, making it suitable for large-scale industrial production.

[0046] This invention provides the application of titanium-silicon molecular sieve catalysts rich in six-coordinate titanium species. Compared with the prior art, the catalysts provided by this invention have significantly improved catalytic activity in the epoxidation of hydrocarbons, the epoxidation of furans, the desulfurization of thiophenes, and the ammonia oxidation of ketones, further broadening the research and application fields of catalytic reactions of hydrocarbons, furans, thiophenes, and ketones. Attached Figure Description

[0047] Figure 1 The UV-Vis spectrum of the catalyst obtained in Comparative Example 1

[0048] Figures 2-9 The UV-Vis spectra of the catalysts obtained in Examples 1-8 are shown below.

[0049] Figure 10To test the conversion rate of the product of Example 11 as a function of reaction time, (a) shows the reaction using the catalyst obtained in Example 3, and (b) shows the reaction using the catalyst obtained in Comparative Example 1.

[0050] Figure 11 To test the gas chromatogram of the product of Example 1

[0051] Figure 12 Gas chromatogram of the product of Example 2 was tested.

[0052] Figure 13 To test the gas chromatogram of the product of Example 3

[0053] Figure 14 To test the gas chromatogram of the product of Example 4

[0054] Figure 15 Gas chromatogram of the product of Example 5 was tested.

[0055] Figure 16 To test the gas chromatogram of the product of Example 6

[0056] Figure 17 Gas chromatogram of the product of Example 7 was tested.

[0057] Figure 18 Gas chromatogram of the product of Example 8 was tested.

[0058] Figure 19 Gas chromatogram of the product of Example 9 was tested.

[0059] Figure 20 Gas chromatogram of the product of Example 10 was tested.

[0060] Figure 21 Gas chromatogram of the product of Example 12 was tested.

[0061] Figure 22 Specific implementation method for testing the gas chromatogram of the product of Example 13

[0062] The embodiments are merely illustrative of the present invention and are not intended to limit the scope of the present invention. All equivalent implementations of the present invention should be included within the scope of the claims of the present invention.

[0063] It should be specifically noted that the product conversion rate data in the test examples were calculated as follows:

[0064] First, we can obtain the following from the chromatogram:

[0065] A 剩余反应物 (Area of ​​remaining reactants), A 产物 (Product area), A 内标物 (Area of ​​internal standard)

[0066] The remaining reactants (n) can be obtained using the following formula. 剩余反应物 ) and products (n 产物 Molar quantity of )

[0067]

[0068] Then, there are two methods to calculate the conversion rate:

[0069] ①Use the remaining reactants (n) 剩余反应物 The conversion rate is calculated from the molar amount of ).

[0070]

[0071] ②Use the product (n) 产物 The conversion rate is calculated from the molar amount of ).

[0072]

[0073] Comparative Example 1

[0074] Ti-MWW titanium-silicon molecular sieves with MWW structures were synthesized in a sol with a SiO2 / TiO2 molar ratio of 35 according to the literature (Studies in Surface Science and Catalysis, 2007, 170, 464). Their UV-Vis spectra are attached. Figure 1 .

[0075] Example 1

[0076] 1. Preparation of titanium-silicon molecular sieve precursors

[0077] Step 1: According to the molar ratio of SiO2:TEOS:TMAdaOH:HMI:K2CO3:H2O = 1:0.05:0.01:0.3:0.035:43, fuming silica gel (gas phase SiO2), tetrabutyl titanate (TEOS, AR, Maclean), organic ammonium N,N,N-trimethyladamantyl ammonium hydroxide (TMAdaOH, AR, Leyan), organic amine hexamethyleneimine (HMI, AR, Aladdin), potassium carbonate (K2CO3, AR, Sinopharm Chemical Research), and deionized water are mixed.

[0078] The resulting mixture was stirred at room temperature for 3 hours, and then allowed to stand and crystallize for 5 days in a high-pressure autoclave (spontaneously generated pressure during synthesis);

[0079] The crystallized product was filtered, dried, and calcined at 450°C for 4 hours to remove organic matter, thus obtaining the titanium-silicon molecular sieve precursor.

[0080] 2. Preparation of titanium-silicon molecular sieve catalysts rich in six-coordinated titanium species

[0081] Step 2: The inorganic titanium-silicon molecular sieve precursor obtained in Step 1 is mixed with an aqueous solution of 1,3-dimethylimidazolium hydroxide with a concentration of 9.6 mol / L at a weight ratio of 1:48.1, and reacted in a high-pressure hydrothermal reactor at 100°C for 5 days (the synthesis spontaneously generates pressure).

[0082] Step 3: The titanium-silicon molecular sieve obtained in Step 2 is calcined at 450°C for 6 hours to obtain a titanium-silicon molecular sieve rich in six-coordinated titanium species.

[0083] Step 3 produces a titanium-silicon molecular sieve with titanium, silicon, and oxygen as framework elements and containing 91.4% hexacoordinate titanium. Its UV-Vis spectrum is shown in the appendix. Figure 2 .

