A modified metal-organic framework material, its preparation method and application

Abstract

This invention relates to the field of catalyst technology for the hydrogenation of carbon dioxide to methanol, and discloses a modified metal-organic framework material and its preparation method and application. The method includes: (1) reacting a first inorganic metal compound, an aromatic organic acid, an organic acid, and a first organic solvent, followed by solid-liquid separation to obtain product I; (2) mixing product I, a second organic solvent, and a second inorganic metal compound, followed by solid-liquid separation to obtain product II; (3) mixing product II, a second organic solvent, and a metal-organic compound, followed by solid-liquid separation to obtain product III; (4) reacting product III, a Lewis acid compound, a second organic solvent, and a modifier; wherein the first inorganic metal compound and the second inorganic metal compound are different, the aromatic organic acid and the organic acid are different, and the modifier is selected from at least one of haloalkanes, alcohols, and alkenes. The material prepared by this method exhibits a methanol selectivity greater than 95% and a CO2 conversion rate greater than 25%.

Description

Technical Field

[0001] This invention relates to the field of catalysts for the hydrogenation of carbon dioxide to methanol, specifically to a modified metal-organic framework material and its preparation method and application. Background Technology

[0002] Methanol, as an energy carrier, is considered a chemical that can replace traditional fossil fuels. It is also an intermediate raw material for many chemical products, playing a vital role in industries such as pesticides, pharmaceuticals, automobiles, and defense. Currently, most methanol synthesis still utilizes fossil fuels, via syngas catalytic pathways, resulting in the generation and emission of large amounts of CO2. Considering that fossil fuels are produced through natural hydrocarbon reactions, utilizing the catalytic hydrogenation of CO2 to produce high-value-added products like methanol is more significant for carbon reduction. This new synthetic route for methanol production via CO2 hydrogenation plays a crucial role in the development of clean energy and carbon reduction.

[0003] Catalysts are crucial for the hydrogenation of CO2 to methanol. The activity, stability, and cost of the catalyst largely determine the yield, purity, and economic viability of the CO2 hydrogenation technology. In recent years, many researchers have conducted extensive work on the preparation and modification of CO2 hydrogenation catalysts, some of which have been used in pilot-scale and demonstration plants. Cu-based catalysts are the most common CO2 hydrogenation catalysts. Because Cu has a strong adsorption capacity for CO2 and can readily activate H2 into atomic *H, CO2 can react with surface atomic *H at relatively low temperatures and pressures to generate the intermediate product formate, which is then hydrogenated to methanol via the Eley-Rideal mechanism. However, Cu-based catalysts also have significant drawbacks. Due to the limited number of basic sites, the single-pass conversion rate of CO2 and the selectivity for methanol are relatively low. Another type of CO2 hydrogenation catalyst is the noble metal / rare metal catalyst, including palladium-based and indium-based catalysts. The addition of the noble metal Au can promote the dispersion and reduction of copper particles. These catalysts have a large number of basic sites and exhibit strong catalytic activity at high temperatures. The disadvantages are the scarcity and high price of precious metal resources. A research team led by Professor Deng Dehui at the Dalian Institute of Chemical Physics, Chinese Academy of Sciences, in collaboration with Professor Wang Ye's team at Xiamen University, achieved low-temperature, high-efficiency, and long-life catalytic hydrogenation of CO2 to methanol using a few-layer molybdenum disulfide catalyst rich in sulfur vacancies. In a small-scale laboratory test, the single-pass conversion rate of CO2 at 180℃ reached 12.5%, and the methanol selectivity reached 94.3%. The catalyst exhibits strong catalytic activity, low reaction temperature, and high methanol selectivity. The disadvantage is the low mechanical properties of the catalyst.

[0004] CN113368861A discloses a catalyst for the hydrogenation of carbon dioxide to methanol, its preparation method, and its application. The preparation method includes: firstly, mixing copper, zinc, and zirconium sources and adding citric acid and a surfactant, followed by grinding to obtain a catalyst precursor; then, subjecting the catalyst precursor to drying and calcination processes sequentially to obtain the catalyst for the hydrogenation of carbon dioxide to methanol. This invention achieves a CO2 conversion rate of less than 20% and a methanol selectivity of less than 50%.

[0005] CN103721719A discloses a catalyst for the hydrogenation of carbon dioxide to methanol, containing Cu, Zn, Al, X, halogens, and oxygen elements, and composed of oxides and halide-containing compounds. X is one or a combination of elements selected from Li, K, Mg, B, Ga, In, transition metals, and rare earth metals. The method described in this invention achieves a CO2 conversion rate of less than 30% and a methanol selectivity of less than 60%.

[0006] As can be seen from the above, the selectivity of the carbon dioxide hydrogenation catalyst for methanol synthesis prepared in the prior art is low. Summary of the Invention

[0007] The purpose of this invention is to overcome the problem of low selectivity of methanol in existing carbon dioxide hydrogenation catalysts for methanol synthesis, and to provide a modified metal-organic framework material, its preparation method and application. The modified metal-organic framework material prepared by this method has high methanol selectivity and CO2 conversion rate, with methanol selectivity greater than 95% and CO2 conversion rate greater than 25%.

