Supported copper-based catalysts, their preparation and use in the hydrogenation of nitrobenzene

Abstract

The application discloses a kind of supported copper-based catalyst and preparation and application.It includes the following steps: configuration copper salt solution;Copper salt solution is added to metal oxide carrier, reach equal-volume impregnation;After drying, it is calcined in muffle furnace at 300-500 DEG C for 2-12 hours.The obtained solid is reduced and treated in hydrogen atmosphere at 200-400 DEG C for 1-4 hours, then put into organic solution;Another metal oxide carrier is added to the solution, and the mixed solution is heated to 100-170 DEG C;After centrifugal washing, supported copper-based catalyst is obtained.The preparation method disclosed in the application can realize the migration of copper species between different metal oxides at low temperature, and obtain supported copper-based catalyst with different dispersity and electronic state.The application provides the application of the prepared supported copper-based catalyst in nitrobenzene hydrogenation, with high activity and high selectivity.The preparation method is simple, low in cost and conducive to industrial application.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of catalysis technology, and particularly relates to a supported copper-based catalyst and preparation and application thereof in preparation of aniline from nitrobenzene hydrogenation. BACKGROUND

[0002] Aniline accounts for a huge share in the market of organic chemical industry, and is an important synthetic unit of organic chemicals such as medicines, dyes and pesticides. Selective reduction of nitrobenzene is the best route for preparing aniline. Selective reduction of nitrobenzene to prepare aniline can be realized by using alkaline metal as a reducing agent, however, a large amount of by-product iron oxide has exceeded the market demand, resulting in high economic cost of the process route.

[0003] At present, hydrogen is used as the most commonly used and cheapest industrial reducing gas for selective hydrogenation of nitrobenzene to produce aniline. The catalyst system for preparing aniline from nitrobenzene hydrogenation at present mainly includes supported Pd, Pt, Au and other noble metal systems, and supported Ni, Fe, Co and other non-noble metal systems. The noble metal catalysts exhibit high activity in the hydrogenation process, however, the strong hydrogenation ability thereof causes over-hydrogenation to produce supersaturated products in the hydrogenation process.

[0004] Patent CN108295843A discloses a method for preparing three-dimensional graphene supported nano-Pd catalyst by soft film plate method. A certain amount of graphite oxide is added into an emulsion system of deionized water, ethanol and cyclohexane, the concentration of graphite oxide is 0.5-4 mg / mL, then ultrasonic treatment is carried out at room temperature for 5-20 min to obtain dispersed graphene oxide emulsion; 60-100 mg of ascorbic acid is added into the emulsion obtained in the step, and the mixture is treated at 60-90℃ in water bath for 0.25-2 h; then 0.3-1 mL of PdCl2 aqueous solution with a concentration of 0.02 mol / L is added, and the mixture is stirred in an oil bath; the obtained mixture is centrifuged, washed with deionized water and ethanol in sequence, and vacuum dried to obtain the catalyst. In the method, graphite oxide is used as a carrier, ascorbic acid and noble metal Pt are used at the same time, so that the cost of industrial application is too high, and the production is limited. At present, the non-noble metal catalysts developed by industry include sulfides of Ni, composite catalysts of Cu, Mn and Fe, and the operation needs to be above 300℃, and the high reaction temperature brings problems such as high energy consumption and poor stability of the catalyst.

[0005] In summary, in the process of preparing aniline from nitrobenzene hydrogenation, there are generally problems of high catalyst activity, poor selectivity, high catalyst cost and low reaction activity at low temperature. Therefore, it is of great significance to develop a catalyst preparation method with high activity and low cost. SUMMARY

[0006] The present application aims at solving the problems of low activity and high cost of catalysts in the process of preparing aniline from nitrobenzene, and provides a cheap and easy-to-prepare supported copper-based catalyst with high activity and selectivity in catalyzing the hydrogenation of nitrobenzene.

[0007] To achieve the object of the present application, the present application adopts the following technical solutions:

[0008] The present application provides a preparation method of a supported copper-based catalyst, comprising the following steps:

[0009] (1) dissolving copper salt in water to obtain a copper salt solution;

[0010] (2) impregnating the copper salt solution into metal oxide A in equal volume, and drying in a constant temperature oven at 40-120℃ for 4-24 hours; after drying, calcining the solid in a muffle furnace at 300-500℃ (preferably 380-420℃, more preferably 400-410℃) for 2-12 hours; and reducing treatment at 200-400℃ (preferably 280-320℃, more preferably 290-300℃) in a hydrogen-containing atmosphere for 1-6 hours (preferably 1.5-2 hours);

[0011] (3) putting the obtained solid into an organic solvent, and adding another metal oxide B; heating the mixed solution to 100-170℃ (preferably 120-150℃, more preferably 130-140℃) for 1-24 hours; centrifugal washing to obtain the supported copper-based catalyst.

