Composite copper catalyst for acetylene hydrochlorination reaction and preparation method thereof

Abstract

The invention belongs to the technical field of chemical catalysis, and provides a composite copper catalyst for acetylene hydrochlorination reaction and a preparation method thereof. The composite copper catalyst comprises a copper precursor, an alkali metal additive, a chloride additive and an activated carbon carrier, the alkali metal additive is one or more of lithium chloride, sodium chloride, potassium chloride, rubidium chloride and cesium chloride; the mass ratio of the copper precursor to the alkali metal additive to the chloride additive is (8-16): (0.8-1.5): (0.5-1.5). The composite copper-based catalyst provided by the invention can effectively improve the adsorption capacity of the active component copper, reduce the loss of copper, improve the stability of the catalyst, effectively enhance the dispersibility of the active component, improve the adsorption effect on hydrogen chloride, reduce the adsorption effect on acetylene and vinyl chloride, and reduce carbon deposition.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical catalysis, and particularly relates to a composite copper catalyst for acetylene hydrochlorination reaction and a preparation method thereof. Background Art

[0002] Polyvinyl chloride (PVC) is a polymer formed by the polymerization of vinyl chloride (VCM) monomers in the presence of initiators such as peroxides and azo compounds or under the action of light or heat according to the free radical polymerization mechanism. Because of the introduction of chlorine atoms in the macromolecule, it has surpassed polyethylene in terms of flame retardancy, transparency, folding resistance and mechanical properties. It is a product that can be processed by molding, kneading, injection molding, calendering, blow molding and other methods. Based on my country's energy structure of "rich in coal, less oil, and poor in gas", the production of VCM monomers by the carbide acetylene method has become my country's main method of producing PVC. The HgCl required for the carbide acetylene method 2 Mercury usage in catalysts accounts for 60% of the country's total mercury usage. However, with the advancement of mercury pollution prevention and control policies and the increasing depletion of mercury resources, companies that prepare PVC using the calcium carbide method will face severe challenges.

[0003] The catalysts used in the production of PVC by the calcium carbide process will gradually shift to low-mercury or even mercury-free catalysts. Currently, most of the newly developed catalysts are precious metal (Au, Pd, Pt, Rh, Ru, etc.) catalysts. Precious metal catalysts are highly active and renewable, but precious metals are expensive, and the production cost of PVC is too high, which is not conducive to large-scale and widespread application. There are also catalysts that use non-precious metals such as Cu, Zn, Bi, Sn, etc. as active components. Among them, non-precious metal copper-based catalysts have been widely studied and applied due to their excellent catalytic performance. Copper catalysts have the advantages of high activity and high vinyl chloride yield, and have great potential in the research and development of mercury-free catalysts for acetylene hydrochlorination. However, copper catalysts also have (1) Cu 2+ The substance is reduced to Cu 0 ; (2) the formation of coke deposits and (3) Cu loss.

[0004] For example, Chinese patent CN113634283B discloses a copper-based composite catalyst and method for acetylene hydrochlorination reaction, wherein the catalyst uses Schiff base pretreated activated carbon as a carrier, and carries copper-amino acid complex and co-catalytic components such as cesium chloride, barium chloride, cobalt chloride and cerium chloride. The invention first pre-treats the activated carbon with Schiff base, and prepares the copper-amino acid complex by dripping amino acid into copper chloride, and then impregnates the copper-amino acid complex and co-catalytic components into the activated carbon pre-treated with Schiff base, and dries to obtain the copper-based composite catalyst, which can be impregnated multiple times to obtain a catalyst with high metal content. The catalyst of the invention has high catalytic activity and selectivity in the acetylene hydrochlorination reaction, and the activity is almost not attenuated during long-term operation. The stability is better than that of the existing mercuric chloride catalyst, the catalyst cost is low, the preparation process is simple and pollution-free, and the acetylene conversion rate can be maintained at more than 98% and the selectivity can be maintained at more than 99.5% during long-term operation. However, the preparation process of the invention is complicated, not suitable for large-scale production, and the Schiff base raw material used is not easy to obtain.

