A process and apparatus for the preparation of tetrafluoroethane-beta-sultone

Abstract

This invention belongs to the field of chemical synthesis technology, specifically relating to a method and apparatus for preparing tetrafluoroethane-β-sulfonyl lactone. The method for preparing tetrafluoroethane-β-sulfonyl lactone according to this invention includes the following steps: Under a Lewis base catalysis system, difluoroacetyl fluoride and fluorochlorosulfonyl undergo a nucleophilic substitution reaction in an organic solvent. During the reaction, hydrogen chloride is removed under temperature and negative pressure to shift the reaction equilibrium towards the product, yielding the intermediate 2-(fluorosulfonyl)difluoroacetyl fluoride; under a Lewis acid catalysis system, the intermediate obtained in step one undergoes an intramolecular ring-closure reaction in an organic solvent. After the reaction, the intermediate is collected by distillation to obtain tetrafluoroethane-β-sulfonyl lactone. The method for preparing tetrafluoroethane-β-sulfonyl lactone provided by this invention features mild reaction conditions, high raw material conversion rate, safety and controllability, and reduced operating costs. This invention also provides a preparation apparatus.

Description

Technical Field

[0001] This invention belongs to the field of chemical synthesis technology, specifically relating to a method and apparatus for preparing tetrafluoroethane-β-sulfonolactone. Background Technology

[0002] Tetrafluoroethane-β-sulfonyl lactone (TFESL) is a core intermediate in the field of fluorinated fine chemicals. Its molecular structure combines a highly reactive four-membered β-sulfonyl lactone ring with a chemically stable perfluoroalkyl chain: the four-membered sulfonyl lactone ring endows the molecule with excellent electrophilic reactivity, allowing for the efficient introduction of perfluoroalkyl sulfonic acid structures through ring-opening, addition, and substitution reactions; while the perfluoroalkyl chain significantly enhances the chemical stability and electrochemical performance of the products. Based on this unique structural characteristic, TFESL can be used as a starting point to derive a series of high-value-added products, including perfluoroalkyl sulfonic acids, perfluorosulfonyl fluorides, fluorosulfonic acid resins, functional additives for lithium battery electrolytes, fluorinated surfactants, and pharmaceutical intermediates. These derivatives have irreplaceable application value in strategic emerging industries such as new energy, electronic chemicals, high-end materials, and pharmaceuticals and pesticides, making TFESL a key raw material supporting the upgrading of my country's fluorochemical industry towards high-end and refined production. With the rapid development of downstream industries such as new energy vehicles, semiconductors, and information communication, the market demand for TFESL is showing a sustained and rapid growth trend.

[0003] Currently, the mainstream industrial synthesis process for tetrafluoroethane-β-sulfonyl lactone is the [2+2] cycloaddition reaction of tetrafluoroethylene (TFE) and sulfur trioxide (SO3). However, this process mainly suffers from high safety risks, poor reaction selectivity, and low yield. Tetrafluoroethylene (TFE) is a hazardous chemical, and sulfur trioxide is a highly corrosive, strongly oxidizing, and fuming chemical, thus posing significant safety hazards. Furthermore, the aforementioned [2+2] cycloaddition reaction is a strongly exothermic reaction, making it difficult to precisely control reaction conditions. This can easily lead to various side reactions, such as the self-polymerization of tetrafluoroethylene to form polytetrafluoroethylene oligomers, the polymerization of sulfur trioxide to form pyrosulfuric acid, and excessive addition to form polysulfonation byproducts, further increasing production costs.

[0004] CN114950320A discloses a method for the continuous synthesis of tetrafluoroethane-β-sulfonyl lactone. This method simplifies the synthesis process by using a batch-type continuous reactor, which improves the safety of the reactor operation to a certain extent, and also features high reaction efficiency and few by-products. However, this method still directly uses tetrafluoroethylene and sulfur trioxide as raw materials, and the reaction pressure needs to be controlled at 0.1~0.5 MPa. Under these conditions, the risk of tetrafluoroethylene self-polymerization remains significant, and the gas-liquid heterogeneous reaction is prone to local overheating, making it difficult to suppress side reactions.

