Method for preparing vinyl chloride through electro-catalysis of 1, 2-dichloroethane

Abstract

The invention discloses a method for preparing vinyl chloride by electrocatalytic dechlorination of 1, 2-dichloroethane, a working electrode of the method takes a metal oxide as a catalyst, and the metal oxide is selected from at least one of the following metal oxides: Pd, Mn, Fe, Co, Ni, Cu, Ru and Mo. According to the invention, the metal oxide powder is used as the electrocatalyst, the catalyst is coated on the electrode material to prepare the working electrode, the working electrode is applied to electrocatalytic dechlorination reaction of 1, 2-dichloroethane, vinyl chloride can be generated at high selectivity at room temperature, a new way is opened up for production of vinyl chloride by electrocatalytic dechlorination, and the method has wide application prospect. And a green and low-cost solution is provided for efficient synthesis of vinyl chloride.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical catalysis technology, specifically relating to a method for preparing vinyl chloride from 1,2-dichloroethane by electrocatalysis. Background Technology

[0002] With the continuous growth of economies and the booming industrial development of many countries around the world, the conflict between human activities and environmental pollution has become increasingly severe. Finding a sustainable development path is of paramount importance. Polyvinyl chloride (PVC), as one of the three most widely produced polymers along with polyethylene and polypropylene, is an extremely widely used plastic due to its advantages such as corrosion resistance, excellent insulation, and high mechanical strength. Therefore, global demand for vinyl chloride monomer (VCM) of PVC has been increasing year by year. The resulting environmental problems are becoming increasingly serious, making it essential to find a new method for producing vinyl chloride with low or even zero emissions.

[0003] Industrially, vinyl chloride is mainly synthesized via the acetylene method, the ethylene method, and the ethane method, with the ethane method still in the exploratory stage. The acetylene method directly produces vinyl chloride by reacting acetylene with hydrogen chloride. my country's unique energy structure provides ideal conditions for large-scale production of vinyl chloride through acetylene hydrochlorination. However, the environmental problems caused by the process and the search for alternative industrial mercury-based catalysts to replace environmental pollution are the biggest challenges currently facing this technology. The ethylene method has two routes: ethylene chlorination and ethylene oxychlorination. Ethylene oxychlorination involves reacting ethylene with oxygen and hydrogen chloride to prepare DCE (1,2-dichloroethane), followed by the thermal cracking of DCE at high temperatures (450-550℃) to obtain VCM. During the cracking process, due to the high operating temperature, coke deposits in the tubular reactor, reducing the flow area within the reactor, increasing mass transfer resistance, and wasting energy, causing serious environmental problems. Here, we propose a new method for the electrocatalytic dehydrochlorination of 1,2-dichloroethane to produce vinyl chloride.

[0004] In the electrocatalytic dechlorination of DCE, research on the electrocatalytic dechlorination of DCE mainly focuses on the cathode reduction to ethylene (… The stepwise removal of chlorine atoms is achieved through a β-elimination mechanism, with near 100% selectivity for ethylene at constant potential electrolysis, while the selectivity for vinyl chloride at other potentials is only in the single digits. Jiao Ning et al. [Yujie Liang, Fengguirong Lin, Yeerlan Adeli, Rui Jin, Prof. Ning Jiao. Efficient Electrocatalysis for the Preparation of (Hetero)aryl Chlorides and VinylChloride with 1,2-Dichloroethane. Angewandte Chemie International Edition, Volume 58, Issue 14, pp. 4566-4570] reported a bifunctional electrocatalytic strategy in which, while dechlorinating hydrogen chloride at the cathode, Cl- ionized with HCl is simultaneously removed. - Using tetrabutylammonium tetrafluoroborate as the electrolyte, aryl chlorides were efficiently synthesized at the anolyte. With a graphite anode and cathode Pt plates at a constant current of 100 mA, VCM with 45% selectivity, ethylene with 53% selectivity, and small amounts of other components were obtained. With tetrabutylammonium hydroxide as the electrolyte, VCM with 48% selectivity, ethylene with 46% selectivity, 1,1-dichloroethylene with 5% selectivity, and other components with 1% selectivity were obtained. After dechlorinating the DCE, the chloride ions were reused at the anolyte to synthesize aryl chlorides. The cathode reaction did not produce a highly selective product on its own, which greatly hindered subsequent separation.

