Multi-component composite copper catalyst as well as preparation method and application thereof

Abstract

The invention discloses a multi-element composite copper catalyst and a preparation method and application thereof, the multi-element composite copper catalyst is represented as CuXYZ / AC, AC is active carbon as a carrier, Cu is a copper precursor loaded on the active carbon, X is an auxiliary agent, Y is non-noble metal chloride, and Z is a chelating agent. According to the multi-component composite copper catalyst provided by the invention, through the synergistic effect of multiple components, on one hand, the valence state of copper is stabilized and Cu < 2 + > is prevented from being reduced to Cu through a complex generated by reaction of the auxiliary agent and the copper precursor, and the non-noble metal chloride can increase the density of electron cloud around the copper precursor, so that the hydrogen chloride adsorption effect is enhanced. Besides, the chelating agent is introduced to enhance the effect between the copper precursor and the activated carbon carrier, so that the loss of the copper precursor is inhibited, the atomic-scale dispersion effect is achieved through microwave-assisted impregnation in the preparation process, and the stability of the catalyst is further enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts, and in particular to a multi-component composite copper catalyst and a preparation method and application thereof. Background Art

[0002] Polyvinyl chloride (PVC) is an indispensable general-purpose resin material used in industry, agriculture, construction, and technology. The calcium carbide process has become the mainstream process for producing PVC. Currently, the industrial calcium carbide process primarily relies on activated carbon-supported mercuric chloride as a catalyst. However, the high volatility and toxicity of mercury pose a serious threat to human health and the ecological environment. Therefore, the development of mercury-free catalysts has become a key breakthrough in promoting the green and sustainable development of the PVC industry.

[0003] Existing mercury-free catalysts mainly include precious metal catalysts and non-metallic catalyst systems. Among them, precious metal catalysts are expensive because their active components are mainly gold, and the reaction temperature requirements are high. If existing industries adopt them, they need to invest huge technical transformation costs, which hinders their large-scale promotion. Non-metallic catalysts have low activity and poor stability, and are currently mostly in the laboratory research stage. Summary of the Invention

[0004] In order to solve the problems existing in the prior art, the present disclosure provides a multi-component composite copper catalyst and a preparation method and application thereof.

[0005] According to a first aspect of the present disclosure, a multi-component composite copper catalyst is provided, wherein the composition of the multi-component composite copper catalyst is expressed as CuXYZ / AC; wherein AC is activated carbon as a carrier, Cu is a copper precursor supported on the activated carbon, X is an auxiliary agent, Y is a non-precious metal chloride, and Z is a chelating agent; wherein the copper precursor includes one or more of copper chloride, copper nitrate, copper phosphate, and copper sulfate; the auxiliary agent includes one or more of methyldiphenylphosphine oxide, triphenylphosphine oxide, 3-methyl-1-phenyl-2-phosphine-1-oxide, tetrabutylphosphine chloride, hexamethylphosphamide, 3-methyl-2-pyridone, pyridine, imidazole, pyrrolidone, 1,1-thiocarbonyldi-2-pyridone, sodium thiosulfate, thiourea, and sulfenamide; the non-precious metal chloride includes one or more of potassium chloride, sodium chloride, rubidium chloride, cesium chloride, zinc chloride, ferric chloride, and aluminum chloride; and the chelating agent includes one or more of polyvinylpyrrolidone and polyethylene glycol.

[0006] In one embodiment of the present disclosure, in the multi-component composite copper catalyst, the mass fraction of copper is 12% to 15%, the mass fraction of the auxiliary agent is 3% to 10%, the mass fraction of the non-precious metal chloride is 0.1% to 2%, and the mass fraction of the chelating agent is 0.1% to 1%.

[0007] According to a second aspect of the present disclosure, a method for preparing a multi-component composite copper catalyst is provided, comprising the following steps: Step S1: Select activated carbon, soak the activated carbon in an acid solution for 0.5 to 5 hours, rinse with deionized water, and dry for later use; Step S2: preparing a solution of a copper precursor, an additive X, a non-noble metal chloride Y and a chelating agent Z; Step S3: mixing the solution in step S2 with the activated carbon prepared in step S1, and performing microwave-assisted dispersion, drying the mixed activated carbon to obtain the multi-component composite copper catalyst, which is represented by CuXYZ / AC.

[0008] In one embodiment of the present disclosure, the acid solution in step S1 is one or more of hydrochloric acid, nitric acid, sulfuric acid, carbonic acid, phosphoric acid, and perchloric acid.

[0009] In one embodiment of the present disclosure, the molar concentration of the acid solution is 0.5 mol / L to 5 mol / L.

[0010] In one embodiment of the present disclosure, the soaking temperature in step S1 is 20°C to 80°C.

