Method for simultaneously preparing vinylidene fluoride and vinyl fluoride

Abstract

The invention discloses a method for simultaneously preparing vinylidene fluoride and vinyl fluoride, which comprises the following step of: reacting difluoroethane under the action of a catalyst and oxidizing gas to prepare the vinylidene fluoride and the vinyl fluoride, the catalyst comprises an active component and a carrier compound, the active component comprises an active component A, or the active component comprises an active component A and an active component B; the active component A is selected from at least one of molybdenum salt, lanthanum salt, nickel salt, chromium salt, vanadium salt, platinum salt or palladium salt; the active component B is selected from at least one of sodium salt, potassium salt, cesium salt, magnesium salt or calcium salt. According to the method, difluoroethane is taken as a raw material, and vinylidene fluoride and vinyl fluoride are prepared at the same time under the action of a catalyst and oxidizing gas.

Description

Technical Field

[0001] This invention relates to a method for preparing fluorinated olefins, and particularly to a method for simultaneously preparing vinylidene fluoride and vinyl fluoride. Background Technology

[0002] Vinylidene fluoride (VDF) is the main raw material for polyvinylidene fluoride (PVDF). PVDF is widely used in high-tech fields such as aerospace, high-end coatings, new energy, environmental protection, medical, and scientific research. PVDF has the characteristics of aging resistance and easy processing, combining the chemical stability of high-strength fluoropolymers with the easy processing of general-purpose resins. In lithium batteries, PVDF is used as a positive electrode binder and separator coating. Porous membranes, gels, and separators made of PVDF resin are also used in lithium secondary batteries, and this application has become one of the fastest-growing markets for PVDF demand.

[0003] Currently, there are numerous patents related to the preparation of vinylidene fluoride (VEF). Patent (CN114471653B) discloses that Pt-deposited hollow carbon nitride microsphere catalysts can be used for the catalytic cracking of 1,1,1-difluorochloroethane (HCFC-142b) to prepare VEF, with low reaction temperature and simple operation. Patent (CN111905779A) discloses the preparation of a BaF2-based catalyst via a hydrothermal method, introducing a large amount of alkaline earth, transition metals, and lanthanides as co-catalysts, resulting in different conversion rates of HCFC-142b and VEF selectivity. Patent (CN113649032B) shows that combining the hydrothermal method with a co-precipitation method can significantly increase the specific surface area of ​​alkaline earth metal fluoride catalysts, thereby improving the VEF selectivity. In industrial production, VEF is mainly prepared by high-temperature cracking and deHCl removal of 1,1,1-difluorochloroethane as raw material, with the following reaction: CH3CF2Cl → CH2=CF2 + HCl. Currently, this process boasts ideal conversion rates and selectivity for vinylidene fluoride, produces few byproducts, and offers flexible production options, allowing manufacturers to choose the appropriate cracking process based on their technological strengths. The equipment is also relatively simple and easy to maintain. However, the production of feedstock 142b requires two additional reaction steps: first, acetylene reacts with hydrogen fluoride to produce 1,1-difluoroethane (HFC-152a), followed by photochlorination of 152a to 142b, as follows:

[0004] C2H2 + 2HF → CH3CHF2 (152a)

[0005] CH3CHF2+Cl2→CF2ClCH3(142b)+HCl

[0006] Although this process is currently quite common, its overall process is complex, energy consumption is high, production costs are high, and investment is also large. The pyrolysis tubes used in the pyrolysis process have a short service life and are prone to carbon and coking inside the tubes, which has obvious limitations.

