Supported catalyst as well as preparation method and application thereof

Abstract

The invention provides a supported catalyst and a preparation method and application thereof, the supported catalyst comprises a carrier and an active component, the active component comprises Pd, and the carrier is MIL-101 (13% Cr) modified by a nitrogen heterocyclic compound; the nitrogen heterocyclic compound is a nitrogen heterocyclic ligand. The supported catalyst has the beneficial effects that the supported catalyst has a unique crystalline structure and a unified reaction microenvironment, is used for preparing benzyl alcohol through benzaldehyde hydrogenation, and is high in active site utilization rate, high in catalytic efficiency and high in benzyl alcohol selectivity.

Description

Technical Field

[0001] The invention belongs to the technical field of metal supported catalyst preparation, and specifically relates to a supported catalyst and a preparation method and application thereof. Background Art

[0002] Benzyl alcohol, also known as benzyl alcohol, is one of the simplest aromatic alcohols. As a solvent, plasticizer, and preservative, benzyl alcohol is also widely used in the fragrance, soap, medicine, dye and other industries. In addition, in recent years, the application of benzyl alcohol in the pharmaceutical, consumer electronics, additive materials and home decoration industries has continued to increase, which has promoted the rapid development of my country's benzyl alcohol industry, and the industry's production and sales scale have both increased.

[0003] At present, the preparation methods of benzyl alcohol mainly include benzyl chloride hydrolysis method; toluene oxidation method; benzaldehyde liquid phase hydrogenation method, etc. Benzyl chloride hydrolysis method is the main industrialized method at home and abroad, and can be further divided into intermittent method and continuous method. The intermittent method has a low conversion rate, while the continuous method has harsh reaction conditions. The toluene oxidation method has a low conversion rate and produces many by-products. The preparation of benzyl alcohol by liquid phase hydrogenation of benzaldehyde is a simple production process technology with mild reaction conditions and environmental friendliness. Supported palladium catalysts have a high conversion rate and are ideal hydrogenation catalysts, but are easily affected by the surface properties of the carrier and are prone to secondary reactions to produce toluene and phenylethyl ether by-products. Improving the selectivity of benzyl alcohol at high conversion rates is a key issue that needs to be solved in this reaction system. Summary of the invention

[0004] To solve the above problems, the present application provides a catalyst capable of improving the product selectivity of preparing benzyl alcohol by liquid phase hydrogenation of benzaldehyde at a high conversion rate, as well as a preparation method and application thereof.

[0005] In a first aspect of the present invention, a supported catalyst is provided, comprising a carrier and an active component, wherein the active component comprises Pd, and the carrier is MIL-101 (13% Cr) modified with a nitrogen heterocyclic compound.

[0006] The nitrogen heterocyclic compound modified MIL-101 (13% Cr) in the catalyst can be obtained by the following method:

[0007] Method 1: Before impregnation with palladium, MIL-101 (13% Cr) is modified with a nitrogen heterocyclic compound to obtain MIL-101 (13% Cr) modified with a nitrogen heterocyclic compound, and then palladium is impregnated with the MIL-101 (13% Cr) modified with the nitrogen heterocyclic compound, and other subsequent steps;

[0008] Method 2: Add nitrogen heterocyclic compounds to the palladium impregnation solution. When MIL-101 (13% Cr) contacts the palladium impregnation solution, the nitrogen heterocyclic compounds in the impregnation solution coordinate with MIL-101 (13% Cr) to form nitrogen heterocyclic compound-modified MIL-101 (13% Cr).

[0009] According to some implementation cases of the catalyst described in the present application, based on the total mass of the catalyst, the mass percentage of Pd is 0.1%-10% (for example: 0.1%, 0.2%, 0.5%, 1.0%, 1.2%, 1.5%, 2%, 2.5%, 2.8%, 3.0%, 3.2%, 3.6%, 3.8%, 5%, 5.5%, 6.2%, 7.0%, 7.6%, 8.0%, 8.2%, 9%, 10%), preferably 0.1%-5%, further preferably 0.2-2%, more preferably 0.3%-1.5%, most preferably 0.5%-1%;

[0010] According to some implementation cases of the catalyst described in the present application, the nitrogen heterocyclic compound is at least one of pyridine, imidazole, and 4,4'-bipyridine.