[0084] Table 1: UV-Vis spectral structural data of titanium-silicon molecular sieves rich in six-coordinated titanium species

[0085]

[0086] Example 2

[0087] 1. Preparation of titanium-silicon molecular sieve precursors

[0088] Step 1: According to the molar ratio of SiO2:TEOS:TMAdaOH:HMI:K2CO3:H2O = 1:0.015:0.02:0.3:0.035:43, fuming silica gel, tetrabutyl titanate (TEOS, AR, Maclean), organic ammonium N,N,N-trimethyladamantyl ammonium hydroxide (TMAdaOH, AR, Leyan), organic amine hexamethyleneimine (HMI, AR, Aladdin), potassium carbonate (K2CO3, AR, Sinopharm Chemical Research), and deionized water are mixed.

[0089] The resulting mixture was stirred at room temperature for 3 hours, and then allowed to stand and crystallize for 7 days in a high-pressure autoclave (spontaneously generated pressure during synthesis);

[0090] The crystallized product was filtered, dried, and calcined at 550°C for 5 hours to remove organic matter, thus obtaining the titanium-silicon molecular sieve precursor.

[0091] 2. Preparation of titanium-silicon molecular sieve catalysts rich in six-coordinated titanium species

[0092] Step 2: The inorganic titanium-silicon molecular sieve precursor obtained in Step 1 is mixed with an aqueous solution of 1,3-di-tert-butylimidazolium hydroxide with a concentration of 8.5 mol / L at a weight ratio of 1:41.3, and reacted in a high-pressure hydrothermal reactor at 100°C (spontaneous pressure generation during synthesis) for 7 days.

[0093] Step 3: The titanium-silicon molecular sieve obtained in Step 2 is calcined at 550°C for 8 hours to obtain a titanium-silicon molecular sieve rich in six-coordinated titanium species.

[0094] Step 3 produces a titanium-silicon molecular sieve with titanium, silicon, and oxygen as framework elements and containing 89.4% hexacoordinate titanium. Its UV-Vis spectrum is shown in the appendix. Figure 3 .

[0095] Table 2: UV-Vis spectral structural data of titanium-silicon molecular sieves rich in six-coordinated titanium species

[0096]

[0097] Example 3

[0098] 1. Preparation of titanium-silicon molecular sieve precursors

[0099] Step 1: According to the molar ratio of SiO2:TEOS:TMAdaOH:HMI:K2CO3:H2O = 1:0.05:0.02:0.3:0.035:43, fuming silica gel, tetrabutyl titanate (TEOS, AR, Maclean), organic ammonium N,N,N-trimethyladamantyl ammonium hydroxide (TMAdaOH, AR, Leyan), organic amine hexamethyleneimine (HMI, AR, Aladdin), potassium carbonate (K2CO3, AR, Sinopharm Chemical Research), and deionized water are mixed.

[0100] The resulting mixture was stirred at room temperature for 2 hours, and then allowed to stand and crystallize for 5 days in a high-pressure autoclave (spontaneously generated pressure during synthesis);

[0101] The crystallized product was filtered, dried, and calcined at 600℃ for 8 hours to remove organic matter, thus obtaining the titanium-silicon molecular sieve precursor.

[0102] 2. Preparation of titanium-silicon molecular sieve catalysts rich in six-coordinated titanium species

[0103] Step 2: The inorganic titanium-silicon molecular sieve precursor obtained in Step 1 is mixed with an aqueous solution of 1,3-diisobutylimidazolium hydroxide with a concentration of 7.8 mol / L at a weight ratio of 1:37.1, and reacted in a high-pressure hydrothermal reactor at 135°C (spontaneous pressure generation during synthesis) for 5 days.

[0104] Step 3: The titanium-silicon molecular sieve obtained in Step 2 is calcined at 600℃ for 10 hours to obtain a titanium-silicon molecular sieve rich in six-coordinated titanium species.

[0105] Step 3 produces a titanium-silicon molecular sieve with titanium, silicon, and oxygen as framework elements and containing 87.0% hexacoordinate titanium. Its UV-Vis spectrum is shown in the appendix. Figure 4 .

[0106] Table 3: UV-Vis spectral structural data of titanium-silicon molecular sieves rich in six-coordinated titanium species

[0107]

[0108] Example 4

[0109] 1. Preparation of titanium-silicon molecular sieve precursors

[0110] Step 1: According to the molar ratio of SiO2:TEOS:TMAdaOH:HMI:K2CO3:H2O=1:0.05:0.025:0.3:0.035:43, fuming silica gel, tetrabutyl titanate (TEOS, AR, Maclean), organic ammonium N,N,N-trimethyladamantyl ammonium hydroxide (TMAdaOH, AR, Leyan), organic amine hexamethyleneimine (HMI, AR, Aladdin), potassium carbonate (K2CO3, AR, Sinopharm Chemical Research), and deionized water are mixed.

[0111] The resulting mixture was stirred at room temperature for 2 hours, and then allowed to stand and crystallize for 7 days in a high-pressure reactor (spontaneous pressure generated during synthesis) at 135°C.

[0112] The crystallized product was filtered, dried, and calcined at 650°C for 10 hours to remove organic matter, thus obtaining the titanium-silicon molecular sieve precursor.