[0008] To achieve the above objectives, the present invention provides a method for preparing modified metal-organic framework materials, the method comprising the following steps:

[0009] (1) The first inorganic metal compound, the aromatic organic acid, the organic acid and the first organic solvent are reacted and separated into solid and liquid components to obtain product I;

[0010] (2) Mix product I, the second organic solvent, and the second inorganic metal compound, and then separate the solid and liquid phases to obtain product II;

[0011] (3) Mix product II, the second organic solvent and the organometallic compound, and separate the solid and liquid to obtain product III;

[0012] (4) The product III, Lewis acid compound, second organic solvent and modifier are reacted to obtain modified metal-organic framework material;

[0013] Wherein, the first inorganic metal compound and the second inorganic metal compound are different, the aromatic organic acid and the organic acid are different, and the modifier is selected from at least one of haloalkanes, alcohols and alkenes.

[0014] Preferably, both the first inorganic metal compound and the second inorganic metal compound are selected from at least one of zirconium chloride, zirconium fluoride, zirconium oxychloride octahydrate, cerium nitrate, cerium nitrate hexahydrate, cerium chloride, cobalt nitrate, nickel nitrate hexahydrate, nickel nitrate, nickel chloride hexahydrate, cobalt nitrate hexahydrate, ytterbium chloride, ferrous chloride tetrahydrate, tin chloride pentahydrate, copper chloride, copper sulfate, copper nitrate, cuprous oxide, cuprous chloride, aluminum chloride, and magnesium chloride.

[0015] Preferably, the first inorganic metal compound is selected from at least one of zirconium chloride, zirconium fluoride, zirconium oxychloride octahydrate, cerium nitrate, cerium nitrate hexahydrate, cerium chloride, cobalt nitrate, nickel nitrate hexahydrate, nickel nitrate, nickel chloride hexahydrate, cobalt nitrate hexahydrate, ytterbium chloride, ferrous chloride tetrahydrate, and tin chloride pentahydrate, and more preferably at least one of zirconium chloride, zirconium fluoride, and cerium chloride.

[0016] Preferably, the second inorganic metal compound is selected from at least one of copper chloride, copper sulfate, copper nitrate, cuprous oxide, cuprous chloride, aluminum chloride, and magnesium chloride.

[0017] Preferably, the aromatic organic acid is selected from at least one of 4,4'-biphenyldicarboxylic acid, 2,2'-bipyridine-5,5'-dicarboxylic acid, triphenyldicarboxylic acid, pyridine-2,6-dicarboxylic acid, and 2,3-pyridine-dicarboxylic acid.

[0018] Preferably, the organic acid is selected from at least one of formic acid, acetic acid, propionic acid, butyric acid, octanoic acid, adipic acid, oxalic acid, malonic acid, succinic acid, maleic acid, tartaric acid, benzoic acid, phenylacetic acid, phthalic acid, terephthalic acid, valeric acid, hexanoic acid, decanoic acid, and stearic acid, and more preferably from at least one of formic acid, acetic acid, propionic acid, and oxalic acid.

[0019] Preferably, the first organic solvent is selected from at least one of N,N-dimethylformamide, N-methylpyrrolidone, acetonitrile, acetone, butanone, N,N-dimethylacetamide, and dimethyl sulfoxide.

[0020] Preferably, the second organic solvent is selected from at least one of tetrahydrofuran, acetone, petroleum ether, ethyl acetate, pyridine, methanol, and dichloromethane.

[0021] Preferably, the organometallic compound is selected from at least one of ethyl zinc, butyl zinc, methyl zinc, dibutyl zinc, and zinc butadiene.

[0022] Preferably, the Lewis acid compound is selected from at least one of ferric chloride, aluminum chloride, boron trifluoride, niobium pentachloride, and trifluoromethanesulfonate.

[0023] Preferably, in the haloalkane, the alkyl group is a straight-chain and / or branched alkyl group having 2-12 carbon atoms, and the halogen is at least one of Cl, F, I and Br;

[0024] Preferably, the haloalkane is selected from at least one of 1-chlorobutane, chloroisooctane, 1-chloropropane, chlorocyclopentane, 1-chlorooctane, and 1-chlorononane.

[0025] Preferably, the alcohol is an alkyl alcohol.

[0026] Preferably, the alcohol is selected from at least one of alkyl alcohols having 2-12 carbon atoms.

[0027] More preferably, the alcohol is selected from at least one of propanol, n-butanol, n-pentanol, n-heptanol, and n-octanol.

[0028] Preferably, the olefin has 2-12 carbon atoms;

[0029] Preferably, the olefin is selected from at least one of propylene, butene, pentene, heptenene, and octene.

[0030] Preferably, in step (1), the weight ratio of the first inorganic metal compound, the aromatic organic acid, and the organic acid is 1:0.2-5:5-200.

[0031] Preferably, in step (1), the reaction conditions include: a temperature of 100-200°C and a time of 5-30 hours.

[0032] In step (2), the weight ratio of product I and the second inorganic metal compound is 0.5-4:1.

[0033] Preferably, in step (2), the mixing conditions include a temperature of 20-35°C and a time of 5-24 hours.

[0034] Preferably, in step (3), the weight ratio of product II to organometallic compound is 0.5-5:1.

[0035] Preferably, in step (3), the mixing conditions include: a temperature of 20-35°C and a time of 0.5-10 hours.

[0036] In step (4), the weight ratio of product III, Lewis acid compound and modifier is 1:0.5-4:0.5-10.

[0037] Preferably, in step (4), the reaction conditions include: a temperature of 5-100°C and a time of 0.2-2 hours.

[0038] A second aspect of the present invention provides a modified metal-organic framework material prepared by the method described above.

[0039] A third aspect of the present invention provides the application of the modified metal-organic framework material described above as a catalyst for the hydrogenation of carbon dioxide to methanol.