[0011] The second aspect of the present invention provides a method for preparing a Pd@MIL-101 catalyst, comprising the following steps:

[0012] (1) Preparation of palladium colloid solution:

[0013] The palladium-containing compound, organic acid, anionic surfactant, nitrogen heterocyclic compound and water are mixed to obtain palladium colloid;

[0014] (2) contacting the palladium colloid with the activated MIL-101 (13% Cr), aging and reducing the resulting product, and performing solid-liquid separation and drying to obtain a supported catalyst.

[0015] According to some embodiments of the preparation method described in the present application, in step (1), the pH value of the palladium colloid solution is 4.0-7.0 (such as pH value 4.2, pH value 5.2, pH value 6.1, pH value 7.0), preferably 4.0-6.0.

[0016] According to some embodiments of the preparation method described in the present application, the palladium-containing compound is one or more of palladium sulfate, chloropalladic acid or palladium phosphate.

[0017] According to some embodiments of the preparation method described in the present application, the organic acid is at least one of tartaric acid, glacial acetic acid, and citric acid.

[0018] According to some embodiments of the preparation method described in the present application, the anionic surfactant is potassium dodecyl polyoxyethylene ether phosphate or sodium hexadecylbenzene sulfonate.

[0019] According to some embodiments of the preparation method described in the present application, the nitrogen heterocyclic compound is at least one of pyridine, imidazole, and 4,4'-bipyridine.

[0020] According to some embodiments of the preparation method described in the present application, the weight ratio of the palladium-containing compound, organic acid, nitrogen heterocyclic compound, anionic surfactant, and water is 0.0015-0.15: 0.005-0.02: 0.005-0.02: 0.001-0.01, preferably 0.0050-0.10: 0.008-0.012: 0.010-0.015: 0.005-0.008.

[0021] According to some embodiments of the preparation method described in the present application, in step (1), the pH value of the palladium colloid solution is adjusted using a sodium carbonate solution with a mass percentage of 5%-15% (for example: 5%, 8%, 10%, 12%, 15%), preferably 8%-12%.

[0022] According to some embodiments of the preparation method described in the present application, in step (2), the method for activating MIL-101 (13% Cr) is: washing MIL-101 (13% Cr) with a replacement liquid and a solution, separating the solid and the liquid, and drying to obtain activated MIL-101 (13% Cr).

[0023] According to some embodiments of the preparation method described in the present application, the replacement fluid is one of N,N'-dimethylformamide and N,N'-dimethylacetamide.

[0024] According to some embodiments of the preparation method described in the present application, the solution is a mixed solution of acetone and ethanol.

[0025] According to some embodiments of the preparation method described in the present application, the drying is one of high-temperature vacuum drying or inert atmosphere drying. Preferably, the temperature of the high-temperature vacuum drying is 120°C-200°C (for example: 120°C, 130°C, 150°C, 160°C, 180°C, 200°C), and the vacuum degree is 0.5-0.9 bar.

[0026] According to some embodiments of the preparation method described in the present application, the drying is drying in a nitrogen atmosphere.

[0027] According to some embodiments of the preparation method described in the present application, in step (2), the mass ratio of the palladium colloid solution to the activated MIL-101 (13% Cr) is 10:1-7 (for example: 10:1, 10:2, 10:3, 10:4, 10:5, 10:6, 10:7), preferably 10:3-6.

[0028] According to some embodiments of the preparation method described in the present application, the aging is: aging at 15-30°C (such as 15°C, 18°C, 20°C, 25°C, 28°C, 30°C) for 20-30h (such as 20h, 22h, 25h, 28h, 30h).

[0029] According to some embodiments of the preparation method described in the present application, the reducing agent used for the reduction is selected from one or more of sodium oxalate solution, sodium sulfite solution, sodium formate solution, formic acid solution, and sodium nitrite solution.

[0030] According to some embodiments of the preparation method described in the present application, the reducing agent is a sodium formate solution with a mass fraction of 5-10%.

[0031] According to some embodiments of the preparation method described in the present application, the mass ratio of the added amount of the reducing agent to the activated MIL-101 (13% Cr) is 0.5-2:1 (for example: 0.5:1, 0.8:1, 1:1, 1.5:1, 2:1), preferably 0.8-1.5:1.