[0011] In one embodiment of the present disclosure, the solvent used to prepare the solution in step S2 includes one or more of water and ethanol.

[0012] In one embodiment of the present disclosure, the microwave power in step S3 is 300W to 500W, and the processing time is 0.1h to 2h.

[0013] In one embodiment of the present disclosure, the drying temperature in step S1 and step S3 is 40° C. to 120° C., and the drying time is 2 hours to 48 hours.

[0014] According to a third aspect of the present disclosure, there is provided an application of a multi-component composite copper catalyst, comprising the following steps: Step a: The multi-component composite copper catalyst is loaded into a fixed bed reactor and dried by nitrogen; Step b: introducing hydrogen chloride into the fixed bed reactor dried in step a for activation, and then introducing acetylene for reaction; Wherein, the multi-component composite copper catalyst is prepared by the preparation method of the multi-component composite copper catalyst as described above.

[0015] The present disclosure provides a multi-component composite copper catalyst, its preparation method, and application. A complex is formed between an additive and a copper precursor to stabilize the copper valence state. Furthermore, the non-precious metal chloride increases the electron cloud density around the copper precursor, thereby enhancing the hydrogen chloride adsorption effect. Furthermore, the introduction of a chelating agent enhances the interaction between the copper precursor and the activated carbon support, thereby inhibiting the loss of the copper precursor and ultimately improving the activity and operating life of the multi-component composite copper catalyst. Furthermore, the present disclosure achieves atomic-level dispersion through microwave-assisted impregnation during the preparation process, enhancing the stability of the catalyst.

[0016] Further features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0018] Figure 1 This is a flow chart of a method for preparing a multi-component composite copper catalyst provided in one embodiment of the present disclosure; Figure 2 This is a flow chart of the application of a multi-component composite copper catalyst provided in one embodiment of the present disclosure. DETAILED DESCRIPTION

[0019] In order to make the invention purpose, technical solution and beneficial technical effect of this application clearer, this application is described in detail below with reference to specific embodiments. It should be understood that the embodiments described in this specification are only for explaining this application and are not intended to limit this application.

[0020] For simplicity, only some numerical ranges are explicitly disclosed herein. However, any lower limit can be combined with any upper limit to form an unspecified range; and any lower limit can be combined with other lower limits to form an unspecified range, and likewise, any upper limit can be combined with any other upper limit to form an unspecified range. In addition, although not explicitly stated, each point or individual value between the endpoints of a range is included in the range. Thus, each point or individual value can serve as its own lower limit or upper limit and be combined with any other point or individual value, or with other lower limits or upper limits, to form an unspecified range.

[0021] In the description of this article, it should be noted that, unless otherwise specified, “above” and “below” include the number itself, and “several” in “one or several” means two or more.

[0022] The above summary of the invention of this application is not intended to describe every disclosed embodiment or every implementation in this application. The following description more specifically illustrates exemplary embodiments. In many places throughout the application, guidance is provided by a series of examples, which can be used in various combinations. In each example, the enumeration is intended only as a representative group and should not be construed as exhaustive.

[0023] First, the terms involved in one or more embodiments are explained.

[0024] Gas Hourly Space Velocity (GHSV) is an important parameter used in chemical engineering to describe the flow rate of gas in a fixed bed reactor. It is defined as the volume of gas passing through a unit volume of catalyst per unit time, usually expressed as standard cubic meters of gas passing through each cubic meter of catalyst per hour (m 3 / (m 3 h) or h -1 ). Simply put, the space velocity reflects the length of time the gas is in contact with the catalyst.

[0025] AC: It is the abbreviation of the English word "Activated Carbon", which means activated carbon.

[0026] Polyvinyl chloride (PVC), one of the main general-purpose resins, boasts high strength, corrosion resistance, and low cost, making it widely used in industry, agriculture, construction, and technology. The monomer for synthesizing PVC is vinyl chloride, and its production processes include the calcium carbide method (acetylene method), the ethylene method, the ethylene oxychlorination method, and the ethane oxychlorination method. However, due to China's energy structure characterized by high coal, low oil, and low gas consumption, the calcium carbide method has become the primary production process in China. The production of vinyl chloride by the calcium carbide method primarily involves the following two steps: Step 1: Calcium carbide reacts with water to produce acetylene CaC2+2H2O→C2H2↑+Ca(OH)2 In this process, calcium carbide (CaC2) reacts with water to produce acetylene gas (C2H2) and calcium hydroxide (Ca(OH)2).

[0027] Step 2: Acetylene reacts with hydrogen chloride to produce vinyl chloride C2H2+HCl→CH2=CHCl The generated acetylene gas reacts with hydrogen chloride (HCl) in the presence of a catalyst to form vinyl chloride monomer.

[0028] Finally, the vinyl chloride monomer undergoes polymerization reaction under the action of an initiator to form polyvinyl chloride (PVC).

