A titanium-silicon molecular sieve, its preparation method and application

Abstract

This disclosure relates to a titanium-silicon molecular sieve, its preparation method, and its application. The method includes the following steps: S1, contacting a silicon source, a titanium source, a composite template agent, and water to obtain a raw material mixture; wherein the composite template agent includes a first template agent and a second template agent; the first template agent is selected from one or more compounds having the structure shown in formula (1); the second template agent is selected from one or more compounds having the structure shown in formula (2): In formula (1), R1, R2, R3, and R4 are each independently selected from alkyl or alkenyl groups having 2 to 5 carbon atoms; in formula (2), R5, R6, and R7 are each independently selected from alkyl or alkenyl groups having 2 to 5 carbon atoms; R8 is selected from aryl groups having 6 to 12 carbon atoms; S2, subjecting the raw material mixture to a first hydrothermal crystallization treatment. This disclosure can effectively enhance the oleophilicity of the titanium-silicon molecular sieve and improve its catalytic performance.

Description

Technical Field

[0001] This application relates to the field of inorganic material preparation technology, specifically to a titanium-silicon molecular sieve, its preparation method, and its application. Background Technology

[0002] Titanium silicate molecular sieves refer to a class of heteroatom molecular sieves containing a titanium framework. Currently synthesized microporous titanium silicate molecular sieves include TS-1 (MFI structure), TS-2 (MEL structure), Ti-Beta (BEA structure), Ti-ZSM-12 (MTW structure), and Ti-MCM-22 (MWW structure), while mesoporous titanium silicate molecular sieves include Ti-MCM-41 and Ti-SBA-15. The development and application of titanium silicate molecular sieves have successfully expanded zeolite molecular sieves from the field of acid catalysis to the field of catalytic oxidation, which is of milestone significance. Among them, TS-1, first published by the Italian company Enichem in 1983, is the most representative titanium silicate molecular sieve. TS-1 has an MFI topology and a two-dimensional ten-membered ring channel system. Its

[100] direction is a straight channel with a pore size of 0.51×0.55nm, and the

[010] direction is a sinusoidal channel with a pore size of 0.53×0.56nm. Due to the introduction of Ti atoms and its unique pore structure, the oxidation system composed of TS-1 and H2O2 has advantages such as mild reaction conditions, environmentally friendly oxidation process, and good selectivity of oxidation products in the oxidation of organic matter. Currently, this catalytic oxidation system can be widely used in reactions such as alkane oxidation, olefin epoxidation, phenol hydroxylation, ketone (aldehyde) ammonium oximeation, and oil oxidative desulfurization. Industrial applications have been successively achieved in phenol hydroxylation, ketone (cyclohexanone, butanone, acetone) ammonium oximeation, and propylene epoxidation.

[0003] TS-1, a titanium-silicon molecular sieve, is currently the most widely used titanium-containing molecular sieve. With a pore size of approximately 0.56 nm, it exhibits unique confinement and shape-selective effects in the conversion of low-molecular-weight hydrocarbons. However, due to the limitation of its pore size, its conversion ability for high-molecular-weight hydrocarbons is relatively weak.

[0004] Ti-containing heteroatom molecular sieves have a large number of silanol defects inside, making them highly hydrophilic. When hydrogen peroxide aqueous solution is used as an oxidant for the reaction, they readily adsorb water molecules, forming a hydrophilic environment in the pores. This hinders the adsorption, diffusion, and reaction of organic reactants, severely affecting the catalytic performance of the molecular sieve. Summary of the Invention

[0005] The purpose of this disclosure is to provide a titanium-silicon molecular sieve, its preparation method and application, which effectively enhances the oleophilicity of the titanium-silicon molecular sieve and improves its catalytic performance.

[0006] To achieve the above objectives, the first aspect of this disclosure provides a method for preparing titanium-silicon molecular sieves, comprising the following steps:

[0007] S1. Contact the silicon source, titanium source, composite template agent, and water to obtain a raw material mixture; wherein the composite template agent includes a first template agent and a second template agent; the first template agent is selected from one or more compounds having the structure shown in formula (1); the second template agent is selected from one or more compounds having the structure shown in formula (2):

[0008]

[0009] In formula (1), R1, R2, R3 and R4 are each independently selected from alkyl groups having 2 to 5 carbon atoms or alkenyl groups having 2 to 5 carbon atoms;

[0010] In formula (2), R5, R6 and R7 are each independently selected from alkyl groups having 2 to 5 carbon atoms or alkenyl groups having 2 to 5 carbon atoms; R8 is selected from aryl groups having 6 to 12 carbon atoms.

[0011] S2. The raw material mixture is subjected to a first hydrothermal crystallization treatment.

[0012] Optionally, in the first template formula (1), R1, R2, R3 and R4 are each independently selected from an alkyl group having 3 carbon atoms or an alkenyl group having 3 carbon atoms; optionally, the first template agent is selected from one or more of tetrapropylammonium hydroxide, allyl tripropylammonium hydroxide, propenyl tripropylammonium hydroxide, butyl tripropylammonium hydroxide, 1-butenyl tripropylammonium hydroxide, 2-butenyl tripropylammonium hydroxide and 3-butenyl tripropylammonium hydroxide; preferably, it is selected from one or more of tetrapropylammonium hydroxide, allyl tripropylammonium hydroxide, propenyl tripropylammonium hydroxide, butyl tripropylammonium hydroxide and 1-butenyl tripropylammonium hydroxide;

[0013] Optionally, in the second template formula (2), R5, R6, and R7 are each independently selected from alkyl groups having 2 to 4 carbon atoms or alkenyl groups having 2 to 4 carbon atoms; R8 is selected from aryl groups having 6 to 8 carbon atoms; preferably, R5, R6, and R7 are each independently selected from alkyl groups having 3 carbon atoms or alkenyl groups having 3 carbon atoms; R8 is selected from groups having 6 to 8 carbon atoms and containing phenylene groups; optionally, the second template agent is selected from phenyltripropylammonium hydroxide, p-tolyltripropylammonium hydroxide, p-ethylphenyltripropylammonium hydroxide, benzyltripropylammonium hydroxide, phenethyltripropylammonium hydroxide, and phenylallyldipropylbenzene. The ammonium hydroxide is selected from one or more of the following: p-tolyl allyl dipropyl ammonium hydroxide, p-ethylphenyl allyl dipropyl ammonium hydroxide, benzyl allyl dipropyl ammonium hydroxide, phenethyl allyl dipropyl ammonium hydroxide, phenylpropenyl dipropyl ammonium hydroxide, p-tolyl propenyl dipropyl ammonium hydroxide, p-ethylphenyl propenyl dipropyl ammonium hydroxide, benzyl propenyl dipropyl ammonium hydroxide, and phenethyl propenyl dipropyl ammonium hydroxide; preferably, it is selected from one or more of the following: phenyltripropyl ammonium hydroxide, p-tolyl tripropyl ammonium hydroxide, phenylallyl dipropylphenyl ammonium hydroxide, benzyl allyl dipropyl ammonium hydroxide, and phenylpropenyl dipropyl ammonium hydroxide.

[0014] Optionally, the silicon source is selected from at least one of silicone grease, solid silica gel, fumed silica, and silica sol; preferably, it is selected from at least one of silicone grease, solid silica gel, and fumed silica.

[0015] Optionally, the silicone grease is selected from one or more compounds with the structure shown in formula (A) below:

[0016]

[0017] R a R b R c and R d Each is independently selected from alkyl groups having 1 to 4 carbon atoms, wherein the alkyl group is branched or straight-chain alkyl; preferably, the R a R b R c and R d Each of the following is independently selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, or tert-butyl; more preferably, the organosilicon is selected from one or more of tetramethyl silicate, tetraethyl silicate, tetrabutyl silicate, and dimethyl diethyl silyl ester; even more preferably, it is selected from one or more of tetramethyl silicate, tetraethyl silicate, and dimethyl diethyl silyl ester.

[0018] Optionally, the titanium source is selected from one or more of organic titanium sources and inorganic titanium sources;

[0019] Preferably, the organic titanium source is a titanium-containing organic ester, selected from at least one structure of the following formula (B):

[0020]

[0021] Where R e R f R g and R h Each is selected from alkyl groups having 1 to 6 carbon atoms, preferably straight-chain alkyl groups having 1 to 4 carbon atoms and branched alkyl groups having 3 to 6 carbon atoms, and more preferably R. e R f R g and R h Each is selected from straight-chain alkyl groups having 2 to 4 carbon atoms and branched alkyl groups having 2 to 4 carbon atoms; optionally, R e R f R g and R h Each of the following is selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, isopentyl, hexyl, or isohexyl; preferably, each of the following is independently selected from ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, or tert-butyl.

[0022] Preferably, the inorganic titanium source is selected from one or more of titanium chloride, nitrate or sulfate;

[0023] More preferably, the titanium source is selected from one or more of titanium tetrachloride, titanium sulfate, titanium nitrate, tetraethyl titanate, tetrapropyl titanate, and tetrabutyl titanate.

[0024] Optionally, in step S1, the molar ratio of silicon source (based on SiO2): titanium source (based on TiO2): composite template agent: water is 1:(0.001~0.040):(0.05~0.30):(5~40); preferably 1:(0.010~0.035):(0.10~0.20):(10~30).

[0025] Preferably, in the composite template agent, the molar ratio of the first template agent to the second template agent is 1:(0.01-0.10), more preferably 1:(0.02-0.08), and even more preferably 1:(0.03-0.08).

[0026] Optionally, step S1 may further include a step of hydrolyzing and removing alcohol from the raw material mixture;

[0027] Optionally, the conditions for the hydrolysis and alcohol removal treatment include: treatment at 5–120°C for 0.5–48 h; preferably treatment at 50–100°C for 1–24 h, and more preferably treatment at 60–90°C for 5–20 h.

[0028] Optionally, in step S2, the conditions for the first hydrothermal crystallization treatment include: a hydrothermal crystallization temperature of 150–200°C, a hydrothermal crystallization time of 2–168 h, and a hydrothermal crystallization pressure of self-generated pressure; preferably, the hydrothermal crystallization temperature is 160–190°C, and the hydrothermal crystallization time is 4–80 h; more preferably, the hydrothermal crystallization temperature is 165–188°C, and the hydrothermal crystallization time is 5–40 h.

[0029] Optionally, the method further includes: drying and / or calcining the crystallized product obtained from the first hydrothermal crystallization treatment to obtain a solid product;

[0030] Optionally, the drying conditions include: a drying temperature of 100–200°C and a drying time of 2–10 hours;

[0031] The conditions for the calcination treatment include: a calcination temperature of 350–650°C and a calcination time of 2–10 h; preferably, the calcination temperature is 450–550°C and the calcination time is 3–8 h.