[0113] 2. Preparation of titanium-silicon molecular sieve catalysts rich in six-coordinated titanium species

[0114] Step 2: The inorganic titanium-silicon molecular sieve precursor obtained in Step 1 is mixed with an aqueous solution of 1,3-dicyclopentylimidazolium hydroxide with a concentration of 6.9 mol / L at a weight ratio of 1:40.5, and reacted in a high-pressure hydrothermal reactor at 135°C (spontaneous pressure generation during synthesis) for 7 days.

[0115] Step 3: The titanium-silicon molecular sieve obtained in Step 2 is calcined at 650°C for 10 hours to obtain a titanium-silicon molecular sieve rich in six-coordinated titanium species.

[0116] Step 3 produces a titanium-silicon molecular sieve with titanium, silicon, and oxygen as framework elements and containing 88.4% hexacoordinate titanium. Its UV-Vis spectrum is shown in the appendix. Figure 5 .

[0117] Table 4: UV-Vis spectral structural data of titanium-silicon molecular sieves rich in six-coordinated titanium species

[0118]

[0119] Example 5

[0120] 1. Preparation of titanium-silicon molecular sieve precursors

[0121] Step 1: According to the molar ratio of SiO2:TEOS:TMAdaOH:HMI:K2CO3:H2O=1:0.05:0.03:0.3:0.035:43, fuming silica gel, tetrabutyl titanate (TEOS, AR, Maclean), organic ammonium N,N,N-trimethyladamantyl ammonium hydroxide (TMAdaOH, AR, Leyan), organic amine hexamethyleneimine (HMI, AR, Aladdin), potassium carbonate (K2CO3, AR, Sinopharm Chemical Research), and deionized water are mixed.

[0122] The resulting mixture was stirred at room temperature for 2 hours, and then allowed to stand and crystallize for 5 days in a high-pressure reactor (spontaneously generated by synthesis) at 150°C.

[0123] The crystallized product was filtered, dried, and calcined at 550°C for 6 hours to remove organic matter, thus obtaining the titanium-silicon molecular sieve precursor.

[0124] 2. Preparation of titanium-silicon molecular sieve catalysts rich in six-coordinated titanium species

[0125] Step 2: The inorganic titanium-silicon molecular sieve precursor obtained in Step 1 is mixed with an aqueous solution of 1,3-dicyclohexylimidazolium hydroxide with a concentration of 5.5 mol / L at a weight ratio of 1:36.8, and reacted in a high-pressure hydrothermal reactor at 150°C (spontaneous pressure generation during synthesis) for 5 days.

[0126] Step 3: The titanium-silicon molecular sieve obtained in Step 2 is calcined at 550°C for 6 hours to obtain a titanium-silicon molecular sieve rich in six-coordinated titanium species.

[0127] Step 3 produces a titanium-silicon molecular sieve with titanium, silicon, and oxygen as framework elements and containing 91.8% hexacoordinate titanium. Its UV-Vis spectrum is shown in the appendix. Figure 6 .

[0128] Table 5: UV-Vis spectral structural data of titanium-silicon molecular sieves rich in six-coordinated titanium species

[0129]

[0130] Example 6

[0131] 1. Preparation of titanium-silicon molecular sieve precursors

[0132] Step 1: According to the molar ratio of SiO2:TEOS:TMAdaOH:HMI:K2CO3:H2O=1:0.035:0.04:0.3:0.035:43, fuming silica gel, tetrabutyl titanate (TEOS, AR, Maclean), organic ammonium N,N,N-trimethyladamantyl ammonium hydroxide (TMAdaOH, AR, Leyan), organic amine hexamethyleneimine (HMI, AR, Aladdin), potassium carbonate (K2CO3, AR, Sinopharm Chemical Research), and deionized water are mixed.

[0133] The resulting mixture was stirred at room temperature for 3 hours, and then allowed to stand and crystallize for 3 days in a high-pressure reactor (spontaneous pressure generated during synthesis) at 150°C.

[0134] The crystallized product was filtered, dried, and calcined at 600℃ for 8 hours to remove organic matter, thus obtaining the titanium-silicon molecular sieve precursor.

[0135] 2. Preparation of titanium-silicon molecular sieve catalysts rich in six-coordinated titanium species

[0136] Step 2: The inorganic titanium-silicon molecular sieve precursor obtained in Step 1 is mixed with an aqueous solution of 1,3-dicycloheptaylimidazolium hydroxide with a concentration of 3.4 mol / L at a weight ratio of 1:31.9, and reacted in a high-pressure hydrothermal reactor at 150°C (spontaneous pressure generation during synthesis) for 3 days.

[0137] Step 3: The titanium-silicon molecular sieve obtained in Step 2 is calcined at 600℃ for 8 hours to obtain a titanium-silicon molecular sieve rich in six-coordinated titanium species.

[0138] Step 3 produces a titanium-silicon molecular sieve with titanium, silicon, and oxygen as framework elements and containing 85.0% hexacoordinate titanium. Its UV-Vis spectrum is shown in the appendix. Figure 7 .

