Hydrogenation catalyst with molecular imprinting function and preparation method and application thereof

Abstract

The invention discloses a hydrogenation catalyst with a molecular imprinting function and a preparation method and application thereof. The catalyst provided by the invention has selective adsorption on aromatic hydroxylamine compounds, greatly reduces the generation of a by-product tar caused by hydroxylamine condensation reaction in a nitro compound hydrogenation process, can effectively inhibit ring hydrogenation, and reduces the generation of light components. Compared with traditional Raney nickel, noble metal catalysts and common supported nickel catalysts, the catalyst provided by the invention has better selectivity and longer service life.

Description

Technical Field

[0001] The invention belongs to the field of catalysts and relates to a hydrogenation catalyst with molecular imprinting function and a preparation method and application thereof. Background Art

[0002] Toluenediamine (TDA, also known as diaminotoluene) is an important raw material for the production of toluene diisocyanate (TDI), and is widely used in dyes, pharmaceutical intermediates and other organic synthetic intermediates. The toluene diisocyanate prepared from it is one of the important raw materials for the production of polyurethane. How to prepare toluenediamine efficiently and economically is a research hotspot at home and abroad.

[0003] At present, the method of liquid-phase catalytic hydrogenation of dinitrotoluene (DNT) is generally used for preparing toluenediamine in industry, wherein there are mainly two kinds of hydrogenation catalysts used for hydrogenation reaction, namely noble metal system catalysts and nickel catalysts. The main active components of noble metal catalysts are palladium and platinum noble metals, and the reaction conditions of such catalysts are mild and the catalytic activity is high, but the tar byproducts are high, the yield of toluenediamine is low, and the noble metals loaded on the carrier are easy to lose at the same time, and the application cost is relatively high, such as the carbon black catalyst of palladium platinum iron disclosed in CN105435808A; Nickel catalysts are mainly supported nickel catalysts and skeleton nickel catalysts, and the catalytic activity of such catalysts is high and the tar production is low, but such catalysts are due to their high active component density, and the Ni content is generally greater than 50%, and it is easy to form over-hydrogenated products.

[0004] CN112958114A discloses a Raney nickel catalyst for the hydrogenation of aromatic nitro compounds in a fixed bed. The catalyst utilizes the high unsaturation of the active metal surface and the adsorption selectivity of the substrate functional groups on the catalyst surface to solve the problem of controlling azo condensation by-products in the hydrogenation process of aromatic nitro compounds, thereby improving the selectivity of the target aromatic ammonia product and the service life of the catalyst. However, the catalyst has a high loading amount of active components, which inevitably leads to the generation of over-hydrogenation by-products. Summary of the invention

[0005] In order to solve the deficiencies of the prior art, the present invention provides a hydrogenation catalyst and a preparation method and application thereof, wherein the catalyst has selective adsorption to aromatic hydroxylamine compounds, greatly reduces the generation of byproduct tar caused by the hydroxylamine condensation reaction during the hydrogenation of nitro compounds, and can effectively inhibit the ring hydrogenation and reduce the generation of light components. The catalyst of the present invention can catalyze the hydrogenation of dinitrotoluene to prepare toluenediamine with high selectivity.

[0006] In a first aspect, the present invention provides a method for preparing a hydrogenation catalyst having a molecular imprinting function, comprising the following steps:

[0007] S1, placing the carrier in an acidic solution, allowing it to stand, then washing it with water until it is neutral, allowing it to stand, filtering it, and then drying it to obtain a pretreated carrier;

[0008] S2, mixing the pretreated carrier, the silane coupling agent and the organic amine, performing a reflux reaction under stirring, washing with methanol, separating the solid and the liquid, and drying the separated solid to obtain a modified carrier;

[0009] S3:

[0010] S3-1, placing the modified carrier, template molecule and functional monomer in methanol, reacting under stirring to obtain a pre-assembled mixed solution;

[0011] S3-2, adding a crosslinking agent and an initiator to the pre-assembled mixed solution, and reacting with ultrasound under an inert atmosphere; filtering the solution after the reaction, washing the separated solid with an organic solvent to elute the template molecule, and then washing with deionized water until neutral, separating the solid and the liquid, and drying the separated solid to obtain a modified carrier loaded with a molecularly imprinted polymer;

[0012] S4, adding the modified carrier loaded with the molecular imprinting polymer to a nickel soluble metal salt aqueous solution, adding alkali to adjust the pH to 9-11, and impregnating under stirring; then adding a reducing agent to carry out a reduction reaction, standing after ultrasonication, separating the solid and the liquid, washing the separated solid with water until it is neutral, and drying to obtain the hydrogenation catalyst with molecular imprinting function.

