Preparation method of catalytic cracking reaction composite metal catalyst and application of catalytic cracking reaction composite metal catalyst in preparation of vinylidene chloride

Abstract

The invention belongs to the technical field of catalysts, and particularly relates to a preparation method of a catalytic cracking reaction composite metal catalyst and application of the catalytic cracking reaction composite metal catalyst in preparation of vinylidene chloride, and the preparation method of the catalytic cracking reaction composite metal catalyst comprises the following steps: (1) mixing a chitosan solution and an acetic acid solution, adjusting the pH value to obtain a mixed solution, adding the zinc lactate solution into the mixed solution, and uniformly mixing to obtain a zinc chelate solution; (2) mixing the zinc chelate solution, an aluminum-containing compound, a silicon-containing compound and a template agent to form slurry, performing spray granulation to form molecular sieve particles, and performing crystallization, washing and drying to obtain zinc-containing molecular sieve microspheres; (3) mixing cesium sulfate, oleic acid and octadecene for reaction to obtain a cesium oleate solution; and (4) dispersing the zinc-containing molecular sieve microspheres into a cesium oleate solution for reaction to obtain the composite metal catalyst for catalytic cracking reaction. According to the preparation process, the process conditions are optimized, and a perfect catalytic system is formed.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of catalysts, and particularly relates to a preparation method of a catalytic cracking reaction composite metal catalyst and application thereof in preparation of vinylidene chloride. BACKGROUND

[0002] Vinylidene chloride is a colorless oily liquid, and its molecular formula is C2H2Cl2. Vinylidene chloride has a pungent odor, a melting point of -122℃, a boiling point of 31.2℃, is insoluble in water, and soluble in many organic solvents such as ethanol and diethyl ether. Vinylidene chloride has two symmetrical chlorine atoms on one carbon, which makes vinylidene chloride have relatively active chemical properties. Vinylidene chloride is an important monomer in the polymer synthesis industry, and is commonly used to produce latex and resin products.

[0003] Polyvinylidene chloride is a copolymer formed by polymerization of vinylidene chloride, and is currently widely used in food, medicine, tobacco, paint and other fields. Polyvinylidene chloride resin is mainly used in three aspects: first, polyvinylidene chloride resin for fibers, mainly used in seat cushions, artificial turf, fishing nets, flame-retardant cloth and the like; second, polyvinylidene chloride resin for solution type coating, mainly used in paint, adhesive and viscous agent; and third, polyvinylidene chloride resin multilayer co-extruded film, mainly used in packaging of food and beverages. Polyvinylidene chloride latex is a copolymer produced by copolymerization of vinylidene chloride and acrylate monomers, and is mainly used in packaging of pharmaceuticals, beverages, tobacco and the like.

[0004] For preparation of vinylidene chloride, the main methods currently include 1,1,2-trichloroethane alkaline hydrolysis method, 1,2-dichloroethane chlorination method, chloroethylene hydrogen chlorination method, chloroethylene chlorination method, ethane chlorination method and the like. Because the blocking performance of polyvinylidene chloride is far superior to other similar products, polyvinylidene chloride has a wide range of applications, and therefore the potential market demand for vinylidene chloride is large. Therefore, a synthesis process route with less by-products, simple process, environmental friendliness, mild reaction conditions and green atom economy is the key to production of vinylidene chloride. Among them, the method of producing vinylidene chloride by using 1,1,2-trichloroethane gas phase catalytic dehydrochlorination does not require additional investment of alkali, and does not produce high-salt wastewater, and therefore this method is worth further research.

[0005] 1,1,2-trichloroethane is a colorless transparent and non-flammable liquid with characteristics similar to chloroform, has a melting point of -35℃, a boiling point of 113-114℃, is insoluble in water, and is miscible with many organic solvents. 1,1,2-trichloroethane can be prepared by catalytic chlorination of ethane or ethylene, and can be prepared by further chlorination of 1,2-dichloroethane in industry.

