A method for preparing a hexafluoropropylene dimer of a coolant liquid for energy storage thermal management

Abstract

The application relates to a preparation method of a hexafluoropropylene dimer of a cooling liquid for energy storage thermal management, and belongs to the technical field of fluorine-containing compound synthesis. Magnesium nitrate and zinc nitrate are dissolved in deionized water, aluminum nitrate is added, ultrasonic dispersion is carried out, and a catalyst is obtained through calcination; the catalyst and a phase transfer catalyst are added into a high-pressure reaction kettle, mixed solvents are added, hexafluoropropylene is introduced, and stirring reaction is carried out; after the reaction is completed, unreacted hexafluoropropylene is slowly released, the catalyst is removed through filtration, the filtrate is washed with water, dried, and distilled to collect a fraction, so that the hexafluoropropylene dimer is obtained; the hexafluoropropylene dimer, an antioxidant and benzotriazole are mixed and stirred to obtain the cooling liquid for energy storage thermal management; the phase transfer catalyst is prepared from (trifluoromethyl) benzene thiol, N, N-diallyl ethanolamine, a free radical initiator, toluene, bromoethane and anhydrous sodium carbonate; the hexafluoropropylene dimer has high purity, high yield and high thermal conductivity, and is suitable for the energy storage thermal management requirement.

Description

Technical Field

[0001] This invention relates to the field of fluorine compound synthesis technology, and in particular to a method for preparing hexafluoropropylene dimer for energy storage thermal management coolant. Background Technology

[0002] With the rapid development of new energy storage technologies, the power density and energy density of energy storage devices such as lithium-ion batteries and flow batteries are constantly increasing. The large amount of heat generated during operation has become a key factor restricting their safe and stable operation. Energy storage thermal management systems achieve rapid heat transfer and dissipation through the circulation of coolant; therefore, the performance of the coolant directly affects the heat dissipation efficiency and service life of the energy storage system.

[0003] Hexafluoropropylene dimer is an important class of fluorinated olefin compounds with excellent chemical stability, high temperature resistance, insulation and good thermal conductivity. The perfluorinated groups in its molecular structure give it extremely low surface tension and good wettability, which can quickly penetrate into the gaps of energy storage devices to achieve efficient and uniform heat dissipation. It is an ideal core component of coolant for energy storage thermal management.

[0004] Chinese Patent CN117504902A: Provides a catalyst and a method for preparing hexafluoropropylene dimer, wherein the hexafluoropropylene dimer undergoes a gas-phase oligomerization reaction in the presence of the catalyst to obtain the hexafluoropropylene dimer.

[0005] Chinese Patent CN119897108A: This patent relates to a catalyst, specifically a catalyst combination for the synthesis of hexafluoropropylene dimers and its preparation method, and a method for synthesizing hexafluoropropylene dimers. The catalyst combination includes: Catalyst A: Support A, selected from at least one of activated alumina and fluorinated alumina; Main catalytic component A, selected from at least one of nickel oxide, magnesium oxide, manganese oxide, and calcium oxide; Co-catalytic component A, selected from at least one of zirconium oxide, praseodymium oxide, neodymium oxide, lanthanum oxide, and cerium oxide; Catalyst B: Support B, selected from at least one of activated carbon and graphite; Main catalytic component B, selected from at least one of cesium fluoride and rubidium fluoride; Co-catalytic component B, selected from at least one of copper fluoride, potassium fluoride, and ferric trifluoride.

[0006] The existing technology has many problems: on the one hand, the catalysts are mostly homogeneous catalysts such as organic amines and metal halides, which can easily cause product pollution after the reaction and generate a large amount of waste liquid, resulting in great environmental pressure; on the other hand, the reaction selectivity is poor, and hexafluoropropylene dimer has multiple isomers, resulting in low content and product yield. Summary of the Invention

[0007] To address the above problems, this invention provides a method for preparing hexafluoropropylene dimer for energy storage thermal management coolants, the steps of which are as follows: Preparation of S1 catalyst: Dissolve 2.8-4.2 parts magnesium nitrate and 1.1-1.9 parts zinc nitrate in 40-50 parts deionized water, add 5-10 parts aluminum nitrate, disperse ultrasonically, stir and evaporate to dryness, dry, and calcine to obtain the catalyst; S2 reaction: Add 1-5 parts of catalyst and 0.05-0.15 parts of phase transfer catalyst to a high-pressure reactor, then add 50-80 parts of mixed solvent. After purging with nitrogen 3-5 times, raise the temperature and introduce 0.9-1.5 parts of hexafluoropropylene for stirring and reaction. S3 Purification: After the reaction is complete, the mixture is cooled to room temperature and unreacted hexafluoropropylene is slowly released. The reaction solution is then filtered to remove the catalyst. The filtrate is washed with water three times, dried with anhydrous sodium sulfate for 2-5 hours, and the fraction is collected by distillation to obtain hexafluoropropylene dimer. Preparation of S4 coolant: Take 60-100 parts of hexafluoropropylene dimer, 0.1-1 parts of antioxidant 1010, and 0.1-0.5 parts of benzotriazole, mix and stir for 15-30 minutes to obtain coolant for energy storage thermal management.

