Method for synthesizing dodecafluorodihydrohexane by catalytic hydrogenation of hexafluoropropylene dimer

Abstract

The application provides a method for synthesizing dodecafluorodihydrohexane by catalytic hydrogenation of hexafluoropropylene dimer, and belongs to the technical field of fluorine-containing chemical industry.The method uses hexafluoropropylene dimer as raw material to synthesize dodecafluorodihydrohexane by hydrogenation under the catalysis of a supported catalyst; in addition, the method discloses preparation of the supported catalyst, which is used for catalyzing the hydrogenation synthesis reaction of hexafluoropropylene dimer and hydrogen, and can effectively improve the conversion rate of the reaction and the selectivity of the product dodecafluorodihydrohexane 。

Description

Technical Field

[0001] This invention relates to the field of fluorinated chemical technology, and in particular to a method for the catalytic hydrogenation of hexafluoropropylene dimer to synthesize dodecafluorodihydrohexane. Background Technology

[0002] dodecafluorodihydrohexane (C6H2F) 12 It is an important intermediate of fluorinated fine chemicals. It does not contain chlorine atoms and has an ODP value of zero. It can replace CFC-113 as a cleaning agent and a coolant for large generator sets and electronic devices.

[0003] For example, patent document CN201010519726.8 discloses a catalyst for the catalytic hydrogenation of hexafluoropropylene dimer to prepare dodecafluorohexane. The catalyst consists of a main catalyst, an auxiliary agent, and a support: the main catalyst is Pd; the auxiliary agent is selected from one or more of La, Ce, Cu, Zn, or Ni; and the main catalyst and auxiliary agent are supported on a support. The catalyst disclosed in this invention exhibits high activity in the process of catalytic hydrogenation of hexafluoropropylene dimer to prepare dodecafluorohexane, can react at relatively low temperatures and pressures, and has simple operation, good stability, and does not involve a series of side reactions such as defluorination and re-hydrogenation.

[0004] For example, patent document CN109652819B discloses a method for preparing perfluorohexane, comprising: (1) using hexafluoropropylene dimer as raw material, catalytically hydrogenating it in a reactor to synthesize dodecylfluorodihydrohexane; (2) introducing the dodecylfluorodihydrohexane obtained in step (1), anhydrous hydrofluoric acid, and conductive additive dimethyl disulfide into an electrolytic cell, and preparing branched perfluorohexane by Simons electrochemical fluorination. The method of this invention uses perfluoropropylene dimer as raw material, first hydrogenating it to obtain saturated hydrofluoroalkanes, and then electrochemically fluorinating it to replace hydrogen to obtain branched perfluoroalkanes. The hydrogenation conversion rate is high and the selectivity is good, resulting in a significant improvement in electrochemical fluorination efficiency and a substantial reduction in production costs.

[0005] In summary, existing methods for preparing dodecafluorohexane from hexafluoropropylene dimer have some technical drawbacks, such as complex processes, low reaction conversion and selectivity, and the need for further separation and purification of the finished product. Summary of the Invention

[0006] (a) Technical problems to be solved

[0007] To address the shortcomings of existing technologies, this invention provides a method for the catalytic hydrogenation of hexafluoropropylene dimer to synthesize dodecafluorodihydrohexane, which improves product conversion rate and selectivity, thereby solving at least one of the technical problems mentioned in the background art, and belongs to the field of fluorine-containing chemical technology.

[0008] (II) Technical Solution

[0009] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0010] A method for the catalytic hydrogenation of hexafluoropropylene dimer to synthesize dodecafluorodihydrohexane includes the following steps:

[0011] S1: Hexafluoropropylene gas is introduced into a tubular reactor supported on catalyst 1, and the reaction temperature is controlled at 160-240℃ and the reaction time is 1-45s. After the reaction is completed, hexafluoropropylene dimer is obtained.

[0012] S2: The hexafluoropropylene dimer obtained in S1 and hydrogen are introduced into a fixed-bed reactor and hydrogenated under the catalysis of supported catalyst 2 to synthesize dodecafluorodihydrohexane.

[0013] Furthermore, in the above technical solution, the catalyst in S1 is selected from one or a mixture of several of AgF, NaF, KF, RbF or CsF, the catalyst loading is 5-25%, and the support is activated carbon, aluminum oxide, silicon dioxide or magnesium oxide.

[0014] Furthermore, in the above technical solution, the fixed-bed reactor in S2 has an inner diameter of 16-24mm, a length of 800-1000mm, and is made of stainless steel.