[0029] The current catalyst used in the industrial calcium carbide process for producing vinyl chloride is activated carbon-supported mercuric chloride. However, mercury is volatile and deadly, posing a serious threat to humans and the environment. The development of mercury-free catalysts is essential for ensuring the green and sustainable development of the polyvinyl chloride industry. Mercury-free catalysts primarily include precious metal catalysts, non-precious metal catalysts, and non-metallic catalyst systems. Precious metal catalysts, due to their high activity and stability, have been the most widely studied and pioneered in industrial substitution efforts. However, their high cost and high reaction temperature requirements, as they are primarily gold-based active components, require significant technological upgrades for existing industries, hindering their widespread adoption. Non-metallic catalysts, on the other hand, suffer from low activity and poor stability, and are currently largely confined to laboratory research. Therefore, developing non-precious metal catalysts that combine high activity and stability with industrial production is a pressing need to overcome bottlenecks in the green development of the polyvinyl chloride industry.

[0030] In order to solve the problems existing in the prior art, the present disclosure provides a multi-component composite copper catalyst, expressed as CuXYZ / AC; wherein AC is activated carbon as a carrier, Cu is a copper precursor supported on the activated carbon, X is an auxiliary agent, Y is a non-precious metal chloride, and Z is a chelating agent; wherein the copper precursor includes one or more of copper chloride, copper nitrate, copper phosphate, and copper sulfate; the auxiliary agent includes one or more of methyldiphenylphosphine oxide, triphenylphosphine oxide, 3-methyl-1-phenyl-2-phosphine-1-oxide, tetrabutylphosphine chloride, hexamethylphosphoramide, 3-methyl-2-pyridone, pyridine, imidazole, pyrrolidone, 1,1-thiocarbonyldi-2-pyridone, sodium thiosulfate, thiourea, and sulfenamide; the non-precious metal chloride includes one or more of potassium chloride, sodium chloride, rubidium chloride, cesium chloride, zinc chloride, ferric chloride, and aluminum chloride; and the chelating agent includes one or more of polyvinylpyrrolidone and polyethylene glycol.

[0031] Specifically, the present invention uses a copper precursor as the active component of the catalyst and selects activated carbon as the carrier, which provides a large number of active sites for the catalytic reaction, which is beneficial to improving the catalytic efficiency. In addition, the activated carbon has a developed micropore, mesopore and macropore structure. This multi-level pore structure helps the uniform diffusion of the active component, thereby improving the loading rate of the active component.

[0032] Furthermore, in order to prevent the problem of catalyst deactivation due to loss of active components, the present invention discloses that, in addition to loading the active component copper precursor on the activated carbon carrier, multiple functional components such as auxiliary agents, non-precious metal chlorides and chelating agents are introduced. Among them, the auxiliary agents include one or more of methyl diphenylphosphine oxide, triphenylphosphine oxide, 3-methyl-1-phenyl-2-phosphine ene-1-oxide, tetrabutylphosphine chloride, hexamethylphosphamide, 3-methyl-2-pyridone, pyridine, imidazole, pyrrolidone, 1,1-thiocarbonyl di-2-pyridone, sodium thiosulfate, thiourea and sulfenamide. The lone pair electrons in the above auxiliary agents can react with copper ions to form coordination bonds, generating a stable complex structure, thereby effectively maintaining the valence stability of the copper ions.

[0033] Non-precious metal chlorides include one or more of potassium chloride, sodium chloride, rubidium chloride, cesium chloride, zinc chloride, ferric chloride, and aluminum chloride. Non-precious metal chlorides provide electrons to the copper precursor, increasing the electron cloud density around it, thereby enhancing the catalyst's adsorption capacity and reactivity for hydrogen chloride molecules. Chelating agents include one or more of polyvinyl pyrrolidone and polyethylene glycol. On the one hand, the chelating agent can combine with the oxygen-containing functional groups on the surface of the activated carbon through hydrogen bonds or van der Waals forces in its molecules to form a strong physical adsorption, thereby providing an "anchor" site for the copper precursor; on the other hand, the hydrophilic chain segments contained in the chelating agent molecules can also combine with the polar part of the copper precursor to construct a "bridge" structure, further firmly fixing the copper precursor on the carrier. With the synergistic effect between the above-mentioned copper precursor, additives, non-precious metal chlorides and chelating agents, the risk of loss of active components during use can be significantly reduced, thereby effectively improving the catalytic performance of the multi-component composite copper catalyst and its long-term operating stability.

[0034] In one embodiment of the present disclosure, in the multi-component composite copper catalyst, the mass fraction of copper is 12% to 15%, the mass fraction of the auxiliary agent is 3% to 10%, the mass fraction of the non-precious metal chloride is 0.1% to 2%, and the mass fraction of the chelating agent is 0.1% to 1%.