[0032] Optionally, the method further includes: contacting the solid product with an acid solution for acid treatment, and then adding a pH adjuster for neutralization treatment to obtain an intermediate product;

[0033] Optionally, in the acid treatment, the acid is selected from one or more of hydrochloric acid, nitric acid, phosphoric acid, carbonic acid, sulfuric acid, and acetic acid; the concentration of the acid used is 0.1–1.0 mol / L, and the mass-to-volume ratio of the acid to the solid product is 80–150 g solid product / 1 L acid; optionally, the conditions for the acid treatment include: a contact temperature of 50–150°C, preferably 60–100°C, and a contact time of 0.5–5.0 h, preferably 1.0–3.5 h;

[0034] Optionally, the pH adjuster is selected from one or more alkaline solutions; the alkaline solution is selected from one or more of ammonia, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, and sodium bicarbonate, and the neutralization treatment adjusts the pH of the solution to 5-7.

[0035] Optionally, the method further includes: mixing the intermediate product with a third template agent and performing a second hydrothermal crystallization treatment;

[0036] Optionally, the mass ratio of the intermediate product to the third template agent is 2-20:1; preferably 5-15:1; the conditions for the second hydrothermal crystallization treatment include: a hydrothermal crystallization temperature of 150-200℃, a hydrothermal crystallization time of 10-40h, and a hydrothermal crystallization pressure of self-generated pressure; preferably, the hydrothermal crystallization temperature is 160-180℃ and the hydrothermal crystallization time is 20-30h.

[0037] Optionally, the third template agent is selected from one or more of tetrapropylammonium hydroxide, allyltripropylammonium hydroxide, propenyltripropylammonium hydroxide, and butyltripropylammonium hydroxide.

[0038] The second aspect of this disclosure provides a titanium-silicon molecular sieve according to the first aspect.

[0039] The third aspect of this disclosure provides a titanium-silicon molecular sieve, which has the following infrared hydroxyl spectral characteristics: the infrared hydroxyl spectrum of the titanium-silicon molecular sieve at 3200-3800 cm⁻¹... -1 The peak area obtained by normalizing the characteristic peak within the wavenumber range is denoted as I1, where I1 ranges from 1.35 to 6.55, preferably any value between 1.35 and 5.38, and more preferably any value between 3.03 and 5.05. Normalization refers to subtracting the baseline from the measured infrared hydroxyl spectrum, integrating the peak area, and dividing by the sample mass to obtain the infrared hydroxyl peak area per unit mass of sample.

[0040] Optionally, the molar ratio of silicon atoms to titanium atoms in the titanium-silicon molecular sieve is 10 to 100:1, preferably 20 to 50:1;

[0041] Optionally, the average particle size of the titanium-silicon molecular sieve particles is 0.10–0.50 μm, preferably 0.20–0.40 μm; the BET specific surface area is 400–500 m². 2 / g, preferably 430-470m 2 / g; Microporous specific surface area is 350-450m² 2 / g, preferably 380-410m 2 / g; total pore volume is 0.20–0.50 cm³. 3 / g, preferably 0.30~0.40cm 3 / g; mesopore volume is 0.03~0.30cm³ 3 / g, preferably 0.15~0.25cm 3 / g;

[0042] Optionally, the titanium-silicon molecular sieve has an AEL, AFI, AFN, BEC, CFI, CHA, CON, EUO, FAU, FER, IMF, LTA, MER, MFI, MEL, MOR, MWW, RHO, TON, *BEA, *EWT or a two-dimensional hexagonal phase structure; preferably, it has an MFI structure.

[0043] This fourth aspect of the disclosure provides the application of the titanium-silicon molecular sieves described in the second and third aspects of the disclosure in the catalytic oxidation reaction and / or adsorption separation process of organic matter.

[0044] The organic catalytic reactions include olefin epoxidation to prepare epoxides, olefin chlorohydrination to prepare chlorohydrins, aldehyde / ketone ammoniumation to prepare aldehyde / ketone oximes, and ketone Beckmann rearrangement to prepare amides;

[0045] Optionally, the organic catalytic reaction is the amination of cyclohexanone, comprising the following steps:

[0046] Under oxime reaction conditions, cyclohexanone, an oxidant, ammonia, and a catalyst are brought into contact to carry out an oxidation reaction; the catalyst comprises the titanium-silicon molecular sieve.

[0047] Optionally, the oxidant is selected from one or more of hydrogen peroxide, tert-butyl hydroperoxide, cumene hydroperoxide, and m-chloroperoxybenzoic acid; preferably, the reaction is carried out in the presence of a solvent; the solvent is selected from one or more of n-butanol, tert-butanol, ethanol, methanol, and cyclohexanol;

[0048] Preferably, the oxime reaction conditions include: a molar ratio of oxidant to cyclohexanone of 1.2–2.0:1, a molar ratio of solvent to cyclohexanone of 0.5–5:1, a molar ratio of ammonia to cyclohexanone of 1.0–3.0:1, a weight ratio of catalyst to cyclohexanone of 0.05–0.2:1; a reaction temperature of 60–90°C, and a reaction time of 0.3–1.0 h.

[0049] Through the above technical solution, this disclosure provides a titanium-silicon molecular sieve and its preparation method and application. In the preparation process of titanium-silicon molecular sieve, a first template agent with the structure shown in formula (1) and a second template agent with the structure shown in formula (2) are used as composite template agents. The synthesized titanium-silicon molecular sieve has a higher silanol content and better lipophilicity. In the catalytic oxidation reaction of organic molecules, it is beneficial to the adsorption and diffusion of organic molecules, and effectively improves the catalytic performance of titanium-silicon molecular sieve.

[0050] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0051] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings:

[0052] Figure 1 These are infrared hydroxyl graphs of the molecular sieve products obtained in Example 1 and Comparative Example 1;

[0053] Figure 2 The NMR spectroscopy of the molecular sieve products obtained in Example 1 and Comparative Example 1 is shown in the silicon NMR spectrum. 29 Si NMR);

[0054] Figure 3 These are the XRD patterns of the molecular sieves obtained in Example 1 and Comparative Example 1. Detailed Implementation

[0055] The following provides a detailed description of specific embodiments of this disclosure. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit this disclosure.

[0056] The first aspect of this disclosure provides a method for preparing titanium-silicon molecular sieves, comprising the following steps:

[0057] S1. Contact the silicon source, titanium source, composite template agent, and water to obtain a raw material mixture; wherein the composite template agent includes a first template agent and a second template agent; the first template agent is selected from one or more compounds having the structure shown in formula (1); the second template agent is selected from one or more compounds having the structure shown in formula (2):

[0058]

[0059] In formula (1), R1, R2, R3 and R4 are each independently selected from alkyl groups having 2 to 5 carbon atoms or alkenyl groups having 2 to 5 carbon atoms;

[0060] In formula (2), R5, R6 and R7 are each independently selected from alkyl groups having 2 to 5 carbon atoms or alkenyl groups having 2 to 5 carbon atoms; R8 is selected from aryl groups having 6 to 12 carbon atoms.

[0061] S2. The raw material mixture is subjected to a first hydrothermal crystallization treatment.

[0062] This disclosure provides a method for preparing titanium-silicon molecular sieves. In the preparation process of titanium-silicon molecular sieves, a first template agent having the structure shown in formula (1) and a second template agent having the structure shown in formula (2) are used as composite template agents. The synthesized titanium-silicon molecular sieves have a higher silanol content and better lipophilicity. In the catalytic oxidation reaction of organic molecules, it is beneficial to the adsorption and diffusion of organic molecules, and effectively improves the catalytic performance of titanium-silicon molecular sieves.

[0063] Through extensive experimental research, the inventors of this disclosure have discovered that, compared with conventionally used organic template agents, using the first template agent with the structure shown in formula (1) and the second template agent with the structure shown in formula (2) as a composite template agent in the preparation of titanium-silicon molecular sieves results in stronger lipophilicity of the R8 group in the second template agent structure, and stronger lipophilicity of the pore structure surface after calcination of the molecular sieve. This makes it easier to combine with lipophilic reactants during the reaction process, thereby improving the reaction efficiency.

[0064] In this disclosure, the number of carbon atoms in R1, R2, R3, R4, R5, R6, R7, and R8 refers to the total number of carbon atoms in the group. In R8 of this application, aryl refers to a group containing an aromatic group (e.g., phenyl), and the aryl group may or may not have substituents. When there are substituents, the number of carbon atoms in the aryl group is the total number of carbon atoms in the aromatic group and the substituents. For example, tolyl represents a phenyl group with a methyl group attached, and the number of carbon atoms in this group is 7.

[0065] In one specific embodiment, the alkyl group having 2 to 5 carbon atoms includes ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, and pentyl; the alkenyl group having 2 to 5 carbon atoms includes vinyl, propenyl, allyl, n-butenyl, isobutenyl, and pentenyl.

[0066] In one embodiment, in the first template formula (1), R1, R2, R3 and R4 are each independently selected from alkyl groups having 3 carbon atoms or alkenyl groups having 3 carbon atoms.

[0067] In one specific embodiment, the alkyl group having 3 carbon atoms includes n-propyl and / or isopropyl, and the alkenyl group having 3 carbon atoms includes propenyl and / or allyl.

[0068] In a preferred embodiment, the first template agent is selected from one or more of tetrapropylammonium hydroxide, allyl tripropylammonium hydroxide, propenyl tripropylammonium hydroxide, butyl tripropylammonium hydroxide, 1-butenyl tripropylammonium hydroxide, 2-butenyl tripropylammonium hydroxide, and 3-butenyl tripropylammonium hydroxide; preferably, it is selected from one or more of tetrapropylammonium hydroxide, allyl tripropylammonium hydroxide, propenyl tripropylammonium hydroxide, butyl tripropylammonium hydroxide, and 1-butenyl tripropylammonium hydroxide.

[0069] In one embodiment, in the second template formula (2), R5, R6 and R7 are each independently selected from alkyl or alkenyl groups having 2 to 4 carbon atoms; R8 is selected from aryl groups having 6 to 8 carbon atoms.

[0070] In one specific embodiment, the alkyl group having 2 to 4 carbon atoms is selected from one or more of ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, and tert-butyl; the alkenyl group having 2 to 4 carbon atoms is selected from one or more of vinyl, propenyl, allyl, n-butenyl, and isobutylenyl; and the aryl group having 6 to 8 carbon atoms is selected from one or more of phenyl, tolyl, benzyl (benzyl), ethylphenyl, phenethyl, p-tolyl, m-tolyl, o-tolyl, propenyl, n-butylphenyl, isobutylphenyl, o-ethylphenyl, p-ethylphenyl, and m-ethylphenyl.

[0071] In one embodiment, the second template agent is selected from one or more of phenyltripropylammonium hydroxide, p-tolyltripropylammonium hydroxide, p-ethylphenyltripropylammonium hydroxide, benzyltripropylammonium hydroxide, phenethyltripropylammonium hydroxide, phenylallyldipropylphenylammonium hydroxide, p-tolylallyldipropylammonium hydroxide, p-ethylphenylallyldipropylammonium hydroxide, benzylallyldipropylammonium hydroxide, phenethylallyldipropylammonium hydroxide, phenylpropenyldipropylammonium hydroxide, p-tolylpropenyldipropylammonium hydroxide, p-ethylphenylpropenyldipropylammonium hydroxide, benzylpropenyldipropylammonium hydroxide, and phenethylpropenyldipropylammonium hydroxide; preferably, it is selected from one or more of phenyltripropylammonium hydroxide, p-tolyltripropylammonium hydroxide, phenylallyldipropylphenylammonium hydroxide, benzylallyldipropylammonium hydroxide, and phenylpropenyldipropylammonium hydroxide.