[0032] According to some embodiments of the preparation method described in the present application, the reduction reaction conditions are: reduction treatment for 30-90 min (for example: 30 min, 40 min, 45 min, 50 min, 55 min, 60 min, 65 min, 70 min, 80 min, 90 min, 100 ° C, 105 ° C, 110 ° C, 112 ° C, 120 ° C, 125 ° C, 128 ° C, 130 ° C, 135 ° C, 136 ° C, 138 ° C, 140 ° C, 150 ° C) under the conditions of 50-150 ° C (for example: 50 ° C, 55 ° C, 60 min, 68 ° C, 76 ° C, 80 ° C, 85 ° C, 88 ° C, 90 ° C, 100 ° C, 105 ° C, 110 ° C, 112 ° C, 120 ° C, 125 ° C, 128 ° C, 130 ° C, 135 ° C, 136 ° C, 138 ° C, 140 ° C, 150 ° C).

[0033] According to some embodiments of the preparation method described in the present application, the drying is: drying at a temperature of 100-200° C. for 10-30 hours.

[0034] The third aspect of the present invention provides the use of the catalyst described in the first aspect of the present invention or the catalyst obtained by the preparation method described in the second aspect of the present invention in the preparation of benzyl alcohol by hydrogenation of benzaldehyde.

[0035] In a fourth aspect of the present invention, a method for preparing benzyl alcohol by hydrogenating benzaldehyde is provided, wherein benzyl alcohol is obtained by hydrogenating benzaldehyde with hydrogen in the presence of the catalyst described in the first aspect of the present invention or the catalyst obtained by the preparation method described in the second aspect of the present invention.

[0036] According to some embodiments of the method for preparing benzyl alcohol by hydrogenating benzaldehyde of the present invention, the solvent of the hydrogenation reaction is ethanol, isopropanol or n-butanol, preferably ethanol.

[0037] According to some embodiments of the method for preparing benzyl alcohol by hydrogenating benzaldehyde of the present invention, the temperature of the hydrogenation reaction is 20-100°C (for example: 20°C, 30°C, 35°C, 38°C, 40°C, 45°C, 50°C, 55°C, 58°C, 60°C, 65°C, 68°C, 70°C, 75°C, 78°C, 80°C, 85°C, 90°C, 95°C, 100°C).

[0038] According to some embodiments of the method for preparing benzyl alcohol by hydrogenating benzaldehyde of the present invention, the pressure of the hydrogenation reaction is 0.1-1.0 MPa (0.1 MPa, 0.2 MPa, 0.3 MPa, 0.6 MPa, 0.8 MPa, 0.9 MPa, 1 MPa,).

[0039] Compared with the prior art, the beneficial effects of the present invention are as follows: the supported catalyst of the present invention has a unique crystalline structure and a unified reaction microenvironment, and is used in the preparation of benzyl alcohol by hydrogenation of benzaldehyde, and the active site utilization rate of the catalyst is high, the catalytic efficiency is high, and the selectivity for benzyl alcohol is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is the microscopic morphology of the synthesized catalyst 1% Pd@MIL-101 (13% Cr) described in Example 2.

[0041] Figure 2 This is the PXRD spectrum of the synthesized catalyst 1% Pd@MIL-101 (13% Cr) described in Example 2. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the embodiments and drawings. The specific embodiments described herein are only used to explain the present invention and are not intended to constitute any limitation to the present invention. In addition, in the following description, the description of known structures and technologies is omitted to avoid unnecessary confusion of the concepts of the present disclosure. Such structures and technologies are also described in many publications.

[0043] The synthesis of the carrier MIL-101 (13% Cr) is based on the preparation method described in the literature Férey, G.; Mellot-Draznieks, C.; Serre, C., et al. A chromium terephthalate-based solid with unusually large pore volumes and surface area [J]. Science, 2005, 309: 2040-2042. MIL-101 (13% Cr) is a crystalline porous material with three-dimensional pores and good thermal and chemical stability.

[0044] Solution washing and drying activation method of MIL-101 (13% Cr): Add 5 equivalents of DMF to MIL-101 (13% Cr), stir at 80°C for 4 hours, and filter to collect the solid. Wash with a mixed liquid of ethanol and acetone at 70°C for 4 hours, filter to collect the solid, and dry at 120°C for 24 hours to obtain the activated MIL-101 (13% Cr).

[0045] Catalyst activity evaluation conditions:

[0046] Sample loading and evaluation in autoclave;

[0047] Catalyst dosage: The amount of catalyst added is determined by adding 1 mg of palladium;

[0048] Reactant benzaldehyde: 10.00g;

[0049] Solvent: ethanol, 100.00 g;

[0050] Hydrogen pressure: 0.5MPa;

[0051] Reaction temperature: 50°C;

[0052] After 1 hour, samples were taken and analyzed by gas chromatography;

[0053]

[0054]

[0055] The present invention will be further described below by way of examples.