[0139] Table 6: UV-Vis spectral structural data of titanium-silicon molecular sieves rich in six-coordinated titanium species

[0140]

[0141]

[0142] Example 7

[0143] 1. Preparation of titanium-silicon molecular sieve precursors

[0144] Step 1: According to the molar ratio of SiO2:TEOS:TMAdaOH:HMI:K2CO3:H2O = 1:0.04:0.04:0.3:0.035:43, fuming silica gel, tetrabutyl titanate (TEOS, AR, Maclean), organic ammonium N,N,N-trimethyladamantyl ammonium hydroxide (TMAdaOH, AR, Leyan), organic amine hexamethyleneimine (HMI, AR, Aladdin), potassium carbonate (K2CO3, AR, Sinopharm Chemical Research), and deionized water are mixed.

[0145] The resulting mixture was stirred at room temperature for 3 hours, and then allowed to stand and crystallize for 3 days in a high-pressure reactor (spontaneous pressure generated during synthesis) at 170°C.

[0146] The crystallized product was filtered, dried, and calcined at 550°C for 7 hours to remove organic matter, thus obtaining the titanium-silicon molecular sieve precursor.

[0147] 2. Preparation of titanium-silicon molecular sieve catalysts rich in six-coordinated titanium species

[0148] Step 2: The inorganic titanium-silicon molecular sieve precursor obtained in Step 1 is mixed with an aqueous solution of 1,3-di(cyclohexylmethyl)imidazolium hydroxide at a concentration of 1.2 mol / L at a weight ratio of 1:8.9, and reacted in a high-pressure hydrothermal reactor at 170°C (spontaneous pressure generation during synthesis) for 2 days.

[0149] Step 3: The titanium-silicon molecular sieve obtained in Step 2 is calcined at 550°C for 4 hours to obtain a titanium-silicon molecular sieve rich in six-coordinated titanium species.

[0150] Step 3 produces a titanium-silicon molecular sieve with titanium, silicon, and oxygen as framework elements and containing 84.7% hexacoordinate titanium. Its UV-Vis spectrum is shown in the appendix. Figure 8 .

[0151] Table 7: UV-Vis spectral structural data of titanium-silicon molecular sieves rich in six-coordinated titanium species

[0152]

[0153] Example 8

[0154] 1. Preparation of titanium-silicon molecular sieve precursors

[0155] Step 1: According to the molar ratio of SiO2:TEOS:TMAdaOH:HMI:K2CO3:H2O=1:0.04:0.045:0.3:0.035:43, fuming silica gel, tetrabutyl titanate (TEOS, AR, Maclean), organic ammonium N,N,N-trimethyladamantyl ammonium hydroxide (TMAdaOH, AR, Leyan), organic amine hexamethyleneimine (HMI, AR, Aladdin), potassium carbonate (K2CO3, AR, Sinopharm Chemical Research), and deionized water are mixed.

[0156] The resulting mixture was stirred at room temperature for 3 hours, and then allowed to stand and crystallize for 3 days in an autoclave (spontaneously generated pressure during synthesis) at 185°C.

[0157] The crystallized product was filtered, dried, and calcined at 650°C for 7 hours to remove organic matter, thus obtaining the titanium-silicon molecular sieve precursor.

[0158] 2. Preparation of titanium-silicon molecular sieve catalysts rich in six-coordinated titanium species

[0159] Step 2: The inorganic titanium-silicon molecular sieve precursor obtained in Step 1 is mixed with an aqueous solution of 1,3-bis(2,4,4-trimethyl-2-pentyl)imidazolium hydroxide with a concentration of 0.5 mol / L at a weight ratio of 1:5.8, and reacted in a high-pressure hydrothermal reactor at 185°C (spontaneous pressure generation during synthesis) for 1 day.

[0160] Step 3: The titanium-silicon molecular sieve obtained in Step 2 is calcined at 650°C for 7 hours to obtain a titanium-silicon molecular sieve rich in six-coordinated titanium species.

[0161] Step 3 produces a titanium-silicon molecular sieve with titanium, silicon, and oxygen as framework elements and containing 85.5% hexacoordinate titanium. Its UV-Vis spectrum is shown in the appendix. Figure 9 .

[0162] Table 8: UV-Vis spectral structural data of titanium-silicon molecular sieves rich in six-coordinated titanium species

[0163]

[0164] Test Example 1

[0165] The propylene epoxidation reaction was used as a probe reaction to characterize the catalytic activity of the titanium-silicon molecular sieve rich in six-coordinate titanium species obtained in this invention. Specific applications are as follows:

[0166] 0.025 g of the titanium-silicon molecular sieve catalyst rich in six-coordinate titanium species prepared in Example 1 was reacted with 0.45 MPa propylene, 10 g acetonitrile, and 10 mmol of 30% hydrogen peroxide at 40°C for 1 hour. After filtering out the catalyst, the product was propylene oxide. Comparative Example 1 was prepared using the same procedure to obtain its catalytic results.

[0167] The obtained propylene oxide was analyzed by gas chromatography (Agilent 8860, FID), and the detection results are as follows. Figure 11 As shown, the product yield data can be calculated from the gas chromatogram (since propylene is a gas, the product yield data is used as an indicator to evaluate the catalyst in Test Example 1), and the specific data are shown in Table 9 below:

[0168] Table 9

[0169]

[0170] The catalytic reaction evaluation in Table 9 shows that the titanium-silicon molecular sieve rich in six-coordinated titanium species prepared in this invention has significantly improved catalytic activity in the propylene epoxidation reaction.

