Non-noble metal copper-based catalyst as well as preparation method and application thereof

Abstract

The invention discloses a non-noble metal copper-based catalyst as well as a preparation method and application thereof. The preparation method comprises the following steps: dissolving a copper source and a second metal source in a solvent to obtain a precursor prefabricated solution, dropwise adding an alkaline solution to adjust the pH value of the precursor prefabricated solution to 7-13, keeping for 4-12 hours in an oil bath environment of 60-100 DEG C, aging, filtering, washing and drying to obtain a solid precursor; and putting the obtained solid precursor into a muffle furnace, heating to 200-800 DEG C in an air atmosphere, and roasting for 1-9 hours to obtain the non-noble metal copper-based catalyst. Wherein the second metal source is an aluminum source, a magnesium source, a zinc source, a zirconium source or a cobalt source; the catalyst can realize complete conversion (100%) of acetylene and selectivity of more than 95% of ethylene at a low temperature (180 DEG C) and a high space velocity (18000 ml / gcat / h), does not inactivate after more than 150 h under repeated cycle tests, and has important significance for industrial production.

Description

Technical Field

[0001] The invention relates to a non-noble metal copper-based catalyst and a preparation method thereof, as well as application of the catalyst in acetylene selective hydrogenation reaction. Background Art

[0002] Ethylene is a key monomer for the manufacture of polymers and fine chemicals, and is mainly derived from the steam cracking of liquefied petroleum gas. However, acetylene impurities are inevitably produced during the cracking of liquefied petroleum gas to produce ethylene, which can irreversibly poison the Ziegler-Natta catalyst used for ethylene polymerization and greatly reduce the quality of the target polymer. Therefore, acetylene impurities need to be reduced to <5 ppm in the ethylene stream (Acs Catalysis, 2012, 2(8): 1773-1786.).

[0003] Selective hydrogenation of acetylene provides an economically viable solution for the separation of ethylene and acetylene in industrial operations. In this industry, palladium-based catalysts are widely used due to their high activity, among which PdAg / Al2O3 dominates in industrial ethylene production (Applied Catalysis A: General, 2011, 400 (1-2): 14-24.). This catalyst changes the surface electronic structure of palladium to adjust C=C adsorption, thereby significantly improving the selectivity of ethylene. However, the performance at lower temperatures is still not ideal (selectivity of 55% and conversion of 90% at 100°C), and both Pd and Ag will incur a lot of costs (Journal of the American Chemical Society, 2021, 143 (16): 6281-6292.). The patent documents currently applied for are mainly concentrated in the field of precious metal catalysts (authorized CN114733569B, CN112191244B, CN113976153B). In view of this, as an economical alternative, copper-based catalysts have attracted widespread attention due to their significant selectivity and less olefin perhydrogenation side reactions (Journal of the American Chemical Society, 2010, 132 (12): 4321-4327.). At present, the research on acetylene semi-hydrogenation reaction catalysts is mainly concentrated on precious metal-based catalysts, while the research on non-precious metal catalysts is relatively small, and there are even fewer catalysts with excellent activity, selectivity and stability.

[0004] The invention discloses a non-precious metal copper-based catalyst, which can achieve complete conversion of acetylene and >95% ethylene selectivity at a low temperature of 180°C, and has no deactivation for more than 150 hours under repeated cycle tests, which is of great significance for industrial production. Summary of the invention

[0005] The present invention aims to provide a non-precious metal copper-based catalyst and a preparation method and application thereof. The catalyst can be used for acetylene semi-hydrogenation, and can greatly improve the stability of the copper-based catalyst in the acetylene selective hydrogenation reaction while maintaining high conversion rate and high selectivity.

[0006] The technical solution of the present invention is as follows:

[0007] A method for preparing a non-precious metal copper-based catalyst comprises:

[0008] Dissolve a copper source and a second metal source in a solvent to obtain a precursor pre-solution, add an alkaline solution dropwise to adjust the pH of the precursor pre-solution to 7-13, then age it in an oil bath at 60-100° C. for 4-12 hours, filter and wash it, and dry it (60-100° C., 6-24 hours) to obtain a solid precursor; place the obtained solid precursor in a muffle furnace, heat it to 200-800° C. in an air atmosphere, and calcine it for 1-9 hours to obtain the non-precious metal copper-based catalyst;