[0005] Based on this, the present invention proposes for the first time a method for preparing vinyl chloride by highly selective DCE electrocatalytic dechlorination at the cathode. Summary of the Invention

[0006] To address the technical problems of low selectivity of vinyl chloride in the electrocatalytic dechlorination reaction of 1,2-dichloroethane, which uses ethylene as the main reduction product, this invention provides a method for preparing vinyl chloride by electrocatalytic dechlorination of 1,2-dichloroethane, thereby significantly improving the selectivity of vinyl chloride.

[0007] The technical solution adopted in this invention will be described in detail below.

[0008] A method for electrocatalytically preparing vinyl chloride from 1,2-dichloroethane, wherein the working electrode of the method uses a metal oxide as a catalyst, and the metal oxide is selected from at least one oxide of the following metals: Pd, Mn, Fe, Co, Ni, Cu, Ru, Mo.

[0009] Preferably, the metal oxide is selected from one or a mixture of two or more of Co2O3, NiO, Fe2O3, MnO, and CuO, and more preferably from one or a mixture of two or more of NiO, Fe2O3, and MnO.

[0010] The metal oxides described in this invention can be commercially available or prepared by means of methods reported in existing literature. In some embodiments, the metal oxides are prepared by precipitation, specifically by the following steps: a metal salt solution and a precipitant solution are first mixed. The precipitant reacts with the metal ions to form an insoluble compound, driving the formation of a metal precipitate. After complete precipitation, the precipitate is separated, washed, dried, and calcined in air at 300-700°C (preferably 500-700°C, more preferably 600°C) to obtain metal oxide powder. The metal salts are generally water-soluble chlorides or nitrates, with palladium and ruthenium metal salts preferably being chlorides, and other metal salts preferably being nitrates. The precipitant can be one or more of sodium hydroxide, ammonia, sodium carbonate, sodium bicarbonate, ammonium carbonate, and oxalic acid. It is understood that the purpose of this invention is to precipitate the metal salts using a precipitant; therefore, the amount of precipitant added should be sufficient to just precipitate the metal salt or slightly exceed the amount required.

[0011] The working electrode of this invention comprises an electrode material and a catalyst uniformly dispersed on the electrode material. The electrode material is at least one selected from carbon paper, carbon cloth, nickel foam, and copper foam. Preferably, Nafion is also uniformly dispersed on the electrode material. Preferably, the catalyst loading on the working electrode is 0.2-5 mg / cm³. 2 For example, 0.5, 1, 1.5, 2, 5 mg / cm³ 2 The range between any one of them or any two of them.

[0012] The working electrode of this invention can be prepared using conventional methods. In some embodiments, the working electrode is prepared according to the following steps: preparing a catalyst slurry, then uniformly coating the catalyst slurry onto the electrode material, and drying to obtain the working electrode. In the preparation of the working electrode, the solvent for preparing the slurry can be selected from at least one of deionized water, acetone, ethanol, isobutanol, ethylene glycol, n-propanol, and isopropanol. In embodiments, the solvent can be a mixed solvent composed of equal volumes of deionized water, n-propanol, and ethylene glycol. During the preparation of the catalyst slurry, stirring, ultrasonication, or other techniques can be introduced as needed to promote the dispersion of the catalyst in the solvent. Preferably, when preparing the catalyst slurry, a Nafion solution is also added, and the feed ratio of the catalyst to the Nafion solution is calculated as a mass-volume ratio of catalyst to 5% Nafion solution of 1 mg: 10-30 μL, for example, any one or a range between 1 mg: 10 μL, 1 mg: 15 μL, 1 mg: 10-20 μL, 1 mg: 30 μL, etc. The Nafion solution can be a commercially available product, such as DuPont's 5% Nafion D520 or D521.

