Method for synthesizing hexafluorobutadiene in one step

Abstract

The invention belongs to the technical field of chemical synthesis, and particularly relates to a method for synthesizing hexafluorobutadiene in one step. According to the invention, chlorotrifluoroethylene is used as a raw material, and the hexafluorobutadiene is prepared by continuous flow hydrodehydrochlorination coupling reaction under the action of the catalyst, so that the synthesis method is extremely simplified, and the required product hexafluorobutadiene can be synthesized by only one step. According to the method disclosed by the invention, the problems of long operation period, large equipment investment and the like of the existing process are solved, the production period is shortened, the production efficiency is improved, and loss and pollution possibly caused by intermediate links are reduced. Meanwhile, the simplified synthesis method is easy for industrial operation, is suitable for large-scale industrial production, and provides an efficient, economic and environment-friendly new way for the production of hexafluorobutadiene.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical synthesis, and particularly relates to a method for synthesizing hexafluorobutadiene in one step. Background Art

[0002] Hexafluorobutadiene is also known as hexafluoro-1,3-butadiene, perfluorobutadiene, codenamed FC-2316 or R2316, and its molecular formula is C 4 F 6 It is a colorless, odorless, toxic, flammable and compressible gas at room temperature and pressure. It is insoluble in water and has an average lifespan of 1.9 days in the atmosphere. It has a very low global warming potential and zero ozone depletion. 4 F 6 It is mainly used in plasma etching processing technology of semiconductor products and dry etching of ultra-large-scale integrated circuits. Compared with traditional fluorine-containing electronic gases, hexafluorobutadiene has advantages such as precise etching and green environmental protection. It is the only product among etching gases that has both application performance and environmental protection performance. Therefore, it is considered to be an ideal product to replace traditional electronic etching gases. With the development of the integrated circuit industry and the attention to greenhouse gases, hexafluorobutadiene with the best etching effect and environmentally friendly characteristics is bound to become a leading product and be widely used in the laser etching agent market.

[0003] At present, there are many methods for preparing hexafluorobutadiene, mainly including the dimerization reaction of 1,2-difluorodichloroethylene with elemental fluorine, addition, coupling and dechlorination of trifluorochloroethylene, polymerization of tetrafluoroethylene, gas phase fluorination of 1,2,3,4-tetrachlorobutane with elemental fluorine, CF 2 =CFZnBr coupling and the synthesis of CF using 1,1,1,2-tetrafluoroethane (HFC-134a) as raw material 2 =CFZnCl and then coupled to obtain hexafluorobutadiene and other process routes.

[0004] Using chlorofluoroethylene as a raw material, a fluorination dimerization reaction occurs with fluorine or chlorine to generate a tetrahalogen hexafluorobutane intermediate, which is then dechlorinated to obtain hexafluorobutadiene. CN101910096A discovered a method of using vinyl chloride as a raw material, through a fluorination dimerization reaction with elemental fluorine, a fluorination addition, and then dehalogenation or dehydrohalogenation to obtain a target product. The fluorination dimerization reaction is carried out in the presence of a liquid organic solvent, the dehydrohalogenation process is carried out in an inorganic base or organic base solution, and the dehalogenation is achieved by reacting with a transition metal in the presence of a solvent. The process route is complex, the reaction conditions are harsh, and the cost is high.

[0005] CN102399128 discloses a method for preparing hexafluorobutadiene, wherein 1,1,2-tribromotrifluoroethane reacts with zinc powder or magnesium powder in the presence of a non-protonic organic solvent to obtain a metal organic compound of trifluorovinyl bromide, and then a metal halide is added dropwise to obtain C4 F 6 The metal halide salt in the process is chloride or bromide of trivalent iron or divalent copper. This method has the advantages of high selectivity, easy purification and low pollution, but the preparation process consumes an equal amount of metal Zn, which is relatively costly.

[0006] CN101525267 provides a method for preparing hexafluorobutadiene using fluorovinyl zinc bromide as an intermediate. The specific process is: adding zinc powder and a non-protonic polar solvent into a reactor protected by an inert gas, controlling the temperature to 50-90°C, and then adding 1,1-dibromotetrafluoroethane to generate trifluorovinyl zinc bromide; trifluorovinyl zinc bromide undergoes a coupling reaction under the action of a catalyst to generate C 4 F 6 Although this process has the advantages of short steps, simple process and few by-products, it also has disadvantages such as high raw material prices, harsh reaction conditions, relatively low yields, and difficult to handle reagents.