[0040] The inventors of this invention have discovered that the activity and selectivity of CO2 hydrogenation catalysts are closely related to the interaction between the support and the active metal center. The support can not only stabilize ultrasmall metal nanoparticles or even single-point (atomic-level) catalytic centers, but also form unique interfacial structures with the active center, synergistically generating highly active interfacial sites. Metal-organic frameworks (MOFs) are porous solid materials constructed by linking metal-oxygen clusters as secondary building blocks with organic ligands, possessing characteristics such as tunable structure and high specific surface area. MOFs, as supports, can be used to design catalysts with clear structures and high active site density. Molecular catalysts stabilized in MOFs are no longer limited by the solubility of hydrogen in solution; simultaneously, the spatial separation of these active centers also improves their stability. This invention utilizes assembly techniques such as post-synthetic modification of ligands and secondary building blocks, functionalization of structural units, and non-covalent loading to solidify sub-nanometer or even atomic-level catalysts with CO2 hydrogenation catalytic activity within MOF materials, synthesizing composite metal-organic framework materials. By replacing traditional metal oxide supports with functionalized MOFs, strong metal-support interactions are introduced between metal nanoparticles, organic chelate ligands, and metal-oxygen cluster nodes, thereby optimizing catalytic activity and selectivity. This not only provides abundant interfaces and exhibits high chemoselectivity but also maintains catalytic activity over extended catalytic processes. Furthermore, by introducing hydrophobic alkyl long-chain groups, this invention modifies the hydrophobic properties of the catalyst support surface, inhibiting water molecule adsorption and improving the stability of the prepared modified metal-organic framework material as a catalyst. The carbon dioxide hydrogenation catalyst material provided by this invention achieves high product selectivity, greater than 95%, and a conversion rate greater than 20%. Detailed Implementation

[0041] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0042] The endpoints and any values ​​of the ranges disclosed herein 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 the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0043] The first aspect of this invention provides a method for preparing modified metal-organic framework materials, the method comprising the following steps:

[0044] (1) The first inorganic metal compound, the aromatic organic acid, the organic acid and the first organic solvent are reacted and separated into solid and liquid components to obtain product I;

[0045] (2) Mix product I, the second organic solvent, and the second inorganic metal compound, and then separate the solid and liquid phases to obtain product II;

[0046] (3) Mix product II, the second organic solvent and the organometallic compound, and separate the solid and liquid to obtain product III;

[0047] (4) The product III, Lewis acid compound, second organic solvent and modifier are reacted to obtain modified metal-organic framework material;

[0048] Wherein, the first inorganic metal compound and the second inorganic metal compound are different, the aromatic organic acid and the organic acid are different, and the modifier is selected from at least one of haloalkanes, alcohols and alkenes.

[0049] The steps (1), (2) and (3) of the method described in this invention prepare a metal-organic framework material containing three metal elements. Step (4) uses a specific modifier to perform hydrophobic modification on the metal-organic framework material obtained above, modifying the pyridine ring or benzene ring of the metal-organic framework material with alkyl chains, alcohol chains or olefin chains.

[0050] In this invention, the first inorganic metal compound and the second inorganic metal compound can be conventional choices in the art.

[0051] In a specific embodiment, both the first inorganic metal compound and the second inorganic metal compound are selected from at least one of zirconium chloride, zirconium fluoride, zirconium oxychloride octahydrate, cerium nitrate, cerium nitrate hexahydrate, cerium chloride, cobalt nitrate, nickel nitrate hexahydrate, nickel nitrate, nickel chloride hexahydrate, cobalt nitrate hexahydrate, ytterbium chloride, ferrous chloride tetrahydrate, tin chloride pentahydrate, copper chloride, copper sulfate, copper nitrate, cuprous oxide, cuprous chloride, aluminum chloride, and magnesium chloride.

[0052] Furthermore, in order to obtain a material containing multiple metals, the first inorganic metal compound and the second inorganic metal compound are different.

[0053] In a preferred embodiment, the first inorganic metal compound is selected from at least one of zirconium chloride, zirconium fluoride, zirconium oxychloride octahydrate, cerium nitrate, cerium nitrate hexahydrate, cerium chloride, cobalt nitrate, nickel nitrate hexahydrate, nickel nitrate, nickel chloride hexahydrate, cobalt nitrate hexahydrate, ytterbium chloride, ferrous chloride tetrahydrate, and tin chloride pentahydrate, more preferably at least one of zirconium chloride, zirconium fluoride, and cerium chloride.

[0054] In a preferred embodiment, the second inorganic metal compound is selected from at least one of copper chloride, copper sulfate, copper nitrate, cuprous oxide, cuprous chloride, aluminum chloride, and magnesium chloride.

[0055] In step (1) of this invention, a metal-organic framework material is prepared using two ligands, namely the aromatic organic acid and the organic acid, wherein the organic acid is different from the aromatic organic acid.

[0056] In a preferred embodiment, the aromatic organic acid is selected from at least one of 4,4'-biphenyldicarboxylic acid, 2,2'-bipyridine-5,5'-dicarboxylic acid, triphenyldicarboxylic acid, pyridine-2,6-dicarboxylic acid, and 2,3-pyridine-dicarboxylic acid.

[0057] In a preferred embodiment, the organic acid is selected from at least one of formic acid, acetic acid, propionic acid, butyric acid, octanoic acid, adipic acid, oxalic acid, malonic acid, succinic acid, maleic acid, tartaric acid, benzoic acid, phenylacetic acid, phthalic acid, terephthalic acid, valeric acid, hexanoic acid, decanoic acid, and stearic acid, preferably at least one of formic acid, acetic acid, propionic acid, and oxalic acid.