[0013] In some embodiments, the method for preparing vinyl chloride by electrocatalytic dechlorination of 1,2-dichloroethane is carried out in a single-chamber reaction cell, an H-type electrolytic cell, or a continuous electrolytic cell. The electrodes are selected from nickel foam, copper foam, Pt electrodes, or graphite electrodes. The electrolyte is a solution containing 1,2-dichloroethane and a supporting electrolyte. The solvent of the electrolyte is one of water, ethanol, dimethyl sulfoxide, and N,N-dimethylformamide. The supporting electrolyte is selected from sodium sulfate, potassium bicarbonate, potassium sulfate, and tetrabutylammonium hydroxide. Preferably, the solvent of the electrolyte is N,N-dimethylformamide, and the electrolyte is tetrabutylammonium hydroxide. More preferably, the concentration of tetrabutylammonium hydroxide in the electrolyte is 0.1-2 mol / L, and the concentration of 1,2-dichloroethane is 0.1-4 mol / L.

[0014] In some embodiments, the electrochemical reaction is carried out at room temperature, under constant current or constant potential conditions, with an electrochemical cathode potential of -5 to 0 V (relative to a saturated calomel electrode) and a constant current of 1 to 200 mA.

[0015] The catalyst obtained by this invention has good reactivity in the electrocatalytic dechlorination reaction of 1,2-dichloroethane, and the selectivity of vinyl chloride in the carbon-containing product can reach more than 99%.

[0016] Compared with the prior art, the present invention has the following beneficial effects: This invention uses metal oxide powder as an electrocatalyst. The working electrode is prepared by coating the catalyst onto the electrode material. This working electrode is applied to the electrocatalytic dechlorination reaction of 1,2-dichloroethane and can generate vinyl chloride with high selectivity at room temperature. This opens up a new route for the electrocatalytic dechlorination of hydrogen chloride to produce vinyl chloride and provides a green and low-cost solution for the efficient synthesis of vinyl chloride. Attached Figure Description

[0017] Figures 1 - 5 The following are gas chromatograms of the gaseous products prepared in Examples 1-5, in sequence. Detailed Implementation

[0018] The present invention will now be clearly and completely described in conjunction with embodiments thereof. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. It should be noted that the embodiments are only used for further invention of the present invention, but should not be construed as limiting the scope of protection of the present invention, which is not limited thereto in any way. Those skilled in the art can make some non-essential improvements and adjustments based on the above-described invention.

[0019] Unless otherwise specified in the embodiments of this invention, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained through conventional technical means or commercially available.

[0020] Example 1

[0021] Step 1: Dissolve 3.18 g Na2CO3 in 50 mL of deionized water to obtain a Na2CO3 solution. Weigh 5.82 g Co(NO3)2·6H2O and dissolve it in 50 mL of deionized water. While stirring, add the Na2CO3 solution dropwise to the Co(NO3)2 solution until complete precipitation. After complete precipitation, age for 6 h. Filter the precipitate using a vacuum filter. Wash it first with deionized water and then with anhydrous ethanol. Place the filter cake in a vacuum drying oven and dry it at 80 ℃ for 12 h to obtain a dry cobalt-based precursor precipitate. Place the precursor in a muffle furnace and heat it to 600 ℃ at 5 ℃ / min and hold for 3 h. After natural cooling, grind it to obtain Co2O3 powder.

[0022] Step 2: Preparation of the working electrode: Weigh 2 mg of Co2O3 powder and disperse it in a mixed solution of 60 μL each of n-propanol, ethylene glycol, and deionized water. Add 20 μL of DuPont 5% Nafion D520 solution and then ultrasonically disperse the mixture to obtain a catalyst slurry. Dry the carbon paper washed with deionized water under an infrared lamp (100 W). Then, coat the dried carbon paper with 100 μL of the uniformly dispersed catalyst slurry. 2The working electrode is obtained by re-drying the carbon cloth, wherein the catalyst loading is 1 mg / cm³. 2 .

[0023] Step 3: The prepared working electrode, silver / silver chloride electrode, Pt electrode, and a closed single-chamber electrolytic cell with an inlet and an outlet (located on opposite sides of the working electrode) are combined to form a three-electrode system. Using an N,N-dimethylformamide solution containing 0.1 mol / L tetrabutylammonium hydroxide as the solvent, an appropriate amount of 1,2-dichloroethane solute is added to prepare an electrolyte with a concentration of 0.1 mol / L 1,2-dichloroethane.

