A process for the preparation of hexafluorobutadiene

Abstract

The application discloses a preparation method of hexafluorobutadiene, and comprises the following steps: under the action of a catalyst, trifluorobromoethylene and trifluorovinyl zinc bromide are coupled in a reactor to obtain hexafluorobutadiene, wherein the catalyst is a cuprous salt catalyst, and the reaction temperature is 25-150 DEG C. The application has the advantages of simple operation, low raw material cost, high product yield and the like.

Description

Technical Field

[0001] This invention relates to fluorine-containing electronic gases, and particularly to a method for preparing hexafluorobutadiene. Background Technology

[0002] Hexafluorobutadiene, chemical name: 1,1,2,3,4,4-hexafluorobutadiene, English name: Hexafluorobutadiene, also known as perfluorobutadiene, abbreviated as HFBD, has a low fluorine-to-carbon ratio (F:C = 1.5), ODP is 0, and GWP is 0. 100 With a pH of 290 and an atmospheric lifetime of only 1.9 days, it exhibits excellent environmental performance, making it a low-greenhouse-effect, environmentally friendly etching gas and an important synthetic intermediate. Hexafluorobutadiene is widely used globally, particularly in high-end chip etching, and its preparation and purification processes have become a research hotspot in recent years.

[0003] Currently, the main processes for preparing hexafluorobutadiene include:

[0004] I. Zinc Reagent Coupling Process

[0005] Patent CN110590495A from Fujian Hangfu Electronic Materials Co., Ltd. discloses a method for preparing hexafluorobutadiene, specifically including: 1) hydrogenation reaction of trifluorochloroethylene as raw material under the action of a catalyst to obtain trifluoroethylene; 2) addition of trifluoroethylene with liquid bromine to obtain 1,2-dibromo-1,1,2-trifluoroethane, and then dehydrobromination with alkaline solution to obtain trifluorobromoethylene; 3) reaction of trifluorobromoethylene in a reaction vessel containing solvent, initiator and zinc powder to generate zinc reagent trifluorovinyl zinc bromide; 4) coupling reaction of trifluorovinyl zinc bromide with copper chloride and copper bromide to obtain hexafluorobutadiene.

[0006] Beijing Yuji Technology Development Co., Ltd.'s patent CN104844411A discloses a method for preparing hexafluorobutadiene using tetrafluoroethane (HFC-134a) as a raw material. This method involves first preparing the intermediate trifluorovinyl zinc, and then using a zinc reagent in Fe... 3+ Hexafluorobutadiene was obtained by coupling under certain conditions.

[0007] Burton's group (Tetrahedron Lett. 43 (2002) 2731-2733) disclosed a method using HFC-134a as a raw material, reacting it with zinc chloride in the presence of a strong base such as LDA (diisopropylaminolithium) to obtain trifluorovinyl zinc chloride, which then undergoes a coupling reaction under the catalysis of copper bromide to generate hexafluorobutadiene.

[0008] However, the zinc reagent coupling process requires the initial raw materials to be synthesized in multiple steps to obtain a highly active zinc reagent. Finally, the zinc reagent (zinc trifluorovinyl chloride / zinc trifluorovinyl bromide) is used to self-couple the zinc reagent to prepare hexafluorobutadiene under the action of an excess metal coupling catalyst. During the self-coupling process, two molecules of zinc reagent are required to generate one molecule of hexafluorobutadiene, resulting in low yield per unit volume. At the same time, an excess of coupling catalyst needs to be added during the production process, which increases the cost of raw materials and solid waste treatment.

[0009] II. Zinc Powder Dehalogenation Process

[0010] Patent CN112250541A of the 718 Research Institute of China Shipbuilding Industry Corporation discloses a method for preparing hexafluorobutadiene by dehalogenation of zinc powder, specifically including: 1) reacting iodine monochloride and trifluorochloroethylene to prepare 1,2-dichloro-2-iodo-1,1,2-trifluoroethane; 2) placing 1,2-dichloro-2-iodo-1,1,2-trifluoroethane and activated zinc into a reactor, then adding a polar base liquid and an ester catalyst to react and obtain 1,2,3,4-tetrachlorohexafluorobutane; 3) dehalogenating 1,2,3,4-tetrachlorohexafluorobutane and zinc powder to obtain hexafluorobutadiene.

[0011] Patent CN113061074A from Shanghai Chemical Industry Research Institute Co., Ltd. discloses a method for obtaining hexafluorobutadiene products by using 3,4-dichlorohexafluoro-1-butene as raw material and reacting it with zinc powder in an organic solvent.