[0072] In one embodiment, the silicon source is selected from at least one of silicone grease, solid silica gel, fumed silica, and silica sol; preferably, it is selected from at least one of silicone grease, solid silica gel, and fumed silica. Preferably, the solid silicon source (solid silica gel, fumed silica, and silica sol) has a SiO2 content of not less than 99.99% by weight on a dry basis, and the total mass content of Fe, Al, and Na impurities is less than 10 ppm; for example, the SiO2 content is 99.99–100% by weight, typically greater than 99.99% and less than 100% by weight. The solid silicon source can be high-purity silica gel and / or fumed silica, preferably fumed silica; wherein the high-purity silica gel preferably has a SiO2 content greater than or equal to 99.99% by weight, for example, greater than 99.99% by weight and less than 100% by weight, and the total mass content of Fe, Al, and Na impurities is less than 10 ppm. Based on the dry weight of the silica, the SiO2 content in the silica is preferably greater than or equal to 99.99% by weight, for example, 99.99% to 100% by weight, for example, greater than 99.99% by weight and less than 100% by weight; the total mass content of Fe, Al, and Na impurities in the silica is less than 10 ppm on an atomic basis; and the specific surface area of ​​the silica is between 20 and 1000 m². 2 Between / g, preferably 50-400m 2 / g.

[0073] In a preferred embodiment, the silicone grease is selected from one or more compounds with the structure shown in formula (A):

[0074]

[0075] R a R b R c and R d Each is independently selected from alkyl groups having 1 to 4 carbon atoms, wherein the alkyl group is branched or straight-chain alkyl; preferably, the R a R b R c and R d Each of the following is independently selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, or tert-butyl; more preferably, the organosilicon grease is selected from one or more of tetramethyl silicate, tetraethyl silicate, tetrabutyl silicate, and dimethyl diethyl silyl ester; even more preferably, it is selected from one or more of tetramethyl silicate, tetraethyl silicate, and dimethyl diethyl silyl ester.

[0076] In one embodiment, the titanium source is selected from one or more of organic titanium sources and inorganic titanium sources;

[0077] Preferably, the organic titanium source is a titanium-containing organic ester, selected from at least one structure of the following formula (B):

[0078]

[0079] Where R e R f R g and R h Each is selected from alkyl groups having 1 to 6 carbon atoms, preferably straight-chain alkyl groups having 1 to 4 carbon atoms and branched alkyl groups having 3 to 6 carbon atoms, and more preferably R. e R f R g and R h Each is selected from straight-chain alkyl groups having 2 to 4 carbon atoms and branched alkyl groups having 2 to 4 carbon atoms; optionally, R e R f R g and R h Each of the following is selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, isopentyl, hexyl, or isohexyl; preferably, each of the following is independently selected from ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, or tert-butyl.

[0080] Preferably, the inorganic titanium source is selected from one or more of titanium chloride, nitrate or sulfate;

[0081] More preferably, the titanium source is selected from one or more of titanium tetrachloride, titanium sulfate, titanium nitrate, tetraethyl titanate, tetrapropyl titanate, and tetrabutyl titanate.

[0082] In this disclosure, the silicon source, titanium source, first template agent, and second template agent can be purchased through ordinary commercial channels or prepared by known methods.

[0083] In one embodiment, in step S1, the molar ratio of silicon source (based on SiO2): titanium source (based on TiO2): composite template agent: water is 1:(0.001~0.040):(0.05~0.30):(5~40); preferably 1:(0.010~0.035):(0.10~0.20):(10~30). The titanium-silicon molecular sieve prepared according to the optimized raw material molar ratio in this embodiment can further improve the oleophilic and catalytic properties of the titanium-silicon molecular sieve.

[0084] In a preferred embodiment, the molar ratio of the first template agent to the second template agent in the composite template agent is 1:(0.01-0.10), preferably 1:(0.02-0.08), and more preferably 1:(0.03-0.08). Controlling the molar ratio of the first template agent and the second template agent according to this embodiment is beneficial to improving the oleophilic and catalytic properties of the titanium silicate molecular sieve.

[0085] In one specific embodiment, step S1 further includes a step of hydrolyzing and removing alcohol from the raw material mixture;

[0086] Optionally, the conditions for the hydrolysis and alcohol removal treatment include: treatment at 5–120°C for 0.5–48 h; preferably treatment at 50–100°C for 1–24 h, and more preferably treatment at 60–90°C for 5–20 h.

[0087] In one embodiment, in step S2, the conditions for the first hydrothermal crystallization treatment include: a hydrothermal crystallization temperature of 150–200°C, a hydrothermal crystallization time of 2–168 h, and a hydrothermal crystallization pressure of autogenous pressure; preferably, the hydrothermal crystallization temperature is 160–190°C, and the hydrothermal crystallization time is 4–80 h; more preferably, the hydrothermal crystallization temperature is 165–188°C, and the hydrothermal crystallization time is 5–40 h. The optimized hydrothermal crystallization treatment conditions according to this embodiment can further improve the oleophilic properties and catalytic performance of the molecular sieve.

[0088] In one specific embodiment, after step S2, the process further includes: separating the product from the first hydrothermal crystallization treatment to obtain a solid product; the separation includes one or more of centrifugation, filtration, evaporation, sedimentation, and membrane separation, and the separation can be performed according to conventional operations and conditions in the art. This also includes returning the liquid product after separating the solid product to the first step for preparing the silicon-titanium gel. The liquid product includes titanium-silicon molecular sieve nanocrystals, amorphous silicon, amorphous titanium, and a template agent. The specific liquid recycling process is a conventional operation for those skilled in the art.

[0089] In one embodiment, the method further includes: drying and / or calcining the crystallized product obtained from the first hydrothermal crystallization treatment to obtain a solid product. Drying removes most of the moisture from the molecular sieve, reducing the amount of moisture evaporating from the solid during calcination; calcination aims to remove the template agent from the molecular sieve.

[0090] In one embodiment, the drying conditions include: a drying temperature of 100–200°C and a drying time of 2–10 hours;

[0091] The conditions for the calcination treatment include: a calcination temperature of 350–650°C and a calcination time of 2–10 h; preferably, the calcination temperature is 450–550°C and the calcination time is 3–8 h.

[0092] In one embodiment, the method further includes: contacting the solid product with an acid solution for acid treatment, followed by neutralization with a pH adjuster to obtain an intermediate product. Acid treatment helps to remove amorphous structures within the molecular sieve channels.

[0093] In one embodiment, the acid solution used in the acid treatment is selected from one or more of hydrochloric acid, nitric acid, phosphoric acid, carbonic acid, sulfuric acid, and acetic acid; the concentration of the acid solution used is 0.1–1.0 mol / L, and the mass-to-volume ratio of the acid solution to the solid product is 80–150 g solid product / 1 L acid solution; optionally, the conditions for the acid treatment include: a contact temperature of 50–150°C, preferably 60–100°C, and a contact time of 0.5–5.0 h, preferably 1.0–3.5 h;

[0094] Optionally, the pH adjuster is selected from one or more alkaline solutions; the alkaline solution is selected from one or more of ammonia, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, and sodium bicarbonate, and the neutralization treatment adjusts the pH of the solution to 5-7.

[0095] In one embodiment, the method further includes: mixing the intermediate product with a third template agent and performing a second hydrothermal crystallization treatment. By subjecting the acid-treated intermediate product to a second hydrothermal crystallization treatment, a hierarchical porous structure can be prepared inside the molecular sieve, improving diffusion performance.

[0096] In one specific embodiment, the mass ratio of the intermediate product to the third template agent is 2 to 20:1; preferably 5 to 15:1.

[0097] The conditions for the second hydrothermal crystallization treatment include: a hydrothermal crystallization temperature of 150–200°C, a hydrothermal crystallization time of 10–40 h, and a hydrothermal crystallization pressure of self-generated pressure; preferably, the hydrothermal crystallization temperature is 160–180°C and the hydrothermal crystallization time is 20–30 h.

[0098] Optionally, the third template agent is selected from one or more of tetrapropylammonium hydroxide, allyltripropylammonium hydroxide, propenyltripropylammonium hydroxide, and butyltripropylammonium hydroxide.

[0099] The second aspect of this disclosure provides a titanium-silicon molecular sieve prepared according to the method described in the first aspect of this disclosure.

[0100] A third aspect of this disclosure provides a titanium-silicon molecular sieve, which has the following infrared hydroxyl spectrum characteristics:

[0101] The infrared hydroxyl spectrum of the titanium-silicon molecular sieve at 3200–3800 cm⁻¹ -1 The peak area obtained by normalizing the characteristic peaks within the wavenumber range is denoted as I1, where I1 is any value between 1.35 and 6.55, preferably any value between 1.35 and 5.38, and more preferably any value between 3.03 and 5.05. The total amount of hydroxyl groups in the titanium-silicon molecular sieve provided in this disclosure is reduced; and compared to titanium-silicon molecular sieves prepared by conventional synthesis processes, in the infrared hydroxyl spectrum of this titanium-silicon molecular sieve, the 3740 cm⁻¹... -1 and 3500cm -1 The intensity of the characteristic peaks at the specified location is reduced. In this disclosure, the intensity is 3740±10 cm⁻¹. -1 The characteristic peak at the wavenumber position represents the terminal hydroxyl group, at 3500±10 cm⁻¹. -1 The characteristic peaks at wavenumber positions represent nested hydroxyl groups. The titanium-silicon molecular sieves provided in this disclosure have fewer nested and terminal hydroxyl groups, and after normalization, the total number of hydroxyl groups is 20% to 80% of that of titanium-silicon molecular sieves synthesized by general crystallization. The normalization refers to subtracting the baseline from the measured infrared hydroxyl spectrum, integrating the peak area, and dividing by the sample mass to obtain the infrared hydroxyl peak area value per unit mass of sample.

[0102] In one specific embodiment, the infrared hydroxyl spectrum of a titanium-silicon molecular sieve (e.g., Comparative Example 1 of this disclosure) prepared using a conventional synthesis process is analyzed in the 3200–3800 cm⁻¹ region. -1 The peak area of ​​the characteristic peak within the wavenumber range is denoted as I2;

[0103] I0 is defined as any value between 20% and 80% in the following formula (S-1);

[0104] I0 = I1 / I2 (S-1);

[0105] Preferably, I0 is any value between 45% and 75%.

[0106] In a preferred embodiment, the titanium-silicon molecular sieve has the following NMR silicon spectrum characteristics: the intensity at a chemical shift of -103±1ppm in the NMR silicon spectrum of the titanium-silicon molecular sieve is denoted as Q3, and the intensity at a chemical shift of -113±1ppm in the NMR silicon spectrum of the titanium-silicon molecular sieve is denoted as Q3', and Q0, as defined in the following formula (S-2), is any value between 0.01 and 0.07;

[0107] Q0 = Q3 / Q3' (S-2).

