A gold-based catalyst for the hydrochlorination of acetylene and a method for its preparation and regeneration

Abstract

This invention relates to a gold-based catalyst for the hydrochlorination of acetylene and its regeneration method, belonging to the field of chemical engineering. The catalyst is prepared by impregnation using microporous activated carbon as a support, loading gold active component HAuCl4, copper additive CuCl2·2H2O, and trichloroisocyanuric acid (TCCA) organic ligand. The regeneration method includes solvent cleaning to remove surface impurities, high-temperature calcination at 600°C under an inert atmosphere to remove carbon deposits, and TCCA solution impregnation to achieve re-oxidation of gold species. This method utilizes the dual-effect function of TCCA to precisely control the electronic structure of gold, avoiding excessive gold reduction and carbon deposition deactivation. After regeneration, the acetylene conversion rate of the catalyst recovers to over 65%, effectively solving the deactivation problem of gold-based catalysts and reducing industrial application costs.

Description

Technical Field

[0001] This invention relates to the application field of a gold-based catalyst for acetylene hydrochlorination, specifically a gold-based catalyst for acetylene hydrochlorination and its preparation and regeneration methods. Background Technology

[0002] Polyvinyl chloride (PVC) is widely used in light industry, construction, agriculture, power, and daily life due to its low cost and stable properties. Achieving mercury-free catalytic hydrochlorination of acetylene in the production of PVC monomer vinyl chloride is a significant strategic need.

[0003] In current mainstream research on mercury-free catalysis, gold-based catalysts exhibit higher activity and stability compared to ruthenium, palladium, and copper, and are considered the most likely mercury-free alternative for industrial application. Precisely controlling the electronic structure of the active domain of gold is a crucial design strategy in the preparation of gold-based catalysts. Numerous studies have shown that adding metal promoters is the most direct method to improve catalyst performance. Metal promoters such as copper, nickel, potassium, cobalt, silver, bismuth, and lanthanum can enhance the catalyst's adsorption capacity for acetylene, forming Au-M clusters to increase the electron density of gold and significantly improve catalyst activity. However, excessively strong acetylene adsorption inevitably accelerates carbon deposition and metal reduction on the catalyst surface, speeding up catalyst deactivation. Correspondingly, organic ligands can rationally regulate electron transfer between metals, optimize the catalytic reaction structure and reactant adsorption capacity, and improve both catalytic activity and catalyst stability, demonstrating a synergistic effect in the catalytic system.

[0004] However, even optimized gold-based catalysts can deactivate during catalysis. Oxidized gold species are reduced to Au(0), metal particles aggregate, and carbon deposits produced by side reactions mask the active sites of the catalyst, leading to deactivation. The high price of gold also severely limits its widespread application. Therefore, addressing the deactivation mechanism of gold-based catalysts and regenerating them to restore some catalytic activity and extend their lifespan is crucial for the efficient utilization of gold and a significant reduction in catalyst usage costs.

[0005] CN102631947B mentions a gold-based catalyst prepared based on potassium tetrathiocyanate and potassium chloride. Potassium chloride acts as a metal promoter, and potassium tetrathiocyanate acts as an organic ligand to regulate the electronic structure of gold. While maintaining a low gold complex content, this novel mercury-free catalyst exhibits high activity, high stability, and high selectivity, significantly reducing the cost of precious metal catalysts. CN105148989B mentions a supported ionic liquid-gold-based catalyst prepared using 1-butyl-3-methylimidazolium chloride and 1-ethyl-3-methylimidazolium tetrafluoroborate in combination with gold chloride and nickel chloride. This catalyst demonstrates good chemical and thermal stability and high thermal conductivity in the reaction atmosphere of acetylene hydrochlorination to vinyl chloride synthesis, exhibiting high catalytic activity and selectivity, good stability, and low cost.