[0006] The traditional 1,1,2-trichloroethane base hydrolysis method for preparing vinylidene chloride mainly adopts alkali solution and 1,1,2-trichloroethane to react at normal pressure to remove one molecule of hydrogen chloride to generate vinylidene chloride and the corresponding salt solution, and the method for preparing vinylidene chloride has serious environmental pollution; the 1,2-dichloroethane chlorination method generates 1,1,2-trichloroethane by chlorination reaction of 1,2-dichloroethane and chlorine, and then the 1,1,2-trichloroethane is refined and subjected to base hydrolysis saponification to obtain vinylidene chloride, and the method has harsh reaction conditions and more by-products; the chloroethylene hydrochlorination method adopts thermal cracking to remove hydrogen chloride, and the process flow is long, and more equipment is required, so the economic investment is large; the chloroethylene chlorination method catalytically generates 1,1,2-trichloroethane by passing chloroethylene and chlorine into a reactor, and then the 1,1,2-trichloroethane is subjected to further saponification reaction to generate vinylidene chloride. The ethane chlorination method uses ethane as a raw material, and high-temperature chlorination generates a mixture containing hydrogen chloride, chloroethane, chloroethylene and vinylidene chloride, and then the products are separated by rectification, and the method has a long process flow, large energy consumption and high investment cost. The 1,1,2-trichloroethane gas phase catalytic dehydrochlorination method does not generate waste water at all, and meets the green environmental protection concept.

[0007] Chinese patent CN112774591A discloses a continuous preparation system and method of vinylidene chloride, which couples two-stage high gravity reactors, and uses steam stripping to remove the product vinylidene chloride and water vapor from the reaction system in the form of azeotrope. The method has more by-products, low conversion rate, and large waste water pollution, and the subsequent environmental protection treatment cost is high.

[0008] At present, the 1,1,2-trichloroethane base hydrolysis method for preparing vinylidene chloride still has many problems, such as many side reactions, rectification purification and large energy consumption; and the base hydrolysis method inevitably needs to invest a large amount of alkali solution, and generates salt-containing waste water in the generation process, which pollutes the environment and has high subsequent treatment cost.

[0009] The existing vinylidene chloride preparation technology has a series of key bottleneck problems such as long process flow, unfriendly production process environment, many by-products and high energy consumption, and therefore it is urgent to develop an environment-friendly high-efficiency catalyst for preparing vinylidene chloride. SUMMARY

[0010] According to the deficiencies in the prior art, the technical problem to be solved by the present application is to provide a preparation method of a catalytic cracking reaction composite metal catalyst, so as to obtain a composite metal catalyst with better catalytic performance; and the present application also provides an application of the catalytic cracking reaction composite metal catalyst in preparing vinylidene chloride.

[0011] The technical scheme adopted by the present application to solve the technical problem is: The preparation method of the catalytic cracking reaction composite metal catalyst comprises the following steps: (1) mixing chitosan solution with acetic acid solution, adjusting pH to obtain a mixed solution, then adding zinc lactate solution into the mixed solution and mixing to obtain a zinc chelate solution; (2) mixing the zinc chelate solution, an aluminum-containing compound, a silicon-containing compound and a template agent to form a slurry, spray granulating to form molecular sieve particles, then placing into an alkaline solution for crystallization, washing, drying to obtain zinc-containing molecular sieve microspheres; (3) mixing cesium sulfate, oleic acid and octadecene under nitrogen protection to obtain a cesium oleate solution; (4) dispersing the zinc-containing molecular sieve microspheres into the cesium oleate solution under nitrogen protection for reaction, filtering, washing, shaping, drying and calcining to obtain a catalytic cracking reaction composite metal catalyst.

[0012] In the formula, R represents a C1-C20 alkyl group or a C6-C20 aryl group; n represents an integer of 1-10; and m represents an integer of 1-10. In the step (1), the concentration of the acetic acid solution is 10-14 wt%, the concentration of the chitosan solution is 0.5-2 wt%, the mass ratio of acetic acid in the acetic acid solution to chitosan in the chitosan solution is 1:0.05-0.15, and the pH is adjusted by using a sodium hydroxide solution, the concentration of the sodium hydroxide solution is 0.1-0.5 M, and the pH value is 6-7.

[0013] In the step (1), the mass ratio of zinc lactate in the zinc lactate solution to chitosan in the chitosan solution is 1:0.05-0.11, the concentration of the zinc lactate solution is 0.1-2 M, the mixing temperature is room temperature, and the mixing time is 2-6 h.

[0014] In the step (2), the aluminum-containing compound is aluminum isopropoxide, the silicon-containing compound is tetraethyl orthosilicate, the template agent is tetrapropylammonium bromide, the mass ratio of the zinc chelate solution, the aluminum-containing compound, the silicon-containing compound and the template agent is 0.01-0.5:1:40-60:0.5-1.5, and the mixing time is 0.5-3 h.

