A process for the preparation of adiponitrile

Abstract

The present disclosure relates to a method for preparing adiponitrile, comprising the following steps: contacting cyclohexanone oxime, an ammonia source and a catalyst to carry out a catalytic reaction; wherein the catalyst comprises a hierarchical porous titanium silicalite molecular sieve; the hierarchical porous titanium silicalite molecular sieve has a plurality of cavity structures in the crystal. The method does not need to use toxic and harmful solvents, and high conversion rate of cyclohexanone oxime and selectivity of adiponitrile are obtained in a heterogeneous reaction system.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of organic chemical industry, in particular to a method for preparing adiponitrile. BACKGROUND

[0002] Adiponitrile (ADN) is also known as 1,4-dicyanobutane, with the molecular formula of NC(CH3)4CN. It is a colorless transparent oily liquid, slightly bitter, hardly soluble in water, soluble in methanol, ethanol, chloroform, flammable when exposed to open flame or high heat. Adiponitrile can be added with hydrogen to generate hexamethylene diamine, which can react with adipic acid under strict material ratio to generate nylon 66 salt. Adiponitrile is an important intermediate for synthesizing nylon 66, which is the most important and valuable industrial use of adiponitrile. Research has found that hexamethylene diamine can be used to synthesize 1,6-hexamethylene diisocyanate (HDI), which is another important use of the downstream product chain of adiponitrile. Adiponitrile can also be used to prepare rubber additives, pesticides and fungicides, rocket fuel and high polymer materials, and can also be used as plasticizers, additives, colorants, textile auxiliaries and extractants for aromatic extraction.

[0003] There are three traditional production process routes for adiponitrile, namely adipic acid ammoniation method, propylene cyanide electrolytic dimerization method and butadiene cyanation method. In addition, there is a method of degrading and hydrolyzing caprolactam, but this method has not been reported for large-scale industrialization. The adipic acid ammoniation method is divided into gas phase method and liquid phase method, and the liquid phase method is divided into batch method and continuous method. This process has a long process flow, poor product quality, more impurities and low yield. The propylene cyanide electrolytic dimerization method can be divided into two types: membrane-free electrolysis and membrane electrolysis. This process has small pollution, short process flow and low investment. However, due to the high toxicity and strong corrosion of propylene cyanide, as well as the high price of propylene cyanide and high electrolytic energy consumption, it is difficult to mass-produce and has small profit space. The butadiene cyanation method is divided into chlorinated cyanation method and direct cyanation method. The direct butadiene cyanation method has a short process route, low investment, low raw material cost, small pollution, high product yield and good quality. However, the use of hydrocyanic acid makes the process highly toxic. SUMMARY

[0004] The purpose of the present disclosure is to provide a method for preparing adiponitrile, which does not require the use of toxic and harmful solvents, and can obtain high cyclohexanone oxime conversion rate and adiponitrile selectivity in a heterogeneous reaction system.

[0005] In order to achieve the above purpose, the present disclosure provides a method for preparing adiponitrile, comprising the following steps:

[0006] contacting cyclohexanone oxime, an ammonia source and a catalyst for catalytic reaction;

[0007] The catalyst comprises a hierarchical pore titanium silicalite molecular sieve, and the hierarchical pore titanium silicalite molecular sieve has a plurality of cavity structures in the crystal.

[0008] Optionally, the method further comprises:

[0009] contacting cyclohexanone oxime, an ammonia source and a catalyst in the presence of a solvent to perform an intramolecular rearrangement and ring-opening cyano reaction;

[0010] Optionally, the solvent is selected from one or more of methanol, ethanol, propanol, butanol and cyclohexanol; the ammonia source is selected from aqueous ammonia or ammonia gas; preferably, the ammonia source is selected from aqueous ammonia with a concentration of 25-30 wt.%;

[0011] Preferably, the molar ratio of cyclohexanone oxime to solvent is 1:(3-100), preferably 1:(10-50); the weight ratio of ammonia source to solvent, calculated as pure ammonia, is 1:(10-1000), preferably 1:(20-500).

[0012] Optionally, the conditions of the catalytic reaction include: a reaction temperature of 200-450°C, preferably 350-400°C; a reaction time of 1-72h, preferably 10-24h; a reaction pressure of 0.1-3MPa, preferably 0.1-2MPa; a weight hourly space velocity of cyclohexanone oxime of 0.1-25h -1 , preferably 0.5-12h -1 ;

[0013] Optionally, the reactor for the catalytic reaction is selected from any one of a fixed bed reactor, a tank reactor, a moving bed reactor, a suspended bed reactor or a slurry bed reactor.

[0014] Optionally, the size of the single cavity structure of the hierarchical pore titanosilicate molecular sieve is 2-50nm, preferably 5-40nm;

[0015] Preferably, the volume of all the cavity structures accounts for 10-50%, further preferably 15-45%, of the total volume of the molecular sieve.

[0016] Optionally, the shape of the cavity structure is selected from one or more of a sphere, a cube, an ellipsoid and an irregular cube.

[0017] Optionally, the hierarchical pore titanosilicate molecular sieve has the following 31 P MAS NMR characteristics:

[0018] The peak intensity of the characteristic peak at a chemical shift of -6±1ppm of the hierarchical pore titanosilicate molecular sieve is denoted as N1; the peak intensity of the characteristic peak at a chemical shift of -34±1ppm of the hierarchical pore titanosilicate molecular sieve is denoted as N2; the peak intensity of the characteristic peak at a chemical shift of -61±1ppm of the hierarchical pore titanosilicate molecular sieve is denoted as N3;

[0019] X as defined in the following formula (1-1) 1-1is any value between 0.15 and 0.30;

[0020] X 1-1 = N1 / N3 Formula (1-1); and

[0021] X as defined by the following Formula (1-2) 1-2 is any value between 0.10 and 0.25;

[0022] X 1-2 = N2 / N3 Formula (1-2);

[0023] Preferably, the X 1-1 is any value between 0.18 and 0.29; the X 1-2 is any value between 0.12 and 0.20.

[0024] Optionally, the multi-level porous titanosilicate molecular sieve has the following 29 Si MAS NMR characteristics:

[0025] The peak area of the spectrum peak at the position of -103 ± 1 ppm of the framework heteroatom molecular sieve chemical shift is denoted as Q 3 ; the peak area of the spectrum peak at the position of -113 ± 1 ppm of the framework heteroatom molecular sieve chemical shift is denoted as Q 4-1 ; and the peak area of the spectrum peak at the position of -116 ± 1 ppm of the framework heteroatom molecular sieve chemical shift is denoted as Q 4-2 ;

[0026] X as defined by the following Formula (2-1) 2-1 is any value between 0.04 and 0.45:

[0027] X 2-1 = Q 3 / Q 4-1 Formula (2-1);

[0028] X as defined by the following Formula (2-2) 2-2 is any value between 0.15 and 0.65:

[0029] X 2-2 = Q 3 / Q 4-2 Formula (2-2);

[0030] Preferably, the X 2-1 is any value between 0.08 and 0.28, and the X 2-2 is any value between 0.25 and 0.48.

[0031] Optionally, the multi-level porous titanosilicate molecular sieve has the following 1 H MAS NMR characteristics:

[0032] The peak area of the peak at the chemical shift of 1.8 ± 0.1 ppm is denoted as A1, the peak area of the peak at the chemical shift of 2.2 ± 0.1 ppm is denoted as A2, the peak area of the peak at the chemical shift of 2.8 ± 0.1 ppm is denoted as A3, the peak area of the peak at the chemical shift of 3.8 ± 0.1 ppm is denoted as A4, and the peak area of the peak at the chemical shift of 4.6 ± 0.1 ppm is denoted as A5;

[0033] X3 defined by the following formula (3) is any value between 0.1 and 1.2:

[0034] X3 = A1 / (A2 + A3 + A4 + A5) formula (3);

[0035] Preferably, X3 is any value between 0.2 and 0.9.

[0036] Optionally, the molar ratio of silicon atoms to titanium atoms in the multi-level pore titanosilicate molecular sieve is (10-100): 1, preferably (15-80): 1.

[0037] Optionally, the multi-level pore titanosilicate molecular sieve is selected from one or more of MFI structure molecular sieve, MEL structure molecular sieve, BEA structure molecular sieve, MWW structure molecular sieve, two-dimensional hexagonal structure molecular sieve, MOR structure molecular sieve, and TUN structure molecular sieve; preferably selected from one or more of MFI structure molecular sieve, MEL structure molecular sieve, BEA structure molecular sieve, MCM structure molecular sieve, and SBA structure molecular sieve; further preferably one or more of MFI structure molecular sieve, MEL structure molecular sieve, and BEA structure molecular sieve.

[0038] Optionally, the multi-level pore titanosilicate molecular sieve comprises molecular sieve particles composed of a single crystal grain, and / or molecular sieve particles composed of a plurality of crystal grains aggregated together.

[0039] Optionally, the average particle size of the molecular sieve particles is 0.1-0.8 μm, preferably 0.15-0.65 μm; the BET specific surface area is 250-650 m 2 / g, preferably 280-600 m 2 / g; the micropore specific surface area is 280-550 m 2 / g, preferably 300-500 m 2 / g; the total pore volume is 0.2-0.55 cm 3 / g, preferably 0.25-0.50 cm 3 / g; the mesopore volume is 0.1-0.4 cm 3 / g, preferably 0.15-0.35 cm 3 / g;

[0040] Optionally, the multi-level pore titanosilicate molecular sieve has a hysteresis loop between the adsorption isotherm and the desorption isotherm of the low-temperature nitrogen adsorption; preferably, the starting relative pressure (P / P0) at which the hysteresis loop occurs is 0.3-0.55.