[0024] Step 4: Place the electrode sheet prepared in Step 2 into the electrolytic cell assembled in Step 3 for electrolysis. Perform the electrolysis reaction at room temperature using a potentiostatic method with an electrochemical workstation (V = -1.25 V). Vs . RHE) analysis and testing. Nitrogen gas was introduced at a rate of 1 mL / min during electrolysis. -1 The gas is introduced into the single-chamber electrolytic cell at a high speed through the inlet, and high-purity nitrogen is used as the carrier gas to carry the gases generated during electrolysis out of the electrolytic cell through the outlet. Gas chromatography is used to analyze the reaction gases at the outlet. Specifically, a Shimadzu GC-2010 Pro gas chromatograph equipped with a (ShimCap-PLOT Al2O3) capillary column and a flame ionization detector (FID) is used for detection. The products are separated by a capillary column with high-purity nitrogen as the carrier gas at 80 °C, a pressure of 61.5 kPa, and a flow rate of 1.5 mL / min, with a split ratio of 1.7, a detector temperature of 200 °C, a termination time of 16 min, and nitrogen as the make-up gas at a flow rate of 30 mL / min. The organic products show a selectivity of 93.54% for vinyl chloride, 6.31% for ethylene, and 0.15% for acetylene.

[0025] Example 2

[0026] Step 1: Dissolve 3.18 g Na2CO3 in 50 mL of deionized water to obtain a Na2CO3 solution. Weigh 5.82 g Ni(NO3)2·6H2O and dissolve it in 50 mL of deionized water. While stirring, add the Na2CO3 solution dropwise to the Co(NO3)2 solution until complete precipitation. After complete precipitation, age for 6 h. Filter the precipitate using a vacuum filter. Wash it first with deionized water and then with anhydrous ethanol. Place the filter cake in a vacuum drying oven and dry it at 80 ℃ for 12 h to obtain a dry nickel-based precursor precipitate. Place the precursor in a muffle furnace and heat it to 600 ℃ at 5 ℃ / min and hold for 3 h. After natural cooling, grind it to obtain NiO powder.

[0027] Step 2: Preparation of the working electrode: Weigh 2 mg of NiO powder and disperse it in a mixed solution of 60 μL each of n-propanol, ethylene glycol, and deionized water. Add 20 μL of DuPont 5% Nafion D520 solution, and then ultrasonically disperse to obtain a catalyst slurry. Dry the carbon paper after washing with deionized water under an infrared lamp (100 W). Then, coat the dried carbon paper with 100 μL of the uniformly dispersed catalyst slurry onto a 1 cm thick sheet. 2 The working electrode is obtained by re-drying the carbon cloth, wherein the catalyst loading is 1 mg / cm³. 2 .

[0028] Step 3: The prepared working electrode, silver / silver chloride electrode, Pt electrode, and a closed single-chamber electrolytic cell with an inlet and an outlet (located on opposite sides of the working electrode) are combined to form a three-electrode system. Using an N,N-dimethylformamide solution containing 0.1 mol / L tetrabutylammonium hydroxide as the solvent, an appropriate amount of 1,2-dichloroethane solute is added to prepare an electrolyte with a concentration of 0.1 mol / L 1,2-dichloroethane.

[0029] Step 4: Place the electrode sheet prepared in Step 2 into the electrolytic cell assembled in Step 3 for electrolysis. Perform the electrolysis reaction at room temperature using a potentiostatic method with an electrochemical workstation (V = -1.25 V). Vs . RHE) analysis and testing. Nitrogen gas was introduced at a rate of 1 mL / min during electrolysis. -1 The gas is introduced into the single-chamber electrolytic cell at a high speed through the inlet, and high-purity nitrogen is used as the carrier gas to carry the gases generated during electrolysis out of the electrolytic cell through the outlet. Gas chromatography is used to analyze the reaction gases at the outlet. Specifically, a Shimadzu GC-2010 Pro gas chromatograph equipped with a (ShimCap-PLOT Al2O3) capillary column and a flame ionization detector (FID) is used for detection. The products are separated by a capillary column with high-purity nitrogen as the carrier gas at 80 °C, a pressure of 61.5 kPa, and a flow rate of 1.5 mL / min, with a split ratio of 1.7, a detector temperature of 200 °C, a termination time of 16 min, and nitrogen as the make-up gas at a flow rate of 30 mL / min. The organic products show a selectivity of 99.07% for vinyl chloride, 0.70% for ethylene, and 0.22% for acetylene.

