A method for preparing ketazine by imine oxidation with oxygen and a method for preparing hydrazine hydrate

Abstract

The present invention discloses a method for preparing ketazine by imine oxidation with oxygen, which comprises the following steps: under oxygen conditions, an imine compound is contacted with a catalyst for an oxidation reaction; the catalyst comprises a composite catalytic material of metal nanoparticles and molecular sieve, and the composite catalytic material comprises a silica molecular sieve and a metal element M dispersed in the intracrystalline of the silica molecular sieve; the metal M is selected from one or more of manganese, iron, cobalt, nickel, palladium, platinum, copper and gold. This method uses a metal-containing hierarchical pore molecular sieve for the oxidative coupling of imine with oxygen to prepare ketazine, without the need to add additional base and ligand, and high conversion rate and ketazine selectivity can be obtained at a relatively low temperature.

Description

Technical Field

[0001] The present application relates to the field of organic chemical industry, and specifically, to a method for preparing ketazine and hydrazine by imine oxidation with oxygen. Background Art

[0002] Hydrazine hydrate is an important fine chemical product and an important intermediate for pharmaceuticals, pesticides, and dyes. It is mainly used in the production of blowing agents such as AC blowing agent, OBSH blowing agent, adipic dihydrazide, etc.; hydrazine hydrate is also commonly used in the pharmaceutical industry, such as for the synthesis of drugs like isoniazid, furacilin, cefazolin, etc.; it can also be used in the production of pesticides and fungicides, such as dozens of pesticides like paclobutrazol and ioxynil. In addition, due to the strong reducibility of hydrazine hydrate and the non-toxic and non-corrosive characteristics of its reaction products with oxygen, it can also be used as an oxygen scavenger for boiler water. Anhydrous hydrazine is a good propellant; the current rocket propellants in use include anhydrous hydrazine, monomethylhydrazine, and unsymmetrical dimethylhydrazine, which are mainly used as bipropellant fuels for rockets and also as monopropellants for satellites and spacecraft.

[0003] According to the development history of synthetic processes, the main methods for producing hydrazine hydrate at home and abroad are the following four: Raschig process (NaOH - Cl2 - NH3), urea process (NaOH - Cl2 - Urea), Bayer - ketazine process (ketone - NH3 - Cl2), hydrogen peroxide - ketazine process (ketone - NH3 - H2O2), and molecular oxygen - ketazine process (ketone - NH3 - O2). Among several relatively advanced methods for preparing hydrazine hydrate, such as the Bayer - ketazine process, hydrogen peroxide - ketazine process, and molecular oxygen - ketazine catalytic oxidation process, hydrazine hydrate is prepared by hydrolyzing the ketazine intermediate. Under the action of an acidic catalyst, the obtained ketazine reacts with water to generate hydrazine hydrate and a ketone compound, and the ketone compound can react with ammonia to form imine and be reused for the production of ketazine. The whole process is clean and efficient, overcoming the drawbacks of the traditional Raschig process. Among them, the Bayer process uses chlorine or sodium hypochlorite as the oxidant, producing a large amount of salt as a by - product, which causes relatively large environmental pollution; the product cost of the hydrogen peroxide - ketazine process is restricted by the price of hydrogen peroxide, and the investment cost is higher than that of the Bayer process. At the same time, this technology is monopolized by foreign countries.

[0004] The oxygen - ketazine method using a ketone as an ammonia carrier and oxygen as a raw material and oxidant is the most promising method for industrial production of hydrazine hydrate. Currently, the method of catalytic oxidative coupling of imine with oxygen to synthesize ketazine using homogeneous catalysts such as cuprous chloride has a relatively high reaction temperature, and nitrogen - containing ligands such as pyridine need to be added to the system to stabilize the metal copper salt. The reaction system requires extraction and recovery of the catalyst with a dilute hydrochloric acid solution, and there are drawbacks such as difficult separation and recovery of the catalyst and difficulty in industrial scale - up. Summary of the Invention

[0005] The purpose of the present disclosure is to provide a method for preparing ketazine by imine oxidation with oxygen and a method for preparing hydrazine hydrate. This method uses a metal-containing hierarchical porous molecular sieve catalytic material with highly dispersed active components, good accessibility, high thermal stability and chemical stability. When performing the imine oxidation coupling reaction to prepare ketazine, no additional base and ligand need to be added, and high imine conversion and ketazine selectivity can be obtained under mild conditions.

[0006] To achieve the above object, the first aspect of the present disclosure provides a method for preparing ketazine by imine oxidation with oxygen, which includes the following steps: under oxygen conditions, contacting an imine compound with a catalyst for an oxidation reaction; the catalyst is a composite catalytic material, and the composite catalytic material includes a pure silica molecular sieve and a metal element M dispersed in the intracrystalline of the pure silica molecular sieve; the metal M is selected from one or more of manganese, iron, cobalt, nickel, palladium, platinum, copper and gold.

[0007] Optionally, the composite catalytic material has the following IR-OH characteristics:

[0008] Denote the peak intensity of the highest peak in the wavenumber range of 3730 - 3740 cm -1 in the IR-OH spectrum of the composite catalytic material as I1; denote the peak intensity of the highest peak in the wavenumber range of 3730 - 3740 cm -1 in the IR-OH spectrum of the pure silica molecular sieve without the metal element M as I2,

[0009] I0 defined by the following formula (1) is any value between 0.20 and 0.98;

[0010] I0 = I1 / I2 formula (1);

[0011] Preferably, the value of I0 is any value between 0.36 and 0.98.

[0012] Optionally, the method further includes: mixing the imine compound with a solvent and then contacting it with the catalyst;

[0013] Preferably, the general formula of the imine compound is the structure shown in the following formula (1)

[0014]

[0015] R, R', and R'' are each independently selected from alkyl groups with 1 - 10 carbon atoms or aryl derivatives with 6 - 12 carbon atoms;

[0016] Optionally, the solvent includes one or more of methanol, 1,2-dichloroethane, chloroform, and acetonitrile;

[0017] Optionally, the molar ratio of the imine compound to the solvent is 1:(20 - 200), preferably 1:(20 - 100).

[0018] Optionally, the conditions for the oxidation reaction include: the reaction temperature is 40 - 100°C, preferably 60 - 90°C; the time is 1 - 48 h, preferably 2 - 24 h; the oxygen pressure is 0.1 - 0.5 MPa, preferably 0.1 - 0.3 MPa;

[0019] Optionally, the weight ratio of the catalyst to the imine compound is 1:(1 - 20); preferably 1:(1.9 - 10);

[0020] Optionally, the reactor for the oxidation reaction includes any one of a batch reactor, a fixed - bed reactor, a moving - bed reactor, a suspension reactor, and a slurry reactor.

[0021] Optionally, the all - silica molecular sieve in the composite catalytic material is at least one of an MFI - structure molecular sieve, an MEL - structure molecular sieve, a BEA - structure molecular sieve, an MWW - structure molecular sieve, a two - dimensional hexagonal - structure molecular sieve, a MOR - structure molecular sieve, and a TUN - structure molecular sieve; preferably one or more selected from an MFI - structure molecular sieve, an MEL - structure molecular sieve, a BEA - structure molecular sieve, an MCM - structure molecular sieve, and an SBA - structure molecular sieve; more preferably one or more of an MFI - structure molecular sieve, an MEL - structure molecular sieve, and a BEA - structure molecular sieve.

[0022] Optionally, in the composite catalytic material, the molar ratio of the metal element M to the silicon element is (0.001 - 0.2):1, preferably (0.001 - 0.16):1.