[0015] Furthermore, the preparation method of the supported catalyst 2 in S2 in the above technical solution is as follows:

[0016] Dry resin-based spherical activated carbon is soaked in the impregnation solution of the reactor for 2-5 hours. The mass ratio of catalyst support to impregnation solution is 1:5-1:10, and the loading time is 5-10 hours. The product is separated, dried, and placed in an exchange column. Fluorine gas is introduced through the column for treatment. The fluorine space velocity is 0.2-1 L / h, and the column time is 20-40 minutes. Then, nitrogen is used to replace the column for 60-120 minutes. The product is then removed to obtain supported catalyst 2.

[0017] Furthermore, the amount of resin-based spherical activated carbon packed in the above technical solution is 20-40% of the volume percentage of the exchange column.

[0018] Furthermore, the preparation method of the impregnation solution in the above technical solution is as follows:

[0019] Add 2-5 parts palladium nitrate, 0.5-2 parts rhodium nitrate, 0.2-2 parts 3,3',6,6'-tetracarboxylic acid-4,4'-bipyridine, 0.001-0.05 parts 3,5-bis(2,4-dicarboxyphenyl)pyridine, and 70-100 parts DMF by weight. Purge with nitrogen, heat to 50-60℃ and maintain constant temperature with stirring for 2-4 hours. Then add 0.02-0.5 parts aminopropylheptyl-cage polysilsesquioxane and 20-30 parts DMF. Heat to 50-60℃ and maintain constant temperature with stirring for 0.5-2 hours to obtain the impregnation solution.

[0020] Furthermore, in the above technical solution, the catalyst loading in S2, by weight percentage, is 0.05% to 15%.

[0021] Furthermore, in the above technical solution, the reaction temperature in S2 is 100-300℃, and the reaction pressure is 0.5-5MPa.

[0022] Furthermore, in the above technical solution, the volumetric flow ratio of hexafluoropropylene dimer to hydrogen in S2 is 1:1-9, and the space velocity is 45-80 h⁻¹. -1 .

[0023] Furthermore, in the above technical solution, the vacuum drying temperature in S4 is 75-95℃, and the vacuum degree is -0.06 to -0.1 MPa.

[0024] (III) Technical Effects

[0025] (1) By using this method to synthesize dodecafluorodihydrohexane by hydrogenation of hexafluoropropylene dimer as raw material under the catalysis of a supported catalyst, the process is simple, the raw materials are readily available, and it has the prospect of industrial production.

[0026] (2) This method prepared a supported catalyst for the hydrogenation synthesis reaction of hexafluoropropylene dimer and hydrogen, which significantly improved the conversion rate of the reaction and the selectivity of the product dodecylfluorodihydrohexane. Detailed Implementation

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] <Example 1>

[0029] A method for the catalytic hydrogenation of hexafluoropropylene dimer to synthesize dodecafluorodihydrohexane includes the following steps:

[0030] S1: Hexafluoropropylene gas is introduced into a tubular reactor supported on catalyst 1, and the reaction temperature is controlled at 160℃ for 36s. After the reaction is completed, hexafluoropropylene dimer is obtained.

[0031] S2: The hexafluoropropylene dimer obtained in S1 and hydrogen are introduced into a fixed-bed reactor and hydrogenated under the catalysis of supported catalyst 2 to synthesize dodecafluorodihydrohexane.

[0032] In the above technical solution, the catalyst in S1 is selected from AgF, the catalyst loading is 8%, and the support is activated carbon.

[0033] In the above technical solution, the fixed-bed reactor in S2 has an inner diameter of 20mm, a length of 900mm, and is made of stainless steel.

[0034] The preparation method of the supported catalyst 2 in S2 in the above technical solution is as follows:

[0035] Dry resin-based spherical activated carbon was soaked in the impregnation solution of the reactor for 2 hours. The mass ratio of catalyst support to impregnation solution was 1:5, and the loading time was 9 hours. The product was separated, dried, and placed in an exchange column. Fluorine gas was introduced through the column for treatment. The fluorine space velocity was 0.9 L / h, and the column time was 40 minutes. Then, nitrogen gas was used to replace the column for 60 minutes. The product was then removed to obtain supported catalyst 2.

[0036] The resin-based spherical activated carbon filling amount in the above technical solution is 20% of the volume percentage of the exchange column.