[0041] Optionally, the multi-level pore titanosilicate molecular sieve is prepared by a preparation method comprising the following steps:

[0042] S1, mixing a titanium source, a silicon source, a first template agent, water, a silylation reagent and a structure filler to obtain a reaction mixture;

[0043] S2, sequentially performing a first hydrothermal crystallization treatment and a first calcination treatment on the reaction mixture to obtain a molecular sieve intermediate;

[0044] S3, mixing the molecular sieve intermediate, a second template agent and water, and then sequentially performing a second hydrothermal crystallization treatment and a second calcination treatment.

[0045] Optionally, in step S1, the molar ratio of the titanium source: the silicon source: the first template agent: water: the silylation reagent is (0.002-0.15):1:(0.01-4):(1-50):(0.02-0.35); preferably (0.01-0.06):1:(0.02-1.5):(10-30):(0.03-0.15); and the weight ratio of SiO2 to the structure filler in the reaction mixture is (5-50):1, preferably (8-30):1.

[0046] Optionally, in step S1, the silicon source is selected from at least one of organic silicon grease, solid silica gel, white carbon black and silica sol; preferably, it is selected from at least one of organic silicon grease, solid silica gel and white carbon black;

[0047] Further preferably, the organic silicon grease has a general structure as shown in the following formula (A):

[0048]

[0049] wherein R a , R b , R c , R d are each independently selected from an alkyl group having 1-6 carbon atoms, which is a branched or straight-chain alkyl group; preferably, R a , R b , R c , R d are each independently selected from a straight-chain alkyl group having 1-4 carbon atoms or a branched alkyl group having 3-4 carbon atoms; further preferably, the R a , R b , R cR1, R2, R3and R4are each independently selected from one or more of a linear alkyl group having 1 to 4 carbon atoms and a branched alkyl group having 3 to 4 carbon atoms, further preferably R1, R2, R3and R4are each independently selected from one or more of a methyl group, an ethyl group, a n-propyl group, an iso-propyl group, a n-butyl group, a sec-butyl group, an iso-butyl group and a tert-butyl group; d R1, R2, R3and R4are each independently selected from one or more of a linear alkyl group having 1 to 4 carbon atoms and a branched alkyl group having 3 to 4 carbon atoms, further preferably R1, R2, R3and R4are each independently selected from one or more of a methyl group, an ethyl group, a n-propyl group, an iso-propyl group, a n-butyl group, a sec-butyl group, an iso-butyl group and a tert-butyl group;

[0050] Optionally, the first template agent in step S1 and the second template agent in step S3 are an organic base; and each is independently preferably selected from at least one of a quaternary ammonium base, an aliphatic amine and an aliphatic alcohol amine;

[0051] Further preferably, the first template agent and the second template agent are each independently selected from at least one of a quaternary ammonium base having a structure shown in the following formula (B):

[0052] R1, R2, R3and R4are each independently selected from one or more of a linear alkyl group having 1 to 4 carbon atoms and a branched alkyl group having 3 to 4 carbon atoms, further preferably R1, R2, R3and R4are each independently selected from one or more of a methyl group, an ethyl group, a n-propyl group, an iso-propyl group, a n-butyl group, a sec-butyl group, an iso-butyl group and a tert-butyl group;

[0053] Further preferably, the first template agent and the second template agent are each independently tetrapropylammonium hydroxide or a mixture of tetrapropylammonium hydroxide and one or more of tetrapropylammonium chloride and tetrapropylammonium bromide.

[0054] Optionally, in step S1, the titanium source is selected from one or more of an organic titanium source and an inorganic titanium source;

[0055] The organic titanium source is a titanium-containing organic acid ester selected from at least one of a structure shown in the following formula (C):

[0056]

[0057] wherein R5, R6, R7and R8are each independently selected from one or more of a linear alkyl group having 1 to 6 carbon atoms and a branched alkyl group having 3 to 6 carbon atoms, further preferably R5, R6, R7and R8are each independently selected from one or more of a linear alkyl group having 1 to 4 carbon atoms and a branched alkyl group having 3 to 4 carbon atoms; optionally, R5, R6, R7and R8are each independently selected from one or more of a methyl group, an ethyl group, a n-propyl group, an iso-propyl group, a n-butyl group, a sec-butyl group, an iso-butyl group, a tert-butyl group, an iso-pentyl group, a hexyl group and an iso-hexyl group; preferably each is independently selected from one or more of an ethyl group, a n-propyl group, an iso-propyl group, a n-butyl group, a sec-butyl group, an iso-butyl group and a tert-butyl group;

[0058] the inorganic titanium source is selected from one or more of a chloride, a nitrate or a sulfate of titanium;

[0059] Preferably, the titanium source is selected from one or more of titanium tetrachloride, titanium sulfate, titanium nitrate, tetraethyl titanate, tetrapropyl titanate and tetrabutyl titanate.

[0060] Optionally, in step S1, the silanization agent has a general formula of R9Si(R 10 )(R 11 )R 12 , wherein R9, R 10 , R 11 , R 12 are each independently halogen, alkyl, alkoxy, aryl, thiol or amine, and at least one of R9, R 10 , R 11 , R 12 is alkyl, alkoxy, aryl, thiol or amine; the number of carbon atoms of the alkyl, alkoxy, thiol and amine is each independently C1-C 18 ;

[0061] Preferably, the silanization agent is selected from one or more of dimethyldichlorosilane, N-phenyl-3-aminopropyltrimethoxysilane, phenyltrimethoxysilane, 1,7-dichlorooctylmethyltetrasiloxane, hexadecyltrimethoxysilane, octyltriethoxysilane, 3-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane; further preferably, is selected from one or more of N-phenyl-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane and 3-mercaptopropyltrimethoxysilane.

[0062] Optionally, in step S1, the structure filler is selected from one or more of an amphiphilic surfactant and a hard template agent;

[0063] Preferably, the amphiphilic surfactant is selected from one or more of hexadecyltrimethylammonium bromide, sodium dodecylbenzenesulfonate, sodium branched dodecylbenzenesulfonate, α-olefin sulfonate with a carbon number of 14-16 and sodium secondary alkyl sulfonate;

[0064] Preferably, the hard template agent is selected from one or more of PEO-PPO-PEO block copolymer, mesoporous carbon, natural fiber, polyethylene, polypropylene, polyvinyl chloride, polystyrene and polyvinyl alcohol;

[0065] Further preferably, the structure filler is selected from one or more of hexadecyltrimethylammonium bromide, sodium dodecylbenzenesulfonate, PEO-PPO-PEO block copolymer, mesoporous carbon and natural cellulose.

[0066] Optionally, step S1 comprises:

[0067] a. mixing a titanium source, a silicon source, a first template agent and water to obtain a hydrolytic sol of silicon;

[0068] b. adding a silylating agent and a structure filler into the hydrolytic sol of silicon respectively, and mixing to obtain the reaction mixture;

[0069] Optionally, the mixing in step a is performed under the conditions of stirring at 40-90℃ for 6-12h.

[0070] Optionally, the mixing in step b is performed under the conditions of stirring at 20-50℃ for 2-4h.

[0071] Preferably, the silicon source is an organosilicon grease, and after mixing the silicon source, the first template agent and water, step a further comprises a hydrolytic alcohol-removing treatment to obtain the hydrolytic sol of silicon.

[0072] Optionally, the hydrolytic alcohol-removing treatment is performed under the conditions of stirring hydrolysis at 40-90℃ for 6-12h; preferably, stirring hydrolysis at 60-85℃ for 8-10h.

[0073] Optionally, in step S3, the weight ratio of the second template agent: water: molecular sieve intermediate is (0.2-3.5):(2-50):1; preferably (0.25-2.2):(3-35):1.

[0074] Optionally, the first hydrothermal crystallization treatment in step S2 and the second hydrothermal crystallization treatment in step S3 are each independently performed under the conditions of hydrothermal crystallization time of 6-168h, hydrothermal crystallization temperature of 130-200℃; preferably, hydrothermal crystallization time of 24-72h, hydrothermal crystallization temperature of 150-180℃; and pressure of autogenous pressure.

[0075] The first calcination treatment in step S2 and the second calcination treatment in step S3 are each independently performed under the conditions of calcination temperature of 300-700℃, calcination time of 1-16h; preferably, calcination temperature of 400-600℃, calcination time of 2-5h.

[0076] By the technical scheme, the method for preparing adiponitrile in a heterogeneous non-toxic solvent system is provided, the catalyst comprising the hierarchical pore titanosilicate molecular sieve is used for intramolecular rearrangement ring-opening cyano of cyclohexanone oxime, and under mild reaction conditions, high conversion rate of cyclohexanone oxime and selectivity of adiponitrile can be obtained, which has high industrial application value; titanium atom active centers are introduced into the hierarchical pore titanosilicate molecular sieve, which can enhance the deactivation resistance of the molecular sieve; the molecular sieve has a multi-cavity structure in the crystal, and the cavity structure has rich silicon hydroxyl active centers, the multi-cavity structure provides a large number of independent reaction units, and the concentrated distribution of the nest hydroxyls makes the molecular sieve have both acid and Lewis acid properties, and has a large specific surface area and pore volume, which is beneficial to efficient catalytic reaction.

[0077] Other features and advantages of the present disclosure will be described in detail in the following specific embodiment part. BRIEF DESCRIPTION OF DRAWINGS

[0078] The accompanying drawings are included to provide a further understanding of the present disclosure and constitute a part of the specification, and are used together with the following specific embodiments to explain the present disclosure, but do not constitute a limitation on the present disclosure. In the drawings:

[0079] Figure 1 TEM electron microscope picture of the molecular sieve product obtained in preparation example 1;

[0080] Figure 2 XRD spectrum of the molecular sieve product obtained in preparation example 1;

[0081] Figure 3 P-TMP MAS NMR spectrum of the molecular sieve product obtained in preparation example 1; 31

[0082] Figure 4 IR-OH spectrum of the molecular sieve product obtained in preparation example 1;

[0083] Figure 5 Si MAS NMR spectrum of the molecular sieve product obtained in preparation example 1; 29

[0084] Figure 6 H MAS NMR spectrum of the molecular sieve product obtained in preparation example 1; 1

[0085] Figure 7 SEM electron microscope picture of the molecular sieve product obtained in preparation example 1;

[0086] Figure 8 BET curve of the molecular sieve product obtained in preparation example 1;​​​​

[0087] Figure 9 TEM image of the intermediate product obtained in Example 1 for preparing;

[0088] Figure 10 XRD spectrum of the molecular sieve product obtained in Example 10 for preparing;

[0089] Figure 11 XRD spectrum of the molecular sieve product obtained in Example 11 for preparing. DETAILED DESCRIPTION

[0090] The detailed description of the specific embodiments of the present disclosure is described below. It should be understood that the specific embodiments described herein are only for illustration and explanation of the present disclosure, and are not intended to limit the present disclosure.