[0015] In the step (2), the average particle size of the molecular sieve particles is 25-50 μm, the alkaline solution is a tetrapropylammonium hydroxide solution, the concentration of the alkaline solution is 2-3 wt%, the ratio of the alkaline solution to the molecular sieve particles is 1-20:1, the alkaline solution is measured in ml, and the molecular sieve particles are measured in g; the crystallization temperature is 150-190 ℃, the crystallization time is 24-72 h, and the drying temperature is 80-150 ℃.

[0016] In the step (3), the mass ratio of cesium sulfate, oleic acid and octadecene is 1:25-100:0.25-0.5; the mixing reaction temperature is 80-150 ℃, and the mixing reaction time is 1.5-2.5 h.

[0017] The ratio of the zinc-containing molecular sieve microspheres to the cesium oleate solution in step (4) is 1:1-10, the zinc-containing molecular sieve microspheres are measured in grams, and the cesium oleate solution is measured in milliliters; the reaction temperature is 25-30 DEG C, the reaction time is 0.5-6 hours, the calcination temperature is 450-650 DEG C, and the calcination time is 4-6 hours.

[0018] The application of the catalytic cracking reaction composite metal catalyst prepared by the preparation method in the preparation of vinylidene chloride is as follows: 1,1,2-trichloroethane is mixed with nitrogen to obtain a mixed gas, the catalytic cracking reaction composite metal catalyst is added into the mixed gas to perform a cracking reaction, and vinylidene chloride product is obtained after condensation.

[0019] The mass ratio of the 1,1,2-trichloroethane to nitrogen is 1:100-1000, and the volume space velocity of the mixed gas is 25-30 min -1 .

[0020] The cracking reaction temperature is 140-160 DEG C, and the cracking reaction pressure is 0.3-2 MPa.

[0021] The application has the following beneficial effects: The application has the following beneficial effects:

[0022] The application introduces oleate ions by converting cesium sulfate into cesium oleate and then loading the cesium oleate on the zinc-containing molecular sieve microspheres; the oleate is dispersed on the surface of the pore channel of the zinc-containing molecular sieve microspheres through adsorption, and then the cesium oleate and the chelate of chitosan-zinc lactate on the molecular sieve are further dispersed through intermolecular forces, the action mode of the two is relatively mild, and the phenomenon of excessive loading of active components in the traditional loading mode can be effectively avoided. At the same time, the special molecular structure of the cesium oleate enables it to exhibit good dispersibility in the gap of the zinc-containing molecular sieve microspheres, which can significantly reduce the problem of waste of active sites caused by aggregation, thereby greatly improving the effective utilization rate of the active sites of the molecular sieve. In the zinc-containing molecular sieve microspheres, the cesium ions in the cesium oleate can synergize with the previously introduced zinc ions, and the zinc ions can regulate the active center structure and electron cloud distribution of the cesium ions in the catalyst, thereby improving the activity of the composite metal catalyst, improving the conversion efficiency of the raw materials in the reaction process of synthesizing vinylidene chloride, optimizing the selectivity of the reaction, and shortening the reaction time, so that the catalyst exhibits more excellent catalytic performance in the synthesis of vinylidene chloride. The preparation process of the application optimizes the process conditions, improves the product quality, and forms a perfect catalytic system. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is the SEM image of the catalytic cracking reaction composite metal catalyst prepared in Example 1 of the application. DETAILED DESCRIPTION

[0024] The application will be further described below in combination with examples.