[0008] Preferably, the ultrasonic dispersion time of S1 is 15-30 min.

[0009] Preferably, the evaporation temperature of S1 is 60-80℃.

[0010] Preferably, the drying temperature of S1 is 100-120℃, and the drying time is 4-7h.

[0011] Preferably, the S1 is roasted at a temperature of 300-350℃ for 2-4 hours.

[0012] Preferably, the S2 mixed solvent is a mixture of diethylene glycol dimethyl ether and perfluorohexane in a volume ratio of 1:1.2-1.8.

[0013] Preferably, the S2 stirring reaction temperature is 80-120℃, the reaction pressure is 1.5-3.0MPa, the stirring rate is 300-500r / min, and the reaction time is 2-5h.

[0014] Preferably, the S3 distillation fraction is collected at 0.05 MPa and the fraction at 60-80°C is collected.

[0015] Preferably, the method for preparing the phase transfer catalyst is as follows: H1: According to the mass fractions, add 10-20 parts (trifluoromethyl)benzylthiophenol, 11-18 parts N,N-diallylethanolamine, 0.02-0.03 parts free radical initiator AIBN, and 200-300 parts toluene to a high-pressure reactor equipped with a water separator, stir, and react at 80-90℃ for 1-3 hours; then cool to 70-80℃, turn on the high-pressure system to raise the reactor pressure to 0.3-0.6MPa, and add 12-16 parts bromoethane dropwise at a rate of 0.3-0.7mL / min. When the addition reaches 50%, add 0.2-0.4 parts anhydrous sodium carbonate, and continue stirring to react for 1-3 hours; H2: After the reaction is complete, the reaction solution is cooled to room temperature, the high pressure is released, and the undissolved anhydrous sodium carbonate residue is removed by filtration. The filtrate is transferred to a distillation apparatus to remove toluene from the system by distillation. After distillation, the remaining material is transferred to a vacuum drying oven to dry, and the phase transfer catalyst is obtained.

[0016] Preferably, the vacuum degree of the distillation is 0.08-0.09 MPa and the temperature is 60-70℃.

[0017] Reaction mechanism: Under the action of the free radical initiator AIBN, the mercapto group (-SH) in (trifluoromethyl)thiophenol undergoes homolytic cleavage to generate a mercapto radical. This radical attacks the carbon-carbon double bond of N,N-diallylethanolamine, forming a tertiary amine intermediate containing a trifluoromethylphenyl sulfide structure via a carbon radical intermediate (mercapto-olefin addition reaction). This process is usually carried out in toluene solvent at 80-90°C to reduce side reactions. Subsequently, the lone pair electrons of the nitrogen atom in the tertiary amine intermediate attack the ethyl carbon atom of bromoethane (nucleophilic substitution SN2 mechanism). The nitrogen atom, after combining with the ethyl group, becomes positively charged and reacts with the bromide ion (Br₂). - The reaction forms ion pairs. Adding anhydrous sodium carbonate in the middle of the reaction can neutralize acidic substances and maintain an alkaline environment to promote the reaction. Finally, a trifluoromethyl quaternary ammonium salt with trifluoromethyl, hydroxyl and quaternary ammonium cation groups is obtained.

[0018] Technical effect 1. The reaction steps are highly controllable. First, a tertiary amine skeleton containing trifluoromethyl and thioether bonds is precisely constructed through thiol-olefin addition. Then, quaternary ammonium cations are introduced in a directional manner through quaternization. The two-step reaction conditions are mild and the parameters are easy to control. This can effectively suppress side reactions such as double bond polymerization and multiple substitution, and ensure the structural integrity and purity of the target product.