[0006] CN114029052B mentions a regeneration method for noble metal catalysts based on impregnation with a mixed solution of nitric acid and perchloric acid. Strong oxidants can restore the noble metal to a high valence state, resulting in high activity in the initial stage after regeneration. However, problems exist, including potential rapid deactivation in the later stages of the reaction, as the active sites of the metal are not stably regulated; strong oxidants, while oxidizing and dissolving carbon deposits, also damage the carbon structure of the support; and the strong oxidants may dissolve the noble metal, leading to its loss from the catalyst. CN110586200A mentions a regeneration method based on nitrogen roasting and potassium permanganate oxidant treatment. Proper temperature control during nitrogen roasting can effectively remove carbon deposits, and strong oxidants can effectively oxidize gold species. However, problems exist, including the difficulty in maintaining the oxidized state of gold during the reaction, with rapid deactivation still occurring; and wear during deactivation, posing a challenge in removing catalyst powder and particulate dust formed by byproducts.

[0007] In summary, the existing technology still has the following defects and shortcomings: 1. Precise control of the local structure of gold during preparation is difficult: During the reaction, it is necessary to provide gold with electrons through ligands and metal auxiliaries to increase its electron density and enhance its adsorption capacity for acetylene, while controlling the metal to prevent it from being reduced to its elemental form and losing its activity. At the same time, it is necessary to form efficient catalytic sites to reduce the formation of carbon deposits and the agglomeration of metal particles.

[0008] 2. Difficulty in removing carbon deposits as byproducts during regeneration: During the reaction, acetylene reacts excessively with gold species to generate carbon deposits, which cover the gold active sites, leading to catalyst deactivation. Since the main component of carbon deposits is carbon, and the catalyst support is microporous activated carbon, how to efficiently remove carbon deposits without damaging the original microporous structure of the catalyst support is a crucial step in achieving regeneration.

[0009] 3. Complex re-oxidation of gold species during regeneration: During the reaction, excessively high local concentrations of acetylene can reduce gold species to Au(0), leading to catalyst deactivation. In the catalyst regeneration process, the key to achieving stable catalysis is to determine which oxidant can be used to enable rapid reduction of gold and maintain efficient catalytic sites in subsequent reactions. Summary of the Invention

[0010] This invention provides an acetylene hydrochlorination gold-based catalyst and its preparation and regeneration method. Based on the addition of the metal promoter copper chloride, the same additive, trichloroisocyanuric acid, is used in both the catalyst preparation and regeneration processes. The specific scheme is as follows: A gold-based catalyst for the acetylene hydrochlorination reaction is prepared by impregnation with microporous activated carbon as a carrier, adding a gold active component, a copper auxiliary and an organic ligand. The gold active component is HAuCl4, the copper auxiliary is CuCl2·2H2O, and the organic ligand is trichloroisocyanuric acid (TCCA).

[0011] The second aspect of this application provides a method for preparing a gold-based catalyst for the acetylene hydrochlorination reaction. The steps are as follows: activated carbon pretreatment → preparation of a mixed impregnation solution containing gold active components, copper additives and organic ligands → equal volume impregnation → drying → finished catalyst. In the preparation method, the copper additive is added according to a Cu to Au molar ratio of (5~30):1, and the organic ligand is added according to a trichloroisocyanuric acid (TCCA) to Au molar ratio of (5~20):1.

[0012] The third aspect of this application provides a method for regenerating a gold-based catalyst for the acetylene hydrochlorination reaction, the regeneration method comprising the following steps: (1) solvent cleaning: the deactivated catalyst is solvent cleaned to remove some surface impurities; (2) Calcination activation: The cleaned catalyst is calcined at high temperature under an inert atmosphere to efficiently remove carbon deposits; (3) Catalyst regeneration: The calcined and activated catalyst is immersed in a hydrochloric acid solution containing trichloroisocyanuric acid (TCCA), and the solvent is slowly evaporated and dried by water bath heating to obtain the regenerated catalyst.

[0013] In one optional embodiment, the solvent cleaning process in step (1) consists of stirring, sonication, filtration and drying in sequence.

[0014] In one alternative embodiment, the solvent includes one or more of ethanol, isopropanol, dichloromethane, acetonitrile, ethyl acetate, and N,N-dimethylformamide.

[0015] In an optional embodiment, the inert gas flow rate in step (2) is 200 mL / min and the calcination temperature is 300~600℃.