[0013] In some embodiments, in the above method, in step S1, the mass ratio of the carrier to the acidic solution is 1:(7.5-10);

[0014] The carrier is selected from one of activated carbon, graphene, carbon black, acetylene black, aluminum oxide, zirconium oxide, titanium oxide, and diatomaceous earth, preferably selected from one of activated carbon, graphene, and carbon black;

[0015] The acidic solution is a hydrochloric acid aqueous solution, and the concentration of hydrochloric acid is 3-6 mol / L;

[0016] The standing conditions are: temperature of 25-50°C and time of 12-14h; and / or

[0017] The drying conditions are: temperature of 80-120° C. and time of 6-9 hours.

[0018] In some embodiments, in any of the above methods, in step S2, the mass ratio of the pretreated support, the silane coupling agent and the organic amine is 1:(0.5-0.7):(0.35-0.6);

[0019] The silane coupling agent is selected from one or more of vinyl triethoxy silane, vinyl trimethoxy silane, and vinyl tri (β-methoxyethoxy) silane;

[0020] The organic amine is an aliphatic amine, preferably one or more of trimethylamine, triethylamine and tripropylamine;

[0021] The reflux reaction conditions are: temperature of 80-140°C and time of 10-15h;

[0022] The stirring speed is 200-600 rpm; and / or

[0023] The drying conditions are: temperature of 100-150° C. and time of 16-24 hours.

[0024] In some embodiments, in any of the above methods, in step S3-1, the mass ratio of the modified carrier, template molecule, functional monomer and methanol is 1:(0.1-0.3):(0.8-1.2):(50-100);

[0025] The template molecule is an aromatic hydroxylamine compound, preferably one or more of N-[1-(3-amino-phenyl)-ethyl]-hydroxylamine, N-benzylhydroxylamine, and N-phenylhydroxylamine;

[0026] The functional monomer is selected from one or more of methacrylic acid, acrylamide, acrylic acid, and N-benzyl acrylamide;

[0027] The stirring speed is 200-350 rpm; and / or

[0028] The reaction conditions are: temperature of 30-50°C and time of 10-12h.

[0029] In some embodiments, in any of the above methods, in step S3-2, the mass ratio of the modified support, the crosslinking agent and the initiator is 1:(2.5-5):(0.1-0.3);

[0030] The cross-linking agent is ethylene glycol dimethacrylate and / or methylene bisacrylamide;

[0031] The initiator is azobisisobutyronitrile and / or tetrahydrofuran;

[0032] The inert atmosphere is one of nitrogen, argon and helium;

[0033] The conditions of the ultrasonic reaction are: temperature of 50-70°C and time of 18-24h;

[0034] The organic solvent is selected from one or more of methanol, ethanol, acetone, and acetic acid, preferably a mixed solution of methanol and acetic acid, such as a mixed solution of methanol and acetic acid in a mass ratio of 1:5-5:1; and / or

[0035] The drying conditions are: temperature of 100-150° C. and time of 10-15 hours.

[0036] In some embodiments, in any of the above methods, in step S4, the mass ratio of the modified support loaded with the molecularly imprinted polymer to the aqueous solution of the soluble metal salt of nickel is 1:(10-30), for example 1:20;

[0037] The concentration of the soluble metal salt aqueous solution of nickel is 2.5-3wt%;

[0038] The soluble metal salt of nickel is selected from one or more of nitrate, acetate and chloride;

[0039] The alkali is selected from potassium hydroxide, sodium hydroxide, and ammonia water (e.g., 15-25wt% ammonia water);

[0040] The immersion conditions are: temperature of 30-40°C and time of 6-9h;

[0041] The reducing agent is one or more of hydrogen, formaldehyde, hydrazine hydrate, and sodium sulfite, for example, a 30-50 wt % hydrazine hydrate aqueous solution with a mass of 30-40 times that of the modified support loaded with the molecularly imprinted polymer is used;

[0042] The reduction reaction time is 4-6h; and / or

[0043] The drying conditions are: temperature of 100-150° C. and time of 10-15 hours.