[0023] Optionally, the BET specific surface area of the composite catalytic material is 400 - 800 m 2 / g, the total pore volume is 0.3 - 0.65 mL / g, the micropore volume is 0.1 - 0.19 mL / g, and the mesopore volume is 0.2 - 0.46 mL / g; the metal element M in the composite catalytic material exists in the form of metal nanoparticles, and the average particle size of the metal nanoparticles is 0.5 - 8 nm.

[0024] Optionally, the catalyst is prepared by a preparation method including the following steps:

[0025] S1. Mix a template agent, a silicon source, water, a metal M precursor, a dendrimer, and a silylating agent to obtain a reaction mixture;

[0026] S2. Perform hydrothermal crystallization treatment and calcination treatment on the reaction mixture.

[0027] Optionally, in step S1, the molar ratio of the silicon source calculated as SiO2: template agent: water: metal M element: silanization reagent is 1: (0.005 to 1): (10 to 80): (0.001 to 0.2): (0.015 to 0.4), preferably 1: (0.005 to 1): (10 to 80): (0.001 to 0.16): (0.015 to 0.3); the molar ratio of the mass of the dendrimer to 10 times the amount of substance of the silicon source calculated as SiO2 is (0.01 - 3): 1, preferably (0.05 - 1): 1.

[0028] Optionally, step S1 includes:

[0029] a. Mix the template agent, silicon source and water to obtain a hydrolysis solution of silicon;

[0030] b. Add the dendrimer to the aqueous solution of the metal M precursor, and after mixing, obtain a first mixed material; mix the first mixed material and the hydrolysis solution of silicon to obtain a second mixed material;

[0031] c. Add the silanization reagent to the second mixed material, and after mixing, obtain the reaction mixture; preferably, the mixing conditions in step c include: stirring at 20 - 80 °C for 0.5 - 2 hours.

[0032] Optionally, in step S1, the silicon source is selected from at least one of organosilicone grease, solid silica gel, white carbon black and silica sol; preferably selected from at least one of organosilicone grease, solid silica gel and white carbon black; more preferably organosilicone grease, and the general formula of the organosilicone grease is the structure shown in the following formula (A):

[0033]

[0034] wherein R a 、R b 、R c 、R d are each independently selected from alkyl groups having 1 to 6 carbon atoms, and the alkyl groups are branched or straight-chain alkyl groups; preferably, R a 、R b 、R c 、R d are each independently selected from straight-chain alkyl groups having 1 to 4 carbon atoms or branched-chain alkyl groups having 3 to 4 carbon atoms; more preferably, the R a 、R b 、R c 、R d are each independently selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl or tert-butyl; more preferably, the organosilicone grease is selected from one or more of tetramethyl silicate, tetraethyl silicate, tetrabutyl silicate and dimethyldiethyl silicate.

[0035] Optionally, in step S1, the templating agent is an organic base, preferably at least one selected from quaternary ammonium bases, aliphatic amines, and aliphatic alkanolamines; more preferably, the templating agent is at least one selected from quaternary ammonium bases having the structure shown by the following general formula (B):

[0036] R1, R2, R3, and R4 are each independently selected from alkyl groups having 1 to 4 carbon atoms, preferably straight-chain alkyl groups having 1 to 4 carbon atoms and branched-chain alkyl groups having 3 to 4 carbon atoms, and more preferably R1, R2, R3, and R4 are each independently selected from at least one of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, and tert-butyl;

[0037] More preferably, the molecular sieve of the composite catalytic material is an MFI-type molecular sieve, and the templating agent is tetrapropylammonium hydroxide or a mixture composed of tetrapropylammonium hydroxide and one or more selected from tetrapropylammonium chloride and tetrapropylammonium bromide; or

[0038] the molecular sieve of the composite catalytic material is an MEL-type molecular sieve, and the templating agent is tetrabutylammonium hydroxide or a mixture composed of tetrabutylammonium hydroxide and one or more selected from tetrabutylammonium chloride and tetrabutylammonium bromide; or

[0039] the molecular sieve of the composite catalytic material is a BEA-type molecular sieve, and the templating agent is tetraethylammonium hydroxide or a mixture composed of tetraethylammonium hydroxide and one or more selected from tetraethylammonium chloride and tetraethylammonium bromide.

[0040] Optionally, in step a, the silicon source is an organosilicon grease. After mixing the templating agent, the organosilicon grease, and water, a hydrolysis and alcohol-evaporation treatment is further included to obtain a hydrolyzed solution of silicon;

[0041] Optionally, the conditions of the hydrolysis and alcohol-evaporation treatment include: stirring and hydrolyzing at 0 to 95 °C for 2 to 10 hours; preferably stirring and hydrolyzing at 50 to 95 °C for 2 to 8 hours.

[0042] Optionally, in step S1, the metal M precursor is one or more of an inorganic metal compound and an organic metal compound; the inorganic metal compound is a water-soluble inorganic salt of metal M; the water-soluble inorganic salt of metal M is selected from one or more of a chloride, a hydrated chloride, a sulfate, a hydrated sulfate, and a nitrate of metal M; the organic metal compound is an organic ligand compound of metal M; preferably the metal M precursor is a water-soluble inorganic salt of metal M;

[0043] The metal M is selected from one or more of manganese, iron, cobalt, nickel, palladium, platinum, copper, and gold;

[0044] Preferably, the metal M precursor is an aqueous solution of the metal M precursor, and the molar ratio of the metal M element to water in the aqueous solution of the metal M precursor is 1:(50-500).

[0045] Optionally, in step S1, the general formula of the silylating agent is R5Si(R6)(R7)R8, where R5, R6, R7, and R8 are each independently a halogen, an alkyl group, an alkoxy group, an aryl group, a mercapto group, or an amino group, and at least one of R5, R6, R7, and R8 is an alkyl group, an alkoxy group, an aryl group, a mercapto group, or an amino group; the number of carbon atoms of the alkyl group, alkoxy group, mercapto group, and amino group is each independently 1-18 carbon atoms, and the number of carbon atoms of the aryl group is 6-18;

[0046] Preferably, the silylating agent is selected from one or more of dimethyldichlorosilane, N-phenyl-3-aminopropyltrimethoxysilane, phenyltrimethoxysilane, 1,7-dichlorooctamethyltetrasiloxane, cetyltrimethoxysilane, octyltriethoxysilane, 3-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, and 3-mercaptopropyltrimethoxysilane; more preferably, at least one of N-phenyl-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, and 3-mercaptopropyltrimethoxysilane.

[0047] Optionally, in step S1, the dendrimer is selected from polyamide-amine macromolecules and polyarylether macromolecules;

[0048] Preferably, the polyamide-amine macromolecules are selected from one or more of generation 2 PAMAM with an ethylenediamine core, generation 3 PAMAM with an ethylenediamine core, and generation 4 PAMAM with an ethylenediamine core; the polyarylether macromolecules are selected from one or more of polyarylether nitrile, polyarylether sulfone, and polyarylether ketone; preferably, the weight average molecular weight of the dendrimer is 4000-85000, the viscosity at 30 °C is 0.025-0.045 dL / g, and the degree of branching is 4000-18000.

[0049] Optionally, in step S2, the conditions for the hydrothermal crystallization treatment include: under autogenous pressure conditions, the hydrothermal crystallization time is 0.5-10 days, and the hydrothermal crystallization temperature is 110-200 °C; preferably, the hydrothermal crystallization time is 0.5-5 days, and the hydrothermal crystallization temperature is 150-200 °C;

[0050] Optionally, the conditions for the calcination treatment include: the calcination temperature is 400-900 °C, and the calcination time is 1-16 hours; preferably, the calcination temperature is 400-800 °C, and the calcination time is 2-8 hours.