[0056] Example 1

[0057] Weigh 20g of dried activated MIL-101 (13% Cr). Weigh 0.5g of chloropalladic acid aqueous solution (20% palladium mass fraction), add 5.0g of deionized water, then add 0.05g of tartaric acid, 0.05g of glacial acetic acid, 0.10g of pyridine, 0.02g of potassium dodecyl polyoxyethylene ether phosphate and 0.10g of citric acid, adjust the pH to 5.1 with 10% sodium carbonate solution, and add deionized water to 14.0g to obtain palladium colloid.

[0058] In a rotating pot, the palladium colloid was sprayed into the activated MIL-101 (13% Cr) carrier. After sufficient impregnation, the solid was placed in a beaker and aged at room temperature for 24 hours. 200g of a 2% sodium formate aqueous solution was added and reduced at 100°C for 1 hour. The catalyst product 0.5% Pd@MIL-101 (13% Cr) was obtained by washing, filtering, and drying at 150°C.

[0059] Example 2

[0060] The amount of chloropalladic acid aqueous solution (20% palladium by mass) added in Example 1 was changed to 1 g, and other conditions remained unchanged to synthesize the catalyst product 1% Pd@MIL-101 (13% Cr).

[0061] Example 3

[0062] The amount of chloropalladic acid aqueous solution (20% palladium mass fraction) added in Example 1 was changed to 2 g, and other conditions remained unchanged to synthesize the catalyst product 2% Pd@MIL-101 (13% Cr).

[0063] Example 4

[0064] The amount of chloropalladic acid aqueous solution (20% palladium by mass) added in Example 1 was changed to 4 g, and other conditions remained unchanged to synthesize the catalyst product 4% Pd@MIL-101 (13% Cr).

[0065] Example 5

[0066] The amount of chloropalladic acid aqueous solution (20% palladium by mass) added in Example 1 was changed to 5 g, and other conditions remained unchanged to synthesize the catalyst product 5% Pd@MIL-101 (13% Cr).

[0067] Comparative Example 1

[0068] Weigh 20g of activated carbon for later use. Weigh 1.0g of chloropalladic acid aqueous solution (20% palladium mass fraction), add 5g of deionized water, then add 0.05g of tartaric acid, 0.05g of glacial acetic acid, 0.02g of potassium dodecyl polyoxyethylene ether phosphate and 0.10g of citric acid, adjust the pH to 5.1 with 10% sodium carbonate solution, add deionized water to 10.0g to obtain palladium colloid. Spray the palladium colloid into the activated carbon carrier in a rotating pot. After sufficient impregnation, place the solid in a beaker and age at room temperature for 24h, add 200g of 2% sodium formate aqueous solution by mass, and reduce at 100℃ for 1h. Wash, filter, and dry at 150℃ to obtain the catalyst product 1%Pd@Carbon.

[0069] Comparative Example 2

[0070] The metal-organic framework Cu was synthesized according to the literature Chui, SS, et al., A chemically functionalizable nanoporous material. Science, 1999. 283(5405): p.1148-50. 3 (BTC) 2 (H 2 O) 3 (also known as HKUST-1), in which the Cu content is 19wt%.

[0071] Weigh 20g HKUST-1. Weigh 1.0g chloropalladic acid aqueous solution (20% palladium mass fraction), add 4.0g deionized water, then add 0.05g tartaric acid, 0.05g glacial acetic acid, 0.02g potassium dodecyl polyoxyethylene ether phosphate and 0.10g citric acid, adjust the pH to 5.1 with 10% sodium carbonate solution, add deionized water to 6.6g to obtain palladium colloid. Spray the palladium colloid into the HKUST-1 carrier in a rotating pot, and after sufficient impregnation, place the solid in a beaker and age at room temperature for 24h, add 200g of 2% sodium formate aqueous solution, and reduce at 100℃ for 1h. Wash, filter, and dry at 150℃ to obtain the catalyst product 1%Pd@HKUST-1(19%Cu).

[0072] Comparative Example 3

[0073] According to the literature Cavka, JH; Jakobsen, S.; Olsbye, U., et al. A new zirconiuminorganic building brick forming metal organic frameworks with exceptional stability [J]. J.Am.Chem.Soc., 2008, 130: 13850-13851, a metal-organic framework Zr24O120C192H96 (also known as UIO-66) was synthesized, in which the Zr content was 33 wt%.