[0035] Specifically, the mass fraction of copper on the multi-component composite copper catalyst is 12% to 15%, indicating that the multi-component composite copper catalyst is loaded with a sufficient amount of active component Cu. 2+ The mass fraction of the additive is 3% to 10%, which can fully react with the copper precursor to form a complex, thereby stabilizing the copper valence and preventing Cu 2+ It is reduced to Cu and accumulates on the catalyst surface.

[0036] The mass fraction of the non-precious metal chloride is 0.1% to 2%, which is used to provide electrons to the copper precursor, thereby increasing the electron cloud density around the active component copper precursor and enhancing the catalyst's adsorption capacity for hydrogen chloride. The composition content of the non-precious metal chloride is relatively small, which can prevent the loss of the additive caused by the reaction of excess non-precious metal chloride with the additive.

[0037] The mass fraction of the chelating agent is 0.1% to 1%. It can combine with the oxygen-containing functional groups on the surface of the activated carbon through its own hydrogen bonds or van der Waals forces. This adsorption effect can provide an "anchor" site for the copper precursor and combine with the polar part of the copper precursor through the hydrophilic chain segments on it to form a "bridge" structure, stably fixing the copper precursor on the activated carbon carrier, thereby reducing the loss of active components and ultimately improving the activity and service life of the copper catalyst.

[0038] like Figure 1 As shown, this embodiment provides a method for preparing a multi-component composite copper catalyst, which specifically includes the following steps: Step S1: Select activated carbon, soak it in an acid solution for 0.5 to 5 hours, then rinse it with deionized water and dry it for later use; Step S2: preparing a solution of a copper precursor, an additive X, a non-noble metal chloride Y and a chelating agent Z; Step S3: mixing the solution in step S2 with the activated carbon prepared in step S1, and performing microwave-assisted dispersion, drying the mixed activated carbon to obtain a multi-component composite copper catalyst, which is represented by CuXYZ / AC.

[0039] Specifically, when preparing the multi-component composite copper catalyst, the present disclosure first needs to pre-treat the activated carbon carrier in step S1, that is, the activated carbon carrier is placed in an acid solution and soaked for 0.5h to 5h. This is to fully remove impurities that may be introduced into the activated carbon, such as calcium carbonate, calcium sulfate and other metal oxides, and the acid solution can also dissolve inorganic salt deposits in the pores of the activated carbon, thereby unblocking the micropores and mesopores in the activated carbon, thereby improving the adsorption performance of the activated carbon. The activated carbon carrier after acid washing also needs to be washed with deionized water to neutrality. This is to remove excess acid solution on the activated carbon and prevent it from reacting with subsequent active components. The activated carbon after water washing is placed in an oven for drying, which can remove the moisture remaining on the activated carbon carrier and prevent excess moisture from occupying the pore structure of the activated carbon and reducing its available effective surface area.

[0040] Furthermore, in step S2, a copper precursor, additive, non-precious metal chloride, and chelating agent are prepared into a solution. In step S3, this solution is mixed with a pretreated activated carbon support under the assistance of microwaves, so that the activated carbon support is evenly loaded with the active components of the copper precursor, additive, non-precious metal chloride, and chelating agent. The microwave-assisted impregnation directly accelerates the diffusion of the solution into the pores within the support, promoting its penetration into the fine structure of the support material, thereby improving the quality of the final catalyst product. Finally, the mixed activated carbon is placed in an oven to dry, producing a multi-component composite copper catalyst, denoted as CuXYZ / AC.

[0041] In one embodiment of the present disclosure, the acid solution in step S1 is one or more of hydrochloric acid, nitric acid, sulfuric acid, carbonic acid, phosphoric acid, and perchloric acid.

[0042] Specifically, during the production or use of activated carbon, impurities such as calcium carbonate, calcium sulfate, and other metal oxides may be introduced. Pre-treating the activated carbon with one or more acid solutions selected from hydrochloric acid, nitric acid, sulfuric acid, carbonic acid, phosphoric acid, or perchloric acid allows the acid solution to react chemically with these impurities, dissolving them and removing them from the activated carbon. The acid solution also removes inorganic salt deposits from the activated carbon's pores, unblocking the micropores and mesopores, and improving the surface physical and chemical properties, significantly enhancing its adsorption performance.

[0043] In one embodiment of the present disclosure, the molar concentration of the acid solution is 0.5 mol / L to 5 mol / L.

[0044] Specifically, during the pickling process, the molar concentration of the acid solution needs to be strictly controlled within a reasonable range. This is because in practical applications, the concentration directly affects the pickling effect, the degree of material corrosion, process costs, and safety. The present disclosure sets the molar concentration of the acid solution to 0.5 mol / L to 5 mol / L during pickling, which can effectively avoid the problems of high acid consumption and increased waste liquid treatment costs caused by excessively high concentrations. It also prevents the significant decrease in impurity dissolution rate and poor impurity removal effect caused by excessively low concentrations.