[0025] Example 1 The preparation method of the catalytic cracking reaction composite metal catalyst comprises the following steps: (1) 500g of a 1wt% chitosan solution and 500g of a 12wt% acetic acid solution are mixed at room temperature for 3h, and after being fully dissolved, a 0.2M sodium hydroxide solution is used to adjust the pH to 6.5 to obtain a mixed solution, and then 400mL of a 0.5M zinc lactate solution is added to the mixed solution and fully mixed at room temperature for 5h to obtain a zinc chelate solution; (2) 10g of the zinc chelate solution, 100g of aluminum isopropoxide, 5000g of tetraethyl orthosilicate and 100g of tetrapropylammonium bromide are mixed for 1h to form a slurry, and the slurry is formed into molecular sieve particles with an average particle size of 30μm through spray granulation, and then 1000g of the molecular sieve particles are placed into a 2.5wt% 10000ml tetrapropylammonium hydroxide solution for crystallization at 150℃ for 48h, and then washed to neutral, and dried at 80℃ to obtain zinc-containing molecular sieve microspheres; (3) 10g of cesium sulfate, 500g of oleic acid and 5g of octadecene are mixed at 150℃ for 1.5h under nitrogen protection to obtain a cesium oleate solution; (4) Under the protection of nitrogen, 500g of the zinc-containing molecular sieve microspheres was dispersed into 2500ml of the cesium oleate solution to react at 30℃ for 2h, and then filtered and washed, kneaded and shaped, and dried, and then calcined at 500℃ for 5h to obtain the catalytic cracking reaction composite metal catalyst, an SEM image of which is shown in Figure 1 .

[0026] Application of the catalytic cracking reaction composite metal catalyst in the preparation of vinylidene chloride: 200g of the catalytic cracking reaction composite metal catalyst was put into a DN25 fixed bed reactor, with an effective loading height of 0.3m, and 10cm high quartz sand was laid on the upper and lower parts of the bed; nitrogen was replaced for 30min, and then a mixture of 1,1,2-trichloroethane and nitrogen with a mass ratio of 1:1000 was continuously introduced, and the reaction was carried out at 150℃ and a space velocity of 25min -1 -1. The pressure in the fixed bed reactor was 2MPa, and after the reaction, the gas was condensed to obtain a vinylidene chloride liquid; the conversion rate of 1,1,2-trichloroethane was 38.28%, and the selectivity of vinylidene chloride was 88.23%.

[0027] Example 2 The preparation method of the catalytic cracking reaction composite metal catalyst comprises the following steps: (1) 500g of a 2wt% chitosan solution and 500g of a 15wt% acetic acid solution were mixed at room temperature for 5h, and after being fully dissolved, 0.1M sodium hydroxide solution was used to adjust the pH to 7, to obtain a mixed solution, and then 400ml of a 2M zinc lactate solution was added to the mixed solution and fully mixed at room temperature for 6h, to obtain a zinc chelate solution.

[0028] (2) 50g of the zinc chelate solution, 100g of aluminum isopropoxide, 6000g of tetraethyl orthosilicate, and 150g of tetrapropylammonium bromide were mixed for 3h to form a slurry, which was spray granulated to form molecular sieve particles with an average particle size of 25μm, and then 1000g of the molecular sieve particles were put into a 3wt%, 20000ml tetrapropylammonium hydroxide solution to crystallize at 170℃ for 72h, and washed until neutral, and then dried at 150℃ to obtain zinc-containing molecular sieve microspheres; (3) Under the protection of nitrogen, 10g of cesium sulfate, 250g of oleic acid, and 3.5g of octadecene were mixed at 80℃ for 2h to obtain a cesium oleate solution; (4) Under the protection of nitrogen, 500g of the zinc-containing molecular sieve microspheres was dispersed into 5000ml of the cesium oleate solution to react at 28℃ for 6h, and then filtered and washed, kneaded and shaped, and dried, and then calcined at 650℃ for 4h to obtain the catalytic cracking reaction composite metal catalyst.

[0029] Application of the catalytic cracking reaction composite metal catalyst in the preparation of vinylidene chloride: Take 200g catalytic cracking reaction composite metal catalyst into DN25 fixed bed reactor, effective loading height 0.4 meters, bed layer each paving 10cm height quartz sand; with nitrogen replacement 50min, then continuously into mass ratio 1:500 1,1,2-trichloroethane and nitrogen mixed gas, under the condition of 140℃, space velocity 30min -1 Reaction, the pressure in the fixed bed reactor is 0.3MPa, after reaction gas is condensed to get liquid vinylidene chloride; 1,1,2-trichloroethane conversion rate is 37.62%, the selectivity of vinylidene chloride is 87.02%.

[0030] Example 3 The preparation method of the catalytic cracking reaction composite metal catalyst comprises the following steps: (1) mix 500g, 0.5wt% chitosan solution with 500g, 10wt% acetic acid solution at room temperature for 2h, after fully dissolving, use 0.5M sodium hydroxide solution to adjust pH to 6, get mixed solution, then take 1100mL, 0.1M zinc lactate solution into the mixed solution, mix at room temperature for 2h, get zinc chelate solution.

