A gold-polymer catalyst for the hydrochlorination of acetylene, its preparation method and use

Abstract

The application discloses a kind of gold-polymer catalyst for acetylene hydrochlorination reaction and its preparation method and application, gold-containing salt and polymer are mixed in solvent and reacted, then activated carbon carrier is added to the reaction system, dried, heat treated, to obtain gold-polymer catalyst for acetylene hydrochlorination reaction.The application constructs stable gold-polymer system on the surface of activated carbon carrier, and is applied in the reaction of acetylene hydrochlorination.Gold-polymer structure is stable, and is not easy to be destroyed or lost in the reaction process;Gold-polymer itself has nitrogen, oxygen and other heteroatoms, and its own pore structure can provide anchoring site for active center, and greatly reduce the agglomeration of active center in the reaction process;Polymer itself can realize electron transport, so that the active center is always in a higher valence state in the reaction process;The catalyst has good stability and catalytic activity in the reaction of acetylene hydrochlorination at high and low space velocity.

Description

Technical Field

[0001] This invention belongs to the field of catalyst preparation technology, specifically relating to a gold-polymer catalyst for the hydrochlorination reaction of acetylene, its preparation method, and its application. Background Technology

[0002] Polyvinyl chloride (PVC), as the third most widely used polymer, has extensive and important applications in the construction and building materials industry, as well as the packaging, electrical, and apparel industries due to its high resistance to light and chemicals. Vinyl chloride monomer (VCM) is the main chemical intermediate in the synthesis of PVC. Due to my country's energy characteristics of "abundant coal, scarce oil, and limited gas," the calcium carbide acetylene method accounts for over 80% of the production of vinyl chloride monomer. Currently, the most commonly used catalyst in the calcium carbide acetylene method is activated carbon-supported mercuric chloride (HgCl2). Calculations show that producing one ton of PVC requires 1.02-1.41 kg of HgCl2 catalyst, resulting in an annual mercury consumption exceeding 600 tons. Furthermore, approximately 25% of the HgCl2 is lost during the reaction process, causing irreversible environmental pollution and posing risks to human health. With the signing of the Minamata Convention, the pollution problem caused by the use of mercury catalysts urgently needs to be addressed, making the research and development of mercury-free catalysts to replace mercury-based catalysts imperative. The Hutchings team at Cardiff University in the UK clearly pointed out in their paper that catalysts with gold as the active center have the highest theoretical activity (Science 355, 1399–1403 (2017)). Therefore, gold-based catalysts have shown the greatest potential in replacing Hg-based catalysts. Compared with catalysts with other metals as the active center, gold catalysts mainly have two major problems to solve: First, gold in the acetylene hydrochlorination reaction is usually most active in the trivalent form, while the 0-valent form has almost no activity. Because the redox potential of trivalent gold is very high, reaching 1.50V, it is easily reduced and loses its activity in a strongly reducing atmosphere containing acetylene. Second, gold is expensive compared to other metals. Considering cost-effectiveness, the gold content in the catalyst is usually 0.05–0.5 wt%. Due to the low metal content, the activity of gold catalysts is often low. In order to realize the industrialization of gold catalysts, improving the stability and activity of the catalyst under low loading conditions is the focus of future research.

[0003] To address the aforementioned bottlenecks in gold catalysts, researchers have conducted extensive work on strategies such as modifying the support, adding other metals, and ligand protection to suppress deactivation and improve the activity and stability of gold-based catalysts. Because trivalent gold ions have a relatively large effective nuclear charge radius and strong polarization ability towards ligands, thereby enhancing the coordination between the central atom and the ligand, using different ligands to protect the active center trivalent gold is the most effective strategy.