[0007] In summary, both the production and preparation of vinylidene fluoride (VEF) originate from HCFC-142b. However, the catalytic dehydrogenation of VEF monomers using R152a offers higher energy efficiency. This route eliminates the need for a separate chlorination process, avoids the use of highly hazardous chlorine gas, and prevents the emission of the highly corrosive byproduct HCl at the source. Furthermore, the catalyst is less prone to coking during the reaction, eliminating the cumbersome steps of periodic coking cleaning of the cracking tubes. The process route is also relatively simple. Unfortunately, thermodynamic calculations show that R152a cannot be directly subjected to high-temperature cracking and dehydrogenation. Therefore, to achieve the direct preparation of VEF from R152a, the reaction pathway must be redesigned, and a highly efficient R152a dehydrogenation catalyst must be developed and prepared. Summary of the Invention

[0008] The purpose of this invention is to provide a method for simultaneously preparing vinylidene fluoride and vinyl fluoride; the method uses difluoroethane as a raw material and reacts it under the action of a catalyst and an oxidizing gas to simultaneously prepare vinylidene fluoride and vinyl fluoride.

[0009] The technical solution of the present invention is as follows:

[0010] A method for simultaneously preparing vinylidene fluoride and vinyl fluoride, the method comprising: reacting difluoroethane with a catalyst and an oxidizing gas to prepare vinylidene fluoride and vinyl fluoride; wherein the catalyst comprises an active component and a support compound, the active component comprising active component A, or the active component comprising active component A and active component B.

[0011] The active component A is selected from at least one of molybdenum salt, lanthanum salt, nickel salt, chromium salt, vanadium salt, platinum salt, or palladium salt;

[0012] The active component B is selected from at least one of sodium salt, potassium salt, cesium salt, magnesium salt, or calcium salt.

[0013] The technical principle of this invention is as follows: Active component A can activate the CH bonds in the difluoroethane molecule, reducing the activation energy required for the reaction, promoting the dehydrogenation reaction, and preventing excessive product reaction leading to reduced selectivity. Active component B can enhance the basicity of the catalyst surface, which is beneficial to the adsorption of raw material molecules on the catalyst surface, resulting in a better dehydrogenation reaction. However, its ability to activate CH bonds is relatively poor. Therefore, the main function of active component B is to enhance the dehydrogenation performance of the catalyst and improve the selectivity of the product vinylidene chloride.

[0014] When the active component includes active component A and active component B, the selectivity of vinylidene fluoride is greater than 50%.

[0015] The total loading of the active components in the catalyst is 0.1% to 30%, the loading of active component A in the catalyst is 0.1% to 25%, and the loading of active component B in the catalyst is 0% to 5%.

[0016] The loading of the active component in a catalyst refers to the content of metal elements in the catalyst.

[0017] Preferably, the total loading of the active components in the catalyst is 1% to 10%, the loading of active component A in the catalyst is 1% to 6%, and the loading of active component B in the catalyst is 0% to 5%.

[0018] Preferably, the total loading of active components in the catalyst is 1%–7%, the loading of active component A is 1%–6%, and the loading of active component B is 0–1%. Active component A is selected from lanthanum nitrate, palladium chloride, platinum chloride, or chromium nitrate, and active component B is selected from sodium chloride or sodium nitrate. Under these process conditions, the conversion rate of difluoroethane is at least 90%, and the total selectivity for olefins is greater than 80%.

[0019] Preferably, the total loading of active components in the catalyst is 4%–7%, the loading of active component A is 2%–6%, and the loading of active component B is 1%–2%. Active component A is selected from sodium vanadate, lanthanum nitrate, palladium chloride, chloroplatinic acid, palladium chloride, or ammonium molybdate, and active component B is selected from potassium chloride, sodium chloride, magnesium chloride, or calcium chloride. Under these process conditions, the conversion rate of difluoroethane is at least 75%, and the selectivity for vinylidene fluoride is greater than 60%.

[0020] The oxidizing gas is selected from at least one of oxygen, carbon dioxide, or nitrous oxide.

[0021] The carrier compound is selected from at least one of titanium oxide, silicon carbide, boron nitride, or molecular sieves. The molecular sieve carrier is SAPO aluminophosphorus molecular sieve, and the aluminosilicate molecular sieve includes one or more of ZSM molecular sieve, SSZ molecular sieve, and Y-type molecular sieve, more preferably SAPO-34, ZSM-5, ZSM-22, and SSZ-13 molecular sieves, and most preferably SAPO-34 and ZSM-22 molecular sieves.