[0171] Test Example 2

[0172] The epoxidation reaction of n-pentene was used as a probe reaction to characterize the catalytic activity of the titanium-silicon molecular sieve rich in six-coordinate titanium species obtained in this invention. Specific applications are as follows:

[0173] 0.03 g of the titanium-silicon molecular sieve catalyst rich in six-coordinate titanium species prepared in Example 10 was reacted with 0.52 g of n-pentene, 6.24 g of acetonitrile, and 15 mmol of 30% hydrogen peroxide at 50°C for 2.5 hours. After filtering out the catalyst, the product was epoxide-n-pentane. Comparative Example 1 was performed under the same conditions to obtain its catalytic results.

[0174] The obtained product, epoxide n-pentane, was analyzed by gas chromatography (Agilent 8860, FID), and the detection results are as follows: Figure 12 As shown, the product conversion rate data can be calculated based on the gas chromatogram, and the specific data are shown in Table 10 below:

[0175] Table 10

[0176]

[0177] The catalytic reaction evaluation in Table 10 shows that the titanium-silicon molecular sieve rich in hexacoordinate titanium species prepared in this invention has significantly improved catalytic activity in the epoxidation reaction of n-pentene.

[0178] Test Example 3

[0179] The hexene epoxidation reaction was used as a probe reaction to characterize the catalytic activity of the titanium-silicon molecular sieve rich in six-coordinate titanium species obtained in this invention. Specific applications are as follows:

[0180] 0.04 g of the titanium-silicon molecular sieve catalyst rich in six-coordinate titanium species prepared in Example 3 above was reacted with 0.37 g of n-hexene, 5.18 g of acetonitrile, and 20 mmol of 30% hydrogen peroxide at 60°C for 3 hours. After filtering out the catalyst, the product was epoxide hexane. Comparative Example 1 was carried out under the same procedure to obtain its catalytic results.

[0181] The obtained epoxide hexane was analyzed by gas chromatography (Agilent 8860, FID), and the detection results are as follows. Figure 13 As shown in Table 11 below, the product conversion rate can be calculated based on the gas chromatogram.

[0182] Table 11

[0183]

[0184] The catalytic reaction evaluation in Table 11 shows that the titanium-silicon molecular sieve rich in hexacoordinate titanium species prepared in this invention has significantly improved catalytic activity in the epoxidation reaction of n-hexene.

[0185] Test Example 4

[0186] The n-heptene epoxidation reaction was used as a probe reaction to characterize the catalytic activity of the titanium-silicon molecular sieve rich in six-coordinate titanium species obtained in this invention. Specific applications are as follows:

[0187] 0.015 g of the titanium-silicon molecular sieve catalyst rich in six-coordinate titanium species prepared in Example 4 above was reacted with 1.03 g of n-heptene, 9.27 g of methanol, and 5 mmol of 30% hydrogen peroxide at 65°C for 3.5 hours. After filtering out the catalyst, the product was epoxide-n-heptane. Comparative Example 1 was carried out under the same conditions to obtain its catalytic results.

[0188] The obtained epoxide heptane was analyzed by gas chromatography (Agilent 8860, FID), and the detection results are as follows. Figure 14 As shown in Table 12 below, the product conversion rate can be calculated based on the gas chromatogram.

[0189] Table 12

[0190]

[0191] The catalytic reaction evaluation in Table 12 shows that the titanium-silicon molecular sieve rich in six-coordinated titanium species prepared in this invention has significantly improved catalytic activity in the epoxidation reaction of n-heptene.

[0192] Test Example 5

[0193] The catalytic activity of the titanium-silicon molecular sieve rich in six-coordinate titanium species obtained in this invention was characterized using the n-octene epoxidation reaction as a probe reaction. Specific applications are as follows:

[0194] 0.04 g of the titanium-silicon molecular sieve catalyst rich in six-coordinate titanium species prepared in Example 5 above was reacted with 2.81 g of n-octene, 14.05 g of methanol, and 10 mmol of 30% hydrogen peroxide at 70°C for 4 hours. After filtering out the catalyst, the product was epoxide n-octane. Comparative Example 1 was carried out under the same conditions to obtain its catalytic results.

[0195] The obtained epoxide n-octane was analyzed by gas chromatography (Agilent 8860, FID), and the detection results are as follows. Figure 15 As shown, the product conversion rate data can be calculated based on the gas chromatogram, and the specific data are shown in Table 13 below:

[0196] Table 13

[0197]

[0198] The catalytic reaction evaluation in Table 13 shows that the titanium-silicon molecular sieve rich in hexacoordinate titanium species prepared in this invention has significantly improved catalytic activity in the epoxidation reaction of n-octene.

[0199] Test Example 6

[0200] The catalytic activity of the titanium-silicon molecular sieve rich in six-coordinate titanium species obtained in this invention was characterized using the cyclopentene epoxidation reaction as a probe reaction. Specific applications are as follows:

[0201] 0.06 g of the titanium-silicon molecular sieve catalyst rich in six-coordinate titanium species prepared in Example 6 above was reacted with 1.16 g of cyclopentene, 8.12 g of methanol, and 10 mmol of 30% hydrogen peroxide at 80°C for 4.5 hours. After filtering out the catalyst, the product was epoxide. Comparative Example 1 was carried out under the same conditions to obtain its catalytic results.