[0016] In one optional embodiment, the calcination process involves first raising the temperature to 120°C at a rate of 10°C / min, maintaining it for 30 minutes to remove moisture, then replacing the overall atmosphere inside the furnace, followed by raising the temperature to 600°C at a rate of 5°C / min, and then calcining for 2 hours before naturally cooling down.

[0017] In an optional embodiment, the ratio of trichloroisocyanuric acid to gold in the ligand re-addition process in step (3) is (5~25):1.

[0018] In an optional embodiment, the concentration of hydrochloric acid used in step (3) is 0.1-6 mol / L.

[0019] In an optional embodiment, during the ligand re-addition process, the calcined catalyst is immersed in a solution containing trichloroisocyanuric acid (TCCA), the mixture is then sealed with a plastic film and placed in a water bath at 70°C. After 12 hours, holes are punched in the surface of the plastic film to allow the solvent to evaporate slowly. After the solvent has completely evaporated, the sample is transferred to an oven at 120°C for drying.

[0020] The gold-based catalyst for the acetylene hydrochlorination reaction and its preparation and regeneration method disclosed in this application have the following advantages: This scheme achieves precise control over the oxidation state and dispersion of gold species through the dual-functional design of trichloroisocyanuric acid (TCCA) as both an organic ligand and an oxidant.

[0021] Highly dispersed gold species are formed by providing gold active components through HAuCl4, and CuCl2·2H2O is used as a copper auxiliary to form a synergistic electron transfer structure with gold, which enhances the adsorption capacity for acetylene molecules. At the same time, the oxidation properties of TCCA are used to inhibit the reduction of gold from the high valence state to the elemental state, thus avoiding the loss of active sites.

[0022] Furthermore, in the regeneration method, surface impurities are removed by solvent cleaning, and carbon deposits are efficiently removed by high-temperature calcination in an inert atmosphere while protecting the microporous structure of the support. Finally, the reduced gold is re-oxidized to an active high-valence state through a TCCA re-addition process, rebuilding a stable gold-ligand structure. This design not only solves the problem of decreased catalytic efficiency caused by carbon deposits covering active sites, but also avoids the damage to the support structure and the risk of precious metal loss caused by traditional strong oxidant regeneration methods. This allows the acetylene conversion rate of the regenerated catalyst to be restored to over 65%, significantly extending the catalyst's lifespan. Attached Figure Description

[0023] Figure 1 These are characterization graphs of the catalytic performance of the different catalysts prepared in Example 1; Figure 2This is a characterization diagram of the pilot-scale catalytic performance of the catalyst AuCuTCCA / AC in Example 1; Figure 3 This is a comparison of the catalytic performance of the regenerated catalyst AuCuTCCA / AC and the deactivated catalyst in Comparative Example 1. Figure 4 This is a comparison of the catalytic performance of the regenerated catalyst AuCuTCCA / AC and the deactivated catalyst in Comparative Example 2. Figure 5 This is a comparison of the catalytic performance of the regenerated catalyst AuCuTCCA / AC and the deactivated catalyst in Comparative Example 3. Figure 6 This is a comparison of the catalytic performance of the regenerated catalyst AuCuTCCA / AC and the deactivated catalyst in Comparative Example 4. Figure 7 This is a comparison of the catalytic performance of the regenerated catalyst AuCuTCCA / AC and the deactivated catalyst in Comparative Example 5. Detailed Implementation

[0024] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0025] Preferred Implementation 1. Composition of the gold-based catalyst for the acetylene hydrochlorination reaction: It is prepared by impregnation method. The catalyst support is microporous activated carbon, the main active component is HAuCl4, the gold loading is 0.15 wt.% (based on the support mass), the metal auxiliary is CuCl2·2H2O, the molar ratio of copper to gold is 5:1, the organic ligand is trichloroisocyanuric acid (TCCA), and the molar ratio of ligand to gold is 10:1.