[0058] In this invention, the first organic solvent and the second organic solvent can be the same or different, as long as the reaction can proceed normally. To improve the reaction efficiency, it is preferable that the first organic solvent and the second organic solvent are different.

[0059] In this invention, there are no particular limitations on the amount of the first solvent and the second organic solvent, as long as they are sufficient to dissolve the reactants and allow for a normal reaction.

[0060] In a preferred embodiment, the first organic solvent is selected from at least one of N,N-dimethylformamide, N-methylpyrrolidone, acetonitrile, acetone, butanone, N,N-dimethylacetamide, and dimethyl sulfoxide.

[0061] In a preferred embodiment, the second organic solvent is selected from at least one of tetrahydrofuran, acetone, petroleum ether, ethyl acetate, pyridine, methanol, and dichloromethane.

[0062] In step (1) of the present invention, the weight ratio of the first inorganic metal compound and the aromatic organic acid can be 1:0.2-5:5-100.

[0063] In step (1), the reaction temperature can be 100-200℃, for example 100℃, 120℃, 150℃, 180℃ or 200℃; the reaction time can be 5-30 hours, for example 5 hours, 10 hours, 15 hours, 20 hours, 25 hours or 30 hours.

[0064] In a specific embodiment, step (1) specifically includes: reacting a first inorganic metal compound, an aromatic organic acid, an organic acid, and a first organic solvent; allowing the obtained product to stand, separating the solid and liquid phases, washing, and drying to obtain product I. Further, the drying conditions include: a temperature of 50-150°C and a time of 30-120 minutes. Preferably, the drying process can be carried out in a vacuum oven.

[0065] In step (1), the reaction product can be washed with an organic solvent commonly used in the art. Preferably, a first organic solvent can be used for washing.

[0066] Under preferred conditions, in step (2), the weight ratio of product I and the second inorganic metal compound can be 0.5-4:1.

[0067] In step (2), the mixing is carried out at room temperature. Specifically, in step (2), the mixing temperature can be 20-35°C, and the mixing time can be 5-24 hours, for example, 5 hours, 10 hours, 15 hours, 20 hours, or 24 hours. Further, the mixing in step (2) is carried out under stirring conditions.

[0068] In a specific embodiment, step (2) specifically includes: dissolving product I in a second organic solvent, then adding a second inorganic metal compound and mixing; separating the solid and liquid phases of the obtained product, washing, and drying to obtain product II. Further, the drying conditions include: a temperature of 50-150°C and a time of 30-120 minutes. Preferably, the drying process can be carried out in a vacuum oven.

[0069] In step (2), the reaction product can be washed with an organic solvent commonly used in the art. Preferably, a second organic solvent can be used for washing.

[0070] In the method described in this invention, the organometallic compound can be a conventional choice in the art. In a preferred embodiment, the organometallic compound is selected from at least one of ethyl zinc, butyl zinc, methyl zinc, dibutyl zinc, and zinc butadiene.

[0071] In a preferred embodiment, in step (3), the weight ratio of product II to organometallic compound can be 0.5-5:1.

[0072] In step (3), the mixing is carried out at room temperature. Specifically, in step (3), the mixing temperature can be 20-35°C, and the mixing time can be 0.5-10 hours, for example, 0.5 hours, 1 hour, 2 hours, 5 hours, 6 hours, 8 hours, or 10 hours. Further, the mixing in step (3) is carried out under stirring conditions.

[0073] In a specific embodiment, step (3) specifically includes: dissolving product II in a second organic solvent, then adding an organometallic compound and mixing; separating the solid and liquid phases of the obtained product, washing, and drying to obtain product III. Further, the drying conditions include: a temperature of 50-150°C and a time of 30-120 minutes. Preferably, the drying process can be carried out in a vacuum oven.

[0074] In step (3), the reaction product can be washed with an organic solvent commonly used in the art. Preferably, a second organic solvent can be used for washing.

[0075] In a preferred embodiment, the Lewis acid compound is selected from at least one of ferric chloride, aluminum chloride, boron trifluoride, niobium pentachloride, and trifluoromethanesulfonate.

[0076] Under preferred conditions, in step (4), the weight ratio of product III, Lewis acid compound and modifier can be 1:0.5-4:0.5-10.

[0077] The purpose of step (4) of this invention is to introduce alkyl long-chain groups onto the metal-organic framework material (support) synthesized in the aforementioned steps, modify the hydrophobic properties of the catalyst support surface, which can inhibit the adsorption of water molecules, improve the stability of the modified metal-organic framework material as a catalyst for the hydrogenation of carbon dioxide to methanol, and thus improve the selectivity of methanol.

[0078] In this invention, the haloalkane, the alcohol, and the olefin all serve to introduce alkyl groups onto the metal-organic framework material.

[0079] In a specific embodiment, the alkyl group of the haloalkane is a straight-chain and / or branched alkyl group with 2-12 carbon atoms, and the halogen is at least one of Cl, F, I and Br.

[0080] In a preferred embodiment, the haloalkane is selected from at least one of 1-chlorobutane, chloroisooctane, 1-chloropropane, chlorocyclopentane, 1-chlorooctane, and 1-chlorononane.

[0081] In this invention, the alcohol is an alkyl alcohol. Specifically, the alcohol is selected from at least one alkyl alcohol having 2-12 carbon atoms.