[0037] The method for preparing the impregnation solution described in the above technical solution is as follows:

[0038] Add 2g palladium nitrate, 0.5g rhodium nitrate, 0.2g 3,3',6,6'-tetracarboxylic acid-4,4'-bipyridine, 0.01g 3,5-bis(2,4-dicarboxyphenyl)pyridine, and 70g DMF. Purge with nitrogen gas, heat to 50℃ and maintain constant temperature with stirring for 4h. Then add 0.1g aminopropylheptyl-cage polysilsesquioxane and 20g DMF, heat to 50℃ and maintain constant temperature with stirring for 2h to obtain the impregnation solution.

[0039] The catalyst loading in S2 described in the above technical solution is 4% by weight.

[0040] In the above technical solution, the reaction temperature in S2 is 100℃ and the reaction pressure is 5MPa.

[0041] In the above technical solution, the volumetric flow ratio of hexafluoropropylene dimer to hydrogen in S2 is 1:3, and the space velocity is 75 h⁻¹. -1 .

[0042] In the above technical solution, the vacuum drying temperature in S4 is 75℃ and the vacuum degree is -0.06Mpa.

[0043] <Example 2>

[0044] A method for the catalytic hydrogenation of hexafluoropropylene dimer to synthesize dodecafluorodihydrohexane includes the following steps:

[0045] S1: Hexafluoropropylene gas is introduced into a tubular reactor supported on catalyst 1, and the reaction temperature is controlled at 200℃ for 26s. After the reaction is completed, hexafluoropropylene dimer is obtained.

[0046] S2: The hexafluoropropylene dimer obtained in S1 and hydrogen are introduced into a fixed-bed reactor and hydrogenated under the catalysis of supported catalyst 2 to synthesize dodecafluorodihydrohexane.

[0047] In the above technical solution, the catalyst in S1 is selected from KF, the catalyst loading is 14%, and the support is silicon dioxide.

[0048] In the above technical solution, the fixed-bed reactor in S2 has an inner diameter of 20mm, a length of 900mm, and is made of stainless steel.

[0049] The preparation method of the supported catalyst 2 in S2 in the above technical solution is as follows:

[0050] Dry resin-based spherical activated carbon was soaked in the impregnation solution of the reactor for 3 hours. The mass ratio of catalyst support to impregnation solution was 1:8, and the loading time was 7 hours. The product was separated, dried, and placed in an exchange column. Fluorine gas was introduced through the column for treatment. The fluorine space velocity was 0.6 L / h, and the column time was 30 minutes. Then, nitrogen gas was used to replace the column for 90 minutes. The product was then removed to obtain supported catalyst 2.

[0051] The resin-based spherical activated carbon filling amount in the above technical solution is 30% of the volume percentage of the exchange column.

[0052] The method for preparing the impregnation solution described in the above technical solution is as follows:

[0053] Add 3.5g palladium nitrate, 1.2g rhodium nitrate, 1.1g 3,3',6,6'-tetracarboxylic acid-4,4'-bipyridine, 0.03g 3,5-bis(2,4-dicarboxyphenyl)pyridine, and 85g DMF. Purge with nitrogen gas, heat to 55℃ and maintain constant temperature with stirring for 2-4 hours. Then add 0.32g aminopropylheptyl-cage polysilsesquioxane and 25g DMF, heat to 55℃ and maintain constant temperature with stirring for 1 hour to obtain the impregnation solution.

[0054] The catalyst loading in S2 described in the above technical solution is 9% by weight.

[0055] In the above technical solution, the reaction temperature in S2 is 200℃ and the reaction pressure is 3MPa.

[0056] In the above technical solution, the volumetric flow ratio of hexafluoropropylene dimer to hydrogen in S2 is 1:6, and the space velocity is 65 h⁻¹. -1 .

[0057] In the above technical solution, the vacuum drying temperature in S4 is 85℃ and the vacuum degree is -0.08Mpa.

[0058] <Example 3>

[0059] A method for the catalytic hydrogenation of hexafluoropropylene dimer to synthesize dodecafluorodihydrohexane includes the following steps:

[0060] S1: Hexafluoropropylene gas is introduced into a tubular reactor supported on catalyst 1, and the reaction temperature is controlled at 240℃ for 15s. After the reaction is completed, hexafluoropropylene dimer is obtained.

[0061] S2: The hexafluoropropylene dimer obtained in S1 and hydrogen are introduced into a fixed-bed reactor and hydrogenated under the catalysis of supported catalyst 2 to synthesize dodecafluorodihydrohexane.

[0062] In the above technical solution, the catalyst in S1 is selected from NaF, the catalyst loading is 22%, and the support is magnesium oxide.

