Metal organic framework, preparation method thereof and 2, 5-dimethylfuran hydrolysis method

Abstract

The invention relates to the field of catalysis, in particular to a metal organic framework, a preparation method of the metal organic framework and a method for hydrolyzing 2, 5-dimethylfuran. The metal organic framework comprises a polyoxometallate component, the contact angle between the metal organic framework and water is more than 80 degrees, the total acid content is 150-700 [mu] mol.g <-1 >, the morphology is a polyhedron, and the length of any edge is not less than 3 [mu] m. The metal organic framework provided by the invention contains a polyoxometallate component, the contact angle between the polyoxometallate component and water is more than 80 degrees, the metal organic framework is a polyhedron, the length of any edge is not less than 3 microns, and the metal organic framework with the characteristics has unique acid property and hydrophobic property and excellent hydrolytic activity.

Description

Technical Field

[0001] The invention relates to the field of catalysis, and in particular to a metal organic framework and a preparation method thereof, and a method for hydrolyzing 2,5-dimethylfuran. Background Art

[0002] Entering the 21st century, biomass, a renewable resource, has received more and more attention, and it has the potential to replace non-renewable resources such as petroleum. The utilization methods of natural biomass organic molecules are constantly being developed, and more and more biomass platform compounds have entered people's field of vision.

[0003] 2,5-Hexanedione (HDO) is an important organic chemical intermediate and is widely used in medicine, fragrance, pesticide, photographic agent, electroplating and spray painting, etc. HDO has a relatively active chemical property. As an important biomass platform compound, it is used in the production of many high-value fine chemicals, such as bio-based PX, MCPD, N-substituted pyrrole, N-substituted tetrahydropyrrole, 2,5-dimethyltetrahydrofuran, etc.

[0004] The current production routes of HDO mainly include: 1. Hydrolysis and decarboxylation of acetoacetic acid esters; 2. Hydrolysis of cellulose, sugars, 5-hydroxymethylfurfural (HMF) and other raw materials; 3. Preparation by catalytic conversion reaction of polyhydroxy compounds including glycerol; 4. Obtained by hydrolysis of 2,5-dimethylfuran. The four current synthesis methods all have certain defects, such as the high cost of catalysts and raw materials, and the need to be carried out under acidic or alkaline conditions, which seriously corrodes the equipment and has certain safety issues, or the high cost of raw materials for the coupling decarboxylation of ethyl acetoacetate, and the complicated operation process, which is not conducive to industrial expansion production.

[0005] CN112979436A discloses a method for preparing HDO, that is, 2,5-hexanedione is obtained by carbon growth-wacker oxidation reaction under the action of a catalyst and an oxidant, but this method requires the use of precious metals and the product is relatively complex and difficult to separate. The document [Chemistryselect, 2016, 1 (6): 1252-1255] reports a method for obtaining 2,5-hexanedione through a two-phase system using sulfuric acid as a catalyst. However, this method has the problems of being difficult to recover using a homogeneous acid catalyst, serious corrosion to the equipment, and causing a large amount of acidic pollutants. CN105439836B discloses a method for preparing 2,5-hexanedione by catalysis with a solid acid molecular sieve, and the method has the advantages of easy separation and no pollution. However, the catalyst molecular sieve used has a large water absorption, the reaction conditions are relatively harsh, and because the organic phase uses methyl isobutyl ketone with a high boiling point, it will cause problems such as high energy consumption for subsequent separation. Summary of the invention

[0006] The purpose of the present invention is to overcome the problems in the prior art of difficult catalyst recovery, high catalyst cost, poor catalyst selectivity and harsh catalytic reaction conditions in the preparation process of 2,5-hexanedione, and to provide a metal organic framework and a preparation method thereof and a method for hydrolyzing 2,5-dimethylfuran. The metal organic framework has the characteristics of low cost, good stability, easy recovery, high 2,5-hexanedione selectivity and mild reaction conditions.

[0007] In order to achieve the above object, the present invention provides a metal organic framework in a first aspect, wherein the metal organic framework comprises a polyoxometalate component, wherein the contact angle of the metal organic framework with water is above 80°, and the total acid content is 150-700 μmol·g -1 The shape is polyhedron, and the length of any edge is not less than 3μm.

[0008] The second aspect of the present invention provides a method for preparing the metal organic framework described in the first aspect, and the preparation method comprises the following steps: S1: a metal salt solution and an organic ligand solution are brought into first contact at a pH of 3-7, a polyoxometalate solution is added for second contact, and after contact, crystallization, a first separation, and a first drying are performed to obtain a precursor; S2: under an inert atmosphere, the precursor and a hydrophobic component are brought into third contact in an organic solvent, a second separation, and a second drying are performed.

[0009] A third aspect of the present invention provides a method for hydrolyzing 2,5-dimethylfuran, the method comprising: in a composite solvent system containing water and an organic solvent, contacting 2,5-dimethylfuran with a catalyst for reaction, wherein the catalyst comprises the metal organic framework described in the first aspect.

[0010] Through the above technical solution, the present invention has the following advantages:

[0011] The metal organic framework provided by the present invention contains a polyoxometalate component and has a contact angle with water of more than 80° and a total acid content of 150-700 μmol·g -1 , and the morphology is polyhedral, with any edge length not less than 3μm. The metal-organic framework with this feature has unique acidic and hydrophobic properties and excellent hydrolytic activity.

[0012] In the preparation method of the present invention, acid treatment, composite polyoxometalate (POMS) and hydrophobic treatment are used, which work synergistically to give MOF unique structural characteristics, acid content and water contact angle characteristics.