[0045] In one embodiment of the present disclosure, the soaking temperature in step S1 is 20°C to 80°C.

[0046] Specifically, while increasing the temperature appropriately helps speed up the reaction, too high a temperature will accelerate the volatilization of the acid, causing the concentration of the acid solution to decrease, affecting the cleaning effect. Therefore, setting the immersion temperature during pickling between 20°C and 80°C can increase the reaction rate while preventing waste caused by the volatilization of the acid solution.

[0047] In one embodiment of the present disclosure, the solvent used to prepare the solution in step S2 includes one or more of water and ethanol.

[0048] Specifically, ethanol, as a polar organic solvent, can effectively dissolve a variety of organic compounds, such as additives (one or more of methyldiphenylphosphine oxide, triphenylphosphine oxide, 3-methyl-1-phenyl-2-phosphine-1-oxide, tetrabutylphosphine chloride, hexamethylphosphamide, 3-methyl-2-pyridone, pyridine, imidazole, pyrrolidone, 1,1-thiocarbonyldi-2-pyridone, sodium thiosulfate, thiourea, and sulfenamide) and chelating agents (one or more of polyvinylpyrrolidone and polyethylene glycol), while water is good at dissolving ionic compounds, such as non-precious metal chlorides (one or more of potassium chloride, sodium chloride, rubidium chloride, cesium chloride, zinc chloride, ferric chloride, and aluminum chloride) and copper precursors (one or more of copper chloride, copper nitrate, copper phosphate, and copper sulfate). In addition, ethanol and water are miscible in any proportion, and after the two are miscible, the optimal dissolution effect of the target component can be achieved. In addition, ethanol is low in toxicity, volatile, and recyclable, while water is safe, harmless, and low-cost, making this combination excellent in safety and economy.

[0049] In one embodiment of the present disclosure, the microwave power in step S3 is 300W to 500W, and the processing time is 0.1h to 2h.

[0050] Specifically, the present invention uniformly mixes the solution prepared in S2 with the reserved activated carbon in S under the condition of a microwave power of 300W to 500W, and continuously microwaves for 0.1h to 2h. After completion, the mixture is placed in an oven for drying to obtain a multi-component composite copper catalyst. The use of microwave-assisted impregnation can directly accelerate the diffusion rate of the solution into the internal pores of the carrier and promote the solution to penetrate into the fine structure of the carrier material. This helps to overcome the problem of local concentration being too high or too low that may occur in traditional impregnation methods, thereby improving the quality of the final catalyst product.

[0051] Furthermore, when using microwave-assisted technology for catalyst impregnation, the selection of microwave power is crucial. Too high or too low a power can negatively impact the treatment effect. For example, too high a power may trigger chemical decomposition or deterioration reactions, reducing the quality and performance of the final product. Too low a power may not provide sufficient energy to ensure that the solution can quickly and evenly penetrate into the carrier, thereby affecting the effective loading amount of the active component and its distribution uniformity. Therefore, in order to achieve the ideal impregnation effect, the present disclosure has controlled the microwave power to between 300W and 500W after multiple tests, and given a treatment time of 0.1h to 2h to ensure the final loading effect.

[0052] In one embodiment of the present disclosure, the drying temperature in step S1 and step S3 is 40° C. to 120° C., and the drying time is 2 h to 48 h.

[0053] Specifically, the activated carbon after acid washing in step S1 needs to be placed in an oven at 40°C to 120°C and dried for 2h to 48h. This is because the acid washing process causes the activated carbon to absorb a large amount of moisture. If it is not thoroughly dried in subsequent steps, the residual moisture will occupy the pore structure of the activated carbon, reducing its available effective surface area, thereby affecting the loading rate of the activated carbon carrier.

[0054] Proper drying of the activated carbon after impregnation in step S3 helps stabilize the microporous structure inside the activated carbon, prevents pore expansion or collapse due to the presence of water or other solvents, and ensures that the physical form of the activated carbon is not damaged. Drying can also help the active components on the activated carbon to be better fixed on the surface or in the pores, reducing the loss of active components.

[0055] like Figure 2 As shown, the present disclosure also provides an application of a multi-component composite copper catalyst, comprising the following steps: Step a: The multi-component composite copper catalyst is loaded into a fixed bed reactor and dried by nitrogen; Step b: introducing hydrogen chloride into the fixed bed reactor dried in step a for activation, and then introducing acetylene for reaction; Wherein, the multi-component composite copper catalyst is prepared by the above preparation method.