[0019] 2. The product, trifluoromethyl quaternary ammonium salt, possesses a fluorinated hydrophobic group (-CF3), a hydrophilic hydroxyl group (-OH), and a quaternary ammonium cationic group. Its unique amphiphilic structure enables it to efficiently promote oil-water two-phase reactions in phase transfer catalysis scenarios or play a role in the field of interface regulation, thus expanding the application range of fluorinated quaternary ammonium salts.

[0020] 3. Toluene is used as the solvent in the reaction, and it can be easily removed and recovered by distillation. The added anhydrous sodium carbonate is easily separated by filtration. The overall process generates no difficult-to-treat waste liquid, which is in line with the concept of green synthesis and reduces the environmental protection cost and operation difficulty of industrial production. Attached Figure Description

[0021] Figure 1 The infrared spectrum of the hexafluoropropylene dimer prepared in Example 1 is shown. Detailed Implementation

[0022] To further illustrate the technical means and effects of the present invention in achieving the intended purpose, the following detailed description of the specific implementation methods and effects of the present invention, in conjunction with embodiments, is provided below.

[0023] 1. Purity detection of hexafluoropropylene dimer: Gas chromatography-mass spectrometry was used.

[0024] 2. Hexafluoropropylene dimer yield test: Yield = (actual mass of hexafluoropropylene dimer / theoretical mass of hexafluoropropylene dimer) × 100%.

[0025] 3. Coolant thermal conductivity test: The thermal conductivity was tested using a hot wire thermal conductivity meter at a test temperature of 25℃.

[0026] Example 1 A method for preparing hexafluoropropylene dimer for energy storage thermal management, comprising the following steps: Preparation of S1 catalyst: 2.8 kg magnesium nitrate and 1.1 kg zinc nitrate were dissolved in 40 kg deionized water, 5 kg aluminum nitrate was added, the mixture was ultrasonically dispersed, stirred and evaporated to dryness, dried, and calcined to obtain the catalyst; S2 reaction: 1 kg of catalyst and 0.05 kg of phase transfer catalyst were added to a high-pressure reactor, followed by 50 kg of mixed solvent. After purging with nitrogen three times, the temperature was raised, and 0.9 kg of hexafluoropropylene was introduced for stirring and reaction. S3 Purification: After the reaction is completed, the mixture is cooled to room temperature and unreacted hexafluoropropylene is slowly released. The reaction solution is then filtered to remove the catalyst. The filtrate is washed with water three times, dried with anhydrous sodium sulfate for 2 hours, and the fraction is collected by distillation to obtain hexafluoropropylene dimer. Preparation of S4 coolant: Take 60 kg of hexafluoropropylene dimer, 0.1 kg of antioxidant 1010 and 0.1 kg of benzotriazole, mix and stir for 15 min to obtain coolant for energy storage thermal management.

[0027] The ultrasonic dispersion time of S1 is 15 min.

[0028] The evaporation temperature of S1 is 60℃.

[0029] The drying temperature of S1 is 100℃ and the drying time is 4 hours.

[0030] The S1 is roasted at 300℃ for 2 hours.

[0031] The S2 mixed solvent is a mixture of diethylene glycol dimethyl ether and perfluorohexane in a volume ratio of 1:1.2.

[0032] The S2 stirring reaction temperature is 80℃, the reaction pressure is 1.5MPa, the stirring rate is 300r / min, and the reaction time is 2h.

[0033] The S3 distillation fraction is collected at 0.05 MPa and then at 60°C.

[0034] The method for preparing the phase transfer catalyst is as follows: H1: 10 kg of (trifluoromethyl)thiophenol, 11 kg of N,N-diallylethanolamine, 0.02 kg of free radical initiator AIBN, and 200 kg of toluene were added to a high-pressure reactor equipped with a water separator. The mixture was stirred and reacted at 80°C for 1 h. Subsequently, the temperature was lowered to 70°C, and the high-pressure system was turned on to raise the reactor pressure to 0.3 MPa. 12 kg of bromoethane was added dropwise at a rate of 0.3 mL / min. When the mixture reached 50%, 0.2 kg of anhydrous sodium carbonate was added, and the reaction was continued with stirring for 1 h. H2: After the reaction is complete, the reaction solution is cooled to room temperature, the high pressure is released, and the undissolved anhydrous sodium carbonate residue is removed by filtration. The filtrate is transferred to a distillation apparatus to remove toluene from the system by distillation. After distillation, the remaining material is transferred to a vacuum drying oven to dry, and the phase transfer catalyst is obtained.

[0035] The distillation process is carried out under a vacuum of 0.08 MPa and a temperature of 60°C.

