A process for the preparation of carboxylic acids by the oxidation of alcohols with oxygen

Abstract

The present disclosure relates to a method for preparing carboxylic acid by oxygen oxidation of alcohol, which comprises the following steps: contacting alcohol compound and olefin compound with a catalyst for oxidation reaction in the presence of oxygen; the catalyst is a composite catalytic material, which comprises a framework heteroatom molecular sieve and a metal element M dispersed in the intracrystalline of the molecular sieve; the framework heteroatom molecular sieve is a molecular sieve in which at least part of the silicon in the full-silicon molecular sieve framework is replaced by a heteroatom element Q, and the heteroatom element Q is one or more selected from titanium, boron, zirconium, tin, aluminum, phosphorus and germanium. The method can obtain high conversion of alcohol and high selectivity of carboxylic acid under relatively mild conditions by using a metal-containing hierarchical pore molecular sieve as a catalyst for preparing carboxylic acid by oxygen oxidation of alcohol.

Description

Technical Field

[0001] This disclosure relates to the field of organic chemical engineering, and more specifically, to a method for preparing carboxylic acids by oxidizing alcohols with oxygen. Background Technology

[0002] Carboxylic acids are an important class of organic compounds with wide applications in industry, agriculture, medicine, and daily life. The oxidation reaction from alcohols to acids is a fundamental and crucial chemical reaction in organic chemistry. In industry and pharmaceuticals, carboxylic acids are often produced through oxidation methods. Therefore, finding a highly efficient, inexpensive, mild, functionally compatible, and environmentally friendly catalytic oxidation system holds great promise.

[0003] Traditionally, acids are synthesized by oxidizing the corresponding alcohols using stoichiometric or excess oxidants, such as KMnO4 oxidation, Jones oxidation, and other CrO3-based oxidation methods. The disadvantages of these methods are that the oxidants contain heavy metals, are expensive, produce wastewater that pollutes the environment, often require strong acids, have demanding conditions, and require sophisticated equipment, making them unsuitable for large-scale industrial production.

[0004] Oxygen is an inexpensive, readily available, clean, highly atom-economical, and environmentally friendly oxidant. Air is an even more ideal oxidant, requiring no preparation or transportation and being safer in industrial production. Currently, methods for oxidizing alcohols to acids using oxygen as an oxidant are very limited and concentrated in the field of noble metal catalysis; reports of air oxidation are even rarer. For example, the Pt-catalyzed Heyns oxidation was developed in the 1940s; however, the high price and easy poisoning of Pt limited its industrial application. In 2014, Jiang Biao's group achieved the oxidation of benzyl alcohol to acid using dry air in an Ag(NHC) / KOH system. Davis et al. reported the Au / H2O interface catalysis of ethanol and glycerol to acid. Zhang Zehui et al. reported the oxygen oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid using supported magnetic Pd nanocatalysts. Buffin et al. reported that under Pd catalysis, alcohols can be oxidized by oxygen to a mixture of carboxylic acids and esters, and benzyl alcohol can be oxidized to a mixture of aldehydes and acids. In 2015, Li Chaojun's group reported the oxidation of aldehydes to acid by oxygen in an AgO2 / IPr system. Oxidation reactions catalyzed by metals such as Ag, Au, Ru, and Pd have also been reported, but these have strong substrate limitations and mostly require nanotechnology or supported substrates. TEMPO provides a stable oxygen free radical, which plays an important role in the co-catalytic oxidation of alcohols to aldehydes or ketones with Fe or Cu.

[0005] However, there have been no reports of oxygen oxidizing alcohols or aldehydes to produce acids in such systems. Summary of the Invention

[0006] The present disclosure aims to provide a method for preparing carboxylic acid by oxidizing alcohol with oxygen, which uses a composite catalytic material including a framework heteroatom molecular sieve and a metal element dispersed in the crystal of the molecular sieve as a catalyst, and can obtain high alcohol conversion rate and high acid selectivity in the alcohol oxygen oxidation reaction, and simultaneously produce by-product epoxy olefin.

[0007] To achieve the above-mentioned purpose, the present disclosure provides a method for preparing carboxylic acid by oxidizing alcohol with oxygen, which includes the following steps: contacting alcohol compounds and olefin compounds with a catalyst in the presence of oxygen to perform an oxidation reaction; the catalyst is a composite catalytic material, which includes a framework heteroatom molecular sieve and a metal element M dispersed in the crystal of the molecular sieve; the framework heteroatom molecular sieve is a molecular sieve in which at least part of the silicon in the full-silicon molecular sieve framework is replaced by a heteroatom element Q, and the heteroatom element Q is one or more selected from titanium, boron, zirconium, tin, aluminum, phosphorus and germanium.

[0008] Optionally, the alcohol compounds are selected from one or more of alkyl alcohol with carbon atom number of 6-12 and aryl alcohol with carbon atom number of 7-14;

[0009] Preferably, the alcohol compounds are selected from one or more of sec-butyl alcohol, cyclohexanol, hexanol, 2-methyl-1-butanol, 1-methylcyclopentanol, 2-hexyl-1-octanol, benzyl alcohol, 1-pentanol, n-octanol, 2-hexyl-1-octanol and 1-butanol;

[0010] Optionally, the olefin compounds are selected from one or more of aliphatic olefin with carbon atom number of 6-20;

[0011] Preferably, the method further includes: after mixing the alcohol with the olefin compounds, contacting the mixture with the catalyst to perform an oxidation reaction; the molar ratio of the alcohol reactant to the olefin reactant is 1:(0.5-5), preferably 1:(0.5-3).

[0012] Optionally, the oxidation reaction conditions include: the reaction temperature is 40-100℃, preferably 60-80℃; the time is 1-48h, preferably 2-24h; the oxygen pressure is 0.1-0.5MPa, preferably 0.1-0.3MPa;

[0013] Optionally, the weight ratio of the catalyst to the alcohol compounds is 1:(0.5-20), preferably 1:(0.5-10);

[0014] Optionally, the reactor for the oxidation reaction is any one of a tank reactor, a fixed bed reactor, a moving bed reactor, a suspended bed reactor and a slurry bed reactor.

[0015] Optionally, the metal element M is a metal element capable of forming stable oxide aggregates,

[0016] The composite catalytic material has the following XPS characteristics:

[0017] The electron binding energy of the metal element M in the composite catalytic material is denoted as T1;

[0018] The electron binding energy of the metal element M in the stable oxide aggregates is denoted as T2, and T0 defined by the following formula (1) is any value between 0.6 and 1.5 eV:

[0019] T0 = T1 - T2 Formula (1);

[0020] Preferably, T0 is any value between 0.8 and 1.5 eV.

[0021] Optionally, the framework heteroatom 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; preferably one or more selected from 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;

[0022] Optionally, the metal element M is selected from one or more of manganese, iron, cobalt, nickel, palladium, platinum, copper and gold;

[0023] Preferably, when the metal M is Co, the stable oxide aggregate is a Co3O4 aggregate;

[0024] When the metal M is Mn, the stable oxide aggregate is a MnO2 aggregate;

[0025] When the metal M is Fe, the stable oxide aggregate is a Fe2O3 aggregate;

[0026] When the metal M is Ni, the stable oxide aggregate is a NiO aggregate;

[0027] When the metal M is Pd, the stable oxide aggregate is a PdO aggregate;

[0028] When the metal M is Pt, the stable oxide aggregate is a PtO2 aggregate; or,

[0029] When the metal M is Cu, the stable oxide aggregate is a CuO aggregate;

[0030] Preferably, when the metal element M is Co, Mn, Fe, Ni or Cu, the electron binding energy of the metal element M is 2p of the metal element M 3 / 2 electron binding energy; when the metal element M is Au or Pt, the electron binding energy of the metal element M is 4f of the metal element M 7 / 2 electron binding energy; when the metal element M is Pd, the electron binding energy of the metal element M is 3d of the metal element M 5 / 2 electron binding energy.

[0031] Optionally, the composite catalytic material has a BET specific surface area of 400-800 m 2 / g, a total pore volume of 0.3-0.65 mL / g, a micropore volume of 0.1-0.19 mL / g, a mesopore volume of 0.2-0.46 mL / g, and the metal element M in the composite catalytic material exists in the form of metal nanoparticles with an average particle size of 0.5-5.5 nm.

[0032] Optionally, the catalyst is prepared by a preparation method comprising the following steps:

[0033] S1, mixing a template agent, a silicon source, a skeleton heteroatom precursor, water, a metal M precursor, a nitrogen-containing ligand and a silylation reagent to obtain a reaction mixture;

[0034] S2, performing hydrothermal crystallization treatment on the reaction mixture to obtain a crystallization product, and performing calcination treatment on the crystallization product;

[0035] Optionally, the silylation reagent comprises at least one coordination group complexed with the metal element M.