[0051] The second aspect of the present disclosure provides a method for preparing hydrazine hydrate, which includes the following steps: S1. Prepare ketazine by using the method described in the first aspect of the present disclosure; S2. Contact the ketazine with water for hydrolysis reaction.

[0052] Through the above technical solution, the present disclosure provides a method for preparing ketazine by imine oxidation with oxygen and a method for preparing hydrazine hydrate. This method uses a metal-containing hierarchical porous molecular sieve composite catalytic material as the catalyst for the imine oxidation coupling reaction to prepare ketazine. This composite catalytic material has a large specific surface area, pore volume, and reactivity towards macromolecular substrates, and the metal nanoparticles have a high dispersion degree in the molecular sieve. No additional base and ligand need to be added during the reaction process, and high conversion rate and ketazine selectivity can be obtained at a relatively low temperature.

[0053] Other features and advantages of the present disclosure will be described in detail in the subsequent specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] The drawings are used to provide a further understanding of the present disclosure, and constitute a part of the specification. They are used to explain the present disclosure together with the following specific implementation, but do not constitute a limitation to the present disclosure. In the drawings:

[0055] Figure 1 It is the IR-OH spectrum of the product prepared in Example 1 of the present disclosure.

[0056] Figure 2 It is the XRD spectrum of the product prepared in Example 1 of the present disclosure.

[0057] Figure 3 It is the SEM spectrum of the product prepared in Example 1 of the present disclosure. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0058] The following provides a detailed description of the specific implementation of the present disclosure. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0059] The first aspect of the present disclosure provides a method for preparing ketazine by imine oxidation with oxygen, which includes the following steps:

[0060] Under oxygen conditions, contact the imine compound with the catalyst for an oxidation reaction;

[0061] The catalyst is a composite catalytic material, and the composite catalytic material includes a pure silica molecular sieve and a metal element M dispersed in the intracrystalline of the pure silica molecular sieve; the metal M is selected from one or more of manganese, iron, cobalt, nickel, palladium, platinum, copper, and gold.

[0062] In the present disclosure, "pure all-silica molecular sieve" refers to an all-silica molecular sieve that does not contain other metal elements.

[0063] In the IR-OH spectra of the composite catalytic material and the pure all-silica molecular sieve described in the present disclosure, the peak intensity of the highest peak in the wavenumber range of 3730-3740 cm -1 can be the value obtained after the same normalization calculation. The normalization method is a method commonly used in the art.

[0064] The inventors of the present disclosure unexpectedly found that using a composite catalytic material of metal nanoparticles and a molecular sieve as a catalyst, under the action of this catalyst, the oxidation reaction of imine compounds can be carried out without adding a base and an additional ligand, which can effectively improve the oxidation reaction rate, shorten the reaction time, and achieve high conversion of imine and high selectivity of ketazine at a lower temperature.

[0065] In a preferred embodiment, the composite catalytic material has the following IR-OH characteristics:

[0066] Denote the peak intensity of the highest peak in the wavenumber range of 3730-3740 cm -1 in the IR-OH spectrum of the composite catalytic material as I1; denote the peak intensity of the highest peak in the wavenumber range of 3730-3740 cm -1 in the IR-OH spectrum of the all-silica molecular sieve without metal element M as I2.

[0067] I0 defined by the following formula (1) is any value between 0.20 and 0.98;

[0068] I0 = I1 / I2 formula (1);

[0069] The molecular sieve of the composite catalytic material has a large specific surface area, pore volume and reactivity towards macromolecular substrates; and the molecular sieve of this composite catalytic material has a hierarchical pore structure, the metal oxide nanoparticles have uniform particle sizes and are uniformly dispersed in the mesoporous channels of the hierarchical pore molecular sieve; this composite catalytic material has high catalytic activity in the process of preparing ketazine by imine oxidation.

[0070] The inventors of the present disclosure surprisingly found in a large number of experimental studies that when a metal precursor, a dendrimer and a silanizing reagent are introduced during the synthesis of the molecular sieve, after the reaction mixture is hydrothermally crystallized, washed and calcined, the obtained composite catalytic material including an all-silica molecular sieve and metal M oxide nanoparticles not only has large specific surface area and pore volume properties, the metal oxide nanoparticles have uniform particle sizes and are uniformly dispersed in the molecular sieve crystal (such as in the mesoporous channels of the molecular sieve), but may also exist on the surface of the molecular sieve pores; in addition, the inventors further found that the obtained composite catalytic material has 3730-3740 cm in the infrared hydroxyl (IR-OH) spectrum test -1The peak intensity (I1) of the highest peak within the range is lower than the peak intensity (I2) of the highest peak in the IR-OH spectrum of the all-silica molecular sieve without the metal element M within the wavenumber range of 3730-3740 cm -1 That is, the intensity of the terminal hydroxyl group is lower; and the ratio between I1 and I2 is related to the catalytic performance of the composite catalytic material. Especially when I0 (I0 = I1 / I2) is within the range of 0.20-0.98, the composite catalytic material has good catalytic activity during the oxidation of imine compounds, and a higher imine conversion rate and high selectivity for ketazine can be obtained.

[0071] In the present disclosure, the infrared hydroxyl spectrum test for the composite catalytic material is carried out by a solid infrared hydroxyl spectrum test method, and the operation is carried out on a NICOLET 6700. The experimental steps are as follows: about 20 mg of the sample is pressed into a self-supporting sheet; the self-supporting sheet is placed in a reaction cell and purified under the conditions of a high vacuum of 1.0×10 -3 Pa and a temperature of 550 °C for 2 hours; wait for the temperature to drop to 150 °C and measure the infrared spectrum.

[0072] In a preferred embodiment, the value of I0 is any value between 0.36 and 0.98. When the I0 of the composite catalytic material is within this range, a higher imine conversion rate and ketazine selectivity can be achieved.

[0073] In one embodiment, the method further includes: mixing the imine compound with a solvent and then contacting it with the catalyst;

[0074] Preferably, the general formula of the imine compound is the structure shown in the following formula (1)

[0075]

[0076] R, R', and R'' are each independently selected from an alkyl group having 1 to 10 carbon atoms or an aryl derivative having 6 to 12 carbon atoms; the solvent includes one or more of methanol, 1,2-dichloroethane, chloroform, and acetonitrile; the molar ratio of the imine compound to the solvent is 1:(20-200), preferably 1:(20-100). In this preferred case, the oxidation reaction can be further promoted.

[0077] In one embodiment, the conditions of the oxidation reaction include: the reaction temperature is 40-100 °C, preferably 60-90 °C; the time is 1-48 h, preferably 2-24 h; the oxygen pressure is 0.1-0.5 MPa, preferably 0.1-0.3 MPa; the weight ratio of the catalyst to the imine compound is 1:(1-20); preferably 1:(1.9-10); in this preferred case, the oxidation reaction can be further promoted, the oxidation reaction rate can be effectively increased, and the imine conversion rate can be increased.

[0078] Optionally, the reactor for the oxidation reaction includes any one of a tank reactor, a fixed-bed reactor, a moving-bed reactor, a suspension-bed reactor, and a slurry-bed reactor.

[0079] In one embodiment, the all-silica molecular sieve in the composite catalytic material is at least one of an MFI structure molecular sieve, an MEL structure molecular sieve, a BEA structure molecular sieve, an MWW structure molecular sieve, a two-dimensional hexagonal structure molecular sieve, a MOR structure molecular sieve, and a TUN structure molecular sieve; preferably, it is one or more selected from an MFI structure molecular sieve, an MEL structure molecular sieve, a BEA structure molecular sieve, an MCM structure molecular sieve, and an SBA structure molecular sieve; more preferably, it is one or more of an MFI structure molecular sieve, an MEL structure molecular sieve, and a BEA structure molecular sieve.