[0056] Specifically, the multi-component composite copper catalyst prepared by the above preparation method is used in the reaction process of producing vinyl chloride by the calcium carbide process. In actual operation, in step a, the multi-component composite copper catalyst is first loaded into a fixed bed reactor and nitrogen is introduced for drying. This is because the presence of moisture may cause some unnecessary side reactions, which will not only reduce the yield of the target product, but also affect the product quality.

[0057] Secondly, in step b, hydrogen chloride is first introduced for activation, and then acetylene is introduced for reaction. When hydrogen chloride is introduced first, it can be pre-adsorbed on the catalyst surface and occupy some active sites. This pre-adsorption helps to regulate the subsequent behavior of acetylene molecules on the catalyst surface, making it easier for acetylene to be converted into the target product - vinyl chloride - according to the expected path, rather than undergoing polymerization or other side reactions.

[0058] Furthermore, during the reaction, the molar ratio of hydrogen chloride to acetylene is 1:1 to 1.5:1, the reaction temperature is 90°C to 200°C, and the acetylene space velocity is 5h -1 Up to 300 hours -1. Theoretically, the synthesis of vinyl chloride requires equal moles of HCl and C2H2. However, the present disclosure controls the molar ratio of hydrogen chloride to acetylene to 1:1 to 1.5:1, with the aim of making hydrogen chloride slightly excessive to ensure that all acetylene participates in the reaction, thereby maximizing the yield of vinyl chloride and reducing problems caused by unreacted acetylene entering the downstream system. Since temperature has a significant effect on the rate of chemical reactions, higher temperatures generally accelerate the reaction, but excessively high temperatures may cause acetylene decomposition or trigger other non-target reactions. Therefore, after multiple experiments, the present disclosure controls the reaction temperature between 90°C and 200°C, which can ensure a sufficiently fast reaction rate while maintaining high selectivity of the reaction. 5h -1 Up to 300 hours -1 The acetylene space velocity between 0.1 and 1.5 is suitable for various scenarios from small-scale experimental research to large-scale industrial production.

[0059] Furthermore, based on the above application process and referring to the following experimental examples and comparative examples, it is illustrated that the multi-component composite copper catalyst prepared by the preparation method disclosed herein has a high acetylene conversion rate in the reaction process of producing vinyl chloride by the calcium carbide process.

[0060] Experimental Example 1 Select activated carbon with a large pore size and place it in a sufficient amount of 1 mol / L hydrochloric acid solution. After stirring and soaking at room temperature for 2 hours, wash it with deionized water until neutral, then dry it in a 100°C oven for 12 hours before use. Weigh 12g of copper chloride, 5g of methyldiphenylphosphine oxide, 0.2g of potassium chloride, and 0.1g of polyvinylpyrrolidone to prepare a solution. Add the solution dropwise to 25g of the treated activated carbon at a microwave power of 400W. Continue microwave treatment for 1 hour, then dry it in a 100°C oven for 12 hours to obtain Catalyst A.

[0061] Experimental Example 2 Select activated carbon with a large pore size and place it in a sufficient amount of 1 mol / L hydrochloric acid solution. After stirring and soaking at room temperature for 2 hours, wash it with deionized water until neutral, then dry it in a 100°C oven for 12 hours and set aside. Weigh 12g of copper chloride, 5g of 3-methyl-1-phenyl-2-phosphine-1-oxide, 0.2g of potassium chloride, and 0.1g of polyvinylpyrrolidone to prepare a solution. Add the solution dropwise to 25g of the treated activated carbon at a microwave power of 400W. Continue microwave treatment for 1 hour, and then dry it in a 100°C oven for 12 hours to obtain Catalyst B.

[0062] Experimental Example 3 Select activated carbon with a large pore size and place it in a sufficient amount of 1 mol / L hydrochloric acid solution. After stirring and soaking at room temperature for 2 hours, wash it with deionized water until neutral, then dry it in a 100°C oven for 12 hours and set aside. Weigh 12g of copper chloride, 5g of 3-methyl-2-pyridone, 0.3g of zinc chloride, and 0.1g of polyethylene glycol to form a solution. Add the solution dropwise to 25g of the treated activated carbon at a microwave power of 400W. Continue microwave treatment for 1 hour, and then dry it in a 100°C oven for 12 hours to obtain Catalyst C.

[0063] Experimental Example 4 Select activated carbon with a large pore size and place it in a sufficient amount of 1 mol / L hydrochloric acid solution. After stirring and soaking at room temperature for 2 hours, wash it with deionized water until neutral, then dry it in a 100°C oven for 12 hours and set aside. Weigh 12g of copper chloride, 10g of 1,1-thiocarbonyldi-2-pyridone, 0.3g of ferric chloride, and 0.1g of polyethylene glycol to form a solution. Add the solution dropwise to 25g of the treated activated carbon at a microwave power of 400W. Continue microwave treatment for 2 hours, then dry it in a 100°C oven for 12 hours to obtain Catalyst D.