[0009] in,

[0010] The molar ratio of the copper source to the second metal source is 0.1 to 8:1;

[0011] The copper source is selected from one or more of cupric chloride, cuprous chloride, cupric sulfate, cupric nitrate, cupric carbonate, basic cupric carbonate, and cupric acetate;

[0012] The second metal source is an aluminum source, a magnesium source, a zinc source, a zirconium source or a cobalt source, etc. Specifically, the aluminum source is selected from one or more of aluminum nitrate, aluminum sulfate, aluminum chloride, aluminum carbonate, ammonium aluminum sulfate, potassium aluminum sulfate, and aluminum acetate; the magnesium source is selected from one or more of magnesium nitrate, magnesium sulfate, magnesium chloride, magnesium carbonate, and magnesium acetate; the zinc source is selected from one or more of zinc nitrate, zinc sulfate, zinc chloride, and zinc acetate; the zirconium source is selected from one or more of zirconium nitrate, zirconium sulfate, zirconium chloride, and zirconium acetate; the cobalt source is selected from one or more of cobalt nitrate, cobalt sulfate, cobalt chloride, and cobalt acetate;

[0013] The solvent is selected from one or more of deionized water, anhydrous methanol, ethylene glycol, acetone, DMF, chloroform, toluene, and anhydrous ethanol;

[0014] The alkaline solution is obtained by dissolving an alkaline substance in water, and the alkaline substance is selected from one or more of sodium bicarbonate, sodium carbonate, sodium sulfite, sodium hydroxide, sodium acetate, sodium silicate, sodium hypochlorite, sodium sulfide, ammonium bicarbonate, and ammonium sulfide.

[0015] The invention relates to a non-noble metal copper-based catalyst prepared by the preparation method.

[0016] The non-precious metal copper-based catalyst of the present invention can be used for the selective hydrogenation reaction of acetylene. Before the reaction, the catalyst is first reduced with hydrogen, the reduction temperature is 100-500° C., and the time is 1-8 hours. Then the reduced catalyst is used for the selective hydrogenation reaction of acetylene, and the reaction conditions are: temperature 80-240° C., pressure 0.1-1 MPa (preferably 0.1-0.3 MPa, more preferably normal pressure), space velocity 10000-100000 mL·g -1 ·h -1 ; The volume ratio of hydrogen to acetylene is 1 to 2:1.

[0017] The technical principles of the present invention include:

[0018] The present invention adopts a simple one-step precipitation method to prepare a non-precious metal copper-based catalyst. In traditional catalyst systems, metals are usually loaded on metal oxides, while in the catalyst system of the present application, metal Cu is used as the substrate and metal oxide MO X (M=Al, Zn, Mg, Zr, Co, etc.) is loaded onto metal Cu as a load, which is the reverse direction and is recorded as MO X @Cu catalytic system. This invention is the first to apply the reverse catalyst concept to develop acetylene semi-hydrogenation catalysts and achieve excellent activity and stability.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present invention provides a novel non-precious metal copper-based catalyst, and uses it for acetylene semi-hydrogenation reaction. The catalyst of the present invention exhibits high acetylene conversion rate, high ethylene selectivity and ultra-high stability. At the same time, the reaction temperature is low, the preparation process is simple, the synthesis is fast, the cost is low, and it is safe and efficient, and has great industrial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 : Test results of acetylene conversion (a) and ethylene selectivity (b) of non-precious metal copper-based catalysts in Examples 1-4; Reaction conditions: C2H2 / H2=1 / 2, space velocity of 18000ml / g cat / h, normal pressure, reaction temperature 140-200℃.

[0022] Figure 2 : Example 1 Stability diagram of non-precious metal copper-based catalyst; Reaction conditions: C2H2 / H2=1 / 2, reaction temperature of 180°C, space velocity of 18000ml / g cat / h, normal pressure.

[0023] Figure 3 : X-ray photoelectron spectroscopy (XPS) of the non-precious metal copper-based catalyst of Example 1.

[0024] Figure 4 : X-ray diffraction (XRD) pattern of the non-precious metal copper-based catalyst of Example 1.

[0025] Figure 5 : Transmission electron microscopy (TEM) image of the non-precious metal copper-based catalyst of Example 1.

[0026] Figure 6 : Scanning electron microscope (SEM) image of the non-precious metal copper-based catalyst of Example 1.