[0012] However, the zinc powder dehalogenation process requires excessive zinc powder feeding, resulting in some waste and increased production costs. More importantly, zinc powder has a high density and is insoluble in solvents, making it prone to uneven distribution in the solution. Some zinc powder can accumulate at the bottom of the reactor, causing blockages and making post-processing very difficult.

[0013] III. Coupling process of trifluoroethylene and zinc reagent

[0014] Patent CN111187145A from the Electric Power Research Institute of Guangdong Power Grid Co., Ltd. discloses a method in which 1,1-dibromotetrafluoroethane is used as a raw material, and in an aprotic polar solvent in the presence of aluminum trihalide, it reacts with zinc powder to generate an organozinc reagent; then, under the action of a palladium catalyst, the zinc reagent reacts with trifluorobromoethylene to generate hexafluorobutadiene.

[0015] Zhejiang Lantian Environmental Protection High-Tech Co., Ltd.'s patent CN111320526A discloses a method for preparing hexafluorobutadiene by coupling trifluoroethylene bromide and trifluorovinyl zinc bromide under the action of a composite catalyst of precious metal palladium salt and organophosphorus compound.

[0016] However, the coupling of trifluorobromoethylene and zinc reagent requires the use of the precious metal palladium, which is expensive and difficult to reuse in the reaction, resulting in high production costs. Summary of the Invention

[0017] To address the aforementioned technical problems, this invention proposes a method for preparing hexafluorobutadiene that features a simple reaction process, low raw material costs, high product yield, and suitability for industrial production.

[0018] The objective of this invention is achieved through the following technical solution:

[0019] A method for preparing hexafluorobutadiene, the method comprising: heating trifluoroethylene bromide and trifluorovinyl zinc bromide in a reactor under the action of a catalyst, followed by a coupling reaction to obtain hexafluorobutadiene, the reaction formula being as follows:

[0020]

[0021] The reaction is carried out under heating, with a reaction temperature of 25–150°C, preferably 60–130°C, more preferably 80–110°C, and most preferably 80–100°C.

[0022] The catalyst is a cuprous salt catalyst, selected from at least one of cuprous halide, cuprous sulfate, cuprous carbonate, cuprous acetate, cuprous nitride, cuprous cyanide, cuprous oxide, cuprous sulfide, cuprous thiocyanate, or cuprous trifluoromethanesulfonate. Preferably, the catalyst is selected from at least one of cuprous halide, cuprous sulfate, cuprous carbonate, cuprous acetate, cuprous cyanide, cuprous oxide, or cuprous trifluoromethanesulfonate. More preferably, the catalyst is selected from at least one of cuprous bromide, cuprous chloride, cuprous iodide, or cuprous cyanide.

[0023] Unlike the coupling reaction of two parts of trifluorovinyl zinc bromide under low temperature conditions in the prior art, the present invention, under the action of cuprous salt catalyst, allows one part of trifluorovinyl zinc bromide to undergo a coupling reaction with one part of trifluoroethylene bromide under heating conditions, thereby improving the utilization rate of zinc reagent, reducing costs, and reducing the amount of waste.

[0024] In the reaction process of this invention, the cuprous salt catalyst can convert the trifluorovinyl zinc bromide reagent into the trifluorovinyl copper reagent. The use of the more active trifluorovinyl copper reagent is more conducive to the occurrence of the trifluoroethylene bromide coupling reaction.

[0025] Specifically, the molar ratio of the trifluorovinyl zinc bromide to the cuprous salt catalyst is 1:(0.05-2.0), preferably 1:(0.05-1.2), and more preferably 1:(0.05-0.2).

[0026] Furthermore, the molar ratio of trifluoroethylene bromide to trifluoroethylene zinc bromide is (0.8-10):1, preferably (1-8):1, and more preferably (1-2):1.

[0027] In the reaction process of this invention, trifluorovinyl zinc bromide is added to the reactor in the form of a trifluorovinyl zinc bromide solution, which is formed by dissolving trifluorovinyl zinc bromide in an organic solvent, wherein the organic solvent is a polar aprotic solvent. Preferably, the organic solvent is selected from at least one of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, 1,3-dimethyl-2-imidazolinone, N-methylpyrrolidone, diethyl ether, acetonitrile, or tetrahydrofuran. More preferably, the organic solvent is selected from at least one of N,N-dimethylformamide, N,N-dimethylacetamide, or tetrahydrofuran.