[0004] Patent CN 105148989 A uses imidazole-based ionic liquids as ligands; CN 109847802 A uses a class of small molecule ligands containing heteroatoms. Although the use of these two types of ligands significantly improves the activity and stability of the gold catalyst, stability tests revealed that the small molecule ligands are lost with increasing reaction time, leading to the aggregation and continuous reduction of trivalent gold ions. Summary of the Invention

[0005] To address the problem that existing technologies fail to meet the lifetime and activity requirements of gold catalysts for industrial production due to unstable ligand structures, the present invention aims to provide a gold-polymer catalyst for the hydrochlorination of acetylene, its preparation method, and its application. This method prepares the gold catalyst by mixing gold salts, polymers, and activated carbon supports. The prepared catalyst, when applied to the hydrochlorination of acetylene to synthesize vinyl chloride, exhibits high activity and high stability even at high acetylene space velocities.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] A method for preparing a gold-polymer catalyst for the hydrochlorination reaction of acetylene includes the following steps:

[0008] Gold salts and polymers are mixed and reacted in a solvent, then activated carbon support is added to the reaction system, followed by drying and heat treatment to obtain a gold-polymer catalyst for the hydrochlorination of acetylene.

[0009] Furthermore, the gold salt is one of chloroauric acid tetrahydrate, dimethyl (acetylacetone) gold, sodium chloroaurate, and gold chloride.

[0010] Furthermore, the polymer is a nitrogen- or oxygen-containing heteroatom polymer with a degree of polymerization not exceeding 30,000.

[0011] Furthermore, the polymer is one of polyvinyl alcohol, polyacrylonitrile, and polyacrylamide; the activated carbon carrier is 20-60 mesh coconut shell carbon.

[0012] Furthermore, the mass ratio of the gold salt, polymer, and activated carbon carrier is (0.001-0.01):(0.01-0.1):(0.89-0.989).

[0013] Furthermore, the temperature of the mixed reaction is 20–80°C, and the reaction time is 4–24 h.

[0014] Furthermore, the heat treatment conditions are: temperature of 150–300°C, time of 1–24 h, and atmosphere of inert atmosphere.

[0015] Furthermore, the gas source for the inert atmosphere is either nitrogen or argon.

[0016] A gold-polymer catalyst for the hydrochlorination of acetylene, prepared according to the preparation method described above.

[0017] The application of the gold-polymer catalyst for the acetylene hydrochlorination reaction as described above involves loading the gold-polymer catalyst into a fixed-bed reactor, and then introducing hydrogen chloride and acetylene into the fixed-bed reactor, with an acetylene space velocity of 30–2000 h⁻¹. -1 The reaction temperature is 90–300℃, and the volume ratio of acetylene to hydrogen chloride is 1:1–5.

[0018] Furthermore, the volume hourly space velocity (VHSV) of acetylene is 30–180 h⁻¹. -1 The reaction temperature is 140–180℃, and the volume ratio of acetylene to hydrogen chloride is 1:1.1–1.2.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] This invention constructs a stable gold-polymer system on the surface of an activated carbon support and applies it to the hydrochlorination of acetylene. First, the gold-polymer has a stable structure, making it less prone to structural damage or loss during the reaction. Second, the presence of heteroatoms such as nitrogen and oxygen, along with its porous structure, provides anchoring sites for the active centers and significantly reduces their aggregation during the reaction. Finally, the polymer itself enables electron transport, ensuring that the active centers remain in a high valence state throughout the reaction. Based on these advantages of the gold-polymer catalytic system, the prepared catalysts exhibit good stability and catalytic activity at both high and low space velocities.

[0021] The gold-polymer catalyst prepared in this invention exhibits high activity and stability in the acetylene hydrochlorination reaction, with an acetylene conversion rate of 83-92% after 1 hour and 84-91% after 24 hours, and a vinyl chloride selectivity of >98%. Detailed Implementation

[0022] The present invention will be described in detail below through embodiments. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0023] This invention provides a method for preparing a gold-polymer catalyst for the hydrochlorination reaction of acetylene, comprising the following steps:

[0024] First, the gold salt and polymer are mixed and reacted in a solvent. Then, an activated carbon support is added to the reaction system, and the mixture is dried. Finally, the obtained sample is heat-treated under certain conditions to obtain the gold-polymer catalyst for the acetylene hydrochlorination reaction.