[0036] Example 2 A method for preparing hexafluoropropylene dimer for energy storage thermal management, comprising the following steps: Preparation of S1 catalyst: 3.2 kg magnesium nitrate and 1.3 kg zinc nitrate were dissolved in 44 kg deionized water, 6 kg aluminum nitrate was added, the mixture was ultrasonically dispersed, stirred and evaporated to dryness, dried, and calcined to obtain the catalyst; S2 reaction: 2 kg of catalyst and 0.08 kg of phase transfer catalyst were added to a high-pressure reactor, followed by 60 kg of mixed solvent. After purging with nitrogen four times, the temperature was raised, and 1.1 kg of hexafluoropropylene was introduced for stirring and reaction. S3 Purification: After the reaction is completed, the mixture is cooled to room temperature and unreacted hexafluoropropylene is slowly released. The reaction solution is then filtered to remove the catalyst. The filtrate is washed with water three times, dried with anhydrous sodium sulfate for 3 hours, and the fraction is collected by distillation to obtain hexafluoropropylene dimer. Preparation of S4 coolant: Take 70 kg of hexafluoropropylene dimer, 0.5 kg of antioxidant 1010 and 0.2 kg of benzotriazole, mix and stir for 20 min to obtain coolant for energy storage thermal management.

[0037] The ultrasonic dispersion time of S1 is 20 min.

[0038] The drying temperature of S1 is 65°C.

[0039] The drying temperature of S1 is 105℃ and the drying time is 5h.

[0040] The S1 is roasted at 310℃ for 3 hours.

[0041] The S2 mixed solvent is a mixture of diethylene glycol dimethyl ether and perfluorohexane in a volume ratio of 1:1.4.

[0042] The S2 stirring reaction temperature is 90℃, the reaction pressure is 2MPa, the stirring rate is 400r / min, and the reaction time is 3h.

[0043] The S3 distillation fraction is collected at 0.05 MPa and then at 65°C.

[0044] The method for preparing the phase transfer catalyst is as follows: H1: 14 kg of (trifluoromethyl)benzylthiophenol, 13 kg of N,N-diallylethanolamine, 0.025 kg of free radical initiator AIBN, and 240 kg of toluene were added to a high-pressure reactor equipped with a water separator. The mixture was stirred and reacted at 85°C for 2 h. Subsequently, the temperature was lowered to 75°C, and the high-pressure system was turned on to raise the reactor pressure to 0.4 MPa. 13 kg of bromoethane was added dropwise at a rate of 0.4 mL / min. When the mixture reached 50%, 0.3 kg of anhydrous sodium carbonate was added, and the reaction was continued with stirring for 2 h. H2: After the reaction is complete, the reaction solution is cooled to room temperature, the high pressure is released, and the undissolved anhydrous sodium carbonate residue is removed by filtration. The filtrate is transferred to a distillation apparatus to remove toluene from the system by distillation. After distillation, the remaining material is transferred to a vacuum drying oven to dry, and the phase transfer catalyst is obtained.

[0045] The distillation process is carried out under a vacuum of 0.085 MPa and a temperature of 65°C.

[0046] Example 3 A method for preparing hexafluoropropylene dimer for energy storage thermal management, comprising the following steps: Preparation of S1 catalyst: 4 kg of magnesium nitrate and 1.7 kg of zinc nitrate were dissolved in 48 kg of deionized water, 8 kg of aluminum nitrate was added, the mixture was ultrasonically dispersed, stirred and evaporated to dryness, dried, and calcined to obtain the catalyst; S2 reaction: 4 kg of catalyst and 0.13 kg of phase transfer catalyst were added to a high-pressure reactor, followed by 70 kg of mixed solvent. After purging with nitrogen four times, the temperature was raised, and 1.3 kg of hexafluoropropylene was introduced for stirring and reaction. S3 Purification: After the reaction is completed, the mixture is cooled to room temperature and unreacted hexafluoropropylene is slowly released. The reaction solution is then filtered to remove the catalyst. The filtrate is washed with water three times, dried with anhydrous sodium sulfate for 4 hours, and the fraction is collected by distillation to obtain hexafluoropropylene dimer. Preparation of S4 coolant: Take 90 kg of hexafluoropropylene dimer, 0.8 kg of antioxidant 1010 and 0.4 kg of benzotriazole, mix and stir for 25 min to obtain coolant for energy storage thermal management.

[0047] The ultrasonic dispersion time of S1 is 25 min.

[0048] The drying temperature of S1 is 75°C.

[0049] The drying temperature of S1 is 115℃ and the drying time is 6 hours.