[0012] The mass ratio of copper to metal oxide A in the prepared supported copper-based catalyst is 1-10% (preferably 1.5-3%, more preferably 1.9-2.1%); the mass ratio of metal oxide A to metal oxide B is 0.1-10, preferably 0.2-2, more preferably 0.8-1.2;

[0013] The copper salt is one or more of copper nitrate, copper sulfate, copper chloride and copper acetate;

[0014] The molecular formula of the copper nitrate is Cu(NO3)2·xH2O (x=0, 3 or 6), the molecular formula of the copper sulfate is CuSO4·yH2O (x=0, 1, 3 or 5), the molecular formula of the copper chloride is CuCl2·zH2O (x=0 or 2), and the molecular formula of the copper acetate is Cu(CH3COO)2·wH2O (x=0 or 1);

[0015] The metal oxide A is one or more of Al2O3, SiO2 or TiO2 (preferably TiO2); the metal oxide B is one or more of Nb2O5, CeO2 or ZrO2 (preferably CeO2); the mass ratio of the metal oxide A to the metal oxide B is 0.1-10 (preferably 0.2-2);

[0016] The organic solvent is one or more of methanol, ethanol, hexane, heptane, octane, toluene, xylene, trimethylbenzene, ethylbenzene, acetonitrile or 1,4-dioxane;

[0017] The hydrogen-containing atmosphere is hydrogen or a mixture of hydrogen and an inert gas; the inert gas includes one or more of nitrogen, argon or helium; the volume fraction of hydrogen in the hydrogen-containing atmosphere is 1-100%;

[0018] The application provides application of the supported copper-based catalyst prepared by the preparation method in nitrobenzene hydrogenation.

[0019] The reaction is specifically that the prepared supported copper-based catalyst is placed in a high-pressure reaction kettle, organic solvent and nitrobenzene are added, a reducing agent is added, and the reaction is promoted under heating conditions.

[0020] The organic solvent is one or more of methanol, ethanol, toluene, xylene, 1,4-dioxane or cyclohexane; the reducing agent is H2; the heating condition temperature is 100-160 DEG C, preferably 120-150 DEG C, more preferably 130-140 DEG C; and the time is 0.5-10 hours, preferably 1-5 hours, more preferably 2-3 hours.

[0021] The H2 has a pressure of 0.2-5 MPa.

[0022] The preparation method disclosed by the application can realize migration of copper species between different metal oxides at low temperature, and obtain supported copper-based catalysts with different dispersities and electronic states. The application provides application of the prepared supported copper-based catalyst in nitrobenzene hydrogenation, and the catalyst has high activity and high selectivity. The preparation method is simple, low in cost and beneficial to industrial application. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 The high-magnification transmission electron microscope picture of the supported copper-based catalyst Cu / TiO2-CeO2-1 obtained in Example 1 and the corresponding EDS line scanning element analysis; the results show that part of Cu migrates from TiO2 to CeO2;

[0024] Figure 2Transmission electron microscope picture of the supported copper-based catalyst Cu / TiO2-CeO2-1 obtained in Example 1; the size of CeO2 ranges from 5 to 10 nanometers, and the size of TiO2 ranges from 30 to 60 nanometers, and the results show that CeO2 is in close contact with TiO2.

[0025] Figure 3 Transmission electron microscope picture of the supported copper-based catalyst Cu / TiO2-CeO2-2 obtained in Example 2; the size of CeO2 ranges from 5 to 10 nanometers, and the size of TiO2 ranges from 30 to 60 nanometers, and the results show that CeO2 is in close contact with TiO2. DETAILED DESCRIPTION

[0026] To further illustrate the present application, the detailed preparation process is described below in conjunction with specific examples, but only for detailed description of the present application, and cannot be regarded as a limitation of the protection scope of the present application.