[0044] In a second aspect, the present invention provides a hydrogenation catalyst having molecular imprinting function prepared by any of the methods described above.

[0045] In some embodiments, based on 100 wt% of the total mass of the hydrogenation catalyst having molecular imprinting function, the content of nickel is 9-20 wt%.

[0046] In a third aspect, the present invention provides use of any of the above-mentioned hydrogenation catalysts having molecular imprinting function in catalyzing the hydrogenation of aromatic nitro compounds to prepare aromatic amines.

[0047] In some embodiments, in the above application, the aromatic nitro compound is dinitrotoluene (DNT), and the aromatic amine is toluenediamine (TDA).

[0048] In a fourth aspect, the present invention provides a method for preparing aromatic amines, comprising the step of using any of the above-mentioned hydrogenation catalysts with molecular imprinting function to catalyze a hydrogenation reaction of an aromatic nitro compound.

[0049] In some embodiments, in the above method, the aromatic nitro compound is dinitrotoluene, and the aromatic amine is toluenediamine.

[0050] In some embodiments, in any of the above methods, during the hydrogenation reaction, the mass ratio of hydrogen to dinitrotoluene is (6-10):1; and / or

[0051] The mass space velocity of dinitrotoluene is 5-6 kg DNT / (kg catalyst*h);

[0052] The method can be carried out continuously or intermittently in a conventional reactor with conventional process parameters (such as pressure and temperature), using the catalyst, dinitrotoluene as a raw material, and hydrogenating under hydrogen conditions to prepare toluenediamine; preferably, the reaction pressure is 5-70 barg, more preferably 10-25 barg, particularly preferably 20-25 barg, such as 21 barg; the reaction temperature is 100-300°C, more preferably 120-270°C, particularly preferably 120-140°C, such as 125°C.

[0053] Compared with the prior art, the present invention has the following advantages:

[0054] 1. The catalyst of the present invention adopts molecular imprinting technology to imprint the surface of the catalyst carrier, thereby strengthening the competitive adsorption performance of the catalyst for the hydroxylamine group on the aromatic ring, thereby reducing the generation of by-products caused by the hydroxylamine condensation reaction during the nitro hydrogenation reaction; the carrier surface modified by the molecular imprinting polymer significantly reduces the loading amount of the active component without reducing the activity of the catalyst, reduces the active center density on the catalyst surface, and inhibits the co-adsorption of the aromatic ring and hydrogen, effectively preventing the hydrogenation of the aromatic ring, reducing the generation of by-products caused by the over-hydrogenation of the reaction raw materials, and greatly improving the reaction yield and selectivity.

[0055] 2. The surface-imprinted carrier exhibits better mechanical strength, excellent compression resistance and thermal conductivity, and longer service life. At the same time, the reduction in the loading amount of active components can significantly reduce the catalyst cost. DETAILED DESCRIPTION

[0056] The present invention will be further described below in conjunction with specific examples. It should be understood that the following examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. Unless otherwise specified, the technical means used in the examples are conventional operations in the art, or according to the experimental methods recommended by the kit and instrument manufacturers. The reagents and biological materials used in the examples can be obtained from commercial sources unless otherwise specified.

[0057] The nickel content was determined using an AA240FS atomic absorption spectrophotometer from VARIAN.

[0058] Raney nickel is a product of Evonik, catalog number MC507.

[0059] Pd+Pt / C precious metal catalyst is a product of Xi'an Kaili New Materials Co., Ltd.

[0060] The contents of tar, TDA and light components were analyzed using a GC9160 gas chromatograph, using a SE-30 capillary column (0.32 mm × 0.33 μm × 30 m) and a hydrogen flame ionization detector (FID). 2 Flow rate 30mL·min -1 , H 2 Flow rate 20mL·min -1 , air flow rate 200mL·min -1 , column temperature 100℃, injector temperature 230℃, detector temperature 200℃, injection volume 1.0μL, injection split ratio 60: 1. The product content was calculated by area correction normalization method, and the correction factor was determined by external standard.