[0022] The catalyst is prepared by impregnating a support compound in a soluble salt containing an active component, followed by drying, calcination, and tableting.

[0023] The soluble salt of active component A is selected from the chloride, nitrate, ammonium, or sodium salts of molybdenum, lanthanum, nickel, chromium, vanadium, platinum, or palladium; such as ammonium molybdate, molybdenum chloride, sodium molybdate; lanthanum nitrate; nickel chloride, nickel nitrate; chromium acetate, chromium nitrate, chromium chloride; sodium vanadate, vanadium chloride, vanadium nitrate; platinum chloride, chloroplatinic acid; palladium chloride.

[0024] The soluble salt of active component B is selected from the chloride, sulfate or nitrate salts of sodium, potassium, cesium, magnesium or calcium; such as sodium chloride, sodium sulfate, sodium nitrate; potassium chloride, potassium sulfate, potassium nitrate; cesium chloride, cesium nitrate; magnesium chloride, magnesium nitrate; calcium chloride, calcium bisulfate.

[0025] The calcination process involves placing the dried catalyst precursor in a muffle furnace and maintaining it at a specified temperature for a specific duration. The calcination temperature is 300–800°C, preferably 600–700°C; the calcination time is 2–12 hours, preferably 4–6 hours; air is introduced into the muffle furnace during the calcination process, or protective gases such as nitrogen or argon may be introduced.

[0026] The tableting process involves the catalyst being compressed at a pressure of 10–25 MPa, preferably 15–20 MPa; after tableting, the catalyst is crushed and sieved to a mesh size of 10–20.

[0027] Preferably, the method includes: using a mixture of difluoroethane, an oxidizing gas, and an inert gas as a co-gas for the reaction, at a gas hourly space velocity (GHSV) of 500-20000 mL / g. cat The reaction is carried out at a temperature of 300-800℃.

[0028] The co-entrant gas contains: oxygen 1.0%-35.0%, preferably 5.0%-20.0%; partial pressure controlled at 0.01-2.0 MPa, preferably 0.1-0.5 MPa. Nitrogen comprises 20.0%-95.0%, preferably 40.0%-90.0%, more preferably 60.0%-85.0%; partial pressure controlled at 0.01-2.0 MPa, preferably 0.1-0.5 MPa.

[0029] The preferred GHSV concentration is 5000-15000 mL / g cat The temperature is preferably 400-600℃; the catalytic reaction tube is made of one of quartz, stainless steel, or iron-chromium alloy, preferably quartz; the catalyst contact time is 0.5-20.0s, preferably 1.0-5.0s;

[0030] The present invention has the following advantages:

[0031] 1. This invention differs from traditional vinylidene fluoride preparation technology by realizing the one-step conversion of difluoroethane to directly synthesize high-value-added vinylidene fluoride, and simultaneously preparing vinyl fluoride. Furthermore, the selectivity of vinylidene fluoride and vinyl fluoride can be controlled by adjusting the type and content of active components in the catalyst during the preparation process.

[0032] 2. The reaction of this invention involves oxidizing gases, which can significantly promote the conversion of raw material R152a, with an overall conversion rate of up to 95% or more;

[0033] 3. The product of this invention has a high selectivity for polyvinylidene fluoride, at least 30%, and up to 60% or more. The total selectivity for olefins can reach more than 70%. It has a high space-time yield, short reaction time, and obvious economic benefits.

[0034] 4. The catalyst used in this invention can efficiently catalyze the dehydrogenation of difluoroethane to produce vinylidene fluoride, and it is inexpensive and can be used in industrial production, thus having significant socio-economic value. Detailed Implementation

[0035] The present invention will be further illustrated by the following examples, but these examples do not limit the scope of the invention.

[0036] Unless otherwise specified, all reagents used in the following examples and comparative examples are of analytical grade.