[0108] In a preferred embodiment, Q0 is any value between 0.02 and 0.06.

[0109] In one specific embodiment, the intensity at the chemical shift of -103±1ppm in the NMR silicon spectrum of the titanium-silicon molecular sieve prepared by conventional synthesis is denoted as Q3”. Then, the Q3 / Q3”×100% of the titanium-silicon molecular sieve provided in this disclosure is 60-80%, which indicates that the titanium-silicon molecular sieve provided in this disclosure has fewer Q3 species than the titanium-silicon molecular sieve synthesized by conventional methods, indicating that the number of hydroxyl groups in the molecular sieve is less and the oleophilicity is stronger.

[0110] In one specific embodiment, the titanium-silicon molecular sieve prepared using a conventional synthesis process can be obtained by a preparation method including the following steps:

[0111] Following a molar ratio of silicon source (SiO2): titanium source (TiO2): template agent: water of 1:0.01–0.10:0.10–0.50:15–20, a solution of the traditional template agent tetrapropylammonium hydroxide (25% by weight), silicon source (TEOS), titanium source, and deionized water were stirred at 50–90°C for approximately 2–20 hours to obtain a sol. This sol was then crystallized at 150–200°C for 50–100 hours. The resulting solid was then filtered by centrifugation, washed with distilled water, dried at 90–130°C for 3–10 hours, and calcined at 500–600°C for 2–10 hours. Next, it was mixed with hydrochloric acid solution, and then neutralized with an appropriate amount of ammonia water. Finally, it was mixed with an aqueous solution of tetrapropylammonium hydroxide and hydrothermally treated at 160–180°C for 20–40 hours to obtain a traditional molecular sieve solid. The selection range of the traditional template agent is the same as that of the first template agent in the preparation method provided in this disclosure, and will not be repeated here; the selection range of the silicon source and titanium source is the same as that of the silicon source and titanium source in the preparation method provided in this disclosure, and will not be repeated here.

[0112] In one embodiment, the molar ratio of silicon atoms to titanium atoms in the titanium-silicon molecular sieve is 10 to 100:1, preferably 20 to 50:1.

[0113] In one specific embodiment, the average particle size of the titanium-silicon molecular sieve particles is 0.10–0.50 μm, preferably 0.20–0.40 μm; the BET specific surface area is 400–500 m². 2 / g, preferably 430-470m 2 / g; Microporous specific surface area is 350-450m² 2 / g, preferably 380-410m 2 / g; total pore volume is 0.20–0.50 cm³. 3 / g, preferably 0.30~0.40cm 3 / g; mesopore volume is 0.03~0.30cm³ 3 / g, preferably 0.15~0.25cm 3 / g.

[0114] In one specific embodiment, the molecular sieve may have an AEL, AFI, AFN, BEC, CFI, CHA, CON, EUO, FAU, FER, IMF, LTA, MER, MFI, MEL, MOR, MWW, RHO, TON, *BEA, *EWT or a two-dimensional hexagonal phase structure; preferably, it has an MFI structure.

[0115] Specifically, the titanium-silicon molecular sieve provided in this disclosure can be used as the catalytically active component, utilizing its unique framework elements, or it can be used as a support to further load active centers, or it can be prepared by mechanical mixing, kneading, pressing, extrusion, spray molding, spheroidizing, oil column molding, etc., with other catalysts, co-catalysts, structural additives, electronic additives, binders, inert supports, etc., using methods such as mechanical mixing, kneading molding, tableting, extrusion molding, spray molding, spheroidizing, oil column molding, etc. The reagents and preparation processes used can all be conventional reagents or processes in the art.

[0116] This fifth aspect of the disclosure provides the application of the titanium-silicon molecular sieves described in the second or third aspect of the disclosure in catalytic organic reactions and / or adsorption separation processes.

[0117] In this disclosure, the organic reactions include: catalytic oxidation reactions (olefin oxidation / epoxidation to prepare aldehydes, ketones, acids, epoxides, and vicinal diols; alkane oxidation to prepare alcohols, aldehydes, and acids; alcohol oxidation to prepare ketones and acids; aldehyde oxidation to prepare acids; aromatic hydrocarbon oxidation to prepare phenols; thioether oxidation to prepare sulfoxides and sulfones), reduction reactions, oxime reactions (aldehyde / ketone aminooxime to prepare amides and lactams), aldol condensation reactions, substitution / halogenation reactions, elimination reactions, transesterification reactions, dehydration reactions, etherification reactions, esterification reactions, double / triple bond addition reactions, diene addition reactions, Beckmann rearrangement reactions (cyclohexanone oxime gas-phase rearrangement to caprolactam), hydrogen transfer reactions, etc. The adsorption separation processes include: adsorption separation of hydrocarbons (such as ethane, ethylene, butene, and dibutene), gases (such as helium separation), and inorganic substances (such as cesium ion separation).

[0118] In one specific embodiment, the organic catalytic reaction includes olefin epoxidation to prepare epoxides, olefin chlorohydrination to prepare chlorohydrins, aldehyde / ketone ammoniumation to prepare aldehyde / ketone oximes, and ketone Beckmann rearrangement to prepare amides.

[0119] In one specific embodiment, the organic catalytic reaction is the amination of cyclohexanone, which optionally includes the following steps:

[0120] Under oxime reaction conditions, cyclohexanone, an oxidant, ammonia, and a catalyst are brought into contact to carry out an oxidation reaction; the catalyst comprises the titanium-silicon molecular sieve.

[0121] Optionally, the oxidant is selected from one or more of hydrogen peroxide, tert-butylhydrogen peroxide, cumene hydroperoxide, and m-chloroperoxybenzoic acid; preferably, the reaction is carried out in the presence of a solvent; the solvent is selected from one or more of n-butanol, tert-butanol, ethanol, methanol, and cyclohexanol;

[0122] Preferably, the oxime reaction conditions include: a molar ratio of oxidant to cyclohexanone of 1.2–2.0:1, a molar ratio of solvent to cyclohexanone of 0.5–5:1, a molar ratio of ammonia to cyclohexanone of 1.0–3.0:1, a weight ratio of catalyst to cyclohexanone of 0.05–0.2:1; a reaction temperature of 60–90°C, and a reaction time of 0.3–1.0 h.

[0123] In the applications of the titanium-silicon molecular sieve provided in this disclosure, the titanium-silicon molecular sieve or the catalyst containing the titanium-silicon molecular sieve can be used in powder form or in the form of shaped spheres, strips, cakes, granules, etc., and can be mixed with other catalysts; the applications can be carried out in various reactors such as batch reactors, slurry bed reactors, fixed bed reactors, fluidized bed reactors, moving bed reactors, and microchannel reactors; the reaction raw materials and catalysts can be fed at once, intermittently, or continuously.

[0124] Those skilled in the art will understand that the separation of products from catalysts can be achieved in various ways. For example, when using raw powdered molecular sieves as catalysts, the separation of products and the recycling and reuse of catalysts can be achieved through sedimentation, filtration, centrifugation, evaporation, membrane separation, etc. Alternatively, the catalyst can be shaped and loaded into a fixed-bed reactor, and the catalyst can be recovered after the reaction is completed. Various methods for separating and recovering catalysts are known methods.

[0125] The present disclosure is further described in detail below through examples. All raw materials used in the examples are commercially available.

[0126] The structure of the molecular sieve was determined by XRD analysis using a Siemens D5005 X-ray diffractometer. The testing methods included: Cu target, Kα radiation, Ni filter, tube voltage of 40 kV, tube current of 250 mA, scintillation counter, and a step size of 0.02°. The scanning range was 2θ = 5°–35°, and the scanning rate was 0.4° / min.

[0127] The instrument used for testing the infrared hydroxyl spectrum of molecular sieves was a Nicolet 8210 Fourier transform infrared spectrometer; the testing method included pressing the sample into a self-supporting sheet, placing it in an infrared cell, and treating the sample at 450℃ for 3 hours under 1×10-3 Pa conditions.

[0128] The instrument used for measuring the silicon NMR spectrum of the molecular sieve was a Bruker AVANCEIII 600WB NMR spectrometer; the testing methods included a resonance spectrum of 59.588MHz, a magic angle rotation speed of 3kHz, a pulse width of 1.5μs (corresponding to a 20° chamfer), a cycle delay time of 3s, and 3000 scans.

[0129] The content of template agent in molecular sieves is measured by thermogravimetric analysis. The weight loss at temperatures above 200℃ until the weight loss curve stabilizes is the content of template agent in the molecular sieve.

[0130] The chemical composition of the molecular sieve was determined by XRF analysis.

[0131] The specific surface area of ​​the molecular sieve was measured by nitrogen low-temperature adsorption-desorption method, and the micropore specific surface area was calculated by BET method; the pore volume and pore distribution were determined according to the method described in RIPP 151-90 in "Analytical Methods for Petrochemical Industry" (published by Science Press in September 1990, first edition) compiled by Yang Cuiding et al.

[0132] Unless otherwise specified, all raw materials used in the examples and comparative examples are analytical grade reagents.

[0133] Example 1

[0134] This embodiment illustrates the preparation of template-free TS-1-A using the method disclosed herein.

[0135] According to the molar ratio of silicon source (SiO2): titanium source (TiO2): composite template agent (total molar number of the two template agents): water of 1:0.03:0.20:20, a solution of tetrapropylammonium hydroxide (25 wt%) and a solution of phenyltripropylammonium hydroxide (30 wt%), tetraethyl orthosilicate (TEOS), tetrabutyl titanate [Ti(OBu)4] and deionized water were stirred at 80°C for about 8 hours to obtain a sol, wherein the molar ratio of tetrapropylammonium hydroxide (first template agent) to phenyltripropylammonium hydroxide (second template agent) was 1:0.05. Then, crystallization was carried out at 167℃ for 34 hours (first hydrothermal crystallization treatment); the solid obtained by centrifugation was filtered, washed with distilled water, dried at 100℃ for 3 hours, and calcined at 550℃ for 6 hours; then, it was mixed with 0.2 mol / L hydrochloric acid solution for acid treatment. The acid treatment conditions included: the mass-to-volume ratio of acid to the solid product was 100 g solid product / 1 L acid, the contact temperature was 75℃, the contact time was 2 hours, and after hydrochloric acid treatment, an appropriate amount of ammonia water was added to neutralize to a pH of approximately 6.5. The intermediate product obtained after acid treatment was then mixed with an aqueous solution of tetrapropylammonium hydroxide (third template agent, 25 wt%), the mass ratio of the intermediate product to the third template agent (effective mass of the template agent) was 10, and hydrothermally treated at 173℃ for 17 hours (second hydrothermal crystallization treatment) to obtain a molecular sieve solid, denoted as TS-1-A.

[0136] The XRD patterns of titanium-silicon molecular sieve TS-1-A and titanium-silicon molecular sieve D-1 prepared by Comparative Example 1 (using conventional methods) are shown below. Figure 3 As shown, by Figure 3It can be seen that the titanium-silicon molecular sieve TS-1-A prepared in this embodiment has a similar XRD curve to the titanium-silicon molecular sieve D-1 obtained in Comparative Example 1, indicating that the titanium-silicon molecular sieve prepared in this embodiment has an MFI structure.