[0031] (2) mix 1g zinc chelate solution, 100g aluminum isopropoxide, 4000g tetraethyl orthosilicate with 50g tetrapropylammonium bromide for 0.5h, form slurry, form molecular sieve particles with average particle size of 50μm by spray granulation, then put 1000g molecular sieve particles into 2wt%, 1000ml tetrapropylammonium hydroxide solution, carry out crystallization at 190℃ for 24h, wash to neutral, after drying at 120℃, get zinc-containing molecular sieve microspheres; (3) under nitrogen protection, mix 10g cesium sulfate, 1000g oleic acid with 2.5g octadecene at 120℃ for 2.5h to get cesium oleate solution; (4) under nitrogen protection, disperse 500g zinc-containing molecular sieve microspheres into 500ml cesium oleate solution at 25℃ for 0.5h, then filter and wash, knead into shape, dry, calcine at 450℃ for 6h to get catalytic cracking reaction composite metal catalyst.

[0032] Application of the catalytic cracking reaction composite metal catalyst in preparing vinylidene chloride: Take 200g catalytic cracking reaction composite metal catalyst into DN25 fixed bed reactor, effective loading height 0.4 meters, bed layer each paving 10cm height quartz sand; with nitrogen replacement 20min, then continuously into mass ratio 1:100 1,1,2-trichloroethane and nitrogen mixed gas, at 160℃, space velocity 27min -1The reaction was carried out under the conditions, the pressure in the fixed bed reactor was 1 MPa, and the gas after reaction was condensed to obtain liquid vinylidene chloride; the conversion of 1,1,2-trichloroethane was 40.71%, and the selectivity of vinylidene chloride was 82.86%.

[0033] Comparative Example 1 In the preparation process of the catalytic cracking reaction composite metal catalyst, no chitosan solution was added in step (1), and the remaining steps were the same as in Example 1. The conversion of 1,1,2-trichloroethane was 22.61%, and the selectivity of vinylidene chloride was 58.08%.

[0034] Comparative Example 2 In the preparation process of the catalytic cracking reaction composite metal catalyst, no acetic acid solution was added in step (1), and the remaining steps were the same as in Example 1. The conversion of 1,1,2-trichloroethane was 27.53%, and the selectivity of vinylidene chloride was 63.82%.

[0035] Comparative Example 3 The preparation process of the catalytic cracking reaction composite metal catalyst was omitted in steps (3) and (4), and the zinc-containing molecular sieve microspheres were directly used as the catalyst, and the remaining steps were the same as in Example 1. The conversion of 1,1,2-trichloroethane was 20.75%, and the selectivity of vinylidene chloride was 47.98%.

[0036] Comparative Example 4 The preparation process of the catalytic cracking reaction composite metal catalyst was omitted in step (3), and the zinc-containing molecular sieve microspheres were added into the cesium sulfate solution in step (4), and the remaining steps were the same as in Example 1. The conversion of 1,1,2-trichloroethane was 21.24%, and the selectivity of vinylidene chloride was 55.39%.

[0037] As can be known from the above, the composite metal catalyst has excellent catalytic performance, as can be known from the comparison between Comparative Example 1, Comparative Example 2 and Example 1, chitosan cannot form a zinc chelate without being added, the catalyst prepared cannot form a steric hindrance effect due to the lack of a special space structure, and the catalytic performance of the catalyst is greatly reduced, and without the addition of acetic acid, chitosan is difficult to be dispersed and dissolved in water due to strong intermolecular hydrogen bond action, and in the subsequent reaction with zinc ions, sufficient contact and coordination reaction cannot occur, so that the formation process of the chelate is hindered; as can be known from the comparison between Comparative Example 3 and Example 1, only using a zinc-containing catalyst cannot achieve high 1,1,2-trichloroethane conversion and vinylidene chloride selectivity; as can be known from the comparison between Comparative Example 4 and Example 1, loading with sulfate is not as mild as loading with oleate, and overloading occurs, which affects the catalytic activity, the interaction between the oleate and the surface of the molecular sieve in the application can effectively avoid the overloading of the active component in the traditional loading mode; and the special molecular structure of cesium oleate makes it exhibit good dispersity in the gap of the zinc-containing molecular sieve microspheres.

