Preparation method of green and efficient copper catalyst

Abstract

The invention relates to the field of catalysts, in particular to a preparation method of a green and efficient copper catalyst. Comprising the following steps: (1) mixing basic cupric carbonate, ammonia water and water, adding ammonium salt at the same time, and preparing a copper ammonia solution as a precursor solution at room temperature; (2) mixing the precursor solution with a carrier or a carrier precursor to realize active component loading and catalyst preparation; and (3) filtering, washing, drying and roasting the mixed system in the step (2) to prepare the copper-based catalyst. According to the preparation method of the copper ammonia complexing precursor solution, preparation of the copper ammonia complexing solution at room temperature can be achieved, heating operation in the precursor preparation process is avoided, meanwhile, the nitrogen content of the system and nitrogen emission in the subsequent roasting process can be reduced by preparing the copper-based catalyst through the basic copper carbonate precursor, and efficient and green preparation of the catalyst is achieved.

Description

TECHNICAL FIELD

[0001] The application relates to the field of catalysts, in particular to a green and efficient copper catalyst preparation method. BACKGROUND

[0002] Copper-based catalysts have many advantages such as good catalytic activity, low toxicity and low price, and are widely used in organic synthesis, methanol synthesis, hydrogenation reaction, oxidation reaction, electrocatalysis and environmental protection. At present, the main preparation methods of copper-based catalysts include impregnation method, coprecipitation method, sol-gel method, chemical reduction method, spray pyrolysis method and electrodeposition method. Copper-based catalysts prepared by different methods play an important role in methanol synthesis catalyst, CO low-temperature shift catalyst, fatty acid ester hydrogenation catalyst, glycerol hydrogenolysis catalyst, nitrobenzene aniline catalyst and cyclohexanol dehydrogenation to cyclohexanone catalyst.

[0003] In the preparation process of copper-based catalysts, copper-containing precursor solution needs to be prepared. Different forms of precursor solution have a significant influence on the structure-activity relationship of the prepared catalyst. Zhang Wenzhong et al. of the Chinese Academy of Sciences Lanzhou Institute of Chemical Physics found that the copper-containing catalyst prepared by ammonia intervention has higher dispersity (Molecular Catalysis, 1993, (03), 178-185). Therefore, the copper-ammonia complex precursor solution is the mainstream precursor solution system for preparing high-dispersion copper-based catalysts. According to the form of copper source for preparing the precursor solution, there are three types of current main preparation technical paths for the copper-ammonia complex precursor solution.

[0004] 1. Metal copper source preparation path A copper-ammonia solution is prepared by oxidizing metal copper under the conditions of air and ammonia source and controlling the reaction temperature to be 40-65 DEG C (CN1768941).

[0005] 2. Copper metal salt preparation path A copper-ammonia solution is prepared by preparing copper salts such as copper nitrate, copper chloride, copper sulfate and copper acetate into an aqueous solution, and then adding ammonia water dropwise (Molecular Catalysis, 1993, (03), 178-185; CN1285407C).

[0006] 3. Malachite and other copper compounds preparation path A copper-ammonia complex solution is prepared by adding ammonia water, ammonium carbonate or ammonium bicarbonate while continuously stirring under heating conditions using copper-containing compounds such as basic copper carbonate (CN103721367A, CN104353479A, CN105251447A, CN106513004A and CN111389362A; Hydrometallurgy, 2005, 76 (1), 55-62).

[0007] It can be seen that most of the existing technologies for preparing copper ammonia complex precursor solution need heating treatment operation, especially the path of taking metallic copper and basic copper carbonate as precursors, the heating operation will accelerate the volatilization of ammonia in the system, increase the energy consumption and safety risk in the preparation process. SUMMARY

[0008] The present application provides a green and efficient copper catalyst preparation method to solve the technical problems of high energy consumption and safety risk in the preparation of copper ammonia complex precursor solution. Through the improvement of the precursor preparation method, the room temperature preparation of copper ammonia solution with a wide concentration range is realized by taking basic copper carbonate as the active component precursor, avoiding the heating operation in the preparation process of the precursor solution, and realizing the green and efficient preparation of the copper-based catalyst.