[0013] The metal organic framework of the present invention is applied to the hydrolysis of 2,5-dimethylfuran to prepare 2,5-hexanedione, the raw materials react on the surface pores of the MOF (metal organic framework), and the silanization post-treatment of the MOF increases the hydrophobicity of the surface pores around the polyanion, forming a hydrophobic channel, so that the small molecules after the reaction diffuse rapidly through the pores, and it is not easy to cause the self-polymerization reaction of the product to reduce the selectivity of the product. After the reaction is completed, the solid acid catalyst is easily separated from the reaction system by simple filtration, which is very friendly to the further separation of subsequent products. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a scanning electron microscope image (SEM) of the hydrophobic MOF-1 of Example 1;

[0015] Figure 2 is the contact angle between the hydrophobic MOF-1 and water in Example 1;

[0016] Figure 3 This is the N2- adsorption-desorption curve of the hydrophobic MOF-1 of Example 1;

[0017] Figure 4 This is a scanning electron microscope image (SEM) of the hydrophobic MOF-2 of Example 2;

[0018] Figure 5 Scanning electron microscope image (SEM) of hydrophobic MOF-1-1 of comparative example 1. DETAILED DESCRIPTION

[0019] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0020] The present invention provides a metal organic framework, which comprises a polyoxometalate component, wherein the contact angle between the metal organic framework and water is above 80°, and the total acid content is 150-700 μmol·g -1 The shape is polyhedron, and the length of any edge is not less than 3μm.

[0021] The metal organic framework provided by the present invention contains a polyoxometalate component and has a contact angle with water of more than 80° and a total acid content of 150-700 μmol·g -1 , and the morphology is polyhedral, with any edge length not less than 3μm. The metal-organic framework with this feature has unique acidic and hydrophobic properties and excellent hydrolytic activity.

[0022] According to a preferred embodiment of the present invention, the contact angle between the metal organic framework and water is 80-150°, preferably 80-120°. By adopting the above preferred solution, the catalytic activity of the material can be further improved.

[0023] According to a preferred embodiment of the present invention, the metal organic framework comprises a hydrophobic component, and the hydrophobic component is loaded on the surface of the metal organic framework.

[0024] In the present invention, the hydrophobic component has a wide range of options, for example, it can be a silane compound and an alkylamine compound. According to a preferred embodiment of the present invention, the hydrophobic component is a silane compound, preferably at least one of polydimethylsiloxane, hexadecyltrimethoxysilane, chlorosilane, dimethyldichlorosilane, phenyltrimethoxysilane, and diethoxydimethylsilane.

[0025] According to a preferred embodiment of the present invention, the metal organic framework has a hexagonal cross section and a crystal size of 3-20 μm.

[0026] According to a preferred embodiment of the present invention, the total acid content of the metal organic framework is 200-600 μmol·g -1 , more preferably 460-600 μmol·g -1 By adopting the above preferred embodiment, the catalytic activity of the material can be further improved.

[0027] According to a preferred embodiment of the present invention, the total specific surface area of ​​the metal organic framework is 400-900m 2 ·g -1 , preferably 650-900m 2 ·g -1 ;.

[0028] According to a preferred embodiment of the present invention, the external specific surface area of ​​the metal organic framework is 40-100m 2 ·g -1 , preferably 55-100m 2 ·g -1 .

[0029] According to a preferred embodiment of the present invention, the total pore volume of the metal organic framework is 0.3-1.0 cm 3 ·g -1 , for example, it can be 0.3 cm 3 ·g -1 、0.4cm 3 ·g -1 、0.5cm 3 ·g -1 、0.6cm3 ·g -1 、0.7cm 3 ·g -1 、0.8cm 3 ·g -1 、0.9cm 3 ·g -1 , 1.0cm 3 ·g -1 .

[0030] According to a preferred embodiment of the present invention, the micropore volume of the metal organic framework is 0.1-0.6 cm 3 ·g -1 , for example, it can be 0.1 cm 3 ·g -1 , 0.2cm 3 ·g -1 、0.3cm 3 ·g -1 、0.4cm 3 ·g -1 、0.5cm 3 ·g -1 、0.6cm 3 ·g -1 .

[0031] In the present invention, the polyoxometalate has a wide range of optional materials. According to a preferred embodiment of the present invention, the polyoxometalate component is selected from H4SiW 12 O 40 ·nH2O、H3PW 12 O 40 nH2O, H4SiMo 12 O 40 nH2O、H3PMo 12 O 40 nH2O and H3AsMo 12 O 40 At least one of nH2O. By adopting the above preferred embodiment, the catalytic activity of the MOF material can be further improved.

[0032] In the present invention, the metal element of the metal organic framework can be a conventional choice in the art. According to a preferred embodiment of the present invention, the metal element of the metal organic framework is selected from at least one of Zr, Cr, Fe, Co, Ni, Cu, Ag, Zn and Al, preferably at least one of Cu, Zr, Zn and Zr.

[0033] In the present invention, the organic ligands of the metal organic framework can be selected from a wide range, for example, they can be imidazole ligands and / or carboxylic acid ligands commonly used in the art. In order to further improve the effect of the present invention, the organic ligands of the metal organic framework in the present invention are carboxylic acid ligands.

[0034] According to a preferred embodiment of the present invention, the imidazole ligand is selected from at least one of imidazole, 2-methylimidazole, 2-nitroimidazole and 2-nitroimidazole derivatives.

[0035] According to a preferred embodiment of the present invention, the carboxylic acid ligand is selected from at least one of trimesic acid, terephthalic acid, 2-aminoterephthalic acid, phthalic acid, biphenyl-3,4,5-tricarboxylic acid, 1,4-naphthalene dicarboxylic acid, biphenyl dicarboxylic acid, and 3,3,5,5-biphenyltetracarboxylic acid.