[0080] In one embodiment, the composite catalytic material includes silicon element, metal element M, and oxygen element, and the molar ratio of metal element M to silicon element is (0.001 - 0.2):1, preferably (0.001 - 0.16):1.

[0081] In one embodiment, the BET specific surface area of the composite catalytic material is 400 - 800 m 2 / g, the total pore volume is 0.3 - 0.65 mL / g, the micropore volume is 0.1 - 0.19 mL / g, and the mesopore volume is 0.2 - 0.46 mL / g; the metal element M in the composite catalytic material exists in the form of metal nanoparticles, and the average particle size of the metal nanoparticles is 0.5 - 8 nm. The composite catalytic material in the present disclosure also has a hierarchical pore structure, which is beneficial to catalyze reaction substrates of different sizes.

[0082] In one embodiment, the catalyst is prepared by a preparation method including the following steps:

[0083] S1. Mix a template agent, a silicon source, water, a metal M precursor, a dendrimer, and a silanization reagent to obtain a reaction mixture;

[0084] S2. Perform hydrothermal crystallization treatment and calcination treatment on the reaction mixture.

[0085] The present disclosure introduces a metal precursor, a dendrimer, and a silanization reagent into the raw materials for synthesizing molecular sieve crystallization, which can simultaneously achieve the effects of highly dispersing metal oxide nanoparticles in the molecular sieve crystal and expanding the pores of the molecular sieve support layer, and prepare a hierarchical pore molecular sieve composite catalytic material with highly dispersed metal oxide nanoparticles.

[0086] In the present disclosure, on the one hand, metal ions in the reaction mixture complex with groups such as amino groups contained in the dendrimer to achieve the effect of dispersing and stabilizing the metal; at the same time, at least one coordination group (such as amino group, mercapto group, oxygen-containing coordination group, etc.) carried by the silylating reagent can also complex with metal ions to achieve the effect of fixing and dispersing the metal, so that the metal oxide nanoparticles in the zeolite pores obtained after hydrothermal crystallization and calcination have a high degree of dispersion; on the other hand, the alkyl chain of the silylating reagent also ensures the realization of the pore-expanding effect of the zeolite support layer of the synthesized composite catalytic material, and the dendrimer has a very large molecular volume and can play a good role in supporting and isolating during zeolite crystallization, so as to finally prepare a hierarchical pore all-silica zeolite composite catalytic material with highly dispersed metal nanoparticles.

[0087] In the present disclosure, the "pure all-silica zeolite" is a product obtained by using the same preparation method as the composite catalytic material (the same amount of reaction raw materials and reaction conditions, etc.), but without introducing the metal M precursor and the dendrimer during the reaction process.

[0088] In one embodiment, in step S1, the molar ratio of the silicon source calculated as SiO2: template agent: water: metal M element: silylating reagent is 1: (0.005 - 1): (10 - 80): (0.001 - 0.2): (0.015 - 0.4), preferably 1: (0.005 - 1): (10 - 80): (0.001 - 0.16): (0.015 - 0.3); the molar ratio of the mass of the dendrimer to the amount of substance of 10 times the silicon source calculated as SiO2 is (0.01 - 3): 1, preferably (0.05 - 1): 1. Specifically, the water used in step S1 can be the water commonly used in synthesizing zeolites, and deionized water is preferred to avoid the introduction of heteroatoms.

[0089] In a preferred embodiment, step S1 includes:

[0090] a. Mix the template agent, silicon source and water to obtain a silicon hydrolysis solution;

[0091] b. Add the dendrimer to the aqueous solution of the metal M precursor, and after mixing, obtain a first mixed material; mix the first mixed material and the silicon hydrolysis solution to obtain a second mixed material;

[0092] c. Add the silylating reagent to the second mixed material, and after mixing, obtain the reaction mixture; preferably, the mixing conditions in step c include: stirring at 20 - 80 °C for 0.5 - 2 hours.

[0093] In one embodiment, in step S1, 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; the general formula of the silicone grease is the structure shown in the following formula (A):

[0094]

[0095] Wherein R a 、R b 、R c 、R d are each independently selected from alkyl groups having 1 to 6 carbon atoms, and the alkyl groups are branched or straight-chain alkyl groups; preferably, R a 、R b 、R c 、R d are each independently selected from straight-chain alkyl groups having 1 to 4 carbon atoms or branched-chain alkyl groups having 3 to 4 carbon atoms. For example, R a 、R b 、R c 、R d are each independently methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, or tert-butyl; more preferably, R a 、R b 、R c 、R d are each independently methyl or ethyl.

[0096] In a preferred embodiment, the silicone grease is selected from one or more of tetramethyl silicate, tetraethyl silicate, tetrabutyl silicate, and dimethyldiethyl silicone grease.

[0097] According to the present disclosure, in step S1, the template agent is an organic base, preferably selected from at least one of quaternary ammonium bases, aliphatic amines, and aliphatic alkanolamines. Among them, the quaternary ammonium base can be an organic quaternary ammonium base; the aliphatic amine can be a compound formed by substituting at least one hydrogen in NH3 with an aliphatic hydrocarbon group (such as an alkyl group); the aliphatic alkanolamine can be a compound formed by substituting at least one hydrogen in various NH3 with a hydroxyl-containing aliphatic group (such as an alkyl group).

[0098] More preferably, the template agent is selected from at least one of quaternary ammonium bases having the structure shown in the following formula (B):

[0099] R1, R2, R3 and R4 are independently selected from alkyl groups having 1 to 4 carbon atoms, preferably straight-chain alkyl groups having 1 to 4 carbon atoms and branched-chain alkyl groups having 3 to 4 carbon atoms, more preferably R1, R2, R3 and R4 are independently selected from at least one of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl and tert-butyl.

[0100] The template agent is preferably at least one of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide (including various isomers of tetrapropylammonium hydroxide, such as tetra-n-propylammonium hydroxide and tetraisopropylammonium hydroxide) and tetrabutylammonium hydroxide (including various isomers of tetrabutylammonium hydroxide, such as tetra-n-butylammonium hydroxide and tetraisobutylammonium hydroxide).

[0101] In a preferred embodiment, the molecular sieve of the composite catalyst material is an MFI type molecular sieve, and the template agent is tetrapropylammonium hydroxide or a mixture of tetrapropylammonium hydroxide and one or more selected from tetrapropylammonium chloride and tetrapropylammonium bromide; or

[0102] The molecular sieve of the composite catalytic material is a MEL type molecular sieve, and the template agent is tetrabutylammonium hydroxide or a mixture of tetrabutylammonium hydroxide and one or more selected from tetrabutylammonium chloride and tetrabutylammonium bromide; or

[0103] The molecular sieve of the composite catalytic material is a BEA type molecular sieve, and the template agent is tetraethylammonium hydroxide or a mixture of tetraethylammonium hydroxide and one or more selected from tetraethylammonium chloride and tetraethylammonium bromide. The present disclosure can prepare molecular sieves of different structures by selecting different template agents.

[0104] In one embodiment, in step a, the silicon source is organic silicone grease, and after the template, the organic silicone grease and water are mixed, a hydrolysis and alcohol removal treatment is further performed to obtain a hydrolyzed solution of the silicon;

[0105] The conditions for the hydrolysis and alcohol removal treatment include: stirring and hydrolyzing at 0-95° C. for 2-10 hours; preferably stirring and hydrolyzing at 50-95° C. for 2-8 hours.