[0007] CN105399599 proposes to use 1,1-dichloro-1,2,2-trifluoroethane or 1,2-dichloro-1,1,2-trifluoroethane as raw materials in H 2 The target product hexafluorobutadiene is separated by a hydrodechlorination dimerization reaction on a supported metal catalyst under an atmosphere, and the intermediate product hydrofluorochlorobutane is subjected to gas phase thermal cracking to remove HCl to obtain hexafluorobutadiene. Although this method has the advantages of high raw material conversion rate and simple process, it also has the disadvantages of complicated steps, high reaction temperature, high energy consumption, and low yield. Moreover, its raw material Freon is an ozone depleting substance and faces large-scale production cuts.

[0008] Therefore, how to provide a method for preparing hexafluorobutadiene with cheap and easily available raw materials, milder reaction, high yield, simple process, fewer steps and easy industrialization is a technical problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0009] In view of this, the present invention discloses a method for synthesizing hexafluorobutadiene in one step, which is a method for preparing hexafluorobutadiene with cheap and easily available raw materials, milder reaction, high yield, simple process, fewer steps and easy industrialization.

[0010] In order to achieve the above object, the present invention adopts the following technical solution:

[0011] A method for synthesizing hexafluorobutadiene in one step, the method being as follows:

[0012] Chlorotrifluoroethylene was added into the tubular reactor and H 2, a continuous flow hydrodehydrochlorination coupling reaction is carried out in a tubular reactor under the action of a catalyst, and a high-purity hexafluorobutadiene product is obtained after alkali washing, water washing, drying, compression, and distillation purification.

[0013] Furthermore, the H 2 The feed ratio of trifluoroethylene to chlorotrifluoroethylene is 1 to 10:1, preferably 5:1.

[0014] Furthermore, the catalyst needs to be pretreated before the reaction, and the pretreatment method is as follows:

[0015] After the catalyst was loaded into the tubular reactor, H 2 , the catalyst bed temperature was increased from room temperature to 250°C at a heating rate of 5°C / min, and the catalyst was reduced at 250°C for 3 hours.

[0016] The synthesis process of the present invention is:

[0017]

[0018] Furthermore, the reactions can be carried out simultaneously in the same reactor with the same catalyst, or in two series reactions.

[0019] It should be noted that the reaction raw material chlorotrifluoroethylene is first subjected to a hydrogenation reaction under the action of a catalyst, and the obtained intermediate product does not need to be separated, and then subjected to a dehydrochlorination reaction to finally generate the target product hexafluorobutadiene.

[0020] Furthermore, the catalyst is an AB type bifunctional catalyst supported on the same carrier; wherein,

[0021] The molar ratio of A to B is 1:(0.5-2), and the weight ratio of AB to the carrier is (0.05-0.2):1;

[0022] And, A is a transition metal; B is a metal salt;

[0023] The carrier is at least activated carbon, CdO, AlF 3 、Al 2 O 3 、CeO 2 , graphite, SiO 2 One of them.

[0024] Furthermore, the temperature of the hydrodehydrochlorination coupling reaction is 25-250°C, preferably 100-250°C, the reaction pressure is normal pressure, and the space velocity is 200-3000h -1 .

[0025] It should be noted that the hydrodehydrochlorination coupling reaction at 25-250° C. not only reduces the energy consumption required for the reaction process to the maximum extent, but also ensures the conversion rate of chlorotrifluoroethylene and the selectivity of hexafluorobutadiene to the maximum extent, and prolongs the service life of the catalyst.

[0026] Furthermore, the active component in the catalyst component A is at least one of Pd, Pt, Rh, and Raney Ni, and the catalyst component B is AlCl 3 , AlF 2 MgF 2 、MnO 3 、ZrO 2 At least one of the carriers, wherein the carrier is at least activated carbon, CdO, AlF 3 、Al 2 O 3 、CeO 2 , graphite, SiO 2 One of them.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. The present invention uses chlorotrifluoroethylene as a raw material. Chlorotrifluoroethylene is a widely available and relatively cheap substance that is easily available on the market. Its cheap and readily available characteristics not only reduce production costs, but also provide a solid material basis for large-scale industrial production, and have significant advantages in terms of raw material costs.