[0061] In the following examples, the frequency of ultrasound is 40 kHz.

[0062] Example 1

[0063] 1. Weigh 40g of activated carbon and place it in 320g of hydrochloric acid aqueous solution (hydrochloric acid concentration is 5mol / L), let it stand at 30°C for 12h, then rinse it with deionized water until it is neutral, let it stand and filter it, and then dry it at 80°C for 6h to obtain acid-activated activated carbon, that is, the pretreated carrier.

[0064] 2. Weigh 20 g of the pretreated carrier and place it in a container. Slowly add 10 g of vinyltriethoxysilane and 10 g of tripropylamine. Reflux reaction at 100 °C and 200 rpm stirring speed for 12 h. Wash 5 times with 100 g of methanol, separate the solid and liquid, and dry the separated solid at 100 °C for 24 h to obtain a modified carrier.

[0065] 3. Place 10g of the modified carrier, 1g of N-[1-(3-amino-phenyl)-ethyl]-hydroxylamine, and 8g of methacrylic acid in 1000g of methanol, and mix and react for 10h at 30°C and 300rpm stirring speed to obtain a pre-assembled mixed solution; add 40g of ethylene glycol dimethacrylate and 2g of azobisisobutyronitrile to the pre-assembled mixed solution, and ultrasonically react for 18h at 60°C and nitrogen atmosphere. The reacted solution was allowed to stand and filtered, and the separated solid was washed 5 times with a mixed solution of 100g of methanol + 20g of glacial acetic acid, and then washed with deionized water until neutral, and the solid and liquid were separated. The separated solid was dried at 150°C for 10h to obtain a modified carrier loaded with a molecularly imprinted polymer.

[0066] 4. Weigh 2.5g of nickel chloride and dissolve it in 100g of deionized water and stir to fully dissolve the nickel chloride. Then add 5g of the modified carrier loaded with molecular imprinting polymer to the mixture, slowly drop 20wt% ammonia water to the mixture to adjust the pH to 10, and stir and immerse at 30°C for 6h. Then slowly add 200g of 50wt% hydrazine hydrate aqueous solution to the mixture and stir to carry out reduction reaction for 4h. After ultrasonication, stand for 1h, separate the solid and liquid, wash the separated solid with deionized water until neutral, and dry at 150°C for 10h to obtain catalyst A.

[0067] After testing, the nickel content in Catalyst A was 12.5 wt%.

[0068] Example 2

[0069] 1. Weigh 40g of activated carbon and place it in 400g of hydrochloric acid aqueous solution (hydrochloric acid concentration is 3mol / L), let it stand at 25°C for 14h, then rinse it with deionized water until it is neutral, let it stand and filter it, and then dry it at 100°C for 8h to obtain acid-activated activated carbon, that is, the pretreated carrier.

[0070] 2. Weigh 20 g of the pretreated carrier and place it in a container. Slowly add 14 g of vinyltriethoxysilane and 12 g of triethylamine. Reflux reaction at 80 ° C and 300 rpm stirring speed for 10 hours. Wash with 100 g of methanol 5 times, separate the solid and liquid, and dry the separated solid at 120 ° C for 22 hours to obtain a modified carrier.

[0071] 3. Place 10g of the modified carrier, 2g of N-[1-(3-amino-phenyl)-ethyl]-hydroxylamine, and 12g of methacrylic acid in 800g of methanol, and mix and react for 12h at 40°C and 200rpm stirring speed to obtain a pre-assembled mixed solution; add 50g of ethylene glycol dimethacrylate and 3g of azobisisobutyronitrile to the pre-assembled mixed solution, and ultrasonically react for 20h at 50°C and nitrogen atmosphere. The reacted solution was allowed to stand and filtered, and the separated solid was washed 5 times with a mixed solution of 80g of methanol + 40g of glacial acetic acid, and then washed with deionized water until neutral, and the solid and liquid were separated. The separated solid was dried at 150°C for 10h to obtain a modified carrier loaded with a molecularly imprinted polymer.