[0137] Example 2

[0138] This embodiment illustrates the preparation of template-free TS-1-B using the method disclosed herein.

[0139] According to the molar ratio of silicon source (SiO2): titanium source (TiO2): composite template agent (total molar number of the two template agents): water of 1:0.03:0.20:20, butyl tripropylammonium hydroxide (25 wt%) solution and phenyl allyl dipropylammonium hydroxide (20 wt%) solution, tetraethyl orthosilicate (TEOS), tetrabutyl titanate [Ti(OBu)4] and deionized water were stirred at 69°C for about 12 hours to obtain a sol, wherein the molar ratio of butyl tripropylammonium hydroxide (first template agent) to phenyl allyl dipropylammonium hydroxide (second template agent) was 1:0.07. Then, crystallization was carried out at 168℃ for 29 hours. The solid obtained by centrifugation was filtered, washed with distilled water, dried at 100℃ for 3 hours, and calcined at 550℃ for 6 hours. Next, it was treated with a 0.5 mol / L hydrochloric acid solution. The acid treatment conditions included: a mass-to-volume ratio of acid to the solid product of 120 g solid product / 1 L acid, a contact temperature of 78℃, a contact time of 3 hours, and neutralization with a suitable amount of ammonia water to a pH of approximately 5.5 after hydrochloric acid treatment. The intermediate product obtained after acid treatment was then mixed with an aqueous solution of tetrapropylammonium hydroxide (third template agent, 25 wt%), with a mass ratio of intermediate product to third template agent (effective mass of template agent) of 6. The mixture was then hydrothermally treated at 167℃ for 25 hours (second hydrothermal crystallization treatment) to obtain a molecular sieve solid, denoted as TS-1-B.

[0140] Example 3

[0141] This embodiment illustrates the preparation of template-free TS-1-C using the method disclosed herein.

[0142] According to the molar ratio of silicon source (SiO2): titanium source (TiO2): composite template agent (total molar number of the two template agents): water of 1:0.03:0.15:20, a solution of tetrabutylammonium hydroxide (25 wt%) and a solution of benzyltripropylammonium hydroxide (22 wt%), tetraethyl orthosilicate (TEOS), tetrabutyl titanate [Ti(OBu)4] and deionized water were stirred at 87°C for about 16 hours to obtain a sol, wherein the molar ratio of tetrabutylammonium hydroxide (first template agent) to benzyltripropylammonium hydroxide (second template agent) was 1:0.03. Then, crystallization was carried out at 168℃ for 29 hours. The solid obtained by centrifugation was filtered, washed with distilled water, dried at 100℃ for 3 hours, and calcined at 550℃ for 6 hours. Next, it was mixed with a 1.0 mol / L hydrochloric acid solution. The acid treatment conditions included: a mass-to-volume ratio of acid to the solid product of 150 g solid product / 1 L acid, a contact temperature of 100℃, a contact time of 1.0 h, and neutralization with a suitable amount of ammonia water to approximately pH 7 after hydrochloric acid treatment. The intermediate product obtained after acid treatment was then mixed with an aqueous solution of tetrapropylammonium hydroxide (third template agent, 25 wt%), with a mass ratio of intermediate product to third template agent (effective mass of template agent) of 15. The mixture was then hydrothermally treated at 168℃ for 32 hours (second hydrothermal crystallization treatment) to obtain a molecular sieve solid, denoted as TS-1-C.

[0143] Example 4

[0144] This embodiment illustrates the preparation of template-free TS-1-D using the method disclosed herein.

[0145] According to the molar ratio of silicon source (SiO2): titanium source (TiO2): composite template agent (total molar number of the two template agents): water of 1:0.03:0.15:20, tetrapropylammonium hydroxide (25 wt%) solution and benzylpropenyl dipropylammonium hydroxide (22 wt%) solution, tetraethyl orthosilicate (TEOS), tetrabutyl titanate [Ti(OBu)4] and deionized water were stirred at 89°C for about 17 hours to obtain a sol, wherein the molar ratio of tetrabutylammonium hydroxide (first template agent) to benzyltripropylammonium hydroxide (second template agent) was 1:0.06. Then, crystallization was carried out at 183℃ for 23 hours. The solid obtained by centrifugation was filtered, washed with distilled water, dried at 100℃ for 3 hours, and calcined at 550℃ for 6 hours. Next, it was treated with a 0.1 mol / L hydrochloric acid solution. The acid treatment conditions included: a mass-to-volume ratio of acid to the solid product of 80 g solid product / 1 L acid, a contact temperature of 60℃, a contact time of 3.5 hours, and neutralization with a suitable amount of ammonia water to a pH of approximately 6.8 after hydrochloric acid treatment. The intermediate product obtained after acid treatment was then mixed with an aqueous solution of tetrapropylammonium hydroxide (third template agent, 25 wt%), with a mass ratio of intermediate product to the third template agent (effective mass of template agent) of 5. The mixture was then hydrothermally treated at 172℃ for 17 hours (second hydrothermal crystallization treatment) to obtain a molecular sieve solid, denoted as TS-1-D.

[0146] Example 5

[0147] This embodiment illustrates the preparation of template-free TS-1-E using the method disclosed herein.

[0148] According to the molar ratio of silicon source (SiO2): titanium source (TiO2): composite template agent (total molar amount of the two template agents): water of 1:0.03:0.15:20, a solution of propylene tripropylammonium hydroxide (25 wt%) and a solution of phenylethyl tripropylammonium hydroxide (26 wt%), tetraethyl orthosilicate (TEOS), tetrabutyl titanate [Ti(OBu)4] and deionized water were stirred at 75°C for about 8 hours to obtain a sol, wherein the molar ratio of propylene tripropylammonium hydroxide (first template agent) to phenylethyl tripropylammonium hydroxide (second template agent) was 1:0.08. Then, crystallization was carried out at 190℃ for 16 hours. The solid obtained by centrifugation was filtered, washed with distilled water, dried at 100℃ for 3 hours, and calcined at 550℃ for 6 hours. Next, it was treated with a 0.7 mol / L hydrochloric acid solution. The acid treatment conditions included: a mass-to-volume ratio of acid to the solid product of 140 g solid product / 1 L acid, a contact temperature of 65℃, a contact time of 2.5 hours, and neutralization with a suitable amount of ammonia water to approximately pH 7 after hydrochloric acid treatment. The intermediate product obtained after acid treatment was then mixed with an aqueous solution of tetrapropylammonium hydroxide (third template agent, 25 wt%), with a mass ratio of intermediate product to third template agent (effective mass of template agent) of 1:3. The mixture was then hydrothermally treated at 166℃ for 24 hours (second hydrothermal crystallization treatment) to obtain a molecular sieve solid, denoted as TS-1-E.

[0149] Example 6

[0150] This embodiment illustrates the preparation of template-free TS-1-F using the method disclosed herein.

[0151] A sol was prepared by mixing tetrapropylammonium hydroxide (25 wt%) solution, phenyltripropylammonium hydroxide (30 wt%) solution, tetraethyl orthosilicate (TEOS), tetrabutyl titanate [Ti(OBu)4], and deionized water at 72 °C for approximately 17 hours, with the following molar ratios: silicon source (SiO2): titanium source (TiO2): composite template agent (total molar ratio of the two template agents): water. The sol was obtained by stirring at 72 °C for approximately 17 hours, with the molar ratio of tetrapropylammonium hydroxide (first template agent) to phenyltripropylammonium hydroxide (second template agent) being 1:0.04. The sol was then crystallized at 173 °C for 12 hours. The resulting solid was then filtered by centrifugation, washed with distilled water, dried at 100 °C for 3 hours, and calcined at 550 °C for 6 hours to obtain a molecular sieve solid, denoted as TS-1-F.

[0152] Example 7

[0153] This embodiment illustrates the preparation of template-free TS-1-G using the method disclosed herein.

[0154] Following a molar ratio of silicon source (SiO2): titanium source (TiO2): composite template agent (total molar amount of both template agents): water of 1:0.03:0.20:20, a sol was obtained by stirring a 25 wt% solution of butyltripropylammonium hydroxide and a 20 wt% solution of phenylallyl dipropylammonium hydroxide, tetraethyl orthosilicate (TEOS), tetrabutyl titanate [Ti(OBu)4], and deionized water at 83 °C for approximately 8 hours. The molar ratio of butyltripropylammonium hydroxide (first template agent) to phenylallyl dipropylammonium hydroxide (second template agent) was 1:0.03. Crystallization was then carried out at 168 °C for 24 hours. The resulting solid was then filtered by centrifugation, washed with distilled water, dried at 100 °C for 3 hours, and calcined at 550 °C for 6 hours to obtain a molecular sieve solid, denoted as TS-1-G.

[0155] Example 8

[0156] This embodiment illustrates the preparation of template-free TS-1-H using the method disclosed herein.

[0157] A sol was prepared by stirring a 25% wt% tetrabutylammonium hydroxide solution and a 22% wt% benzyltripropylammonium hydroxide solution, along with tetrabutylammonium hydroxide (TEOS), tetrabutyl titanate [Ti(OBu)4], and deionized water at 95°C for approximately 22 hours. The molar ratio of tetrabutylammonium hydroxide (first template agent) to benzyltripropylammonium hydroxide (second template agent) was 1:0.07. The sol was then crystallized at 183°C for 15 hours. After centrifugation, the solid was filtered, washed with distilled water, dried at 100°C for 3 hours, and calcined at 550°C for 6 hours to obtain a molecular sieve solid, denoted as TS-1-H.

[0158] Example 9

[0159] This embodiment illustrates the preparation of template-free TS-1-I using the method disclosed herein.

[0160] A sol was prepared by stirring a 25% wt% solution of tetrapropylammonium hydroxide, a 22% wt% solution of benzylpropenyl dipropylammonium hydroxide, tetraethyl orthosilicate (TEOS), tetrabutyl titanate [Ti(OBu)4], and deionized water at 55°C for approximately 24 hours. The molar ratio of tetrapropylammonium hydroxide (first template agent) to benzylpropenyl dipropylammonium hydroxide (second template agent) was 1:0.08. The sol was then crystallized at 155°C for 13 hours. After centrifugation, the solid was filtered, washed with distilled water, dried at 100°C for 3 hours, and calcined at 550°C for 6 hours to obtain a molecular sieve solid, denoted as TS-1-I.

[0161] Example 10

[0162] This embodiment illustrates the preparation of template-free TS-1-J using the method disclosed herein.

[0163] A sol was prepared by stirring a 25% wt% solution of propylene-tripropylammonium hydroxide and a 26% wt% solution of phenylethyltripropylammonium hydroxide, along with tetraethyl orthosilicate (TEOS), tetrabutyl titanate [Ti(OBu)4], and deionized water at 93°C for approximately 1 hour. The molar ratio of propylene-tripropylammonium hydroxide (first template agent) to phenylethyltripropylammonium hydroxide (second template agent) was 1:0.08. The sol was then crystallized at 195°C for 30 hours. The resulting solid was then filtered by centrifugation, washed with distilled water, dried at 100°C for 3 hours, and calcined at 550°C for 6 hours to obtain a molecular sieve solid, denoted as TS-1-J.