[0082] In a preferred embodiment, the alcohol is selected from at least one of propanol, n-butanol, n-pentanol, n-heptanol, and n-octanol.

[0083] In a specific embodiment, the olefin has 2-12 carbon atoms. In a preferred embodiment, the olefin is selected from at least one of propylene, butene, pentene, heptenene, and octene.

[0084] In step (4) of the present invention, the reaction temperature can be 5-100℃, preferably 5-50℃; the reaction time is 0.2-2 hours.

[0085] Step (4) specifically includes: dissolving product III and Lewis acid compound in a second organic solvent, then adding a modifier to react, and performing solid-liquid separation, washing, and drying on the obtained product to obtain a modified metal-organic framework material.

[0086] A second aspect of the present invention provides a modified metal-organic framework material prepared by the method described above.

[0087] A third aspect of the present invention provides the application of the modified metal-organic framework material described above as a catalyst for the hydrogenation of carbon dioxide to methanol.

[0088] In this invention, a "hydrogenation fixed-bed continuous flow reactor-GC combined system" was selected to evaluate the catalytic performance of modified metal-organic framework materials in methanol production.

[0089] The specific method includes: filling a stainless steel reaction tube with 20-40 mesh quartz sand, positioning it at the bottom of the constant temperature zone; adding 1g of the prepared modified metal-organic framework material as a catalyst to the constant temperature zone; continuing to fill the tube with quartz sand; and securing the top with glass wool. The reaction tube is then placed in a heating furnace and connected to the gas path. First, H2 and N2 are introduced in a set ratio, with an H2 volume concentration of 5%-15%. The reaction is carried out for 30-600 minutes at a set reduction temperature of 200-350℃. The temperature is then adjusted to the desired reaction temperature of 200-350℃, and the mixture of CO2, H2, and N2 in a specific ratio is switched to the desired reaction gas, with a CO2 volume concentration of 15%-30% and an H2 volume concentration of 50%-79%. The reaction pressure is then adjusted to the required level of 2-7 MPa. After reacting for 30-360 min, the product gas was sampled and analyzed by passing it through a gas chromatograph that had been running stably. The CO2 conversion rate was calculated by the N2-internal standard method, and the selectivity and yield of methanol were calculated by the C-based internal normalization method.

[0090] Compared with existing technologies, the modified metal-organic framework materials prepared by the method described in this invention have higher methanol selectivity and CO2 conversion rate, with methanol selectivity greater than 95% and CO2 conversion rate greater than 25%.

[0091] The present invention will be described in detail below through embodiments, but the scope of protection of the present invention is not limited thereto.

[0092] Unless otherwise specified, all reagents used in the following examples and comparative examples are common commercial products.

[0093] Example 1

[0094] (1) Dissolve 0.2 g of zirconium chloride, 0.3 g of 4,4'-biphenyl dicarboxylic acid and 10 g of formic acid in 100 mL of N,N-dimethylformamide. Heat to 100 °C and react for 5 hours. After the reaction is complete, let the product stand and centrifuge to obtain a solid product. Wash with N,N-dimethylformamide and put the solid product into a vacuum oven and dry at 80 °C for 120 min to obtain product I.

[0095] (2) Dissolve 0.4g of product I in 100mL of tetrahydrofuran, add 0.2g of copper chloride, stir and dissolve for 5 hours, centrifuge to separate the solid product, wash with the organic solvent tetrahydrofuran, put the solid product into a vacuum oven and dry at 80℃ for 30min to obtain product II.

[0096] (3) Dissolve 0.3g of product II in 100mL of tetrahydrofuran, add 0.1g of ethyl zinc, stir the mixture at room temperature for 0.5 hours, centrifuge to separate the solid product, wash with the organic solvent tetrahydrofuran, put the solid product into a vacuum oven and dry at 100℃ for 30min to obtain product III;

[0097] (4) Dissolve 0.3g of product III and 0.5g of anhydrous aluminum trichloride in 50ml of tetrahydrofuran, add 1.5g of chloroisooctane, stir the mixture at 10℃ for 0.2 hours, centrifuge to separate the solid product, wash with tetrahydrofuran, put the solid product into a vacuum oven and dry at 80℃ for 30min to obtain product IV.

[0098] The catalytic performance of product IV in the production of methanol was evaluated using a combined hydrogenation fixed-bed continuous flow reactor-GC system. A suitable amount of 20-40 mesh quartz sand was packed into a stainless steel reaction tube, positioned at the bottom of the isothermal zone. 1g of product IV was added to the isothermal zone, and the tube was further filled with quartz sand. The top was secured with glass wool. The reaction tube was then placed in a heating furnace, and the gas path was connected, introducing H2 and N2 (H2 volume concentration 5%). The reduction reaction was carried out at 300℃ for 60 min. The temperature was then adjusted to 200℃, and the reaction mixture of CO2, H2, and N2 was introduced (CO2 volume concentration 23%, H2 volume concentration 69%, N2 volume concentration 8%). The reaction pressure was adjusted to 3 MPa, and the reaction was allowed to proceed for 30 min. The product gas was then sampled and analyzed using a stable gas chromatograph. The CO2 conversion rate was calculated using the N2-internal standard method, and the selectivity and yield of methanol were calculated using the C-based internal normalization method. The calculated data are shown in Table 1.