[0036] Optionally, the electron binding energy of the metal element M in the product of the calcination treatment of the crystallization product is denoted as T3;

[0037] The electron binding energy of the metal element M in the crystallization product is denoted as T4;

[0038] The calcination treatment makes T0' defined by the following formula (2) an arbitrary value between 0.4 and 0.8 eV;

[0039] T0'= T3- T4 Formula (2).

[0040] Optionally, the molar ratio of the silicon source: the template agent: the framework heteroatom precursor: water: the metal element M: the silylating agent in step S1 is 1: (0.001-1): (0.002-0.05): (5-100): (0.001-0.25): (0.015-0.4) in terms of SiO2; preferably 1: (0.001-1): (0.003-0.045): (5-100): (0.002-0.15): (0.025-0.3).

[0041] Preferably, the molar ratio of the nitrogen-containing ligand to the metal element M is (0.5-5): 1.

[0042] Optionally, step S1 comprises the following steps:

[0043] a. mixing the template agent, the silicon source, the framework heteroatom precursor and water to obtain a hydrolysis solution of silicon;

[0044] b. adding the nitrogen-containing ligand to the aqueous solution of the metal M precursor to obtain a first mixture; mixing the first mixture with the hydrolysis solution of silicon to obtain a second mixture;

[0045] c. adding the silylating agent to the second mixture, and mixing to obtain the reaction mixture;

[0046] Preferably, the mixing in step c. comprises stirring at 20-80°C for 0.5-2 hours.

[0047] Optionally, the silicon source is selected from at least one of organosilicon grease, solid silica gel, white carbon black and silica sol; preferably at least one of organosilicon grease, solid silica gel and white carbon black.

[0048] Further preferably, the organosilicon grease has a general formula as shown in the following formula (A):

[0049]

[0050] 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 c , Rd each independently selected from the group consisting of methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, iso-butyl, or tert-butyl; further preferably, the organosilicon ester is selected from one or more of tetramethyl silicate, tetraethyl silicate, tetrabutyl silicate, and dimethyldiethyl silicate.

[0051] Optionally, the template agent is an organic base, preferably at least one selected from the group consisting of quaternary ammonium base, aliphatic amine, and aliphatic alcohol amine; further preferably, the template agent is at least one selected from the group consisting of quaternary ammonium base of general formula (B):

[0052] wherein R1, R2, R3, and R4are each independently selected from the group consisting of alkyl having 1-4 carbon atoms, preferably linear alkyl having 1-4 carbon atoms and branched alkyl having 3-4 carbon atoms, more preferably R1, R2, R3, and R4are each independently selected from at least one of methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, iso-butyl, and tert-butyl;

[0053] Further preferably, the molecular sieve in the composite catalytic material is MFI-type molecular sieve, the template agent is tetrapropylammonium hydroxide or a mixture of tetrapropylammonium hydroxide and one or more selected from tetrapropylammonium chloride and tetrapropylammonium bromide; or

[0054] the molecular sieve in the composite catalytic material is MEL-type molecular sieve, the template agent is tetrabutylammonium hydroxide or a mixture of tetrabutylammonium hydroxide and one or more selected from tetrabutylammonium chloride and tetrabutylammonium bromide; or

[0055] the molecular sieve in the composite catalytic material is Beta-type molecular sieve, the template agent is tetraethylammonium hydroxide or a mixture of tetraethylammonium hydroxide and one or more selected from tetraethylammonium chloride and tetraethylammonium bromide.

[0056] Optionally, in step a, the silicon source is an organosilicon ester, and the mixture of the template agent, the organosilicon ester, the backbone heteroatom precursor, and water further comprises a hydrolysis alcohol-removing treatment to obtain the hydrolysis solution;

[0057] Optionally, the conditions of the hydrolysis alcohol-removing treatment comprise stirring the hydrolysis at 0-95°C for 2-10 hours; preferably stirring the hydrolysis at 50-95°C for 2-8 hours.

[0058] Optionally, in step S1, the framework heteroatom precursor comprises at least one of an organic framework heteroatom precursor and an inorganic framework heteroatom precursor; the inorganic framework heteroatom precursor is at least one selected from chlorides, nitrates and sulfates of the heteroatom element Q; the inorganic framework heteroatom precursor is an organic acid ester containing the heteroatom element Q, and is at least one selected from structures of the following formula (C):

[0059]

[0060] wherein R5, R6, R7and R8are each selected from alkyl groups having 1-6 carbon atoms, preferably linear alkyl groups having 1-4 carbon atoms and branched alkyl groups having 3-6 carbon atoms, further preferably R5, R6, R7and R8are each selected from linear alkyl groups having 2-4 carbon atoms and branched alkyl groups having 2-4 carbon atoms;

[0061] 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 selected from one of ethyl, n-propyl, i-propyl, n-butyl, sec-butyl, i-butyl or t-butyl;

[0062] Preferably, the framework heteroatom is titanium, and the framework heteroatom precursor is selected from one or more of titanium tetrachloride, titanium sulfate, titanium nitrate, tetraethyl titanate, tetrapropyl titanate and tetrabutyl titanate; the framework heteroatom is boron, and the framework heteroatom precursor is selected from one or more of boric acid and boric acid salts; the framework heteroatom is tin, and the framework heteroatom precursor is selected from one or more of tin halides, stannous halides, stannous sulfate, stannic sulfate, stannate salts, stannous salts, stannic nitrate, stannic oxide and stannous oxide; the framework heteroatom is aluminum, and the framework heteroatom precursor is selected from one or more of sodium aluminate, aluminum sulfate, boehmite, metallic aluminum, aluminum nitrate, aluminum isopropoxide and aluminum hydroxide; the framework heteroatom is phosphorus, and the framework heteroatom precursor is selected from one or more of orthophosphoric acid, triethyl phosphonic acid and metaphosphoric acid salts; the framework heteroatom is germanium, and the framework heteroatom precursor is selected from one or more of germanium oxide, germanium alkoxide, germanium chloride and sodium germanate.

[0063] 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 the metal element M; the water-soluble inorganic salt of the metal element M is selected from one or more of chlorides, hydrated chlorides, sulfates, hydrated sulfates and nitrates of the metal element M; the organic metal compound is an organic ligand compound of the metal element M; preferably the metal M precursor is a water-soluble inorganic salt of the metal element M;

[0064] Optionally, the metal element M is selected from one or more of manganese, iron, cobalt, nickel, palladium, platinum, copper and gold;

[0065] Preferably, the metal M precursor is in the form of an aqueous solution of the metal M precursor, the aqueous solution of the metal M precursor having a molar ratio of the metal element M to water of 1:(50-500).

[0066] Optionally, in step S1, the nitrogen-containing ligand is an alkyl amine compound containing only amino groups or an amine compound containing other coordinating groups, the other coordinating groups including one or more of hydroxyl groups, carboxyl groups, carbonyl groups and mercapto groups.

[0067] Preferably, the nitrogen-containing ligand is one or more of an alkyl amine compound containing only amino groups having the structure shown in the following formula (D), an alcohol amine compound having the structure shown in the following formula (E) and an aminocarboxylic acid compound having the structure shown in the following formula (F):

[0068] R9(NH2) n Formula (D);

[0069] wherein n is 1 or 2; when n is 1, R9is an alkyl group having 1-6 carbon atoms, preferably a straight-chain alkyl group having 1-6 carbon atoms and a branched-chain alkyl group having 3-6 carbon atoms, and further preferably one of a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, a sec-butyl group, an iso-butyl group, a tert-butyl group, an n-pentyl group, a neopentyl group, an iso-pentyl group, a tert-pentyl group and an n-hexyl group; and when n is 2, R9is an alkylene group having 1-6 carbon atoms, preferably a straight-chain alkylene group having 1-6 carbon atoms and a branched-chain alkylene group having 3-6 carbon atoms, and further preferably one of a methylene group, an ethylene group, an n-propylene group, an n-butylene group, an n-pentylene group and an n-hexylene group;

[0070] (HOR 10 ) m NH (3m) Formula (E);

[0071] wherein R 10 is an alkylene group having 1-4 carbon atoms and a branched-chain alkylene group having 3-4 carbon atoms, and preferably one of a methylene group, an ethylene group, an n-propylene group and an n-butylene group; and m is 1, 2 or 3, and when m is greater than 1, the plurality of R 10 are the same or different;

[0072] (HOOCR 11 ) x NH (3x) Formula (F);

[0073] wherein R 11alkylene having 1 to 4 carbon atoms and branched alkylene having 3 to 4 carbon atoms, preferably one of methylene, ethylene, n-propylene and n-butylene; x is 1, 2 or 3, when x is greater than 1, the multiple R 11 identical or different;

[0074] Further preferably, the nitrogen-containing ligand is selected from one or more of ethylamine, ethylenediamine, ethanolamine and ethylenediaminetetraacetic acid.