[0036] The present invention provides a method for preparing the metal organic framework, which comprises the following steps:

[0037] S1: a metal salt solution and an organic ligand solution are first contacted at a pH of 3-7, a polyoxometalate solution is added for second contact, and after the contact, crystallization, first separation, and first drying are performed to obtain a precursor;

[0038] S2: Under an inert atmosphere, the precursor and the hydrophobic component are brought into contact with each other for the third time in an organic solvent, and then separated and dried for the second time.

[0039] In the present invention, the metal salt solution is a solution obtained by dissolving a metal in water, and the ratio of solvent water to metal salt is 5-500 mL solvent water / 1.0 g metal salt.

[0040] In the present invention, the organic ligand solution is a solution obtained by dissolving the organic ligand in an organic solvent, for example, at least one organic solvent selected from N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran, methanol, ethanol, propanol, butanol, n-butanol, and isopropanol.

[0041] In the present invention, the polyoxometalate solution is a solution obtained by dissolving polyoxometalate in an organic solvent, for example, at least one organic solvent selected from N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran, methanol, ethanol, propanol, butanol, n-butanol, and isopropanol.

[0042] In the present invention, the pH is controlled by a pH regulator, which is a weak acid and / or a medium-strong acid conventional in the art. According to a preferred embodiment of the present invention, the acid is selected from at least one of H3PO4, H2C2O4, HCOOH, CH COOH and HSiO. By adopting the above preferred embodiment, the active adsorption sites on the surface of the metal organic framework can be further increased or more defective cavities can be created, which can further improve the catalytic activity of the material.

[0043] According to a preferred embodiment of the present invention, the organic solvent in step S2 is selected from at least one of tetrahydrofuran, toluene, acetone, methyl isobutyl ketone, dichlorotoluene and dichloromethane.

[0044] According to a preferred embodiment of the present invention, the inert atmosphere is at least one of nitrogen atmosphere, helium and argon.

[0045] According to a preferred embodiment of the present invention, the method comprises a cooling step before the first separation and / or the second separation; and / or a washing step after the first separation and / or the second separation.

[0046] In the present invention, there is no particular limitation on the conditions of the first contacting, the second contacting, the third contacting, the crystallization, the cooling, the separation, the washing and the drying.

[0047] According to a preferred embodiment of the present invention, the conditions for the first contact include: a temperature of 25-85°C, preferably 30-70°C.

[0048] In the present invention, the first contact time is determined according to the contact temperature, as long as the reaction is complete. For example, the first contact time is 0.5-6h, preferably 1-3h.

[0049] In the present invention, the first contacting can be performed under stirring conditions, and the stirring speed is usually 100-900r / min.

[0050] According to a preferred embodiment of the present invention, the conditions for the first contact include: the molar ratio of the metal salt to the organic ligand is 1:(0.2-5).

[0051] According to a preferred embodiment of the present invention, the conditions for the second contact include: a temperature of 25-85°C, preferably 30-70°C.

[0052] In the present invention, the second contact time is determined according to the contact temperature, as long as the reaction is complete. For example, the first contact time is 0.5-6h, preferably 1-3h.

[0053] In the present invention, the second contacting can be performed under stirring conditions, usually at a stirring speed of 100-900 r / min.

[0054] According to a preferred embodiment of the present invention, the conditions for the second contact include: the molar ratio of the metal salt to the polyoxometalate is (5-150):1.

[0055] According to a preferred embodiment of the present invention, the crystallization conditions include: a temperature of 60-250°C, preferably 80-200°C.

[0056] According to a preferred embodiment of the present invention, the crystallization conditions include: a time of 3-48 hours, preferably 15-30 hours.

[0057] In the present invention, the crystallization can be carried out under stirring conditions, and the stirring speed is usually 100-600r / min.

[0058] According to a preferred embodiment of the present invention, the conditions for the third contact include: a temperature of 80-200°C, preferably 100-200°C.

[0059] According to a preferred embodiment of the present invention, the conditions for the third contact include: a time of 3-48 hours, preferably 5-24 hours.

[0060] According to a preferred embodiment of the present invention, the conditions for the third contact include: the molar concentration of the hydrophobic component in the organic solvent is 0.1-100 mmol / L.

[0061] According to a preferred embodiment of the present invention, the conditions for the third contact include: the volume / mass ratio of the organic solvent to the precursor is (50-800) mL: 1 g, preferably (50-500) mL: 1 g.

[0062] According to a preferred embodiment of the present invention, the drying temperature of the first drying is 30-200° C. Optionally, the first drying is carried out in two stages, and the temperature difference between the two stages is 30-120° C. For example, the temperature of the first stage is 75° C. and the time is 4 hours, and the drying temperature of the second stage is 180° C. and the time is 12 hours.

[0063] According to a preferred embodiment of the present invention, the temperature of the second drying is 30-180°C.

[0064] The invention provides a method for hydrolyzing 2,5-dimethylfuran, which comprises: in a composite solvent system containing water and an organic solvent, 2,5-dimethylfuran is contacted with a catalyst for reaction, wherein the catalyst comprises the metal organic framework of the invention.

[0065] According to a preferred embodiment of the present invention, the organic solvent in the composite solvent system is a weak polar solvent, preferably at least one selected from toluene, methyl isobutyl ketone, cyclohexane, ethyl acetate, and tetrahydrofuran.

[0066] According to a preferred embodiment of the present invention, the composite solvent system contains a salt, preferably at least one selected from the group consisting of NaCl, Na2SO4, KCl, and K2SO.

[0067] According to a preferred embodiment of the present invention, the volume ratio of water to organic solvent in the composite solvent system is 0.05-2:1, preferably 0.08-0.3; the mass ratio of salt to water is 0.05-10:1.

[0068] According to a preferred embodiment of the present invention, the conditions of the contact reaction include: the reaction temperature is 100-220°C, preferably 120-200°C.

[0069] According to a preferred embodiment of the present invention, the conditions of the contact reaction include: the reaction time is 1-24h, preferably 4-16h.