[0027] Figure 7 : Example 5-6 Test results of acetylene conversion (a) and ethylene selectivity (b) of non-precious metal copper-based catalysts; Reaction conditions: C2H2 / H2=1 / 2, space velocity of 18000ml / g cat / h, normal pressure, reaction temperature 80-200℃.

[0028] Figure 8 : Schematic diagram of the structural comparison between the catalyst of the present invention and the traditional catalyst. DETAILED DESCRIPTION

[0029] The present invention is further described below by means of specific embodiments, but the protection scope of the present invention is not limited thereto.

[0030] Example 1

[0031] Dissolve 0.644g Cu(NO3)3·3H2O and 2.000g Al(NO3)3·9H2O in 50mL deionized water to prepare a precursor solution. Add the prepared NaOH and Na2CO3 mixed alkali solution (wherein the mass fraction of NaOH is 3% and the mass fraction of Na2CO3 is 2%, the same below) dropwise to the precursor solution and maintain pH=8, then oil bath at 80°C for 6h, then filter and wash, transfer the solid residue to a drying oven and dry at 80°C for 6h to obtain a solid precursor. Place the precursor solid in a muffle furnace and calcine at 350°C for 5h to obtain a non-precious copper-based catalyst. Reduce the catalyst at 200°C in a hydrogen atmosphere for 3h, and then use it for the selective hydrogenation of acetylene. The results are shown in Table 1.

[0032] Example 2

[0033] 1.288g Cu(NO3)3·3H2O and 2.000g Al(NO3)3·9H2O were dissolved in 50mL deionized water to prepare a precursor solution. The prepared mixed alkaline solution of NaOH and Na2CO3 was added dropwise to the precursor solution and the pH was maintained at 8, followed by oil bath at 90°C for 7h, followed by filtration and washing, and the solid residue was transferred to a drying oven and dried at 80°C for 6h to obtain a solid precursor. The precursor solid was placed in a muffle furnace and calcined at 450°C for 4h to obtain a non-precious copper-based catalyst. The catalyst was reduced at 180°C in a hydrogen atmosphere for 4h and then used for the selective hydrogenation of acetylene. The results are shown in Table 1.

[0034] Example 3

[0035] 3.863g Cu(NO3)3·3H2O and 2.000g Al(NO3)3·9H2O were dissolved in 50mL deionized water to prepare a precursor solution. The prepared mixed alkaline solution of NaOH and Na2CO3 was added dropwise to the precursor solution and the pH was maintained at 9, followed by oil bath at 85°C for 7h, followed by filtration and washing, and the solid residue was transferred to a drying oven and dried at 80°C for 6h to obtain a solid precursor. The precursor solid was placed in a muffle furnace and calcined at 550°C for 3h to obtain a non-precious copper-based catalyst. The catalyst was reduced at 250°C in a hydrogen atmosphere for 5h and then used for the selective hydrogenation of acetylene. The results are shown in Table 1.

[0036] Example 4

[0037] Dissolve 6.438g Cu(NO3)3·3H2O and 2.000g Al(NO3)3·9H2O in 50mL deionized water to prepare a precursor solution. Add the prepared NaOH and Na2CO3 mixed alkali solution dropwise to the precursor solution and maintain pH = 10, then oil bath at 90°C for 7h, filter and wash, transfer the solid residue to a drying oven and dry at 80°C for 6h to obtain a solid precursor. Place the precursor solid in a muffle furnace and calcine at 650°C for 3h to obtain a non-precious copper-based catalyst. Reduce the catalyst at 300°C in a hydrogen atmosphere for 4h and then use it for selective hydrogenation of acetylene. The results are shown in Table 1.

[0038] Example 5

[0039] Dissolve 6.438g Cu(NO3)3·3H2O and 2.000g Zn(NO3)3·9H2O in 50mL deionized water to prepare a precursor solution. Add the prepared NaOH and Na2CO3 mixed alkali solution dropwise to the precursor solution and maintain pH=9, then oil bath at 90°C for 8h, filter and wash, transfer the solid residue to a drying oven and dry at 80°C for 6h to obtain a solid precursor. Place the precursor solid in a muffle furnace and calcine at 400°C for 4h to obtain a non-precious copper-based catalyst. Reduce the catalyst at 250°C in a hydrogen atmosphere for 4h and then use it for the selective hydrogenation of acetylene. The results are shown in Table 1.