[0028] To ensure the stability of the raw material trifluorovinyl zinc bromide and prevent the decomposition of trifluorovinyl zinc bromide into trifluoroethylene, the introduced trifluoroethylene bromide is a gas, and the water content of the trifluoroethylene bromide gas is less than 2000 ppm, preferably less than 1000 ppm, and more preferably less than 500 ppm.

[0029] Furthermore, in the trifluorovinyl zinc bromide solution, the mass ratio of trifluorovinyl zinc bromide to the organic solvent is 1:(3-12), preferably 1:(3-5).

[0030] In the reaction process of this invention, it is preferably carried out in the presence of an inert gas, which is selected from at least one of nitrogen, argon, and helium. When the reaction system is under inert gas protection, the inert gas can prevent the cuprous salt catalyst from being oxidized and maintain its catalytic activity, while preventing oxygen from entering and causing the decomposition of trifluoroethylene.

[0031] According to the above-described method for preparing hexafluorobutadiene, the present invention includes the following steps in sequence:

[0032] 1) The step of adding a cuprous salt catalyst to the reactor, wherein the cuprous salt catalyst is a solid, a solid powder, or a cuprous salt solution;

[0033] 2) The step of adding trifluorovinyl zinc bromide solution to the reactor;

[0034] 3) The step of introducing trifluoroethylene into the reactor and heating it to the reaction temperature to carry out the reaction.

[0035] In step 3), the preferred reaction temperature is 80–130°C, and the preferred reaction time is 6 hours. After the reaction is complete, the temperature is raised to 130°C to evaporate all the gas, which is then collected with liquid nitrogen and hydrazine. The product, hexafluorobutadiene, is found in the collected gas.

[0036] The method for preparing hexafluorobutadiene according to the present invention can be a batch reaction or a continuous reaction, and the corresponding reactor can be a batch reactor or a tubular reactor.

[0037] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0038] 1. This invention uses an inexpensive and readily available cuprous salt catalyst to achieve the coupling of trifluoroethylene bromide and trifluorovinyl zinc bromide to prepare hexafluorobutadiene under heating conditions. Compared with the process of self-coupling of trifluorovinyl zinc bromide to prepare hexafluorobutadiene, it not only reduces the amount of zinc reagent used, but also reduces the raw material cost and the amount of waste, while improving the raw material utilization rate and product yield.

[0039] 2. The coupling process of the present invention is simple, uses inexpensive and readily available raw materials, and is suitable for industrial scale-up. Detailed Implementation

[0040] The present invention will be further described below with reference to specific embodiments, but the invention is not limited to these specific embodiments. Those skilled in the art should recognize that the present invention covers all alternatives, improvements, and equivalents that may be included within the scope of the claims.

[0041] Example 1

[0042] This embodiment provides a method for preparing hexafluorobutadiene, the method comprising the following steps:

[0043] 5.7 g (0.04 mol) of cuprous bromide was added to a 1000 mL reactor. Then, 450 g (20% by mass, 0.4 mol) of a solution of trifluorovinyl zinc bromide in N,N-dimethylformamide was added. 77.2 g (0.48 mol, water content less than 500 ppm) of trifluoroethylene bromide was then introduced. After the trifluoroethylene bromide was completely introduced, the reaction temperature was controlled at 80 °C and the reaction was maintained for 6 hours. After the reaction was completed, the temperature was raised to 130 °C, and all the gas was distilled off. 57.3 g of the gas was collected using a liquid nitrogen cold trap. Gas chromatography analysis revealed the following gas composition: hexafluorobutadiene 85.54%, trifluoroethylene bromide 10.20%, trifluoroethylene 3.56%, and other components 0.70%. Based on trifluorovinyl zinc bromide, the reaction yield was calculated to be 75.6%.

[0044] Example 2

[0045] The operation in this embodiment is the same as in Example 1, except that 4.0 g (0.04 mol) of cuprous chloride is used instead of 5.7 g (0.04 mol) of cuprous bromide as the cuprous salt catalyst, while other conditions remain unchanged. After the reaction is complete, 55.6 g of gas is collected in a liquid nitrogen cold trap. Gas chromatography analysis shows the following gas composition: hexafluorobutadiene 81.30%, trifluorobromoethylene 11.50%, trifluoroethylene 4.70%, and other components 2.50%.