[0009] To solve the above technical problems, the technical scheme adopted by the present application is as follows: a green and efficient copper catalyst preparation method, comprising the following steps: (1) mixing basic copper carbonate, ammonia water and water, and adding ammonium salt, to prepare copper ammonia solution as precursor solution at room temperature; (2) mixing the precursor solution with the carrier or carrier precursor to realize active component loading and catalyst preparation; (3) filtering, washing, drying and calcining the mixed system of step (2) to obtain a copper-based catalyst.

[0010] As a further limitation of the technical scheme of the present application, metal additives are added after the addition of ammonium salt in step (1), and the metal additives are at least one of metal salts containing vanadium, chromium, manganese, iron, cobalt, nickel, zinc, gallium, zirconium, molybdenum, ruthenium, rhodium, palladium, silver, indium, tin, barium, tungsten, iridium, platinum, gold and lanthanum.

[0011] As a further limitation of the technical scheme of the present application, the addition amount of the metal additive is 0.001-10 times the mass of the basic copper carbonate.

[0012] As a further limitation of the technical scheme of the present application, the ammonium salt in step (1) is at least one of ammonium nitrate, ammonium chloride, ammonium sulfate, ammonium bisulfate, ammonium fluoride, ammonium iodide and ammonium bromide.

[0013] As a further limitation of the technical scheme of the present application, the mass ratio of basic copper carbonate, ammonia water and water in step (1) is 1:1-10:1-50.

[0014] As a further limitation of the technical scheme of the present application, the mass ratio of basic copper carbonate, ammonia water and water in step (1) is 1:3-5:10-20.

[0015] As a further limitation of the technical scheme of the present application, the addition amount of the ammonium salt in step (1) is 0.1-0.6 times the mass of the basic copper carbonate.

[0016] As a further limitation of the technical scheme of the application, in step (2), the mass ratio of the precursor solution and the carrier or carrier precursor is 0.1-50:1.

[0017] As a further limitation of the technical scheme of the application, in step (2), the catalyst loading method is equal-volume impregnation, excess impregnation, deposition precipitation, coprecipitation, ammonia evaporation method or sol-gel method.

[0018] As a further limitation of the technical scheme of the application, in step (2), the carrier is active alumina, molecular sieve, silica gel, activated carbon, graphene, carbon nanotube, titanium oxide, silicon carbide, pumice or diatomite; and the carrier precursor is aluminum nitrate, sodium silicate, ethyl silicate, titanium chloride or titanyl sulfate.

[0019] As a further limitation of the technical scheme of the application, in step (3), the drying temperature is -77-150 °C, the calcination temperature is 300-500 °C, and the calcination time is 1-10 h.

[0020] Preferably, in step (3), the drying temperature is -30-0 °C or 110-130 °C, the calcination temperature is 350-470 °C, and the calcination time is 2-5 h.

[0021] Compared with the prior art, the application has the following beneficial effects: The preparation method of the copper-ammonia complex precursor solution can realize the preparation of the copper-ammonia complex solution at room temperature, avoids the heating operation in the preparation process of the precursor, and can reduce the nitrogen content of the system and the nitrogen emission in the subsequent calcination process when the copper-based catalyst is prepared from the basic copper carbonate precursor, thereby realizing the efficient and green preparation of the catalyst. DETAILED DESCRIPTION

[0022] The application will be further described below in combination with specific examples. Example 1

[0023] A green and efficient copper catalyst preparation method comprises the following steps: (1) mixing basic copper carbonate, ammonia water and water in a mass ratio of 1:1:19, and adding 1 / 3 of the mass of the basic copper carbonate as ammonium nitrate to prepare a copper-ammonia solution at room temperature; (2) mixing the precursor solution with the carrier silicon oxide in a mass ratio of 15:1 to realize the loading of the active component and the preparation of the catalyst; (3) filtering, washing, drying and calcining the mixed system to obtain a copper-based catalyst, wherein the drying temperature is 110 °C, the calcination temperature is 350 °C, and the calcination time is 3 h. Example 2