[0005] For another example, Chinese patent CN 118371269 A provides a gold-based catalyst modified with a piperazine ligand for acetylene hydrochlorination reaction, and its preparation method and application, which relates to the field of chemical catalysis technology. The gold-based catalyst provided by the invention includes a gold precursor, a piperazine ligand, and a carbon carrier. The gold-based catalyst obtained by the invention has good dispersibility of the active component, and also enhances the adsorption of hydrogen chloride by the active component, delays the deposition of carbon deposits, and has high activity and good stability. The acetylene conversion rate is greater than 81.6%, and the vinyl chloride selectivity is greater than 99.2%. However, the precious metals used in the invention are relatively expensive, which is not conducive to large-scale and widespread application.

[0006] Therefore, how to use low-cost, easily available catalysts to anchor active components, improve the dispersibility of active components, and reduce the loss of active components is the focus of research. Summary of the invention

[0007] In order to overcome the disadvantages of existing copper-based catalysts such as high cost, poor stability and low activity, the object of the present invention is to provide a composite copper catalyst for acetylene hydrochlorination reaction and a preparation method thereof. The copper catalyst of the present invention is prepared by a step-by-step impregnation method combined with a carbon thermal shock method, which can achieve high dispersibility of the active component copper, while reducing the loss of the active component, improving the stability of the copper catalyst and extending the life of the catalyst.

[0008] The invention provides a composite copper catalyst for acetylene hydrochlorination reaction, characterized in that the composite copper catalyst comprises a copper precursor, an alkali metal auxiliary agent, a chloride auxiliary agent and an activated carbon carrier.

[0009] Preferably, the alkali metal auxiliary agent is one or more of lithium chloride, sodium chloride, potassium chloride, rubidium chloride and cesium chloride; more preferably, the alkali metal auxiliary agent is at least one of sodium chloride and potassium chloride.

[0010] Preferably, the mass ratio of the copper precursor to the alkali metal additive is 8-16:0.8-1.5.

[0011] Preferably, the mass ratio of the copper precursor to the alkali metal additive and the chloride additive is 8-16:0.8-1.5:0.5-1.5.

[0012] Preferably, the composite copper catalyst for acetylene hydrochlorination reaction comprises, by weight, 0.1-20 parts of copper precursor, 0.1-8 parts of alkali metal additive, 0.1-3 parts of chloride additive per 100 parts of the composite copper catalyst, and the balance is activated carbon carrier.

[0013] Preferably, the composite copper catalyst comprises 5-15 parts of copper precursor, 1-5 parts of alkali metal additive, 1-2.5 parts of chloride additive per 100 parts, and the balance is activated carbon carrier.

[0014] Preferably, the copper precursor is CuCl 2 , Cu 3 (PO 4 ) 2 、Cu(NO 3 ) 2 ,CuSO 4 , (CH 3 COO 2 Cu; further preferably, the copper precursor is CuCl 2 , Cu 3 (PO 4 ) 2 At least one of .

[0015] Preferably, the chloride auxiliary agent is one or more of zinc chloride, barium chloride, cerium chloride and lanthanum chloride; further preferably, the chloride auxiliary agent is at least one of zinc chloride and barium chloride.

[0016] Preferably, the activated carbon carrier is washed with a strong acid; preferably, the strong acid is one or more of hydrochloric acid, nitric acid and sulfuric acid.

[0017] The present invention also provides a method for preparing a composite copper catalyst for acetylene hydrochlorination reaction, comprising the following steps:

[0018] (1) preparing a solution: dissolving a copper precursor and an alkali metal additive in a solvent according to a ratio to prepare a solution A;

[0019] (2) stirring and mixing: mixing solution A with the activated carbon support under stirring, impregnating, and drying to obtain the Cu-1 catalyst;

[0020] (3) Prepare solution: dissolve the chloride additive in the solvent according to the ratio to prepare solution B.