[0025] Preferably, the gold salt is one of chloroauric acid tetrahydrate, dimethyl (acetylacetone) gold, sodium chloroaurate, and gold chloride.

[0026] Preferably, the polymer is a polymer containing nitrogen or oxygen heteroatoms;

[0027] Preferably, the polymer is one of polyvinyl alcohol (molecular weight 13,000-23,000), polyacrylonitrile (molecular weight 25,000-30,000), and polyacrylamide (molecular weight 25,000-30,000).

[0028] Preferably, the degree of polymerization of the polymer is low, i.e., not exceeding 30,000;

[0029] Preferably, the activated carbon carrier is 20-60 mesh coconut shell charcoal. The activated carbon carrier used in this invention is an industrial-grade carrier.

[0030] Preferably, the mass ratio of the gold salt, polymer, and activated carbon carrier is (0.001-0.01):(0.01-0.1):(0.89-0.989).

[0031] Preferably, the mixing reaction can be carried out at 20–80°C, and the reaction time can be controlled between 4 and 24 hours.

[0032] Preferably, the heat treatment conditions are: the heat treatment temperature is 150-300℃, the time can be controlled between 1 and 24 hours, and the heat treatment atmosphere is an inert atmosphere.

[0033] Furthermore, the gas source for the inert atmosphere is either nitrogen or argon.

[0034] This invention provides a gold-polymer catalyst for the hydrochlorination of acetylene, the specific method of which is as follows:

[0035] The gas-phase reaction is carried out in a fixed-bed reactor;

[0036] The gold-polymer catalyst was packed into a fixed-bed reactor, and hydrogen chloride and acetylene were introduced into the reactor. The acetylene space velocity could be controlled between 30 and 2000 h⁻¹. -1 The reaction temperature can be controlled between 90 and 300°C, and the volume ratio of acetylene to hydrogen chloride is 1:1 to 5.

[0037] Preferably, the acetylene volume hourly space velocity can be controlled within the range of 30–180 h⁻¹. -1 .

[0038] Preferably, the reaction temperature is controlled at 140–180°C.

[0039] Preferably, the volume ratio of acetylene to hydrogen chloride is 1:1.1 to 1.2.

[0040] Example 1

[0041] A method for preparing a metal complex catalyst for the hydrochlorination of acetylene is as follows:

[0042] First, the gold salt and polymer are mixed and reacted in a solvent. Then, an activated carbon support is added to the reaction system, and the mixture is dried. Finally, the obtained sample is heat-treated under certain conditions to obtain the gold-polymer catalyst for the acetylene hydrochlorination reaction.

[0043] The gold-containing salt is gold chloride.

[0044] The polymer is polyvinyl alcohol with a molecular weight of 13,000-23,000.

[0045] The activated carbon carrier is coconut shell carbon with a mesh size of 20-60.

[0046] The mass ratio of the gold salt, polymer, and activated carbon carrier is 0.01:0.05:0.94.

[0047] The aforementioned mixed reaction can be carried out at 40°C, and the reaction time can be controlled within 8 hours.

[0048] The heat treatment conditions are as follows: the heat treatment temperature is 150℃, the time can be controlled within 8 hours, and the heat treatment atmosphere is nitrogen.

[0049] Two mL of the prepared gold-polymer catalyst was packed into a fixed-bed reactor, and hydrogen chloride was introduced into the reactor. The acetylene space velocity could be controlled at 1200 h⁻¹. -1 The reaction temperature can be controlled at 180℃, and the volume ratio of acetylene to hydrogen chloride is 1:1.15.