[0030] Example 3

[0031] Step 1: Dissolve 3.18 g Na2CO3 in 50 mL of deionized water to obtain a Na2CO3 solution. Weigh 8.08 g Fe(NO3)3·9H2O and dissolve it in 50 mL of deionized water. While stirring, add the Na2CO3 solution dropwise to the Fe(NO3)3 solution until complete precipitation. After complete precipitation, age for 6 h. Filter the precipitate using a vacuum filter. Wash it first with deionized water and then with anhydrous ethanol. Place the filter cake in a vacuum drying oven and dry it at 80 ℃ for 12 h to obtain a dried iron-based precursor precipitate. Place the precursor in a muffle furnace and heat it to 600 ℃ at 5 ℃ / min and hold for 3 h. After natural cooling, grind it to obtain Fe2O3 powder.

[0032] Step 2: Preparation of the working electrode: Weigh 2 mg of Fe2O3 powder and disperse it in a mixed solution of 60 μL each of n-propanol, ethylene glycol, and deionized water. Add 20 μL of DuPont 5% Nafion D520 solution, and then ultrasonically disperse to obtain a catalyst slurry. Dry the carbon paper after washing with deionized water under an infrared lamp (100 W). Then, coat 100 μL of the uniformly dispersed catalyst slurry onto the dried 1 cm layer. 2 The working electrode is obtained by re-drying the carbon cloth, wherein the catalyst loading is 1 mg / cm³. 2 .

[0033] Step 3: The prepared working electrode, silver / silver chloride electrode, Pt electrode, and a closed single-chamber electrolytic cell with an inlet and an outlet (located on opposite sides of the working electrode) are combined to form a three-electrode system. Using an N,N-dimethylformamide solution containing 0.1 mol / L tetrabutylammonium hydroxide as the solvent, an appropriate amount of 1,2-dichloroethane solute is added to prepare an electrolyte with a concentration of 0.1 mol / L 1,2-dichloroethane.

[0034] Step 4: Place the electrode sheet prepared in Step 2 into the electrolytic cell assembled in Step 3 for electrolysis. Perform the electrolysis reaction at room temperature using a potentiostatic method with an electrochemical workstation (V = -1.25 V). Vs . RHE) analysis and testing. Nitrogen gas was introduced at a rate of 1 mL / min during electrolysis. -1The gas is introduced into the single-chamber electrolytic cell at a high speed through the inlet, and high-purity nitrogen is used as the carrier gas to carry the gases generated during electrolysis out of the electrolytic cell through the outlet. Gas chromatography is used to analyze the reaction gases at the outlet. Specifically, a Shimadzu GC-2010 Pro gas chromatograph equipped with a (ShimCap-PLOT Al2O3) capillary column and a flame ionization detector (FID) is used for detection. The products are separated by a capillary column with high-purity nitrogen as the carrier gas at 80 °C, a pressure of 61.5 kPa, and a flow rate of 1.5 mL / min, with a split ratio of 1.7, a detector temperature of 200 °C, a termination time of 16 min, and nitrogen as the make-up gas at a flow rate of 30 mL / min. The organic products show a selectivity of 97.79% for vinyl chloride, 2.20% for ethylene, and 0.02% for acetylene.

[0035] Example 4

[0036] Step 1: Dissolve 3.18 g Na2CO3 in 50 mL of deionized water to obtain a Na2CO3 solution. Weigh 5.02 g Mn(NO3)2·4H2O and dissolve it in 50 mL of deionized water. While stirring, add the Na2CO3 solution dropwise to the Mn(NO3)2 solution until complete precipitation. After complete precipitation, age for 6 h. Filter the precipitate using a vacuum filtration device. Wash it first with deionized water and then with anhydrous ethanol. Place the filter cake in a vacuum drying oven and dry it at 80 ℃ for 12 h to obtain a dried manganese-based precursor precipitate. Place the precursor in a muffle furnace and heat it to 600 ℃ at 5 ℃ / min and hold for 3 h. After natural cooling, grind it to obtain MnO powder.

[0037] Step 2: Preparation of the working electrode: Weigh 2 mg of MnO powder and disperse it in a mixed solution of 60 μL each of n-propanol, ethylene glycol, and deionized water. Add 20 μL of DuPont 5% Nafion D520 solution, and then ultrasonically disperse to obtain a catalyst slurry. Dry the carbon paper after washing with deionized water under an infrared lamp (100 W). Then, coat 100 μL of the uniformly dispersed catalyst slurry onto the dried 1 cm layer. 2 The working electrode is obtained by re-drying the carbon cloth, wherein the catalyst loading is 1 mg / cm³. 2 .