[0021] (4) Impregnation and drying: adding solution B dropwise onto the Cu-1 catalyst obtained in step (2), stirring, impregnating, and drying to obtain a Cu-2 catalyst;

[0022] (5) Calcination and carbonization: The Cu-2 catalyst obtained in step (4) is carbonized to finally obtain a composite copper catalyst.

[0023] Preferably, the impregnation in step (2) and step (4) is carried out at 25-30° C. for 5-6 hours.

[0024] Preferably, the drying in step (2) and step (4) is carried out at 110-120° C. for 12-14 hours.

[0025] Preferably, the carbonization in step (5) is carried out under the protection of protective gas, at a temperature of 450-500° C., and at a heating rate of 20° C. / min for 2 h;

[0026] Preferably, the protective gas is one of argon, nitrogen and helium; more preferably argon.

[0027] The present invention also provides application of the composite copper catalyst in acetylene hydrochlorination reaction.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The copper-based catalyst prepared by the present invention using a step-by-step impregnation method combined with a carbon thermal shock method can effectively improve the adsorption capacity of the active component copper, reduce copper loss, improve the stability of the catalyst, effectively enhance the dispersibility of the active component, improve the adsorption of hydrogen chloride, reduce the adsorption of acetylene and vinyl chloride, and reduce carbon deposition. DETAILED DESCRIPTION

[0030] The technical scheme of the present invention is clearly and completely described below with specific implementation methods. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention. The materials, reagents, etc. used, if not otherwise specified, are reagents and materials available from commercial sources.

[0031] Example 1 A composite copper catalyst for acetylene hydrochlorination

[0032] The preparation method is as follows:

[0033] (1) Weigh 16 g of CuCl 2 , 1.5 g of potassium chloride, and 40 mL of deionized water, stir well to obtain solution A.

[0034] (2) Weigh 27.8 g of activated carbon, add the obtained solution A dropwise onto the activated carbon carrier washed with hydrochloric acid at 25°C, stir it evenly with a glass rod, immerse it at 25°C for 5 h, and finally dry it at 110°C for 12 h to obtain Cu-1 catalyst.

[0035] (3) Weigh 0.9 g of zinc chloride and 40 mL of deionized water, stir well to obtain solution B.

[0036] (4) At 25°C, the obtained solution B was added dropwise onto the Cu-1 catalyst, stirred evenly with a glass rod, immersed at 25°C for 5 h, and finally dried at 110°C for 12 h to obtain the Cu-2 catalyst.

[0037] (5) The obtained Cu-2 catalyst was carbonized at 500°C for 2 h under an argon atmosphere with a heating rate of 20°C / min to obtain the final composite copper-based catalyst.

[0038] Example 2 A composite copper catalyst for acetylene hydrochlorination

[0039] The preparation method is as follows:

[0040] (1) Weigh 8 g of CuCl 2 , 0.8 g of potassium chloride, and 40 mL of deionized water, stir well to obtain solution A.

[0041] (2) Weigh 27.8 g of activated carbon, add the obtained solution A dropwise onto the activated carbon carrier washed with hydrochloric acid at 25°C, stir it evenly with a glass rod, immerse it at 25°C for 5 h, and finally dry it at 110°C for 12 h to obtain Cu-1 catalyst.

[0042] (3) Weigh 0.5 g of zinc chloride and 40 mL of deionized water, stir well to obtain solution B.

[0043] (4) At 25°C, the obtained solution B was added dropwise onto the Cu-1 catalyst, stirred evenly with a glass rod, immersed at 25°C for 5 h, and finally dried at 110°C for 12 h to obtain the Cu-2 catalyst.

[0044] (5) The obtained Cu-2 catalyst was carbonized at 500°C for 2 h under an argon atmosphere with a heating rate of 20°C / min to obtain the final composite copper-based catalyst.