[0106] Preferably, the hydrolysis-alcohol removal treatment is performed so that the mass content of alcohol produced by hydrolysis of the obtained organic silicone grease in the hydrolysis solution of silicon is less than 10 ppm.

[0107] According to the present disclosure, the optional range of types of the metal precursor is relatively wide, and any substance containing the metal (such as a compound containing a metal element and / or a metal single substance) can achieve the purpose of the present disclosure.

[0108] In one embodiment, in step S1, the metal M precursor is one or more of an inorganic metal compound and an organometallic compound; the inorganic metal compound is a water-soluble inorganic salt of metal M; the water-soluble inorganic salt of metal M is selected from one or more of a chloride, a hydrated chloride, a sulfate, a hydrated sulfate, and a nitrate of metal M; the organometallic compound is an organometallic ligand compound of metal M; preferably, the metal M precursor is a water-soluble inorganic salt of metal M;

[0109] The metal M is selected from one or more of manganese, iron, cobalt, nickel, palladium, platinum, copper, and gold;

[0110] Preferably, the metal M precursor is an aqueous solution of the metal M precursor, and the molar ratio of the metal M element to water in the aqueous solution of the metal M precursor is 1:(50 - 500).

[0111] In one embodiment, in step S1, the general formula of the silylating agent is R5Si(R6)(R7)R8, where R5, R6, R7, and R8 are each independently a halogen, an alkyl group, an alkoxy group, an aromatic group, a mercapto group, or an amino group, and at least one of R5, R6, R7, and R8 is an alkyl group, an alkoxy group, an aromatic group, a mercapto group, or an amino group; the number of carbon atoms of the alkyl group, the alkoxy group, the mercapto group, and the amino group is each independently 1 - 18, preferably 1 - 12; the number of carbon atoms of the aromatic group can be 6 - 18, preferably 6 - 12;

[0112] Preferably, the silylating agent is selected from one or more of dimethyldichlorosilane, N-phenyl-3-aminopropyltrimethoxysilane, phenyltrimethoxysilane, 1,7-dichlorooctamethyltetrasiloxane, cetyltrimethoxysilane, octyltriethoxysilane, 3-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, and 3-mercaptopropyltrimethoxysilane; more preferably, it is at least one of N-phenyl-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, and 3-mercaptopropyltrimethoxysilane.

[0113] In one embodiment, in step S1, the dendrimer is selected from polyamide-amine dendrimers, phenylacetylene dendrimers, polyarylether dendrimers, and polyarylester dendrimers.

[0114] In a preferred embodiment, the polyamide-amine dendrimers are selected from one or more of PAMAM (ethylenediamine core, generation 2), PAMAM (ethylenediamine core, generation 3), and PAMAM (ethylenediamine core, generation 4);

[0115] The polyarylether dendrimers are selected from one or more of polyarylether nitrile, polyarylether sulfone, and polyarylether ketone;

[0116] Preferably, the dendrimer has a molecular weight of 4,000 to 85,000, an intrinsic viscosity at 30 °C of 0.025 to 0.045 dL / g, a kinematic viscosity of 10 to 10,000 mm 2 / s, and a degree of branching of 4,000 to 18,000 (relative molecular weight, Mw).

[0117] In one embodiment, in step S2, the conditions of the hydrothermal crystallization treatment include: under autogenous pressure conditions, the hydrothermal crystallization time is 0.5 to 10 days, and the hydrothermal crystallization temperature is 110 to 200 °C; preferably, the hydrothermal crystallization time is 0.5 to 5 days, and the hydrothermal crystallization temperature is 150 to 200 °C.

[0118] In one embodiment, in step S2, the conditions of the calcination treatment include: the calcination temperature is 400 to 900 °C, and the calcination time is 1 to 16 hours; preferably, the calcination temperature is 400 to 800 °C, and the calcination time is 2 to 8 hours.

[0119] The second aspect of the present disclosure discloses a method for preparing hydrazine hydrate, which includes the following steps:

[0120] S1. Prepare ketazine by the method described in the first aspect;

[0121] S2. Contact ketazine with water to carry out a hydrolysis reaction.

[0122] In one embodiment, the conditions of the hydrolysis reaction include: the hydrolysis temperature is 70 - 100 °C, and the hydrolysis time is 4 - 8 h.

[0123] The ketazine described in the present disclosure undergoes a hydrolysis reaction to generate hydrazine hydrate and a ketone compound, and the ketone compound can also react with ammonia to generate imine, which is reused for the preparation of ketazine.

[0124] In the present disclosure, the X-ray diffraction (XRD) phase diagram of the sample is measured on a Siemens D5005 type X-ray diffractometer, the radiation source is Kα (Cu), and the test range of 2θ is 0.5° to 70°.

[0125] The Fourier transform infrared (FT-IR) spectrum of the sample is measured on a Nicolet 8210 type Fourier transform infrared spectrometer, and the test range is 400 to 4000 cm -1 .

[0126] The scanning electron microscope image SEM of the sample is obtained on a Hitachi S4800 high-resolution cold field emission scanning electron microscope.

[0127] The total specific surface area and total pore volume of the samples were measured on a Micromeritics ASAP 245 static nitrogen adsorption instrument according to the standard method ASTM D4222-98. The adsorption isotherm and desorption isotherm of low-temperature nitrogen adsorption of the samples were measured according to the standard method ASTM D4222-98.

[0128] The following further details the present disclosure through examples.

[0129] In the present disclosure, the infrared hydroxyl test steps are as follows: press the sample into a self-supporting sheet; place the sample sheet into the reaction cell and purify it for 2 hours under the conditions of a high vacuum of 1.0×10 -3 Pa and a temperature of 550 °C; lower the temperature to 150 °C and measure the infrared spectrum on a NICOLET 6700, with the wavenumber range of 400 - 4000 cm -1 .

[0130] In the following examples, among the dendrimers used, PAMAM is a polyamide-amine type dendritic polymer, purchased from InnoChem. The molecular weight of PAMAM (ethylenediamine core, generation 2) is 9858, the intrinsic viscosity at 30 °C is 0.037 dL / g, and the degree of branching is 4300 (Mw); the molecular weight of PAMAM (ethylenediamine core, generation 3) is 9858, the intrinsic viscosity at 30 °C is 0.035 dL / g, and the degree of branching is 5200 (Mw); the molecular weight of PAMAM (ethylenediamine core, generation 4) is 26000, the intrinsic viscosity at 30 °C is 0.031 dL / g, and the degree of branching is 16000 (Mw); the polyarylether macromolecule is purchased from InnoChem, and the molecular weight of polyarylether nitrile is 83000. In the present disclosure, the weight-average molecular weight of the dendrimer is obtained by an Ubbelohde viscometer and conventional methods; the degree of branching is obtained from the reagent label. The intrinsic viscosity is measured by an Ubbelohde viscometer using conventional methods.

[0131] In the following examples of the present disclosure, all cobalt nitrates used are cobalt(II) nitrate hexahydrate.

[0132] Preparation Example 1

[0133] (1) Add 1.6 g of an aqueous solution of tetrapropylammonium hydroxide (TPAOH) with a concentration of 25.05 wt%, 20.8 g of tetraethyl orthosilicate, and 52.8 g of water to a 500 mL beaker in sequence, place it on a magnetic stirrer with heating and stirring functions, mix evenly, and stir at 50 °C for 2 hours, and regularly supplement the evaporated water to obtain a colorless and transparent silica solution;

[0134] (2) Stir 0.03 g of copper(II) nitrate hexahydrate and 0.18 g of water evenly, then add 0.05 g of PAMAM (ethylenediamine core, generation 2), and mix the aqueous solution of copper with the hydrolyzed solution of silicon obtained in step (1);

[0135] (3) Add 0.64 g of N-phenyl-3-aminopropyltrimethoxysilane (PHAPTMS) to the mixture in step (2), and stir for 0.5 hour.