[0005] CN117304165A discloses a continuous preparation method and apparatus for tetrafluoroethane-β-sulfonyl lactone. By intermittently introducing tetrafluoroethylene, the pressure inside the reactor is maintained within a suitable range, and the reaction rate is controlled, thereby improving the safety of the reaction process. Thorough mixing of the gas and liquid phases is utilized to improve reaction efficiency. However, this method still does not overcome the problems associated with using sulfur trioxide and tetrafluoroethylene as raw materials. Summary of the Invention

[0006] The technical problem this invention aims to solve is to overcome the existing technical problems such as high safety risks, harsh reaction conditions, numerous side reactions, low yields, and difficulties in separation and purification. This invention provides a method for preparing tetrafluoroethane-β-sulfonolactone with mild reaction conditions, high raw material conversion rate, safety and controllability, and reduced operating costs. This invention also provides a preparation apparatus.

[0007] The preparation method of tetrafluoroethane-β-sulfonyl lactone according to the present invention includes the following steps: Step 1, nucleophilic substitution reaction: Under the action of Lewis base catalysis, difluoroacetyl fluoride and fluorochlorosulfonyl undergo a nucleophilic substitution reaction in an organic solvent. During the reaction, the generated hydrogen chloride is removed under the drive of temperature and negative pressure to shift the reaction equilibrium toward the product, yielding the intermediate 2-(fluorosulfonyl)difluoroacetyl fluoride. Step 2, Intramolecular Ring-Closing Reaction: Under the catalysis of a Lewis acid, the intermediate obtained in Step 1 undergoes an intramolecular ring-closing reaction in an organic solvent. After the reaction, the target fraction is collected by distillation to obtain tetrafluoroethane-β-sulfonolactone. The main fraction is collected by distillation, and the purity of the obtained tetrafluoroethane-β-sulfonolactone is greater than 99.8%; the yield is greater than 94%.

[0008] The reaction process is as follows: .

[0009] This invention is the first to use difluoroacetyl fluoride and fluorochlorosulfonyl as raw materials, and through the construction of carbon-sulfur bonds and subsequent intramolecular cyclization, it ingeniously replaces the traditional, highly hazardous direct cycloaddition route of tetrafluoroethylene and sulfur trioxide. This route avoids the direct use of high-pressure gases and highly corrosive / oxidizing raw materials, and the reaction is carried out under normal pressure or slightly negative pressure and medium-low temperature conditions, making the process safe and controllable.

[0010] Furthermore, in step one, the molar ratio of difluoroacetyl fluoride to fluorochlorosulfonyl is 1.1~1.3:1. Preferably, difluoroacetyl fluoride is added in slight excess to ensure complete reaction of the more expensive or relatively toxic fluorochlorosulfonyl, while the excess portion is easily separated subsequently.

[0011] Furthermore, in step one, the Lewis base catalytic system consists of tri-tert-butylphosphine, tetrabutylphosphine chloride, and anhydrous KF, with a molar ratio of tri-tert-butylphosphine, tetrabutylphosphine chloride, and anhydrous KF of 1:0.3~0.5:0.5~0.8. Tri-tert-butylphosphine, as a bulky electron-rich phosphine ligand, effectively activates the acyl fluoride group of difluoroacetyl fluoride; tetrabutylphosphine chloride acts as a phase transfer catalyst and ion pair stabilizer, promoting the mixing and contact of reactants in the organic phase; and anhydrous KF acts as a fluoride ion donor, assists in deacidification, and promotes phosphine base regeneration, synergistically promoting the nucleophilic substitution reaction.

[0012] Furthermore, the molar ratio of tri-tert-butylphosphine to fluorochlorosulfonyl is 0.03~0.05:1. This specific combination of catalysts exhibits extremely high selectivity for the target reaction and can effectively suppress side reactions.

[0013] Furthermore, in step one, the organic solvent is trifluorotoluene or cyclohexane; trifluorotoluene has excellent solubility and stable chemical properties, while cyclohexane is lower in cost and easier to recover. The reaction temperature is 35~45℃ (controlled in the reactor); to achieve better process control and conversion rate, the reaction can be carried out in a continuous reaction device, with the temperatures of the materials in the primary, secondary, and tertiary reactors controlled at 30~40℃, 25~35℃, and 30~40℃ respectively, forming a gradient temperature control, which is beneficial for stable reaction and control of exothermic reactions. The reaction system is maintained under a slight negative pressure (-0.09~-0.099MPa) to remove HCl gas in a timely manner. Subsequently, the circulation pump is turned on, with a circulation flow rate of 3~5kg / h, to achieve thorough mixing and heat transfer of the reaction mixture.