[0045] Example 3 A composite copper catalyst for acetylene hydrochlorination

[0046] The preparation method is as follows:

[0047] (1) Weigh 16 g of CuCl 2 , 1.5 g of potassium chloride, and 40 mL of deionized water, stir well to obtain solution A.

[0048] (2) Weigh 27.8 g of activated carbon, add the obtained solution A dropwise onto the activated carbon carrier washed with hydrochloric acid at 25°C, stir it evenly with a glass rod, immerse it at 25°C for 5 h, and finally dry it at 110°C for 12 h to obtain Cu-1 catalyst.

[0049] (3) Weigh 1.5 g of zinc chloride and 40 mL of deionized water, stir well to obtain solution B.

[0050] (4) At 25°C, the obtained solution B was added dropwise onto the Cu-1 catalyst, stirred evenly with a glass rod, immersed at 25°C for 5 h, and finally dried at 110°C for 12 h to obtain the Cu-2 catalyst.

[0051] (5) The obtained Cu-2 catalyst was carbonized at 500° C. for 2 h under an argon atmosphere with a heating rate of 20° C. / min to obtain the final composite copper-based catalyst.

[0052] Example 4 A composite copper catalyst for acetylene hydrochlorination

[0053] The preparation method is as follows:

[0054] (1) Weigh 16 g of Cu 3 (PO 4 ) 2 , 1.5 g of sodium chloride, and 40 mL of deionized water, stir well to obtain solution A.

[0055] (2) Weigh 27.8 g of activated carbon, add the obtained solution A dropwise onto the activated carbon carrier washed with hydrochloric acid at 25°C, stir it evenly with a glass rod, immerse it at 25°C for 5 h, and finally dry it at 110°C for 12 h to obtain Cu-1 catalyst.

[0056] (3) Weigh 0.9 g of zinc chloride and 40 mL of deionized water, stir well, and obtain solution B.

[0057] (4) At 25°C, the obtained solution B was added dropwise onto the Cu-1 catalyst, stirred evenly with a glass rod, immersed at 25°C for 5 h, and finally dried at 110°C for 12 h to obtain the Cu-2 catalyst.

[0058] (5) The obtained Cu-2 catalyst was carbonized at 500° C. for 2 h under an argon atmosphere with a heating rate of 20° C. / min to obtain the final composite copper-based catalyst.

[0059] Example 5 A composite copper catalyst for acetylene hydrochlorination

[0060] The preparation method is as follows:

[0061] (1) Weigh 16 g of Cu 3 (PO 4 ) 2 , 1.5 g of sodium chloride, and 40 mL of deionized water, stir well to obtain solution A.

[0062] (2) Weigh 27.8 g of activated carbon, add the obtained solution A dropwise onto the activated carbon carrier washed with hydrochloric acid at 25°C, stir it evenly with a glass rod, immerse it at 25°C for 5 h, and finally dry it at 110°C for 12 h to obtain Cu-1 catalyst.

[0063] (3) Weigh 0.9 g of barium chloride and 40 mL of deionized water, stir well, and obtain solution B.

[0064] (4) At 25°C, the obtained solution B was added dropwise onto the Cu-1 catalyst, stirred evenly with a glass rod, immersed at 25°C for 5 h, and finally dried at 110°C for 12 h to obtain the Cu-2 catalyst.

[0065] (5) The obtained Cu-2 catalyst was carbonized at 500°C for 2 h under an argon atmosphere with a heating rate of 20°C / min to obtain the final composite copper-based catalyst.

[0066] Example 6 A composite copper catalyst for acetylene hydrochlorination

[0067] The preparation method is as follows:

[0068] (1) Weigh 16 g of Cu 3 (PO 4 ) 2 , 1.5 g of potassium chloride, and 40 mL of deionized water, stir well to obtain solution A.

[0069] (2) Weigh 27.8 g of activated carbon, add the obtained solution A dropwise onto the activated carbon carrier washed with hydrochloric acid at 25°C, stir it evenly with a glass rod, immerse it at 25°C for 5 h, and finally dry it at 110°C for 12 h to obtain Cu-1 catalyst.