[0050] The S1 is roasted at 340℃ for 3 hours.

[0051] The S2 mixed solvent is a mixture of diethylene glycol dimethyl ether and perfluorohexane in a volume ratio of 1:1.6.

[0052] The S2 stirring reaction temperature is 110℃, the reaction pressure is 2.5MPa, the stirring rate is 400r / min, and the reaction time is 4h.

[0053] The S3 distillation fraction is collected at 0.05 MPa and then at 75°C.

[0054] The method for preparing the phase transfer catalyst is as follows: H1: 18 kg of (trifluoromethyl)benzylthiophenol, 16 kg of N,N-diallylethanolamine, 0.025 kg of free radical initiator AIBN, and 280 kg of toluene were added to a high-pressure reactor equipped with a water separator. The mixture was stirred and reacted at 85°C for 2 h. Subsequently, the temperature was lowered to 75°C, and the high-pressure system was turned on to raise the reactor pressure to 0.5 MPa. 15 kg of bromoethane was added dropwise at a rate of 0.6 mL / min. When the mixture reached 50%, 0.3 kg of anhydrous sodium carbonate was added, and the reaction was continued with stirring for 2 h. H2: After the reaction is complete, the reaction solution is cooled to room temperature, the high pressure is released, and the undissolved anhydrous sodium carbonate residue is removed by filtration. The filtrate is transferred to a distillation apparatus to remove toluene from the system by distillation. After distillation, the remaining material is transferred to a vacuum drying oven to dry, and the phase transfer catalyst is obtained.

[0055] The distillation process is carried out under a vacuum of 0.085 MPa and a temperature of 65°C.

[0056] Example 4 A method for preparing hexafluoropropylene dimer for energy storage thermal management, comprising the following steps: Preparation of S1 catalyst: 4.2 kg magnesium nitrate and 1.9 kg zinc nitrate were dissolved in 50 kg deionized water, 10 kg aluminum nitrate was added, the mixture was ultrasonically dispersed, stirred and evaporated to dryness, dried, and calcined to obtain the catalyst; S2 reaction: 5 kg of catalyst and 0.15 kg of phase transfer catalyst were added to a high-pressure reactor, followed by 80 kg of mixed solvent. After purging with nitrogen five times, the temperature was raised, and 1.5 kg of hexafluoropropylene was introduced for stirring and reaction. S3 Purification: After the reaction is completed, the mixture is cooled to room temperature and unreacted hexafluoropropylene is slowly released. The reaction solution is then filtered to remove the catalyst. The filtrate is washed with water three times, dried with anhydrous sodium sulfate for 5 hours, and the fraction is collected by distillation to obtain hexafluoropropylene dimer. Preparation of S4 coolant: Take 100 kg of hexafluoropropylene dimer, 1 kg of antioxidant 1010 and 0.5 kg of benzotriazole, mix and stir for 30 min to obtain coolant for energy storage thermal management.

[0057] The ultrasonic dispersion time of S1 is 30 min.

[0058] The drying temperature of S1 is 80℃.

[0059] The drying temperature of S1 is 120℃ and the drying time is 7h.

[0060] The S1 is roasted at 350℃ for 4 hours.

[0061] The S2 mixed solvent is a mixture of diethylene glycol dimethyl ether and perfluorohexane in a volume ratio of 1:1.8.

[0062] The S2 stirring reaction temperature is 120℃, the reaction pressure is 3.0MPa, the stirring rate is 500r / min, and the reaction time is 5h.

[0063] The S3 distillation fraction is collected at 0.05 MPa and then at 80°C.

[0064] The method for preparing the phase transfer catalyst is as follows: H1: 20 kg of (trifluoromethyl) thiophenol, 18 kg of N,N-diallylethanolamine, 0.03 kg of free radical initiator AIBN, and 300 kg of toluene were added to a high-pressure reactor equipped with a water separator. The mixture was stirred and reacted at 90°C for 3 h. Subsequently, the temperature was lowered to 80°C, and the high-pressure system was turned on to raise the reactor pressure to 0.6 MPa. 16 kg of bromoethane was added dropwise at a rate of 0.7 mL / min. When the mixture reached 50%, 0.4 kg of anhydrous sodium carbonate was added, and the reaction was continued with stirring for 3 h. H2: After the reaction is complete, the reaction solution is cooled to room temperature, the high pressure is released, and the undissolved anhydrous sodium carbonate residue is removed by filtration. The filtrate is transferred to a distillation apparatus to remove toluene from the system by distillation. After distillation, the remaining material is transferred to a vacuum drying oven to dry, and the phase transfer catalyst is obtained.