[0014] Furthermore, the feeding rate of difluoroacetyl fluoride is 0.455~1.075 kg / h, and the feeding rate of fluorochlorosulfonyl is 0.5~1 kg / h. This feeding rate is matched with the reactor volume and residence time to ensure a complete reaction.

[0015] Furthermore, in step two, the Lewis acid catalytic system consists of tris(pentafluorophenyl)borane, a boron trifluoride acetonitrile complex, and perfluorobutylsulfonyl fluoride, with a molar ratio of tris(pentafluorophenyl)borane, the boron trifluoride acetonitrile complex, and perfluorobutylsulfonyl fluoride of 1:0.2~0.5:0.1~0.3. Tris(pentafluorophenyl)borane is a strong Lewis acid that can effectively activate the carbonyl oxygen in the intermediate (FSO2-CF2-COF), promoting fluorine atom migration and cyclization; the boron trifluoride acetonitrile complex acts as a co-catalyst, stabilizing the reaction transition state; and the perfluorobutylsulfonyl fluoride improves the solubility of the system and inhibits possible polymerization side reactions.

[0016] Furthermore, the molar ratio of tris(pentafluorophenyl)borane to fluorochlorosulfonyl in step one is 0.01~0.03:1.

[0017] Furthermore, in step two, the organic solvent is trifluorotoluene or cyclohexane; the ring-closing reaction is carried out in a cyclization reactor at a temperature of 10-20°C. The lower temperature is conducive to the stable formation of the four-membered ring structure and prevents ring-opening or polymerization. A condenser is installed at the top of the cyclization reactor, with a temperature of 8-18°C, to condense and reflux the low-boiling-point components and simultaneously discharge any non-condensable gases that may be generated.

[0018] Furthermore, to ensure reaction yield and purity, the purity of the difluoroacetyl fluoride and fluorochlorosulfonyl must be greater than 99%, and the water content must be less than 50 ppm. Strictly limiting moisture content prevents hydrolysis of the raw materials and deactivation of the catalytic system.

[0019] The apparatus for preparing tetrafluoroethane-β-sulfonyl lactone includes a premixer, the outlet of which is sequentially connected to a primary reactor, a secondary reactor, and a tertiary reactor; the outlet of the tertiary reactor is connected to a reaction vessel, and the reaction vessel returns to the inlet of the premixer through a circulating pump pipeline, forming a circulation loop; a packed tower a is installed at the top of the reaction vessel to separate and export the product gases (mainly intermediates and HCl) of a series of reactions; the outlet of packed tower a is connected to a cyclization vessel; a packed tower b and a condenser are installed at the top of the cyclization vessel; a fluorochlorosulfonyl metering pump is connected to the premixer; the premixer is connected to a fluorochlorosulfonyl storage tank and a difluoroacetyl fluoride storage tank, respectively.

[0020] The primary, secondary, and tertiary reactors are all tubular or series-connected reactors, with tubular reactors preferred for continuous operation and heat transfer. Both the reaction vessel and the cyclization vessel are equipped with jacketed heating / cooling devices for precise temperature control.

[0021] The system also includes a gas treatment and recovery device connected to the non-condensable gas outlet of the condenser for treating exhaust gas.

[0022] The workflow of this device is as follows: raw materials are initially mixed in a premixer, and then undergo deep reaction in a three-stage reactor. The reaction liquid enters the reaction vessel, and part of it is returned to the premixer via a circulating pump to control the reaction intensity and concentration. The gaseous phase generated by the reaction (containing intermediates, HCl, etc.) enters the cyclization vessel through packed tower a, where cyclization is completed at low temperature. The product is collected at the bottom of the cyclization vessel, and the tail gas is condensed and refluxed by a condenser. The non-condensable gas enters the tail gas treatment system.