[0070] In the present invention, the contact reaction can be carried out under stirring conditions, usually at a stirring speed of 200-1000 r / min, preferably 400-800 r / min.

[0071] According to a preferred embodiment of the present invention, the conditions of the contact reaction include: the mass ratio of 2,5-dimethylfuran to catalyst is 0.5-10:1, preferably 1-8:1.

[0072] The present invention will be described in detail below by way of examples. In the following examples, the raw materials are all commercially available products.

[0073] The reaction product N-substituted pyrrole compound was analyzed qualitatively and quantitatively by gas chromatography-mass spectrometry (GC-MS), and the conversion rate of the product soluble carbohydrate was analyzed by high performance liquid chromatography (HPLC). The gas chromatograph was Agilent 7890A of Agilent Corporation of the United States, the chromatographic column was HP-5 non-polar capillary column (30m, 0.53mm), the gas chromatograph was Agilent 7890B, the detector was hydrogen flame ionization detector (FID), and the chromatographic column was SE-54 capillary column (30m, 0.53mm). The high performance liquid chromatography was analyzed by Agilent 1200, and the chromatographic column was SHODEX SC1011 sugar column (8×300mm).

[0074] In the present invention, the contact angle measuring instrument is DSA100 of KRUSS Company, Germany. A tangent line of the gas-liquid interface is drawn from the intersection of the gas, liquid and solid phases, and the angle θ between the tangent line and the solid-liquid boundary line passing through the three-phase contact point is the contact angle of the liquid on the solid surface. When the gas is air, the solid is the modified MOF material, and the liquid is water, the measured contact angle is the contact angle between the modified MOF material and water, wherein the larger the contact angle, the better the relative hydrophobicity of the modified MOF catalyst.

[0075] In the present invention, the scanning electron microscope (SEM) photos of the samples were taken on a Hitachi S-4800II scanning electron microscope. The acceleration voltage of the instrument was 15 kV, and the samples were chrome-plated before analysis.

[0076] In the present invention, the test instrument and test method for the average pore size, specific surface area and pore volume of the sample are: physical adsorption measurement is performed by nitrogen at -196°C using a 3H-2000PM2 physical adsorption instrument to analyze the pore structure characteristics of each adsorption material sample. The initial degassing condition is: degassing operation at 150°C for 6 hours. After measuring the adsorption isotherm of nitrogen on the sample, the specific surface area is calculated using the BET (Brunauer-Emmett-Teller) method, and the pore volume and pore size distribution are calculated using the BJH (Barrett-Joyner-Halenda) method.

[0077] In the present invention, the acid content of the sample is determined by using the NH3-TPD chemical adsorption-desorption curve using the Altamira AMI-3300 instrument. Before the test, the sample is activated at 200°C for 1h, adsorbs ammonia at 100°C for 20min, and then desorbs and detects at 100-350°C. The acid content is calculated by Gaussian distribution peak separation and baseline adjustment.

[0078] The conversion rate formula of furan compounds takes 2,5-dimethylfuran as the substrate as an example:

[0079] Conversion rate of 2,5-dimethylfuran (%) = (molar amount of 2,5-dimethylfuran participating in the reaction) / (molar amount of 2,5-dimethylfuran as the reaction substrate) × 100%.

[0080] The calculation formula for the yield of product 2,5-hexanedione is, taking 2,5-dimethylfuran as the substrate as an example:

[0081] The yield of the product 2,5-hexanedione (%) = (the molar amount of 2,5-hexanedione produced by the reaction) / (the molar amount of the reaction substrate 2,5-dimethylfuran) × 100%.

[0082] The selectivity of the product 2,5-hexanedione (%) = (the molar amount of 2,5-hexanedione produced by the reaction) / (the molar amount of 2,5-dimethylfuran reacted) × 100%.

[0083] Example 1

[0084] Weigh 2.0 g of copper nitrate trihydrate and dissolve it in 80 mL of deionized water to obtain solution A. Weigh 1.6 g of trimesic acid and dissolve it in 40 mL of DMF and 40 mL of ethanol and stir thoroughly for 30 min to obtain solution B. Weigh H3PW 12 O 40 5H2O 0.2g was stirred thoroughly to form solution C, and solution A was dripped into solution B drop by drop, and the dripping speed was controlled at 1ml / min, while maintaining high-speed stirring. After the dripping was completed, acetic acid was added drop by drop until the pH of the solution was about 4.5 to obtain suspension D. Then, solution C was added drop by drop into suspension D, and the dripping speed was controlled at 0.5ml / min. Then the above system was transferred to a crystallization kettle and crystallized at 100℃ for 22h.

[0085] After crystallization, the mixture was cooled to room temperature, centrifuged to remove the mother liquor, and washed several times with ethanol. The drying was carried out in two stages, the temperature of the first stage was 75°C, the time was 4h, and the drying temperature of the second stage was 180°C, the time was 12h, and MOF-1 was obtained after drying.

[0086] 1.5 g of the prepared MOF-1 was weighed and placed in 150 mL of toluene, and phenyltrimethoxysilane was added to make the molar concentration 2 mM, and stirred at 120 ° C for 10 h under N2 atmosphere. The suspension was then centrifuged and washed three times with toluene, and then vacuum dried at 150 ° C for 12 h to obtain hydrophobic MOF-1.

[0087] The SEM image of the hydrophobic MOF-1 sample is shown in Figure 1 As shown, the polyhedral crystal form has an arbitrary edge length of no less than 3 μm and a hexagonal cross section. The total acid content of the sample is 533 μmol·g -1 The contact angle between the sample and water is 113.7°. Figure 2 The N2- adsorption-desorption curve of the sample is shown in Figure 3 , the pore structure data are shown in Table 1.