[0063] In the above technical solution, the fixed-bed reactor in S2 has an inner diameter of 20mm, a length of 900mm, and is made of stainless steel.

[0064] The preparation method of the supported catalyst 2 in S2 in the above technical solution is as follows:

[0065] Dry resin-based spherical activated carbon was soaked in the impregnation solution of the reactor for 5 hours. The mass ratio of catalyst support to impregnation solution was 1:10, and the loading time was 5 hours. The product was separated, dried, and placed in an exchange column. Fluorine gas was introduced through the column for treatment. The fluorine space velocity was 0.2 L / h, and the column time was 20 minutes. Then, nitrogen gas was used to replace the column for 120 minutes. The product was then removed to obtain supported catalyst 2.

[0066] The resin-based spherical activated carbon filling amount in the above technical solution is 40% of the volume percentage of the exchange column.

[0067] The method for preparing the impregnation solution described in the above technical solution is as follows:

[0068] Add 5g palladium nitrate, 2g rhodium nitrate, 2g 3,3',6,6'-tetracarboxylic acid-4,4'-bipyridine, 0.05g 3,5-bis(2,4-dicarboxyphenyl)pyridine, and 100g DMF. Purge with nitrogen gas, heat to 60℃ and maintain constant temperature with stirring for 2h. Then add 0.5g aminopropylheptyl-cage polysilsesquioxane and 30g DMF, heat to 60℃ and maintain constant temperature with stirring for 0.8h to obtain the impregnation solution.

[0069] The catalyst loading in S2 described in the above technical solution is 15% by weight.

[0070] In the above technical solution, the reaction temperature in S2 is 300℃ and the reaction pressure is 0.8MPa.

[0071] In the above technical solution, the volumetric flow ratio of hexafluoropropylene dimer to hydrogen in S2 is 1:9, and the space velocity is 55 h⁻¹. -1 .

[0072] In the above technical solution, the vacuum drying temperature in S4 is 95℃ and the vacuum degree is -0.1Mpa.

[0073] <Comparative Example 1>

[0074] A method for the catalytic hydrogenation of hexafluoropropylene dimer to synthesize dodecafluorodihydrohexane includes the following steps:

[0075] S1: Hexafluoropropylene gas is introduced into a tubular reactor supported on catalyst 1, and the reaction temperature is controlled at 160℃ for 36s. After the reaction is completed, hexafluoropropylene dimer is obtained.

[0076] S2: The hexafluoropropylene dimer obtained in S1 and hydrogen are introduced into a fixed-bed reactor and hydrogenated under the catalysis of supported catalyst 2 to synthesize dodecafluorodihydrohexane.

[0077] In the above technical solution, the catalyst in S1 is selected from AgF, the catalyst loading is 8%, and the support is activated carbon.

[0078] In the above technical solution, the fixed-bed reactor in S2 has an inner diameter of 20mm, a length of 900mm, and is made of stainless steel.

[0079] The preparation method of the supported catalyst 2 in S2 in the above technical solution is as follows:

[0080] Dry resin-based spherical activated carbon was soaked in the impregnation solution of the reactor for 2 hours. The mass ratio of catalyst support to impregnation solution was 1:5, and the loading time was 9 hours. The product was separated, dried, and placed in an exchange column. Fluorine gas was introduced through the column for treatment. The fluorine space velocity was 0.9 L / h, and the column time was 40 minutes. Then, nitrogen gas was used to replace the column for 60 minutes. The product was then removed to obtain supported catalyst 2.

[0081] The resin-based spherical activated carbon filling amount in the above technical solution is 20% of the volume percentage of the exchange column.

[0082] The method for preparing the impregnation solution described in the above technical solution is as follows:

[0083] Add 2g palladium nitrate, 0.5g rhodium nitrate, 0.01g 3,5-bis(2,4-dicarboxyphenyl)pyridine, and 70g DMF. Purge with nitrogen gas, heat to 50℃ and maintain constant temperature with stirring for 4h. Then add 0.1g aminopropylheptyl-cage polysilsesquioxane and 20g DMF, heat to 50℃ and maintain constant temperature with stirring for 2h to obtain the impregnation solution.

[0084] The catalyst loading in S2 described in the above technical solution is 4% by weight.

[0085] In the above technical solution, the reaction temperature in S2 is 100℃ and the reaction pressure is 5MPa.

[0086] In the above technical solution, the volumetric flow ratio of hexafluoropropylene dimer to hydrogen in S2 is 1:3, and the space velocity is 75 h⁻¹. -1 .