[0026] 2. The preparation method of the above catalyst is as follows: (1) Pretreatment of activated carbon: 500.0 g of coal-based activated carbon was immersed in 1936 mL of dilute sulfuric acid solution (0.76 mol / L), and allowed to stand for 12 h at room temperature. Then it was heated in a 70℃ water bath for 4 hours, filtered with deionized water and washed until neutral, and finally dried in an oven at 150℃ to obtain the carrier material AC.

[0027] (2) Prepare a mixed impregnation solution containing gold active components, copper additives and organic ligands: Use 0.1 mol / L dilute hydrochloric acid as solvent, and add 0.0130 g of CuCl2·2H2O, 0.0052 g of HAuCl4 and 0.0354 g of trichloroisocyanuric acid (TCCA).

[0028] (3) Equal volume impregnation: Place the mixture in a 70°C oven and heat for half an hour to ensure that the ligands are completely dissolved, and then slowly add 2,000 g of AC to the solution.

[0029] (4) Drying: The impregnated mixture was then sealed with a plastic film and placed in a water bath at 70°C. After 12 hours, holes were punched in the surface of the plastic film to allow the solvent to evaporate slowly. After the solvent had completely evaporated, the sample was transferred to an oven at 120°C overnight to obtain the prepared AuCuTCCA / AC catalyst.

[0030] Similarly, AuCu / AC, AuTCCA / AC, Cu / AC, CuTCCA / AC, and TCCA / AC were also prepared using the above method.

[0031] 3. The process of using the above catalyst is as follows: (1) Test 1: Different types of catalysts prepared by the above preparation method were used in the acetylene hydrochlorination reaction for testing, with an acetylene volume hourly space velocity of 180 h⁻¹. −1 Under the conditions of a reaction temperature of 180℃ and a hydrogen chloride to acetylene feed ratio of 1.2, the reaction was initiated by activating with hydrogen chloride under nitrogen atmosphere for 60 min, followed by the introduction of acetylene. The performance was as follows: Figure 1 As shown, Figure 1 As can be seen from the data, the maximum acetylene conversion of AuCuTCCA / AC is 94%, and the selectivity is 99%.

[0032] (2) Test 2: The catalyst AuCuTCCA / AC was used in a pilot test of the acetylene hydrochlorination reaction. 5 kg of columnar catalyst was loaded in an industrial single-tube fixed-bed reactor, and the acetylene volume hourly space velocity was 18 h⁻¹. −1 The catalyst lifetime was tested under the conditions of a reaction temperature of 150℃ and a hydrogen chloride to acetylene feed ratio of 1.03. The results are as follows: Figure 2 As shown, the catalyst has a maximum conversion rate of 99% and a test life of 3300 hours. The deactivated catalyst obtained after the reaction was used for regeneration research.

[0033] 4. Regeneration method of AuCuTCCA / AC catalyst (1) Solvent cleaning: The deactivated catalyst is cleaned with solvent. The process includes stirring, sonication, filtration and drying. The solvents used include one or more of ethanol, isopropanol, dichloromethane, acetonitrile, ethyl acetate and N,N-dimethylformamide. In this example, 20 mL isopropanol + 20 mL acetonitrile is preferred. (2) Calcination activation: First, the temperature is raised to 120°C at a rate of 10°C / min and maintained for 30 minutes to remove moisture. Then, the atmosphere inside the furnace is replaced with argon gas, and the argon gas flow rate is controlled at 200 mL / min. After that, the temperature is raised to 600°C at a rate of 5°C / min. Calcination is carried out in an argon atmosphere and kept at that temperature for 2 hours. Then, the temperature is cooled down naturally.

[0034] (3) Catalyst regeneration: Trichloroisocyanuric acid was dissolved in 1 mol / L hydrochloric acid solution at a ratio of 10:1. The calcined catalyst was then immersed in the solution. The mixture was then sealed with a plastic film and placed in a water bath at 70°C. After 12 hours, holes were punched in the surface of the plastic film to allow the solvent to evaporate slowly. After the solvent had completely evaporated, the sample was transferred to an oven at 120°C and dried overnight to obtain the regenerated catalyst.