[0037] The method for catalytic dehydrogenation of difluoroethane to simultaneously prepare vinylidene fluoride and vinyl fluoride is as follows: Difluoroethane is used as the reactant. The gas flow rate is set to 10.0 mL / min, the oxygen flow rate to 5.0 mL / min, and the nitrogen flow rate to 15.0 mL / min. After the three are mixed evenly, they are introduced into a preheater at a temperature of 200℃. The mixed gases are then introduced into a fixed-bed reactor. The reaction tube is made of quartz with an inner diameter of 12.0 mm and a length of 500.0 mm. 1.0 g of the catalyst described in the examples below is packed into the tube, with a size of 10-20 mesh. Before the preparation begins, the catalyst is pretreated by heating and purging with inert gas for 3 h at a gas flow rate of 50.0 mL / min. After pretreatment, the preparation begins. The catalyst performance indicators are calculated as shown below. The preparation results are summarized in Table 1, and the comparative preparation results are summarized in Table 2.

[0038] The conversion (Conv.) of difluoroethane (R152a) and the selectivity (VDF Sel.) of vinylidene fluoride were calculated using the following formulas.

[0039]

[0040] The catalyst evaluation device involved in this embodiment of the invention includes an online gas chromatograph. During the reaction process, the composition of the gaseous products in the reactor is monitored and analyzed in real time by online gas chromatography.

[0041] Example 1

[0042] Weigh 0.71g of sodium vanadate and dissolve it in 10.0mL of deionized water. After stirring for 30min, add 4.5g of HY molecular sieve support and 40.0mL of deionized water to mix the system evenly. Then, heat the mixture to 80.0℃ at a rate of 3℃ / min while stirring. When the crude catalyst reaches a slurry state, transfer it to an oven and dry it at 120℃ for at least 6h. Afterward, place the system in a muffle furnace and heat it to 800.0℃ at a rate of 5℃ / min. Calcinate the catalyst at this temperature for 6h. After cooling, compress the catalyst into tablets, crush them, and sieve them to a mesh size of 10-20.

[0043] During the preparation process, the bed temperature was controlled at 600℃. The gaseous products were detected and analyzed by online gas chromatography. The results are shown in Table 1. The conversion rate of difluoroethane was 79.6%, the selectivity of vinylidene fluoride was 41.3%, the selectivity of vinyl fluoride was 40.3%, and the total selectivity of olefins was 81.6%. In this embodiment, difluoroethane was successfully catalytically converted into vinylidene fluoride in one step.

[0044] Example 2

[0045] Weigh 0.71g of sodium vanadate and dissolve it in 20.0mL of deionized water. After stirring for 30min, add 0.16g of potassium chloride and mix. Continue stirring for 2h. Then add 4.5g of HY molecular sieve support and 30.0mL of deionized water to mix the system evenly. Then heat the mixture to 80.0℃ at a rate of 3℃ / min while stirring. When the crude catalyst is in a slurry state, transfer it to an oven and dry it at 120℃ for at least 6h. After that, place the system in a muffle furnace and heat it to 800.0℃ at a rate of 5℃ / min. Calcinate it at this temperature for 6h. After cooling, compress the catalyst into tablets, crush them, and sieve them to 10-20 mesh.

[0046] During the preparation process, the bed temperature was controlled at 600℃. The gaseous products were detected and analyzed by online gas chromatography. The results are shown in Table 1. The conversion rate of difluoroethane was 75.0%, the selectivity of vinylidene fluoride was 62.3%, the selectivity of vinyl fluoride was 21.1%, and the total selectivity of olefins was 83.4%. In this embodiment, the addition of active component B significantly improved the selectivity of the target product.

[0047] Example 3-15

[0048] The experimental parameters used in the method described in Example 1 or 2 are slightly different from those in Example 1 or 2. The following is a description of each example, and the results are shown in Table 1.

[0049] The preparation process of Example 3 was the same as that of Example 2, except that the reagents added were 0.78 g of lanthanum nitrate and 0.12 g of sodium chloride, and the support compound was replaced with boron nitride at a dosage of 4.6 g. All other conditions remained unchanged. Under the conditions of this series of examples, the difluoroethane conversion rate was 90.2%, the selectivity for vinylidene fluoride was 68.6%, the selectivity for vinyl fluoride was 21.3%, and the total olefin selectivity was 89.9%.