[0087] In the above technical solution, the vacuum drying temperature in S4 is 75℃ and the vacuum degree is -0.06Mpa.

[0088] <Comparative Example 2>

[0089] A method for the catalytic hydrogenation of hexafluoropropylene dimer to synthesize dodecafluorodihydrohexane includes the following steps:

[0090] S1: Hexafluoropropylene gas is introduced into a tubular reactor supported on catalyst 1, and the reaction temperature is controlled at 160℃ for 36s. After the reaction is completed, hexafluoropropylene dimer is obtained.

[0091] S2: The hexafluoropropylene dimer obtained in S1 and hydrogen are introduced into a fixed-bed reactor and hydrogenated under the catalysis of supported catalyst 2 to synthesize dodecafluorodihydrohexane.

[0092] In the above technical solution, the catalyst in S1 is selected from AgF, the catalyst loading is 8%, and the support is activated carbon.

[0093] In the above technical solution, the fixed-bed reactor in S2 has an inner diameter of 20mm, a length of 900mm, and is made of stainless steel.

[0094] The preparation method of the supported catalyst 2 in S2 in the above technical solution is as follows:

[0095] Dry resin-based spherical activated carbon was soaked in the impregnation solution of the reactor for 2 hours. The mass ratio of catalyst support to impregnation solution was 1:5, and the loading time was 9 hours. The product was separated, dried, and placed in an exchange column. Fluorine gas was introduced through the column for treatment. The fluorine space velocity was 0.9 L / h, and the column time was 40 minutes. Then, nitrogen gas was used to replace the column for 60 minutes. The product was then removed to obtain supported catalyst 2.

[0096] The resin-based spherical activated carbon filling amount in the above technical solution is 20% of the volume percentage of the exchange column.

[0097] The method for preparing the impregnation solution described in the above technical solution is as follows:

[0098] Add 2g palladium nitrate, 0.5g rhodium nitrate, 0.2g 3,3',6,6'-tetracarboxylic acid-4,4'-bipyridine, and 70g DMF. Purge with nitrogen, heat to 50℃ and maintain constant temperature with stirring for 4h. Then add 0.1g aminopropylheptyl-cage polysilsesquioxane and 20g DMF, heat to 50℃ and maintain constant temperature with stirring for 2h to obtain the impregnation solution.

[0099] The catalyst loading in S2 described in the above technical solution is 4% by weight.

[0100] In the above technical solution, the reaction temperature in S2 is 100℃ and the reaction pressure is 5MPa.

[0101] In the above technical solution, the volumetric flow ratio of hexafluoropropylene dimer to hydrogen in S2 is 1:3, and the space velocity is 75 h⁻¹. -1 .

[0102] In the above technical solution, the vacuum drying temperature in S4 is 75℃ and the vacuum degree is -0.06Mpa.

[0103] <Comparative Example 3>

[0104] A method for the catalytic hydrogenation of hexafluoropropylene dimer to synthesize dodecafluorodihydrohexane includes the following steps:

[0105] S1: Hexafluoropropylene gas is introduced into a tubular reactor supported on catalyst 1, and the reaction temperature is controlled at 160℃ for 36s. After the reaction is completed, hexafluoropropylene dimer is obtained.

[0106] S2: The hexafluoropropylene dimer obtained in S1 and hydrogen are introduced into a fixed-bed reactor and hydrogenated under the catalysis of supported catalyst 2 to synthesize dodecafluorodihydrohexane.

[0107] In the above technical solution, the catalyst in S1 is selected from AgF, the catalyst loading is 8%, and the support is activated carbon.

[0108] In the above technical solution, the fixed-bed reactor in S2 has an inner diameter of 20mm, a length of 900mm, and is made of stainless steel.

[0109] The preparation method of the supported catalyst 2 in S2 in the above technical solution is as follows:

[0110] Dry resin-based spherical activated carbon was soaked in the impregnation solution of the reactor for 2 hours. The mass ratio of catalyst support to impregnation solution was 1:5, and the loading time was 9 hours. The product was separated, dried, and placed in an exchange column. Fluorine gas was introduced through the column for treatment. The fluorine space velocity was 0.9 L / h, and the column time was 40 minutes. Then, nitrogen gas was used to replace the column for 60 minutes. The product was then removed to obtain supported catalyst 2.

[0111] The resin-based spherical activated carbon filling amount in the above technical solution is 20% of the volume percentage of the exchange column.