[0070] (3) Weigh 1.5 g of zinc chloride and 40 mL of deionized water, stir well, and obtain solution B.

[0071] (4) At 25°C, the obtained solution B was added dropwise onto the Cu-1 catalyst, stirred evenly with a glass rod, immersed at 25°C for 5 h, and finally dried at 110°C for 12 h to obtain the Cu-2 catalyst.

[0072] (5) The obtained Cu-2 catalyst was carbonized at 500°C for 2 h under an argon atmosphere with a heating rate of 20°C / min to obtain the final composite copper-based catalyst.

[0073] Comparative Example 1 A composite copper-based catalyst was prepared according to the solution of Example 3 of patent CN113634283B, as follows:

[0074] The columnar coal-based activated carbon pretreated with salicylaldehyde aniline was used as a carrier to load copper-glycine complex and cesium chloride. The mass content of copper in the catalyst was 20%, and the mass content of cesium chloride was 5.26%.

[0075] First, 10g of columnar coal-based activated carbon was washed several times with tap water to remove surface impurities and ash, and then the activated carbon was slowly added to 20mL of ethanol solution of salicylaldehyde condensation aniline with a volume concentration of 10%, immersed at room temperature for 24h, and finally dried at 80℃ in a blast drying oven to obtain columnar coal-based activated carbon pretreated with salicylaldehyde condensation aniline. 2.10g (15.6mmol) of copper chloride was dissolved in 5mL of deionized water, and then 5mL of 3.12mol / L glycine aqueous solution was added dropwise, wherein the molar ratio of copper chloride to glycine was 1:1, to obtain a copper-glycine complex solution; 0.27g of cesium chloride was dissolved in 2.5mL of deionized water, added to the copper-glycine complex solution, mixed evenly, and then 5.26g of columnar coal-based activated carbon pretreated with salicylaldehyde condensation aniline was added, immersed at room temperature for 8h, placed in a blast drying oven at 100℃ for drying, and the catalyst was obtained after cooling. The catalyst impregnated once was impregnated for the second time, that is, 2.10 g (15.6 mmol) of copper chloride was dissolved in 5 mL of deionized water, and then 5 mL of 3.12 mol / L glycine aqueous solution was added dropwise to obtain a copper-glycine complex solution; then 0.27 g of cesium chloride was dissolved in 2.5 mL of deionized water, added to the copper-glycine complex solution, mixed evenly, and then the catalyst impregnated once was added. After impregnation at room temperature for 8 hours, it was placed in a forced air drying oven and dried at 100° C. to obtain a copper-based composite catalyst.

[0076] Comparative Example 2 A composite copper catalyst for acetylene hydrochlorination

[0077] The preparation method is as follows:

[0078] (1) Weigh 5 g of CuCl 2 , 2 g of potassium chloride, and 40 mL of deionized water, stir well to obtain solution A.

[0079] (2) Weigh 27.8 g of activated carbon, add the obtained solution A dropwise onto the activated carbon carrier washed with strong acid at 25°C, stir it evenly with a glass rod, immerse it at 25°C for 5 h, and finally dry it at 110°C for 12 h to obtain Cu-1 catalyst.

[0080] (3) Weigh 2 g of zinc chloride and 40 mL of deionized water, stir well, and obtain solution B.

[0081] (4) At 25°C, the obtained solution B was added dropwise onto the Cu-1 catalyst, stirred evenly with a glass rod, immersed at 25°C for 5 h, and finally dried at 110°C for 12 h to obtain the Cu-2 catalyst.

[0082] (5) The obtained Cu-2 catalyst was carbonized at 500°C for 2 h under an argon atmosphere with a heating rate of 20°C / min to obtain the final composite copper-based catalyst.

[0083] Comparative Example 3 A composite copper catalyst for acetylene hydrochlorination

[0084] The preparation method is as follows:

[0085] The only difference from Example 1 is that step (5) is removed, and the remaining steps are the same as Example 1.