[0064] Comparative Example 1 Select activated carbon with a large pore size and place it in a sufficient amount of 1 mol / L hydrochloric acid solution. After stirring and soaking at room temperature for 2 hours, wash it with deionized water until neutral, then dry it in a 100°C oven for 12 hours before use. Weigh 12g of copper chloride to prepare a solution, then add the solution dropwise with stirring to 25g of the treated activated carbon. After completion, dry it in a 100°C oven for 12 hours to obtain Catalyst E.

[0065] Comparative Example 2 Select activated carbon with a large pore size and place it in a sufficient amount of 1 mol / L hydrochloric acid solution. After stirring and soaking at room temperature for 2 hours, wash it with deionized water until neutral, then dry it in a 100°C oven for 12 hours and set aside. Weigh 12g of copper chloride and 5g of methyldiphenylphosphine oxide to form a solution. Then, add the solution dropwise with stirring to 25g of the treated activated carbon. After completion, dry it in a 100°C oven for 12 hours to obtain Catalyst F.

[0066] Comparative Example 3 Select activated carbon with a large pore size and place it in a sufficient amount of 1 mol / L hydrochloric acid solution. After stirring and soaking at room temperature for 2 hours, wash it with deionized water until neutral, then dry it in a 100°C oven for 12 hours before use. Weigh 12g of copper chloride, 5g of methyldiphenylphosphine oxide, and 0.2g of potassium chloride to form a solution. Then, add the solution dropwise with stirring to 25g of the treated activated carbon. After completion, dry it in a 100°C oven for 12 hours to obtain Catalyst G.

[0067] Comparative Example 4 Select activated carbon with a large pore size and place it in a sufficient amount of 1 mol / L hydrochloric acid solution. After stirring and soaking at room temperature for 2 hours, wash it with deionized water until neutral, then dry it in a 100°C oven for 12 hours before use. Weigh 12g of copper chloride, 5g of methyldiphenylphosphine oxide, 0.2g of potassium chloride, and 0.1g of polyvinylpyrrolidone to form a solution. Then, add the solution dropwise with stirring to 25g of the treated activated carbon. After completion, dry it in a 100°C oven for 12 hours to obtain Catalyst H.

[0068] Comparative Example 5 Select activated carbon with a large pore size and place it in a sufficient amount of 1 mol / L hydrochloric acid solution. After stirring and soaking at room temperature for 2 hours, the mixture was washed with deionized water until neutral and then dried in a 100°C oven for 12 hours before use. Weigh 12g of copper chloride to prepare a solution, then add the solution dropwise to 25g of the treated activated carbon at a microwave power of 400W. The microwave treatment was continued for 2 hours, and then dried in a 100°C oven for 12 hours to obtain Catalyst I.

[0069] 10 mL of each catalyst prepared in the above examples and comparative examples was taken and loaded into a fixed bed reactor. Nitrogen was introduced and heated to 110°C and dried for 1 hour. Then, hydrogen chloride was introduced for activation for 1 hour. Then, a mixture of hydrogen chloride and acetylene was introduced at a temperature of 110°C and a space velocity of 120 h. -1 The reaction was carried out under the conditions of HCl / C2H2, wherein the volume ratio of HCl / C2H2 was 1.08. The experimental results of the above embodiments and comparative examples are shown in Table 1.

[0070] Table 1

[0071] From the above content, it can be seen that in Comparative Example 1, only the active component copper precursor is introduced, in Comparative Example 2, the active component copper precursor and the auxiliary agent are introduced, in Comparative Example 3, the active component copper precursor, the auxiliary agent and the non-precious metal chloride are introduced, and in Comparative Example 4, the active component copper precursor, the auxiliary agent, the non-precious metal chloride and the chelating agent are introduced. According to the experimental data of Comparative Examples 1-4 in Table 1, it can be seen that the simultaneous introduction of auxiliary agents, non-precious metal chlorides and chelating agents can effectively improve the conversion rate of acetylene.

[0072] In addition, compared with Experimental Examples 1-4, Comparative Example 4 adds a microwave-assisted treatment step in Experimental Examples 1-4, and the acetylene conversion rate of Experimental Examples 1-4 is higher than that of Comparative Example 4; and compared with Comparative Example 1, Comparative Example 5 also adds a microwave-assisted treatment step in Comparative Example 5, and the acetylene conversion rate of Comparative Example 5 is higher than that of Comparative Example 1. Therefore, adding the microwave treatment step can effectively increase the loading rate of the active component on the activated carbon, thereby increasing the conversion rate of acetylene.