[0035] Comparative Example 1: Method for regenerating the catalyst obtained in Example 1 Step 1: Take 5,000 g of deactivated catalyst and add it to a mixed solution of 20 mL isopropanol and 20 mL acetonitrile. Stir magnetically at 100-200 rpm for 15 min. After repeated washing and filtration, add solvent again, ultrasonically clean for 30 min, wash and filter repeatedly, and dry in an oven at 120℃ overnight.

[0036] Step 2: The cleaned catalyst was calcined in an argon atmosphere. First, the temperature was increased to 120°C at a rate of 10°C / min and maintained for 30 min to remove moisture and replace the overall atmosphere in the furnace. Then, the temperature was increased to 600°C at a rate of 5°C / min and calcined for 2 hours before being allowed to cool naturally. No obvious combustion phenomenon occurred on the carrier.

[0037] Step 3: Dissolve 0.0354 g of trichloroisocyanuric acid in 1 mol / L hydrochloric acid solution, then immerse 2.000 g of deactivated catalyst in the solution. Seal the mixture with a plastic film and place it in a 70°C water bath for 12 hours. Afterward, poke holes in the plastic film to allow slow evaporation of the dissolved solvent. Once the solvent has completely evaporated, transfer the sample to a 120°C oven overnight to obtain regenerated catalyst-1. The catalyst was then used in the acetylene hydrochlorination reaction at an acetylene volume hourly space velocity (HHSV) of 180 h⁻¹. −1 Under the conditions of a reaction temperature of 180℃ and a hydrogen chloride to acetylene feed ratio of 1.2, the reaction was initiated by introducing acetylene after activation with hydrogen chloride for 60 min in a nitrogen atmosphere. The highest acetylene conversion rate of regenerated catalyst-1 was 72%, and after 24 hours of reaction, the acetylene conversion rate was 67%, a decrease of only 5%. The selectivity for vinyl chloride was greater than 99%, and the performance was as described above. Figure 3 As shown.

[0038] Comparative Example 2: Method for regenerating the catalyst obtained in Example 1 Step 1: Take 5,000 g of deactivated catalyst and add it to 40 mL of ethyl acetate. Stir magnetically at 100-200 rpm for 15 min. After washing and filtering, add the solvent again and ultrasonically clean for 30 min. After repeated washing and filtering, dry in an oven at 120℃ overnight.

[0039] Step 2: Calcine the cleaned catalyst in a static air atmosphere. Initially, control the air flow rate to 200 mL / min and raise the temperature to 120℃ at a rate of 10℃ / min. Maintain this temperature for 30 min to remove moisture and replace the overall atmosphere in the furnace. Then, stop the air supply and maintain a static air atmosphere. Raise the temperature to 300℃ at a rate of 5℃ / min. After calcining for 2 hours, allow the catalyst to cool naturally. Small-scale combustion may occur on the carrier, causing the surface to turn white or burn to ash.

[0040] Step 3: Dissolve 0.0177 g of trichloroisocyanuric acid in 1 mol / L hydrochloric acid solution, then immerse 2.000 g of deactivated catalyst in the solution. Seal the mixture with a plastic film and place it in a 70°C water bath for 12 hours. Afterward, poke holes in the plastic film to allow slow evaporation of the dissolved solvent. Once the solvent has completely evaporated, transfer the sample to a 120°C oven overnight to obtain regenerated catalyst-2. The catalyst was then used in the acetylene hydrochlorination reaction at an acetylene volume hourly space velocity (HHSV) of 180 h⁻¹. −1 Under the conditions of a reaction temperature of 180℃ and a hydrogen chloride to acetylene feed ratio of 1.2, the reaction was initiated by introducing acetylene after activation with hydrogen chloride for 60 min in a nitrogen atmosphere. The highest acetylene conversion rate of the regenerated catalyst-2 was 74%, and after 24 hours of reaction, the acetylene conversion rate was 65%, a decrease of 9%, indicating poor stability. The selectivity for vinyl chloride was greater than 99%, and the performance was as follows. Figure 4 As shown.