[0023] The recirculation loop designed in the device of this invention allows for full utilization of the catalyst and unreacted materials, reducing consumption. Simultaneously, the Lewis acid catalytic system in step two enables efficient recovery and recycling (tris(pentafluorophenyl)borane, etc., can be reused after simple treatment), significantly reducing catalytic costs. Furthermore, the solvents used (trifluorotoluene or cyclohexane) can be recovered and reused through simple distillation, effectively reducing the discharge of organic waste liquid and aligning with the development trend of green chemistry. In summary, this invention not only solves the safety and cost bottlenecks of traditional processes but also demonstrates comprehensive advantages in product quality, raw material utilization, environmental friendliness, and industrial feasibility, possessing significant economic benefits and social value.

[0024] Specifically, the preparation method of tetrafluoroethane-β-sulfolactone according to the present invention includes the following steps: First, add trifluorotoluene or cyclohexane to the reactor. Then, slowly add tri-tert-butylphosphine, tetrabutylphosphine chloride, and anhydrous KF at 35-45°C. Next, add trifluorotoluene or cyclohexane to the cyclization reactor. Then, slowly add tris(pentafluorophenyl)borane, boron trifluoride acetonitrile complex, and perfluorobutylsulfonyl fluoride at 10-20°C. Then, set the temperatures of the primary, secondary, and tertiary reactors to 30-40°C, 25-35°C, and 30-40°C, respectively, with the condenser temperature at 8-15°C. Maintain a slight negative pressure (approximately -0.095 MPa) in the system. Finally, start the circulation pump at a flow rate of 3-5 kg / h. After stabilization, difluoroacetyl fluoride and fluorochlorosulfonyl are added at 0.455~1.075 kg / h and 0.5~1 kg / h respectively. The reaction vessel is kept at a temperature of 35~45℃ for continuous reaction. During the reaction, the reaction mixture enters the cyclization system intermediate, which is condensed and liquefied before entering the cyclization vessel (other low-boiling-point and non-condensable vapors enter the gas treatment and recovery device). The cyclization reaction is completed at 10~20℃ to obtain the organic phase. The final product, tetrafluoroethane-β-sulfonyl lactone, is obtained by distillation.

[0025] This invention employs a segmented continuous reaction design. Step one utilizes a ternary Lewis base catalytic system of "tri-tert-butylphosphine / tetrabutylphosphine chloride / anhydrous KF," which significantly improves the conversion rate and selectivity of the nucleophilic substitution reaction through synergistic catalysis and timely removal of HCl. Step two employs a ternary Lewis acid catalytic system of "tris(pentafluorophenyl)borane / boron trifluoride acetonitrile complex / perfluorobutylsulfonyl fluoride," which efficiently promotes intramolecular ring closure at low temperatures and effectively suppresses side reactions such as ring-opening polymerization. Through the above precise control, the overall yield of this invention, based on fluorochlorosulfonyl, can reach over 90%, and the purity of the product after distillation exceeds 99.8%. In contrast, when using a single catalyst or a non-recycling process in the comparative example, the yield significantly decreases to 55%~81.5%, and the purity is also significantly reduced.

[0026] Compared with the prior art, the beneficial effects of the present invention are: (1) This invention abandons the traditional process of directly using flammable, explosive, and easily self-polymerizing tetrafluoroethylene (TFE) and highly corrosive and oxidizing sulfur trioxide as raw materials, and innovatively uses relatively stable and widely available industrial difluoroacetyl fluoride and fluorochlorosulfonyl as starting materials. The entire reaction process is carried out under slightly negative pressure and medium-low temperature (10~45℃) conditions, without the need for high-pressure operation, thus eliminating the safety risks caused by raw material self-polymerization, strong exothermic runaway, and equipment leakage from the source.

[0027] (2) This invention creatively adopts a segmented continuous reaction design, independently controlling the two key steps of nucleophilic substitution and intramolecular ring closure in stages, thus avoiding interference from side reactions in the traditional one-pot or direct cycloaddition methods. At the same time, highly efficient composite catalytic systems have been developed for each step based on its reaction characteristics.

[0028] (3) The present invention provides a dedicated continuous production device (including a premixer, a multi-stage series reactor, a circulation loop and a cyclic reactor, etc.) that is highly compatible with the method, which can achieve long-term stable continuous operation, with minimal scale-up effect and easy industrial promotion. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the apparatus for preparing tetrafluoroethane-β-sulfonolactone according to the present invention.

[0030] Figure 2 The gas chromatogram is for tetrafluoroethane-β-sulcinolone standard.