[0202] The obtained pentane oxide was analyzed by gas chromatography (Agilent 8860, FID), and the detection results are as follows. Figure 16 As shown, the product conversion rate data can be calculated based on the gas chromatogram, and the specific data are shown in Table 14 below:

[0203] Table 14

[0204]

[0205] The catalytic reaction evaluation in Table 14 shows that the titanium-silicon molecular sieve rich in hexacoordinate titanium species prepared in this invention has significantly enhanced catalytic activity in the epoxidation reaction of cyclopentene.

[0206] Test Example 7

[0207] The cyclohexene epoxidation reaction was used as a probe reaction to characterize the catalytic activity of the titanium-silicon molecular sieve rich in six-coordinate titanium species obtained in this invention. Specific applications are as follows:

[0208] 0.03 g of the titanium-silicon molecular sieve catalyst rich in six-coordinate titanium species prepared in Example 7 was reacted with 1.23 g of cyclohexene, 9.84 g of methanol, and 15 mmol of 30% hydrogen peroxide at 85°C for 5 hours. After filtering out the catalyst, the product was cyclohexane oxide. Comparative Example 1 was carried out under the same conditions to obtain its catalytic results.

[0209] The obtained epoxide hexane was analyzed by gas chromatography (Agilent 8860, FID), and the detection results are as follows. Figure 17 As shown, the product conversion rate data can be calculated based on the gas chromatogram, and the specific data are shown in Table 15 below:

[0210] Table 15

[0211]

[0212] The catalytic reaction evaluation in Table 15 shows that the titanium-silicon molecular sieve rich in hexacoordinate titanium species prepared in this invention has significantly improved catalytic activity in the epoxidation reaction of cyclohexene.

[0213] Test Example 8

[0214] The epoxidation reaction of allyl chloride was used as a probe reaction to characterize the catalytic activity of the titanium-silicon molecular sieve rich in six-coordinate titanium species obtained in this invention. Specific applications are as follows:

[0215] 0.03 g of the titanium-silicon molecular sieve catalyst rich in six-coordinate titanium species prepared in Example 8 was reacted with 1.61 g of allyl chloride, 8.05 g of acetonitrile, and 10 mmol of 30% hydrogen peroxide at 45°C for 2 hours. After filtering out the catalyst, the product was epichlorohydrin. Comparative Example 1 was prepared using the same procedure to obtain its catalytic results.

[0216] The epichlorohydrin obtained above was analyzed by gas chromatography (Agilent 8860, FID), and the detection results are as follows. Figure 18 As shown in Table 16 below, the product conversion rate can be calculated based on the gas chromatogram.

[0217] Table 16

[0218]

[0219] The catalytic reaction evaluation in Table 16 shows that the titanium-silicon molecular sieve rich in six-coordinate titanium species prepared in this invention has significantly enhanced catalytic activity in the epoxidation reaction of propylene chloride.

[0220] Test Example 9

[0221] The ammoniation of butanone was used as a probe reaction to demonstrate the catalytic activity of the titanium-silicon molecular sieve rich in six-coordinate titanium species obtained in this invention. Specific applications are as follows:

[0222] 0.072 g of the titanium-silicon molecular sieve catalyst rich in six-coordinate titanium species prepared in Example 1 was subjected to an ammonia oxidation reaction with 0.72 g of butanone, 7.2 g of methanol, and 0.49 g of ammonia (25% by mass). The mixture was heated and stirred until the temperature reached 60°C. 6.8 g of 5 wt% hydrogen peroxide was added dropwise over 2 hours. After the addition was complete, the reaction continued for 2.5 hours. The product obtained after filtering out the catalyst from the reaction solution was butanone oxime. Comparative Example 1 was performed using the same procedure to obtain its catalytic results.

[0223] The obtained butanone oxime was analyzed by gas chromatography (Agilent 8860, FID), and the detection results are as follows. Figure 19 As shown, the product conversion rate data can be calculated based on the gas chromatogram, and the specific data are shown in Table 17 below:

[0224] Table 17

[0225]

[0226] The catalytic reaction evaluation in Table 17 shows that the titanium-silicon molecular sieve rich in six-coordinated titanium species prepared in this invention has significantly improved catalytic activity in the ammoxidation reaction of butanone.

[0227] Test Example 10

[0228] The cyclohexanone ammoxidation reaction was used as a probe reaction to illustrate the catalytic activity of the titanium-silicon molecular sieve rich in six-coordinate titanium species obtained in this invention. Specific applications are as follows:

[0229] 0.026 g of the titanium-silicon molecular sieve catalyst rich in six-coordinate titanium species prepared in Example 2 was mixed with 1.77 g of cyclohexanone, 13.3 g of ethanol, and 2.72 g of ammonia (25% by mass) and heated and stirred for ammonia oxidation. When the temperature reached 60°C, 1.13 g of 30 wt% hydrogen peroxide was added dropwise over 3.5 hours. After the addition was complete, the reaction continued for 4 hours. The product obtained after filtering out the catalyst from the reaction solution was cyclohexanone oxime. Comparative Example 1 was performed using the same procedure to obtain its catalytic results.