[0029] 2. In the present invention, the conversion rate of raw materials and the selectivity of products have reached a high level of more than 80%, which can make more effective use of raw materials, reduce waste, and reduce production costs. At the same time, the purity of the target product is ensured, the generation of by-products is reduced, and the subsequent separation and purification process is made simpler and more efficient, bringing higher economic benefits to industrial production.

[0030] 3. The reaction temperature of the present invention is controlled between 25 and 250°C, which is milder than other methods. Mild reaction conditions not only reduce the requirements for equipment, reduce equipment investment and maintenance costs, but also reduce energy consumption in the entire reaction process and extend the life of the catalyst, which not only meets the requirements of energy conservation and environmental protection, but also effectively reduces production costs and improves production efficiency.

[0031] 4. The preparation method of the present invention is extremely simplified, and the desired product hexafluorobutadiene can be prepared in only one step. This innovative method overcomes many problems of the existing process, such as long operation cycle and large equipment investment. The one-step preparation method not only shortens the production cycle and improves production efficiency, but also reduces the loss and pollution that may be caused by the intermediate links. At the same time, this simplified preparation method is easy to industrialize and is suitable for large-scale industrial production, providing a new way for the production of hexafluorobutadiene that is efficient, economical and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0033] Figure 1 It is the GC-MS detection spectrum of the hexafluorobutadiene synthesized by the present invention. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] The word "embodiment" used here as an "exemplary" does not necessarily mean that any embodiment described is superior to or better than other embodiments. Unless otherwise specified, the performance index tests in the embodiments of this application are performed using conventional test methods in the art. It should be understood that the terms described in this application are only used to describe specific implementation methods and are not used to limit the content disclosed in this application.

[0036] Unless otherwise specified, the technical and scientific terms used in this document have the same meanings as commonly understood by ordinary technicians in the technical field to which this application belongs; other experimental methods and technical means not specifically specified in this application refer to experimental methods and technical means commonly used by ordinary technicians in this field.

[0037] In order to better illustrate the content of the present application, numerous specific details are provided in the specific examples below. It should be understood by those skilled in the art that the present application can also be implemented without certain specific details. In the embodiments, some methods, means, instruments, equipment, etc. well known to those skilled in the art are not described in detail in order to highlight the main purpose of the present application.

[0038] Under the premise of no conflict, the technical features disclosed in the embodiments of the present application can be combined arbitrarily, and the resulting technical solutions belong to the contents disclosed in the embodiments of the present application.

[0039] The invention discloses a method for synthesizing hexafluorobutadiene in one step.

[0040] In order to better understand the present invention, the present invention is further specifically described below through the following examples, but it should not be understood as a limitation of the present invention. Some non-essential improvements and adjustments made by technicians in this field based on the above invention content are also considered to fall within the protection scope of the present invention.

[0041] Example 1

[0042] With chlorotrifluoroethylene and H 2 As the reaction raw material, hexafluorobutadiene is prepared by continuous flow hydrodehydrochlorination reaction. The specific preparation steps are as follows:

[0043] The reaction is carried out in a plug flow tubular reactor, the reaction tube of which is a nickel tube with an inner diameter of 16 mm and a length of 55 cm, and is placed in a tubular furnace for heating. 2 The flow rates of H 2 The flow rate was 550 mL / min, and the H 2 The flow rate ratio of the trifluorochloroethylene was 5, and 30 mL of Pd-AlCl 3 / Fixed reactor bed of activated carbon catalyst, the catalyst bed temperature is increased to 250°C at a heating rate of 5°C / min, the reaction pressure is normal pressure, the catalyst is reduced at 250°C for 3 hours, and the gas after the reaction is quenched, alkali washed, water washed, dried, and distilled to obtain the product.