[0031] Figure 3 The image shows a gas chromatogram of the tetrafluoroethane-β-sulfonyl lactone sample prepared in Example 1.

[0032] Figure 1 In the middle: 1. Fluorochlorosulfonyl storage tank; 2. Fluorochlorosulfonyl metering pump; 3. Difluoroacetyl fluoride storage tank; 4. Difluoroacetyl fluoride metering pump; 5. Premixer; 6. Primary reactor; 7. Secondary reactor; 8. Tertiary reactor; 9. Reactor; 10. Circulation pump; 11. Packed tower a; 12. Circulation vessel; 13. Packed tower b; 14. Condenser. Detailed Implementation

[0033] The present invention will be further described below with reference to specific embodiments.

[0034] The preparation apparatus of the present invention, such as Figure 1As shown, the apparatus for preparing tetrafluoroethane-β-sulfonyl lactone includes a premixer 5. The outlet of the premixer 5 is sequentially connected to a primary reactor 6, a secondary reactor 7, and a tertiary reactor 8. The outlet of the tertiary reactor 8 is connected to a reaction vessel 9. The reaction vessel 9 returns to the inlet of the premixer 5 through a circulation pump 10, forming a circulation loop. A packed tower a11 is installed at the top of the reaction vessel 9 to separate and export the product gases of a series of reactions, mainly intermediates and HCl. The outlet of the packed tower a11 is connected to a cyclization vessel 12. A packed tower b13 and a condenser 14 are installed at the top of the cyclization vessel 12. A fluorochlorosulfonyl metering pump 2 is connected to the premixer 5. The premixer 5 is connected to a fluorochlorosulfonyl storage tank 1 and a difluoroacetyl fluoride storage tank 3. The fluorochlorosulfonyl storage tank 1 is connected to the premixer 5 through the fluorochlorosulfonyl metering pump 2. The difluoroacetyl fluoride storage tank 3 is connected to the premixer 5 through the difluoroacetyl fluoride metering pump 4. The material outlet of premixer 5 is sequentially connected to primary reactor 6, secondary reactor 7, and tertiary reactor 8. The top material outlet of tertiary reactor 8 is connected to packed tower a11. The bottom material of packed tower a11 enters reactor 9, while the top gaseous material enters the pipeline connecting packed tower b13 and circulator 12. The condensed liquid phase enters circulator 12, and the uncondensed gaseous phase enters packed tower b13. The gaseous outlet of packed tower b13 is connected to the non-condensable gas outlet of condenser 14 for tail gas treatment. It is also connected to a gas treatment and recovery device. A pipeline is also installed inside reactor 9 connecting to the material inlet of premixer 5, and a circulation pump 10 is installed on this pipeline.

[0035] The primary reactor 6, secondary reactor 7, and tertiary reactor 8 are all tubular reactors or series-connected batch reactors, with tubular reactors preferred to facilitate continuous operation and heat transfer. Both the reaction vessel 9 and the cyclization vessel 12 are equipped with jacketed heating / cooling devices for precise temperature control.

[0036] Example 1 The preparation method of tetrafluoroethane-β-sulfonyl lactone according to the present invention includes the following steps: First, 5.01 kg of trifluorotoluene was added to reactor 9. Then, 74.19 g of tri-tert-butylphosphine, 43.25 g of tetrabutylphosphine chloride, and 13.84 g of anhydrous KF were slowly added at 37°C. Next, 5.03 kg of trifluorotoluene was added to cyclization reactor 12. Then, 91.58 g of tris(pentafluorophenyl)borane, 6.81 g of boron trifluoride acetonitrile complex, and 10.8 g of perfluorobutylsulfonyl fluoride were slowly added at 15°C. The temperatures of primary reactor 6, secondary reactor 7, and tertiary reactor 8 were set to 35°C, 30°C, and 35°C, respectively, with condenser 14 at 12°C. The system was maintained under a slight negative pressure (-0.095 MPa). Then, circulation pump 10 was started at a flow rate of 4 kg / h. After stabilization, difluoroacetyl fluoride and... Fluorochlorosulfonyl was added at 0.857 kg / h and 0.85 kg / h respectively (a total of 1.069 kg of difluoroacetyl fluoride and 1.06 kg of fluorochlorosulfonyl were added). The reaction was carried out continuously at 37°C in the reactor. During the reaction, the reaction mixture entered the cyclization system intermediate, which was condensed and liquefied before entering the cyclization reactor 12. The cyclization reaction was completed at 15°C to obtain the organic phase. Distillation yielded 1.54 kg of the final product, tetrafluoroethane-β-sulfonyl lactone, with a yield of 95.52% and a purity of 99.9%. The gas chromatogram of the prepared tetrafluoroethane-β-sulfonyl lactone is shown below. Figure 3 As shown, Figure 2 The gas chromatograms of tetrafluoroethane-β-sulfonyl lactone standards show that the retention time of the product prepared by this invention is completely matched with that of the standard, and the peak shape and impurity situation are highly consistent with those of the standard. This proves that the preparation method successfully synthesized the target product, and the product has high purity and no obvious impurity interference.