[0027] Example 1

[0028] Preparation of Cu / TiO2-CeO2-1:

[0029] (1) Dissolve 0.228 g of copper nitrate trihydrate in 1.6 mL of ultrapure water, and wait until it is completely dissolved to form a uniform solution; dropwise add the solution to 3 g of rutile titanium oxide (TiO2-R) carrier while stirring until it reaches the saturated adsorption amount (i.e. equal volume impregnation), at which time the prepared solution is completely absorbed and the metal ions are completely loaded onto the carrier to obtain a sample;

[0030] (2) Place the sample obtained in step (1) in a 100°C air oven for drying for 12 hours, and then place it in a muffle furnace for calcination at 400°C for 4 hours; weigh 51 mg of the obtained solid and place it in a 30 vol.% H2 / N2 mixed gas at 300°C for reduction for 2 hours to obtain a reduced sample;

[0031] (3) Place the reduced sample in step (2) in a 20 mL high-pressure reaction kettle, add 2 mL of toluene; then add 50 mg of cerium oxide, and fill the high-pressure reaction kettle with 2 MPa of H2; heat to 140°C and maintain for 3 hours;

[0032] (4) Centrifuge the treated material obtained in step (3), wash the solid, and dry (100°C vacuum drying for 6 hours) to obtain a supported copper-based catalyst with a mass ratio of copper to TiO2-R of 2%, and a mass ratio of TiO2-R to cerium oxide of 1:1;

[0033] The catalyst prepared above was used in the evaluation of catalytic hydrogenation of nitrobenzene in a high-pressure reactor. When the reaction conditions were as follows: catalyst dosage 101 mg, nitrobenzene 90 mg, toluene 2 mL, H2 2 MPa, reaction temperature 140°C, and reaction time 3 hours, the conversion rate of nitrobenzene was 99.8% and the selectivity of aniline was 99.9%.

[0034] Example 2

[0035] Preparation of Cu / TiO2-CeO2-2:

[0036] (1) 0.456 g of copper nitrate trihydrate was dissolved in 1.6 mL of ultrapure water, and a uniform solution was formed after complete dissolution. The solution was added dropwise to 3 g of rutile titanium oxide (TiO2-R) carrier while stirring until it reached the saturation adsorption amount (i.e., equal-volume impregnation), at which time the prepared solution was completely absorbed and the metal ions were completely loaded onto the carrier to obtain a sample;

[0037] (2) The sample obtained in step (1) was dried in a 100°C air oven for 12 hours, and then calcined in a muffle furnace at 400°C for 4 hours. 52 mg of the obtained solid was placed in a 30 vol.% H2 / N2mixed gas at 300°C for 2 hours to obtain a reduced sample;

[0038] (3) The reduced sample in step (2) was placed in a 20 mL high-pressure reactor, and 2 mL of toluene was added. Then, 50 mg of cerium oxide was added, and the high-pressure reactor was filled with 2 MPa of H2. The temperature was raised to 140°C and maintained for 3 hours;

[0039] (4) The treated material obtained in step (3) was centrifuged, the solid was washed and dried (100°C vacuum drying for 6 hours) to obtain a supported copper-based catalyst with a mass ratio of copper to TiO2-R of 4%, and a mass ratio of TiO2-R to cerium oxide of 1:1;

[0040] The catalyst prepared above was used in the evaluation of catalytic hydrogenation of nitrobenzene in a high-pressure reactor. When the reaction conditions were as follows: catalyst dosage 101 mg, nitrobenzene 90 mg, toluene 2 mL, H2 2 MPa, reaction temperature 140°C, and reaction time 3 hours, the conversion rate of nitrobenzene was 99.8% and the selectivity of aniline was 99.9%.

[0041] Example 3

[0042] Preparation of Cu / TiO2-CeO2-3:

[0043] (1) Dissolve 0.228 g of copper nitrate trihydrate in 1.6 mL of ultrapure water, and wait until it is completely dissolved to form a uniform solution; drop the solution onto 3 g of rutile titanium oxide (TiO2-R) carrier drop by drop while stirring until it reaches the saturated adsorption amount (i.e. equal volume impregnation), at which time the prepared solution is just completely absorbed, and the metal ions are completely loaded onto the carrier to obtain a sample;

[0044] (2) Place the sample obtained in step (1) in a 100°C air oven for drying for 12 hours, and then place it in a muffle furnace for calcination at 400°C for 4 hours; weigh 51 mg of the obtained solid, and place it in a 30 vol.% H2 / N2mixed gas at 300°C for reduction for 2 hours to obtain a reduced sample;