[0075] Optionally, in step S1, the silanization agent has a general formula of R 12 Si(R 13 )(R 14 )R 15 wherein R 12 , R 13 , R 14 , R 15 are each independently halogen, alkyl, alkoxy, aromatic group, thiol or amine group, and at least one of R 12 , R 13 , R 14 , R 15 is alkyl, alkoxy, aromatic group, thiol or amine group; the number of carbon atoms of the alkyl, alkoxy, thiol and amine group is each independently 1 to 18, and the number of carbon atoms of the aromatic group is 6 to 18;

[0076] 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 and 3-mercaptopropyltrimethoxysilane; further preferably, at least one of N-phenyl-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane and 3-mercaptopropyltrimethoxysilane.

[0077] Optionally, in step S2, the hydrothermal crystallization treatment is performed under autogenous pressure, 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.

[0078] Optionally, the conditions of the calcination treatment include: a calcination temperature of 400-900℃, and a calcination time of 1-16 hours; preferably, the calcination temperature is 400-800℃, and the calcination time is 2-8 hours. Through the above technical solution, the present disclosure provides a heterogeneous oxidation reaction method for preparing carboxylic acid by oxygen oxidation of alcohol, which adopts a metal-containing hierarchical pore molecular sieve composite catalytic material as a catalyst. The molecular sieve of the composite catalytic material has a large specific surface area, pore volume and macromolecular substrate reactivity, and the metal nanoparticles have a high dispersion degree in the molecular sieve. In the alcohol-oxygen oxidation reaction, high conversion of alcohol and high selectivity of carboxylic acid can be obtained under relatively mild conditions.

[0079] Other features and advantages of the present disclosure will be described in detail in the following detailed description section. BRIEF DESCRIPTION OF DRAWINGS

[0080] 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 detailed description to explain the present disclosure, but do not constitute a limitation of the present disclosure. In the drawings:

[0081] Figure 1 Co XPS spectrum of the product prepared in Preparation Example 1.

[0082] Figure 2 Ti XPS spectrum of the product prepared in Preparation Example 1.

[0083] Figure 3 SEM spectrum of the product prepared in Preparation Example 1.

[0084] Figure 4 XRD spectrum of the product prepared in Preparation Example 1. DETAILED DESCRIPTION

[0085] The detailed description of the specific embodiments of the present disclosure is described below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure, and are not intended to limit the present disclosure.

[0086] The first aspect of the present disclosure provides a method for preparing carboxylic acid by oxygen oxidation of alcohol, which comprises the following steps:

[0087] contacting an alcohol compound and an olefin compound with a catalyst in the presence of oxygen to perform an oxidation reaction;

[0088] The catalyst is a composite catalytic material, which comprises a framework heteroatom molecular sieve and a metal element M dispersed in the intracrystalline of the molecular sieve; the framework heteroatom molecular sieve is a molecular sieve in which at least part of the silicon in the full-silicon molecular sieve framework is replaced by a heteroatom element Q, and the heteroatom element Q is one or more selected from titanium, boron, zirconium, tin, aluminum, phosphorus and germanium.

[0089] The inventors of the present disclosure surprisingly found that, when metal-containing nanoparticles are combined with a framework heteroatom molecular sieve composite catalytic material as a catalyst, the oxidation reaction of an alcohol compound under the action of the catalyst can effectively improve the oxidation reaction rate, shorten the reaction time, and achieve high conversion of alcohol and high selectivity of carboxylic acid under relatively mild conditions.

[0090] The inventors of the present disclosure surprisingly found that, when a heteroatom precursor, a metal M precursor, a nitrogen-containing ligand and a silanization reagent (containing at least one coordination group complexed with the metal element M) are introduced into the reaction raw materials for synthesizing the molecular sieve by crystallization, and then subjected to hydrothermal crystallization treatment and calcination treatment, the heteroatom can be introduced into the molecular sieve framework, and the framework heteroatom molecular sieve of the composite catalytic material has a multi-level pore structure (micropore and mesopore) and a large specific surface area and pore volume, the metal oxide nanoparticle size is uniform and can be uniformly dispersed in the pore channel of the framework heteroatom molecular sieve, and a certain amount of metal M nanoparticles also exist on the surface of the pore channel; the heteroatom metal site on the molecular sieve framework and the metal element M metal site (nanoparticle) in the pore channel can also have a synergistic catalytic effect, further improving the catalytic activity in the co-oxidation reaction of macromolecular aldehyde / olefin; the inventors further found that, compared with the XPS binding energy of the metal M element in the stable oxide aggregate, the XPS binding energy of the metal M element introduced in the composite catalytic material of the present disclosure has changed, and the heteroatom in the framework can also affect the XPS binding energy of the metal M element in the composite catalytic material; when the change of the XPS chemical binding energy of the metal element M in the composite catalytic material compared with the XPS chemical binding energy of the metal element M in the stable oxide is within a certain range, the composite catalytic material can obtain higher alcohol conversion rate and carboxylic acid selectivity.

[0091] In one embodiment, the alcohol compound is selected from one or more of alkyl alcohol with carbon atom number of 6-12 and aryl alcohol with carbon atom number of 7-14;

[0092] Preferably, the alcohol compound is selected from one or more of sec-butyl alcohol, cyclohexanol, hexanol, 2-methyl-1-butanol, 1-methylcyclopentanol, 2-hexyl-1-octanol, benzyl alcohol, 1-pentanol, n-octanol, 2-hexyl-1-octanol and 1-butanol;

[0093] The olefin compound is selected from one or more of aliphatic olefins with carbon atom number of 6-20.

[0094] Preferably, the method further comprises: after mixing the alcohol with the olefin compound, the alcohol is contacted with the catalyst to perform the oxidation reaction; and the molar ratio of the alcohol reactant to the olefin reactant is 1:(0.5-5), preferably 1:(0.5-3).

[0095] In one embodiment, the oxidation reaction is performed under the following conditions: the reaction temperature is 40-100°C, preferably 60-80°C; the reaction time is 1-48h, preferably 2-24h; and the oxygen pressure is 0.1-0.5MPa, preferably 0.1-0.3MPa.

[0096] The weight ratio of the catalyst to the alcohol compound is 1:(0.5-20), preferably 1:(0.5-10).

[0097] Preferably, the reactor for the oxidation reaction is any one of a tank reactor, a fixed bed reactor, a moving bed reactor, a suspended bed reactor and a slurry bed reactor.

[0098] In one preferred embodiment, the metal element M is a metal element capable of forming a stable oxide aggregate.

[0099] The composite catalytic material has the following XPS characteristics:

[0100] The electron binding energy of the metal element M in the composite catalytic material is denoted as T1.

[0101] The electron binding energy of the metal element M in the stable oxide aggregate is denoted as T2, and T0 defined by the following formula (1) is any value between 0.6-1.5eV.

[0102] T0=T1-T2 Formula (1)

[0103] The present disclosure provides a metal oxide nanoparticle and molecular sieve composite catalytic material, the molecular sieve of the composite catalytic material has a hierarchical pore structure and a large specific surface area, pore volume and macromolecular substrate reactivity; and the metal oxide nanoparticles are uniformly dispersed in the mesoporous channels of the hierarchical pore heteroatom framework molecular sieve. There is a significant interaction between the metal elements of the metal oxide particles and the heteroatoms in the framework, and after introducing heteroatoms into the molecular sieve framework, the two metal sites in the composite catalytic material can have a synergistic catalytic effect, effectively improving the catalytic activity of the composite catalytic material for macromolecular substrates.

[0104] In a preferred embodiment, T0 is any value between 0.80 and 1.5 eV. When T0 of the composite catalytic material is in this range, the composite catalytic material has higher catalytic activity.

[0105] In an embodiment, the framework heteroatomic molecular sieve in the composite catalytic material is one or more of MFI structure molecular sieve (such as S-1), MEL structure molecular sieve (such as S-2), BEA structure molecular sieve (such as Beta), MWW structure molecular sieve (such as MCM-22), two-dimensional hexagonal structure molecular sieve (such as MCM-41, SBA-15), MOR structure molecular sieve (such as MOR), TUN structure molecular sieve (such as TUN), and other structure silicon molecular sieve (such as ZSM-48, MCM-48); preferably 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, such as one of S-1, S-2, and Beta; further preferably MFI structure molecular sieve, such as S-1.