[0065] The distillation process is carried out under a vacuum of 0.09 MPa and a temperature of 70°C.

[0066] Comparative Example 1 A method for preparing hexafluoropropylene dimer for energy storage thermal management, comprising the following steps: Preparation of S1 catalyst: 2.8 kg magnesium nitrate and 1.1 kg zinc nitrate were dissolved in 40 kg deionized water, 5 kg aluminum nitrate was added, the mixture was ultrasonically dispersed, stirred and evaporated to dryness, dried, and calcined to obtain the catalyst; S2 reaction: 1 kg of catalyst was added to a high-pressure reactor, followed by 50 kg of mixed solvent. After nitrogen purging three times, the temperature was raised, and 0.9 kg of hexafluoropropylene was introduced for stirring and reaction. S3 Purification: After the reaction is completed, the mixture is cooled to room temperature and unreacted hexafluoropropylene is slowly released. The reaction solution is then filtered to remove the catalyst. The filtrate is washed with water three times, dried with anhydrous sodium sulfate for 2 hours, and the fraction is collected by distillation to obtain hexafluoropropylene dimer. Preparation of S4 coolant: Take 60 kg of hexafluoropropylene dimer, 0.1 kg of antioxidant 1010 and 0.1 kg of benzotriazole, mix and stir for 15 min to obtain coolant for energy storage thermal management.

[0067] The ultrasonic dispersion time of S1 is 15 min.

[0068] The evaporation temperature of S1 is 60℃.

[0069] The drying temperature of S1 is 100℃ and the drying time is 4 hours.

[0070] The S1 is roasted at 300℃ for 2 hours.

[0071] The S2 mixed solvent is a mixture of diethylene glycol dimethyl ether and perfluorohexane in a volume ratio of 1:1.2.

[0072] The S2 stirring reaction temperature is 80℃, the reaction pressure is 1.5MPa, the stirring rate is 300r / min, and the reaction time is 2h.

[0073] The S3 distillation fraction is collected at 0.05 MPa and then at 60°C.

[0074] Comparative Example 2 A method for preparing hexafluoropropylene dimer for energy storage thermal management, comprising the following steps: Preparation of S1 catalyst: 2.8 kg magnesium nitrate and 1.1 kg zinc nitrate were dissolved in 40 kg deionized water, 5 kg aluminum nitrate was added, the mixture was ultrasonically dispersed, stirred and evaporated to dryness, dried, and calcined to obtain the catalyst; S2 reaction: 1 kg of catalyst and 0.05 kg of phase transfer catalyst were added to a high-pressure reactor, followed by 50 kg of mixed solvent. After purging with nitrogen three times, the temperature was raised, and 0.9 kg of hexafluoropropylene was introduced for stirring and reaction. S3 Purification: After the reaction is completed, the mixture is cooled to room temperature and unreacted hexafluoropropylene is slowly released. The reaction solution is then filtered to remove the catalyst. The filtrate is washed with water three times, dried with anhydrous sodium sulfate for 2 hours, and the fraction is collected by distillation to obtain hexafluoropropylene dimer. Preparation of S4 coolant: Take 60 kg of hexafluoropropylene dimer, 0.1 kg of antioxidant 1010 and 0.1 kg of benzotriazole, mix and stir for 15 min to obtain coolant for energy storage thermal management.

[0075] The ultrasonic dispersion time of S1 is 15 min.

[0076] The evaporation temperature of S1 is 60℃.

[0077] The drying temperature of S1 is 100℃ and the drying time is 4 hours.

[0078] The S1 is roasted at 300℃ for 2 hours.

[0079] The S2 mixed solvent is a mixture of diethylene glycol dimethyl ether and perfluorohexane in a volume ratio of 1:1.2.

[0080] The S2 stirring reaction temperature is 80℃, the reaction pressure is 1.5MPa, the stirring rate is 300r / min, and the reaction time is 2h.

[0081] The S3 distillation fraction is collected at 0.05 MPa and then at 60°C.