[0045] (3) Place the reduced sample in step (2) in a 20 mL high-pressure reaction kettle, and add 2 mL of toluene; then add 100 mg of cerium oxide, and fill the high-pressure reaction kettle with 2 MPa of H2; heat to 140°C, and keep for 3 hours;

[0046] (4) Centrifuge the treated material obtained in step (3), wash the solid, and dry (vacuum drying at 100°C for 6 hours) to obtain a supported copper-based catalyst with a mass ratio of copper to TiO2-R of 2%, and a mass ratio of TiO2-R to cerium oxide of 1:2;

[0047] The catalyst prepared above is used for evaluation of catalytic hydrogenation of nitrobenzene in a high-pressure reaction kettle, and under the reaction conditions of: catalyst dosage 151 mg, nitrobenzene 90 mg, toluene 2 mL, H2 2 MPa, reaction temperature 140°C, and reaction time 3 hours, the conversion rate of nitrobenzene is 92.2%, and the selectivity of aniline is 99.9%.

[0048] Example 4

[0049] Preparation of Cu / TiO2-CeO2-4:

[0050] (1) Dissolve 0.228 g of copper nitrate trihydrate in 1.6 mL of ultrapure water, and wait until it is completely dissolved to form a uniform solution; drop the solution onto 3 g of rutile titanium oxide (TiO2-R) carrier drop by drop while stirring until it reaches the saturated adsorption amount (i.e. equal volume impregnation), at which time the prepared solution is just completely absorbed, and the metal ions are completely loaded onto the carrier to obtain a sample;

[0051] (2) Place the sample obtained in step (1) in a 100°C air oven for drying for 12 hours, and then place it in a muffle furnace for calcination at 400°C for 4 hours; weigh 51 mg of the obtained solid, and place it in a 30 vol.% H2 / N2mixed gas at 300°C for reduction for 2 hours to obtain a reduced sample;

[0052] (3) The reduced sample from step (2) was placed in a 20 mL autoclave, 2 mL of toluene was added; 100 mg of cerium oxide was added, 2 MPa of Ar was filled in the autoclave; the temperature was raised to 140°C and maintained for 3 hours;

[0053] (4) The treated material from step (3) was centrifuged, the solid was washed and dried (vacuum drying at 100°C for 6 hours) to obtain a supported copper-based catalyst with a mass ratio of copper to TiO2-R of 2%, and a mass ratio of TiO2-R to cerium oxide of 1:2;

[0054] The above-prepared catalyst was used to evaluate the catalytic hydrogenation of nitrobenzene in an autoclave, under the reaction conditions: catalyst dosage 101 mg, nitrobenzene 90 mg, toluene 2 mL, H2 2 MPa, reaction temperature 140°C, and reaction time 3 hours, the conversion rate of nitrobenzene was 82.6%, and the selectivity of aniline was 99.9%.

[0055] Example 5

[0056] Preparation of Cu / TiO2-CeO2-5:

[0057] (1) 0.228 g of copper nitrate trihydrate was dissolved in 1.6 mL of ultrapure water, and a uniform solution was formed after complete dissolution; the solution was added dropwise to 3 g of rutile titanium oxide (TiO2-R) carrier while stirring until it reached the saturation adsorption amount (i.e. equal volume impregnation), at which point the prepared solution was completely absorbed and the metal ions were completely loaded onto the carrier to obtain a sample;

[0058] (2) The sample obtained in step (1) was dried in a 100°C air oven for 12 hours, and then calcined in a muffle furnace at 400°C for 4 hours; 51 mg of the obtained solid was placed in a 20 vol.% H2 / N2 mixed gas and reduced at 300°C for 2 hours to obtain a reduced sample;

[0059] (3) The reduced sample from step (2) was placed in a 20 mL autoclave, 2 mL of toluene was added; 100 mg of cerium oxide was added, 2 MPa of Ar was filled in the autoclave; the temperature was raised to 140°C and maintained for 3 hours;

[0060] (4) The treated material from step (3) was centrifuged, the solid was washed and dried (vacuum drying at 100°C for 6 hours) to obtain a supported copper-based catalyst with a mass ratio of copper to TiO2-R of 2%, and a mass ratio of TiO2-R to cerium oxide of 1:2;

[0061] The catalyst prepared above was used in the evaluation of catalytic hydrogenation of nitrobenzene in a high-pressure reactor. When the reaction conditions were as follows: catalyst dosage 101 mg, nitrobenzene 90 mg, toluene 2 mL, H2 2 MPa, reaction temperature 140°C, and reaction time 3 hours, the conversion rate of nitrobenzene was 93.6% and the selectivity of aniline was 99.9%.