[0091] The present disclosure provides a method for preparing adiponitrile, comprising the following steps:

[0092] contacting cyclohexanone oxime, an ammonia source and a catalyst for catalytic reaction;

[0093] The catalyst comprises a hierarchical pore titanium silicate molecular sieve; the hierarchical pore titanium silicate molecular sieve has multiple cavity structures in the crystal.

[0094] The present disclosure provides a method for preparing adiponitrile in a non-homogeneous non-toxic solvent system, which uses a catalyst comprising a hierarchical pore titanium silicate molecular sieve for intramolecular rearrangement and ring-opening cyanation of cyclohexanone oxime, and under mild reaction conditions, high conversion rate of cyclohexanone oxime and selectivity of adiponitrile can be obtained, which has high industrial application value; and the titanium atom active center introduced into the hierarchical pore titanium silicate molecular sieve can enhance the deactivation resistance of the molecular sieve; and the molecular sieve has multiple cavity structures in the crystal, and the cavity structure has rich silicon hydroxyl active centers, the multiple cavity structures provide a large number of independent reaction units, and the concentrated distribution of the hydroxyl groups makes the molecular sieve have both acid and Lewis acid properties, and has large specific surface area and pore volume, which is beneficial for efficient catalytic reaction.

[0095] In a preferred embodiment, the method further comprises:

[0096] contacting cyclohexanone oxime, an ammonia source and a catalyst for intramolecular rearrangement and ring-opening cyanation reaction in the presence of a solvent.

[0097] In a specific embodiment, the solvent is selected from one or more of methanol, ethanol, propanol, butanol and cyclohexanol; the ammonia source is selected from ammonia water or ammonia gas; preferably, the ammonia source is selected from ammonia water with a concentration of 25-30% by weight. The solvent and the reaction raw reagent used in the present disclosure are non-toxic and harmless reagents.

[0098] ​In one embodiment, the molar ratio of cyclohexanone oxime to solvent is 1:(3-100), preferably 1:(10-50); and the weight ratio of ammonia source to solvent, calculated as pure ammonia, is 1:(10-1000), preferably 1:(20-500).

[0099] In one embodiment, the catalytic reaction is carried out under the following conditions: a reaction temperature of 200-450°C; a reaction time of 1-72h; a reaction pressure of 0.1-3MPa; a weight hourly space velocity of cyclohexanone oxime of 0.1-25h -1 .

[0100] In one preferred embodiment, the catalytic reaction is carried out under the following conditions: a reaction temperature of 350-400°C; a reaction time of 10-24h; a reaction pressure of 0.1-2MPa; a weight hourly space velocity of cyclohexanone oxime of 0.5-12h -1 . The reaction conditions according to this embodiment can achieve higher conversion of cyclohexanone oxime and selectivity of adiponitrile.

[0101] The multi-level pore titanium silicalite molecular sieve used in the reaction for preparing adiponitrile according to the present disclosure has multiple large-size cavity structures in the crystal, which facilitates the catalytic reaction.

[0102] In one embodiment, the size of the individual cavity structure of the multi-level pore titanium silicalite molecular sieve is 2-50nm, preferably 5-40nm. Optionally, the shape of the cavity structure is selected from one or more of a sphere, a cube, an ellipsoid, and an irregular cube.

[0103] In one preferred embodiment, the volume of all the cavity structures accounts for 10-50%, further preferably 15-45%, of the total volume of the molecular sieve.

[0104] In one preferred embodiment, the multi-level pore titanium silicalite molecular sieve has the following 31 P MAS NMR characteristics:

[0105] The peak intensity of the characteristic peak of the multi-level pore titanium silicalite molecular sieve at a chemical shift of -6±1ppm is denoted as N1; the peak intensity of the characteristic peak of the multi-level pore titanium silicalite molecular sieve at a chemical shift of -34±1ppm is denoted as N2; and the peak intensity of the characteristic peak of the multi-level pore titanium silicalite molecular sieve at a chemical shift of -61±1ppm is denoted as N3.

[0106] X as defined in the following formula (1-1) 1-1 is any value between 0.15 and 0.30;

[0107] X 1-1 = N1 / N3 formula (1-1); and

[0108] X is defined as follows (1-2) 1-2 It can be any value between 0.10 and 0.25;

[0109] X 1-2 = N2 / N3 (1-2);

[0110] Preferably, the X 1-1 X is any value between 0.18 and 0.29; 1-2 It can be any value between 0.12 and 0.20.

[0111] The inventors of this disclosure have discovered that when a multi-level porous titanium-silicon molecular sieve simultaneously possesses... When considering acid and Lewis acid properties, trimethylphosphorus (TMP) is used as a probe molecule. 31 In the pMAS NMR spectrum, the peak with a chemical shift of -6 ± 1 ppm was used as... The characteristic peaks of the acid properties were determined, with the peak at a chemical shift of -34±1 ppm taken as the characteristic peak of Lewis acid properties, and the peak at a chemical shift of -61±1 ppm taken as the characteristic peak of TMP physisorption. Using this characteristic peak of TMP physisorption as a benchmark, [the following was determined]. The characteristic peaks of the acid properties and the Lewis acid properties were compared with the characteristic peak of the TMP physisorption. The ratio of the peak intensity of each of the two acid properties to the peak intensity of the TMP physisorption characteristic peak was satisfied with the above X. 1-1 and X 1-2 When the range is within a certain range, the hierarchical porous titanium-silicon molecular sieve can have better catalytic activity and reaction stability.

[0112] In this disclosure, for hierarchical porous titanium-silicon molecular sieves... 31 Trimethylphosphorus (TMP) was used as the probe molecule in the P-TMP MAS NMR spectrum test, and the test method was a conventional method in this field.

[0113] In a preferred embodiment, the hierarchical porous titanium-silicon molecular sieve has the following characteristics: 29 Si MASNMR characteristics:

[0114] The peak area of ​​the spectral peak at the position with a chemical shift of -103±1ppm for the framework heteroatom molecular sieve is denoted as Q. 3 The peak area of ​​the spectral peak at the position with a chemical shift of -113±1ppm for the framework heteroatom molecular sieve is denoted as Q. 4-1 The peak area of ​​the spectral peak at the position with a chemical shift of -116±1ppm for the framework heteroatom molecular sieve is denoted as Q. 4-2 ;

[0115] X is defined as follows (2-1)2-1 X is any value between 0.04 and 0.45:

[0116] X 2-1 = Q 3 / Q 4-1 Formula (2-1);

[0117] X as defined in the following Formula (2-2) 2-2 X is any value between 0.15 and 0.65:

[0118] X 2-2 = Q 3 / Q 4-2 Formula (2-2);

[0119] Preferably, X 2-1 X is any value between 0.08 and 0.28, and X 2-2 X is any value between 0.25 and 0.48. The titanium silicalite molecular sieve used in the present disclosure has abundant silicon hydroxyl active centers.

[0120] In a preferred embodiment, the hierarchical pore titanium silicalite molecular sieve has the following 1 H MAS NMR characteristics:

[0121] The peak area of the spectrum peak at a chemical shift of 1.8±0.1 ppm is denoted as A1, the peak area of the spectrum peak at a chemical shift of 2.2±0.1 ppm is denoted as A2, the peak area of the spectrum peak at a chemical shift of 2.8±0.1 ppm is denoted as A3, the peak area of the spectrum peak at a chemical shift of 3.8±0.1 ppm is denoted as A4, and the peak area of the spectrum peak at a chemical shift of 4.6±0.1 ppm is denoted as A5.

[0122] X3 as defined in the following Formula (3) is any value between 0.1 and 1.2:

[0123] X3 = A1 / (A2+A3+A4+A5) Formula (3);

[0124] Preferably, X3 is any value between 0.2 and 0.9. In the present disclosure, in the 1 H MAS NMR spectrum of the hierarchical pore titanium silicalite molecular sieve, the spectrum peak at a chemical shift of 1.8±0.1 ppm represents isolated silicon hydroxyl in the molecular sieve, and the spectrum peaks at a chemical shift within 2-6 ppm (2.8 ppm±0.1 ppm, 3.8±0.1 ppm, and 4.6±0.1 ppm) represent hydrogen-bonded silicon hydroxyl. The titanium silicalite molecular sieve contains a small amount of isolated silicon hydroxyl and a large amount of hydrogen-bonded silicon hydroxyl, which helps to improve the catalytic performance of the titanium silicalite molecular sieve in the reaction of preparing adiponitrile from cyclohexanone oxime.

[0125] In an embodiment, the molar ratio of silicon atoms to titanium atoms in the multi-level pore titanosilicate molecular sieve is (10-100):1, preferably (15-80):1; the molar ratio of silicon atoms to titanium atoms in the molecular sieve is obtained by X-ray fluorescence spectrometer analysis method.

[0126] In a specific embodiment, the multi-level pore titanosilicate molecular sieve is selected from one or more of MFI structure molecular sieve, MEL structure molecular sieve, BEA structure molecular sieve, MWW structure molecular sieve, two-dimensional hexagonal structure molecular sieve, MOR structure molecular sieve, and TUN structure molecular sieve; preferably selected from one or more of MFI structure molecular sieve, MEL structure molecular sieve, BEA structure molecular sieve, MCM structure molecular sieve, and SBA structure molecular sieve; further preferably one or more of MFI structure molecular sieve, MEL structure molecular sieve, and BEA structure molecular sieve.