[0082] The method for preparing the phase transfer catalyst is as follows: H1: 11 kg N,N-diallylethanolamine, 0.02 kg free radical initiator AIBN, and 200 kg toluene were added to a high-pressure reactor equipped with a water separator. The mixture was stirred and reacted at 80°C for 1 h. The temperature was then lowered to 70°C, and the high-pressure system was turned on to raise the reactor pressure to 0.3 MPa. 12 kg bromoethane was added dropwise at a rate of 0.3 mL / min. When the mixture reached 50%, 0.2 kg anhydrous sodium carbonate was added, and the reaction was continued with stirring for 1 h. H2: After the reaction is complete, the reaction solution is cooled to room temperature, the high pressure is released, and the undissolved anhydrous sodium carbonate residue is removed by filtration. The filtrate is transferred to a distillation apparatus to remove toluene from the system by distillation. After distillation, the remaining material is transferred to a vacuum drying oven to dry, and the phase transfer catalyst is obtained.

[0083] The distillation process is carried out under a vacuum of 0.08 MPa and a temperature of 60°C.

[0084] Comparative Example 3 A method for preparing hexafluoropropylene dimer for energy storage thermal management, comprising the following steps: Preparation of S1 catalyst: 2.8 kg magnesium nitrate and 1.1 kg zinc nitrate were dissolved in 40 kg deionized water, 5 kg aluminum nitrate was added, the mixture was ultrasonically dispersed, stirred and evaporated to dryness, dried, and calcined to obtain the catalyst; S2 reaction: 1 kg of catalyst and 0.05 kg of phase transfer catalyst were added to a high-pressure reactor, followed by 50 kg of mixed solvent. After purging with nitrogen three times, the temperature was raised, and 0.9 kg of hexafluoropropylene was introduced for stirring and reaction. S3 Purification: After the reaction is completed, the mixture is cooled to room temperature and unreacted hexafluoropropylene is slowly released. The reaction solution is then filtered to remove the catalyst. The filtrate is washed with water three times, dried with anhydrous sodium sulfate for 2 hours, and the fraction is collected by distillation to obtain hexafluoropropylene dimer. Preparation of S4 coolant: Take 60 kg of hexafluoropropylene dimer, 0.1 kg of antioxidant 1010 and 0.1 kg of benzotriazole, mix and stir for 15 min to obtain coolant for energy storage thermal management.

[0085] The ultrasonic dispersion time of S1 is 15 min.

[0086] The evaporation temperature of S1 is 60℃.

[0087] The drying temperature of S1 is 100℃ and the drying time is 4 hours.

[0088] The S1 is roasted at 300℃ for 2 hours.

[0089] The S2 mixed solvent is a mixture of diethylene glycol dimethyl ether and perfluorohexane in a volume ratio of 1:1.2.

[0090] The S2 stirring reaction temperature is 80℃, the reaction pressure is 1.5MPa, the stirring rate is 300r / min, and the reaction time is 2h.

[0091] The S3 distillation fraction is collected at 0.05 MPa and then at 60°C.

[0092] The method for preparing the phase transfer catalyst is as follows: H1: 10 kg of (trifluoromethyl) thiophenol, 0.02 kg of free radical initiator AIBN, and 200 kg of toluene were added to a high-pressure reactor equipped with a water separator. The mixture was stirred and reacted at 80°C for 1 h. The temperature was then lowered to 70°C, and the high-pressure system was turned on to raise the reactor pressure to 0.3 MPa. 12 kg of bromoethane was added dropwise at a rate of 0.3 mL / min. When the mixture reached 50%, 0.2 kg of anhydrous sodium carbonate was added, and the reaction was continued with stirring for 1 h. H2: After the reaction is complete, the reaction solution is cooled to room temperature, the high pressure is released, and the undissolved anhydrous sodium carbonate residue is removed by filtration. The filtrate is transferred to a distillation apparatus to remove toluene from the system by distillation. After distillation, the remaining material is transferred to a vacuum drying oven to dry, and the phase transfer catalyst is obtained.

[0093] The distillation process is carried out under a vacuum of 0.08 MPa and a temperature of 60°C.

[0094] Table 1. Results of purity, yield, and thermal conductivity of hexafluoropropylene dimer in the examples and comparative schemes.

[0095] A phase-transfer catalyst successfully achieved the directed conversion of (trifluoromethyl)benzylthiophenol and N,N-diallylethanolamine via a two-step process of "thiol-olefin addition-quaternization." This not only solves the problems of difficult product structure control and numerous side reactions in the synthesis of fluorinated quaternary ammonium salts, but also endows the product with unique properties through the synergistic retention of functional groups, making it particularly suitable for the preparation of high-performance phase-transfer catalysts. From a process perspective, the reaction conditions are mild, the post-processing is simple, and it is environmentally friendly, ensuring both product quality and yield, and providing a feasible route for industrial-scale production. It has significant technical advantages and application value in the field of fluorinated functional compound synthesis.