[0062] Example 6

[0063] Preparation of Cu / TiO2-CeO2-6:

[0064] (1) 0.228 g of copper nitrate trihydrate was dissolved in 1.6 mL of ultrapure water, and a uniform solution was formed after complete dissolution. The solution was added dropwise to 3 g of rutile titanium oxide (TiO2-R) carrier while stirring until it reached the saturation adsorption amount (i.e., equal-volume impregnation), at which time the prepared solution was completely absorbed and the metal ions were completely loaded onto the carrier to obtain a sample;

[0065] (2) The sample obtained in step (1) was dried in a 100°C air oven for 12 hours and then calcined in a muffle furnace at 400°C for 4 hours. 51 mg of the obtained solid was placed in a 30 vol.% H2 / N2mixed gas at 280°C for 2 hours to obtain a reduced sample;

[0066] (3) The reduced sample in step (2) was placed in a 20 mL high-pressure reactor, and 2 mL of toluene was added. Then, 50 mg of cerium oxide was added, and the high-pressure reactor was filled with 2 MPa of H2. The temperature was raised to 140°C and maintained for 3 hours;

[0067] (4) The treated material obtained in step (3) was centrifuged, the solid was washed and dried (vacuum drying at 100°C for 6 hours) to obtain a supported copper-based catalyst with a mass ratio of copper to TiO2-R of 2%, and a mass ratio of TiO2-R to cerium oxide of 1:1;

[0068] The catalyst prepared above was used in the evaluation of catalytic hydrogenation of nitrobenzene in a high-pressure reactor. When the reaction conditions were as follows: catalyst dosage 101 mg, nitrobenzene 90 mg, toluene 2 mL, H2 2 MPa, reaction temperature 140°C, and reaction time 3 hours, the conversion rate of nitrobenzene was 93.6% and the selectivity of aniline was 99.9%.

[0069] Example 7

[0070] Preparation of Cu / TiO2-ZrO2:

[0071] (1) 0.228 g of copper nitrate trihydrate was dissolved in 1.6 mL of ultrapure water, and the solution was added dropwise to 3 g of rutile titanium oxide (TiO2-R) carrier while stirring until the solution was completely absorbed, i.e., the metal ions were completely loaded onto the carrier, to obtain a sample;

[0072] (2) The sample obtained in step (1) was dried in a 100°C air oven for 12 hours, and then calcined in a muffle furnace at 400°C for 4 hours. 51 mg of the obtained solid was placed in a 30 vol.% H2 / N2 mixed gas at 300°C for 2 hours to obtain a reduced sample;

[0073] (3) The reduced sample in step (2) was placed in a 20 mL high-pressure reactor, and 2 mL of toluene was added. Then 50 mg of zirconium oxide was added, and the high-pressure reactor was filled with 2 MPa of H2. The temperature was raised to 140°C and maintained for 3 hours;

[0074] (4) The treated material obtained in step (3) was centrifuged, the solid was washed and dried (100°C vacuum drying for 6 hours) to obtain a supported copper-based catalyst with a mass ratio of copper to cerium oxide of 2%. The mass ratio of TiO2-R to zirconium oxide was 1:1;

[0075] The above-prepared catalyst was used to evaluate the catalytic hydrogenation of nitrobenzene in a high-pressure reactor. Under the reaction conditions of: catalyst dosage 101 mg, nitrobenzene 90 mg, toluene 2 mL, H2 2 MPa, reaction temperature 140°C, and reaction time 3 hours, the conversion rate of nitrobenzene was 90.8%, and the selectivity of aniline was 99.9%.

[0076] Comparative Example 1

[0077] Preparation of Cu / TiO2-CeO2-D1:

[0078] (1) 0.228 g of copper nitrate trihydrate was dissolved in 1.6 mL of ultrapure water, and the solution was added dropwise to 3 g of rutile titanium oxide (TiO2-R) carrier while stirring until the solution was completely absorbed, i.e., the metal ions were completely loaded onto the carrier, to obtain a sample;

[0079] (2) The sample obtained in step (1) was dried in a 100°C air oven for 12 hours, and then calcined in a muffle furnace at 400°C for 4 hours;

[0080] (3) Take 51 mg of the calcined sample in step (2) and place it in a 20 mL high-pressure reactor, add 2 mL of toluene; add 50 mg of cerium oxide, and fill the high-pressure reactor with 2 MPa of H2; heat to 140°C and maintain for 3 hours;

[0081] (4) Centrifuge the treated material obtained in step (3), wash the solid, and dry (vacuum drying at 100°C for 6 hours) to obtain a supported copper-based catalyst with a mass ratio of copper to TiO2-R of 2%, and a mass ratio of TiO2-R to cerium oxide of 1:1.