[0099] Example 2

[0100] (1) Dissolve 0.3 g of cerium chloride, 0.4 g of 2,2'-bipyridine-5,5'-dicarboxylic acid, and 20 g of acetic acid in 120 mL of N-methylpyrrolidone. Heat to 120 °C and react for 7 hours. After the reaction is complete, let the product stand and centrifuge to obtain a solid product. Wash with N-methylpyrrolidone and place the solid product in a vacuum oven to dry at 100 °C for 100 min to obtain product I.

[0101] (2) Dissolve 0.5g of product I in 120ml of acetone, add 0.4g of aluminum chloride, stir and dissolve for 6 hours, centrifuge to separate the solid product, wash with organic solvent acetone, put the solid product into a vacuum oven and dry at 100℃ for 40min to obtain product II.

[0102] (3) Dissolve 0.5g of product II in 120mL of tetrahydrofuran, add 0.2g of butyl zinc, stir the mixture at room temperature for 1 hour, centrifuge to separate the solid product, wash with the organic solvent tetrahydrofuran, put the solid product into a vacuum oven and dry at 120℃ for 60min to obtain product III;

[0103] (4) Dissolve 0.3g of product III and 0.5g of anhydrous aluminum trichloride in 50mL of tetrahydrofuran, add 1.5g of chloroisooctane, stir the mixture at 10℃ for 0.2 hours, centrifuge to separate the solid product, wash with tetrahydrofuran, put the solid product into a vacuum oven and dry at 80℃ for 30min to obtain product IV.

[0104] The catalytic performance of product IV in the production of methanol was evaluated using a combined hydrogenation fixed-bed continuous flow reactor-GC system. A suitable amount of 20-40 mesh quartz sand was packed into a stainless steel reaction tube, positioned at the bottom of the isothermal zone. 1g of product IV was added to the isothermal zone, and the tube was further filled with quartz sand. The top was secured with glass wool. The reaction tube was then placed in a heating furnace, and the gas path was connected, introducing H2 and N2 (H2 volume concentration 5%). The reduction reaction was carried out at 300℃ for 60 min. The temperature was then adjusted to 200℃, and the reaction mixture of CO2, H2, and N2 was introduced (CO2 volume concentration 23%, H2 volume concentration 69%, N2 volume concentration 8%). The reaction pressure was adjusted to 3 MPa, and the reaction was allowed to proceed for 30 min. The product gas was then sampled and analyzed using a stable gas chromatograph. The CO2 conversion rate was calculated using the N2-internal standard method, and the selectivity and yield of methanol were calculated using the C-based internal normalization method. The calculated data are shown in Table 1.

[0105] Example 3

[0106] (1) Dissolve 0.3g of zirconium fluoride, 0.4g of terphenyl dicarboxylic acid and 30g of propionic acid in 100mL of acetonitrile and heat to 115℃ for 5 hours. After the reaction is complete, let the product stand and centrifuge to obtain a solid product. Wash with acetonitrile and put the solid product into a vacuum oven and dry at 100℃ for 70min to obtain product I.

[0107] (2) Dissolve 0.6g of product I in 125mL of dichloromethane, add 0.5g of magnesium chloride, stir and dissolve for 7 hours, centrifuge to separate the solid product, wash with organic solvent dichloromethane, put the solid product into a vacuum oven and dry at 105℃ for 45min to obtain product II;

[0108] (3) Dissolve 0.6g of product II in 120mL of dichloromethane, add 0.3g of dibutylzinc, stir the mixture at room temperature for 2 hours, centrifuge to separate the solid product, wash with dichloromethane, put the solid product into a vacuum oven and dry at 100℃ for 70min to obtain product III;

[0109] (4) Dissolve 0.5g of product III and 0.6g of ferric chloride in 50mL of tetrahydrofuran, add 1.2g of n-octanol, stir the mixture at 8℃ for 0.5 hours, centrifuge to separate the solid product, wash with tetrahydrofuran, put the solid product into a vacuum oven and dry at 100℃ for 60min to obtain the modified metal-organic framework material.

[0110] The catalytic performance of product IV in the production of methanol was evaluated using a combined hydrogenation fixed-bed continuous flow reactor-GC system. A suitable amount of 20-40 mesh quartz sand was packed into a stainless steel reaction tube, positioned at the bottom of the isothermal zone. 1g of product IV was added to the isothermal zone, and the tube was further filled with quartz sand. The top was secured with glass wool. The reaction tube was then placed in a heating furnace, and the gas path was connected, introducing H2 and N2 (H2 volume concentration 5%). The reduction reaction was carried out at 300℃ for 60 min. The temperature was then adjusted to 200℃, and the reaction mixture of CO2, H2, and N2 was introduced (CO2 volume concentration 23%, H2 volume concentration 69%, N2 volume concentration 8%). The reaction pressure was adjusted to 3 MPa, and the reaction was allowed to proceed for 30 min. The product gas was then sampled and analyzed using a stable gas chromatograph. The CO2 conversion rate was calculated using the N2-internal standard method, and the selectivity and yield of methanol were calculated using the C-based internal normalization method. The calculated data are shown in Table 1.

[0111] Example 4

[0112] (1) Dissolve 0.4 g of zirconium chloride, 0.4 g of pyridine-2,6-dicarboxylic acid and 35 g of butyric acid in 140 mL of N,N-dimethylacetamide. Heat to 120 °C and react for 6 hours. After the reaction is complete, let the product stand and centrifuge to obtain a solid product. Wash with N,N-dimethylacetamide and place the solid product in a vacuum oven. Dry at 120 °C for 30 min to obtain product I.