[0074] The metal-organic framework support (Comparative Example 2) was replaced with UIO-66 to synthesize a catalyst 1% Pd@UIO-66 (33% Zr).

[0075] Comparative Example 4

[0076] According to the literature Cavka, JH; Jakobsen, S.; Olsbye, U., et al. A new zirconiuminorganic building brick forming metal organic frameworks with exceptional stability [J]. J.Am.Chem.Soc., 2008, 130: 13850-13851. a metal-organic framework C84H8O32Zr6 (also known as UIO-67) was synthesized, in which the Zr content was 23 wt%.

[0077] The metal-organic framework support (Comparative Example 2) was replaced with UIO-67 to synthesize a catalyst 1% Pd@UIO-67 (23% Zr).

[0078] Comparative Example 5

[0079] According to the literature Férey, G.; Serre, C.; Mellot-Draznieks, C., et al. A hybrid solid with giant pores prepared by a combination of targeted chemistry, simulation, and powder diffraction [J]. Angew. Chem. Int. Ed., 2004, 43: 6296-6301. Synthesis of metal-organic framework Cr 3 F(H 2 O) 3 O[C 6 H 3 -(CO 2 ) 3 ] 2 .28H 2 O (also known as MIL-100 (Cr)), in which the Cr content is 17wt%.

[0080] The metal-organic framework support (Comparative Example 2) was replaced with MIL-100 (Cr) to synthesize a catalyst 1% Pd@MIL-100 (17% Cr).

[0081] Comparative Example 6

[0082] Weigh 20g of dried activated MIL-101 (13% Cr). Weigh 1.0g of chloropalladic acid aqueous solution (20% palladium mass fraction), add 5.0g of deionized water, then add 0.05g of tartaric acid, 0.05g of glacial acetic acid, 0.02g of potassium dodecyl polyoxyethylene ether phosphate and 0.10g of citric acid, adjust the pH to 5.1 with 10% sodium carbonate solution, and add deionized water to 14.0g to obtain palladium colloid.

[0083] In a rotating pot, the palladium colloid was sprayed into the activated MIL-101 (13% Cr) carrier. After sufficient impregnation, the solid was placed in a beaker and aged at room temperature for 24 hours. 200g of a 2% sodium formate aqueous solution was added and reduced at 100°C for 1 hour. The catalyst product 1% Pd@MIL-101 (13% Cr)-Pyridine free was obtained by washing, filtering, and drying at 150°C.

[0084] The contents of the metal element components of the catalysts in the examples and comparative examples and the benzaldehyde hydrogenation evaluation results of the catalysts using the above-mentioned activity evaluation conditions are shown in Table 1.

[0085] Table 1

[0086] sample Palladium content (wt%) Second metal and content (wt%) Benzaldehyde conversion rate Benzyl alcohol selectivity Example 1 0.5％ 13％Cr 99.1％ 99.3％ Example 2 1％ 13％Cr 99.9％ 99.8％ Example 3 2％ 13％Cr 92.3％ 95.3％ Example 4 4％ 13％Cr 85.7％ 96.0％ Example 5 5％ 13％Cr 74.9％ 91.2％ Comparative Example 1 1％ / 31.2％ 51.3％ Comparative Example 2 1％ 19%Cu 51.8％ 63.1％ Comparative Example 3 1％ 33％Zr 37.4％ 57.2％ Comparative Example 4 1％ 23％Zr 43.2％ 52.9％ Comparative Example 5 1％ 17％Cr 55.3％ 48.3％ Comparative Example 6 1％ 13％Cr 25.6％ 51.8％

[0087] It can be seen from Table 1 that the supported palladium catalysts prepared in the embodiments and comparative examples of the present invention, which are prepared by impregnating and reducing MIL-101 (13% Cr) as a carrier with equal volumes of palladium colloid, have a unique pore structure and a high utilization rate of metal active sites, and can significantly improve the conversion rate of benzaldehyde and the selectivity of the product benzyl alcohol. Among them, the 1% Pd@MIL-101 (13% Cr) catalyst in Example 2 with a palladium mass percentage of 1% has the best conversion rate and selectivity.

[0088] 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 supported catalyst, comprising a carrier and an active component, wherein the active component comprises Pd, and the carrier is MIL-101 (13% Cr) modified with a nitrogen heterocyclic compound.