[0088] Example 2

[0089] Weigh 2.0 g of copper nitrate trihydrate and dissolve it in 80 mL of deionized water to obtain solution A. Weigh 1.6 g of trimesic acid and dissolve it in 40 mL of DMF and 40 mL of ethanol and stir thoroughly for 30 min to obtain solution B. Weigh H3PW 12 O 405H2O 0.2g was stirred thoroughly to form solution C. Solution A was dripped into solution B at 50°C, and the dripping speed was controlled at 1ml / min, while maintaining high-speed stirring. After the dripping was completed, acetic acid was added dropwise until the pH of the solution was about 4 to obtain suspension D. Then, solution C was added dropwise into suspension D, and the dripping speed was controlled at 0.5ml / min. The above system was then transferred to a crystallization kettle and crystallized at 100°C for 22h.

[0090] After crystallization, the mixture was cooled to room temperature, centrifuged to remove the mother liquor, and washed several times with ethanol. The drying was carried out in two stages, the temperature of the first stage was 75°C, the time was 4 hours, and the drying temperature of the second stage was 180°C, the time was 12 hours, and MOF-2 was obtained after vacuum drying.

[0091] 1.5 g of the prepared MOF-2 was weighed and placed in 150 mL of toluene, and chlorosilane was added to make the molar concentration 5 mM, and stirred at 120 ° C for 10 h under N2 atmosphere. The suspension was then centrifuged and washed three times with toluene, and then vacuum dried at 150 ° C for 12 h to obtain hydrophobic MOF-2.

[0092] The SEM image of hydrophobic MOF-2 is shown in Figure 4 As shown, any edge length is not less than 3 μm, and the cross section is hexagonal. The total acid content of the sample is 470 μmol·g -1 The contact angle between the sample and water is 110.3°. The pore structure data of the sample are shown in Table 1.

[0093] Example 3

[0094] Weigh 2.0 g of copper nitrate trihydrate and dissolve it in 80 mL of deionized water to obtain solution A. Weigh 1.6 g of trimesic acid and dissolve it in 40 mL of DMF and 40 mL of ethanol and stir thoroughly for 30 min to obtain solution B. Weigh H4SiW 12 O 40 0.2g was stirred thoroughly to form solution C. Solution A was dripped into solution B at 50°C, and the dripping speed was controlled at 1ml / min, while maintaining high-speed stirring. After the dripping was completed, acetic acid was added dropwise until the pH of the solution was about 3.5 to obtain suspension D. Then solution C was added dropwise to suspension D. Then solution C was added dropwise to turbid solution D, and the dripping speed was controlled at 0.5ml / min. Then the above system was transferred to a crystallization kettle and crystallized at 120°C for 22h.

[0095] After crystallization, the mixture was cooled to room temperature, centrifuged to remove the mother liquor, and washed several times with ethanol. The drying was carried out in two stages, the temperature of the first stage was 75°C, the time was 4 hours, and the drying temperature of the second stage was 180°C, the time was 12 hours, and MOF-3 was obtained after vacuum drying.

[0096] 1.5 g of the prepared MOF-3 was weighed and placed in 150 mL of toluene, and phenyltrimethoxysilane was added to make the molar concentration 2 mM, and stirred at 120 ° C for 10 h under N2 atmosphere. The suspension was then centrifuged and washed three times with toluene, and then vacuum dried at 150 ° C for 12 h to obtain hydrophobic MOF-3.

[0097] SEM and Figure 1 Similarly, any edge length is not less than 3 μm, and the cross section is hexagonal. The total acid content of the sample is 492 μmol·g -1 The contact angle between the sample and water is 110°. The pore structure data of the sample are shown in Table 1.

[0098] Example 4

[0099] Same as Example 1, except that other octadecylamine was used as the hydrophobic component. The SEM and Figure 1 The total acid content of the sample is 450 μmol·g -1 The contact angle of the sample with water is 105.5°. The pore structure data are shown in Table 1.

[0100] Example 5

[0101] Same as Example 1, except that H4GeW is used 12 O 40 nH2O as polyoxometalate, SEM and Figure 1 Similarly, any edge length is not less than 3 μm, and the cross section is hexagonal. The total acid content of the sample is 431 μmol·g -1 The contact angle between the sample and water is 98.7°. The pore structure data is shown in Table 1.

[0102] Example 6

[0103] Same as Example 1, except that imidazole was used as the ligand, and the total acid content of the hydrophobic MOF-6 sample was 395 μmol·g -1 The contact angle between the sample and water is 93.1°. The pore structure data is shown in Table 1.

[0104] Table 1

[0105]

[0106] Examples 7-12

[0107] With 2,5-dimethylfuran as the substrate, 0.3g of the hydrophobic MOF in the above Examples 1-6, 1.0g of 2,5-dimethylfuran, 10g of methyl isobutyl ketone and 2.0g of saturated sodium chloride aqueous solution were added to a stirred autoclave. 1MPa nitrogen was filled to prevent the organic solvent from boiling. The temperature was raised to the preset temperature using a programmed heating jacket, and then stirred using a magnetic stirrer. The reaction was carried out at 160°C for 10h, and the reaction solution was analyzed to obtain the conversion rate of 2,5-dimethylfuran and the yield of the target product 2,5-hexanedione, as shown in Table 2.

[0108] Table 2

[0109]

[0110] Example 13

[0111] With 2,5-dimethylfuran as substrate, methyl isobutyl ketone and water as solvent, 0.6g of the hydrophobic MOF-1 in Example 1, 1.0g of 2,5-dimethylfuran, 10g of methyl isobutyl ketone and 2.0g of saturated sodium chloride aqueous solution were added to a stirred autoclave. 1MPa nitrogen was filled to prevent the organic solvent from boiling. The heating jacket was heated to the preset temperature using a programmed temperature increase, and then stirred using a magnetic stirrer. The reaction was carried out at 160°C for 10h, and the reaction solution was analyzed to obtain the conversion rate of 2,5-dimethylfuran and the yield of the target product 2,5-hexanedione, as shown in Table 3.