[0127] In a specific embodiment, the multi-level pore titanosilicate molecular sieve comprises molecular sieve particles composed of a single crystal grain, and / or molecular sieve particles composed of a plurality of crystal grains aggregated together.

[0128] Optionally, the average particle size of the molecular sieve particles is 0.1-0.8 μm, preferably 0.15-0.65 μm; the BET specific surface area is 250-650 m 2 / g, preferably 280-600 m 2 / g; the micropore specific surface area is 280-550 m 2 / g, preferably 300-500 m 2 / g; the total pore volume is 0.2-0.55 cm 3 / g, preferably 0.25-0.50 cm 3 / g; the mesopore volume is 0.1-0.4 cm 3 / g, preferably 0.15-0.35 cm 3 / g.

[0129] In an embodiment, the multi-level pore titanosilicate molecular sieve has a hysteresis loop between the adsorption isotherm and the desorption isotherm of low-temperature nitrogen adsorption; preferably, the starting relative pressure (P / P0) at which the hysteresis loop appears is 0.3-0.55.

[0130] In a preferred embodiment, the multi-level pore titanosilicate molecular sieve is prepared by a preparation method comprising the following steps:

[0131] S1, mixing a titanium source, a silicon source, a first template agent, water, a silylation reagent, and a structure filler to obtain a reaction mixture;

[0132] S2, sequentially performing a first hydrothermal crystallization treatment and a first calcination treatment on the reaction mixture to obtain a molecular sieve intermediate;

[0133] S3, mixing the molecular sieve intermediate, the second template agent and water, and then sequentially performing a second hydrothermal crystallization treatment and a second calcination treatment.

[0134] According to the present embodiment, the titanium source is introduced into the reaction raw materials, so that titanium atom active centers can be introduced into the molecular sieve framework during the synthesis of the molecular sieve; the silanization reagent and the macromolecular structure filler are introduced into the raw materials for the synthesis of the molecular sieve, so that the effect of expanding the molecular sieve layer can be achieved, and a molecular sieve material with open pores is prepared, and then a second template agent is added to perform dissolution-recrystallization, so that a hierarchical pore titanium silicate molecular sieve with a multi-cavity structure is prepared.

[0135] Specifically, during the preparation of the molecular sieve, the silanol groups of the silanization reagent can hydrolyze and condense with the silanol groups of the organosilicon source to generate stable Si-O-Si bonds, so that the effect of expanding the layer can be achieved. In addition, the long carbon chain of the silanization reagent and the structure filler of the amphiphilic surfactant can form stable and controllable structure units (the long carbon chain of the silanization reagent is close to the hydrophobic group of the surfactant to interact with each other by van der Waals force), so as to finely adjust the expansion of the layer; or the size-controllable hard template agent plays a role in space filling, so that the molecular sieve has an ordered and controllable pore size (controlled by the length of the alkyl chain of the silanization reagent) mesoporous structure; then a second template agent is introduced into the molecular sieve with open pores, and a hierarchical pore titanium silicate molecular sieve is obtained by using the dissolution-recrystallization mechanism of the second template agent.

[0136] In one embodiment, in step S1, the molar ratio of the titanium source: the silicon source: the first template agent: water: the silanization reagent is (0.002-0.15): 1: (0.01-4): (1-50): (0.02-0.35); and the weight ratio of SiO2 to the structure filler in the reaction mixture is (5-50): 1.

[0137] In a preferred embodiment, in step S1, the molar ratio of the titanium source: the silicon source: the first template agent: water: the silanization reagent is (0.01-0.06): 1: (0.02-1.5): (10-30): (0.03-0.15); and the weight ratio of SiO2 to the structure filler in the reaction mixture is (8-30): 1. The titanium silicate molecular sieve prepared according to the present embodiment has higher catalytic activity and reaction stability.

[0138] In one embodiment, in step S1, the silicon source is selected from at least one of organosilicon grease, solid silica gel, white carbon black and silica sol; preferably, the silicon source is selected from at least one of organosilicon grease, solid silica gel and white carbon black;

[0139] Further preferred is an organosilicon grease, the general formula of which is a structure shown in the following formula (A):

[0140]

[0141] wherein R a , R b , R c , R d are each independently selected from an alkyl group having 1 to 6 carbon atoms, the alkyl group being a branched or straight chain alkyl group; preferably, R a , R b , R c , R d are each independently selected from a straight chain alkyl group having 1 to 4 carbon atoms or a branched alkyl group having 3 to 4 carbon atoms; further preferably, the R a , R b , R c , R d are each independently selected from a methyl group, an ethyl group, a n-propyl group, an i-propyl group, a n-butyl group, a sec-butyl group, an i-butyl group or a t-butyl group.

[0142] In a preferred embodiment, the organosilicon grease is selected from one or more of tetramethyl silicate, tetraethyl silicate, tetrabutyl silicate and dimethyldiethyl silicate.

[0143] In one embodiment, in step S1, the first template agent is an organic base, preferably at least one selected from a quaternary ammonium base, an aliphatic amine and an aliphatic alcohol amine.

[0144] In a specific embodiment, the first template agent is selected from at least one of the quaternary ammonium bases having a structure shown in the following formula (B):

[0145] R1, R2, R3and R4are each selected from one or more of an alkyl group having 1 to 4 carbon atoms, preferably one or more of a straight chain alkyl group having 1 to 4 carbon atoms and a branched alkyl group having 3 to 4 carbon atoms, further preferably R1, R2, R3and R4are each selected from one or more of a methyl group, an ethyl group, a n-propyl group, an i-propyl group, a n-butyl group, a sec-butyl group, an i-butyl group and a t-butyl group.

[0146] In a preferred embodiment, the first template agent is tetrapropyl ammonium hydroxide or is a mixture of tetrapropyl ammonium hydroxide and one or more selected from tetrapropyl ammonium chloride and tetrapropyl ammonium bromide.

[0147] In one embodiment, step S1 comprises:

[0148] a. mixing a titanium source, a silicon source, a first template agent and water to obtain a hydrolytic sol of silicon;

[0149] b. adding a silylating agent and a structure filler into the hydrolytic sol of silicon respectively, and obtaining the reaction mixture after mixing;

[0150] Optionally, the mixing in step a is performed under the conditions of stirring at 40-90 °C for 6-12 h.

[0151] Optionally, the mixing in step b is performed under the conditions of stirring at 20-50 °C for 2-4 h.

[0152] In one specific embodiment, the silicon source is an organosilicon grease, and after mixing the silicon source, the first template agent and water in step a, a hydrolytic alcohol-removing treatment is further performed to obtain the hydrolytic sol of silicon.

[0153] Optionally, the hydrolytic alcohol-removing treatment is performed under the conditions of stirring hydrolysis at 40-90 °C for 6-12 h; preferably, stirring hydrolysis at 60-85 °C for 8-10 h. Preferably, the hydrolytic alcohol-removing treatment makes the mass content of alcohol produced by the hydrolysis of the organosilicon grease in the hydrolytic sol of silicon be less than 10 ppm.

[0154] In one embodiment, in step S1, the titanium source is selected from one or more of an organic titanium source and an inorganic titanium source.

[0155] The organic titanium source is a titanium-containing organic acid ester selected from at least one of the structures shown in the general formula (C):

[0156]

[0157] wherein R5, R6, R7and R8are each selected from an alkyl group having 1-6 carbon atoms, preferably a linear alkyl group having 1-4 carbon atoms and a branched alkyl group having 3-6 carbon atoms, further preferably R5, R6, R7and R8are each selected from a linear alkyl group having 2-4 carbon atoms and a branched alkyl group having 2-4 carbon atoms; optionally, R5, R6, R7and R8are each selected from one of methyl, ethyl, n-propyl, i-propyl, n-butyl, sec-butyl, i-butyl, t-butyl, i-pentyl, hexyl or i-hexyl; preferably, each independently is selected from one of ethyl, n-propyl, i-propyl, n-butyl, sec-butyl, i-butyl or t-butyl;

[0158] The inorganic titanium source is selected from one or more of a chloride, a nitrate or a sulfate of titanium.

[0159] In one preferred embodiment, the titanium source is selected from one or more of titanium tetrachloride, titanium sulfate, titanium nitrate, tetraethyl titanate, tetrapropyl titanate and tetrabutyl titanate.

[0160] In one embodiment, in step S1, the silylating agent has the general formula R9Si(R 10)(R 11 )R 12 , R 10 , R 11 , R 12 are each independently halogen, alkyl, alkoxy, aryl, thiol or amine, and at least one of R 10 , R 11 , R 12 is alkyl, alkoxy, aryl, thiol or amine; the number of carbon atoms of the alkyl, alkoxy, thiol and amine is each independently C1-C 18 .

[0161] In one embodiment, the silanization agent is selected from one or more of dimethyldichlorosilane, N-phenyl-3-aminopropyltrimethoxysilane, phenyltrimethoxysilane, 1,7-dichlorooctylmethyltetrasiloxane, hexadecyltrimethoxysilane, octyltriethoxysilane, 3-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, and 3-mercaptopropyltrimethoxysilane; and further preferably selected from one or more of N-phenyl-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, and 3-mercaptopropyltrimethoxysilane.

[0162] In one embodiment, the structural filler is selected from one or more of amphiphilic surfactants and hard templates.

[0163] In one embodiment, the amphiphilic surfactant is selected from one or more of hexadecyltrimethylammonium bromide, sodium dodecylbenzenesulfonate, sodium branched dodecylbenzenesulfonate, α-olefin sulfonate with a carbon number of 14-16, and sodium secondary alkyl sulfonate.

[0164] The hard template is selected from one or more of PEO-PPO-PEO block copolymer, mesoporous carbon, natural fiber, polyethylene, polypropylene, polyvinyl chloride, polystyrene, and polyvinyl alcohol.