[0113] (2) Dissolve 0.7g of product I in 80ml of pyridine, add 0.5g of copper nitrate, stir and dissolve for 7 hours, centrifuge to separate the solid product, wash with organic solvent pyridine, put the solid product into a vacuum oven and dry at 120℃ for 50min to obtain product II;

[0114] (3) Dissolve 0.7g of product II in 120ml of pyridine, add 0.3g of methyl zinc, stir the mixture at room temperature for 2 hours, centrifuge to separate the solid product, wash with pyridine, put the solid product into a vacuum oven and dry at 120℃ for 50min to obtain product III;

[0115] (4) Dissolve 0.7g of product III and 0.6g of boron trifluoride in 100ml of tetrahydrofuran, add 1.2g of octene, stir the mixture at 10℃ for 1 hour, centrifuge to separate the solid product, wash with tetrahydrofuran, put the solid product into a vacuum oven and dry at 110℃ for 60min to obtain product IV.

[0116] The catalytic performance of product IV in the production of methanol was evaluated using a combined hydrogenation fixed-bed continuous flow reactor-GC system. A suitable amount of 20-40 mesh quartz sand was packed into a stainless steel reaction tube, positioned at the bottom of the isothermal zone. 1g of product IV was added to the isothermal zone, and the tube was further filled with quartz sand. The top was secured with glass wool. The reaction tube was then placed in a heating furnace, and the gas path was connected, introducing H2 and N2 (H2 volume concentration 5%). The reduction reaction was carried out at 300℃ for 60 min. The temperature was then adjusted to 200℃, and the reaction mixture of CO2, H2, and N2 was introduced (CO2 volume concentration 23%, H2 volume concentration 69%, N2 volume concentration 8%). The reaction pressure was adjusted to 3 MPa, and the reaction was allowed to proceed for 30 min. The product gas was then sampled and analyzed using a stable gas chromatograph. The CO2 conversion rate was calculated using the N2-internal standard method, and the selectivity and yield of methanol were calculated using the C-based internal normalization method. The calculated data are shown in Table 1.

[0117] Comparative Example 1

[0118] Commercially available copper-based catalyst products (Klein, Germany, MegaMax 800DCARB).

[0119] The catalytic performance of commercially available copper-based catalysts for methanol production was evaluated using a combined hydrogenation fixed-bed continuous flow reactor-GC system. A suitable amount of 20-40 mesh quartz sand was packed into a stainless steel reaction tube, positioned at the bottom of the isothermal zone. 1g of catalyst product IV was added to the isothermal zone, and the tube was further filled with quartz sand. The top was secured with glass wool. The reaction tube was then placed in a heating furnace, and the gas path was connected, introducing H2 and N2 (H2 volume concentration 5%). The reduction reaction was carried out at 300℃ for 60 min. The temperature was then adjusted to 200℃, and the reaction mixture of CO2, H2, and N2 was introduced (CO2 volume concentration 23%, H2 volume concentration 69%, N2 volume concentration 8%). The reaction pressure was adjusted to 3 MPa, and the reaction was allowed to proceed for 30 min. The product gas was then sampled and analyzed using a stable gas chromatograph. The CO2 conversion rate was calculated using the N2-internal standard method, and the selectivity and yield of methanol were calculated using the C-based internal normalization method. The calculated data are shown in Table 1.

[0120] Comparative Example 2

[0121] The method of Example 1 was implemented, except that step (4) was not performed, and product III was obtained.

[0122] The catalytic performance of product III in the production of methanol was evaluated using a combined hydrogenation fixed-bed continuous flow reactor-GC system. A suitable amount of 20-40 mesh quartz sand was packed into a stainless steel reaction tube, positioned at the bottom of the isothermal zone. 1 g of product III was added to the isothermal zone, and the tube was further filled with quartz sand. The top was secured with glass wool. The reaction tube was then placed in a heating furnace, and the gas path was connected, introducing H2 and N2 (H2 volume concentration 5%). The reduction reaction was carried out at 300℃ for 60 min. The temperature was then adjusted to 200℃, and the reaction mixture of CO2, H2, and N2 was introduced (CO2 volume concentration 23%, H2 volume concentration 69%, N2 volume concentration 8%). The reaction pressure was adjusted to 3 MPa, and the reaction was allowed to proceed for 30 min. The product gas was then sampled and analyzed using a stable gas chromatograph. The CO2 conversion rate was calculated using the N2-internal standard method, and the selectivity and yield of methanol were calculated using the C-based internal normalization method. The calculated data are shown in Table 1.

[0123] Table 1 Catalytic performance data of catalysts

[0124] Example number <![CDATA[CO2 conversion rate (%)]]> Methanol selectivity (%) Example 1 28 97 Example 2 28 95 Example 3 27 97 Example 4 28 96 Comparative Example 1 26 55 Comparative Example 2 21 68

[0125] As shown in Table 1, the material prepared using the method described in the embodiments of the present invention exhibits higher methanol selectivity and CO2 conversion rate. The methanol selectivity is greater than 95%, and the CO2 conversion rate is greater than 25%.