[0040] Example 6

[0041] Dissolve 6.438g Cu(NO3)3·3H2O and 2.000g Mg(NO3)3·9H2O in 50mL deionized water to prepare a precursor solution. Add the prepared NaOH and Na2CO3 mixed alkali solution dropwise to the precursor solution and maintain pH=9, then oil bath at 90°C for 8h, filter and wash, transfer the solid residue to a drying oven and dry at 80°C for 6h to obtain a solid precursor. Place the precursor solid in a muffle furnace and calcine at 400°C for 4h to obtain a non-precious copper-based catalyst. Reduce the catalyst at 250°C in a hydrogen atmosphere for 4h and then use it for selective hydrogenation of acetylene. The results are shown in Table 1.

[0042] Table 1 Evaluation results of acetylene selective hydrogenation reaction over non-precious metal copper-based catalysts

[0043]

[0044] Reaction conditions: C2H2 / H2=1 / 2, reaction temperature 180°C, space velocity 18000ml / g cat / h, normal pressure.

Claims

1. A method for preparing a non-precious metal copper-based catalyst, characterized in that: The preparation method comprises: Dissolve a copper source and a second metal source in a solvent to obtain a precursor preformed solution, add an alkaline solution dropwise to adjust the pH of the precursor preformed solution to 7-13, then age it in an oil bath environment at 60-100° C. for 4-12 hours, filter, wash, and dry to obtain a solid precursor; place the obtained solid precursor in a muffle furnace, heat it to 200-800° C. in an air atmosphere, and calcine it for 1-9 hours to obtain the non-precious metal copper-based catalyst; in, The second metal source is an aluminum source, a magnesium source, a zinc source, a zirconium source or a cobalt source.

2. The method for preparing a non-precious metal copper-based catalyst according to claim 1, characterized in that: The molar ratio of the copper source to the second metal source is 0.1 to 8:

1.

3. The method for preparing a non-precious metal copper-based catalyst according to claim 1, characterized in that: The copper source is selected from one or more of cupric chloride, cuprous chloride, cupric sulfate, cupric nitrate, cupric carbonate, basic cupric carbonate and cupric acetate.

4. The method for preparing a non-precious metal copper-based catalyst according to claim 1, characterized in that: In the second metal source, the aluminum source is selected from one or more of aluminum nitrate, aluminum sulfate, aluminum chloride, aluminum carbonate, ammonium aluminum sulfate, potassium aluminum sulfate, and aluminum acetate; the magnesium source is selected from one or more of magnesium nitrate, magnesium sulfate, magnesium chloride, magnesium carbonate, and magnesium acetate; the zinc source is selected from one or more of zinc nitrate, zinc sulfate, zinc chloride, and zinc acetate; the zirconium source is selected from one or more of zirconium nitrate, zirconium sulfate, zirconium chloride, and zirconium acetate; the cobalt source is selected from one or more of cobalt nitrate, cobalt sulfate, cobalt chloride, and cobalt acetate.

5. The method for preparing a non-precious metal copper-based catalyst according to claim 1, characterized in that: The solvent is selected from one or more of deionized water, anhydrous methanol, ethylene glycol, acetone, DMF, chloroform, toluene, and anhydrous ethanol.

6. The method for preparing a non-precious metal copper-based catalyst according to claim 1, characterized in that: The alkaline solution is obtained by dissolving an alkaline substance in water, and the alkaline substance is selected from one or more of sodium bicarbonate, sodium carbonate, sodium sulfite, sodium hydroxide, sodium acetate, sodium silicate, sodium hypochlorite, sodium sulfide, ammonium bicarbonate, and ammonium sulfide.

7. A non-precious metal copper-based catalyst prepared by the preparation method according to any one of claims 1 to 6.

8. Use of the non-precious metal copper-based catalyst as claimed in claim 7 in the selective hydrogenation reaction of acetylene.

9. The use according to claim 8, characterized in that The application method is as follows: Before the reaction, the catalyst is first reduced with hydrogen at a reduction temperature of 100-500°C and a time of 1-8h; the reduced catalyst is then used for the selective hydrogenation of acetylene at a temperature of 80-240°C, a pressure of 0.1-1MPa, and a space velocity of 10000-100000mL·g -1 ·h -1 ; The volume ratio of hydrogen to acetylene is 1 to 2:1.

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