[0050] The acetylene conversion rate and vinyl chloride selectivity were calculated for the first hour and the 24th hour, respectively, and the results are shown in Table 1.

[0051] The preparation process of Examples 2-9 is the same as that of Example 1, and the data are shown in Table 1.

[0052] Comparative Example 1

[0053] According to the loading amounts and ratios listed in Table 1, gold chloride was first reacted in a solvent, then activated carbon support was added to the reaction system, followed by drying. The resulting sample was then heat-treated under certain conditions to obtain the gold-polymer catalyst.

[0054] Two mL of the prepared catalyst was placed in a fixed-bed reactor. The volume ratio of acetylene to hydrogen chloride was 1:1.15, the reaction temperature was 180 °C, and the volume hourly space velocity (VHSV) of acetylene was 1200 h⁻¹. -1 The reaction was carried out for 24 hours. The acetylene conversion rate and vinyl chloride selectivity were calculated at the 1st hour and the 24th hour, respectively. The results are shown in Table 1.

[0055] Comparative Example 2

[0056] According to the loading amounts and ratios listed in Table 1, polyvinyl alcohol was first reacted in a solvent, then activated carbon support was added to the reaction system, followed by drying. The resulting sample was then heat-treated under certain conditions to obtain the gold-polymer catalyst.

[0057] Two mL of the prepared catalyst was placed in a fixed-bed reactor. The volume ratio of acetylene to hydrogen chloride was 1:1.15, the reaction temperature was 180 °C, and the volume hourly space velocity (VHSV) of acetylene was 1200 h⁻¹. -1 The reaction was carried out for 24 hours. The acetylene conversion rate and vinyl chloride selectivity were calculated at the 1st hour and the 24th hour, respectively. The results are shown in Table 1.

[0058] Example 10

[0059] Catalyst No. 10 prepared in Example 1 was subjected to a 1000-hour stability test according to the above steps. Reaction conditions: T = 180℃, V HCl / V C2H2 =1.15, GHSV=180h -1 The results showed that the conversion rate of acetylene decreased from 99% to 92%, while the selectivity of vinyl chloride remained above 99%, indicating good stability.

[0060] Table 1. Preparation conditions of gold-polymer catalysts and evaluation results of acetylene hydrochlorination reaction.

[0061]

[0062]

[0063] As can be seen from Table 1, the acetylene conversion rate of the catalyst prepared in the embodiments of the present invention is 83-92% after 1 hour of acetylene hydrochlorination reaction, and 84-91% after 24 hours of reaction, with a vinyl chloride selectivity >98%.

[0064] Example 11

[0065] A method for preparing a metal complex catalyst for the hydrochlorination of acetylene is as follows:

[0066] First, the gold salt and polymer are mixed and reacted in a solvent. Then, an activated carbon support is added to the reaction system, and the mixture is dried. Finally, the obtained sample is heat-treated under certain conditions to obtain the gold-polymer catalyst for the acetylene hydrochlorination reaction.

[0067] The gold-containing salt is gold chloride.

[0068] The polymer in question is polyvinyl alcohol.

[0069] The activated carbon carrier is coconut shell carbon with a mesh size of 20-60.

[0070] The mass ratio of the gold salt, polymer, and activated carbon carrier is 0.001:0.01:0.89.

[0071] The aforementioned mixed reaction can be carried out at 20°C, and the reaction time can be controlled within 24 hours.

[0072] The heat treatment conditions are as follows: the heat treatment temperature is 300℃, the time can be controlled within 1 hour, and the heat treatment atmosphere is nitrogen.

[0073] Two mL of the prepared gold-polymer catalyst was packed into a fixed-bed reactor, and hydrogen chloride was introduced into the reactor. The acetylene space velocity could be controlled at 500 h⁻¹. -1 The reaction temperature can be controlled at 90℃, and the volume ratio of acetylene to hydrogen chloride is 1:1.1.