[0038] Step 3: The prepared working electrode, silver / silver chloride electrode, Pt electrode, and a closed single-chamber electrolytic cell with an inlet and an outlet (located on opposite sides of the working electrode) are combined to form a three-electrode system. Using an N,N-dimethylformamide solution containing 0.1 mol / L tetrabutylammonium hydroxide as the solvent, an appropriate amount of 1,2-dichloroethane solute is added to prepare an electrolyte with a concentration of 0.1 mol / L 1,2-dichloroethane.

[0039] Step 4: Place the electrode sheet prepared in Step 2 into the electrolytic cell assembled in Step 3 for electrolysis. Perform the electrolysis reaction at room temperature using a potentiostatic method with an electrochemical workstation (V = -1.25 V). Vs . RHE) analysis and testing. Nitrogen gas was introduced at a rate of 1 mL / min during electrolysis. -1 The gas is introduced into the single-chamber electrolytic cell at a high speed through the inlet, and high-purity nitrogen is used as the carrier gas to carry the gases generated during electrolysis out of the electrolytic cell through the outlet. Gas chromatography is used to analyze the reaction gases at the outlet. Specifically, a Shimadzu GC-2010 Pro gas chromatograph equipped with a (ShimCap-PLOT Al2O3) capillary column and a flame ionization detector (FID) is used for detection. The products are separated by a capillary column with high-purity nitrogen as the carrier gas at 80 °C, a pressure of 61.5 kPa, and a flow rate of 1.5 mL / min, with a split ratio of 1.7, a detector temperature of 200 °C, a termination time of 16 min, and nitrogen as the make-up gas at a flow rate of 30 mL / min. The organic products show a selectivity of 99.32% for vinyl chloride, 0.20% for ethylene, and 0.49% for acetylene.

[0040] Example 5

[0041] Step 1: Dissolve 3.18 g Na2CO3 in 50 mL of deionized water to obtain a Na2CO3 solution. Weigh 5.82 g Cu(NO3)2·3H2O and dissolve it in 50 mL of deionized water. While stirring, add the Na2CO3 solution dropwise to the Cu(NO3)2 solution until complete precipitation. After complete precipitation, age for 6 h. Filter the precipitate using a vacuum filter. Wash the precipitate first with deionized water and then with anhydrous ethanol. Place the filter cake in a vacuum drying oven and dry at 80 ℃ for 12 h to obtain a dried copper-based precursor precipitate. Place the precursor in a muffle furnace and heat it to 600 ℃ at 5 ℃ / min and hold for 3 h. After natural cooling, grind to obtain CuO powder.

[0042] Step 2: Preparation of the working electrode: Weigh 2 mg of CuO powder and disperse it in a mixed solution of 60 μL each of n-propanol, ethylene glycol, and deionized water. Add 20 μL of DuPont 5% Nafion D520 solution, and then ultrasonically disperse to obtain a catalyst slurry. Dry the carbon paper after washing with deionized water under an infrared lamp (100 W). Then, coat the dried carbon paper with 100 μL of the uniformly dispersed catalyst slurry onto a 1 cm thick sheet. 2 The working electrode is obtained by re-drying the carbon cloth, wherein the catalyst loading is 1 mg / cm³. 2 .

[0043] Step 3: The prepared working electrode, silver / silver chloride electrode, Pt electrode, and a closed single-chamber electrolytic cell with an inlet and an outlet (located on opposite sides of the working electrode) are combined to form a three-electrode system. Using an N,N-dimethylformamide solution containing 0.1 mol / L tetrabutylammonium hydroxide as the solvent, an appropriate amount of 1,2-dichloroethane solute is added to prepare an electrolyte with a concentration of 0.1 mol / L 1,2-dichloroethane.