[0164] Example 11

[0165] This embodiment uses a method similar to that of Example 1 to prepare the titanium-silicon molecular sieve TS-1-K. The difference from Example 1 is that the silicon source is replaced with tetramethyl silicate, the titanium source is replaced with titanium tetrachloride, the acid solution is replaced with nitric acid, and the third template agent is replaced with allyltripropylammonium hydroxide. The rest of the process is the same as in Example 1. The obtained molecular sieve solid is denoted as TS-1-K.

[0166] Example 12

[0167] This embodiment uses a method similar to that of Example 1 to prepare the titanium-silicon molecular sieve TS-1-L. The difference from Example 1 is that the second template agent is replaced with phenyltripropylammonium hydroxide, and the rest of the process is the same as in Example 1. The obtained molecular sieve solid is denoted as TS-1-L.

[0168] Example 13

[0169] This embodiment uses a similar method to Example 1 to prepare titanium-silicon molecular sieve TS-1-M, but differs from Example 1 in that:

[0170] Following a molar ratio of silicon source (SiO2): titanium source (TiO2): composite template agent (total molar amount of both template agents): water of 1:0.004:0.08:8, a sol was obtained by stirring a 25 wt% tetrapropylammonium hydroxide solution and a 30 wt% phenyltripropylammonium hydroxide solution, tetraethyl orthosilicate (TEOS), tetrabutyl titanate [Ti(OBu)4], and deionized water at 80°C for approximately 8 hours; wherein the molar ratio of tetrapropylammonium hydroxide (first template agent) to phenyltripropylammonium hydroxide (second template agent) was 1:0.1. The remaining process was the same as in Example 1, yielding a molecular sieve solid, denoted as TS-1-M.

[0171] Example 14

[0172] This embodiment uses a similar method to Example 1 to prepare titanium-silicon molecular sieve TS-1-M, but differs from Example 1 in that:

[0173] According to the molar ratio of silicon source (SiO2): titanium source (TiO2): composite template agent (total molar amount of the two template agents): water of 1:0.1:0.4:50, tetrapropylammonium hydroxide (25 wt%) solution and phenyltripropylammonium hydroxide (30 wt%) solution, tetraethyl orthosilicate (TEOS), tetrabutyl titanate [Ti(OBu)4] and deionized water were stirred at 80°C for about 8 hours to obtain a sol.

[0174] The molar ratio of tetrapropylammonium hydroxide (first template agent) to phenyltripropylammonium hydroxide (second template agent) is 1:0.5. The remaining process is the same as in Example 1, and a molecular sieve solid is obtained, denoted as TS-1-N.

[0175] Example 15

[0176] According to the molar ratio of silicon source (SiO2): titanium source (TiO2): composite template agent (total molar number of the two template agents): water of 1:0.03:0.20:20, a solution of tetrapropylammonium hydroxide (25 wt%) and a solution of phenyltripropylammonium hydroxide (30 wt%), tetraethyl orthosilicate (TEOS), tetrabutyl titanate [Ti(OBu)4] and deionized water were stirred at 80°C for about 8 hours to obtain a sol, wherein the molar ratio of tetrapropylammonium hydroxide (first template agent) to phenyltripropylammonium hydroxide (second template agent) was 1:0.05. Then, crystallization was carried out at 150℃ for 3 hours (first hydrothermal crystallization treatment); after that, the solid obtained by centrifugation was filtered, washed with distilled water, dried at 100℃ for 3 hours, and calcined at 350℃ for 10 hours; then, it was mixed with 0.2 mol / L hydrochloric acid solution for acid treatment. The acid treatment conditions included: the mass-to-volume ratio of acid solution to the solid product was 100 g solid product / 1 L acid solution, the contact temperature was 50℃, the contact time was 0.5 hours, and after hydrochloric acid treatment, an appropriate amount of ammonia water was added to neutralize to a pH of approximately 6.5. Then, the intermediate product obtained after acid treatment was mixed with an aqueous solution of tetrapropylammonium hydroxide (third template agent, 25 wt%), the mass ratio of intermediate product to third template agent (effective mass of template agent) was 2, and hydrothermally treated at 150℃ for 10 hours (second hydrothermal crystallization treatment) to obtain molecular sieve solid, denoted as TS-1-O.

[0177] Comparative Example 1

[0178] This comparative example does not add a second template agent during the preparation of titanium-silicon molecular sieves, i.e., it uses the traditional method to prepare titanium-silicon molecular sieves.

[0179] A sol was prepared by stirring a 25% (w / w) solution of tetrapropylammonium hydroxide, tetraethyl orthosilicate (TEOS), tetrabutyl titanate [Ti(OBu)4], and deionized water at 78 °C for approximately 10 hours, according to a molar ratio of silicon source (SiO2): titanium source (TiO2): template agent: water of 1:0.03:0.15:20, with the mixture being a sol. The sol was then crystallized at 178 °C for 20 hours. The resulting solid was then filtered by centrifugation, washed with distilled water, dried at 100 °C for 3 hours, and calcined at 550 °C for 6 hours. Next, it was mixed with hydrochloric acid solution, and then neutralized with an appropriate amount of ammonia water. Finally, it was mixed with an aqueous solution of tetrapropylammonium hydroxide and hydrothermally treated at 166 °C for 24 hours to obtain a molecular sieve solid, denoted as D-1.

[0180] Comparative Example 2

[0181] In this comparative example, no second template agent was added during the preparation of titanium-silicon molecular sieves, and no acid treatment or second hydrothermal crystallization treatment was performed.

[0182] Following a molar ratio of silicon source (SiO2): titanium source (TiO2): template agent: water of 1:0.03:0.20:20, a sol was prepared by stirring a 25% wt% tetrapropylammonium hydroxide solution, tetraethyl orthosilicate (TEOS), tetrabutyl titanate [Ti(OBu)4], and deionized water at 69°C for approximately 18 hours. The sol was then crystallized at 172°C for 10 hours. The resulting solid was then filtered by centrifugation, washed with distilled water, dried at 100°C for 3 hours, and calcined at 550°C for 6 hours to obtain a molecular sieve solid, denoted as D-2.

[0183] The infrared hydroxyl spectrum characteristics and nuclear magnetic resonance silicon spectrum characteristics of the molecular sieve products obtained in the above examples and comparative examples are listed in Table 1 below, and the structural parameters and other data of the molecular sieve products are listed in Table 2 below.

[0184] Wherein, I0 = (Total hydroxyl area I1 of the infrared hydroxyl spectrum of the titanium-silicon molecular sieve in Example 1 / Total hydroxyl area I2 of the infrared hydroxyl spectrum of the titanium-silicon molecular sieve in Comparative Example 1) × 100%; where the total hydroxyl area of ​​the infrared hydroxyl spectrum refers to 3200-3800 cm². -1 The sum of normalized peak areas of characteristic peaks within the range.

[0185] Q0 = (Q in the NMR spectrum of titanium-silicon molecular sieve in the example) 3 The peak area at the position of the species peak (-103 ppm) is Q3 / Q in the NMR silicon spectrum of the comparative example 1 titanium silicon molecular sieve. 3 Peak area at the species peak (-103ppm) position: Q3')×100%.

[0186] Table 1

[0187]

[0188] As can be seen from the data in Table 1 above, compared with Comparative Examples 1 and 2, the titanium-silicon molecular sieves prepared by the method provided in this disclosure show fewer terminal hydroxyl groups and hydroxyl groups in their infrared hydroxyl spectra. In contrast, the titanium-silicon molecular sieves obtained by the conventional synthesis method in Comparative Example 1 show fewer terminal hydroxyl groups in their infrared hydroxyl spectra from 3200 to 3800 cm⁻¹. -1 Characteristic peaks within the range (including 3740 cm⁻¹) -1 and 3500cm -1 Using the sum of the normalized peak areas (i2) of the characteristic peaks at the specified locations as a comparison benchmark, the infrared hydroxyl spectrum of the titanium-silicon molecular sieve prepared in the embodiments of this disclosure at 3200–3800 cm⁻¹ is compared with that of the characteristic peaks at the specified locations. -1 Characteristic peaks within the range (including 3740 cm⁻¹) -1 and 3500cm -1The sum of the normalized peak areas (characteristic peaks at the specified positions) I1 is 60-80% of that of the titanium-silicon molecular sieve obtained by the conventional synthesis method in Comparative Example 1. The infrared hydroxyl spectra of the titanium-silicon molecular sieves of Example 1 and Comparative Example 1 are shown below. Figure 1 As shown, based on the above data and Figure 1 It can be seen that the titanium-silicon molecular sieve prepared by the method provided in this disclosure has a smaller diameter than the titanium-silicon molecular sieve prepared by conventional methods (3740 cm⁻¹). -1 and 3500cm -1 The lower peak intensity and smaller peak area of ​​the characteristic peak at the location indicate that the titanium-silicon molecular sieve prepared by the method provided in this disclosure has fewer terminal hydroxyl groups and terminal hydroxyl groups, indicating that the molecular sieve provided in this disclosure has better lipophilicity, is more likely to adsorb reactants, and accelerates the reaction rate.

[0189] Furthermore, compared to Comparative Examples 1 and 2, the NMR silicon spectroscopy data of the titanium-silicon molecular sieves prepared using the method provided in this disclosure show a lower Q. 3 The species, represented by the Q in the magnetic silicon spectrum of the titanium-silicon molecular sieve obtained by conventional synthesis method in Comparative Example 1. 3 Using the peak area Q3” at the position of the species spectrum peak (-103ppm) as a reference, the Q3” in the magnetic silicon spectrum of the titanium-silicon molecular sieve prepared in this embodiment of the present disclosure is... 3 The peak area Q3 at the species peak (-103 ppm) is 60-80% of that of the titanium-silicon molecular sieve obtained by conventional synthesis method in Comparative Example 1. The magnetic silica spectra of the titanium-silicon molecular sieves of Example 1 and Comparative Example 1 are shown below. Figure 2 As shown, based on the above data and Figure 2 It can be seen that the titanium-silicon molecular sieve prepared by the method provided in this disclosure has a lower Q value compared with titanium-silicon molecular sieves prepared by conventional methods. 3 The species indicates that the molecular sieve has fewer hydroxyl groups and stronger lipophilicity.

[0190] Table 2

[0191]

[0192]

[0193] Application test cases

[0194] This test example is used to evaluate the performance of the titanium-silicon molecular sieves prepared in the comparative example and the embodiment as catalysts in the catalytic amination reaction of cyclohexanone. Specifically, the following process is included:

[0195] The cyclohexanone amination reaction was carried out in a 250 ml three-necked flask reaction apparatus equipped with an automatic temperature-controlled water bath, magnetic stirring, and reflux condenser. Samples prepared in the above examples and comparative examples were added to a three-necked flask at a ratio of 1.00 g of sample, 10 g (0.14 mol) of tert-butanol solvent, and 9.8 g (0.1 mol) of cyclohexanone (catalyst to cyclohexanone mass ratio of 0.1). The flask was then placed in a water bath at a preset reaction temperature of 80 °C. Using a peristaltic pump, 13.7 g (0.12 mol) of 30% hydrogen peroxide and 28.1 g (0.2 mol) of 25% ammonia solution were simultaneously added dropwise, with a molar ratio of cyclohexanone:ammonia:hydrogen peroxide:solvent of 1:2:1.2:1.35. The reaction was stopped after 0.5 h, rapidly cooled, and the liquid product was obtained by filtration and composition determination. The results are listed in Table 3 below.