[0136] (4) Transfer the mixture obtained in step (3) to a stainless-steel sealed reactor, crystallize it at a constant temperature of 175 °C for 24 h to obtain a sample. Filter and wash the obtained sample, dry it at 110 °C for 6 hours, and then calcine it in a muffle furnace at 550 °C for 6 hours to obtain a metal nanoparticle and molecular sieve composite catalytic material product, denoted as CAT-1; its infrared hydroxyl spectrum is as Figure 1 shown. Among them, the peak at 3734 cm -1 represents the intensity of terminal hydroxyl defects; its BET specific surface area is 494 m 2 / g, the total pore volume is 0.376 mL / g; the micropore volume is 0.122 mL / g, and the mesopore volume is 0.254 mL / g.

[0137] The pure all-silica molecular sieve corresponding to Preparation Example CAT-1 was prepared through the following steps: Prepare the corresponding product according to the method of Example 1. The difference from Example 1 is that no metal element precursor and dendritic macromolecule are added. Other conditions and operations refer to Example 1.

[0138] The peak intensity of the highest peak in the range of 3730 - 3740 cm -1 of the infrared hydroxyl spectrum of this pure all-silica molecular sieve is 0.048.

[0139] Preparation Examples 2 - 9

[0140] Prepare the corresponding products according to the method of Example 1, denoted as CAT-2 - CAT-9. Their ratios, synthesis conditions, and results are shown in Table 1. The average particle sizes of the metal nanoparticles, BET specific surface areas, total pore volumes, micropore volumes, and mesopore volumes of CAT-2 - CAT-9 are listed in Table 2.

[0141] Preparation Example 10

[0142] In this example, a metal-containing hierarchical pore β molecular sieve, denoted as CAT-10, was prepared. Referring to the method of Example 1, change the ratio and template agent. The template agent used is tetraethylammonium hydroxide (TEAOH), denoted as CAT-10. Its ratio, synthesis conditions, and results are shown in Table 1.

[0143] Preparation Example 11

[0144] In this example, a metal-containing hierarchical pore MEL molecular sieve, denoted as CAT-11, was prepared. Referring to the method of Example 1, change the ratio and template agent. The template agent used is tetrabutylammonium hydroxide (TBAOH), denoted as CAT-11. Its ratio, synthesis conditions, and results are shown in Table 1.

[0145] Preparation Example 12

[0146] The corresponding product was prepared according to the method of Example 1, denoted as CAT-12. Its formulation ratio, synthesis conditions and results are listed in Table 1. Other conditions and operations refer to Example 1.

[0147] Among them, the hydrothermal crystallization temperature was 120 °C and the hydrothermal crystallization time was 6 days; the calcination temperature was 880 °C and the calcination time was 10 h.

[0148] Preparation of Comparative Example 1

[0149] This example was prepared according to the method of Example 1, except that the silylating reagent was not added. The obtained product was denoted as DCAT-1.

[0150] Preparation of Comparative Example 2

[0151] 0.03 g of copper(II) nitrate hexahydrate and 0.18 g of water were stirred evenly to obtain an aqueous solution of copper. Then 10.2 g of alumina support (Innochem product number A17263) was added and stirred for 4 h. The solvent was evaporated to dryness, the solid was collected, dried at 110 °C for 6 hours, and then calcined in a muffle furnace at 550 °C for 6 hours. The obtained product was denoted as DCAT-2.

[0152] Preparation of Comparative Example 3

[0153] 0.03 g of copper(II) nitrate hexahydrate and 0.18 g of water were stirred evenly to obtain an aqueous solution of copper. Then 6 g of all-silica MFI zeolite support was added and stirred for 4 h. The solvent was evaporated to dryness. The solid was collected and dried at 110 °C for 6 hours, and then calcined in a muffle furnace at 550 °C for 6 hours. The obtained product was denoted as DCAT-3. The preparation process of the all-silica MFI zeolite is referred to Preparation Example 1. The difference from Preparation Example 1 is that cobalt(II) nitrate hexahydrate and dendritic macromolecules were not introduced during the zeolite synthesis process, and the rest of the process was the same as Preparation Example 1.

[0154] The preparation method of the pure all-silica zeolite corresponding to the composite catalytic materials prepared in Preparation Examples 2 to 12 was referred to Preparation Example 1, except that the metal element precursor and dendritic macromolecule were not added during the preparation process of the corresponding composite catalytic materials.

[0155] The pure all-silica zeolites in the above preparation examples and comparative examples were prepared through the following steps: for the preparation of pure all-silica zeolites. The corresponding product was prepared according to the method of Example 1, different from Example 1 in that: the metal element precursor and dendritic macromolecule were not added. Other conditions and operations refer to Example 1.

[0156] The peak intensity of the highest peak in the infrared hydroxyl spectrum of this pure all-silica zeolite in the range of 3730 - 3740 cm -1 was 0.048.

[0157] The BET specific surface area, total pore volume, micropore volume, mesopore volume of the products obtained in the above preparation examples and comparative examples, and the average particle size of metal nanoparticles in the composite catalytic material are listed in Table 2 below.

[0158] Table 1

[0159]

[0160]

[0161] In m / 10×c*, m represents the mass of the dendrimer, and c represents the amount of substance of the silicon source calculated as SiO2.

[0162] In Table 1, TPAOH is tetrapropylammonium hydroxide, TPABr is tetrapropylammonium bromide, TBAOH is tetrabutylammonium hydroxide, and TEAOH is tetraethylammonium hydroxide; PHAPTMS is N-phenyl-3-aminopropyltrimethoxysilane, APTES is 3-aminopropyltriethoxysilane, and KH792 is silane coupling agent kh792 (bisamino-functional silane, N-aminoethyl-γ-aminopropyltrimethoxysilane); PAMAM is polyamide-amine macromolecule. The reagents used in the present disclosure can be obtained through conventional purchasing channels.

[0163] Table 2

[0164]

[0165] Among them, the pores with a diameter less than 2 nm are micropore diameters; the pores with a diameter between 2 and 50 nm are mesopores.

[0166] According to Table 2, compared with DCAT-1 (without adding silanization reagent), the composite catalytic materials CAT-1 to CAT-12 provided by the present disclosure have higher mesopore volume and lower particle size of metal nanoparticles, indicating that the method provided by the present disclosure can effectively expand the pores of the molecular sieve, and the aggregation degree of metal nanoparticles is lower and the dispersion degree is higher.

[0167] Compared with DCAT-2 and DCAT-3, the composite catalytic materials CAT-1 to CAT-12 provided by the present disclosure can simultaneously have a large mesopore volume, a large specific surface area and a smaller particle size of metal nanoparticles, indicating that the aggregation degree of metal nanoparticles in the composite catalytic materials obtained by the present disclosure is lower and the dispersion degree is higher.

[0168] Reaction Example 1

[0169] This reaction example is used to illustrate the use of the samples prepared in the above Examples 1-11 and Comparative Examples 1-3 for the catalytic oxidative dehydrogenation coupling of imines. 1 mmol of imine was mixed with 2.5 mL of 1,2-dichloroethane solvent (the molar ratio of imine to 1,2-dichloroethane was 1:30), and then contacted with 50 mg of the catalyst in a slurry bed reactor. The contact temperature was 80 °C, the time was 12 h, and the oxygen pressure was 0.1 MPa. The results are shown in Table 3 below.

[0170] Among them, the product distribution of each product was determined on an Agilent 6890N chromatograph using an HP-5 capillary column (30 m × 0.25 mm).