[0024] A green and efficient copper catalyst preparation method comprises the following steps: (1) Mix basic copper carbonate, ammonia water and water in a mass ratio of 1:1:19, and add 1 / 3 of the mass of the basic copper carbonate as ammonium nitrate and 5% of the mass of the basic copper carbonate as ammonium molybdate as a metal additive, to prepare a copper ammonia solution with the metal molybdenum additive at room temperature; (2) Mix the precursor solution with the carrier silicon oxide in a mass ratio of 15:1 to realize one-step active component and additive loading and catalyst preparation; (3) Filter, wash, dry and calcine the mixed system to obtain the molybdenum-modified copper-based catalyst, the drying temperature is 110 °C, the calcination temperature is 350 °C, and the calcination time is 3 h. Example 3

[0025] A green and efficient copper catalyst preparation method comprises the following steps: (1) Mix basic copper carbonate, ammonia water and water in a mass ratio of 1:1:19, and add 1 / 3 of the mass of the basic copper carbonate as ammonium nitrate, to prepare a copper ammonia solution at room temperature; (2) Mix the precursor solution with the carrier silicon oxide in a mass ratio of 15:1 to realize active component loading; (3) Filter, wash, dry and calcine the mixed system to obtain the copper-based catalyst, the drying temperature is 110 °C, the calcination temperature is 350 °C, and the calcination time is 3 h; (4) After the prepared copper-based catalyst is impregnated with a 5% molybdenum acid ammonium solution of the mass of the basic copper carbonate, dry it at 110 °C for 12 h and calcine it at 350 °C for 3 h, a molybdenum-modified copper-based catalyst is obtained in steps. Example 4

[0026] A green and efficient copper catalyst preparation method comprises the following steps: (1) Mix basic copper carbonate, ammonia water and water in a mass ratio of 1:7:1, and add 1 / 3 of the mass of the basic copper carbonate as ammonium chloride, to prepare a copper ammonia solution at room temperature; (2) Mix the precursor solution with the carrier activated carbon in a mass ratio of 1:1 to realize active component loading and catalyst preparation; (3) Dry the mixed system to obtain the copper-based catalyst, the drying temperature is 140 °C, and the drying time is 8 h. Example 5

[0027] A green and efficient copper catalyst preparation method comprises the following steps: (1) Mix basic copper carbonate, ammonia water and water in a mass ratio of 1:7:1, and add 1 / 3 of the mass of the basic copper carbonate as ammonium nitrate, to prepare a copper ammonia solution at room temperature; (2) The precursor solution is mixed with the carrier activated carbon at a mass ratio of 1:1 to realize the loading of the active component and the preparation of the catalyst; (3) The mixed system is dried to prepare the copper-based catalyst, the drying temperature is 140 DEG C, and the drying time is 8 h. Example 6

[0028] A green and efficient copper catalyst preparation method comprises the following steps: (1) The basic copper carbonate, ammonia water and water are mixed uniformly at a mass ratio of 1:7:1, and the ammonium chloride with a mass of 1 / 3 of the basic copper carbonate is added, and a copper ammonia solution is prepared at room temperature, and then the ammonium molybdate with a mass of 5% of the basic copper carbonate is added, and a copper ammonia precursor mixed solution with additives is prepared; (2) The precursor solution is mixed with the carrier activated carbon at a mass ratio of 1:1 to realize the loading of the active component and the preparation of the catalyst; (3) The mixed system is dried to prepare the copper-based catalyst, the drying temperature is 140 DEG C, and the drying time is 8 h.