[0112] Embodiment 14

[0113] With 2,5-dimethylfuran as substrate, methyl isobutyl ketone and water as solvent, 0.1g of the hydrophobic MOF-1 in Example 1, 1.0g of 2,5-dimethylfuran, 10g of methyl isobutyl ketone and 2.0g of saturated sodium chloride aqueous solution were added to a stirred autoclave. 1MPa nitrogen was filled to prevent the organic solvent from boiling. The heating jacket was heated to the preset temperature using a programmed temperature increase, and then stirred using a magnetic stirrer. The reaction was carried out at 160°C for 10h, and the reaction solution was analyzed to obtain the conversion rate of 2,5-dimethylfuran and the yield of the target product 2,5-hexanedione, as shown in Table 3.

[0114] Embodiment 15

[0115] With 2,5-dimethylfuran as substrate, methyl isobutyl ketone and water as solvent, 0.3g of the hydrophobic MOF-1 in Example 1, 1.0g of 2,5-dimethylfuran, 10g of methyl isobutyl ketone and 4.0g of saturated sodium chloride aqueous solution were added to a stirred autoclave. 1MPa nitrogen was filled to prevent the organic solvent from boiling. The heating jacket was heated to the preset temperature using a programmed temperature increase, and then stirred using a magnetic stirrer. The reaction was carried out at 160°C for 10h, and the reaction solution was analyzed to obtain the conversion rate of 2,5-dimethylfuran and the yield of the target product 2,5-hexanedione, as shown in Table 3.

[0116] Example 16

[0117] With 2,5-dimethylfuran as substrate, methyl isobutyl ketone and water as solvent, 0.3g of the hydrophobic MOF-1 in Example 1, 1.0g of 2,5-dimethylfuran, 10g of methyl isobutyl ketone and 2.0g of saturated sodium chloride aqueous solution were added to a stirred autoclave. 1MPa nitrogen was filled to prevent the organic solvent from boiling. The heating jacket was heated to the preset temperature using a programmed temperature increase, and then stirred using a magnetic stirrer. The reaction was carried out at 180°C for 10h, and the reaction solution was analyzed to obtain the conversion rate of 2,5-dimethylfuran and the yield of the target product 2,5-hexanedione, as shown in Table 3.

[0118] Embodiment 17

[0119] With 2,5-dimethylfuran as substrate, methyl isobutyl ketone and water as solvent, 0.3g of the hydrophobic MOF-1 in Example 1, 1.0g of 2,5-dimethylfuran, 10g of methyl isobutyl ketone and 2.0g of saturated sodium chloride aqueous solution were added to a stirred autoclave. 1MPa nitrogen was filled to prevent the organic solvent from boiling. The heating jacket was heated to the preset temperature using a programmed temperature increase, and then stirred using a magnetic stirrer. The reaction was carried out at 160°C for 15h, and the reaction solution was analyzed to obtain the conversion rate of 2,5-dimethylfuran and the yield of the target product 2,5-hexanedione, as shown in Table 3.

[0120] Embodiment 18

[0121] With 2,5-dimethylfuran as substrate, tetrahydrofuran (THF) and water as solvent, 0.3g of the hydrophobic MOF-1 in Example 1, 1.0g of 2,5-dimethylfuran, 10g of tetrahydrofuran and 2.0g of saturated sodium chloride aqueous solution were added to a stirred autoclave. 1MPa nitrogen was filled to prevent the organic solvent from boiling. The heating jacket was heated to a preset temperature using a programmed temperature increase, and then stirred using a magnetic stirrer. The reaction was carried out at 160°C for 10h, and the reaction solution was analyzed to obtain the conversion rate of 2,5-dimethylfuran and the yield of the target product 2,5-hexanedione, as shown in Table 3.

[0122] Embodiment 19

[0123] With 2,5-dimethylfuran as substrate, tetrahydrofuran and water as solvent, 0.3g of the hydrophobic MOF-1 in Example 1, 1.0g of 2,5-dimethylfuran, 10g of tetrahydrofuran and 4.0g of saturated sodium chloride aqueous solution were added to a stirred autoclave. 1MPa nitrogen was filled to prevent the organic solvent from boiling. The heating jacket was heated to the preset temperature using a programmed temperature increase, and then stirred using a magnetic stirrer. The reaction was carried out at 160°C for 10h, and the reaction solution was analyzed to obtain the conversion rate of 2,5-dimethylfuran and the yield of the target product 2,5-hexanedione, as shown in Table 3.

[0124] Embodiment 20

[0125] With 2,5-dimethylfuran as substrate, tetrahydrofuran and water as solvent, 0.3g of the hydrophobic MOF-1 in Example 1, 1.0g of 2,5-dimethylfuran, 10g of tetrahydrofuran and 1.0g of saturated sodium chloride aqueous solution were added to a stirred autoclave. 1MPa nitrogen was filled to prevent the organic solvent from boiling. The temperature was raised to the preset temperature using a programmed heating jacket, and then stirred using a magnetic stirrer. The reaction was carried out at 160°C for 10h, and the reaction solution was analyzed to obtain the conversion rate of 2,5-dimethylfuran and the yield of the target product 2,5-hexanedione, as shown in Table 3.

[0126] Table 3

[0127]

[0128] Embodiment 21

[0129] With 2,5-dimethylfuran as substrate, methyl isobutyl ketone (MIBK) and water as solvent, 0.3g of the hydrophobic MOF of Example 1, 1.0g of 2,5-dimethylfuran, 10g of methyl isobutyl ketone and 2.0g of deionized water were added to a stirred autoclave. 1MPa nitrogen was filled to prevent the organic solvent from boiling. The heating jacket was heated to the preset temperature using a programmed temperature increase, and then stirred using a magnetic stirrer. The reaction was carried out at 160°C for 10h, and the reaction solution was analyzed to obtain a 2,5-dimethylfuran conversion rate of 75% and a 2,5-hexanedione yield of 70%.