[0073] Furthermore, in the preparation of multi-component composite copper catalysts A, B, C, and D in Experimental Examples 1-4 of the present disclosure, copper precursors, additives, non-precious metal chlorides, and chelating agents were introduced simultaneously, and microwave-assisted impregnation was used. According to the data in Table 1, the catalysts were -1 Under the conditions of acetylene space velocity, the acetylene conversion rates of catalysts A, B, C, and D are all greater than 85%, which is greater than the acetylene conversion rates of comparative examples 1-5, and the vinyl chloride selectivities are all greater than 99%, which is also greater than the vinyl chloride selectivities of comparative examples 1-5.

[0074] The present disclosure provides a multi-component composite copper catalyst, its preparation method, and application. The catalyst forms a complex with a copper precursor through an auxiliary agent, thereby stabilizing the copper valence state. In addition, the non-precious metal chloride can increase the electron cloud density around the copper precursor, thereby enhancing the hydrogen chloride adsorption effect. In addition, by introducing a chelating agent, the interaction between the copper precursor and the activated carbon carrier is enhanced, thereby inhibiting the loss of the copper precursor and ultimately improving the activity and service life of the multi-component composite copper catalyst. The present disclosure also achieves an atomic-level dispersion effect through microwave-assisted impregnation during the preparation process, thereby further enhancing the stability of the catalyst.

[0075] While various embodiments of the present invention have been described above, the foregoing description is intended to be illustrative, non-exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is selected to best explain the principles of the embodiments, their practical applications, or technological improvements in the marketplace, or to enable others skilled in the art to understand the embodiments disclosed herein. The scope of the present invention is defined by the appended claims.

Claims

1. A multi-component composite copper catalyst, characterized in that: The composition of the multi-component composite copper catalyst is expressed as CuXYZ / AC; wherein AC is activated carbon as a carrier, Cu is a copper precursor supported on the activated carbon, X is an auxiliary agent, Y is a non-precious metal chloride, and Z is a chelating agent; wherein the copper precursor includes one or more of copper chloride, copper nitrate, copper phosphate, and copper sulfate; the auxiliary agent includes one or more of methyldiphenylphosphine oxide, triphenylphosphine oxide, 3-methyl-1-phenyl-2-phosphine-1-oxide, tetrabutylphosphine chloride, hexamethylphosphamide, 3-methyl-2-pyridone, pyridine, imidazole, pyrrolidone, 1,1-thiocarbonyldi-2-pyridone, sodium thiosulfate, thiourea, and sulfenamide; the non-precious metal chloride includes one or more of potassium chloride, sodium chloride, rubidium chloride, cesium chloride, zinc chloride, ferric chloride, and aluminum chloride; and the chelating agent includes one or more of polyvinylpyrrolidone and polyethylene glycol.

2. The multi-component composite copper catalyst according to claim 1, characterized in that In the multi-component composite copper catalyst, the mass fraction of copper is 12% to 15%, the mass fraction of the auxiliary agent is 3% to 10%, the mass fraction of the non-precious metal chloride is 0.1% to 2%, and the mass fraction of the chelating agent is 0.1% to 1%.

3. A method for preparing a multi-component composite copper catalyst, characterized in that: The following steps are involved: Step S1: Select activated carbon, soak the activated carbon in an acid solution for 0.5 to 5 hours, rinse with deionized water, and dry for later use; Step S2: preparing a solution of a copper precursor, an additive X, a non-noble metal chloride Y and a chelating agent Z; Step S3: mixing the solution in step S2 with the activated carbon prepared in step S1, and performing microwave-assisted dispersion, drying the mixed activated carbon to obtain the multi-component composite copper catalyst, which is represented by CuXYZ / AC.

4. The preparation method according to claim 3, characterized in that The acid solution in step S1 is one or more of hydrochloric acid, nitric acid, sulfuric acid, carbonic acid, phosphoric acid, and perchloric acid.

5. The preparation method according to claim 4, characterized in that The molar concentration of the acid solution is 0.5 mol / L to 5 mol / L.

6. The preparation method according to claim 4, characterized in that The soaking temperature in step S1 is 20°C to 80°C.

7. The preparation method according to claim 3, characterized in that The solvent used to prepare the solution in step S2 includes one or more of water and ethanol.

8. The preparation method according to claim 3, characterized in that The microwave power in step S3 is 300W to 500W, and the processing time is 0.1h to 2h.

9. The preparation method according to claim 3, characterized in that The drying temperature in step S1 and step S3 is 40° C. to 120° C., and the drying time is 2 h to 48 h.

10. An application of a multi-component composite copper catalyst, characterized in that: The following steps are involved: Step a: The multi-component composite copper catalyst is loaded into a fixed bed reactor and dried by nitrogen; Step b: introducing hydrogen chloride into the fixed bed reactor dried in step a for activation, and then introducing acetylene for reaction; Wherein, the multi-component composite copper catalyst is prepared by the preparation method according to any one of claims 3-9.

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