[0165] In one preferred embodiment, the structural filler is selected from one or more of hexadecyltrimethylammonium bromide, sodium dodecylbenzenesulfonate, PEO-PPO-PEO block copolymer, mesoporous carbon, and natural cellulose.

[0166] The reagents used in the present disclosure can be purchased through conventional channels or prepared through known methods.

[0167] In one embodiment, the conditions of the first hydrothermal crystallization treatment in step S2 include a hydrothermal crystallization time of 6-168 h, a hydrothermal crystallization temperature of 130-200 ℃, and a pressure of autogenous pressure.

[0168] The first calcination treatment in step S2 includes a calcination temperature of 300-700°C and a calcination time of 1-16h.

[0169] In a preferred embodiment, the first hydrothermal crystallization treatment in step S2 includes a hydrothermal crystallization time of 24-72h, a hydrothermal crystallization temperature of 150-180°C, and an autogenous pressure.

[0170] The first calcination treatment in step S2 includes a calcination temperature of 400-600°C and a calcination time of 2-5h. The hierarchical porous titanosilicate molecular sieve prepared according to this embodiment has better catalytic activity.

[0171] In a specific embodiment, after the first hydrothermal crystallization treatment, the product of the first hydrothermal crystallization treatment is subjected to a first filtration treatment and a first drying treatment, and then subjected to the first calcination treatment. The first drying treatment is performed at a temperature of 50-120°C for 1-12h.

[0172] In an embodiment, the second template agent in step S3 is selected from the same range as the first template agent, which is not described again here. Preferably, the first template agent and the second template agent are the same template agent.

[0173] In an embodiment, the weight ratio of the second template agent:water:molecular sieve intermediate in step S3 is (0.2-3.5):(2-50):1, and preferably (0.25-2.2):(3-35):1. According to the preferred weight ratio in this embodiment, a molecular sieve with higher catalytic activity can be obtained.

[0174] In an embodiment, the second hydrothermal crystallization treatment in step S3 includes a hydrothermal crystallization time of 6-168h, a hydrothermal crystallization temperature of 130-200°C, and an autogenous pressure.

[0175] The second calcination treatment in step S3 includes a calcination temperature of 300-700°C and a calcination time of 1-16h.

[0176] In a preferred embodiment, the second hydrothermal crystallization treatment in step S3 includes a hydrothermal crystallization time of 24-72h, a hydrothermal crystallization temperature of 150-180°C, and an autogenous pressure.

[0177] The second calcination treatment in step S3 includes a calcination temperature of 400-600°C and a calcination time of 2-5h.

[0178] In one embodiment, after the second hydrothermal crystallization treatment, the product of the second hydrothermal crystallization treatment is subjected to a second filtration treatment, a second drying treatment, and then the second calcination treatment. The temperature of the second drying treatment is 50-120°C, and the time is 1-12h.

[0179] The present disclosure is described in detail below with reference to examples. However, the present disclosure is not limited to the examples.

[0180] The sample was characterized by 31 The P-TMP MAS NMR spectrum was obtained on an AVANCE III 600WB NMR spectrometer using a 4mm double resonance probe, a Ф4mm ZrO2 rotor, a resonance frequency of 242.9MHz, a magic angle spinning speed of 10kHz, a pulse width of 1.4μs, a recycle delay time of 1s, and about 6000 scans.

[0181] The sample was characterized by 3 / Q 4 The measurement method used 29 The Si MAS NMR spectrum was obtained on an AVANCE III 500WB NMR spectrometer using a 7mm double resonance probe, a Ф7mm ZrO2 rotor, a resonance frequency of 99.3MHz, a magic angle spinning speed of 5kHz, a pulse width of 1.8μs, a recycle delay time of 2s, and about 3000 scans.

[0182] The sample was characterized by 1 The H MAS NMR spectrum was obtained on a Varian Infinityplus-400 spectrometer using a 4mm double resonance probe, a Ф4mm ZrO2 rotor, a resonance frequency of 400.1MHz, a magic angle spinning speed of 10kHz, a pulse width of 3.57μs, a recycle delay time of 1s, and about 4000 scans.

[0183] The sample was characterized by Fourier transform infrared (FT-IR) spectroscopy on a Nicolet 8210 Fourier transform infrared spectrometer in the range of 400-4000cm -1 .

[0184] The sample was characterized by X-ray diffraction (XRD) on a Siemens D5005 X-ray diffractometer using Kα(Cu) radiation in the range of 0.5°-70°.

[0185] The transmission electron microscope (TEM) picture of the sample was obtained on a FEI Tecnai G2 F20 S-TWIN transmission electron microscope. The cavity structure and its size were obtained according to the TEM electron microscope test. The volume content of the cavity structure in the sample was obtained by measuring the transmission electron microscope (TEM) picture: the volume of each cavity in the molecular sieve particle was measured according to the TEM picture (calculated as a sphere, taking the middle value of the sum of the maximum length and the minimum length passing through the center of the cavity structure as the diameter of the sphere, and then calculating the percentage of the total volume of the cavities to the total volume of the molecular sieve particle; the average value was obtained after measuring the volume fraction of the cavity structure of 50 molecular sieve particles).

[0186] The scanning electron microscope (SEM) picture of the sample was obtained on a Hitachi S4800 high-resolution cold field emission scanning electron microscope. The average particle size of the sample was tested by measuring the SEM electron microscope picture (the average value was obtained after measuring the particle size of 50 molecular sieve particles).

[0187] The total specific surface area and the total pore volume of the sample were determined on a Micromeritics ASAP 245 static nitrogen adsorption instrument according to the standard method of ASTM D4222-98. The adsorption isotherm and desorption isotherm of the sample were determined according to the standard method of ASTM D4222-98.

[0188] The X-ray fluorescence analysis (determination of the molar ratio of silicon to titanium in the molecular sieve) of the sample was determined by a Rigaku 3013 instrument, tungsten target, excitation voltage 40 kV, excitation current 250 mA.

[0189] The reagents used in the following examples and comparative examples of the present disclosure were purchased through conventional channels.

[0190] The following multi-level pore titanium silicate molecular sieve was prepared by preparing examples.

[0191] Preparation Example 1

[0192] (1) 6 g of tetrabutyl titanate (0.0176 mol), 104 g of tetraethyl silicate (0.5 mol), 65 g of a 25 wt% tetrapropylammonium hydroxide (TPAOH, 0.08 mol) aqueous solution, and 140 g of water were sequentially added to a 500 mL beaker, placed on a magnetic stirrer with heating and stirring functions, mixed uniformly, and stirred at 60°C for 5 hours, and the evaporated water was supplemented in a timely manner, to obtain a colorless transparent titanium silicate sol;

[0193] (2) Add 9g of N-phenyl-3-aminopropyltrimethoxysilane (PHAPTMS, 0.035mol) and 3g of PEO-PPO-PEO triblock copolymer (P123, purchased from Inokai, weight average molecular weight 5800) to the mixture in step (1) and stir for 2 hours.

[0194] (3) The mixture obtained in step (2) is transferred to a stainless steel sealed reactor and crystallized at 170°C for 24 hours to obtain a sample. The sample is filtered, washed, dried at 110°C for 3 hours, and then calcined in a muffle furnace at 550°C for 3 hours to obtain intermediate product M-1 (molecular sieve intermediate).

[0195] (4) Mix 10g of M-1 molecular sieve intermediate sample, 20g of 25% by weight tetrapropylammonium hydroxide (TPAOH, 5g) aqueous solution and 40g of water evenly (the weight ratio of second template agent: water: molecular sieve intermediate is 0.5:5.5:1), transfer to a stainless steel closed reactor, and crystallize at 170℃ for 24h to obtain the sample. Filter and wash the obtained sample, dry it at 110℃ for 3 hours, and then calcine it in a muffle furnace at 550℃ for 3 hours to obtain a multi-level porous titanium silicon molecular sieve sample, denoted as CAT-1.

[0196] The structural parameter characterization results of sample CAT-1 are listed in Table 2;

[0197] TEM electron microscope image of sample CAT-1 as follows Figure 1 As shown in the figure, the molecular sieve has a hierarchical porous structure with multiple cavities within the crystal; and the size of a single cavity structure is 5–35 nm; the TEM image of the intermediate product M-1 before dissolution and recrystallization is as follows. Figure 9 As shown, Figure 9 and Figure 1 By comparison, it can be seen that Figure 1 The intermediate products, after being dissolved and recrystallized, created a large number of intracrystalline multi-cavity structures;

[0198] The XRD pattern of sample CAT-1 is as follows Figure 2 As shown, this indicates that the titanium silicate molecular sieve sample has an MFI topology.

[0199] Having a chemical shift of -6 ppm The acid signal, the Lewis acid signal at a chemical shift of -34 ppm, and the TMP physisorption signal at a chemical shift of -61 ppm, with the intensity values ​​of each peak being: N1 40175, N2 31842, N3 216929, and X calculated using equations (1-1) to (1-2). 1-1 and X 1-2 The values ​​are listed in Table 3;

[0200] The infrared hydroxyl spectrum of sample CAT-1 is as follows: Figure 4 As shown, distinct silanol active centers can be observed, with the 3740 cm⁻¹ site being particularly prominent. -1 The spectral peak at position 3690 cm⁻¹ represents a terminal hydroxyl group, indicating a side reaction center. -1 The spectral peak at position 3500 cm⁻¹ is for the ortho-hydroxyl group; -1 The spectral peak at the position is a nested silanol, indicating the main reaction center;

[0201] Sample CAT-1 29 Si MAS NMR spectrum as shown Figure 5 As shown in the figure, peaks are observed at chemical shifts of -103 ppm, -113 ppm, and -116 ppm, indicating that the molecular sieve sample contains silicon with silanol active centers and two coordination environments without hydroxyl groups. The peak areas Q of the three peaks were calculated by integration. 3 For 191772, Q 4-1 The value is 1225867, Q 4-2 X is 480975, calculated using equations (2-1) to (2-2). 2-1 and X 2-2 The values ​​are listed in Table 3;

[0202] Sample CAT-1 1 HMAS NMR spectrum as follows Figure 6 As shown in the figure, the titanium-silicon molecular sieve sample has an isolated silanol peak at a chemical shift of 1.8 ppm, and silanol peaks with hydrogen bonds between each other in the range of 2 to 6 ppm (2.2 ppm, 2.8 ppm, 3.8 ppm and 4.6 ppm, respectively). The peak areas of the above five peaks were calculated by integration and were: A1 = 18391, A2 = 13451, A3 = 25273, A4 = 23088 and A5 = 23459. The X3 values ​​calculated by formula (3) are listed in Table 3.