[0106] In an embodiment, the metal element M is selected from one or more of manganese, iron, cobalt, nickel, palladium, platinum, copper, and gold.

[0107] The stable oxide aggregate in the present disclosure refers to an oxide aggregate in which the metal element M known in the art can exist most stably in a natural state;

[0108] In an alternative embodiment, when the metal M is Co, the stable oxide aggregate is Co3O4 aggregate;

[0109] In an alternative embodiment, when the metal M is Mn, the stable oxide aggregate is MnO2 aggregate;

[0110] In an alternative embodiment, when the metal M is Fe, the stable oxide aggregate is Fe2O3 aggregate;

[0111] In an alternative embodiment, when the metal M is Ni, the stable oxide aggregate is NiO aggregate;

[0112] In an alternative embodiment, when the metal M is Pd, the stable oxide aggregate is PdO aggregate;

[0113] In an alternative embodiment, when the metal M is Pt, the stable oxide aggregate is PtO2 aggregate;

[0114] In an alternative embodiment, when the metal M is Cu, the stable oxide aggregates are CuO aggregates;

[0115] wherein when the metal element M is Co, Mn, Fe, Ni or Cu, the electron binding energy of the metal element M is 2p 3 / 2 of the metal element M; when the metal element M is Au or Pt, the electron binding energy of the metal element M is 4f 7 / 2 of the metal element M; when the metal element M is Pd, the electron binding energy of the metal element M is 3d 5 / 2 of the metal element M.

[0116] In an embodiment, the molar ratio of the framework heteroatom element to the silicon element in the composite catalytic material is (0.002-0.05):1, preferably (0.003-0.045):1.

[0117] The molar ratio of the metal M element to the silicon element is (0.001-0.25):1, preferably (0.002-0.15):1.

[0118] In an 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, 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 0.5-5.5 nm. The composite catalytic material in the present disclosure has a hierarchical pore structure, which is beneficial for catalyzing reactions of reaction substrates of different sizes, especially catalyzing reactions of macromolecular substrates.

[0119] In an embodiment, the catalyst is prepared by a preparation method comprising the following steps:

[0120] S1, mixing a template agent, a silicon source, a framework heteroatom precursor, water, a metal M precursor, a nitrogen-containing ligand and a silylation reagent to obtain a reaction mixture;

[0121] S2, performing hydrothermal crystallization treatment on the reaction mixture to obtain a crystallization product, and performing calcination treatment on the crystallization product;

[0122] wherein the framework heteroatom precursor contains a heteroatom element Q selected from one of titanium, boron, zirconium, tin, aluminum, phosphorus and germanium; and the silylation reagent contains at least one coordination group complexed with the metal element M.

[0123] The present disclosure introduces a heteroatom precursor into a reaction mixture for synthesizing a molecular sieve, and the heteroatom mainly enters the molecular sieve framework during crystallization. The present disclosure also introduces a metal element precursor, a nitrogen-containing ligand and a silylating agent into the reaction mixture, wherein the nitrogen-containing ligand can be complexed with metal M ions to fix and disperse the metal element; and the coordination group of the silylating agent can be complexed with the metal to fix and disperse the metal element, and the space layering effect of the alkyl chain can expand the pore. Thus, a framework heteroatom molecular sieve with a hierarchical pore structure is finally prepared, and metal M oxide nanoparticles can also be uniformly dispersed in the mesoporous channels of the hierarchical pore framework heteroatom molecular sieve.

[0124] The present inventors surprisingly found in experiments that, compared with before calcination, the XPS spectrum of the composite catalytic material obtained after hydrothermal crystallization and calcination has a significantly increased electron binding energy of the metal element M, and the metal nanoparticles in the composite obtained after calcination interact with the framework heteroatom. The present inventors made in-depth research on the change of the electron binding energy of the metal element M in the composite catalytic material before and after calcination, and found that T0'(T0' = T3-T4; T3 is the electron binding energy of the metal element M in the product of the calcination treatment of the crystallization product, and T4 is the electron binding energy of the metal element M in the crystallization product) is associated with the catalytic activity of the composite catalytic material, that is, the interaction between the metal element M and the framework heteroatom Q in the composite catalytic material can further affect the catalytic activity of the composite catalytic material, and when T0' is any value between 0.4 and 0.8 eV, the composite catalytic material can obtain higher catalytic activity.

[0125] In a preferred embodiment, the electron binding energy of the metal element M in the product of the calcination treatment of the crystallization product is denoted as T3;

[0126] The electron binding energy of the metal element M in the crystallization product is denoted as T4;

[0127] The calcination treatment makes T0' defined by formula (2) as any value between 0.4 and 0.8 eV;

[0128] T0' = T3-T4 formula (2).

[0129] In one embodiment, in step S1, the molar ratio of the silicon source: the template agent: the framework heteroatom precursor: water: the metal element M: the silylating agent in step S1 is 1: (0.001-1): (0.002-0.05): (5-100): (0.001-0.25): (0.015-0.4); preferably 1: (0.001-1): (0.003-0.045): (5-100): (0.002-0.15): (0.025-0.3) in terms of SiO2.

[0130] Preferably, the molar ratio of the nitrogen-containing ligand to the metal element M is (0.5-5): 1.

[0131] Specifically, the water used in step S1 can be the water commonly used in the synthesis of molecular sieves, and preferably is deionized water in order to avoid the introduction of heteroatoms.

[0132] In one preferred embodiment, step S1 comprises the following steps:

[0133] a. mixing the template agent, the silicon source, the framework heteroatom precursor and the water to obtain a hydrolysis solution of silicon;

[0134] b. adding the nitrogen-containing ligand to the aqueous solution of the metal M precursor to obtain a first mixture; mixing the first mixture with the hydrolysis solution of silicon to obtain a second mixture;

[0135] c. adding the silylating agent to the second mixture, and mixing to obtain the reaction mixture;

[0136] Preferably, the mixing in step c. comprises stirring at 20-80°C for 0.5-2 hours.

[0137] In one embodiment, the silicon source is selected from at least one of organosilicon grease, solid silica gel, white carbon black and silica sol; preferably is selected from at least one of organosilicon grease, solid silica gel and white carbon black;

[0138] Further preferably, the organosilicon grease has the structure shown in the following formula (A):

[0139]

[0140] 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 deach independently selected from a linear 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 each independently selected from a linear alkyl group having 1 to 4 carbon atoms or a branched alkyl group having 3 to 4 carbon atoms; further preferably, the R

[0141] In a preferred embodiment, the organosilicon grease is selected from one or more of tetramethyl silicate, tetraethyl silicate, tetrabutyl silicate and dimethyl diethyl silicate.

[0142] According to the present disclosure, in step S1, the template agent is an organic base, preferably at least one selected from quaternary ammonium base, aliphatic amine and aliphatic alcohol amine. Among them, the quaternary ammonium base can be an organic quaternary ammonium base; the aliphatic amine can be a compound formed by replacing at least one hydrogen in NH3 with an aliphatic hydrocarbon group (such as an alkyl group); the aliphatic alcohol amine can be a compound formed by replacing at least one hydrogen in various NH3 with an aliphatic group containing a hydroxyl group (such as an alkyl group).

[0143] In a further preferred embodiment, the template agent is at least one selected from quaternary ammonium bases having a structure represented by the following formula (B):

[0144] wherein R1, R2, R3 and R4 are each selected from an alkyl group having 1 to 4 carbon atoms, preferably a linear alkyl group having 1 to 4 carbon atoms and a branched alkyl group having 3 to 4 carbon atoms, more preferably R1, R2, R3 and R4 are each selected from at least one 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.

[0145] In a preferred embodiment, the molecular sieve in the composite catalytic material is an MFI type molecular sieve, the template agent is tetrapropylammonium hydroxide or a mixture of tetrapropylammonium hydroxide and one or more selected from tetrapropylammonium chloride, tetrapropylammonium bromide; or

[0146] In another preferred embodiment, the molecular sieve in the composite catalytic material is an MEL type molecular sieve, the template agent is tetrabutylammonium hydroxide or a mixture of tetrabutylammonium hydroxide and one or more selected from tetrabutylammonium chloride, tetrabutylammonium bromide; or

[0147] In another preferred embodiment, the molecular sieve in the composite catalytic material is a Beta type molecular sieve, the template agent is tetraethylammonium hydroxide or a mixture of tetraethylammonium hydroxide and one or more selected from tetraethylammonium chloride, tetraethylammonium bromide.