[0037] Example 2 The preparation method of tetrafluoroethane-β-sulfonyl lactone according to the present invention includes the following steps: First, add 5.02 kg of trifluorotoluene to reactor 9. Then, slowly add 53.77 g of tri-tert-butylphosphine, 27.43 g of tetrabutylphosphine chloride, and 12.35 g of anhydrous KF at 40°C. Next, add 5.01 kg of trifluorotoluene to cyclization reactor 12. Then, slowly add 68.04 g of tris(pentafluorophenyl)borane, 7.23 g of boron trifluoride acetonitrile complex, and 6.02 g of perfluorobutylsulfonyl fluoride at 10°C. Then, set the temperatures of primary reactor 6, secondary reactor 7, and tertiary reactor 8 to 35°C, 30°C, and 35°C respectively, and the temperature of condenser 14 to 10°C. Maintain a slight negative pressure (-0.095 MPa) in the system. Then, start the circulation pump 10 at a flow rate of 3 kg / h. After stabilization, add difluoroacetyl fluoride and... Fluorochlorosulfonyl was added at 0.455 kg / h and 0.5 kg / h respectively (a total of 0.955 kg of difluoroacetyl fluoride and 1.05 kg of fluorochlorosulfonyl were added). The reaction was carried out continuously in the reactor at a controlled temperature of 40°C. During the reaction, the reaction mixture entered the cyclization system intermediate, which was condensed and liquefied before entering the cyclization reactor 12. The cyclization reaction was completed at 10°C to obtain the organic phase. The final product, tetrafluoroethane-β-sulfonyl lactone, was obtained by distillation at 1.507 kg. The yield was calculated to be 94.31%, and the purity was determined to be 99.82%.

[0038] Example 3 The preparation method of tetrafluoroethane-β-sulfonyl lactone according to the present invention includes the following steps: First, 5.03 kg of cyclohexane was added to reactor 9. Then, 63.03 g of tri-tert-butylphosphine, 27.56 g of tetrabutylphosphine chloride, and 9.05 g of anhydrous KF were slowly added at 35°C. Next, 5.01 kg of cyclohexane was added to cyclization reactor 12. Then, 45.57 g of tris(pentafluorophenyl)borane, 1.93 g of boron trifluoride acetonitrile complex, and 2.69 g of perfluorobutylsulfonyl fluoride were slowly added at 12°C. The temperatures of primary reactor 6, secondary reactor 7, and tertiary reactor 8 were set to 30°C, 25°C, and 30°C, respectively, with condenser 14 at 15°C. The system was maintained under a slight negative pressure (-0.095 MPa). Then, circulation pump 10 was started at a flow rate of 3 kg / h. After stabilization, difluoroacetyl fluoride and... Fluorochlorosulfonyl was added at 0.665 kg / h and 0.7 kg / h respectively (totaling 1.003 kg of difluoroacetyl fluoride and 1.055 kg of fluorochlorosulfonyl), and the reaction was carried out continuously in the reactor at a controlled temperature of 35°C. During the reaction, the reaction mixture entered the cyclization system intermediate, which was condensed and liquefied before entering the cyclization reactor 12. The cyclization reaction was completed at 12°C to obtain an organic phase. The final product, tetrafluoroethane-β-sulfonyl lactone, was obtained by distillation, with a yield of 93.47% and a purity of 99.86%.