[0044] Preparation of Pd-AlCl 3 / activated carbon catalyst method, comprising the following steps:

[0045] The palladium chloride is dissolved in deionized water according to a set ratio to prepare a uniform metal precursor solution; the activated carbon carrier is immersed in the solution and stirred at a constant temperature of 50°C for 2 hours to uniformly adsorb the metal precursor on the carrier surface; the impregnated carrier is dried at 120°C for 8 hours, and then placed in a hydrogen atmosphere and reduced at 300°C to obtain a catalyst loaded with metal palladium; aluminum chloride is dissolved in deionized water at a molar ratio of 1:1 to palladium to prepare a uniform solution, and the reduced catalyst is immersed in the solution and stirred at a constant temperature of 50°C for 2 hours to uniformly adsorb aluminum chloride on the carrier surface; finally, the impregnated catalyst is dried at 120°C for 8 hours to obtain Pd-AlCl 3 / activated carbon catalyst.

[0046] The product was identified as hexafluorobutadiene by GC-MS. The product was tested by gas chromatography and the actual purity of the product was calculated by external standard method. The consumption of chlorotrifluoroethylene was used as the basis for calculation. The selectivity of hexafluorobutadiene was 91.7% and the conversion rate of chlorotrifluoroethylene was 88.4%.

[0047] Implementation 2

[0048] With chlorotrifluoroethylene and H 2 As the reaction raw material, hexafluorobutadiene is prepared by continuous flow hydrodehydrochlorination reaction. The specific preparation steps are as follows:

[0049] The reaction is carried out in a plug flow tubular reactor, the reaction tube of which is a nickel tube with an inner diameter of 16 mm and a length of 55 cm, and is placed in a tubular furnace for heating. 2 The flow rates of H 2 The flow rate was 550 mL / min, and the H 2 The flow rate ratio of the trifluorochloroethylene was 4, and 30 mL of Pt-AlCl 3 / Al 2 O 3 The catalyst is fixed in the reactor bed, the catalyst bed temperature is increased to 250°C at a heating rate of 5°C / min, the reaction pressure is normal pressure, the catalyst is reduced at 250°C for 3 hours, and the gas after the reaction is quenched, alkali washed, water washed, dried, and distilled to obtain the product.

[0050] Preparation of Pt-AlCl 3 / Al 2 O 3 The method comprises the following steps: dissolving a certain mass proportion of chloroplatinic acid in deionized water to prepare a uniform metal precursor solution; 2 O 3 The carrier is immersed in the solution and stirred at a constant temperature of 50°C for 2 hours to ensure that the metal drive is uniformly adsorbed on the surface of the carrier; the impregnated carrier is dried at 120°C for 8 hours, and then placed in a hydrogen atmosphere and reduced at 350°C to obtain a catalyst loaded with metal platinum; aluminum chloride is dissolved in deionized water at a molar ratio of 1:1 to platinum to obtain a uniform aluminum chloride solution; the reduced catalyst is immersed in the aluminum chloride solution and stirred at a constant temperature of 50°C for 2 hours to allow aluminum chloride to be uniformly adsorbed on the surface of the carrier; the impregnated catalyst is dried at 120°C for 8 hours to obtain the final Pt-AlCl 3 / Al 2 O 3 catalyst.

[0051] The product was identified as hexafluorobutadiene by GC-MS. The product was tested by gas chromatography and the actual purity of the product was calculated by external standard method. The consumption of chlorotrifluoroethylene was used as the basis for calculation. The selectivity of hexafluorobutadiene was 73.6% and the conversion rate of chlorotrifluoroethylene was 84.5%.

[0052] Implementation 3

[0053] With chlorotrifluoroethylene and H 2 As the reaction raw material, hexafluorobutadiene is prepared by continuous flow hydrodehydrochlorination reaction. The specific preparation steps are as follows:

[0054] The reaction is carried out in a plug flow tubular reactor, the reaction tube of which is a nickel tube with an inner diameter of 16 mm and a length of 55 cm, and is placed in a tubular furnace for heating. 2 The flow rates of H 2 The flow rate was 550 mL / min, and the H 2 The flow rate ratio of the flow rate of trifluorochloroethylene was 6, and 45 mL of Rh-ZrO 2 / Al 2 O 3 The catalyst is fixed in the reactor bed, the catalyst bed temperature is increased to 250°C at a heating rate of 5°C / min, the reaction pressure is normal pressure, the catalyst is reduced at 250°C for 3 hours, and the gas after the reaction is quenched, alkali washed, water washed, dried, and distilled to obtain the product.