[0041] Comparative Example 3: Method for regenerating the catalyst obtained in Example 1 Step 1: Take 5,000 g of deactivated catalyst and add it to 40 mL of acetonitrile. Stir magnetically at 100-200 rpm for 15 min. After washing and filtering, add the solvent again and ultrasonically clean for 30 min. After repeated washing and filtering, dry in an oven at 120℃ overnight.

[0042] Step 2: Calcine the cleaned catalyst in a 5% O2 / 95% N2 atmosphere with a gas flow rate of 200 mL / min and a heating rate of 10℃ / min to reach 120℃. Maintain this temperature for 30 min to remove moisture and replace the overall atmosphere in the furnace. Then, turn off the gas flow and maintain a static gas atmosphere. Heat the catalyst to 350℃ at a rate of 5℃ / min and allow it to cool naturally for 2 hours. Small-scale combustion may occur on the support, with the surface turning white or burning to ash.

[0043] Step 3: Dissolve 0.0354 g of trichloroisocyanuric acid in 0.1 mol / L hydrochloric acid solution, then immerse 2.000 g of deactivated catalyst in the solution. Seal the mixture with a plastic film and place it in a 70°C water bath for 12 hours. Afterward, poke holes in the plastic film to allow slow evaporation of the dissolved solvent. Once the solvent has completely evaporated, transfer the sample to a 120°C oven overnight to obtain regenerated catalyst-3. The catalyst was then used in the acetylene hydrochlorination reaction at an acetylene volume hourly space velocity (HHSV) of 180 h⁻¹. −1 Under the conditions of a reaction temperature of 180℃ and a hydrogen chloride to acetylene feed ratio of 1.2, the reaction was initiated by introducing acetylene after activation with hydrogen chloride for 60 min in a nitrogen atmosphere. The highest acetylene conversion rate of the regenerated catalyst-3 was 62%, and after 24 hours of reaction, the acetylene conversion rate was 58%, a decrease of 4%. The selectivity for vinyl chloride was greater than 99%, and the performance was as follows. Figure 5 As shown.

[0044] Comparative Example 4: Method for regenerating the catalyst obtained in Example 1 Step 1: Take 5,000 g of deactivated catalyst and add 40 mL of N,N dimethylformamide. Stir magnetically at 100-200 rpm for 15 min. After washing and filtering, add solvent again and ultrasonically clean for 30 min. After repeated washing and filtering, dry in an oven at 120℃ overnight.

[0045] Step 2: The cleaned catalyst was calcined in an Ar atmosphere with a gas flow rate of 200 mL / min. The temperature was increased to 120℃ at a rate of 10℃ / min and maintained for 30 min to remove moisture and replace the overall atmosphere in the furnace. The temperature was then increased to 450℃ at a rate of 5℃ / min. After calcination for 2 hours, the temperature was allowed to drop naturally. No obvious combustion phenomenon was observed in the support.

[0046] Step 3: Dissolve 0.0708 g of trichloroisocyanuric acid in 0.1 mol / L hydrochloric acid solution, then immerse 2.000 g of deactivated catalyst in the solution. Seal the mixture with a plastic film and place it in a 70°C water bath for 12 hours. Afterward, poke holes in the plastic film to allow slow evaporation of the dissolved solvent. Once the solvent has completely evaporated, transfer the sample to a 120°C oven overnight to obtain regenerated catalyst-4. The catalyst was then used in the acetylene hydrochlorination reaction at an acetylene volume hourly space velocity (HHSV) of 180 h⁻¹. −1 Under the conditions of a reaction temperature of 180℃ and a hydrogen chloride to acetylene feed ratio of 1.2, the reaction was initiated by introducing acetylene after activation with hydrogen chloride for 60 min in a nitrogen atmosphere. The highest acetylene conversion rate of the regenerated catalyst-4 was 66%, and after 24 hours of reaction, the acetylene conversion rate was 64%, a decrease of 2%. The selectivity for vinyl chloride was greater than 99%, and the performance was as follows. Figure 6 As shown.

[0047] Comparative Example 5: Method for regenerating the catalyst obtained in Example 1 Step 1: Take 5,000 g of deactivated catalyst and add it to 40 mL of dichloromethane. Stir magnetically at 100-200 rpm for 15 min. After washing and filtering, add solvent again and ultrasonically clean for 30 min. After repeated washing and filtering, dry in an oven at 120℃ overnight.