[0050] The preparation process of Example 4 was the same as that of Example 1, except that 0.44 g of nickel chloride was added as the reagent, and the carrier compound was replaced with boron nitride at a dosage of 4.6 g, while other conditions remained unchanged. Under the conditions of this series of examples, the difluoroethane conversion rate was 81.1%, the selectivity for vinylidene fluoride was 44.6%, the selectivity for vinyl fluoride was 40.3%, and the total selectivity for olefins was 84.9%.

[0051] The preparation process of Example 5 was the same as that of Example 2, except that the reagents added were 0.78 g of chromium acetate and 0.33 g of cesium nitrate, and the support compound was replaced with titanium oxide at a dosage of 4.4 g. All other conditions remained unchanged. Under the conditions of this series of examples, the difluoroethane conversion rate was 86.7%, the selectivity for vinylidene fluoride was 59.3%, the selectivity for vinyl fluoride was 19.3%, and the total olefin selectivity was 78.6%.

[0052] The preparation process of Example 6 was the same as that of Example 1, except that the reagent added was 0.56g of ammonium molybdate, and the support compound was replaced with silicon carbide at a dosage of 4.8g, while other conditions remained unchanged. Under the conditions of this series of examples, the conversion rate of difluoroethane was 77.8%, the selectivity of vinylidene fluoride was 52.6%, the selectivity of vinyl fluoride was 36.6%, the total selectivity of olefins was 89.2%, and there were also a small amount of byproducts.

[0053] The preparation process of Example 7 was the same as that of Example 2, except that the reagents added were 0.42 g of chloroplatinic acid and 0.38 g of magnesium chloride, and the support compound was replaced with titanium dioxide at a dosage of 4.8 g. All other conditions remained unchanged. Under the conditions of this series of examples, the difluoroethane conversion rate was 84.5%, the selectivity for vinylidene fluoride was 64.7%, the selectivity for vinyl fluoride was 20.6%, and the total olefin selectivity was 85.3%.

[0054] The preparation process of Example 8 was the same as that of Example 2, except that the reagents added were 0.16 g of palladium chloride and 0.32 g of calcium chloride, and the support compound was replaced with HY molecular sieve at a dosage of 4.8 g. All other conditions remained unchanged. Under the conditions of this series of examples, the difluoroethane conversion rate was 85.7%, the selectivity for vinylidene fluoride was 67.1%, the selectivity for vinyl fluoride was 11.3%, and the total olefin selectivity was 78.4%.

[0055] The preparation process of Example 9 was the same as that of Example 1, except that 0.16 g of palladium chloride was added as the reagent, and the support compound was replaced with HY molecular sieve at a dosage of 4.8 g. All other conditions remained unchanged. Under the conditions of this series of examples, the difluoroethane conversion rate was 94.3%, the selectivity for vinylidene fluoride was 30.9%, the selectivity for vinyl fluoride was 49.2%, and the total selectivity for olefins was 80.1%.

[0056] The preparation process of Example 10 was the same as that of Example 2, except that the reagents added were 0.56 g of ammonium molybdate and 0.16 g of potassium chloride, and the carrier compound was replaced with titanium dioxide at a dosage of 4.4 g. All other conditions remained unchanged. Under the conditions of this series of examples, the difluoroethane conversion rate was 84.7%, the selectivity for vinylidene fluoride was 64.3%, the selectivity for vinyl fluoride was 28.1%, the total selectivity for olefins was 92.4%, and there were also a small amount of byproducts.

[0057] The preparation process of Example 11 was the same as that of Example 1, except that 0.46 g of molybdenum chloride was added as the reagent, and the support compound was replaced with ZSM-5 molecular sieve at a dosage of 4.6 g, while other conditions remained unchanged. Under the conditions of this series of examples, the difluoroethane conversion rate was 94.4%, the selectivity for vinylidene fluoride was 45.7%, the selectivity for vinyl fluoride was 30.8%, and the total selectivity for olefins was 76.5%.