[0072] 4. Weigh 2.5 g of nickel nitrate and dissolve it in 100 g of deionized water and stir to fully dissolve the nickel nitrate. Then add 5 g of the modified carrier loaded with molecular imprinting polymer, slowly drop 15 wt% ammonia water into the mixture to adjust the pH to 11, and stir and immerse at 35°C for 7 h. Then slowly add 200 g of 35 wt% hydrazine hydrate aqueous solution and stir to carry out reduction reaction for 6 h. After ultrasonication, stand for 2 h, separate the solid and liquid, wash the separated solid with deionized water until neutral, and dry at 150°C for 10 h to obtain catalyst B.

[0073] After testing, the nickel content in Catalyst B was 9.3 wt %.

[0074] Example 3

[0075] 1. Weigh 40g of activated carbon and place it in 350g of hydrochloric acid aqueous solution (hydrochloric acid concentration is 5mol / L), let it stand at 30°C for 12h, then rinse it with deionized water until it is neutral, let it stand and filter it, and then dry it at 110°C for 9h to obtain acid-activated activated carbon, that is, the pretreated carrier.

[0076] 2. Weigh 20 g of the pretreated carrier and place it in a container. Slowly add 11 g of vinyltrimethoxysilane and 8 g of triethylamine. Reflux reaction at 120 ° C and 400 rpm stirring speed for 15 hours. Wash with 100 g of methanol 5 times, separate the solid and liquid, and dry the separated solid at 150 ° C for 16 hours to obtain a modified carrier.

[0077] 3. Place 10g of the modified carrier, 1g of N-benzylhydroxylamine, and 8g of methacrylic acid in 500g of methanol, and mix and react for 10h at 50°C and 250rpm stirring speed to obtain a pre-assembled mixed solution; add 30g of ethylene glycol dimethacrylate and 1g of azobisisobutyronitrile to the pre-assembled mixed solution, and ultrasonically react for 24h at 70°C and nitrogen atmosphere. The reacted solution was allowed to stand and filtered, and the separated solid was washed 5 times with a mixed solution of 100g of methanol + 20g of glacial acetic acid, and then washed with deionized water until neutral, and the solid and liquid were separated. The separated solid was dried at 150°C for 10h to obtain a modified carrier loaded with a molecularly imprinted polymer.

[0078] 4. Weigh 3g of nickel acetate and dissolve it in 100g of deionized water and stir to fully dissolve the nickel acetate. Then add 5g of the modified carrier loaded with molecular imprinting polymer to the mixture, slowly drop 25wt% ammonia water to the mixture to adjust the pH to 11, and stir and immerse at 30°C for 9h. Then slowly add 200g of 30wt% hydrazine hydrate aqueous solution to the mixture and stir to carry out reduction reaction for 5h. After ultrasonication, stand for 1h, separate the solid and liquid, wash the separated solid with deionized water until neutral, and dry at 150°C for 10h to obtain catalyst C.

[0079] After testing, the nickel content in Catalyst C was 17.6 wt%.

[0080] Example 4

[0081] 1. Weigh 40g of activated carbon and place it in 300g of hydrochloric acid aqueous solution (hydrochloric acid concentration is 6mol / L), let it stand at 50°C for 14h, then rinse it with deionized water until it is neutral, let it stand and filter it, and then dry it at 120°C for 8h to obtain acid-activated activated carbon, that is, the pretreated carrier.

[0082] 2. Weigh 20 g of the pretreated carrier and place it in a container. Slowly add 11 g of vinyl tri(β-methoxyethoxy)silane and 7 g of tripropylamine. Reflux reaction at 140 ° C and 600 rpm stirring speed for 10 hours. Wash with 100 g of methanol 5 times, separate the solid and liquid, and dry the separated solid at 130 ° C for 17 hours to obtain a modified carrier.

[0083] 3. Place 10g of the modified carrier, 3g of N-phenylhydroxylamine, and 12g of methacrylic acid in 500g of methanol, and mix and react for 12h at 40°C and 350rpm stirring speed to obtain a pre-assembled mixed solution; add 25g of ethylene glycol dimethacrylate and 1.5g of azobisisobutyronitrile to the pre-assembled mixed solution, and ultrasonically react for 20h at 60°C and nitrogen atmosphere. The reacted solution was allowed to stand and filtered, and the separated solid was washed 5 times with a mixed solution of 20g of methanol + 100g of glacial acetic acid, and then washed with deionized water until neutral, and the solid and liquid were separated. The separated solid was dried at 150°C for 10h to obtain a modified carrier loaded with a molecularly imprinted polymer.