[0074] Example 12

[0075] A method for preparing a metal complex catalyst for the hydrochlorination of acetylene is as follows:

[0076] First, the gold salt and polymer are mixed and reacted in a solvent. Then, an activated carbon support is added to the reaction system, and the mixture is dried. Finally, the obtained sample is heat-treated under certain conditions to obtain the gold-polymer catalyst for the acetylene hydrochlorination reaction.

[0077] The gold-containing salt is gold chloride.

[0078] The polymer in question is polyvinyl alcohol.

[0079] The activated carbon carrier is coconut shell carbon with a mesh size of 20-60.

[0080] The mass ratio of the gold salt, polymer, and activated carbon carrier is 0.01:0.05:0.9.

[0081] The aforementioned mixed reaction can be carried out at 80°C, and the reaction time can be controlled within 4 hours.

[0082] The heat treatment conditions are as follows: the heat treatment temperature is 190℃, the time can be controlled within 20 hours, and the heat treatment atmosphere is nitrogen.

[0083] Two mL of the prepared gold-polymer catalyst was loaded into a fixed-bed reactor, and hydrogen chloride was introduced into the reactor. The acetylene space velocity could be controlled at 30 h⁻¹. -1 The reaction temperature can be controlled at 300℃, and the volume ratio of acetylene to hydrogen chloride is 1:3.5.

[0084] Example 13

[0085] A method for preparing a metal complex catalyst for the hydrochlorination of acetylene is as follows:

[0086] First, the gold salt and polymer are mixed and reacted in a solvent. Then, an activated carbon support is added to the reaction system, and the mixture is dried. Finally, the obtained sample is heat-treated under certain conditions to obtain the gold-polymer catalyst for the acetylene hydrochlorination reaction.

[0087] The gold-containing salt is gold chloride.

[0088] The polymer in question is polyvinyl alcohol.

[0089] The activated carbon carrier is coconut shell carbon with a mesh size of 20-60.

[0090] The mass ratio of the gold salt, polymer, and activated carbon carrier is 0.005:0.03:0.989.

[0091] The aforementioned mixed reaction can be carried out at 50°C, and the reaction time can be controlled within 15 hours.

[0092] The heat treatment conditions are as follows: the heat treatment temperature is 250℃, the time can be controlled within 15 hours, and the heat treatment atmosphere is argon.

[0093] Two mL of the prepared gold-polymer catalyst was packed into a fixed-bed reactor, and hydrogen chloride was introduced into the reactor. The acetylene space velocity could be controlled at 2000 h⁻¹. -1 The reaction temperature can be controlled at 140℃, and the volume ratio of acetylene to hydrogen chloride is 1:2.

[0094] Example 14

[0095] A method for preparing a metal complex catalyst for the hydrochlorination of acetylene is as follows:

[0096] First, the gold salt and polymer are mixed and reacted in a solvent. Then, an activated carbon support is added to the reaction system, and the mixture is dried. Finally, the obtained sample is heat-treated under certain conditions to obtain the gold-polymer catalyst for the acetylene hydrochlorination reaction.

[0097] The gold-containing salt is gold chloride.

[0098] The polymer in question is polyvinyl alcohol.

[0099] The activated carbon carrier is coconut shell carbon with a mesh size of 20-60.

[0100] The mass ratio of the gold salt, polymer, and activated carbon carrier is 0.003:0.08:0.95.

[0101] The aforementioned mixed reaction can be carried out at 30°C, and the reaction time can be controlled within 20 hours.

[0102] The heat treatment conditions are as follows: the heat treatment temperature is 150℃, the time can be controlled within 24 hours, and the heat treatment atmosphere is nitrogen.

[0103] Two mL of the prepared gold-polymer catalyst was packed into a fixed-bed reactor, and hydrogen chloride was introduced into the reactor. The acetylene space velocity could be controlled at 1000 h⁻¹. -1 The reaction temperature can be controlled at 250℃, and the volume ratio of acetylene to hydrogen chloride is 1:3.