[0148] In one embodiment, in step a, the silicon source is an organosilicon grease, and the hydrolysis alcohol-removing treatment is further included after mixing the template agent, the organosilicon grease, the skeleton heteroatom precursor and water, to obtain the hydrolysis solution.

[0149] The conditions of the hydrolysis alcohol-removing 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; wherein the mass content of the alcohol produced by the hydrolysis of the organosilicon source in the hydrolysis solution is 10 ppm or less.

[0150] According to the present disclosure, the optional range of the type of metal precursor is wide, and any substance containing the metal element (for example, a compound containing a metal element and / or a metal element) can achieve the purpose of the present disclosure.

[0151] In one embodiment, in step S1, the skeleton heteroatom precursor includes at least one of an organic skeleton heteroatom precursor and an inorganic skeleton heteroatom precursor; the inorganic skeleton heteroatom precursor is at least one selected from chlorides, nitrates or sulfates of heteroatom elements; the inorganic skeleton heteroatom precursor is an organic acid ester containing a heteroatom element, and is at least one selected from structures represented by the following formula (C):

[0152]

[0153] wherein R5, R6, R7and R8are each selected from alkyl groups having 1-6 carbon atoms, preferably linear alkyl groups having 1-4 carbon atoms and branched alkyl groups having 3-6 carbon atoms, and further preferably R5, R6, R7and R8are each selected from linear alkyl groups having 2-4 carbon atoms and branched alkyl groups having 2-4 carbon atoms;

[0154] Alternatively, R5, R6, R7and R8are each selected from one of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, isoamyl, hexyl or isohexyl; preferably each independently selected from one of ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl or tert-butyl;

[0155] In one optional embodiment, the skeleton heteroatom is titanium, and the skeleton heteroatom precursor is selected from one or more of titanium tetrachloride, titanium sulfate, titanium nitrate, tetraethyl titanate, tetrapropyl titanate and tetrabutyl titanate;

[0156] In one optional embodiment, the skeleton heteroatom is boron, and the skeleton heteroatom precursor is selected from one or more of boric acid and boric acid salts;

[0157] In an alternative embodiment, the skeletal heteroatom is tin, and the skeletal heteroatom precursor is selected from one or more of tin halide, stannous halide, stannous sulfate, tin sulfate, stannate, stannite, tin nitrate, tin oxide, and stannous oxide;

[0158] In an alternative embodiment, the skeletal heteroatom is aluminum, and the skeletal heteroatom precursor is selected from one or more of sodium metaaluminate, aluminum sulfate, boehmite, metallic aluminum, aluminum nitrate, aluminum isopropoxide, and aluminum hydroxide;

[0159] In an alternative embodiment, the skeletal heteroatom is phosphorus, and the skeletal heteroatom precursor is selected from one or more of orthophosphoric acid, triethylphosphonic acid, and metaphosphate;

[0160] In an alternative embodiment, the skeletal heteroatom is germanium, and the skeletal heteroatom precursor is selected from one or more of germanium oxide, germanium alkoxide, germanium chloride, and sodium germanate.

[0161] In one embodiment, 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 the metal element M; the water-soluble inorganic salt of the metal element M is selected from one or more of a chloride, a hydrated chloride, a sulfate, a hydrated sulfate, and a nitrate of the metal element M; the organic metal compound is an organic ligand compound of the metal element M; preferably the metal M precursor is a water-soluble inorganic salt of the metal element M.

[0162] The metal element M is selected from one or more of manganese, iron, cobalt, nickel, palladium, platinum, copper, and gold.

[0163] Preferably, the metal M precursor is in the form of an aqueous solution of the metal M precursor, and the molar ratio of the metal element M to water in the aqueous solution of the metal M precursor is 1 : (50-500).

[0164] In one embodiment, in step S1, the nitrogen-containing ligand is an alkyl amine compound containing only amino groups or an amine compound containing other coordination groups, including one or more of a hydroxyl group, a carboxyl group, a carbonyl group, and a mercapto group. In the present disclosure, the “alkyl amine compound containing only amino groups” means that the alkyl amine compound contains only one kind of nitrogen-containing group, i.e., amino groups, and does not contain other kinds of nitrogen-containing groups, but the number of amino groups contained can be one or more.

[0165] In a preferred embodiment, the nitrogen-containing ligand is one or more of an alkyl amine compound containing only amino groups having the structure shown in the following formula (D), an alcohol amine compound having the structure shown in the following formula (E), and an aminocarboxylic acid compound having the structure shown in the following formula (F):

[0166] R9(NH2) n Formula (D);

[0167] wherein n is 1 or 2; when n is 1, R9is an alkyl group having 1 to 6 carbon atoms, preferably a linear alkyl group having 1 to 6 carbon atoms and a branched alkyl group having 3 to 6 carbon atoms, further preferably one of a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, a sec-butyl group, an iso-butyl group, a tert-butyl group, an n-pentyl group, a neopentyl group, an iso-pentyl group, a tert-pentyl group and an n-hexyl group; when n is 2, R9is an alkylene group having 1 to 6 carbon atoms, preferably a linear alkylene group having 1 to 6 carbon atoms and a branched alkylene group having 3 to 6 carbon atoms, further preferably one of a methylene group, an ethylene group, an n-propylene group, an n-butylene group, an n-pentylene group and an n-hexylene group;

[0168] (HOR 10 ) m NH (3m) Formula (E);

[0169] wherein R 10 is an alkylene group having 1 to 4 carbon atoms and a branched alkylene group having 3 to 4 carbon atoms, preferably one of a methylene group, an ethylene group, an n-propylene group and an n-butylene group; m is 1, 2 or 3, and when m is greater than 1, the plurality of R 10 are the same or different;

[0170] (HOOCR 11 ) x NH (3x) Formula (F);

[0171] wherein R 11 is an alkylene group having 1 to 4 carbon atoms and a branched alkylene group having 3 to 4 carbon atoms, preferably one of a methylene group, an ethylene group, an n-propylene group and an n-butylene group; x is 1, 2 or 3, and when x is greater than 1, the plurality of R 11 are the same or different.

[0172] In further preferred embodiments, the nitrogen-containing ligand is selected from one or more of ethylamine, ethylenediamine, ethanolamine and ethylenediaminetetraacetic acid.

[0173] In one embodiment, in step S1, the silanization reagent has the general formula R 12 Si(R 13 )(R 14 )R 15 wherein R 12 , R 13 , R 14 , R 15 are each independently a halogen, an alkyl group, an alkoxy group, an aromatic group, a thiol group or an amine group, and R 12 , R 13R 14 R 15 At least one of them is an alkyl, alkoxy, aromatic, mercapto, or amino group; the number of carbon atoms of each of the alkyl, alkoxy, mercapto, and amino groups is 1 to 18, preferably 1 to 12; the number of carbon atoms of the aromatic group can be 6 to 18, preferably 6 to 12.

[0174] Preferably, the silanizing 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; more preferably, at least one of N-phenyl-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, and 3-mercaptopropyltrimethoxysilane.

[0175] In this disclosure, different silanizing agents can be selected for different metal elements M. For example, when the metal element M is Co, the silanizing agent is at least one of N-phenyl-3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, and N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane; when the metal element M is Au or Pt, the silanizing agent is at least one of 3-mercaptopropyltrimethoxysilane and 3-mercaptopropyltriethoxysilane.

[0176] In one embodiment, in step S2, the conditions for the hydrothermal crystallization treatment include: being carried out under autogenous pressure, with a hydrothermal crystallization time of 0.5 to 10 days and a hydrothermal crystallization temperature of 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.

[0177] In one embodiment, in step S2, the conditions for the calcination treatment include: a calcination temperature of 400–900°C and a calcination time of 1–16 hours; preferably, the calcination temperature is 400–800°C and the calcination time is 2–8 hours.

[0178] The present disclosure is further described in detail below through examples.

[0179] In this disclosure, the sample was characterized by XPS on an ESCALAB 250 X-ray photoelectron spectrometer with monochromatic Al Kα X-rays, energy 1486.6 eV, power 150 W, and nuclear shift was corrected using the C1s peak (284.8 eV) of contaminated carbon.

[0180] X-ray diffraction (XRD) phase pattern measurement of the sample was performed on a Siemens D5005 X-ray diffractometer with a Kα (Cu) radiation source and a test range 2θ of 0.5-70°.