[0084] 4. Weigh 3 g of nickel nitrate and dissolve it in 100 g of deionized water and stir to fully dissolve the nickel nitrate. Then add 5 g of the modified carrier loaded with molecular imprinting polymer, slowly drop 20 wt% ammonia water into the mixture to adjust the pH to 9, and stir and immerse at 40°C for 6 h. Then slowly add 150 g of 35 wt% hydrazine hydrate aqueous solution and stir to carry out reduction reaction for 5 h. After ultrasonication, stand for 2 h, separate the solid and liquid, wash the separated solid with deionized water until neutral, and dry at 150°C for 10 h to obtain catalyst D.

[0085] After testing, the nickel content in Catalyst D was 19.7 wt %.

[0086] Example 5

[0087] The steps of Example 1 were repeated, except that the activated carbon in step 1 was replaced by the same mass of carbon black.

[0088] Finally, catalyst E was obtained.

[0089] After testing, the nickel content in Catalyst E was 12.8 wt %.

[0090] Comparative Example 1

[0091] Step 4 of Example 1 was repeated, except that the modified carrier loaded with the molecularly imprinted polymer was replaced with ordinary activated carbon of the same mass.

[0092] Finally, a comparative catalyst was obtained.

[0093] After testing, the nickel content in the comparative catalyst was 9.3 wt %.

[0094] Test Example 1

[0095] The catalysts prepared in Examples 1-5 and Comparative Example 1 as well as purchased Raney nickel and Pd+Pt / C noble metal catalysts were used in the hydrogenation reaction of dinitrotoluene to study the catalytic performance of different catalysts in catalyzing the hydrogenation of dinitrotoluene to prepare diaminotoluene (TDA).

[0096] In a 1L continuous fully mixed tank reactor, 200g of solvent (H 2 O 38.3wt%, TDA 61.7wt%) as the reaction base liquid, and add 4g catalyst, under room temperature, replace with high-purity nitrogen 3 times to remove the residual air inside the reactor, then replace with high-purity hydrogen 4 times until the hydrogen concentration in the replacement gas is greater than 99.9vol%, after the replacement is qualified, the reactor is pressurized to 21barg, the stirring speed is controlled to 1100rpm, and the reactor is heated to 125℃. The mass space velocity of dinitrotoluene is 5.7kg DNT / (kg catalyst*h), the mass ratio of hydrogen to dinitrotoluene is controlled to 8:1, the reaction liquid extraction rate is controlled to keep the liquid holding volume in the reactor at the initial value, and the reaction is started. After 12h of reaction, sampling is carried out, and the results are shown in Table 1. After continuing the reaction for 120h, sampling is carried out, and the results are shown in Table 2.

[0097] Table 1

[0098]

[0099] Table 2

[0100]

[0101] The results show that compared with traditional Raney nickel, noble metal catalysts and ordinary supported nickel catalysts, the hydrogenation catalyst with molecular imprinting function of the present invention has better selectivity and longer service life.

Claims

1. A method for preparing a hydrogenation catalyst having a molecular imprinting function, comprising the following steps: S1, placing the carrier in an acidic solution, allowing it to stand, then washing it with water until it is neutral, allowing it to stand, filtering it, and then drying it to obtain a pretreated carrier; S2, mixing the pretreated carrier, the silane coupling agent and the organic amine, performing a reflux reaction under stirring, washing with methanol, separating the solid and the liquid, and drying the separated solid to obtain a modified carrier; S3： S3-1, placing the modified carrier, template molecule and functional monomer in methanol, reacting under stirring to obtain a pre-assembled mixed solution; S3-2, adding a crosslinking agent and an initiator to the pre-assembled mixed solution, and reacting with ultrasound under an inert atmosphere; filtering the solution after the reaction, washing the separated solid with an organic solvent to elute the template molecule, and then washing with deionized water until neutral, separating the solid and the liquid, and drying the separated solid to obtain a modified carrier loaded with a molecularly imprinted polymer; S4, adding the modified carrier loaded with the molecular imprinting polymer to a nickel soluble metal salt aqueous solution, adding alkali to adjust the pH to 9-11, and impregnating under stirring; then adding a reducing agent to carry out a reduction reaction, standing after ultrasonication, separating the solid and the liquid, washing the separated solid with water until it is neutral, and drying to obtain the hydrogenation catalyst with molecular imprinting function.