[0082] The above-prepared catalyst was used to evaluate the catalytic hydrogenation of nitrobenzene in a high-pressure reactor, and under the reaction conditions of: catalyst dosage 101 mg, nitrobenzene 90 mg, toluene 2 mL, H2 2 MPa, reaction temperature 140°C, and reaction time 3 hours, the conversion rate of nitrobenzene was 23.2%, and the selectivity of aniline was 66.8%.

[0083] Comparative Example 2

[0084] Preparation of Cu / CeO2-D2:

[0085] (1) Dissolve 0.228 g of copper nitrate trihydrate in 1.1 mL of ultrapure water, and when it is completely dissolved to form a uniform solution, add the solution dropwise to 3 g of cerium oxide while stirring until it reaches the saturation adsorption amount (i.e., equal-volume impregnation), at which point the prepared solution is completely absorbed, and the metal ions are completely loaded onto the carrier to obtain a sample;

[0086] (2) Place the sample obtained in step (1) in a 100°C air oven and dry for 12 hours, and then place it in a muffle furnace and calcine at 400°C for 4 hours; take 51 mg of the obtained solid and place it in a 30 vol.% H2 / N2 mixed gas at 300°C and reduce for 2 hours;

[0087] (3) Place the reduced sample in step (2) in a 20 mL high-pressure reactor, add 2 mL of toluene; fill the high-pressure reactor with 2 MPa of H2; heat to 140°C and maintain for 3 hours;

[0088] (4) Centrifuge the treated material obtained in step (3), wash the solid, and dry (vacuum drying at 100°C for 6 hours) to obtain a supported copper-based catalyst with a mass ratio of copper to cerium oxide of 2%.

[0089] The above-prepared catalyst was used to evaluate the catalytic hydrogenation of nitrobenzene in a high-pressure reactor, and under the reaction conditions of: catalyst dosage 51 mg, nitrobenzene 90 mg, toluene 2 mL, H2 2 MPa, reaction temperature 140°C, and reaction time 3 hours, the conversion rate of nitrobenzene was 46.2%, and the selectivity of aniline was 15.6%.

[0090] Comparative Example 3

[0091] Preparation of Cu / TiO2-CeO2-D3:

[0092] (1) 0.228 g of copper nitrate trihydrate was dissolved in 1.6 mL of ultrapure water, and a uniform solution was formed after complete dissolution. The solution was added dropwise to 3 g of rutile titanium oxide (TiO2-R) carrier while stirring until it reached the saturation adsorption amount (i.e., equal volume impregnation). At this time, the prepared solution was completely absorbed, and the metal ions were completely loaded onto the carrier to obtain a sample;

[0093] (2) The sample obtained in step (1) was dried in a 100°C air oven for 12 hours, and then calcined in a muffle furnace at 400°C for 4 hours. 51 mg of the obtained solid was placed in a 30 vol.% H2 / N2mixed gas at 300°C for 2 hours to obtain a reduced sample;

[0094] (3) The reduced sample in step (2) was placed in a 20 mL high-pressure reactor, and 2 mL of water was added. Then 50 mg of cerium oxide was added, and the high-pressure reactor was filled with 2 MPa of H2. The temperature was raised to 140°C and maintained for 3 hours;

[0095] (4) The treated material obtained in step (3) was centrifuged, the solid was washed and dried (100°C vacuum drying for 6 hours) to obtain a supported copper-based catalyst with a mass ratio of copper to TiO2-R of 2%, and a mass ratio of TiO2-R to cerium oxide of 1:1.

[0096] The above-prepared catalyst was used to evaluate the catalytic hydrogenation of nitrobenzene in a high-pressure reactor. Under the reaction conditions of: catalyst dosage 100 mg, nitrobenzene 90 mg, toluene 2 mL, H2 2 MPa, reaction temperature 140°C, and reaction time 3 hours, the conversion rate of nitrobenzene was 48.8%, and the selectivity of aniline was 69.5%.