[0048] Step 2: The cleaned catalyst was calcined in an Ar atmosphere with a gas flow rate of 200 mL / min. The temperature was increased to 120°C at a rate of 10°C / min and maintained for 30 min to remove moisture and replace the overall atmosphere in the furnace. The temperature was then increased to 500°C at a rate of 5°C / min. After calcination for 2 hours, the temperature was allowed to drop naturally. No obvious combustion phenomenon was observed in the support.

[0049] Step 3: Dissolve 0.0354 g of trichloroisocyanuric acid in a 6 mol / L hydrochloric acid solution, then immerse 2.000 g of deactivated catalyst in the solution. Seal the mixture with a plastic film and place it in a 70°C water bath for 12 hours. Afterward, poke holes in the plastic film to allow slow evaporation of the dissolved solvent. Once the solvent has completely evaporated, transfer the sample to a 120°C oven overnight to obtain regenerated catalyst-5. The catalyst was then used in the hydrochlorination of acetylene at an acetylene volume hourly space velocity (HHSV) of 180 h⁻¹. −1 Under the conditions of a reaction temperature of 180℃ and a hydrogen chloride to acetylene feed ratio of 1.2, the reaction was initiated by introducing acetylene after activation with hydrogen chloride for 60 min in a nitrogen atmosphere. The highest acetylene conversion rate of the regenerated catalyst-5 was 65%, and after 24 hours of reaction, the acetylene conversion rate was 60%, a decrease of 5%. The selectivity for vinyl chloride was greater than 99%, and the performance was as follows. Figure 7 As shown.

[0050] The main differences and conclusions of the experimental data for the above five comparative examples are shown in the table below: Differential data Regeneration Comparative Example 1 (Optimal) Regeneration Comparative Example 2 Regeneration Comparative Example 3 Regeneration Comparative Example 4 Regeneration Comparative Example 5 Cleaning solvent 20ml isopropanol + 20ml acetonitrile (mixed solvent) 40ml ethyl acetate (single solvent) 40ml acetonitrile (single solvent) 40ml N,N-dimethylformamide (single solvent) 40ml dichloromethane (single solvent) Calcination atmosphere Argon atmosphere static air atmosphere <![CDATA[Static 5% O2 / 95% N2 atmosphere]]> Argon atmosphere Argon atmosphere Calcination final temperature 600 ℃ 300 ℃ 350 ℃ 450 ℃ 500 ℃ Calcination / holding time 2 h 2 h 2 h 2 h 2 h TCCA dosage 0.0354g 0.0177g (half of Comparative Example 1) 0.0354g 0.0708g (twice that of Comparative Example 1) 0.0354 g hydrochloric acid concentration 1 mol / L 1 mol / L 0.1 mol / L (1 / 10 of the comparative example) 0.1 mol / L (1 / 10 of the comparative example) 6 mol / L Core performance: Acetylene conversion rate 72% 74% 62% 66% 65% Acetylene conversion rate after 24 hours 67% 65% 58% 64% 60% The above scheme demonstrates that this application achieves the reconstruction of Au with high electron density and structural stability on the surface of a calcined and regenerated gold-based catalyst without introducing external strong oxidants (such as potassium permanganate or nitric acid). This is achieved by utilizing the dual functions of TCCA, which possess both oxidizing and coordinating properties, and through precise control of a four-stage process involving cleaning, calcination, impregnation, and slow evaporation. 3+ / Au +–TCCA coordination active center; inert gas calcination effectively removes carbon deposits generated by side reactions while protecting the support structure; a 70°C water bath ensures the thermodynamic feasibility and kinetic controllability of the oxidation reaction; the plastic film sealing and perforation design effectively regulates the solvent evaporation path and rate; ultimately, the regenerated catalyst recovers more than 65% of the acetylene conversion rate in the acetylene hydrochlorination reaction (an improvement of more than 40 percentage points compared to the deactivated state, with a decrease in acetylene conversion rate within 5 percentage points after 24 hours, showing relative stability) and maintains a selectivity of 99%, significantly extending the industrial service life of the catalyst and reducing the cost of using precious metals. The above solution solves the core problem of "complex re-oxidation of gold species in regeneration" pointed out in the background technology—that is, how to achieve a reversible, efficient, and uniform re-oxidation and re-coordination process of reduced gold without damaging the microporous structure of the carbon support, without inducing the dissolution of precious metals, and without causing secondary pollution.