[0196] For the long-cycle reaction, 1.00 g of the obtained sample was placed in a 100 mL slurry bed reactor equipped with continuous feed and membrane separation device. Under stirring, 30% hydrogen peroxide (mass fraction 30%) was added at a rate of 24.7 mL / h, 25% ammonia (mass fraction 25%) was added at a rate of 61.7 mL / h, and a mixture of cyclohexanone and tert-butanol (cyclohexanone to tert-butanol volume ratio 1:2) was added at a rate of 72.2 mL / h, while simultaneously being continuously discharged at the same rate. The reaction temperature was maintained at 80 °C for 120 h, and then samples were taken for analysis every 12 h. The data in the "Long-cycle Reaction Results" column of Table 3 are the average of the five sampling results after 120 h of reaction.

[0197] Cyclohexanone conversion rate (%) = (moles of cyclohexanone in the feed - moles of cyclohexanone in the product) / moles of cyclohexanone in the feed × 100%;

[0198] Cyclohexanone oxime selectivity (%) = number of moles of cyclohexanone oxime generated in the product / number of moles of cyclohexanone consumed to generate all products × 100%;

[0199] Cyclohexanone conversion rate reduction (%) = (0.5h cyclohexanone conversion rate - 120h cyclohexanone conversion rate) / 0.5h cyclohexanone conversion rate × 100%;

[0200] Cyclohexanone oxime selectivity reduction rate (%) = (0.5h cyclohexanone oxime selectivity - 120h cyclohexanone oxime selectivity) / 0.5h cyclohexanone oxime selectivity × 100%.

[0201] The reaction products were analyzed by gas chromatography, and the results were quantified using the external standard method. The chromatographic conditions were as follows: Agilent-6890 chromatograph, HP-5 capillary column, injection volume 0.5 μL, injection port temperature 280℃. Column temperature was held at 100℃ for 2 min, then increased to 250℃ at a rate of 15℃ / min and held for 10 min. An FID detector was used, with a detector temperature of 300℃.

[0202] Table 3

[0203]

[0204]

[0205] Based on the data in Tables 1 to 3 above, we can conclude that:

[0206] Comparative Example 1 did not add a second template agent during the preparation of titanium-silicon molecular sieves, and Comparative Example 2 did not add a second template agent during the preparation of titanium-silicon molecular sieves, nor did it undergo acid treatment and second hydrothermal crystallization treatment. Compared with the titanium-silicon molecular sieves D-1 to D-2 prepared by Comparative Examples 1 to 15, the titanium-silicon molecular sieves prepared by the method provided in this disclosure can obtain higher cyclohexanone conversion rate and cyclohexanone oxime selectivity in the catalytic cyclohexanone amination oxime reaction.

[0207] Compared with Examples 6-10, Examples 1-5 and 11-12 underwent acid treatment and a second hydrothermal crystallization treatment during the molecular sieve synthesis process. Compared with the titanium-silicon molecular sieves prepared in Examples 6-10, the I1 values ​​of the titanium-silicon molecular sieves prepared in Examples 1-5 and 11-12 are preferably in the range of 3.03-5.05, and the calculated I0 is in the range of 45-75%. The titanium-silicon molecular sieves prepared in Examples 1-5 and 11-12 can obtain higher cyclohexanone conversion rate and cyclohexanone oxime selectivity in the catalytic cyclohexanone amination oxime reaction.

[0208] Comparing Example 1 and Example 13, it can be seen that the amount of raw materials added in Example 1 during the synthesis of titanium-silicon molecular sieves is within the preferred range of "the molar ratio of silicon source: titanium source: composite template agent: water is 1:(0.010~0.035):(0.10~0.20):(10~30), and the molar ratio of the first template agent to the second template agent is 1:(0.03~0.08)". The amount of raw materials added in Example 13 is not within this preferred range, and the total hydroxyl area I1 of the infrared hydroxyl spectrum of the titanium-silicon molecular sieve is not in the range of 3.03~5.05. Compared with the titanium-silicon molecular sieve prepared in Example 13, the titanium-silicon molecular sieve prepared in Example 1 can obtain higher cyclohexanone conversion rate and cyclohexanone oxime selectivity in the catalytic cyclohexanone amination oxime reaction, and the reduction rate of cyclohexanone conversion rate and the reduction rate of cyclohexanone oxime selectivity under long-term reaction conditions are lower, and the stability is better.

[0209] Comparing Example 1 and Example 15, it can be seen that the preparation conditions of Example 1 are within the preferred implementation range provided in this disclosure, while those of Example 15 are not within the preferred range. Furthermore, the total hydroxyl area I1 of the infrared hydroxyl spectrum of the titanium-silicon molecular sieve is not in the range of 3.03 to 5.05. Compared with the titanium-silicon molecular sieve prepared in Example 15, the titanium-silicon molecular sieve prepared in Example 1 can obtain higher cyclohexanone conversion and cyclohexanone oxime selectivity in the catalytic cyclohexanone amination oxime reaction, and the reduction rate of cyclohexanone conversion and cyclohexanone oxime selectivity under long-term reaction conditions is lower, and the stability is better.

[0210] Diffusion test case

[0211] This test example is used to evaluate the hydrophilic and lipophilic properties of the molecular sieves prepared in the examples and comparative examples. Specifically, it includes the following steps:

[0212] The packed column in the gas chromatograph was replaced with a zero-length column filled with the sample to be tested. Nitrogen was used as the carrier gas, the flow rate was 10 mL / min, and the sample was pretreated at 200℃ for 1 h in the column oven. During the experiment, the temperature was kept constant at 200℃. A carrier gas carrying a certain concentration of cyclohexane vapor was passed through the zero-length column. When the gas chromatograph detector signal remained basically unchanged, cyclohexane reached adsorption equilibrium, and this concentration was taken as c0. Subsequently, the gas flowing through the long column was switched to pure carrier gas, and this moment was taken as t0. The diffusion curve was measured and recorded, and the diffusion coefficient of the titanium-silicon molecular sieve was obtained from the curve. The diffusion test results are listed in Table 4 below; the relative diffusion coefficients in Table 4 are compared with the diffusion coefficient of the titanium-silicon molecular sieve D-2 prepared in Comparative Example 2.

[0213] Table 4

[0214]

[0215]

[0216] As can be seen from the data in Table 4 above, the titanium-silicon molecular sieve prepared in this embodiment has a high diffusion coefficient, indicating that cyclohexane has better diffusion performance and better oleophilicity in the titanium-silicon molecular sieve prepared in this embodiment.

[0217] Compared with Examples 6-10, the titanium-silicon molecular sieves prepared in Examples 1-5 and 11-12 have higher relative diffusion coefficients, indicating that the titanium-silicon molecular sieves prepared by acid treatment and second hydrothermal crystallization treatment in the molecular sieve synthesis process have better diffusion performance and better oleophilicity.

[0218] Comparing Example 1 with Examples 13 and 15, it can be seen that the titanium-silicon molecular sieve synthesized in Example 1 according to the preferred raw material addition amount and optimized preparation conditions has a higher relative diffusion coefficient, better diffusion performance, and better oleophilicity.

[0219] The preferred embodiments of this disclosure have been described in detail above. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0220] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0221] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A method for preparing titanium-silicon molecular sieves, characterized in that, Includes the following steps: S1. Contact the silicon source, titanium source, composite template agent, and water to obtain a raw material mixture; wherein the composite template agent includes a first template agent and a second template agent; the first template agent is selected from one or more compounds having the structure shown in formula (1); the second template agent is selected from one or more compounds having the structure shown in formula (2): Equation (1); Equation (2); In formula (1), R1, R2, R3 and R4 are each independently selected from alkyl groups having 2 to 5 carbon atoms or alkenyl groups having 2 to 5 carbon atoms; In formula (2), R5, R6 and R7 are each independently selected from alkyl groups having 2 to 5 carbon atoms or alkenyl groups having 2 to 5 carbon atoms; R8 is selected from aryl groups having 6 to 12 carbon atoms; S2. Perform a first hydrothermal crystallization treatment on the raw material mixture; In step S1, the molar ratio of silicon source: titanium source: composite template agent: water is 1:(0.001~0.040):(0.05~0.30):(5~40), wherein the silicon source is calculated as SiO2 and the titanium source is calculated as TiO2; in the composite template agent, the molar ratio of the first template agent to the second template agent is 1:(0.01~0.10). In step S2, the conditions for the first hydrothermal crystallization treatment include: hydrothermal crystallization temperature of 150~200℃, hydrothermal crystallization time of 2~168h, and hydrothermal crystallization pressure of self-generated pressure.

2. The method according to claim 1, characterized in that, In the first template formula (1), R1, R2, R3 and R4 are each independently selected from alkyl groups with 3 carbon atoms or alkenyl groups with 3 carbon atoms.

3. The method according to claim 2, characterized in that, The first template agent is selected from one or more of tetrapropylammonium hydroxide, allyltripropylammonium hydroxide, propenyltripropylammonium hydroxide, butyltripropylammonium hydroxide, 1-butenyltripropylammonium hydroxide, 2-butenyltripropylammonium hydroxide, and 3-butenyltripropylammonium hydroxide.

4. The method according to claim 3, characterized in that, The first template agent is selected from one or more of tetrapropylammonium hydroxide, allyltripropylammonium hydroxide, propenyltripropylammonium hydroxide, butyltripropylammonium hydroxide and 1-butenyltripropylammonium hydroxide.

5. The method according to claim 1, characterized in that, In the second template formula (2), R5, R6 and R7 are each independently selected from alkyl or alkenyl groups with 2 to 4 carbon atoms; R8 is selected from aryl groups with 6 to 8 carbon atoms.

6. The method according to claim 5, characterized in that, R5, R6 and R7 are each independently selected from alkyl groups having 3 carbon atoms or alkenyl groups having 3 carbon atoms; R8 is selected from groups having 6 to 8 carbon atoms and containing phenylene groups.

7. The method according to claim 5, characterized in that, The second template agent is selected from one or more of the following: phenyltripropylammonium hydroxide, p-tolyltripropylammonium hydroxide, p-ethylphenyltripropylammonium hydroxide, benzyltripropylammonium hydroxide, phenethyltripropylammonium hydroxide, phenylallyldipropylphenylammonium hydroxide, p-tolylallyldipropylammonium hydroxide, p-ethylphenylallyldipropylammonium hydroxide, benzylallyldipropylammonium hydroxide, phenethylallyldipropylammonium hydroxide, phenylpropenyldipropylammonium hydroxide, p-tolylpropenyldipropylammonium hydroxide, p-ethylphenylpropenyldipropylammonium hydroxide, benzylpropenyldipropylammonium hydroxide, and phenethylpropenyldipropylammonium hydroxide.