[0046] The reaction yield was calculated to be 69.7% based on trifluorovinyl zinc bromide.

[0047] Example 3

[0048] The operation in this embodiment is the same as in Example 1, except that 7.6 g (0.04 mol) of cuprous iodide was used instead of 5.7 g (0.04 mol) of cuprous bromide as the cuprous salt catalyst, while other conditions remained unchanged. After the reaction was completed, 56.6 g of gas was collected in a liquid nitrogen cold trap. Gas chromatography analysis revealed the following gas composition: hexafluorobutadiene 83.75%, trifluorobromoethylene 11.06%, trifluoroethylene 3.22%, and other components 1.97%.

[0049] The calculated reaction yield was 73.1% based on trifluorovinyl zinc bromide.

[0050] Example 4

[0051] The operation in this embodiment is the same as in Example 1, except that 3.6 g (0.04 mol) of cuprous cyanide was used instead of 5.7 g (0.04 mol) of cuprous bromide as the cuprous salt catalyst, while other conditions remained unchanged. After the reaction was completed, 52.7 g of gas was collected in a liquid nitrogen cold trap. Gas chromatography analysis revealed the following gas composition: hexafluorobutadiene 76.20%, trifluorobromoethylene 15.6%, trifluoroethylene 3.50%, and other components 4.70%.

[0052] The calculated reaction yield was 62.0% based on trifluorovinyl zinc bromide.

[0053] Example 5

[0054] The operation in this embodiment is the same as in Example 1, except that 450g of a 20% (0.4mol) dimethyl sulfoxide solution of zinc trifluorovinyl bromide is used instead of 450g of a 20% (0.4mol) N,N-dimethylformamide solution of zinc trifluorovinyl bromide, while other conditions remain unchanged. After the reaction is complete, 50.0g of gas is collected in a liquid nitrogen cold trap. Gas chromatography analysis shows the following gas composition: hexafluorobutadiene 75.60%, trifluoroethylene bromide 15.30%, trifluoroethylene 3.44%, and other components 5.66%.

[0055] The calculated reaction yield was 58.3% based on trifluorovinyl zinc bromide.

[0056] Example 6

[0057] 5.7 g (0.04 mol) of cuprous bromide was added to a 1000 mL reactor. Then, 450 g (20% by mass, 0.4 mol) of a solution of trifluoroethylene zinc bromide in N,N-dimethylformamide was added, followed by 150 g of N,N-dimethylformamide solution and 77.2 g (0.48 mol) of trifluoroethylene bromide. After the trifluoroethylene bromide was completely introduced, the reaction temperature was controlled at 80 °C and maintained for 6 hours. After the reaction was completed, the temperature was raised to 130 °C, and all the gas was distilled off. 59.4 g of the gas was collected using a liquid nitrogen cold trap. Gas chromatography analysis revealed the following gas composition: hexafluorobutadiene 88.30%, trifluoroethylene bromide 7.43%, trifluoroethylene 3.67%, and other components 0.60%.

[0058] The reaction yield was calculated to be 80.9% based on trifluorovinyl zinc bromide.

[0059] Example 7

[0060] 5.7 g (0.04 mol) of cuprous bromide was added to a 1000 mL reactor. Then, 450 g (20% by mass, 0.4 mol) of a solution of trifluoroethylene zinc bromide in N,N-dimethylformamide was added to the reactor. Another 450 g of N,N-dimethylformamide solution was added, followed by the introduction of 77.2 g (0.48 mol, water content <500 ppm) of trifluoroethylene bromide. After the trifluoroethylene bromide was completely introduced, the reaction temperature was controlled at 80 °C and the reaction was maintained for 6 hours. After the reaction was completed, the temperature was raised to 130 °C, and all the gas was distilled off. 60.2 g of the gas was collected using a liquid nitrogen cold trap. Gas chromatography analysis revealed the following gas composition: hexafluorobutadiene 89.40%, trifluoroethylene bromide 5.50%, trifluoroethylene 4.70%, and other components 0.40%.

[0061] The calculated reaction yield was 83.1% based on trifluorovinyl zinc bromide.

[0062] Example 8

[0063] The operation in this embodiment is the same as in Example 1, except that the amount of trifluorobromoethylene is increased from 77.2g to 128.7g, while other conditions remain unchanged. After the reaction is complete, 102.6g of gas is collected using a liquid nitrogen cold trap. Gas chromatography analysis shows the following gas composition: hexafluorobutadiene 56.00%, trifluorobromoethylene 40.00%, trifluoroethylene 2.10%, and other components 1.90%.