[0097] Comparative Example 4

[0098] Preparation of Cu / TiO2-CeO2-D4:

[0099] (1) 0.228 g of copper nitrate trihydrate was dissolved in 1.6 mL of ultrapure water, and a uniform solution was formed after complete dissolution. The solution was added dropwise to 3 g of rutile titanium oxide (TiO2-R) carrier while stirring until it reached the saturation adsorption amount (i.e., equal volume impregnation). At this time, the prepared solution was completely absorbed, and the metal ions were completely loaded onto the carrier to obtain a sample;

[0100] (2) The sample obtained in step (1) was dried in a blast oven at 100°C for 12 hours, and then calcined in a muffle furnace at 400°C for 4 hours; 51 mg of the obtained solid was weighed and reduced in a 30 vol.% H2 / N2mixed gas at 300°C for 2 hours to obtain a reduced sample;

[0101] (3) The reduced sample in step (2) was placed in a 20 mL high-pressure reactor, 2 mL of toluene was added; then 1 mg of cerium oxide was added, and 2 MPa of H2was filled in the high-pressure reactor; the temperature was raised to 140°C and maintained for 3 hours;

[0102] (4) The treated material obtained in step (3) was centrifuged, the solid was washed and dried (vacuum drying at 100°C for 6 hours) to obtain a supported copper-based catalyst with a mass ratio of copper to TiO2-R of 2%, and a mass ratio of TiO2-R to cerium oxide of 1:0.02.

[0103] The above-prepared catalyst was used to evaluate the catalytic hydrogenation of nitrobenzene in a high-pressure reactor, and under the reaction conditions of: catalyst dosage 52 mg, nitrobenzene 90 mg, toluene 2 mL, H2 2 MPa, reaction temperature 140°C, and reaction time 3 hours, the conversion rate of nitrobenzene was 46.5%, and the selectivity of aniline was 52.8%.

[0104] Comparative Example 5

[0105] Preparation of Cu / TiO2-CeO2-D5:

[0106] (1) 0.228 g of copper nitrate trihydrate was dissolved in 1.6 mL of ultrapure water, and a uniform solution was formed after complete dissolution; the solution was added dropwise to 3 g of rutile titanium oxide (TiO2-R) carrier while stirring until it reached the saturation adsorption amount (i.e. equal volume impregnation), at which time the prepared solution was completely absorbed and the metal ions were completely loaded onto the carrier to obtain a sample;

[0107] (2) The sample obtained in step (1) was dried in a blast oven at 100°C for 12 hours, and then calcined in a muffle furnace at 400°C for 4 hours; 51 mg of the obtained solid was weighed and reduced in a 30 vol.% H2 / N2mixed gas at 300°C for 2 hours to obtain a reduced sample;

[0108] (3) The reduced sample in step (2) was placed in a 20 mL high-pressure reactor, 2 mL of toluene was added; then 1 mg of cerium oxide was added, and 2 MPa of H2was filled in the high-pressure reactor; the temperature was raised to 140°C and maintained for 3 hours;

[0109] (4) The treated material obtained in step (3) was centrifuged, the solid was washed and dried (vacuum drying at 100°C for 6 hours) to obtain a supported copper-based catalyst with a mass ratio of copper to TiO2-R of 2% and a mass ratio of TiO2-R to cerium oxide of 1:16.

[0110] The catalyst prepared above was used to evaluate the catalytic hydrogenation of nitrobenzene in a high-pressure reaction kettle. When the reaction conditions were as follows: catalyst dosage 851 mg, nitrobenzene 90 mg, toluene 2 mL, H2 2 MPa, reaction temperature 140°C, and reaction time 3 hours, the conversion rate of nitrobenzene was 56.2% and the selectivity of aniline was 24.8%.

[0111] Comparative Example 6

[0112] Preparation of Cu / CeO2-TiO2:

[0113] (1) 0.228 g of copper nitrate trihydrate was dissolved in 1.1 mL of ultrapure water, and a uniform solution was formed after complete dissolution. The solution was added dropwise to 3 g of cerium oxide carrier while stirring until the saturation adsorption amount was reached (i.e., equal-volume impregnation). At this time, the prepared solution was completely absorbed, and the metal ions were completely loaded onto the carrier to obtain a sample;

[0114] (2) The sample obtained in step (1) was dried in a 100°C air oven for 12 hours, and then calcined in a muffle furnace at 400°C for 4 hours. 51 mg of the obtained solid was placed in a 30 vol.% H2 / N2 mixed gas at 300°C for 2 hours to obtain a reduced sample;