[0181] Scanning electron microscope (SEM) images of the sample were obtained on a Hitachi S4800 high resolution cold field emission scanning electron microscope.

[0182] Transmission electron microscope (TEM) images of the sample were obtained on a FEI Tecnai G2 F20 S-TWIN transmission electron microscope. The average particle size of the metal oxide nanoparticles was obtained according to the TEM electron microscope test.

[0183] Total specific surface area and total pore volume of the sample were measured 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 measured by low temperature nitrogen adsorption according to the standard method of ASTM D4222-98.

[0184] Preparation Example 1

[0185] (1) 1.63 g of a 25.05 wt% tetrapropylammonium hydroxide (TPAOH, 0.002 mol) aqueous solution, 20.8 g of tetraethyl silicate (0.1 mol), 0.170 g of tetrabutyl titanate (0.0005 mol), and 9 g of water (0.5 mol) were sequentially added to a 500 mL beaker, placed on a magnetic stirrer with heating and stirring functions, mixed uniformly, and stirred at 80°C for 4 hours, with the evaporation of water being replenished in a timely manner, to obtain a colorless transparent silica gel solution;

[0186] (2) 0.3 g of cobalt nitrate hexahydrate (0.001 mol) and 1.8 g (0.1 mol) of water were stirred uniformly, and then 0.0005 mol of ethylenediamine was added, and the cobalt aqueous solution was mixed with the hydrolysis solution of silica obtained in step (1);

[0187] (3) 0.64 g of N-phenyl-3-aminopropyltrimethoxysilane (PHAPTMS) was added to the mixture of step (2) and stirred for 0.5 hours;

[0188] (4) The mixture obtained in step (3) was transferred to a stainless steel sealed autoclave, and crystallized at 170°C for 28 hours to obtain a sample, which was filtered, washed, dried at 120°C for 6 hours, and then calcined in a muffle furnace at 550°C for 6 hours to prepare a composite catalytic material product, which was denoted as CAT-1.

[0189] The BET surface area, total pore volume, micropore volume, mesopore volume of CAT-1 and the average particle size of the metal nanoparticles contained in the composite material are listed in Table 2. The Co XPS spectrum of CAT-1 is shown in Figure 1 The Ti XPS spectrum of CAT-1 is shown in Figure 2 Figure 2 There is a peak of framework Ti at 459.97 ev position, which proves that Ti heteroatom is successfully introduced into the framework in the obtained product. The SEM image of sample CAT-1 is shown in Figure 3 The XRD spectrum of sample CAT-1 is shown in Figure 4 The XRD analysis shows that it has MFI structure.

[0190] Preparation of Comparative Example 1

[0191] Preparation of Comparative Example 1

[0192] Preparation of Comparative Example 2

[0193] 0.03 g of cobalt nitrate hexahydrate and 0.18 g of water were stirred to obtain an aqueous solution of cobalt, then 10.2 g of alumina support (Innochem product number A17263) was added, stirred for 4 h, the solvent was evaporated, 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, and the obtained product was recorded as DCAT-2.

[0194] Preparation of Comparative Example 3

[0195] 0.03 g of cobalt nitrate hexahydrate and 0.18 g of water were stirred to obtain an aqueous solution of cobalt, then 10.2 g of alumina support (Innochem product number A17263) was added, stirred for 4 h, the solvent was evaporated, 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, and the obtained product was recorded as DCAT-2.

[0196] Preparation of Comparative Example 3

[0197] The corresponding products were prepared according to the method of Preparation Example 1, and the obtained products were recorded as CAT-2 to CAT-9, and the ratio and synthesis conditions, results are shown in Table 1, and other conditions and operations refer to Preparation Example 1. The SEM images thereof are similar to Figure 3 The XRD analysis thereof has MFI structure, and the XRD spectrum is similar to Figure 4 The XRD analysis thereof has MFI structure, and the XRD spectrum is similar to

[0198] Preparation of Comparative Example 3

[0199] ​A cobalt-containing hierarchical pore β molecular sieve was prepared according to the method of Reference Example 1, with the ratio changed and the template changed to tetraethylammonium hydroxide (TEAOH). The product is denoted as CAT-10, and the ratio, synthesis conditions and results are shown in Table 1.

[0200] Preparation Example 11

[0201] A cobalt-containing hierarchical pore MEL molecular sieve was prepared in this example, and the product is denoted as CAT-11. The method of Reference Example 1 was used, with the ratio changed and the template changed to tetrabutylammonium hydroxide (TBAOH). The product is denoted as CAT-10, and the ratio, synthesis conditions and results are shown in Table 1.

[0202] Preparation Example 12

[0203] The corresponding product was prepared according to the method of Preparation Example 1, and the ratio, synthesis conditions and results are shown in Table 1. The other conditions and operations were according to Reference Example 1, and the product obtained is denoted as CAT-12. The hydrothermal crystallization temperature was 120°C, the time was 8 days, the calcination temperature was 850°C, and the calcination time was 10 hours.

[0204] The BET specific surface area, total pore volume, micropore volume and mesopore volume of the products obtained in the above preparation examples and comparative examples, and the average particle size of the metal nanoparticles contained in the composite catalytic material are shown in Table 2 below.

[0205] Table 1

[0206]

[0207]

[0208] In Table 1, the cobalt nitrate is cobalt nitrate hexahydrate; 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 (diamino functional silane, N-aminoethyl-γ-aminopropyltrimethoxysilane). The reagents used in the present disclosure can be obtained through conventional purchase channels.

[0209] Table 2

[0210]

[0211] The pores with a diameter less than 2 nm are micropores, and the pores with a diameter between 2 nm and 50 nm are mesopores.

[0212] According to Table 2, compared with Comparative Example 1 (without adding a silanization reagent), the products obtained by adding a silanization reagent in the preparation process of Examples 1-12 have a higher mesopore volume, indicating that the method provided by the present disclosure can effectively expand the pore of the molecular sieve.

[0213] In addition, compared with DCAT-1-DCAT-3, the composite catalytic material CAT-1-CAT-12 provided by the present disclosure can simultaneously have a large mesopore volume, a large specific surface area, and a smaller metal nanoparticle particle size, indicating that the metal nanoparticles in the composite catalytic material obtained by the present disclosure have a lower aggregation degree and a higher dispersion degree.

[0214] Reaction Example 1

[0215] The effect of the composite catalytic material provided by the present disclosure in alcohol oxidation reaction is illustrated.

[0216] The samples prepared in the above preparation examples and comparative examples were used to catalyze alcohol oxidation. 1 mmol of an alcohol compound (the specific type of the alcohol compound is listed in Table 3) and 1 mmol of 1-octene were mixed with 2.5 mL of acetonitrile solvent, and then contacted with 50 mg of the catalyst in a slurry bed reactor. The contact temperature was 80°C, the oxygen pressure was 0.1 MPa, and the time was 24 h. The results are shown in Table 3 below.

[0217] Among them, the product distribution was determined by using an Agilent 6890N chromatograph and an HP-5 capillary column (30 m x 0.25 mm).

[0218] Alcohol conversion rate (%) = moles of alcohol participating in the reaction / moles of alcohol added x 100%;

[0219] Olefin conversion rate (%) = moles of olefin participating in the reaction / moles of olefin added x 100%;

[0220] Carboxylic acid selectivity (%) = moles of carboxylic acid / moles of alcohol participating in the reaction x 100%;

[0221] Among them, the moles of alcohol participating in the reaction = moles of alcohol fed - moles of alcohol remaining in the obtained reaction mixture.

[0222] Table 3

[0223]

[0224]

[0225] As can be seen from Table 3, compared with Comparative Examples 1-3, the metal oxide nanoparticles and molecular sieve composite catalytic material prepared in Examples 1-12 of the present disclosure has a T0 in the range of 0.6-1.5 eV, and the composite catalytic material has higher catalytic activity, and higher alcohol conversion rate and carboxylic acid selectivity when used for alcohol oxidation reaction.

[0226] Comparing Examples 1-11 with Example 12, the composite catalytic material prepared in Examples 1-11 has a T0 in the range of 0.8-1.5 eV, and the catalytic effect of Examples 1-11 is better, and the alcohol conversion rate and carboxylic acid selectivity are higher.

[0227] Further, in order to explore the influence of the framework heteroatom on the XPS binding energy of the metal element in the composite catalytic material, the present disclosure takes the catalyst CAT-1 containing cobalt element in the preparation example as an example, and compares the change T0' (T0' = T3-T4) of the XPS binding energy T3 of the metal element Co of the composite catalytic material after calcination with the XPS binding energy T4 of the metal element Co of the crystallization product before calcination, as shown in Table 4 below.