[0044] Step 4: Place the electrode sheet prepared in Step 2 into the electrolytic cell assembled in Step 3 for electrolysis. Perform the electrolysis reaction at room temperature using a potentiostatic method with an electrochemical workstation (V = -1.25 V). Vs . RHE) analysis and testing. Nitrogen gas was introduced at a rate of 1 mL / min during electrolysis. -1 The gas is introduced into the single-chamber electrolytic cell at a high speed through the inlet, and high-purity nitrogen is used as the carrier gas to carry the gases generated during electrolysis out of the electrolytic cell through the outlet. Gas chromatography is used to analyze the reaction gases at the outlet. Specifically, a Shimadzu GC-2010 Pro gas chromatograph equipped with a (ShimCap-PLOT Al2O3) capillary column and a flame ionization detector (FID) is used for detection. The products are separated by a capillary column with high-purity nitrogen as the carrier gas at 80 °C, a pressure of 61.5 kPa, and a flow rate of 1.5 mL / min, with a split ratio of 1.7, a detector temperature of 200 °C, a termination time of 16 min, and nitrogen as the make-up gas at a flow rate of 30 mL / min. The organic products show a selectivity of 90.63% for vinyl chloride, 4.65% for ethylene, and 4.71% for acetylene.

[0045] The specific evaluation results are shown in Table 1.

[0046] Table 1

[0047] As shown above, the electrochemical performance was tested using a three-electrode constant voltage method with 1,2-dichloroethane as the reactant. Experiments revealed that within a certain voltage operating range, various catalysts could be used for electrocatalytic dechlorination to produce vinyl chloride, with a selectivity of over 99% for vinyl chloride from carbon-containing organic compounds. Compared to traditional DCE cracking, this method achieves the dechlorination of hydrogen chloride to vinyl chloride under mild conditions, aligning with green and sustainable development requirements and providing a highly selective electrocatalytic method for the dechlorination of hydrogen chloride from DCE to produce vinyl chloride.

[0048] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method of electrocatalytically preparing vinyl chloride from 1,2-dichloroethane, characterized in that: The working electrode of the method uses a metal oxide as a catalyst, and the metal oxide is selected from at least one of the oxides of Pd, Mn, Fe, Co, Ni, Cu, Ru, and Mo.

2. The method of claim 1, wherein: The metal oxide is selected from one or more of Co2O3, NiO, Fe2O3, MnO, and CuO.

3. The method of claim 1, wherein: The metal oxide is prepared by a precipitation method, and the preparation is performed by mixing a metal salt solution with a precipitant solution, precipitating the metal by forming an insoluble compound through a reaction between the metal ions and the precipitant, separating, washing, and drying the precipitate, and calcining the precipitate at a high temperature of 300-700°C in an air atmosphere to obtain a metal oxide powder.

4. The method of any one of claims 1-3, wherein: The working electrode comprises an electrode material and a catalyst uniformly dispersed on the electrode material, and the electrode material is at least one of carbon paper, carbon cloth, foamed nickel, and foamed copper.

5. The method of claim 4, wherein: The electrode material is also uniformly dispersed with Nafion.

6. The method of claim 4, wherein: The catalyst loading on the working electrode is 0.2-5 mg / cm 2 .

7. The method of claim 4, wherein: The working electrode is prepared by preparing a catalyst slurry, adding a Nafion solution to the catalyst slurry, and uniformly coating the catalyst slurry on the electrode material, and drying to obtain the working electrode.

8. The method of any one of claims 1-3, wherein: The method is performed in a single-chamber reaction cell, an H-shaped electrolytic cell, or a continuous electrolytic cell, and the counter electrode is selected from foamed nickel, foamed copper, a Pt electrode, or a graphite electrode. The electrolyte is a solution containing 1,2-dichloroethane and a supporting electrolyte, and the solvent of the electrolyte is selected from one of water, ethanol, dimethyl sulfoxide, and N,N-dimethylformamide. The supporting electrolyte is selected from one of sodium sulfate, potassium bicarbonate, potassium sulfate, and tetrabutylammonium hydroxide.

9. The method of claim 8, wherein: In the electrolyte, the supporting electrolyte is tetrabutylammonium hydroxide, the concentration of tetrabutylammonium hydroxide is 0.1-2 mol / L, and the concentration of 1,2-dichloroethane is 0.1-4 mol / L.

10. The method of claim 8, wherein: The electrochemical reaction is performed at room temperature under a constant current or a constant potential, the electrochemical cathode potential is -5-0 V (relative to a saturated calomel electrode), and the constant current is 1-200 mA.

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