[0086] Effect Experiment

[0087] In order to solve the above technical problems, the present invention adopts the following technical solution: the catalyst is applied to a fixed bed reactor to carry out acetylene hydrochlorination reaction under the following conditions: the reaction gas is nitrogen, acetylene and hydrogen chloride, wherein the volume ratio of acetylene to hydrogen chloride is 1:1-2, and the acetylene space velocity is 30-300h -1 , the reaction temperature is 150-250°C. Catalyst evaluation is shown in Table 1.

[0088] Table 1

[0089]

[0090]

[0091] The non-precious metal catalyst prepared in the embodiment of the present application has a high acetylene conversion rate in the acetylene hydrochlorination reaction. -1 Under the conditions of acetylene space velocity, the acetylene conversion rate within 72 hours was greater than 90%, and the vinyl chloride selectivity was greater than 99%, both of which were better than the control example and had better stability and service life.

[0092] The above description is only a preferred embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any improvement or replacement made by a person familiar with the art within the technical scope disclosed in the present invention shall fall within the protection scope of the present invention.

Claims

1. A composite copper catalyst for acetylene hydrochlorination, characterized in that: The composite copper catalyst comprises a copper precursor, an alkali metal auxiliary agent, a chloride auxiliary agent and an activated carbon carrier; the alkali metal auxiliary agent is one or more of lithium chloride, sodium chloride, potassium chloride, rubidium chloride and cesium chloride.

2. The composite copper catalyst according to claim 1, characterized in that The copper precursor is at least one of CuCl2, Cu3(PO4)2, Cu(NO3)2, CuSO4 and (CH3COO)2Cu.

3. The composite copper catalyst according to claim 1, characterized in that The chloride auxiliary agent is one or more of zinc chloride, barium chloride, cerium chloride and lanthanum chloride.

4. The composite copper catalyst according to claim 1, characterized in that The mass ratio of the copper precursor, the alkali metal auxiliary agent and the chloride auxiliary agent is 8-16:0.8-1.5:0.5-1.

5.

5. The composite copper catalyst according to claim 1, characterized in that The copper precursor is CuCl2 or Cu3(PO4)2, the alkali metal auxiliary agent is sodium chloride or potassium chloride, and the chloride auxiliary agent is zinc chloride or barium chloride.

6. The method for preparing the composite copper catalyst according to any one of claims 1 to 5, characterized in that: The steps include: (1) preparing a solution: dissolving a copper precursor and an alkali metal additive in a solvent according to a ratio to prepare a solution A; (2) stirring and mixing: mixing solution A with the activated carbon support under stirring, impregnating, and drying to obtain the Cu-1 catalyst; (3) preparing a solution: dissolving the chloride auxiliary agent in a solvent according to a ratio to prepare a solution B; (4) Impregnation and drying: adding solution B dropwise onto the Cu-1 catalyst obtained in step (2), stirring, impregnating, and drying to obtain a Cu-2 catalyst; (5) Calcination and carbonization: The Cu-2 catalyst obtained in step (4) is carbonized to finally obtain a composite copper catalyst.

7. The preparation method according to claim 6, characterized in that: The impregnation in step (2) and step (4) is carried out at 25-30° C. for 5-6 hours.

8. The preparation method according to claim 6, characterized in that: The drying in step (2) and step (4) is carried out at 110-120° C. for 12-14 hours.

9. The preparation method according to claim 6, characterized in that: The carbonization in step (5) needs to be carried out under the protection of an inert gas. The carbonization is carried out by heating the temperature to 450-500°C at a rate of 20°C / min. The carbonization time is 2h. The inert gas is one of argon, nitrogen or helium.

10. Use of the composite copper catalyst according to any one of claims 1 to 5 or the composite copper catalyst prepared by the preparation method according to any one of claims 6 to 9 in acetylene hydrochlorination reaction.

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