[0126] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing modified metal-organic framework materials, characterized in that, The method includes the following steps: (1) The first inorganic metal compound, the aromatic organic acid, the organic acid and the first organic solvent are reacted and separated into solid and liquid components to obtain product I, wherein the aromatic organic acid is selected from at least one of 4,4'-biphenyl dicarboxylic acid, 2,2'-bipyridine-5,5'-dicarboxylic acid, triphenyl dicarboxylic acid, pyridine-2,6-dicarboxylic acid and 2,3-pyridine-dicarboxylic acid, and the organic acid is selected from at least one of formic acid, acetic acid, propionic acid, butyric acid, octanoic acid, adipic acid, oxalic acid, malonic acid, succinic acid, maleic acid, tartaric acid, benzoic acid, phenylacetic acid, phthalic acid, terephthalic acid, valeric acid, hexanoic acid, decanoic acid and stearic acid; (2) Mix product I, the second organic solvent, and the second inorganic metal compound, and separate the solid and liquid phases to obtain product II; (3) Mix product II, the second organic solvent and the organometallic compound, and separate the solid and liquid phases to obtain product III; (4) The product III, Lewis acid compound, second organic solvent and modifier are reacted to obtain modified metal-organic framework material; Wherein, the first inorganic metal compound and the second inorganic metal compound are different, and the modifier is selected from at least one of haloalkanes, alcohols and alkenes; In the haloalkane, the alkyl group is a straight-chain and / or branched alkyl group having 2-12 carbon atoms, and the halogen is at least one of Cl, F, I and Br; The alcohol is selected from at least one of alkyl alcohols having 2-12 carbon atoms in the alkyl group; In the olefins, the number of carbon atoms is 2-12.

2. The method according to claim 1, characterized in that, Both the first inorganic metal compound and the second inorganic metal compound are selected from at least one of zirconium chloride, zirconium fluoride, zirconium oxychloride octahydrate, cerium nitrate, cerium nitrate hexahydrate, cerium chloride, cobalt nitrate, nickel nitrate hexahydrate, nickel nitrate, nickel chloride hexahydrate, cobalt nitrate hexahydrate, ytterbium chloride, ferrous chloride tetrahydrate, tin chloride pentahydrate, copper chloride, copper sulfate, copper nitrate, cuprous oxide, cuprous chloride, aluminum chloride, and magnesium chloride.

3. The method according to claim 2, characterized in that, The first inorganic metal compound is selected from at least one of zirconium chloride, zirconium fluoride, zirconium oxychloride octahydrate, cerium nitrate, cerium nitrate hexahydrate, cerium chloride, cobalt nitrate, nickel nitrate hexahydrate, nickel nitrate, nickel chloride hexahydrate, cobalt nitrate hexahydrate, ytterbium chloride, ferrous chloride tetrahydrate, and tin chloride pentahydrate.

4. The method according to claim 2, characterized in that, The second inorganic metal compound is selected from at least one of copper chloride, copper sulfate, copper nitrate, cuprous oxide, cuprous chloride, aluminum chloride, and magnesium chloride.

5. The method according to claim 1 or 2, characterized in that, The organic acid is selected from at least one of formic acid, acetic acid, propionic acid, and oxalic acid.

6. The method according to claim 1, characterized in that, The first organic solvent is selected from at least one of N,N-dimethylformamide, N-methylpyrrolidone, acetonitrile, acetone, butanone, N,N-dimethylacetamide, and dimethyl sulfoxide.

7. The method according to claim 1, characterized in that, The second organic solvent is selected from at least one of tetrahydrofuran, acetone, petroleum ether, ethyl acetate, pyridine, methanol, and dichloromethane.

8. The method according to claim 1 or 2, characterized in that, The organometallic compound is selected from at least one of ethyl zinc, butyl zinc, methyl zinc, dibutyl zinc, and zinc butadiene.

9. The method according to claim 1, characterized in that, The Lewis acid compound is selected from at least one of ferric chloride, aluminum chloride, boron trifluoride, niobium pentachloride, and trifluoromethanesulfonate.

10. The method according to claim 1, characterized in that, The haloalkane is selected from at least one of 1-chlorobutane, chloroisooctane, 1-chloropropane, chlorocyclopentane, 1-chlorooctane, and 1-chlorononane.

11. The method according to claim 1, characterized in that, The alcohol is selected from at least one of propanol, n-butanol, n-pentanol, n-heptanol, and n-octanol.

12. The method according to claim 1, characterized in that, The olefin is selected from at least one of propylene, butene, pentene, heptenene, and octene.

13. The method according to claim 1 or 2, characterized in that, In step (1), the weight ratio of the first inorganic metal compound, the aromatic organic acid and the organic acid is 1:0.2-5:5-200.

14. The method according to claim 1 or 2, characterized in that, In step (1), the reaction conditions include a temperature of 100-200°C and a time of 5-30 hours.

15. The method according to claim 1, characterized in that, In step (2), the weight ratio of product I and the second inorganic metal compound is 0.5-4:

1.

16. The method according to claim 1, characterized in that, In step (2), the mixing conditions include a temperature of 20-35°C and a time of 5-24 hours.

17. The method according to claim 1, characterized in that, In step (3), the weight ratio of product II to organometallic compound is 0.5-5:

1.

18. The method according to claim 1, characterized in that, In step (3), the mixing conditions include a temperature of 20-35°C and a time of 0.5-10 hours.

19. The method according to claim 1, characterized in that, In step (4), the weight ratio of product III, Lewis acid compound and modifier is 1:0.5-4:0.5-10.

20. The method according to claim 1, characterized in that, In step (4), the reaction conditions include a temperature of 5-100℃ and a time of 0.2-2 hours.

21. A modified metal-organic framework material prepared by the method according to any one of claims 1-20.

22. The use of the modified metal-organic framework material of claim 21 as a catalyst for the hydrogenation of carbon dioxide to methanol.