[0055] Preparation of Rh-ZrO 2 / Al 2 O 3 The method comprises the following steps: adding a certain proportion of chlororhodium acid (RhCl 3 ) was dissolved in deionized water to prepare a uniform metal precursor solution; Al 2 O 3 The carrier is immersed in the solution and stirred at a constant temperature of 50°C for 2 hours to allow the metal precursor to be uniformly adsorbed on the surface of the carrier; the impregnated carrier is taken out and dried at 120°C for 8 hours, then placed in a hydrogen atmosphere and reduced at 350°C to obtain a catalyst loaded with Rh; zirconium chloride is dissolved in deionized water at a molar ratio of 1:1.2 to rhodium to obtain a uniform zirconium chloride solution; Al 2 O 3 The support was immersed in the solution and stirred at 50 °C for 2 hours to ensure that ZrO 2 The impregnated carrier was calcined at 500 °C for 4 hours to obtain the final Rh-ZrO 2 / Al 2 O 3 catalyst.

[0056] The product was identified as hexafluorobutadiene by GC-MS. The product was tested by gas chromatography and the actual purity of the product was calculated by external standard method. The consumption of chlorotrifluoroethylene was used as the basis for calculation. The selectivity of hexafluorobutadiene was 76.3% and the conversion rate of chlorotrifluoroethylene was 85.7%.

[0057] Example 4

[0058] With chlorotrifluoroethylene and H 2 As the reaction raw material, hexafluorobutadiene is prepared by continuous flow hydrodehydrochlorination reaction. The specific preparation steps are as follows:

[0059] The reaction is carried out in a plug flow tubular reactor, the reaction tube of which is a nickel tube with an inner diameter of 16 mm and a length of 55 cm, and is placed in a tubular furnace for heating. 2 The flow rates of H 2 The flow rate was 550 mL / min, and the H 2 The flow rate ratio of the flow rate of trifluorochloroethylene was 7, and 45 mL of Pd-MnO 3 / Fixed reactor bed of activated carbon catalyst, the catalyst bed temperature is increased to 220°C at a heating rate of 5°C / min, the reaction pressure is normal pressure, the catalyst is reduced at 220°C for 3 hours, and the gas after the reaction is quenched, alkali washed, water washed, dried, and distilled to obtain the product.

[0060] Preparation of Pd-MnO 3 / activated carbon catalyst method, comprising the following steps: dissolving palladium chloride in deionized water in a certain proportion to prepare a uniform metal precursor solution; immersing an activated carbon carrier in the solution, and stirring at a constant temperature of 50°C for 2 hours, so that the metal precursor is uniformly adsorbed on the surface of the carrier; drying the impregnated carrier at 120°C for 8 hours, and then placing it in a hydrogen atmosphere, and performing a reduction treatment at 400°C to obtain a catalyst loaded with metal palladium; dissolving manganese nitrate in deionized water at a molar ratio of 1:1 to palladium to prepare a uniform solution, immersing the catalyst after the reduction treatment in the solution, and stirring at a constant temperature of 50°C for 2 hours, so that the manganese nitrate is uniformly adsorbed on the surface of the carrier; and finally calcining the impregnated catalyst at 400°C for 4 hours to obtain Pd-MnO 3 / activated carbon catalyst.

[0061] The product was identified as hexafluorobutadiene by GC-MS. The product was detected by gas chromatography. The purity of the actual content of the product was calculated by external standard method and reached over 99%. The selectivity of hexafluorobutadiene was 86.3% and the conversion rate of chlorotrifluoroethylene was 82.6% based on the consumption of chlorotrifluoroethylene.

[0062] Example 5

[0063] With chlorotrifluoroethylene and H 2 As the reaction raw material, hexafluorobutadiene is prepared by continuous flow hydrodehydrochlorination reaction. The specific preparation steps are as follows:

[0064] The reaction is carried out in a plug flow tubular reactor, the reaction tube of which is a nickel tube with an inner diameter of 16 mm and a length of 55 cm, and is placed in a tubular furnace for heating. 2 The flow rates of H 2 The flow rate was 550 mL / min, and the H 2 The flow rate ratio of the flow rate to the trifluorochloroethylene was 8, and 55 mL of Raney Ni-MgF 2 / Al 2 O 3 The catalyst is fixed in the reactor bed, and the catalyst bed temperature is increased to 220°C at a heating rate of 5°C / min. The reaction pressure is normal pressure. The catalyst is reduced at 220°C for 3 hours. After the reaction, the gas is quenched, washed with alkali, washed with water, dried, and purified by distillation to obtain the product.