[0130] Comparative Example 1

[0131] The same as Example 1, except that acetic acid was added to adjust the pH to 2 to obtain MOF-1-1.

[0132] 1.5 g of the prepared MOF-1-1 was weighed and placed in 150 mL of toluene, and phenyltrimethoxysilane was added to make the molar concentration 2 mM, and stirred at 120 ° C for 10 h under N2 atmosphere. The suspension was then centrifuged and washed three times with toluene, and then vacuum dried at 150 ° C for 12 h to obtain hydrophobic MOF-1-1.

[0133] The SEM image of the hydrophobic MOF-1-1 sample is shown in Figure 5 As shown, the material presents a flake morphology. The total acid content of the sample is 558 μmol·g -1 , the hydrophobic angle of the sample is about 108.2°.

[0134] With 2,5-dimethylfuran as substrate, methyl isobutyl ketone (MIBK) and water as solvent, 0.3g of the above hydrophobic MOF-1-1, 1.0g of 2,5-dimethylfuran, 10g of methyl isobutyl ketone and 2.0g of saturated sodium chloride aqueous solution were added to a stirred autoclave. 1MPa nitrogen was filled to prevent the organic solvent from boiling. The heating jacket was heated to the preset temperature using a programmed temperature increase, and then stirred using a magnetic stirrer. The reaction was carried out at 160°C for 10h, and the reaction solution was analyzed to obtain a 2,5-dimethylfuran conversion rate of 43% and a target product 2,5-hexanedione yield of 36%.

[0135] Comparative Example 2

[0136] The same as Example 1, except that no hydrophobic agent was added, to obtain MOF-1-2.

[0137] The total acid content of the sample is 480 μmol·g -1 ,When the hydrophobic angle test is conducted, the water droplets are quickly absorbed by the sample, and the sample is hydrophilic.

[0138] With 2,5-dimethylfuran as substrate, methyl isobutyl ketone (MIBK) and water as solvent, 0.3g of the above MOF-1-2, 1.0g of 2,5-dimethylfuran, 10g of methyl isobutyl ketone and 2.0g of saturated sodium chloride aqueous solution were added to a stirred autoclave. 1MPa nitrogen was filled to prevent the organic solvent from boiling. The heating jacket was heated to the preset temperature using a programmed temperature increase, and then stirred using a magnetic stirrer. The reaction was carried out at 160°C for 10h, and the reaction solution was analyzed to obtain a 2,5-dimethylfuran conversion rate of 61% and a target product 2,5-hexanedione yield of 52%.

[0139] Comparative Example 3

[0140] The same as Example 1, except that acetic acid was not added, to obtain MOF-1-3.

[0141] The total acid content of the sample is 130 μmol·g -1, the contact angle between the sample and water is 90°.

[0142] With 2,5-dimethylfuran as substrate, methyl isobutyl ketone (MIBK) and water as solvent, 0.3g of the above MOF-1-3, 1.0g of 2,5-dimethylfuran, 10g of methyl isobutyl ketone and 2.0g of saturated sodium chloride aqueous solution were added to a stirred autoclave. 1MPa nitrogen was filled to prevent the organic solvent from boiling. The heating jacket was heated to the preset temperature using a programmed temperature increase, and then stirred using a magnetic stirrer. The reaction was carried out at 160°C for 10h, and the reaction solution was analyzed to obtain a 2,5-dimethylfuran conversion rate of 55% and a target product 2,5-hexanedione yield of 51%.

[0143] Comparative Example 4

[0144] Same as Example 1, except that H3PW is not added 12 O 40 5H2O to obtain MOF-1-3.

[0145] The total acid content of the sample is 105 μmol·g -1 The contact angle between the sample and water is 83°

[0146] With 2,5-dimethylfuran as substrate, methyl isobutyl ketone (MIBK) and water as solvent, 0.3g of the above MOF-1-4, 1.0g of 2,5-dimethylfuran, 10g of methyl isobutyl ketone and 2.0g of saturated sodium chloride aqueous solution were added to a stirred autoclave. 1MPa nitrogen was filled to prevent the organic solvent from boiling. The heating jacket was heated to the preset temperature using a programmed temperature increase, and then stirred using a magnetic stirrer. The reaction was carried out at 160°C for 10h, and the reaction solution was analyzed to obtain a 2,5-dimethylfuran conversion rate of 43% and a target product 2,5-hexanedione yield of 40%.

[0147] Comparative Example 5

[0148] 2.0 g of copper nitrate trihydrate was weighed and dissolved in 80 mL of deionized water to obtain solution A. 1.6 g of trimesic acid was weighed and added to 40 mL of DMF and 40 mL of ethanol and stirred for 30 min to obtain solution B. The above system was then transferred to a crystallization kettle and crystallized at 100° C. for 22 h.

[0149] After crystallization, the mixture was cooled to room temperature, centrifuged to remove the mother liquor, and washed several times with ethanol. The drying was carried out in two stages, the temperature of the first stage was 75°C, the time was 4 hours, and the drying temperature of the second stage was 180°C, the time was 12 hours, and MOF-1-5 was obtained after drying.

[0150] The total acid content of sample MOF-1-5 is 89 μmol·g -1,When the hydrophobic angle test is conducted, the water droplets are quickly absorbed by the sample, and the sample is hydrophilic.