[0112] The method for preparing the impregnation solution described in the above technical solution is as follows:

[0113] Add 2g palladium nitrate, 0.5g rhodium nitrate, 0.2g 3,3',6,6'-tetracarboxylic acid-4,4'-bipyridine, 0.01g 3,5-bis(2,4-dicarboxyphenyl)pyridine, and 70g DMF. Purge with nitrogen gas, heat to 50°C and maintain constant temperature with stirring for 6 hours to obtain the impregnation solution.

[0114] The catalyst loading in S2 described in the above technical solution is 4% by weight.

[0115] In the above technical solution, the reaction temperature in S2 is 100℃ and the reaction pressure is 5MPa.

[0116] In the above technical solution, the volumetric flow ratio of hexafluoropropylene dimer to hydrogen in S2 is 1:3, and the space velocity is 75 h⁻¹. -1 .

[0117] In the above technical solution, the vacuum drying temperature in S4 is 75℃ and the vacuum degree is -0.06Mpa.

[0118] Example Evaluation:

[0119] The synthesized products of the above embodiments and comparative examples were analyzed and tested by gas chromatography. The products were collected by low-temperature condensation. The reaction analysis results are shown in the table.

[0120] in:

[0121]

[0122]

[0123] Example 1 95.8 95.3 Example 2 98.1 96.7 Example 3 99.6 98.2 Comparative Example 1 90.3 91.4 Comparative Example 2 92.6 92.2 Comparative Example 3 86.6 90.2

[0124] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for the catalytic hydrogenation of hexafluoropropylene dimer to synthesize dodecafluorodihydrohexane, characterized in that, The following steps are included: S1: Hexafluoropropylene gas is introduced into a tubular reactor supported on catalyst 1, and the reaction temperature is controlled at 160-240℃ and the reaction time is 1-45s. After the reaction is completed, hexafluoropropylene dimer is obtained. S2: The hexafluoropropylene dimer obtained in S1 and hydrogen are introduced into a fixed-bed reactor and hydrogenated under the catalysis of supported catalyst 2 to synthesize dodecafluorodihydrohexane. The catalyst in S1 is selected from one or a mixture of several of AgF, NaF, KF, RbF or CsF, with a catalyst loading of 5-25%, and the support is activated carbon, aluminum oxide, silicon dioxide or magnesium oxide; The preparation method of the supported catalyst 2 in S2 is as follows: Dry resin-based spherical activated carbon is soaked in the impregnation solution of the reactor for 2-5 hours. The mass ratio of catalyst support to impregnation solution is 1:5-1:10, and the loading time is 5-10 hours. The product is separated, dried, and placed in an exchange column. Fluorine gas is introduced through the column for treatment. The fluorine space velocity is 0.2-1 L / h, and the column time is 20-40 minutes. Then, nitrogen is used to replace the column for 60-120 minutes. The product is then removed to obtain supported catalyst 2. The amount of resin-based spherical activated carbon packed is 20-40% of the volume percentage of the exchange column; The method for preparing the impregnation solution is as follows: Add 2-5 parts palladium nitrate, 0.5-2 parts rhodium nitrate, 0.2-2 parts 3,3',6,6'-tetracarboxylic acid-4,4'-bipyridine, 0.001-0.05 parts 3,5-bis(2,4-dicarboxyphenyl)pyridine, and 70-100 parts DMF by weight. Purge with nitrogen, heat to 50-60℃ and maintain constant temperature with stirring for 2-4 hours. Then add 0.02-0.5 parts aminopropylheptyl-cage polysilsesquioxane and 20-30 parts DMF. Heat to 50-60℃ and maintain constant temperature with stirring for 0.5-2 hours to obtain the impregnation solution. The catalyst loading in S2, by weight percentage, is 0.05% to 15%.

2. The method for catalytic hydrogenation of hexafluoropropylene dimer to synthesize dodecafluorodihydrohexane according to claim 1, characterized in that, The fixed-bed reactor in S2 has an inner diameter of 16-24 mm, a length of 800-1000 mm, and is made of stainless steel.

3. The method for catalytic hydrogenation of hexafluoropropylene dimer to synthesize dodecafluorodihydrohexane according to claim 1, characterized in that: The reaction temperature in S2 is 100-300℃, and the reaction pressure is 0.5-5MPa.

4. The method for catalytic hydrogenation of hexafluoropropylene dimer to synthesize dodecafluorodihydrohexane according to claim 1, characterized in that: In S2, the volumetric flow ratio of hexafluoropropylene dimer to hydrogen is 1:1-9, and the space velocity is 45-80 h⁻¹. -1 .

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