2. The supported catalyst according to claim 1, characterized in that Based on the total mass of the catalyst, the mass percentage of Pd is 0.1%-10%, preferably 0.1%-5%, further preferably 0.2-2%, more preferably 0.3%-1.5%, most preferably 0.5%-1%; and / or The nitrogen heterocyclic compound is at least one of pyridine, imidazole and 4,4'-bipyridine, and preferably the nitrogen heterocyclic compound is pyridine.

3. A method for preparing a supported catalyst, comprising the following steps: (1) mixing a palladium-containing compound, an organic acid, an anionic surfactant, a nitrogen heterocyclic compound and water to obtain a palladium colloid; (2) contacting the palladium colloid with the activated MIL-101 (13% Cr), aging and reducing the reduced product, separating the solid from the liquid, and drying to obtain a supported catalyst.

4. The preparation method according to claim 3, characterized in that: In step (1), the pH value of the palladium colloid solution is 4.0-7.0, preferably 4-6. Preferably, the palladium-containing compound is one or more of palladium sulfate, chloropalladic acid or palladium phosphate; And / or, the organic acid is at least one of tartaric acid, acetic acid, and citric acid; And / or, the anionic surfactant is potassium dodecyl polyoxyethylene ether phosphate or sodium hexadecylbenzene sulfonate; And / or, the nitrogen heterocyclic compound is at least one of pyridine, imidazole and 4,4'-bipyridine.

5. The preparation method according to claim 3 or 4, characterized in that: The weight ratio of the palladium-containing compound, the organic acid, the nitrogen heterocyclic compound, the anionic surfactant and water is 0.0015-0.15: 0.005-0.02: 0.005-0.02: 0.001-0.01, preferably 0.0050-0.10: 0.008-0.012: 0.010-0.015: 0.005-0.

008.

6. The preparation method according to any one of claims 4 to 5, characterized in that: In step (1), the pH value of the palladium colloid solution is adjusted by using a sodium carbonate solution with a mass percentage of 5%-15%, preferably 8%-12%.

7. The preparation method according to any one of claims 3 to 5, characterized in that: In step (2), the method for activating MIL-101 (13% Cr) is as follows: washing MIL-101 (13% Cr) with a replacement liquid and a solution, separating the solid from the liquid, and drying to obtain activated MIL-101 (13% Cr); Preferably, the replacement fluid is one of N,N'-dimethylformamide and N,N'-dimethylacetamide; And / or, the solution is a mixed solution of acetone and ethanol; And / or, the drying is one of high temperature vacuum drying or inert atmosphere drying. Preferably, the temperature of the high temperature vacuum drying is 120° C.-200° C., and the vacuum degree is 0.5-0.9 bar; Preferably, the drying is drying in a nitrogen atmosphere.

8. The preparation method according to any one of claims 3 to 6, characterized in that: In step (2), the mass ratio of the palladium colloid solution to the activated MIL-101 (13% Cr) is 10:1-7, preferably 10:3-6; And / or, the aging is: aging at 15-30° C. for 20-30 h; And / or, the reducing agent used in the reduction is selected from one or more of sodium oxalate solution, sodium sulfite solution, sodium formate solution, formic acid solution, and sodium nitrite solution. Preferably, the reducing agent is a sodium formate solution with a mass fraction of 5-10%; Preferably, the mass ratio of the amount of the reducing agent added to the activated MIL-101 (13% Cr) is 0.5-2:1, preferably 0.8-1.5:1; And / or, the reduction reaction conditions are: reduction treatment at 50-150° C. for 30-90 min; And / or, the drying is: drying at a temperature of 100-200° C. for 10-30 hours.

9. Use of the catalyst according to any one of claims 1 to 2 or the catalyst obtained by the preparation method according to any one of claims 3 to 8 in the preparation of benzyl alcohol by hydrogenation of benzaldehyde.

10. A method for preparing benzyl alcohol by hydrogenating benzaldehyde, wherein benzyl alcohol is obtained by hydrogenating benzaldehyde with hydrogen in the presence of the catalyst according to any one of claims 1 to 2 or the catalyst obtained by the preparation method according to any one of claims 3 to 8; Preferably, the solvent for the hydrogenation reaction is ethanol, isopropanol or n-butanol, preferably ethanol; And / or, the temperature of the hydrogenation reaction is 20-100°C; And / or, the pressure of the hydrogenation reaction is 0.1-1.0 MPa.

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