[0230] The obtained cyclohexanone oxime was analyzed by gas chromatography (Agilent 8860, FID), and the detection results are as follows. Figure 20 As shown, the product conversion rate data can be calculated based on the gas chromatogram, and the specific data are shown in Table 18 below:

[0231] Table 18

[0232]

[0233] The catalytic reaction evaluation in Table 18 shows that the titanium-silicon molecular sieve rich in six-coordinated titanium species prepared in this invention exhibits significantly enhanced catalytic activity in the cyclohexanone ammoxidation reaction.

[0234] Test Example 11

[0235] The stability of the titanium-silicon molecular sieve rich in six-coordinate titanium species obtained in this invention was investigated and compared using a fixed-bed reactor and a continuous reaction with cyclohexanone ammoniation. The specific operation is as follows:

[0236] The titanium-silicon molecular sieve rich in six-coordinate titanium species prepared in Example 3 above was used as a catalyst for the fixed-bed continuous reaction of cyclohexanone ammoxidation. The catalyst dosage was 1.5 g, the reaction temperature was 76 °C, and the molar ratio of hydrogen peroxide, ammonia, and cyclohexanone was 1.1:1.7:1. The feed rate of the mixed solution of cyclohexanone and 85% tert-butanol (mass ratio 1:2.94) was 96 mL / h. Liquid samples were taken at different reaction times for analysis, and the reaction product in the solution was cyclohexanone oxime.

[0237] See appendix Figure 10 The above-mentioned cyclohexanone oxime was analyzed by gas chromatography (Agilent 8860, FID), which showed that when catalyzed by titanium silicate molecular sieves rich in six-coordinate titanium species (see attached...). Figure 10 a) The product, cyclohexanone oxime, exhibits high conversion rate, good stability, and a long reaction time. The titanium-silicon molecular sieve catalyst in Comparative Example 1 shows poor stability (see attached image). Figure 10 b) It deactivates relatively quickly.

[0238] Test Example 12

[0239] The epoxidation reaction of furan-based organic compounds was used as a probe reaction to illustrate the catalytic activity of the titanium-silicon molecular sieve rich in six-coordinate titanium species obtained in this invention. Specific applications are as follows:

[0240] 0.03 g of the titanium-silicon molecular sieve catalyst rich in six-coordinate titanium species prepared in Example 4 above was reacted with 1.61 g of 2,5-dihydrofuran, 8.05 g of acetonitrile, and 10 mmol of 30% hydrogen peroxide at 45°C for 2 hours. After filtering out the catalyst, the product was 3,4-epoxytetrahydrofuran. Comparative Example 1 was performed under the same procedure to obtain its catalytic results.

[0241] The obtained 3,4-epoxytetrahydrofuran was analyzed by gas chromatography (Agilent 8860, FID), and the detection results are as follows: Figure 21 As shown, the product conversion rate data can be calculated based on the gas chromatogram, and the specific data are shown in Table 20 below:

[0242] Table 20

[0243]

[0244] The catalytic reaction evaluation in Table 20 shows that the titanium-silicon molecular sieve rich in six-coordinated titanium species prepared in this invention has significantly improved catalytic activity in the epoxidation reaction of furan-based organic compounds.

[0245] Test Example 13

[0246] The thiophene desulfurization reaction was used as a probe reaction to illustrate the catalytic activity of the titanium-silicon molecular sieve rich in six-coordinate titanium species obtained in this invention. Specific applications are as follows:

[0247] 0.05 g of the titanium-silicon molecular sieve catalyst rich in six-coordinate titanium species prepared in Example 5 above was reacted with 7 g of thiophene-containing simulated oil (thiophene content of 1000 ug / ml), 7 g of acetonitrile, and 10 mmol of 30% hydrogen peroxide at 60°C for 3 hours. After filtering out the catalyst from the reaction solution, the product was thiophene sulfone. Comparative Example 1 was carried out under the same procedure to obtain its catalytic results.

[0248] The obtained thiophene sulfone was analyzed by gas chromatography (Agilent 8860, FID), and the detection results are as follows. Figure 22 As shown in Table 21 below, the product conversion rate data can be calculated based on the gas chromatogram.

[0249] Table 21

[0250]

[0251] The catalytic reaction evaluation in Table 21 shows that the titanium-silicon molecular sieve rich in six-coordinated titanium species prepared in this invention has significantly improved catalytic activity in the thiophene desulfurization reaction.

Claims

1. A titanium-silicon molecular sieve catalyst rich in six-coordinated titanium species, characterized in that, The titanium-silicon molecular sieve catalyst rich in six-coordinated titanium species was obtained by the following preparation method: Step 1, Preparation of Inorganic Titanium-Silicon Molecular Sieves Precursors An inorganic titanium-silicon molecular sieve precursor was obtained by mixing silicon source, titanium source, N,N,N-trimethyladamantyl ammonium hydroxide, hexamethyleneimine, potassium carbonate and water, followed by crystallization and calcination. Step 2: The inorganic titanium-silicon molecular sieve precursor obtained in Step 1 is mixed with an organic quaternary ammonium salt imidazole hydroxide and subjected to a hydrothermal reaction to obtain the titanium-silicon molecular sieve. Step 3: The titanium-silicon molecular sieve obtained in Step 2 is calcined to obtain a titanium-silicon molecular sieve catalyst rich in six-coordinated titanium species.