[0058] The preparation process of Example 12 was the same as that of Example 2, except that the reagents added were 0.78 g of nickel nitrate and 0.41 g of cesium chloride, and the support compound was replaced with SAPO-34 molecular sieve at a dosage of 4.8 g. All other conditions remained unchanged. Under the conditions of this series of examples, the difluoroethane conversion rate was 84.9%, the selectivity for vinylidene fluoride was 59.3%, the selectivity for vinyl fluoride was 31.4%, and the total olefin selectivity was 90.7%.

[0059] The preparation process of Example 13 was the same as that of Example 2, except that the reagents added were 0.28 g of platinum chloride and 0.12 g of sodium nitrate, and the support compound was replaced with SSZ-13 molecular sieve at a dosage of 4.7 g. All other conditions remained unchanged. Under the conditions of this series of examples, the difluoroethane conversion rate was 92.4%, the selectivity for vinylidene fluoride was 57.6%, the selectivity for vinyl fluoride was 36.3%, and the total olefin selectivity was 93.9%.

[0060] The preparation process of Example 14 was the same as that of Example 1, except that 0.46 g of vanadium nitrate was added as a reagent, while other conditions remained unchanged. Under the conditions of this series of examples, the conversion rate of difluoroethane was 84.5%, the selectivity for vinylidene fluoride was 46.3%, the selectivity for vinyl fluoride was 26.8%, and the total selectivity for olefins was 73.1%.

[0061] The preparation process of Example 15 was the same as that of Example 1, except that 0.32 g of chromium nitrate was added as the reagent, and the carrier compound was replaced with boron nitride at a dosage of 4.8 g, while other conditions remained unchanged. Under the conditions of this series of examples, the difluoroethane conversion rate was 93.2%, the selectivity for vinylidene fluoride was 50.9%, the selectivity for vinyl fluoride was 33.4%, and the total selectivity for olefins was 84.3%.

[0062] The preparation process of Example 16 was the same as that of Example 1, except that 0.78 g of lanthanum nitrate was added as the reagent, and the support compound was replaced with boron nitride at a dosage of 4.6 g, while other conditions remained unchanged. Under the conditions of this series of examples, the difluoroethane conversion rate was 88.7%, the selectivity for vinylidene fluoride was 52.2%, the selectivity for vinyl fluoride was 31.4%, and the total selectivity for olefins was 83.6%.

[0063] Table 1. Properties of the products prepared in Examples 1-15

[0064]

[0065]

[0066] Comparative Example 1

[0067] Comparative Example 1 was conducted in the same manner as Example 1, except that an excess of ammonium molybdate (1.12 g) was added, while other conditions remained unchanged. Under the experimental conditions of this comparative example, the selectivity of vinylidene fluoride decreased significantly to only 2.9%. Excess molybdenum agglomerates during calcination, reducing the specific surface area of ​​the catalyst and thus decreasing the exposed active sites, resulting in poor catalyst performance. This indicates that the loading of active component A in this invention has a significant impact on controlling the selectivity of vinylidene fluoride.

[0068] Comparative Example 2

[0069] Comparative Example 2 was conducted in the same manner as Example 2, except that the addition of ammonium molybdate was omitted, while other conditions remained unchanged. No vinylidene fluoride was observed to form under the experimental conditions of this comparative example. Clearly, the enhancing effect of active component B requires the presence of active component A to be effective, indicating that active component A is a decisive factor in this invention.

[0070] Comparative Example 3

[0071] Comparative Example 1 was performed in the same manner as Example 2, except that an excess of potassium chloride (0.96 g) was added, while other conditions remained unchanged. Under the experimental conditions of this comparative example, the selectivity of vinylidene fluoride also showed a significant decrease, reaching only 4.2%. Excessive alkaline metal ions may cause the catalyst to become too alkaline, resulting in excessively strong molecular forces in the adsorbed products, preventing timely desorption after dehydrogenation and leading to over-dehydrogenation. This indicates that when the active component includes active component B, its loading has a significant impact on controlling the selectivity of vinylidene fluoride.