[0051] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A gold-based catalyst for the hydrochlorination of acetylene, wherein the catalyst is prepared by impregnation using microporous activated carbon as a carrier, with the addition of a gold active component, a copper auxiliary agent, and an organic ligand, characterized in that... The gold active component is HAuCl4, the copper auxiliary is CuCl2·2H2O, and the organic ligand is trichloroisocyanuric acid (TCCA).

2. The method for preparing the gold-based catalyst for the acetylene hydrochlorination reaction according to claim 1, comprising the following steps in sequence: activated carbon pretreatment → preparation of a mixed impregnation solution containing gold active components, copper additives, and organic ligands → equal-volume impregnation → drying → finished catalyst, characterized in that, In the preparation method, the copper additive is added according to the molar ratio of Cu to Au of (5~30):1, and the organic ligand is added according to the molar ratio of trichloroisocyanuric acid (TCCA) to Au of (5~20):

1.

3. The method for regenerating the gold-based catalyst for the acetylene hydrochlorination reaction according to claim 1, characterized in that, The regeneration method includes the following steps: (1) Solvent cleaning: The deactivated catalyst is cleaned with solvent to remove some surface impurities; (2) Calcination activation: The cleaned catalyst is calcined at high temperature under an inert atmosphere to efficiently remove carbon deposits; (3) Catalyst regeneration: The calcined and activated catalyst is immersed in a hydrochloric acid solution containing trichloroisocyanuric acid (TCCA), and the solvent is slowly evaporated and dried by water bath heating to obtain the regenerated catalyst.

4. The method for regenerating the gold-based catalyst for the acetylene hydrochlorination reaction according to claim 3, characterized in that, The solvent cleaning process in step (1) consists of stirring, sonication, filtration and drying.

5. The method for regenerating the gold-based catalyst for the acetylene hydrochlorination reaction according to claim 3 or 4, characterized in that, The solvent includes one or more of ethanol, isopropanol, dichloromethane, acetonitrile, ethyl acetate, and N,N-dimethylformamide.

6. The method for regenerating the gold-based catalyst for the acetylene hydrochlorination reaction according to claim 3, characterized in that, In step (2), the inert gas flow rate is 200 mL / min and the calcination temperature is 450~600℃.

7. The method for regenerating the gold-based catalyst for the acetylene hydrochlorination reaction according to claim 3 or 6, characterized in that, The calcination process involves first raising the temperature to 120°C at a rate of 10°C / min and maintaining it for 30 minutes to remove moisture. Then, the overall atmosphere inside the furnace is replaced, followed by raising the temperature to 600°C at a rate of 5°C / min. After calcining for 2 hours, the temperature is allowed to drop naturally.

8. The method for regenerating the gold-based catalyst for the acetylene hydrochlorination reaction according to claim 3, characterized in that, In step (3), the ratio of trichloroisocyanuric acid to gold during the ligand re-addition process is (5-25):

1.

9. The method for regenerating the gold-based catalyst for the acetylene hydrochlorination reaction according to claim 3 or 8, characterized in that, The concentration of hydrochloric acid used in step (3) is 0.1-6 mol / L.

10. The method for regenerating the gold-based catalyst for the acetylene hydrochlorination reaction according to claim 3 or 8, characterized in that, During the ligand addition process, the calcined catalyst needs to be immersed in a solution containing trichloroisocyanuric acid (TCCA). The mixture is then sealed with a plastic film and placed in a water bath at 70°C. After 12 hours, holes are punched in the surface of the plastic film to allow the solvent to evaporate slowly. Once the solvent has completely evaporated, the sample is transferred to an oven at 120°C to dry.

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