[0171] The calculation methods of the imine conversion rate (%) and the ketazine selectivity (%) are shown in the following formula:

[0172] Imine conversion rate (%) = number of moles of imine participating in the reaction / number of moles of imine added × 100%;

[0173] Ketazine selectivity (%) = (number of moles of ketazine × 2 / number of moles of imine participating in the reaction) × 100%

[0174] Among them, the number of moles of imine participating in the reaction = number of moles of imine fed - number of moles of imine remaining in the resulting reaction mixture.

[0175] Table 3

[0176]

[0177] According to the data in Table 3, compared with DCAT-1 to DCAT-4, the I0 of the composite catalytic materials CAT-1 to CAT-12 prepared in Examples 1 to 12 of the present disclosure is in the range of 0.20 to 0.98. This composite catalytic material has higher catalytic activity, higher imine conversion rate and higher ketazine selectivity.

[0178] By comparing CAT-1 to CAT-12, it can be seen that compared with CAT-12, the I0 of CAT-1 to CAT-11 is in the range of 0.36 to 0.98. CAT-1 to CAT-11 have higher catalytic activity, higher imine conversion rate and higher ketazine selectivity.

[0179] Reaction Example 2

[0180] This test example is used to illustrate the reaction effects under different reaction conditions. The composite catalytic material CAT-9 was selected as the catalyst, and methylcyclohexylmethylimine was used as the raw material, and the catalyst dosage was 50 mg.

[0181] Referring to the operation process of Reaction Example 1, the reaction conditions were changed. The specific reaction conditions and reaction results are shown in Table 4 below.

[0182] Table 4

[0183]

[0184] As can be seen from Table 3 and Table 4, by comparing the catalytic effects obtained using CAT-9 in Reaction Example 2 and Reaction Example 1 of this reaction, it can be known that when the reaction temperature in Reaction Example 1 is in the range of 60-90 °C, the oxidation reaction effect is better, and the imine conversion rate and ketazine selectivity are higher.

[0185] Reaction Example 3

[0186] This reaction example is used to illustrate the preparation of hydrazine hydrate.

[0187] Taking the ketazine product formed by catalyzing diphenylmethanimine using CAT-1 in Reaction Example 1 as an example for illustration. The specific reaction conditions include: under strongly acidic conditions, adding ketazine and water, hydrolyzing at 80 °C for 8 hours, and neutralizing with alkali to obtain hydrazine hydrate.

[0188] The preferred embodiments of the present disclosure have been described in detail above. However, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept scope of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0189] In addition, it should be noted that, in the case of no contradiction, the various specific technical features described in the above specific embodiments can be combined in any suitable manner. To avoid unnecessary repetition, the present disclosure will not separately describe various possible combination methods.

[0190] Furthermore, any combination can be made between various different embodiments of the present disclosure, as long as it does not violate the idea of the present disclosure, and it should also be regarded as the content disclosed by the present disclosure.

Claims

1. A method for preparing ketazine by imine oxidation with oxygen, characterized in that, The method comprises the following steps: Under oxygen conditions, an imine compound is contacted with a catalyst for an oxidation reaction; The catalyst is a composite catalytic material, and the composite catalytic material comprises a silicalite molecular sieve and a metal element M dispersed in the intracrystalline of the silicalite molecular sieve; the metal M is selected from one or more of manganese, iron, cobalt, and copper; the composite catalytic material has a hierarchical pore structure; the metal element M in the composite catalytic material exists in the form of metal nanoparticles; The composite catalytic material has the following IR-OH characteristics: Record the peak intensity of the highest peak in the wavenumber range of 3730 - 3740 cm in the IR-OH spectrum of the composite catalytic material as I1; Record the peak intensity of the highest peak in the wavenumber range of 3730 - 3740 cm in the IR-OH spectrum of the all-silica molecular sieve without metal element M as I2, -1 Record the peak intensity of the highest peak in the wavenumber range of 3730 - 3740 cm in the IR-OH spectrum of the composite catalytic material as I1; Record the peak intensity of the highest peak in the wavenumber range of 3730 - 3740 cm in the IR-OH spectrum of the all-silica molecular sieve without metal element M as I2, -1 in the range as I2, I0 defined by the following formula (1) is any value between 0.20 and 0.98; I0 = I1 / I2 formula (1); The general formula of the imine compound is the structure shown in the following general formula (1) General formula (1); R, R’, and R’’ are each independently selected from alkyl groups having 1 to 10 carbon atoms or aryl derivatives having 6 to 12 carbon atoms; The silicalite molecular sieve in the composite catalytic material is at least one 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.

2. The method according to claim 1, wherein The value of I0 is any value between 0.36 and 0.

98.

3. The method according to claim 1, characterized in that, The method further comprises: mixing the imine compound with a solvent and then contacting it with the catalyst; The solvent includes one or more of methanol, 1,2-dichloroethane, chloroform, and acetonitrile; The molar ratio of the imine compound to the solvent is 1:(20 - 200).

4. The method according to claim 3, wherein The molar ratio of the imine compound to the solvent is 1:(20 - 100).

5. The method according to claim 1, characterized in that The conditions of the oxidation reaction include: the reaction temperature is 40 - 100 °C; the time is 1 - 48 h; the oxygen pressure is 0.1 - 0.5 MPa; The weight ratio of the catalyst to the imine compound is 1:(1 - 20).

6. The method according to claim 5, wherein The conditions of the oxidation reaction include: the reaction temperature is 60 - 90 °C; the time is 2 - 24 h; the oxygen pressure is 0.1 - 0.3 MPa; The weight ratio of the catalyst to the imine compound is 1:(1.9 - 10).

7. The method according to claim 5, characterized in that The reactor for the oxidation reaction includes any one of a batch reactor, a fixed-bed reactor, a moving-bed reactor, a suspension reactor, and a slurry reactor.

8. The method according to claim 1, wherein The silicalite molecular sieve in the composite catalytic material 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.

9. The method according to claim 8, characterized in that, The silicalite molecular sieve in the composite catalytic material is selected from one or more of MFI structure molecular sieve, MEL structure molecular sieve, and BEA structure molecular sieve.

10. The method according to claim 1, characterized in that, In the composite catalytic material, the molar ratio of the metal element M to the silicon element is (0.001 - 0.2):

1.

11. The method according to claim 10, characterized in that In the composite catalytic material, the molar ratio of the metal element M to the silicon element is (0.001 - 0.16):

1.

12. The method according to claim 1, wherein The BET specific surface area of the composite catalytic material is 400~800 m 2 / g, the total pore volume is 0.3~0.65 mL / g, the micropore volume is 0.1~0.19 mL / g, and the mesopore volume is 0.2~0.46 mL / g; the average particle size of the metal nanoparticles is 0.5~8 nm.

13. The method according to claim 1, wherein The catalyst is prepared by a preparation method comprising the following steps: S1. Mix a template agent, a silicon source, water, a metal M precursor, a dendritic macromolecule, and a silylating agent to obtain a reaction mixture; S2. Hydrothermally crystallize and calcine the reaction mixture.

14. The method according to claim 13, wherein In step S1, the molar ratio of the silicon source calculated as SiO2: template agent: water: metal M element: silanization reagent is 1: (0.005 - 1): (10 - 80): (0.001 - 0.2): (0.015 - 0.4); the molar ratio of the mass of the dendritic macromolecule to the amount of substance of 10 times the silicon source calculated as SiO2 is (0.01 - 3):

1.