[0203] SEM images of sample CAT-1 are as follows: Figure 7 As shown in the figure, the molecular sieve consists of uniform ellipsoidal particles.

[0204] BET of sample CAT-1 Figure 8 As shown, there is a clear hysteresis loop between the nitrogen adsorption and desorption curves, and the initial relative pressure (P / P0) at which the hysteresis loop appears is 0.45.

[0205] Preparation of Comparative Example 1

[0206] The preparation comparative example 1 was prepared according to the method of preparation example 1, except that no silanization reagent and structure filler were added, and the product was recorded as D-1. The preparation conditions are listed in Table 1, and the characterization results of the molecular sieve obtained are listed in Tables 2-3.

[0207] Preparation comparative example 2

[0208] The conventional titanium silicate molecular sieve (Zeolites, 1992, Vol. 12, pp. 943-950) was prepared according to the existing method.

[0209] 22.5 g of tetraethyl silicate was mixed with 7.0 g of tetrapropyl ammonium hydroxide, and 59.8 g of deionized water was added and uniformly mixed. Then, hydrolysis was carried out at 60°C for 1.0 h to obtain a hydrolysis solution of tetraethyl silicate. Then, a solution composed of 1.1 g of tetrabutyl titanate and 5.0 g of isopropyl alcohol was slowly dropped into the above solution under the action of vigorous stirring, and the mixture was stirred at 75°C for 3 h to obtain a clear transparent colloid. Then, the colloid was transferred into a stainless steel sealed reaction kettle, and crystallization was carried out at 170°C for 3 days to obtain a conventional TS-1 molecular sieve, and the product was recorded as D-2. The preparation conditions are listed in Table 1, and the characterization results of the molecular sieve obtained are listed in Tables 2-3.

[0210] Preparation comparative example 3

[0211] The preparation comparative example 3 was prepared according to the method of preparation comparative example 2, except that a silanization reagent and a structure filler were added, which specifically included the following steps:

[0212] (1) 22.5 g of tetraethyl silicate was mixed with 7.0 g of tetrapropyl ammonium hydroxide, and 59.8 g of deionized water was added and uniformly mixed. Then, hydrolysis was carried out at 60°C for 1.0 h to obtain a hydrolysis solution of tetraethyl silicate. Then, a solution composed of 1.1 g of tetrabutyl titanate and 5.0 g of isopropyl alcohol was slowly dropped into the above solution under the action of vigorous stirring, and the mixture was stirred at 75°C for 3 h to obtain a clear transparent colloid.

[0213] (2) 1.9 g of N-phenyl-3-aminopropyl trimethoxysilane (PHAPTMS) and 0.65 g of PEO-PPO-PEO triblock copolymer (P123, purchased from Innoke, weight average molecular weight 5800) were added to the mixture of step (1), and stirred for 2 hours;

[0214] (3) Then, the colloid was transferred into a stainless steel sealed reaction kettle, and crystallization was carried out at 170°C for 3 days to obtain an expanded TS-1 molecular sieve, recorded as D-3. The preparation conditions are listed in Table 1, and the characterization results of the molecular sieve obtained are listed in Tables 2-3.

[0215] Preparation examples 2-9

[0216] The hierarchical porous titanosilicate molecular sieve was prepared according to the method of Preparation Example 1, except that the ratio and the synthesis conditions were changed, and the hierarchical porous titanosilicate molecular sieve sample was recorded as CAT-2 to CAT-9; the preparation conditions are listed in Table 1, and the characterization results of the obtained molecular sieve are listed in Tables 2 to 3.

[0217] Preparation Example 10

[0218] The hierarchical porous titanosilicate molecular sieve with MEL structure was prepared according to the method of Preparation Example 1, except that the template was changed, and the template used was tetrabutylammonium hydroxide (TBAOH), and the hierarchical porous titanosilicate molecular sieve sample was recorded as CAT-10; the preparation conditions are listed in Table 1, and the characterization results of the obtained molecular sieve are listed in Tables 2 to 3. The XRD of CAT-10 is shown in Figure 10 Figure 2, which shows that CAT-10 has MEL structure.

[0219] Preparation Example 11

[0220] The hierarchical porous β molecular sieve was prepared according to the method of Preparation Example 1, except that the ratio and the template were changed, and the template used was tetraethylammonium hydroxide (TEAOH), and the BEA topological structure was prepared, and the hierarchical porous titanosilicate molecular sieve sample was recorded as CAT-11; the preparation conditions are listed in Table 1, and the characterization results of the obtained molecular sieve are listed in Tables 2 to 3. The XRD of CAT-11 is shown in Figure 11 Figure 3, which shows that CAT-11 has BEA structure.

[0221] Preparation Example 12

[0222] The hierarchical porous titanosilicate molecular sieve was prepared according to the method of Preparation Example 1, except that:

[0223] The temperature of the first hydrothermal crystallization treatment was 130°C, and the time was 96h; the temperature of the first calcination treatment was 350°C, and the time was 8h;

[0224] The temperature of the second hydrothermal crystallization treatment was 130°C, and the time was 96h; the temperature of the second calcination treatment was 350°C, and the time was 8h;

[0225] The hierarchical porous titanosilicate molecular sieve sample was recorded as CAT-12; the characterization results of the obtained molecular sieve are listed in Tables 2 to 3.

[0226] Table 1

[0227]

[0228]

[0229] In Table 1, TPAOH is tetrapropylammonium hydroxide, TBAOH is tetrabutylammonium hydroxide, TEAOH is tetraethylammonium hydroxide; PHAPTMS is N-phenyl-3- aminopropyltrimethoxysilane, APTMS is 3-aminopropyltriethoxysilane, GCPMS is 3- glycidoxypropyl(dimethoxy)methylsilane, TOMS is methyltrimethoxysilane; P123 is PEO- PPO-PEO triblock copolymer, CTAB is cetyltrimethylammonium bromide. The reagents used in the present disclosure can be obtained through conventional purchase channels. The water in the calculation of "water / silicon source" in Table 1 also includes water from the first template aqueous solution; the water in the calculation of "water / molecular sieve intermediate" also includes water from the second template aqueous solution.

[0230] Table 2

[0231]

[0232] Table 3

[0233]

[0234]

[0235] Reaction Example 1

[0236] This reaction example is used to illustrate the effect of the method provided by the present disclosure for preparing adiponitrile.

[0237] The samples prepared in the above preparation examples and preparation comparative examples were used as catalysts for the intramolecular rearrangement and ring-opening cyanylization reaction of cyclohexanone oxime, and the evaluation device was a normal-pressure continuous-flow fixed-bed reactor with an inner diameter of 5 mm and a catalyst loading of 2 g. After loading the catalyst, the reactor was pretreated in a nitrogen atmosphere at normal pressure and 350°C for 3 h. The concentration of the raw material cyclohexanone oxime was 10% by weight, and the solvent was methanol (molar ratio of cyclohexanone oxime to solvent was 1:10). The reaction conditions included a cyclohexanone oxime weight hourly space velocity (WHSV, flow rate of cyclohexanone oxime in the feed / catalyst weight in the reactor) of 1 h -1 -1, the weight ratio of methanol to pure ammonia in aqueous ammonia was 30, the reaction temperature was 380°C, the nitrogen flow rate was 4 L / h, and the reaction time was 12 h. The catalyst was reused for 10 times of the same catalytic reaction.

[0238] The cooled reaction product was collected, and the concentrations of various substances were quantitatively analyzed using a gas chromatograph. The gas chromatograph used was a 6890 type produced by Agilent, and the analysis column used was an HP-5 column. The test conditions included a vaporization chamber temperature of 250°C, a detection chamber temperature of 230°C, and a column temperature of programmed temperature rise, 110°C constant temperature for 8 min, then 15°C / min to 230°C constant temperature for 14 min. The results are shown in Table 4.

[0239] wherein the cyclohexanone oxime conversion % = (moles of cyclohexanone oxime in raw material - moles of cyclohexanone oxime in product) / moles of cyclohexanone oxime in raw material x 100%;

[0240] the adiponitrile selectivity % = moles of adiponitrile in product / (moles of cyclohexanone oxime in raw material - moles of cyclohexanone oxime in product) x 100%;

[0241] the cyclohexanone oxime conversion reduction rate % = (cyclohexanone oxime conversion rate of reaction 1 - cyclohexanone oxime conversion rate of reaction 10) / cyclohexanone oxime conversion rate of reaction 1 x 100%;

[0242] the adiponitrile selectivity reduction rate = (adiponitrile selectivity of reaction 1 - adiponitrile selectivity of reaction 10) / adiponitrile selectivity of reaction 1 x 100%.

[0243] Table 4

[0244]

[0245] According to the data in the above Table 4, it can be seen that:

[0246] Compared with the molecular sieves D-1 to D-3 prepared by using the preparation examples 1 to 3, the molecular sieves CAT-1 to CAT-12 provided in the disclosure have higher cyclohexanone oxime conversion rate and adiponitrile selectivity in the preparation of adiponitrile reaction, and the cyclohexanone oxime conversion rate reduction rate and the adiponitrile selectivity reduction rate are smaller when repeatedly used for many times, which indicates that the catalyst used in the method provided in the disclosure has better deactivation resistance and higher catalytic stability.