[0096] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for preparing hexafluoropropylene dimer of a coolant for energy storage thermal management, comprising the following steps, in parts by mass: Preparation of S1 catalyst: Dissolve 2.8-4.2 parts magnesium nitrate and 1.1-1.9 parts zinc nitrate in 40-50 parts deionized water, add 5-10 parts aluminum nitrate, disperse ultrasonically, stir and evaporate to dryness, dry, and calcine to obtain the catalyst; S2 reaction: Add 1-5 parts of catalyst and 0.05-0.15 parts of phase transfer catalyst to a high-pressure reactor, then add 50-80 parts of mixed solvent. After purging with nitrogen 3-5 times, raise the temperature and introduce 0.9-1.5 parts of hexafluoropropylene for stirring and reaction. S3 Purification: After the reaction is complete, the mixture is cooled to room temperature and unreacted hexafluoropropylene is slowly released. The reaction solution is then filtered to remove the catalyst. The filtrate is washed with water three times, dried with anhydrous sodium sulfate for 2-5 hours, and the fraction is collected by distillation to obtain hexafluoropropylene dimer. Preparation of S4 coolant: Take 60-100 parts of hexafluoropropylene dimer, 0.1-1 parts of antioxidant 1010, and 0.1-0.5 parts of benzotriazole, mix and stir for 15-30 minutes to obtain coolant for energy storage thermal management; The phase transfer catalyst is prepared by reacting (trifluoromethyl)benzylthiophenol, N,N-diallylethanolamine, free radical initiator AIBN, and anhydrous sodium carbonate.

2. The method for preparing hexafluoropropylene dimer of a coolant for energy storage thermal management according to claim 1, characterized in that: The ultrasonic dispersion time of S1 is 15-30 min.

3. The method for preparing hexafluoropropylene dimer of a coolant for energy storage thermal management according to claim 1, characterized in that: The temperature at which S1 is evaporated is 60-80℃.

4. The method for preparing hexafluoropropylene dimer of a coolant for energy storage thermal management according to claim 1, characterized in that: The drying temperature of S1 is 100-120℃, and the drying time is 4-7h.

5. The method for preparing hexafluoropropylene dimer of a coolant for energy storage thermal management according to claim 1, characterized in that: The S1 is calcined at a temperature of 300-350℃ for 2-4 hours.

6. The method for preparing hexafluoropropylene dimer of a coolant for energy storage thermal management according to claim 1, characterized in that: The S2 mixed solvent is a mixture of diethylene glycol dimethyl ether and perfluorohexane in a volume ratio of 1:1.2-1.

8.

7. The method for preparing hexafluoropropylene dimer of a coolant for energy storage thermal management according to claim 1, characterized in that: The S2 stirring reaction temperature is 80-120℃, the reaction pressure is 1.5-3.0MPa, the stirring rate is 300-500r / min, and the reaction time is 2-5h.

8. The method for preparing hexafluoropropylene dimer of a coolant for energy storage thermal management according to claim 1, characterized in that: The S3 distillation fraction is collected at 0.05 MPa and the fraction at 60-80℃ is collected.

9. The method for preparing hexafluoropropylene dimer of a coolant for energy storage thermal management according to claim 1, characterized in that: The method for preparing the phase transfer catalyst is as follows: H1: According to the mass fractions, add 10-20 parts (trifluoromethyl)benzylthiophenol, 11-18 parts N,N-diallylethanolamine, 0.02-0.03 parts free radical initiator AIBN, and 200-300 parts toluene to a high-pressure reactor equipped with a water separator, stir, and react at 80-90℃ for 1-3 hours; then cool to 70-80℃, turn on the high-pressure system to raise the reactor pressure to 0.3-0.6MPa, and add 12-16 parts bromoethane dropwise at a rate of 0.3-0.7mL / min. When the addition reaches 50%, add 0.2-0.4 parts anhydrous sodium carbonate, and continue stirring to react for 1-3 hours; H2: After the reaction is complete, the reaction solution is cooled to room temperature, the high pressure is released, and the undissolved anhydrous sodium carbonate residue is removed by filtration. The filtrate is transferred to a distillation apparatus to remove toluene from the system by distillation. After distillation, the remaining material is transferred to a vacuum drying oven to dry, and the phase transfer catalyst is obtained.

10. The method for preparing hexafluoropropylene dimer of a coolant for energy storage thermal management according to claim 9, characterized in that: The distillation process is carried out under a vacuum of 0.08-0.09 MPa and a temperature of 60-70℃.

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