[0151] With 2,5-dimethylfuran as substrate, methyl isobutyl ketone (MIBK) and water as solvent, 0.3g of the above MOF-1-5, 1.0g of 2,5-dimethylfuran, 10g of methyl isobutyl ketone and 2.0g of saturated sodium chloride aqueous solution were added to a stirred autoclave. 1MPa nitrogen was filled to prevent the organic solvent from boiling. The heating jacket was heated to the preset temperature using a programmed temperature increase, and then stirred using a magnetic stirrer. The reaction was carried out at 160°C for 10h, and the reaction solution was analyzed to obtain a 2,5-dimethylfuran conversion rate of 25% and a target product 2,5-hexanedione yield of 18%.

[0152] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A metal organic framework, characterized in that The metal organic framework comprises a polyoxometalate component, the contact angle between the metal organic framework and water is above 80°, and the total acid content is 150-700 μmol·g -1 The shape is polyhedron, and the length of any edge is not less than 3μm.

2. The metal organic framework according to claim 1, wherein The contact angle between the metal organic framework and water is 80-150°, preferably 80-120°.

3. The metal organic framework according to claim 1 or 2, wherein: The metal organic framework comprises a hydrophobic component, and the hydrophobic component is supported on the surface of the metal organic framework. Preferably, The hydrophobic component is a silane compound, preferably at least one of polydimethylsiloxane, hexadecyltrimethoxysilane, chlorosilane, dimethyldichlorosilane, phenyltrimethoxysilane, and diethoxydimethylsilane.

4. The metal organic framework according to any one of claims 1 to 3, wherein: The metal organic framework has a hexagonal cross section and a crystal size of 3-20 μm; and / or The total acid content of the metal organic framework is 200-600 μmol·g -1 ; and / or The total specific surface area of ​​the metal organic framework is 400-900m 2 ·g -1 ; preferably 650-900m 2 ·g -1 ; and / or The external specific surface area of ​​the metal organic framework is 40-100m 2 ·g -1 ; preferably 55-100m 2 ·g -1 and / or The total pore volume of the metal organic framework is 0.3-1.0 cm 3 ·g -1 ; and / or The micropore volume of the metal organic framework is 0.1-0.6 cm 3 ·g -1 .

5. The metal organic framework according to any one of claims 1 to 4, wherein: The polyoxometalate component is selected from H4SiW 12 O 40 ·nH2O、H3PW 12 O 40 nH2O, H4SiMo 12 O 40 nH2O(0.2g), H3PMo 12 O 40 nH2O and H3AsMo 12 O 40 At least one of nH2O.

6. The metal organic framework according to any one of claims 1 to 5, wherein: The metal element of the metal organic framework is selected from at least one of Zr, Cr, Fe, Co, Ni, Cu, Ag, Zn and Al, preferably at least one of Cu, Zr, Zn and Zr; and / or The organic ligand of the metal organic framework is a carboxylic acid ligand, preferably at least one selected from trimesic acid, terephthalic acid, 2-aminoterephthalic acid, phthalic acid, biphenyl-3,4,5-tricarboxylic acid, 1,4-naphthalene dicarboxylic acid, biphenyl dicarboxylic acid, and 3,3,5,5-biphenyl tetracarboxylic acid.

7. The method for preparing a metal organic framework according to any one of claims 1 to 6, characterized in that: The preparation method comprises the following steps: S1: a metal salt solution and an organic ligand solution are first contacted at a pH of 3-7, a polyoxometalate solution is added for second contact, and after the contact, crystallization, first separation, and first drying are performed to obtain a precursor; S2: Under an inert atmosphere, the precursor and the hydrophobic component are contacted for the third time in an organic solvent, separated for the second time, and dried for the second time; Preferably, The pH is controlled by a pH regulator, wherein the pH regulator is selected from at least one of H3PO4, H2C2O4, HCOOH, CH COOH and HSiO; and / or The organic solvent in step S2 is selected from at least one of tetrahydrofuran, toluene, acetone, methyl isobutyl ketone, dichlorotoluene and dichloromethane.

8. The preparation method according to claim 7, wherein: The conditions of the first contact include: a temperature of 25-85° C., preferably 30-70° C.; and / or a molar ratio of the metal salt to the organic ligand of 1:(0.2-5); and / or The conditions of the second contacting include: a temperature of 25-85° C., preferably 30-70° C.; and / or a molar ratio of the metal salt to the polyoxometalate of (5-150):1; and / or The crystallization conditions include: a temperature of 60-250° C., preferably 80-200° C.; and / or a time of 3-48 hours, preferably 15-30 hours; and / or The conditions for the third contact include: a temperature of 80-200°C, preferably 100-200°C; and / or a time of 3-48h, preferably 5-24h; and / or a molar concentration of the hydrophobic component in the organic solvent of 0.1-100mmol / L; and / or a volume / mass ratio of the organic solvent to the precursor of (50-800)mL:1g, preferably (50-500)mL:1g.

9. A method for hydrolyzing 2,5-dimethylfuran, characterized in that: The method comprises: in a composite solvent system containing water and an organic solvent, 2,5-dimethylfuran is contacted with a catalyst for reaction; The catalyst comprises the metal organic framework according to any one of claims 1 to 6; Preferably, The organic solvent in the composite solvent system is a weak polar solvent, preferably at least one selected from toluene, methyl isobutyl ketone, cyclohexane, ethyl acetate, and tetrahydrofuran; and / or The composite solvent system contains a salt, preferably at least one selected from NaCl, Na2SO4, KCl, K2SO4; and / or The volume ratio of water to organic solvent in the composite solvent system is 0.05-2:1, preferably 0.08-0.3:1; the mass ratio of salt to water is 0.05-10:

1.

10. The method according to claim 9, wherein: The conditions of the contact reaction include: The reaction temperature is 100-220°C, preferably 120-200°C; and / or The reaction time is 1-24h, preferably 4-16h; and / or The mass ratio of 2,5-dimethylfuran to the catalyst is 0.5-10:1, preferably 1-8:1.

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