[0228] Table 4

[0229] Catalyst [T0’ / eV] CAT-1 0.51 DCAT-1 0.21 DCAT-2 0.03 DCAT-3 0.24

[0230] Compared with DCAT-1-DCAT-3 prepared in Comparative Examples 1-3, the T0' of CAT-1 provided by the preparation example 1 of the present disclosure is 0.4-0.8 eV, which has higher cyclooctene conversion rate, isobutyraldehyde conversion rate and cyclooctene oxide selectivity.

[0231] Reaction Examples 2-4

[0232] The method of using CAT-2 as a catalyst and using sec-butanol as an alcohol reactant (the specific substance of the olefin compound is shown in Table 5) for oxidation to acid, the catalyst dosage is 50 mg, and the reaction effect under different oxidation reaction conditions is tested, and the specific reaction conditions and reaction results are shown in Table 5 below.

[0233] Table 5

[0234]

[0235] According to Reaction Example 2, the method provided by the present disclosure is suitable for a variety of olefin compounds (such as 1-hexene in Reaction Example 2), and has a wide range of adaptation.

[0236] Comparing Reaction Example 3 with Reaction Example 4, it can be seen that the oxidation reaction effect is better, and the alcohol, olefin conversion rate and carboxylic acid selectivity are higher when the reaction temperature is in the range of 60-80℃ in Reaction Example 4.

[0237] The preferred embodiments of the present disclosure are described in detail above with reference to the drawings, but the present disclosure is not limited to the specific details in the above-described embodiments. 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.

[0238] In addition, it should be noted that each specific technical feature described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, various possible combinations are not described again in the present disclosure.

[0239] In addition, any combination of various different embodiments of the present disclosure can also be made, as long as it does not deviate from the idea of the present disclosure, and it should also be considered as disclosed by the present disclosure.

Claims

1. A method for preparing carboxylic acids by oxygen oxidation of alcohols, characterized in that, The method includes the following steps: In the presence of oxygen, alcohols and alkenes are brought into contact with a catalyst to undergo oxidation reactions. The alcohols are selected from one or more of sec-butanol, cyclohexanol, hexanol, 2-methyl-1-butanol, 1-methylcyclopentanol, benzyl alcohol, 1-pentanol, n-octanol, 2-hexyl-1-octanol, and 1-butanol; The olefin compound is 1-octene and / or 1-hexene; The catalyst is a composite catalytic material, which includes a framework heteroatom molecular sieve and a metal element M dispersed within the crystals of the molecular sieve; the framework heteroatom molecular sieve is a molecular sieve in which at least part of the silicon in the all-silicon molecular sieve framework is replaced by a heteroatom element Q, and the heteroatom element Q is selected from one or more of titanium, boron and tin. The metal element M is a metal element capable of forming stable oxide aggregates, specifically selected from one or more of manganese, iron, cobalt and copper; The catalyst is prepared by a method comprising the following steps: S1, a. Mix the template agent, silicon source, framework heteroatom precursor and water to obtain a silicon hydrolysis solution; b. Add a nitrogen-containing ligand to the aqueous solution of the metal M precursor to obtain a first mixture; mix the first mixture with the silicon hydrolysis solution to obtain a second mixture; c. Add a silanizing agent to the second mixture and mix to obtain a reaction mixture; S2. The reaction mixture is subjected to hydrothermal crystallization treatment to obtain a crystallized product, and the crystallized product is then subjected to calcination treatment. The silanizing agent contains at least one coordinating group that is complexed with the metal element M; The composite catalytic material exhibits the following XPS characteristics: The electron binding energy of the metal element M in the composite catalytic material is denoted as T1; The electron binding energy of the metal element M in the stable oxide aggregate is denoted as T2. T0 is defined by the following formula (1) as any value between 0.6 and 1.5 eV; T0 = ​​T1 - T2 (Equation 1) 2. The method according to claim 1, characterized in that, The method further includes: mixing the alcohol compound with the olefin compound and then contacting the mixture with the catalyst to carry out an oxidation reaction; the molar ratio of the alcohol compound to the olefin compound is 1:(0.5-5).

3. The method according to claim 2, characterized in that, The molar ratio of the alcohol to the olefin is 1:(0.5-3).

4. The method according to claim 1, characterized in that, The conditions for the oxidation reaction include: a reaction temperature of 40-100℃; a reaction time of 1-48 hours; and an oxygen pressure of 0.1-0.5 MPa. The weight ratio of the catalyst to the alcohol compound is 1:(0.5-20).

5. The method according to claim 4, characterized in that, The conditions for the oxidation reaction include: a reaction temperature of 60-80℃; a reaction time of 2-24h; and an oxygen pressure of 0.1-0.3MPa.

6. The method according to claim 4, characterized in that, The weight ratio of the catalyst to the alcohol compound is 1:(0.5-10).

7. The method according to claim 1, characterized in that, The reactor for the oxidation reaction can be any one of a batch reactor, a fixed-bed reactor, a moving-bed reactor, a suspended-bed reactor, and a slurry-bed reactor.

8. The method according to claim 1, characterized in that, The T0 is any value between 0.8 and 1.5 eV.

9. The method according to claim 1, characterized in that, The framework heteroatom 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.

10. The method according to claim 1, characterized in that, The skeletal heteroatom molecules are selected from one or more of the following molecular sieve structures: MFI, MEL, BEA, MCM, and SBA.

11. The method according to claim 10, characterized in that, The framework heteroatom molecular sieve is one or more of MFI structure molecular sieve, MEL structure molecular sieve and BEA structure molecular sieve.

12. The method according to claim 1, characterized in that, When the metal M is Co, the stable oxide aggregate is a Co3O4 aggregate; When the metal M is Mn, the stable oxide aggregate is a MnO2 aggregate; When the metal M is Fe, the stable oxide aggregate is a Fe2O3 aggregate; or, When the metal M is Cu, the stable oxide aggregate is a CuO aggregate; Wherein, when the metal element M is Co, Mn, Fe or Cu, the electron binding energy of the metal element M is 2p. 3 / 2 The binding energy of electrons.

13. The method according to claim 1, characterized in that, In the composite catalytic material, the molar ratio of the framework heteroatom elements to silicon elements is (0.002~0.05):1; The molar ratio of metallic element M to silicon is (0.001~0.25):

1.

14. The method according to claim 13, characterized in that, In the composite catalytic material, the molar ratio of the framework heteroatom elements to silicon elements is (0.003~0.045):1; The molar ratio of metallic element M to silicon is (0.002~0.15):

1.

15. The method according to claim 1, characterized in that, The composite catalytic material has a BET specific surface area of ​​400~800 m². 2 / g, with a total pore volume of 0.3~0.65mL / g, a micropore volume of 0.1~0.19mL / g, and a mesopore volume of 0.2~0.46mL / 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 0.5~5.5nm.

16. The method according to claim 1, characterized in that, The electron binding energy of the metal element M in the product obtained by calcining the crystallized product is denoted as T3. The electron binding energy of the metal element M in the crystallized product is denoted as T4; The calcination treatment makes T0', as defined by the following formula (2), any value between 0.4 and 0.8 eV; T0' = T3-T4 (2).

17. The method according to claim 1, characterized in that, In step S1, the molar ratio of the silicon source (calculated as SiO2): template agent: framework heteroatom precursor (calculated as heteroatom element Q): water: metal element M: silanizing agent is 1: (0.001~1): (0.002~0.05): (5~100): (0.001~0.25): (0.015~0.4).

18. The method according to claim 17, characterized in that, The molar ratio of the silicon source (calculated as SiO2): template agent: framework heteroatom precursor (calculated as heteroatom element Q): water: metal element M: silanizing agent is 1: (0.001~1): (0.003~0.045): (5~100): (0.002~0.15): (0.025~0.3).

19. The method according to claim 1, characterized in that, The molar ratio of nitrogen-containing ligand to metal element M is (0.5~5):

1.

20. The method according to claim 1, characterized in that, The mixing conditions in step c include stirring at 20~80℃ for 0.5~2 hours.

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

22. The method according to claim 21, characterized in that, The silicon source is selected from at least one of organosilicon grease, solid silica gel, and precipitated silica.

23. The method according to claim 22, characterized in that, The silicon source is an organosilicone grease, and the organosilicone grease has the general formula shown in formula (A): （A）； Where R a R b R c R d Each is independently selected from alkyl groups having 1 to 6 carbon atoms, wherein the alkyl group is a branched or straight-chain alkyl group.