[0064] The calculated reaction yield was 88.7% based on zinc trifluorovinyl bromide.

[0065] Example 9

[0066] The operation in this embodiment is the same as in Embodiment 1, except that the reaction temperature is increased from 80℃ to 110℃, while other conditions remain unchanged. After the reaction is complete, 54.2g of gas is collected using a liquid nitrogen cold trap. Gas chromatography analysis reveals the following gas composition: hexafluorobutadiene 55.30%, trifluorobromoethylene 16.3%, trifluoroethylene 9.8%, and other components 18.6%.

[0067] The calculated reaction yield was 46.2% based on trifluorovinyl zinc bromide.

[0068] Example 10

[0069] The operation in this embodiment is the same as in Embodiment 1, except that the reaction temperature is increased from 80℃ to 100℃, while other conditions remain unchanged. After the reaction is complete, 55.2g of gas is collected using a liquid nitrogen cold trap. Gas chromatography analysis reveals the following gas composition: hexafluorobutadiene 80.30%, trifluorobromoethylene 8.70%, trifluoroethylene 8.8%, and other components 2.2%.

[0070] The reaction yield was calculated to be 68.4% based on trifluorovinyl zinc bromide.

[0071] Example 11

[0072] The operation in this embodiment is the same as in Example 1, except that the amount of cuprous bromide is 28.7 g (0.2 mol), while other conditions remain unchanged. After the reaction is complete, 60.3 g of gas is collected using a liquid nitrogen cold trap. Gas chromatography analysis shows the following gas composition: hexafluorobutadiene 87.55%, trifluorobromoethylene 9.50%, trifluoroethylene 2.75%, and other components 0.2%.

[0073] The reaction yield was calculated to be 81.5% based on trifluorovinyl zinc bromide.

[0074] Example 12

[0075] The operation in this embodiment is the same as in Example 1, except that the amount of cuprous bromide is 57.4 g (0.4 mol), while other conditions remain unchanged. After the reaction is complete, 62.4 g of gas is collected using a liquid nitrogen cold trap. Gas chromatography analysis shows the following gas composition: hexafluorobutadiene 90.55%, trifluorobromoethylene 6.50%, trifluoroethylene 2.20%, and other components 0.75%.

[0076] The reaction yield was calculated to be 87.2% based on trifluorovinyl zinc bromide.

[0077] Comparative Example 1

[0078] The operation of this comparative example was the same as in Example 1, except that 3.2 g (0.04 mol) of copper oxide was used instead of the cuprous salt catalyst, while other conditions remained unchanged. After the reaction was completed, 66.7 g of gas was collected in a liquid nitrogen cold trap. Gas chromatography analysis revealed the following gas composition: hexafluorobutadiene 9.80%, trifluorobromoethylene 78.3%, trifluoroethylene 2.3%, and other components 9.6%.

[0079] The reaction yield was calculated to be 10.1% based on trifluorovinyl zinc bromide.

[0080] Comparative Example 2

[0081] The operation of this comparative example was the same as in Example 1, except that 3.9 g (0.04 mol) of copper hydroxide was used instead of the cuprous salt catalyst, while other conditions remained unchanged. After the reaction was completed, 63.2 g of gas was collected in a liquid nitrogen cold trap. Gas chromatography analysis revealed the following gas composition: 0.10% hexafluorobutadiene, 92.4% trifluorobromoethylene, 2.98% trifluoroethylene, and 4.52% other components.

[0082] The reaction yield was calculated to be 0.10% based on trifluorovinyl zinc bromide.

[0083] Comparative Example 3

[0084] The operation in this embodiment is the same as in Embodiment 1, except that the reaction temperature is reduced from 80°C to 5°C, while other conditions remain unchanged. After the reaction is complete, 70.2g of gas is collected using a liquid nitrogen cold trap. Gas chromatography analysis reveals the following gas composition: hexafluorobutadiene 0.80%, trifluorobromoethylene 95.1%, trifluoroethylene 3.6%, and other components 0.5%.

[0085] The reaction yield was calculated to be 0.87% based on trifluorovinyl zinc bromide.