2. The titanium-silicon molecular sieve catalyst rich in six-coordinated titanium species as described in claim 1, characterized in that, In step 2, the Organic quaternary ammonium imidazole hydroxides are Where R is C7H 11 C8H 17 or C9H 12 ; Or R is C n H 2n+1 n = 1, 2, 3, 4, 5; Or R is C n H 2n-1 , n = 5, 6, 7, 8.

3. The titanium-silicon molecular sieve catalyst rich in six-coordinated titanium species as described in claim 1, characterized in that, In step 2, the organic quaternary ammonium salt imidazole hydroxide is one of 1,3-dimethylimidazolium hydroxide, 1,3-di-tert-butylimidazolium hydroxide, 1,3-diisobutylimidazolium hydroxide, 1,3-bis(2,4,4-trimethyl-2-pentyl)imidazolium hydroxide, 1,3-dicyclopentylimidazolium hydroxide, 1,3-dicyclohexylimidazolium hydroxide, 1,3-dicycloheptylimidazolium hydroxide, and 1,3-bis(cyclohexylmethyl)imidazolium hydroxide.

4. The titanium-silicon molecular sieve catalyst rich in six-coordinated titanium species as described in claim 1, characterized in that, In step 2, the inorganic titanium-silicon molecular sieve precursor and the organic quaternary ammonium salt imidazole hydroxide are mixed at a weight ratio of inorganic titanium-silicon molecular sieve precursor to organic quaternary ammonium salt imidazole hydroxide of 1:5 to 1:50, wherein the organic quaternary ammonium salt imidazole hydroxide is an aqueous solution with a concentration of 0.1-10 mol / L; and / or The hydrothermal reaction is carried out in a closed system at 50-200°C for 1-7 days.

5. The titanium-silicon molecular sieve catalyst rich in six-coordinated titanium species as described in claim 1, characterized in that, In step 1, the roasting treatment is to roast at 450~650℃ for 3~10 hours; and / or in step 3, the roasting treatment is to roast at 400~700℃ for 3~10 hours.

6. The titanium-silicon molecular sieve catalyst rich in six-coordinated titanium species as claimed in claim 1, characterized in that, In step 1, the silicon source, titanium source, N,N,N-trimethyladamantyl ammonium hydroxide, hexamethylene imine, potassium carbonate, and water are mixed in a molar ratio of Si:Ti:N,N,N-trimethyladamantyl ammonium hydroxide:hexamethylene imine:potassium carbonate:H₂O = 1:(0.015~0.05):(0.01~0.045):0.3:0.035:43; and / or the silicon source is fumigating silica gel; the titanium source is tetrabutyl titanate; and / or The molar composition of the inorganic titanium-silicon molecular sieve precursor is TiO2:SiO2 = 0.01:1~0.05:1; and / or the crystallization operation is to react in a closed system at 100~180℃ for 3~7 days.

7. A method for preparing a titanium-silicon molecular sieve catalyst rich in six-coordinated titanium species, characterized in that, The preparation method is as follows: Step 1, Preparation of Inorganic Titanium-Silicon Molecular Sieves Precursors An inorganic titanium-silicon molecular sieve precursor was obtained by mixing silicon source, titanium source, N,N,N-trimethyladamantyl ammonium hydroxide, hexamethyleneimine, potassium carbonate and water, followed by crystallization and calcination. Step 2: The inorganic titanium-silicon molecular sieve precursor obtained in Step 1 is mixed with an organic quaternary ammonium salt imidazole hydroxide and subjected to a hydrothermal reaction to obtain the titanium-silicon molecular sieve. Step 3: The titanium-silicon molecular sieve obtained in Step 2 is calcined to obtain a titanium-silicon molecular sieve catalyst rich in six-coordinated titanium species.

8. The application of the catalyst according to any one of claims 1 to 6 or the catalyst prepared by the method of claim 7, wherein the catalyst is used for the epoxidation reaction of hydrocarbon compounds, the epoxidation reaction of furan organic compounds, and the epoxidation reaction of thiophenes. Desulfurization of organic matter or ammonia oxidation of ketone compounds.

9. The application as described in claim 8, characterized in that, The catalyst was used for the epoxidation of propylene, allyl chloride, n-pentene, n-hexene, n-heptene, n-octene, cyclopentene, and cyclohexene. Alternatively, the catalyst can be used in the epoxidation reaction of furan; Alternatively, the catalyst can be used in the desulfurization reaction of thiophene; The catalyst may be used for the ammoxidation of butanone or cyclohexanone.

10. A catalyst for the epoxidation of hydrocarbons, the epoxidation of furans, the desulfurization of thiophenes, or the ammoxidation of ketones, characterized in that, The catalyst according to any one of claims 1 to 6 or the catalyst prepared by the method of claim 7 is obtained by synthesizing an inorganic titanium-silicon molecular sieve precursor with an organic quaternary ammonium salt imidazole hydroxide.

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