[0039] Example 4 The preparation method of tetrafluoroethane-β-sulfonyl lactone according to the present invention includes the following steps: First, 5.04 kg of cyclohexane was added to reactor 9. Then, 89.79 g of tri-tert-butylphosphine, 65.43 g of tetrabutylphosphine chloride, and 15.47 g of anhydrous KF were slowly added at 45°C. Next, 5.02 kg of cyclohexane was added to cyclization reactor 12. Then, 136.33 g of tris(pentafluorophenyl)borane, 8.69 g of boron trifluoride acetonitrile complex, and 24.13 g of perfluorobutylsulfonyl fluoride were slowly added at 20°C. The temperatures of primary reactor 6, secondary reactor 7, and tertiary reactor 8 were set to 40°C, 35°C, and 40°C, respectively. The temperature of condenser 14 was 8°C, and the system was maintained at a slight negative pressure (-0.095 MPa). Then, circulation pump 10 was started at a flow rate of 4 kg / h. After stabilization, difluoroacetyl fluoride and... Fluorochlorosulfonyl was added at 1.075 kg / h and 1 kg / h respectively (a total of 1.131 kg of difluoroacetyl fluoride and 1.052 kg of fluorochlorosulfonyl were added). The reaction was carried out continuously in the reactor at a controlled temperature of 45°C. During the reaction, the reaction mixture entered the cyclization system intermediate, which was condensed and liquefied before entering the cyclization reactor 12. The cyclization reaction was completed at 20°C to obtain the organic phase. The final product, tetrafluoroethane-β-sulfonyl lactone, was obtained by distillation, with a yield of 92.77% and a purity of 99.87%.

[0040] Comparative Example 1 The method and apparatus were basically the same as in Example 1, except that tetrabutylphosphine chloride and anhydrous KF were omitted in step one, and only an equimolar amount of tri-tert-butylphosphine (74.19 g; 0.366 mol) was used as the catalyst.

[0041] Results: The reaction conversion rate decreased significantly. After 8 hours of reaction, only 0.947 kg of product was collected, with a yield of 55% and a product purity of 93.5%.

[0042] Comparative Example 2 The method and apparatus were basically the same as in Example 1, except that anhydrous KF was omitted in step one, and only equimolar amounts of tri-tert-butylphosphine (74.19 g; 0.366 mol) and tetrabutylphosphine chloride (43.25 g; 0.146 mol) were used as catalysts.

[0043] Results: The reaction conversion rate decreased significantly. After 8 hours of reaction, only 1.176 kg of product was collected, with a yield of 69% and a product purity of 94.5%.

[0044] Comparative Example 3 The method and apparatus were basically the same as in Example 1, except that in step two, tris(pentafluorophenyl)borane and perfluorobutylsulfonyl fluoride were omitted, and only an equimolar amount of boron trifluoride acetonitrile complex (6.81 g; 0.062 mol) was used as the catalyst.

[0045] Results: The closed-loop reaction was incomplete, and partial decomposition occurred. After 8 hours of reaction, 0.874 kg of product was collected, with a yield of 50.2% and a product purity of 92.5%.

[0046] Comparative Example 4 The method and apparatus were basically the same as those in Example 1, except that in step two, tris(pentafluorophenyl)borane was omitted, and only equimolar amounts of boron trifluoride acetonitrile complex (6.81 g; 0.062 mol) and perfluorobutyl sulfonyl fluoride were used as catalysts.

[0047] Results: The closed-loop reaction was incomplete, and partial decomposition occurred. After 8 hours of reaction, 1.141 kg of product was collected, with a yield of 67.8% and a product purity of 95.7%.

[0048] Comparative Example 5 The same raw materials, catalyst system, solvent, and apparatus flow as in Example 1 are used, with the difference being that the series configuration of primary reactor 6, secondary reactor 7, and tertiary reactor 8 is eliminated, and replaced with a single-stage tubular reactor (with a volume equivalent to the total volume of the three-stage reactor). This reactor uses jacketed constant-temperature heating, with the temperature controlled at 35°C. Other conditions remain unchanged: the outlet of premixer 5 is directly connected to this single-stage reactor, and the outlet of the single-stage reactor is then connected to reactor 9. The circulation loop and other configurations remain unchanged.

[0049] Specific operations: According to the proportions in Example 1, solvent and catalyst were added to reaction vessel 9 and cyclization vessel 12.