15. The method according to claim 14, characterized in that, In step S1, the molar ratio of the silicon source calculated as SiO2: template agent: water: metal M element: silanization reagent is 1: (0.005 - 1): (10 - 80): (0.001 - 0.16): (0.015 - 0.3); the molar ratio of the mass of the dendritic macromolecule to the amount of substance of 10 times the silicon source calculated as SiO2 is (0.05 - 1):

1.

16. The method according to claim 13, wherein Step S1 includes: a. Mix the template agent, silicon source and water to obtain a silicon hydrolysis solution; b. Add the dendritic macromolecule to the aqueous solution of the metal M precursor, and after mixing, obtain a first mixed material; mix the first mixed material and the silicon hydrolysis solution to obtain a second mixed material; c. Add the silanization reagent to the second mixed material, and after mixing, obtain the reaction mixture.

17. The method according to claim 16, wherein The mixing conditions in step c include: stirring at 20 - 80 °C for 0.5 - 2 hours.

18. The method according to claim 13, characterized in that, In step S1, the silicon source is selected from at least one of organosilicon grease, solid silica gel, white carbon black and silica sol.

19. The method according to claim 18, characterized in that, The silicon source is selected from at least one of organosilicon grease, solid silica gel and white carbon black.

20. The method according to claim 19, wherein The silicon source is organosilicon grease, and the general formula of the organosilicon grease is the structure shown in the following formula (A): wherein R a , R b , R c , R d are each independently selected from alkyl groups having 1 to 6 carbon atoms, and the alkyl groups are branched or straight-chain alkyl groups.

21. The method according to claim 20, wherein In formula (A), 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-chain alkyl group having 3 to 4 carbon atoms.

22. The method according to claim 21, wherein In formula (A), the R a , R b , R c , R d are each independently selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl or tert-butyl.

23. The method according to claim 22, wherein The organosilicon grease is selected from one or more of tetramethyl silicate, tetraethyl silicate, tetrabutyl silicate and dimethyldiethyl silicate.

24. The method according to claim 13, wherein In step S1, the template agent is an organic base.

25. The method according to claim 24, wherein The template agent is selected from at least one of quaternary ammonium bases, aliphatic amines and aliphatic alkanolamines.

26. The method according to claim 25, characterized in that The template agent is selected from at least one of quaternary ammonium bases with the structure shown in the following formula (B): (B); R1, R2, R3 and R4 are each independently selected from alkyl groups having 1 to 4 carbon atoms.

27. The method according to claim 26, wherein In formula (B), R1, R2, R3 and R4 are each independently selected from straight-chain alkyl groups having 1 - 4 carbon atoms and branched-chain alkyl groups having 3 - 4 carbon atoms.

28. The method according to claim 27, characterized in that, In formula (B), R1, R2, R3 and R4 are each independently selected from at least one of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl and tert-butyl.

29. The method according to claim 13, wherein In step S1, the molecular sieve of the composite catalytic material is an MFI-type molecular sieve, and the template agent is tetrapropylammonium hydroxide or a mixture composed of tetrapropylammonium hydroxide and one or more of tetrapropylammonium chloride and tetrapropylammonium bromide; or The molecular sieve of the composite catalytic material is an MEL-type molecular sieve, and the template agent is tetrabutylammonium hydroxide or a mixture composed of tetrabutylammonium hydroxide and one or more of tetrabutylammonium chloride and tetrabutylammonium bromide; or The molecular sieve of the composite catalytic material is a BEA-type molecular sieve, and the template agent is tetraethylammonium hydroxide or a mixture composed of tetraethylammonium hydroxide and one or more of tetraethylammonium chloride and tetraethylammonium bromide.

30. The method according to claim 16, wherein In step a, the silicon source is silicone grease. After mixing the template agent, silicone grease and water, hydrolysis and alcohol removal treatment is further included to obtain the hydrolysis solution of silicon. The conditions of the hydrolysis and alcohol removal treatment include: stirring and hydrolyzing at 0~95 °C for 2~10 hours.

31. The method according to claim 30, wherein The conditions of the hydrolysis and alcohol removal treatment include: stirring and hydrolyzing at 50~95 °C for 2~8 hours.

32. The method according to claim 13, wherein In step S1, the metal M precursor is one or more of inorganic metal compounds and organic metal compounds; the inorganic metal compound is a water-soluble inorganic salt of metal M; the water-soluble inorganic salt of metal M is selected from one or more of chlorides, hydrated chlorides, sulfates, hydrated sulfates and nitrates of metal M; the organic metal compound is an organic ligand compound of metal M.

33. The method according to claim 32, wherein, The metal M precursor is a water-soluble inorganic salt of metal M. The metal M is selected from one or more of manganese, iron, cobalt and copper.

34. The method according to claim 32, wherein The metal M precursor uses an aqueous solution of the metal M precursor, and the molar ratio of the metal M element to water in the aqueous solution of the metal M precursor is 1:(50~500).

35. The method according to claim 13, wherein In step S1, the general formula of the silylating agent is R5Si(R6)(R7)R8, where R5, R6, R7, and R8 are each independently a halogen, an alkyl group, an alkoxy group, an aromatic group, a mercapto group or an amino group, and at least one of R5, R6, R7, and R8 is an alkyl group, an alkoxy group, an aromatic group, a mercapto group or an amino group; the number of carbon atoms of the alkyl group, alkoxy group, mercapto group and amino group is each independently 1~18 carbon atoms, and the number of carbon atoms of the aromatic group is 6~18.

36. The method according to claim 13, wherein The silylating agent is selected from one or more of dimethyldichlorosilane, N-phenyl-3-aminopropyltrimethoxysilane, phenyltrimethoxysilane, 1,7-dichlorooctamethyltetrasiloxane, hexadecyltrimethoxysilane, octyltriethoxysilane, 3-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane and 3-mercaptopropyltrimethoxysilane.

37. The method according to claim 36, characterized in that, The silylating agent is selected from at least one of N-phenyl-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane and 3-mercaptopropyltrimethoxysilane.

38. The method according to claim 13, characterized in that, In step S1, the dendrimer is selected from polyamide-amine macromolecules and polyarylether macromolecules.

39. The method according to claim 38, wherein The polyamide-amine macromolecules are selected from one or more of generation 2 PAMAM with an ethylenediamine core, generation 3 PAMAM with an ethylenediamine core and generation 4 PAMAM with an ethylenediamine core. The polyarylether macromolecules are selected from one or more of polyarylether nitrile, polyarylether sulfone and polyarylether ketone.

40. The method according to claim 39, wherein The weight-average molecular weight of the dendrimer is 4000~85000, the viscosity at 30 °C is 0.025~0.045 dL / g, and the degree of branching is 4000~18000.

41. The method according to claim 13, wherein In step S2, the conditions of the hydrothermal crystallization treatment include: under autogenous pressure conditions, the hydrothermal crystallization time is 0.5~10 days, and the hydrothermal crystallization temperature is 110~200 °C. The conditions of the calcination treatment include: the calcination temperature is 400~900 °C, and the calcination time is 1~16 hours.

42. The method according to claim 41, wherein The conditions for the hydrothermal crystallization treatment include: the hydrothermal crystallization time is 0.5 to 5 days, and the hydrothermal crystallization temperature is 150 to 200 °C; The conditions for the calcination treatment include: the calcination temperature is 400 to 800 °C, and the calcination time is 2 to 8 hours.

43. A method for preparing hydrazine hydrate, characterized in that, It includes the following steps: S1. Prepare ketazine by using the method described in any one of claims 1 to 42; S2. Contact ketazine with water for hydrolysis reaction.

44. The preparation method according to claim 43, characterized in that, The conditions for the hydrolysis reaction include: the hydrolysis temperature is 70 to 100 °C, and the hydrolysis time is 4 to 8 h.

Images