[0086] Comparative Example 4

[0087] 450 g (20% by mass, 0.4 mol) of N,N-dimethylformamide solution of trifluorovinyl zinc bromide was added to a 1000 mL reactor. The reaction system was cooled to -5 °C, and 64.5 g of CuCl2 was added to the reactor through a feeding funnel. The reaction temperature was controlled below 0 °C by controlling the feeding rate of CuCl2. After the reaction was completed for 2 hours, the temperature was raised to 130 °C, and all the gas was distilled off. 24.8 g of the gas was collected in a liquid nitrogen cold trap. Gas chromatography analysis showed the following gas composition: hexafluorobutadiene 91.0%, trifluoroethylene bromide 4.5%, trifluoroethylene 2.5%, and other components 2.0%.

[0088] The reaction yield was calculated to be 69.6% based on trifluorovinyl zinc bromide.

[0089] Comparative Example 5

[0090] The operation in this embodiment is the same as in Embodiment 1, except that the water content of trifluorobromoethylene is 5000 ppm, while other conditions remain unchanged. After the reaction is complete, 60.3 g of gas is collected using a liquid nitrogen cold trap. Gas chromatography analysis reveals the following gas composition: hexafluorobutadiene 54.70%, trifluorobromoethylene 17.80%, trifluoroethylene 25.30%, and other components 2.20%.

[0091] The calculated reaction yield was 50.9% based on trifluorovinyl zinc bromide.

Claims

1. A method for preparing hexafluorobutadiene, characterized in that: The preparation method includes: under the action of a catalyst, trifluoroethylene bromide and trifluorovinyl zinc bromide undergo a coupling reaction in a reactor to obtain hexafluorobutadiene. Trifluorovinyl zinc bromide is added to the reactor in the form of a trifluorovinyl zinc bromide solution, which is formed by dissolving trifluorovinyl zinc bromide in an organic solvent. The catalyst is a cuprous salt catalyst, and the reaction temperature is 60–130°C. The catalyst is selected from at least one of cuprous halide, cuprous sulfate, cuprous carbonate, cuprous acetate, cuprous nitride, cuprous cyanide, cuprous oxide, cuprous sulfide, cuprous thiocyanate, or cuprous trifluoromethanesulfonate. The trifluoroethylene bromide is trifluoroethylene bromide gas with a water content of less than 2000 ppm. The preparation of hexafluorobutadiene is carried out under an inert gas atmosphere.

2. The method for preparing hexafluorobutadiene according to claim 1, characterized in that: The catalyst is selected from at least one of cuprous halide, cuprous sulfate, cuprous carbonate, cuprous acetate, cuprous cyanide, cuprous oxide, or cuprous trifluoromethanesulfonate.

3. The method for preparing hexafluorobutadiene according to claim 1, characterized in that: The reaction temperature is 80–110°C.

4. The method for preparing hexafluorobutadiene according to claim 1, characterized in that: In the preparation method, the organic solvent is selected from at least one of N,N-dimethylformamide, N,N-dimethylacetamide, hexamethylphosphoramide, dimethyl sulfoxide, 1,3-dimethyl-2-imidazolinone, N-methylpyrrolidone, diethyl ether, acetonitrile, or tetrahydrofuran.

5. The method for preparing hexafluorobutadiene according to claim 4, characterized in that: The water content of the trifluorobromoethylene is less than 1000 ppm.

6. The method for preparing hexafluorobutadiene according to claim 4, characterized in that: The water content of the trifluorobromoethylene is less than 500 ppm.

7. The method for preparing hexafluorobutadiene according to claim 4, characterized in that: In the trifluorovinyl zinc bromide solution, the mass ratio of trifluorovinyl zinc bromide to organic solvent is 1:(3-12).

8. The method for preparing hexafluorobutadiene according to claim 1, characterized in that: The molar ratio of trifluoroethylene bromide to trifluorovinyl zinc bromide is (0.8–10):

1.

9. The method for preparing hexafluorobutadiene according to claim 1, characterized in that: The molar ratio of trifluorovinyl zinc bromide to the catalyst is 1:(0.05~2.0).

10. The method for preparing hexafluorobutadiene according to claim 1, characterized in that: The preparation method includes the following steps in sequence: The step of adding a cuprous salt catalyst to the reactor, wherein the cuprous salt catalyst is a solid or a cuprous salt solution; The step of adding trifluorovinyl zinc bromide solution to the reactor; The step involves introducing trifluoroethylene bromide into the reactor and heating it to the reaction temperature to carry out the reaction.

11. The method for preparing hexafluorobutadiene according to claim 1, characterized in that: The reactor is either a batch reactor or a tubular reactor.

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