[0104] Example 15

[0105] A method for preparing a metal complex catalyst for the hydrochlorination of acetylene is as follows:

[0106] First, the gold salt and polymer are mixed and reacted in a solvent. Then, an activated carbon support is added to the reaction system, and the mixture is dried. Finally, the obtained sample is heat-treated under certain conditions to obtain the gold-polymer catalyst for the acetylene hydrochlorination reaction.

[0107] The gold-containing salt is gold chloride.

[0108] The polymer in question is polyvinyl alcohol.

[0109] The activated carbon carrier is coconut shell carbon with a mesh size of 20-60.

[0110] The mass ratio of the gold salt, polymer, and activated carbon carrier is 0.007:0.1:0.93.

[0111] The aforementioned mixed reaction can be carried out at 70°C, and the reaction time can be controlled within 10 hours.

[0112] The heat treatment conditions are as follows: the heat treatment temperature is 270℃, the time can be controlled within 10 hours, and the heat treatment atmosphere is nitrogen.

[0113] Two mL of the prepared gold-polymer catalyst was packed into a fixed-bed reactor, and hydrogen chloride was introduced into the reactor. The acetylene space velocity could be controlled at 1500 h⁻¹. -1 The reaction temperature can be controlled at 170℃, and the volume ratio of acetylene to hydrogen chloride is 1:5.

[0114] The above description is only of the preferred embodiment of the present invention and should not be construed as limiting the scope of the claims. The present invention is not limited to the above embodiments, and variations in its specific structure are permitted. All variations made within the scope of the independent claims of the present invention are also within the scope of protection of the present invention.

[0115] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

Claims

1. A method for preparing a gold-polymer catalyst for the hydrochlorination of acetylene, characterized in that, The method comprises the following steps: The gold-containing salt and the nitrogen or oxygen-containing polymer with a polymerization degree of less than 30000 are mixed and reacted in a solvent, 20-60 mesh coconut shell carbon is added as an activated carbon carrier, and then drying and heat treatment are performed to obtain a gold-polymer catalyst for the hydrochlorination of acetylene. The gold-containing salt is one of chloroauric acid tetrahydrate, dimethyl (acetylacetone) gold, sodium chloroaurate and gold chloride. The polymer is one of polyvinyl alcohol, polyacrylonitrile and polyacrylamide. The heat treatment is performed at a temperature of 150-300 DEG C in an inert atmosphere.

2. The method for preparing a gold-polymer catalyst for the hydrochlorination of acetylene according to claim 1, characterized by, The mass ratio of the gold-containing salt, the polymer and the activated carbon carrier is (0.001-0.01):(0.01-0.1):(0.89-0.989).

3. The method for preparing a gold-polymer catalyst for hydrochlorination of acetylene according to claim 1, characterized by, The mixing and reaction are performed at a temperature of 20-80 DEG C for 4-24 hours.

4. The method for preparing a gold-polymer catalyst for hydrochlorination of acetylene according to claim 1, characterized by, The heat treatment is performed for 1-24 hours.

5. A gold-polymer catalyst for the hydrochlorination of acetylene, which is prepared by the preparation method according to any one of claims 1-4.

6. Use of a gold-polymer catalyst for the hydrochlorination of acetylene as claimed in claim 5, characterized in that, The gold-polymer catalyst is loaded in a fixed bed reactor, and hydrogen chloride and acetylene are introduced into the fixed bed reactor, the acetylene space velocity being 30-2000 h -1 -1, the reaction temperature being 90-300 DEG C, and the volume ratio of acetylene to hydrogen chloride being 1:1-5.

7. Use according to claim 6, characterized in that, The acetylene volume space velocity is 30-180 h -1 The reaction temperature is 140-180°C, and the volume ratio of acetylene to hydrogen chloride is 1:1.1-1.2.

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