[0065] Preparation of Raney Ni-MgF 2 / Al 2 O 3 The method comprises the following steps: dissolving a certain proportion of nickel nitrate in deionized water to prepare a uniform nickel precursor solution; 2 O 3 The carrier is immersed in the solution and stirred at a constant temperature of 50°C for 2 hours to ensure that the metal precursor is uniformly adsorbed on the surface of the carrier; the impregnated carrier is dried at 120°C for 8 hours and then calcined at 400°C for 4 hours to form nickel oxide; the calcined sample is placed in a hydrogen atmosphere and reduced at 500°C to obtain a catalyst loaded with metallic nickel; the catalyst is immersed in a 20% hydroxide solution and treated at 80°C for 2 hours to form a highly active Raney Ni structure; magnesium nitrate is dissolved in deionized water at a molar ratio of 1:1.5 to nickel to form a uniform magnesium salt solution, the treated carrier is added to the magnesium salt solution, stirred evenly, and ensure that the carrier is fully in contact with the magnesium salt solution; potassium fluoride solution is slowly added dropwise under stirring to react magnesium ions and fluoride ions to generate MgF 2 After the sample was dried at 120 °C for 8 h, the sample was calcined at 350 °C to obtain RaneyNi-MgF 2 / Al 2 O 3 catalyst.

[0066] The product was identified as hexafluorobutadiene by GC-MS. The product was detected by gas chromatography. The purity of the actual content of the product was calculated by external standard method and reached over 99%. The selectivity of hexafluorobutadiene was 89.4% and the conversion rate of chlorotrifluoroethylene was 76.8% based on the consumption of chlorotrifluoroethylene.

[0067] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A one-step method for synthesizing hexafluorobutadiene, characterized in that: The method is as follows: Chlorotrifluoroethylene is added into a tubular reactor, and H2 is introduced at the same time. A continuous flow hydrodehydrochlorination coupling reaction is carried out in the tubular reactor under the action of a catalyst. After alkali washing, water washing, drying, compression, and distillation purification, a high-purity hexafluorobutadiene product is obtained.

2. The one-step synthesis method of hexafluorobutadiene according to claim 1, characterized in that: The feed ratio of H2 to chlorotrifluoroethylene is 1 to 10:

1. The catalyst is pretreated before the reaction. The pretreatment method is as follows: After the catalyst was loaded into the tubular reactor, H2 was introduced, and the catalyst bed temperature was increased from room temperature to 250°C at a heating rate of 5°C / min, and the catalyst was reduced at 250°C for 3 hours.

3. The one-step synthesis method of hexafluorobutadiene according to claim 1 or 2, characterized in that: The catalyst is an AB type bifunctional catalyst supported on the same carrier; wherein, The molar ratio of A to B is 1:(0.5-2), and the weight ratio of AB to the carrier is (0.05-0.2):1; And, A is a transition metal; B is a metal salt; The carrier is at least one of activated carbon, CdO, AlF3, Al2O3, CeO2, graphite and SiO2.

4. The one-step synthesis method of hexafluorobutadiene according to claim 1 or 2, characterized in that: The temperature of the hydrodehydrochlorination coupling reaction is 25-250°C, the reaction pressure is normal pressure, and the space velocity is 200-3000h -1 .

5. The one-step synthesis method of hexafluorobutadiene according to claim 2, characterized in that: The feed ratio of H2 to chlorotrifluoroethylene is 5:

1.

6. The one-step synthesis method of hexafluorobutadiene according to claim 3, characterized in that: The active component in the catalyst component A is at least one of Pd, Pt, Rh and Raney Ni.

7. The one-step synthesis method of hexafluorobutadiene according to claim 3, characterized in that: The catalyst component B is at least one of AlCl3, MgF2, MnO3, and ZrO2.

8. The one-step synthesis method of hexafluorobutadiene according to claim 3, characterized in that: The carrier is at least one of activated carbon, CdO, AlF3, Al2O3, CeO2, graphite and SiO2.

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