2. The method according to claim 1, characterized in that: In the step S1, the mass ratio of the carrier to the acidic solution is 1:(7.5-10); The carrier is selected from one of activated carbon, graphene, carbon black, acetylene black, aluminum oxide, zirconium oxide, titanium oxide, and diatomaceous earth, preferably selected from one of activated carbon, graphene, and carbon black; The acidic solution is a hydrochloric acid aqueous solution with a concentration of 3-6 mol / L; The standing temperature is 25-50°C; and / or The drying temperature is 80-120°C.

3. The method according to claim 1 or 2, characterized in that: In the step S2, the mass ratio of the pretreated carrier, the silane coupling agent and the organic amine is 1:(0.5-0.7):(0.35-0.6); The silane coupling agent is selected from one or more of vinyl triethoxy silane, vinyl trimethoxy silane, and vinyl tri (β-methoxyethoxy) silane; The organic amine is an aliphatic amine, preferably one or more of trimethylamine, triethylamine and tripropylamine; The temperature of the reflux reaction is 80-140° C.; and / or The drying temperature is 100-150°C.

4. The method according to any one of claims 1 to 3, characterized in that: In the step S3-1, the mass ratio of the modified carrier, the template molecule, the functional monomer and methanol is 1:(0.1-0.3):(0.8-1.2):(50-100); The template molecule is an aromatic hydroxylamine compound, preferably one or more of N-[1-(3-amino-phenyl)-ethyl]-hydroxylamine, N-benzylhydroxylamine, and N-phenylhydroxylamine; The functional monomer is selected from one or more of methacrylic acid, acrylamide, acrylic acid, and N-benzyl acrylamide; and / or The reaction temperature is 30-50°C.

5. The method according to any one of claims 1 to 4, characterized in that: In the step S3-2, the mass ratio of the modified carrier, the crosslinking agent and the initiator is 1:(2.5-5):(0.1-0.3); The cross-linking agent is ethylene glycol dimethacrylate and / or methylene bisacrylamide; The initiator is azobisisobutyronitrile and / or tetrahydrofuran; The inert atmosphere is one of nitrogen, argon and helium; The temperature of the ultrasonic reaction is 50-70°C; The organic solvent is selected from one or more of methanol, ethanol, acetone and acetic acid, preferably a mixed solution of methanol and acetic acid; and / or The drying temperature is 100-150°C.

6. The method according to any one of claims 1 to 5, characterized in that: In the step S4, the mass ratio of the modified support loaded with the molecular imprinting polymer to the aqueous solution of the soluble metal salt of nickel is 1:(10-30); The concentration of the soluble metal salt aqueous solution of nickel is 2.5-3wt%; The soluble metal salt of nickel is selected from one or more of nitrate, acetate and chloride; The alkali is selected from potassium hydroxide, sodium hydroxide, and ammonia; The immersion temperature is 30-40°C; The reducing agent is one or more of hydrogen, formaldehyde, hydrazine hydrate, and sodium sulfite; and / or The drying temperature is 100-150°C.

7. A hydrogenation catalyst with molecular imprinting function prepared by the method according to any one of claims 1 to 6.

8. The hydrogenation catalyst with molecular imprinting function according to claim 7, characterized in that: Based on the total mass of the hydrogenation catalyst with molecular imprinting function being 100wt%, the content of nickel is 9-20wt%.

9. Use of the hydrogenation catalyst with molecular imprinting function according to claim 7 or 8 in catalyzing the hydrogenation of aromatic nitro compounds to prepare aromatic amines.

10. A method for preparing aromatic amines, comprising the step of using the hydrogenation catalyst with molecular imprinting function as claimed in claim 7 or 8 to catalyze the hydrogenation reaction of aromatic nitro compounds.

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