[0247] Comparing preparation example 1 with preparation example 9, the molecular sieve CAT-1 obtained by preparing the molecular sieve according to the raw material addition ratio in the preferred embodiment has higher cyclohexanone oxime conversion rate and adiponitrile selectivity in the catalytic reaction, and the catalyst has better deactivation resistance and higher catalytic stability.

[0248] Comparing preparation example 1 with preparation example 12, the molecular sieve CAT-1 obtained by preparing the molecular sieve according to the reaction conditions in the preferred embodiment has higher cyclohexanone oxime conversion rate and adiponitrile selectivity in the catalytic reaction, and the catalyst has better deactivation resistance and higher catalytic stability.

[0249] Reaction Comparative Example 1

[0250] This comparative example uses the method disclosed in the prior art CN112409210A to prepare adiponitrile, which specifically comprises:

[0251] (1) The catalyst for preparing adiponitrile was prepared by using the components of FeCl3: Cr(NO3)3: SiC = 5: 12: 100, dissolving FeCl3 and Cr(NO3)3 in water to the same volume of SiC, stirring and dissolving, immersing SiC in the mixed solution containing the catalyst precursor, standing for 12 hours, drying at 115℃, and calcining at 600℃ for 5 hours under nitrogen atmosphere.

[0252] (2) The reaction was carried out in a continuous flow fixed bed reactor, the catalyst loading was 10ml, the reducing medium was hydrogen, the reduction temperature was 450℃, the reduction pressure was normal pressure, and the reduction time was 6h. The preparation conditions were as follows: the volume ratio of acrylonitrile to N-methylpyrrolidone was 1.5:10, the space velocity was 1.5h -1 , the reaction temperature was 25℃, and the reaction pressure was normal pressure. The reaction results included: the conversion rate of acrylonitrile was 80.7mol% and the selectivity of adiponitrile was 85.2mol%. Comparing reaction example 1 with reaction comparative example 1, it can be seen that the method provided by the present disclosure can obtain higher raw material conversion rate and reaction product selectivity.

[0253] Reaction examples 2-3

[0254] The same reaction device as reaction example 1 was used, and the difference from reaction example 1 was that the reaction conditions were changed, and the catalytic reaction was carried out according to the reaction conditions listed in the following table 5, and the reaction results are listed in table 6.

[0255] Table 5

[0256]

[0257] Table 6

[0258]

[0259] According to the above table 5-6, it can be seen that:

[0260] Comparing reaction example 3 with reaction example 1, it can be seen that when CAT-1 is used as the catalyst, reaction example 1 can achieve higher cyclohexanone oxime conversion rate and adiponitrile selectivity under the reaction conditions of “the weight ratio of ammonia source to solvent calculated by pure ammonia is 1: (20-500); the reaction temperature is 350-400℃; the reaction time is 10-24h; the reaction pressure is 0.1-2MPa; and the weight space velocity of cyclohexanone oxime is 0.3-13h -1 ”.

[0261] The above describes the preferred embodiments of the present disclosure in detail, but the present disclosure is not limited to the specific details in the above embodiments, and various simple modifications can be made to the technical solutions of the present disclosure within the technical concept of the present disclosure, and these simple modifications all belong to the protection scope of the present disclosure.

[0262] It should also be noted that any technically possible combination of the various technical features described in the above embodiments can be made, without contradiction. In order to avoid unnecessary repetition, the disclosure does not describe each possible combination of the various technical features.

[0263] Furthermore, any combination of the various different embodiments of the disclosure can also be made, as long as it does not contradict the idea of the disclosure, it should also be considered as disclosed by the disclosure.

Claims

1. A process for the preparation of adiponitrile, characterized in that, The method comprises the following steps: contacting cyclohexanone oxime, an ammonia source and a catalyst to perform a catalytic reaction; The catalyst comprises a hierarchical pore titanosilicate molecular sieve; the hierarchical pore titanosilicate molecular sieve has a plurality of cavity structures in the crystal.

2. The method of claim 1, wherein, The method further comprises: contacting cyclohexanone oxime, an ammonia source and a catalyst to perform an intramolecular rearrangement and ring-opening cyano reaction in the presence of a solvent.

3. The method of claim 2, wherein, The solvent is selected from one or more of methanol, ethanol, propanol, butanol and cyclohexanol; and the ammonia source is selected from ammonia water or ammonia gas.

4. The method of claim 3, wherein, The ammonia source is ammonia water with a concentration of 25-30% by weight.

5. The method of claim 2, wherein, The molar ratio of cyclohexanone oxime to the solvent is 1: (3-100); and the weight ratio of the ammonia source (calculated based on pure ammonia) to the solvent is 1: (10-1000).

6. The method of claim 5, wherein, The molar ratio of cyclohexanone oxime to the solvent is 1: (10-50); and the weight ratio of the ammonia source (calculated based on pure ammonia) to the solvent is 1: (20-500).

7. The method of claim 1, wherein, The conditions of the catalytic reaction include: reaction temperature is 200-450℃; reaction time is 1-72h; reaction pressure is 0.1-3MPa; weight space velocity of cyclohexanone oxime is 0.1-25h -1 .

8. The method of claim 7, wherein, The conditions of the catalytic reaction include: reaction temperature is 350-400℃; reaction time is 10-24h; reaction pressure is 0.1-2MPa; weight space velocity of cyclohexanone oxime is 0.5-12h -1 .

9. The method of claim 7, wherein, The reactor for the catalytic reaction is selected from any one of a fixed bed reactor, a tank reactor, a moving bed reactor, a suspended bed reactor or a slurry bed reactor.

10. The method of claim 1, wherein, The size of the single cavity structure of the hierarchical pore titanosilicate molecular sieve is 2-50 nm.

11. The method of claim 10, wherein, The size of the single cavity structure of the hierarchical pore titanosilicate molecular sieve is 5-40 nm.

12. The method of claim 1, wherein, The volume of all the cavity structures accounts for 10-50% of the total volume of the molecular sieve.

13. The method of claim 12, wherein, The volume of all the cavity structures accounts for 15-45% of the total volume of the molecular sieve.

14. The method of claim 1, wherein, The shape of the cavity structure is selected from one or more of a spherical shape, a cubic shape, an ellipsoidal shape and an irregular cubic shape.

15. The method of claim 1, wherein, The multi-level porous titanosilicate molecular sieve has the following 31 PMASNMR characteristics: The peak intensity of the characteristic peak at a chemical shift of -6±1 ppm of the hierarchical pore titanosilicate molecular sieve is denoted as N1; the peak intensity of the characteristic peak at a chemical shift of -34±1 ppm of the hierarchical pore titanosilicate molecular sieve is denoted as N2; and the peak intensity of the characteristic peak at a chemical shift of -61±1 ppm of the hierarchical pore titanosilicate molecular sieve is denoted as N3. X is as defined in formula (1-1) below 1-1 is any value between 0.15 and 0.30; X 1-1 = N1 / N3 formula (1-1); and X is as defined in formula (1-2) below 1-2 is any value between 0.10 and 0.25; X 1-2 = N2 / N3 formula (1-2).

16. The method of claim 15, wherein, said X 1-1 is any value between 0.18 and 0.29; said X 1-2 is any value between 0.12 and 0.

20.

17. The method of claim 1, wherein, The multi-level porous titanosilicate molecular sieve has the following 29 Si MAS NMR characteristics: the peak area of the spectrum peak at the position of the chemical shift of the framework heteroatom molecular sieve of -103 ± 1 ppm is recorded as Q 3 ; the peak area of the spectrum peak at the position of the chemical shift of the framework heteroatom molecular sieve of -113 ± 1 ppm is recorded as Q 4-1 ; the peak area of the spectrum peak at the position of the chemical shift of the framework heteroatom molecular sieve of -116 ± 1 ppm is recorded as Q 4-2 ; X as defined by formula (2-1) below 2-1 is any value between 0.04 and 0.45: X 2-1 =Q 3 / Q 4-1 Formula (2-1); X as defined in formula (2-2) below 2-2 is any value between 0.15 and 0.65: X 2-2 =Q 3 / Q 4-2 Formula (2-2).

18. The method of claim 17, wherein, X 2-1 is any value between 0.08 and 0.28, X 2-2 is any value between 0.25 and 0.

48.

19. The method of claim 1, wherein, The multi-level porous titanosilicate molecular sieve has the following 1 HM AS NMR characteristics: The peak area of the spectrum peak at a chemical shift of 1.8±0.1 ppm is denoted as A1, the peak area of the spectrum peak at a chemical shift of 2.2±0.1 ppm is denoted as A2, the peak area of the spectrum peak at a chemical shift of 2.8±0.1 ppm is denoted as A3, the peak area of the spectrum peak at a chemical shift of 3.8±0.1 ppm is denoted as A4, and the peak area of the spectrum peak at a chemical shift of 4.6±0.1 ppm is denoted as A5. X3 defined in the following formula (3) is any value between 0.1 and 1.2: X3=A1 / (A2+A3+A4+A5) formula (3).

20. The method of claim 19, wherein, X3 is any value between 0.2 and 0.

9.

21. The method of claim 1, wherein, The molar ratio of silicon atoms to titanium atoms in the hierarchical pore titanosilicate molecular sieve is (10-100):

1.

22. The method of claim 21, wherein, The molar ratio of silicon atoms to titanium atoms in the hierarchical pore titanosilicate molecular sieve is (15-80):

1.

23. The method of claim 1, wherein, The hierarchical pore titanosilicate molecular sieve is selected from one or more of an MFI structure molecular sieve, an MEL structure molecular sieve, a BEA structure molecular sieve, a MWW structure molecular sieve, a two-dimensional hexagonal structure molecular sieve, a MOR structure molecular sieve and a TUN structure molecular sieve.

24. The method of claim 23, wherein, The multi-level pore titanosilicate molecular sieve is selected from one or more of MFI structure molecular sieve, MEL structure molecular sieve, BEA structure molecular sieve, MCM structure molecular sieve and SBA structure molecular sieve.