24. The method according to claim 23, characterized in that, R a R b R c R d Each is independently selected from straight-chain alkyl groups having 1 to 4 carbon atoms or branched alkyl groups having 3 to 4 carbon atoms.

25. The method according to claim 24, characterized in that, The R a R b R c R d Each is independently selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, or tert-butyl.

26. The method according to claim 23, characterized in that, The silicone grease is selected from one or more of tetramethyl silicate, tetraethyl silicate, tetrabutyl silicate, and dimethyl diethyl silicone grease.

27. The method according to claim 1, characterized in that, The template agent is an organic base.

28. The method according to claim 27, characterized in that, The template agent is selected from at least one of quaternary ammonium bases, aliphatic amines, and aliphatic alcoholic amines.

29. The method according to claim 28, characterized in that, The template agent is selected from at least one of the quaternary ammonium bases with the structure shown in formula (B) below: (B); wherein R1, R2, R3 and R4 are each selected from alkyl groups having 1 to 4 carbon atoms.

30. The method according to claim 29, characterized in that, R1, R2, R3 and R4 are each selected from straight-chain alkyl groups having 1 to 4 carbon atoms and branched alkyl groups having 3 to 4 carbon atoms.

31. The method according to claim 30, characterized in that, R1, R2, R3 and R4 are each selected from at least one of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl and tert-butyl.

32. The method according to claim 29, characterized in that, The molecular sieve in the composite catalytic 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 The molecular sieve in 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 The molecular sieve in the composite catalytic material is a Beta-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.

33. The method according to claim 1, characterized in that, In step a, the silicon source is an organosilicone grease. After mixing the template agent, organosilicone grease, framework heteroatom precursor and water, the process further includes hydrolysis and alcohol removal treatment to obtain the hydrolysate solution. The conditions for the hydrolysis and alcohol removal treatment include: stirring and hydrolyzing at 0~95℃ for 2~10 hours.

34. The method according to claim 33, characterized in that, The conditions for the hydrolysis and alcohol removal treatment include: stirring and hydrolyzing at 50–95°C for 2–8 hours.

35. The method according to claim 1, characterized in that, In step S1, the skeletal heteroatom precursor includes at least one of an organic skeletal heteroatom precursor and an inorganic skeletal heteroatom precursor; the inorganic skeletal heteroatom precursor is at least one selected from chlorides, nitrates, and sulfates containing heteroatom element Q; the organic skeletal heteroatom precursor is an organic ester containing heteroatom element Q, selected from at least one structure with the general formula shown in formula (C) below: （C）； R5, R6, R7 and R8 are each selected from alkyl groups having 1 to 6 carbon atoms.

36. The method according to claim 35, characterized in that, R5, R6, R7 and R8 are each selected from straight-chain alkyl groups having 1 to 4 carbon atoms and branched alkyl groups having 3 to 6 carbon atoms.

37. The method according to claim 35, characterized in that, R5, R6, R7 and R8 are each selected from straight-chain alkyl groups having 2 to 4 carbon atoms and branched alkyl groups having 2 to 4 carbon atoms.

38. The method according to claim 35, characterized in that, R5, R6, R7 and R8 are each selected from one of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, isopentyl, hexyl or isohexyl.

39. The method according to claim 38, characterized in that, R5, R6, R7 and R8 are each independently selected from one of ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl or tert-butyl.

40. The method according to claim 35, characterized in that, The skeletal heteroatom is titanium, and the skeletal heteroatom precursor is selected from one or more of titanium tetrachloride, titanium sulfate, titanium nitrate, tetraethyl titanate, tetrapropyl titanate, and tetrabutyl titanate; the skeletal heteroatom is boron, and the skeletal heteroatom precursor is selected from one or more of boric acid and borate; the skeletal heteroatom is tin, and the skeletal heteroatom precursor is selected from one or more of tin halide, stannous halide, stannous sulfate, stannous sulfate, stannate, stannous nitrate, tin oxide, and stannous oxide.

41. The method according to claim 1, characterized in that, In step S1, the precursor of metal M is one or more of inorganic metal compounds and organometallic compounds; the inorganic metal compound is a water-soluble inorganic salt of metal element M; the water-soluble inorganic salt of metal element M is selected from one or more of chloride, hydrated chloride, sulfate, hydrated sulfate and nitrate of metal element M; the organometallic compound is an organic ligand compound of metal element M.

42. The method according to claim 41, characterized in that, The precursor of metal M is a water-soluble inorganic salt of the metal element M.

43. The method according to claim 41, characterized in that, The metal M precursor is an aqueous solution of the metal M precursor, wherein the molar ratio of metal element M to water in the aqueous solution of the metal M precursor is 1:(50~500).

44. The method according to claim 1, characterized in that, In step S1, the nitrogen-containing ligand is an alkylamine compound containing only an amino group or an amine compound containing other coordinating groups, wherein the other coordinating groups include one or more of hydroxyl, carboxyl, carbonyl, and mercapto groups.

45. The method according to claim 44, characterized in that, The nitrogen-containing ligand is one or more of the following: alkylamine compounds containing only an amino group having the structure shown in formula (D), alcoholamine compounds having the structure shown in formula (E), and aminocarboxylic acid compounds having the structure shown in formula (F): R9(NH2) n Formula (D); Wherein, n is 1 or 2; when n is 1, R9 is an alkyl group with 1 to 6 carbon atoms; when n is 2, R9 is an alkylene group with 1 to 6 carbon atoms. (HOR 10 ) m NH (3m) Equation (E); Where R 10 It is an alkylene group with 1 to 4 carbon atoms; m is 1, 2 or 3, and when m is greater than 1, multiple R 10 Same or different; (HOOCR 11 ) x NH (3x) Formula (F); Where R 11 It is an alkylene group with 1 to 4 carbon atoms; x is 1, 2, or 3. When x is greater than 1, multiple R 11 Same or different.

46. ​​The method according to claim 45, characterized in that, When n is 1, R9 is a straight-chain alkyl group with 1 to 6 carbon atoms and a branched alkyl group with 3 to 6 carbon atoms.

47. The method according to claim 46, characterized in that, When n is 1, R9 is one of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, neopentyl, isopentyl, tert-pentyl, and n-hexyl.

48. The method according to claim 45, characterized in that, When n is 2, R9 is a straight-chain alkylene with 1 to 6 carbon atoms and a branched alkylene with 3 to 6 carbon atoms.

49. The method according to claim 48, characterized in that, When n is 2, R9 is one of methylene, ethylene, n-propylene, n-butylene, n-pentylene, and n-hexylene.

50. The method according to claim 45, characterized in that, R 10 It is one of methylene, ethylene, n-propylene, and n-butylene.

51. The method according to claim 45, characterized in that, R 11 It is one of methylene, ethylene, n-propylene, and n-butylene.

52. The method according to claim 45, characterized in that, The nitrogen-containing ligand is selected from one or more of ethylamine, ethylenediamine, ethanolamine, and ethylenediaminetetraacetic acid.

53. The method according to claim 1, characterized in that, In step S1, the general formula of the silanizing agent is R. 12 Si(R 13 (R) 14 )R 15 , where R 12 R 13 R 14 R 15 Each group is independently a halogen, alkyl, alkoxy, aromatic, or amino group, and R 12 R 13 R 14 R 15 At least one of them is an alkyl, alkoxy, aromatic or amino group; the alkyl, alkoxy and amino groups each have 1 to 18 carbon atoms, and the aromatic group has 6 to 18 carbon atoms.

54. The method according to claim 53, characterized in that, The silanizing agent is selected from one or more of dimethyldichlorosilane, N-phenyl-3-aminopropyltrimethoxysilane, phenyltrimethoxysilane, hexadecyltrimethoxysilane, octyltriethoxysilane, 3-aminopropyltrimethoxysilane, and N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane.

55. The method according to claim 54, characterized in that, The silanizing agent is at least one of N-phenyl-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, and N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane.

56. The method according to claim 1, characterized in that, In step S2, the conditions for the hydrothermal crystallization treatment include: being carried out under autogenous pressure, a hydrothermal crystallization time of 0.5 to 10 days, and a hydrothermal crystallization temperature of 110 to 200°C. The conditions for the calcination treatment include: a calcination temperature of 400~900℃ and a calcination time of 1~16 hours.

57. The method according to claim 56, characterized in that, The conditions for the hydrothermal crystallization treatment include: being carried out under autogenous pressure, a hydrothermal crystallization time of 0.5 to 5 days, and a hydrothermal crystallization temperature of 150 to 200°C; The conditions for the roasting treatment include: a roasting temperature of 400~800℃ and a roasting time of 2~8 hours.

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