[0072] Comparative Example 4

[0073] Comparative Example 4 was performed in the same manner as Example 2, except that a support was not used; all other conditions remained unchanged. No vinylidene fluoride was observed to be produced under the experimental conditions of this comparative example. Clearly, the support is the key substance for dispersing the active component.

[0074] Table 2. Properties of the products prepared in Comparative Examples 1-4

[0075]

Claims

1. A method for simultaneously preparing vinylidene fluoride and vinyl fluoride, characterized in that, The method includes: reacting difluoroethane with a catalyst and an oxidizing gas to prepare vinylidene fluoride and vinyl fluoride; the catalyst includes an active component and a support compound, the active component includes active component A, or the active component includes active component A and active component B; The active component A is selected from at least one of molybdenum salt, lanthanum salt, nickel salt, chromium salt, vanadium salt, platinum salt, or palladium salt; The active component B is selected from at least one of sodium salt, potassium salt, cesium salt, magnesium salt, or calcium salt.

2. The method for simultaneously preparing vinylidene fluoride and vinyl fluoride by catalytic dehydrogenation of difluoroethane according to claim 1, characterized in that, The total loading of active components in the catalyst is 0.1% to 30%, the loading of active component A in the catalyst is 0.1% to 25%, and the loading of active component B in the catalyst is 0% to 5%.

3. The method for simultaneously preparing vinylidene fluoride and vinyl fluoride by catalytic dehydrogenation of difluoroethane according to claim 1, characterized in that, The total loading of the active components in the catalyst is 1% to 10%, the loading of active component A in the catalyst is 1% to 6%, and the loading of active component B in the catalyst is 0% to 5%.

4. The method for simultaneously preparing vinylidene fluoride and vinyl fluoride by catalytic dehydrogenation of difluoroethane according to claim 1, characterized in that, The oxidizing gas is selected from at least one of oxygen, carbon dioxide, or nitrous oxide.

5. The method for simultaneously preparing vinylidene fluoride and vinyl fluoride by catalytic dehydrogenation of difluoroethane according to claim 1, characterized in that, The carrier compound is selected from at least one of titanium oxide, silicon carbide, boron nitride, or molecular sieve.

6. The method for simultaneously preparing vinylidene fluoride and vinyl fluoride by catalytic dehydrogenation of difluoroethane according to any one of claims 1-5, characterized in that, The catalyst is prepared by impregnating a support compound in a soluble salt containing an active component, followed by drying, calcination, and tableting.

7. The method for simultaneously preparing vinylidene fluoride and vinyl fluoride by catalytic dehydrogenation of difluoroethane according to claim 6, characterized in that, The soluble salt of active component A is selected from the chloride, nitrate, ammonium, or sodium salts of molybdenum, lanthanum, nickel, chromium, vanadium, platinum, or palladium; the soluble salt of active component B is selected from the chloride, sulfate, or nitrate salts of sodium, potassium, cesium, magnesium, or calcium.

8. The method for simultaneously preparing vinylidene fluoride and vinyl fluoride by catalytic dehydrogenation of difluoroethane according to claim 6, characterized in that, The calcination temperature is 300–800°C, and the tableting is performed under a pressure of 10–25 MPa.

9. The method for simultaneously preparing vinylidene fluoride and vinyl fluoride by catalytic dehydrogenation of difluoroethane according to any one of claims 1-5, characterized in that, The method includes: mixing difluoroethane, an oxidizing gas, and an inert gas as a co-entrant for the reaction, at a gas hourly space velocity of 500-20000 mL / g. cat The reaction is carried out at a temperature of 300-800℃.

10. The method for simultaneously preparing vinylidene fluoride and vinyl fluoride by catalytic dehydrogenation of difluoroethane according to claim 9, characterized in that, In the co-entry gas: the proportion of oxygen is 1.0%-35.0%, and the partial pressure is controlled at 0.01-2.0 MPa; the proportion of nitrogen is 20.0%-95.0%, preferably 40.0%-90.0%; and the partial pressure of difluoroethane is controlled at 0.01-2.0 MPa.

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