25. The method of claim 24, wherein, The multi-level pore titanosilicate molecular sieve is selected from one or more of MFI structure molecular sieve, MEL structure molecular sieve and BEA structure molecular sieve.

26. The method of claim 1, wherein, The multi-level pore titanosilicate molecular sieve comprises molecular sieve particles composed of single crystal grains and / or molecular sieve particles composed of multiple crystal grains.

27. The method of claim 26, wherein, The average particle diameter of the molecular sieve particles is 0.1 to 0.8 μm; the BET specific surface area is 250 to 650 m 2 / g; the micropore specific surface area is 280 to 550 m 2 / g; the total pore volume is 0.2 to 0.55 cm 3 / g; the mesopore volume is 0.1 to 0.4 cm 3 / g.

28. The method of claim 27, wherein, The average particle diameter of the molecular sieve particles is 0.15 to 0.65 μm; the BET specific surface area is 280 to 600 m 2 / g; the micropore specific surface area is 300 to 500 m 2 / g; the total pore volume is 0.25 to 0.50 cm 3 / g; the mesopore volume is 0.15 to 0.35 cm 3 / g.

29. The method of claim 1, wherein, The multi-level pore titanosilicate molecular sieve has a hysteresis loop between the adsorption isotherm and the desorption isotherm of low-temperature nitrogen adsorption.

30. The method of claim 29, wherein, The starting relative pressure (P / P0) at which the hysteresis loop appears is 0.3-0.

55.

31. The method of claim 1, wherein, The multi-level pore titanosilicate molecular sieve is prepared by a preparation method comprising the following steps: S1, mixing a titanium source, a silicon source, a first template agent, water, a silylating agent and a structure filler to obtain a reaction mixture; S2, sequentially performing a first hydrothermal crystallization treatment and a first calcination treatment on the reaction mixture to obtain a molecular sieve intermediate; S3, mixing the molecular sieve intermediate, a second template agent and water, and then sequentially performing a second hydrothermal crystallization treatment and a second calcination treatment.

32. The method of claim 31, wherein, In step S1, the molar ratio of the titanium source: the silicon source: the first template agent: water: the silylating agent is (0.002-0.15):1:(0.01-4):(1-50):(0.02-0.35); and the weight ratio of SiO2 to the structure filler in the reaction mixture is (5-50):

1.

33. The method of claim 32, wherein, In step S1, the molar ratio of the titanium source: the silicon source: the first template agent: water: the silylating agent is (0.01-0.06):1:(0.02-1.5):(10-30):(0.03-0.15); and the weight ratio of SiO2 to the structure filler in the reaction mixture is (8-30):

1.

34. The method of claim 31, wherein, In step S1, the silicon source is selected from at least one of organic silicon grease, solid silica gel, white carbon black and silica sol.

35. The method of claim 34, wherein, In step S1, the silicon source is selected from at least one of organic silicon grease, solid silica gel and white carbon black.

36. The method of claim 35, wherein, In step S1, the silicon source is selected from organic silicon grease, and the general formula of the organic silicon grease is shown in the following formula (A): （A）； wherein R a , R b , R c , R d are each independently selected from an alkyl group having 1 to 6 carbon atoms, the alkyl group being a branched or straight chain alkyl group.

37. The method of claim 36, wherein, In formula (A), R a , R b , R c , R d each independently is selected from a linear alkyl group having 1 to 4 carbon atoms or a branched alkyl group having 3 to 4 carbon atoms.

38. The method of claim 36, wherein, In formula (A), the R a , R b , R c , R d each independently is selected from methyl, ethyl, n-propyl, i-propyl, n-butyl, sec-butyl, i-butyl or t-butyl.

39. The method of claim 36, wherein, The organic silicon grease is selected from one or more of tetramethyl silicate, tetraethyl silicate, tetrabutyl silicate and dimethyl diethyl silicon grease.

40. The method of claim 31, wherein, The first template agent in step S1 and the second template agent in step S3 are organic bases. The inorganic titanium source is selected from one or more of chlorides, nitrates or sulfates of titanium.

41. The method of claim 40, wherein, The first template agent in step S1 and the second template agent in step S3 are each independently selected from at least one of quaternary ammonium bases, aliphatic amines and aliphatic alcohol amines.

42. The method of claim 40, wherein, The first template agent and the second template agent are each independently selected from at least one of quaternary ammonium bases having the structure shown in the following formula (B): （B）； R1, R2, R3 and R4 are each selected from alkyl groups having 1-4 carbon atoms.

43. The method of claim 42, wherein, In formula (B), R1, R2, R3 and R4 are each selected from one or more of straight-chain alkyl groups having 1-4 carbon atoms and branched-chain alkyl groups having 3-4 carbon atoms.

44. The method of claim 42, wherein, In formula (B), R1, R2, R3 and R4 are each independently selected from one or more of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl and tert-butyl.

45. The method of claim 42, wherein, The first template agent and the second template agent are each independently tetrapropylammonium hydroxide or a mixture of tetrapropylammonium hydroxide and one or more of tetrapropylammonium chloride and tetrapropylammonium bromide.

46. The method of claim 31, wherein, In step S1, the titanium source is selected from one or more of an organic titanium source and an inorganic titanium source; The organic titanium source is a titanium-containing organic acid ester selected from at least one of the structures of the general formula (C): （C）； wherein R5, R6, R7 and R8 are each independently selected from an alkyl group having 1 to 6 carbon atoms.

47. The method of claim 46, wherein, In formula (C), R5, R6, R7 and R8 are each independently selected from a linear alkyl group having 1 to 4 carbon atoms and a branched alkyl group having 3 to 6 carbon atoms.

48. The method of claim 46, wherein, In formula (C), R5, R6, R7 and R8 are each independently selected from a linear alkyl group having 1 to 4 carbon atoms and a branched alkyl group having 3 to 6 carbon atoms.

49. The method of claim 46, wherein, In formula (C), R5, R6, R7 and R8 are each independently selected from one or more of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, isoamyl, hexyl or iso-hexyl.

50. The method of claim 46, wherein, In formula (C), R5, R6, R7 and R8 are each independently selected from one or more of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, isoamyl, hexyl or iso-hexyl.

51. The method of claim 40, wherein, The titanium source is selected from one or more of titanium tetrachloride, titanium sulfate, titanium nitrate, tetraethyl titanate, tetrapropyl titanate and tetrabutyl titanate.

52. The method of claim 31, wherein, In step S1, the silylating agent is selected from one or more of dimethyldichlorosilane, N-phenyl-3-aminopropyltrimethoxysilane, phenyltrimethoxysilane, 1,7-dichlorooctylmethyltetrasiloxane, hexadecyltrimethoxysilane, octyltriethoxysilane, 3-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane and 3-mercaptopropyltrimethoxysilane.

53. The method of claim 52, wherein, The silylating agent is selected from one or more of N-phenyl-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane and 3-mercaptopropyltrimethoxysilane.

54. The method of claim 31, wherein, In step S1, the structure filler is selected from one or more of an amphiphilic surfactant and a hard template agent.

55. The method of claim 54, wherein, The amphiphilic surfactant is selected from one or more of cetyltrimethylammonium bromide, sodium dodecylbenzenesulfonate, branched sodium dodecylbenzenesulfonate, α-olefin sulfonate having 14 to 16 carbon atoms and sodium secondary alkyl sulfonate.

56. The method of claim 54, wherein, The hard template agent is selected from one or more of PEO-PPO-PEO block copolymer, mesoporous carbon, natural fiber, polyethylene, polypropylene, polyvinyl chloride, polystyrene and polyvinyl alcohol.

57. The method of claim 54, wherein, The structure filler is selected from one or more of cetyltrimethylammonium bromide, sodium dodecylbenzenesulfonate, PEO-PPO-PEO block copolymer, mesoporous carbon and natural cellulose.

58. The method of claim 31, wherein, Step S1 comprises: a. mixing the titanium source, the silicon source, the first template agent and water to obtain a hydrolytic sol of silicon; b. adding a silanization reagent and a structure filler into the hydrolytic sol of silicon respectively, and obtaining the reaction mixture after mixing.

59. The method of claim 58, wherein, The mixing conditions in step a include stirring at 40-90℃ for 6-12h; and the mixing conditions in step b include stirring at 20-50℃ for 2-4h.

60. The method of claim 58, wherein, The silicon source is an organosilicon grease, and the mixing of the silicon source, the first template agent and water in step a further includes a hydrolytic alcohol-removing treatment to obtain the hydrolytic sol of silicon.

61. The method of claim 60, wherein, The conditions of the hydrolytic alcohol-removing treatment include stirring and hydrolysis at 40-90℃ for 6-12h.

62. The method of claim 61, wherein, The conditions of the hydrolytic alcohol-removing treatment include stirring and hydrolysis at 60-85℃ for 8-10h.

63. The method of claim 31, wherein, In step S3, the weight ratio of the second template agent: water: molecular sieve intermediate is (0.2-3.5):(2-50):

1.

64. The method of claim 63, wherein, In step S3, the weight ratio of the second template agent: water: molecular sieve intermediate is (0.25-2.2):(3-35):

1.

65. The method of claim 31, wherein, The conditions of the first hydrothermal crystallization treatment in step S2 and the second hydrothermal crystallization treatment in step S3 each independently include a hydrothermal crystallization time of 6-168h and a hydrothermal crystallization temperature of 130-200℃; and the pressure is autogenous pressure. The conditions of the first calcination treatment in step S2 and the second calcination treatment in step S3 each independently include a calcination temperature of 300-700℃ and a calcination time of 1-16h.

66. The method of claim 65, wherein, The conditions of the first hydrothermal crystallization treatment in step S2 and the second hydrothermal crystallization treatment in step S3 each independently include a hydrothermal crystallization time of 24-72h and a hydrothermal crystallization temperature of 150-180℃. The conditions of the first calcination treatment in step S2 and the second calcination treatment in step S3 each independently include a calcination temperature of 400-600℃ and a calcination time of 2-5h.

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