Claims

1. A method for preparing a catalytic cracking reaction composite metal catalyst, characterized by, The method comprises the following steps: (1) mixing a chitosan solution with an acetic acid solution, adjusting pH to obtain a mixed solution, and then adding a zinc lactate solution into the mixed solution and mixing to obtain a zinc chelate solution; (2) mixing the zinc chelate solution, an aluminum-containing compound, a silicon-containing compound and a template agent to form a slurry, spray granulating to form molecular sieve particles, and then placing the molecular sieve particles into an alkaline solution for crystallization, washing, drying to obtain zinc-containing molecular sieve microspheres; (3) mixing cesium sulfate, oleic acid and octadecene under nitrogen protection to obtain a cesium oleate solution; (4) dispersing the zinc-containing molecular sieve microspheres into the cesium oleate solution under nitrogen protection for reaction, filtering, washing, shaping, drying and calcining to obtain a catalytic cracking reaction composite metal catalyst.

2. The method for preparing the composite metal catalyst for catalytic cracking reaction according to claim 1, characterized in that, In step (1), the concentration of the acetic acid solution is 10-14 wt%, the concentration of the chitosan solution is 0.5-2 wt%, the mass ratio of acetic acid in the acetic acid solution to chitosan in the chitosan solution is 1:0.05-0.15, and the pH is adjusted by using a sodium hydroxide solution, the concentration of the sodium hydroxide solution is 0.1-0.5 M, and the pH value is 6-7.

3. The method for preparing the composite metal catalyst for catalytic cracking reaction according to claim 1, characterized in that, In step (1), the mass ratio of zinc lactate in the zinc lactate solution to chitosan in the chitosan solution is 1:0.05-0.11, the concentration of the zinc lactate solution is 0.1-2 M, the mixing temperature is room temperature, and the mixing time is 2-6 h.

4. The method for preparing the composite metal catalyst for catalytic cracking reaction according to claim 1, characterized in that, In step (2), the aluminum-containing compound is aluminum isopropoxide, the silicon-containing compound is tetraethyl orthosilicate, the template agent is tetrapropylammonium bromide, the mass ratio of the zinc chelate solution, the aluminum-containing compound, the silicon-containing compound and the template agent is 0.01-0.5:1:40-60:0.5-1.5, and the mixing time is 0.5-3 h.

5. The method for preparing the composite metal catalyst for catalytic cracking reaction according to claim 1, characterized in that, In step (2), the average particle size of the molecular sieve particles is 25-50 μm, the alkaline solution is a tetrapropylammonium hydroxide solution, the concentration of the alkaline solution is 2-3 wt%, the ratio of the alkaline solution to the molecular sieve particles is 1-20:1 (the alkaline solution is measured in ml and the molecular sieve particles are measured in g), the crystallization temperature is 150-190 ℃, the crystallization time is 24-72 h, and the drying temperature is 80-150 ℃.

6. The method for preparing the composite metal catalyst for catalytic cracking reaction according to claim 1, characterized in that, In step (3), the mass ratio of cesium sulfate, oleic acid and octadecene is 1:25-100:0.25-0.5, the mixing reaction temperature is 80-150 ℃, and the mixing reaction time is 1.5-2.5 h.

7. The method for preparing the composite metal catalyst for catalytic cracking reaction according to claim 1, characterized in that, In step (4), the ratio of the zinc-containing molecular sieve microspheres to the cesium oleate solution is 1:1-10 (the zinc-containing molecular sieve microspheres are measured in g and the cesium oleate solution is measured in ml), the reaction temperature is 25-30 ℃, the reaction time is 0.5-6 h, the calcination temperature is 450-650 ℃, and the calcination time is 4-6 h.

8. Use of the composite metal catalyst obtained by the production process according to any one of claims 1 to 7 for the production of vinylidene chloride, characterized in that, The catalytic cracking reaction composite metal catalyst is added into mixed gas obtained by mixing 1,1,2-trichloroethane with nitrogen to perform a cracking reaction, and a product of vinylidene chloride is obtained by condensation after the reaction.

9. Use of the composite metal catalyst according to claim 8 for the production of vinylidene chloride, characterized in that, 1,1,2-trichloroethane to nitrogen in a mass ratio of 1:100-1000, the volume space velocity of the mixed gas is 25-30 min -1 .

10. Use of the composite metal catalyst according to claim 8 for the production of vinylidene chloride, characterized in that, The cracking reaction temperature is 140-160 ℃, and the cracking reaction pressure is 0.3-2 MPa.

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