[0115] (3) The reduced sample in step (2) was placed in a 20 mL high-pressure reaction kettle, and 2 mL of toluene was added. Then, 50 mg of rutile titanium oxide (TiO2-R) was added, and 2 MPa of H2 was filled into the high-pressure reaction kettle. The temperature was raised to 140°C and maintained for 3 hours;

[0116] (4) The treated material obtained in step (3) was centrifuged, the solid was washed and dried (vacuum drying at 100°C for 6 hours) to obtain a supported copper-based catalyst with a mass ratio of copper to TiO2-R of 2% and a mass ratio of TiO2-R to cerium oxide of 1:1;

[0117] The catalyst prepared above was used to evaluate the catalytic hydrogenation of nitrobenzene in a high-pressure reaction kettle. When the reaction conditions were as follows: catalyst dosage 101 mg, nitrobenzene 90 mg, toluene 2 mL, H2 2 MPa, reaction temperature 140°C, and reaction time 3 hours, the conversion rate of nitrobenzene was 41.8% and the selectivity of aniline was 56.8%.

Claims

1. A process for the preparation of a supported copper-based catalyst, characterized in that, The method comprises the following steps: 1) dissolving copper salt in water to obtain a copper salt solution; 2) Impregnate the metal oxide A with an equal or excess volume of the copper salt solution and dry in a constant temperature oven at 40-120 o C for 4-24 hours; after drying, the solid is calcined in a muffle furnace at 300-500 o C for 2-12 hours; and reduce the solid in a hydrogen-containing atmosphere at 200-400 o C for 1-6 hours. 3) put the solid obtained in step 2) into an organic solvent, and add another metal oxide B; heat the mixture to 100-170 o C, keep for 1-24 hours; solid-liquid separation, and the solid is a supported copper-based catalyst; the metal oxide A is one or more of Al2O3, SiO2, or TiO2; the metal oxide B is one or more of Nb2O5, CeO2, or ZrO2.

2. The preparation method according to claim 1, characterized in that: The mass ratio of copper to metal oxide A in the prepared supported copper-based catalyst is 1-10%; The mass ratio of metal oxide A to metal oxide B is 0.1-10.

3. The preparation method according to claim 1, characterized in that: The organic solvent is one or more of methanol, ethanol, hexane, heptane, octane, toluene, xylene, trimethylbenzene, ethylbenzene, acetonitrile, and 1,4-dioxane; The volume-to-mass ratio of the organic solvent to metal oxide B is 1-3 mL of organic solvent: 10-250 mg of metal oxide B.

4. The preparation method according to claim 1, characterized in that: The copper salt is one or more of copper nitrate, copper sulfate, copper chloride, and copper acetate; The molecular formula of the copper nitrate is Cu(NO3)2·xH2O, where x=0, 3, or 6; the molecular formula of the copper sulfate is CuSO4·yH2O, where y=0, 1, 3, or 5; the molecular formula of the copper chloride is CuCl2·zH2O, where z=0 or 2; and the molecular formula of the copper acetate is Cu(CH3COO)2·wH2O, where w=0 or 1; The solid-liquid separation method is centrifugation, and the supported copper-based catalyst is obtained by washing the collected solid after centrifugation.

5. The preparation method of a supported copper-based catalyst according to claim 1, characterized in that: The hydrogen-containing atmosphere is hydrogen gas or a mixture of hydrogen gas and an inert gas; the inert gas includes one or more of nitrogen, argon, and helium; and the volume fraction of hydrogen in the hydrogen-containing atmosphere is 1-100%. The heating treatment atmosphere in step 3) is one or more of hydrogen, nitrogen, argon, and helium.

6. A supported copper-based catalyst prepared by the preparation method of any one of claims 1-5.

7. Use of the supported copper-based catalyst of claim 6 in catalyzing the hydrogenation of nitrobenzene.

8. Use according to claim 7, wherein the compound is ###0002### The use specifically involves placing the supported copper-based catalyst in a high-pressure reaction kettle, adding an organic solvent and nitrobenzene, adding a reducing agent, and promoting the reaction under heating conditions.

9. The use of claim 8, characterized in that: The organic solvent is one or more of methanol, ethanol, toluene, xylene, 1,4-dioxane, and cyclohexane; The reducing agent is H2, and the pressure is 0.2-5 MPa.

10. The use of claim 8, characterized in that: The heating condition temperature is 100-160 o C; the time is 0.5-10 hours.

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