[0029] The copper / silicon oxide catalyst prepared in the above examples 1-3 is tested for catalytic performance, a gas phase hydrogenation process is adopted, the catalyst loading is 500 mg, the space velocity of nitrobenzene is 40 h -1 , and the concentration of nitrobenzene in the product reaches 1.0% (GC analysis method) as the test endpoint, and the catalyst performance and one-time life results are as follows: Table 1 Experimental data

[0030] The copper / carbon catalyst prepared in the above examples 4-6 is tested for protective performance, the catalyst is filled in a power pipe with a diameter of 2 cm, the bed height is 2 cm, the inlet gas is air with an ammonia content of 2.3 mg / L in the ammonia protection test, the test temperature is 20 DEG C, the relative humidity is 50%, the specific speed is 0.25 L / (min·cm 2 ), the inlet gas is air with a sulfur dioxide content of 4.6 mg / L in the sulfur dioxide protection test, the test temperature is 20 DEG C, the relative humidity is 50%, and the specific speed is 0.25 L / (min·cm 2 ). The test results are as follows: Table 2 Experimental data

[0031] The application prepares a copper ammonia precursor solution at room temperature by using auxiliary additives such as ammonium chloride, ammonium nitrate, ammonium sulfate, ammonium bisulfate, ammonium fluoride, ammonium iodide and ammonium bromide, so that a green and efficient copper-based catalyst preparation method is prepared.

Claims

1. A method for preparing a green and efficient copper catalyst, characterized in that, Includes the following steps: (1) Mix basic copper carbonate, ammonia and water, and add ammonium salt to prepare a copper ammonia solution as a precursor solution at room temperature; (2) The precursor solution is mixed with the support or the support precursor to achieve active component loading and catalyst preparation; (3) The mixture system of step (2) is filtered, washed, dried and calcined to obtain a copper-based catalyst.

2. The method for preparing a green and efficient copper catalyst according to claim 1, characterized in that, In step (1), after adding the ammonium salt, a metal additive is also added. The metal additive is at least one of the metal salts containing vanadium, chromium, manganese, iron, cobalt, nickel, zinc, gallium, zirconium, molybdenum, ruthenium, rhodium, palladium, silver, indium, tin, barium, tungsten, iridium, platinum, gold and lanthanum. The amount of metal additive added is 0.001 to 10 times the mass of basic copper carbonate.

3. The method for preparing a green and efficient copper catalyst according to claim 1, characterized in that, The ammonium salt in step (1) is at least one of ammonium nitrate, ammonium chloride, ammonium sulfate, ammonium bisulfate, ammonium fluoride, ammonium iodide and ammonium bromide.

4. The method for preparing a green and efficient copper catalyst according to claim 1, characterized in that, In step (1), the mass ratio of basic copper carbonate, ammonia and water is 1:1~10:1~50.

5. The method for preparing a green and efficient copper catalyst according to claim 1, characterized in that, In step (1), the mass ratio of basic copper carbonate, ammonia and water is 1:3~5:10~20.

6. The method for preparing a green and efficient copper catalyst according to claim 1, characterized in that, In step (1), the amount of ammonium salt added is 0.1 to 0.6 times the mass of basic copper carbonate.

7. The method for preparing a green and efficient copper catalyst according to claim 1, characterized in that, In step (2), the mass ratio of the precursor solution to the carrier or the carrier precursor is 0.1 to 50:

1.

8. The method for preparing a green and efficient copper catalyst according to claim 1, characterized in that, In step (2), the catalyst loading method is equal volume impregnation, excess impregnation, deposition precipitation, co-precipitation, ammonia stripping, or sol-gel method.

9. The method for preparing a green and efficient copper catalyst according to claim 1, characterized in that, In step (2), the carrier is activated alumina, molecular sieve, silica gel, activated carbon, graphene, carbon nanotubes, titanium dioxide, silicon carbide, pumice or diatomaceous earth; the carrier precursor is aluminum nitrate, sodium silicate, ethyl silicate, titanium chloride or titanium oxysulfate.

10. A method for preparing a green and efficient copper catalyst according to claim 1, characterized in that, The drying temperature in step (3) is -77~150 °C, the calcination temperature is 300~500 °C, and the calcination time is 1~10 h.

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