8. The method according to claim 7, characterized in that, The second template agent is selected from one or more of phenyltripropylammonium hydroxide, p-tolyltripropylammonium hydroxide, phenylallyldipropylphenylammonium hydroxide, benzylallyldipropylammonium hydroxide, and phenylpropenyldipropylammonium hydroxide.

9. The method according to claim 1, characterized in that, The silicon source is selected from at least one of silicone grease, solid silica gel, fumed silica, and silica sol.

10. The method according to claim 9, characterized in that, The silicon source is selected from at least one of organosilicon grease, solid silica gel, and precipitated silica.

11. The method according to claim 9, characterized in that, The silicon source or the silicone grease is selected from one or more compounds with the structure shown in formula (A) below: （A）； R a R b R c and R d Each is independently selected from alkyl groups having 1 to 4 carbon atoms, wherein the alkyl group is a branched or straight-chain alkyl group.

12. The method according to claim 11, characterized in that, The R a R b R c and R d Each is independently selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, or tert-butyl.

13. The method according to claim 11, characterized in that, The silicone grease is selected from one or more of tetramethyl silicate, tetraethyl silicate, tetrabutyl silicate, and dimethyl diethyl silicate.

14. The method according to claim 13, characterized in that, The silicone grease is selected from one or more of tetramethyl silicate, tetraethyl silicate, and dimethyl diethyl silicate.

15. The method according to claim 1, characterized in that, The titanium source is selected from one or more of organic and inorganic titanium sources.

16. The method according to claim 15, characterized in that, The organotitanium source is a titanium-containing organic ester, selected from at least one of the structures shown in formula (B) below: （B）； Where R e R f R g and R h Each is selected from alkyl groups having 1 to 6 carbon atoms.

17. The method according to claim 16, characterized in that, R e R f R g and R h Each is selected from straight-chain alkyl groups having 1 to 4 carbon atoms and branched alkyl groups having 3 to 6 carbon atoms.

18. The method according to claim 17, characterized in that, R e R f R g and R h Each is selected from straight-chain alkyl groups having 2 to 4 carbon atoms and branched alkyl groups having 2 to 4 carbon atoms.

19. The method according to claim 17, characterized in that, R e R f R g and R h Each of the following is selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, isopentyl, hexyl, or isohexyl.

20. The method according to claim 19, characterized in that, R e R f R g and R h Each is independently selected from one of ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, or tert-butyl.

21. The method according to claim 15, characterized in that, The inorganic titanium source is selected from one or more of titanium chloride, nitrate or sulfate.

22. The method according to claim 15, characterized in that, The titanium source is selected from one or more of titanium tetrachloride, titanium sulfate, titanium nitrate, tetraethyl titanate, tetrapropyl titanate, and tetrabutyl titanate.

23. The method according to claim 1, characterized in that, In step S1, the molar ratio of silicon source: titanium source: composite template agent: water is 1: (0.010~0.035): (0.10~0.20): (10~30).

24. The method according to claim 1, characterized in that, In the composite template agent, the molar ratio of the first template agent to the second template agent is 1:(0.02~0.08).

25. The method according to claim 24, characterized in that, In the composite template agent, the molar ratio of the first template agent to the second template agent is 1:(0.03~0.08).

26. The method according to claim 1, characterized in that, Step S1 also includes a step of hydrolyzing and removing alcohol from the raw material mixture.

27. The method according to claim 26, characterized in that, The conditions for the hydrolysis and alcohol removal treatment include: treatment at 5~120℃ for 0.5~48h.

28. The method according to claim 27, characterized in that, The conditions for the hydrolysis and alcohol removal treatment include: treatment at 50~100℃ for 1~24h.

29. The method according to claim 28, characterized in that, The conditions for the hydrolysis and alcohol removal treatment include: treatment at 60~90℃ for 5~20h.

30. The method according to claim 1, characterized in that, In step S2, the conditions for the first hydrothermal crystallization treatment include: a hydrothermal crystallization temperature of 160~190℃ and a hydrothermal crystallization time of 4~80h.

31. The method according to claim 30, characterized in that, In step S2, the conditions for the first hydrothermal crystallization treatment include: a hydrothermal crystallization temperature of 165~188℃ and a hydrothermal crystallization time of 5~40h.

32. The method according to claim 1, characterized in that, The method further includes: drying and / or calcining the crystallized product obtained from the first hydrothermal crystallization treatment to obtain a solid product.

33. The method according to claim 32, characterized in that, The drying conditions include: a drying temperature of 100~200℃ and a drying time of 2~10h; The conditions for the calcination treatment include: a calcination temperature of 350~650℃ and a calcination time of 2~10h.

34. The method according to claim 33, characterized in that, The conditions for the calcination treatment include: a calcination temperature of 450~550℃ and a calcination time of 3~8h.

35. The method according to claim 32, characterized in that, The method further includes: contacting the solid product with an acid solution for acid treatment, and then adding a pH adjuster for neutralization treatment to obtain an intermediate product.

36. The method according to claim 35, characterized in that, In the acid treatment, the acid is selected from one or more of hydrochloric acid, nitric acid, phosphoric acid, carbonic acid, sulfuric acid, and acetic acid; the concentration of the acid used is 0.1~1.0 mol / L, and the mass-to-volume ratio of the acid to the solid product is 80~150 g solid product / 1 L acid; the conditions for the acid treatment include: a contact temperature of 50~150℃ and a contact time of 0.5~5.0 h.

37. The method according to claim 36, characterized in that, The conditions for acid treatment include: a contact temperature of 60~100℃ and a contact time of 1.0~3.5h.

38. The method according to claim 35, characterized in that, The pH adjuster is selected from one or more alkaline solutions; the alkaline solution is selected from one or more of ammonia, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, and sodium bicarbonate; the neutralization treatment adjusts the pH of the solution to 5-7.

39. The method according to claim 35, characterized in that, The method further includes: mixing the intermediate product with a third template agent and performing a second hydrothermal crystallization treatment.

40. The method according to claim 39, characterized in that, The mass ratio of the intermediate product to the third template agent is 2~20:1; the conditions for the second hydrothermal crystallization treatment include: hydrothermal crystallization temperature of 150~200℃, hydrothermal crystallization time of 10~40h, and hydrothermal crystallization pressure of self-generated pressure.

41. The method according to claim 40, characterized in that, The mass ratio of the intermediate product to the third template agent is 5~15:1; the conditions for the second hydrothermal crystallization treatment include: hydrothermal crystallization temperature of 160~180℃ and hydrothermal crystallization time of 20~30h.

42. The method according to claim 39, characterized in that, The third template agent is selected from one or more of tetrapropylammonium hydroxide, allyltripropylammonium hydroxide, propenyltripropylammonium hydroxide, and butyltripropylammonium hydroxide.

43. The titanium-silicon molecular sieve prepared by the method according to any one of claims 1 to 42.

44. The titanium-silicon molecular sieve according to claim 43, characterized in that, This titanium-silicon molecular sieve exhibits the following infrared hydroxyl spectrum characteristics: The infrared hydroxyl spectrum of the titanium-silicon molecular sieve in the 3200-3800 cm⁻¹ range was analyzed. -1 The peak area obtained by normalizing the characteristic peak within the wavenumber range is denoted as I1, where I1 is any value between 1.35 and 5.

38. The normalization refers to subtracting the baseline from the measured infrared hydroxyl spectrum, integrating the peak area, and dividing it by the sample mass to obtain the infrared hydroxyl peak area value per unit mass of sample.

45. The titanium-silicon molecular sieve according to claim 44, characterized in that, I1 is any value between 3.03 and 5.

05.

46. ​​The titanium-silicon molecular sieve according to claim 44, characterized in that, The molar ratio of silicon atoms to titanium atoms in the titanium-silicon molecular sieve is 10~100:

1.

47. The titanium-silicon molecular sieve according to claim 46, characterized in that, The molar ratio of silicon atoms to titanium atoms in the titanium-silicon molecular sieve is 20~50:

1.

48. The titanium-silicon molecular sieve according to claim 44, characterized in that, The titanium-silicon molecular sieve has an average particle size of 0.10~0.50 μm and a BET specific surface area of ​​400~500 m². 2 / g; Microporous specific surface area is 350~450m² 2 / g; total pore volume is 0.20~0.50cm³. 3 / g; mesopore volume is 0.03~0.30cm³ 3 / g.

49. The titanium-silicon molecular sieve according to claim 48, characterized in that, The titanium-silicon molecular sieve has an average particle size of 0.20~0.40 μm and a BET specific surface area of ​​430~470 m². 2 / g; Microporous specific surface area is 380~410m² 2 / g; total pore volume is 0.30~0.40cm³. 3 / g; mesopore volume is 0.15~0.25cm³ 3 / g.

50. The titanium-silicon molecular sieve according to claim 44, characterized in that, The titanium-silicon molecular sieve has AEL, AFI, AFN, BEC, CFI, CHA, CON, EUO, FAU, FER, IMF, LTA, MER, MFI, MEL, MOR, MWW, RHO, TON, *BEA, *EWT or a two-dimensional hexagonal phase structure.

51. The titanium-silicon molecular sieve according to claim 50, characterized in that; The titanium-silicon molecular sieve has an MFI structure.

52. The application of the titanium-silicon molecular sieve according to any one of claims 43 to 51 in the catalytic reaction and / or adsorption separation process of organic matter.

53. The application according to claim 52, characterized in that, The catalytic organic reactions include epoxidation of olefins to prepare epoxides, chlorohydrination of olefins to prepare chlorohydrins, ammonification of aldehydes / ketones to prepare aldehydes / ketone oximes, and Beckmann rearrangement of ketones to prepare amides.

54. The application according to claim 53, characterized in that, The organic catalytic reaction is the amination of cyclohexanone, which includes the following steps: Under oxime reaction conditions, cyclohexanone, an oxidant, ammonia, and a catalyst are brought into contact to carry out an oxidation reaction; The catalyst comprises the titanium-silicon molecular sieve.

55. The application according to claim 54, characterized in that, The oxidant is selected from one or more of hydrogen peroxide, tert-butyl hydroperoxide, cumene hydroperoxide, and m-chloroperoxybenzoic acid.

56. The application according to claim 54, characterized in that, The oxidation reaction is carried out in the presence of a solvent; the solvent is selected from one or more of n-butanol, tert-butanol, ethanol, methanol and cyclohexanol.

57. The application according to claim 54, characterized in that, The oxime reaction conditions include: a molar ratio of oxidant to cyclohexanone of 1.2 to 2.0:1, a molar ratio of solvent to cyclohexanone of 0.5 to 5:1, a molar ratio of ammonia to cyclohexanone of 1.0 to 3.0:1, and a weight ratio of catalyst to cyclohexanone of 0.05 to 0.2:1; a reaction temperature of 60 to 90°C, and a reaction time of 0.3 to 1.0 h.

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