[0050] The temperature of the single-stage tubular reactor was kept constant at 35℃, the system was under a slight negative pressure of -0.095MPa, and the circulation flow rate was 4kg / h.

[0051] The raw materials were continuously fed at the same feeding rate (0.857 kg / h for difluoroacetyl fluoride and 0.85 kg / h for fluorochlorosulfonyl fluoride). The temperature of reactor 9 was controlled at 37°C and the temperature of cyclization reactor 12 was controlled at 15°C. The reactor was run continuously for 8 hours.

[0052] Results: Periodic fluctuations (±3℃) in the outlet temperature of the single-stage reactor were observed during the reaction, indicating that the exothermic reaction was not smoothly extracted as in the three-stage gradient temperature control. After 8 hours of reaction, the organic phase at the bottom of the cyclization vessel 12 was collected and distilled to obtain 1.363 kg of tetrafluoroethane-β-sulfonyl lactone product. The yield was 81.50% based on fluorochlorosulfonyl, and its purity was 96.25%. Compared with Example 1, the yield decreased and the purity was also significantly reduced.

Claims

1. A method for preparing tetrafluoroethane-β-sulfonolactone, characterized in that, Includes the following steps: Step 1: Under the action of Lewis base catalysis, difluoroacetyl fluoride and fluorochlorosulfonyl undergo a nucleophilic substitution reaction in an organic solvent. During the reaction, the generated hydrogen chloride is removed under the drive of temperature and negative pressure to obtain the intermediate 2-(fluorosulfonyl)difluoroacetyl fluoride. The Lewis base catalytic system consists of tri-tert-butylphosphine, tetrabutylphosphine chloride, and anhydrous KF, with a molar ratio of tri-tert-butylphosphine, tetrabutylphosphine chloride, and anhydrous KF of 1:0.3~0.5:0.5~0.

8. Step 2: Under the action of Lewis acid catalysis, the intermediate obtained in Step 1 undergoes an intramolecular ring-closing reaction in an organic solvent. After the reaction is completed, the target fraction is collected by distillation to obtain tetrafluoroethane-β-sulfonolactone. The Lewis acid catalytic system consists of tris(pentafluorophenyl)borane, boron trifluoride acetonitrile complex, and perfluorobutylsulfonyl fluoride, with a molar ratio of tris(pentafluorophenyl)borane, boron trifluoride acetonitrile complex, and perfluorobutylsulfonyl fluoride of 1:0.2~0.5:0.1~0.

3.

2. The method for preparing tetrafluoroethane-β-sulfonolactone according to claim 1, characterized in that, In step one, the molar ratio of difluoroacetyl fluoride to fluorochlorosulfonyl is 1.1~1.3:

1.

3. The method for preparing tetrafluoroethane-β-sulfonyl lactone according to claim 1, characterized in that, The molar ratio of tri-tert-butylphosphine to fluorochlorosulfonyl is 0.03~0.05:

1.

4. The method for preparing tetrafluoroethane-β-sulfonolactone according to claim 3, characterized in that, In step one, the organic solvent is trifluorotoluene or cyclohexane; the reaction temperature is 35~45℃; the reaction is carried out in a continuous reaction device, and the temperature of the material in the primary reactor, secondary reactor and tertiary reactor is controlled at 30~40℃, 25~35℃ and 30~40℃ respectively; the reaction system is kept under slight negative pressure.

5. The method for preparing tetrafluoroethane-β-sulfonyl lactone according to claim 4, characterized in that, The induction rate for difluoroacetyl fluoride is 0.455~1.075 kg / h, and the induction rate for fluorochlorosulfonyl is 0.5~1 kg / h.

6. The method for preparing tetrafluoroethane-β-sulfonolactone according to claim 1, characterized in that, The molar ratio of tris(pentafluorophenyl)borane to fluorochlorosulfonyl in step one is 0.01~0.03:

1.

7. The method for preparing tetrafluoroethane-β-sulfonolactone according to claim 6, characterized in that, In step two, the organic solvent is trifluorotoluene or cyclohexane; the ring-closing reaction is carried out in a cyclization reactor at a temperature of 10-20°C, and a condenser is installed at the top of the cyclization reactor at a temperature of 8-18°C.

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