Method and device for continuously producing high-purity methylsulfonyl fluoride

Abstract

The invention discloses a method and a device for continuously producing high-purity methylsulfonyl fluoride. The method for continuously producing high-purity methylsulfonyl fluoride comprises the following steps: uniformly mixing methylsulfonyl chloride with a catalyst, and preheating to 80-160 DEG C to obtain a mixed solution; carrying out fluorination reaction on the mixed solution and a fluorinating agent at 80-160 DEG C, and collecting a generated gas-phase product in time in the reaction process; cooling the collected gas-phase product, and then carrying out gas-liquid separation to obtain a liquid-phase methylsulfonyl fluoride crude product; and heating the liquid-phase methylsulfonyl fluoride crude product to 123-124 DEG C to partially vaporize the liquid-phase methylsulfonyl fluoride crude product, and condensing the generated steam to obtain the high-purity methylsulfonyl fluoride. The method realizes continuous production of methylsulfonyl fluoride, not only shortens the reaction period, but also has the advantages of low cost, low energy consumption, high product quality and the like.

Description

Technical Field

[0001] This invention belongs to the field of fine chemicals, and in particular relates to a method and apparatus for the continuous production of high-purity methanesulfonyl fluoride. Background Technology

[0002] Methylsulfonyl fluoride (CH3SO2F) is an important raw material for fine chemical synthesis. It has a boiling point of 123-124℃, is insoluble in water but soluble in hydrogen fluoride, and is a crucial raw material for the electrochemical fluorination preparation of trifluoromethylsulfonyl fluoride. Currently, the main method for preparing methylsulfonyl fluoride involves using methylsulfonyl chloride as a raw material and carrying out a fluorination reaction in an aqueous solution of potassium fluoride. For example, Chinese patent CN112742337A discloses an apparatus and method for the continuous reaction preparation of methylsulfonyl fluoride, where methylsulfonyl chloride and an aqueous solution of potassium fluoride react. While this method can achieve continuous production, the presence of water in the system leads to partial hydrolysis of both methylsulfonyl chloride and methylsulfonyl fluoride. Subsequent dehydration during purification requires significant energy consumption, and the reaction is not homogeneous, resulting in incomplete reaction. The byproduct potassium chloride contains a small amount of potassium fluoride, which must be treated before utilization. Furthermore, the mother liquor also contains a large amount of potassium chloride; when potassium fluoride is dissolved again in the mother liquor, a large amount of solid potassium chloride precipitates, affecting reaction efficiency.

[0003] For example, Chinese patent CN112661676A discloses a method for preparing methanesulfonyl fluoride from methanesulfonyl chloride. Because it is a batch reaction, not only is the reaction cycle long and it is difficult to scale up, but the concentration of methanesulfonyl chloride also decreases as the reaction proceeds, and the reaction efficiency also decreases, making it difficult to obtain high-purity methanesulfonyl fluoride. The byproduct hydrogen chloride also contains a small amount of hydrogen fluoride impurities, which are difficult to use directly. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide a method and apparatus for continuous production of high-purity methanesulfonyl fluoride, aiming to solve the technical problems of long reaction cycle, low efficiency and low purity in the existing methanesulfonyl fluoride preparation methods.

[0005] The objective of this invention is achieved through the following technical solution: A method for continuous production of high-purity methanesulfonyl fluoride includes the following steps: (1) Mix methanesulfonyl chloride and catalyst evenly and preheat to 80~160℃ to obtain a mixed solution; carry out fluorination reaction with fluorinating agent at 80~160℃, and collect the generated gaseous products in time during the reaction. The chemical structural formula of the catalyst is MCl. x M is Fe, Ti or Mo, and x ≥ 3; The fluorinating agent is anhydrous hydrogen fluoride, or a mixture of anhydrous hydrogen fluoride and a protective gas; (2) The collected gaseous product was cooled and then separated into liquid phase to obtain crude liquid methanesulfonyl fluoride; (3) Heat the crude liquid methanesulfonyl fluoride to 123~124℃ to partially vaporize it, and condense the generated vapor to obtain high-purity methanesulfonyl fluoride.

[0006] Preferably, the mass ratio of the catalyst to methanesulfonyl chloride in step (1) is 1~10:1000.

[0007] Preferably, in step (1), when the fluorinating agent is anhydrous hydrogen fluoride, the fluorination reaction is carried out at a pressure of -2000 to -25 Pa.

[0008] Preferably, in step (1), when the fluorinating agent is a mixture of anhydrous hydrogen fluoride and a protective gas, the fluorination reaction is carried out at atmospheric pressure.

[0009] Preferably, the protective gas in step (1) is an inert gas or nitrogen.

[0010] In this invention, the reaction equation for the preparation of methanesulfonyl fluoride is as follows: CH3SO2Cl+HF CH3SO2F + HCl (I) In the formula, M represents at least one of the three elements Fe, Ti, and Mo, and x ≥ 3.

[0011] Equation (I) indicates a reversible reaction. However, hydrogen chloride has limited solubility in methanesulfonyl chloride and methanesulfonyl fluoride, meaning most of the hydrogen chloride exists in the gaseous phase within the reactor. If the hydrogen chloride is not removed promptly, the forward reaction will be inhibited, hindering the formation of methanesulfonyl fluoride. Therefore, the reaction pressure in Equation (I) should be either atmospheric pressure or a slightly negative pressure. If pure hydrogen fluoride gas is introduced during the reaction, a slightly negative pressure is preferable; conversely, if a mixture of hydrogen fluoride and an inert gas is introduced, atmospheric pressure is preferable.

[0012] Preferably, in step (2), the collected gaseous products are cooled to 50~77°C and then gas-liquid separation is performed.

[0013] An apparatus for carrying out the above-described method for continuous production of high-purity methanesulfonyl fluoride includes a premixing unit, a fluorination reaction unit, a deacidification unit, and a distillation unit connected in sequence. The premixing unit is used to mix the methanesulfonyl chloride with a fluorinating agent to form a mixed solution; The fluorination reaction unit is connected to the outlet of the premixing unit and is used to receive the mixed solution and carry out the fluorination reaction. The deacidification unit is connected to the outlet of the fluorination reaction unit and is used to perform gas-liquid separation on the obtained gas phase product, thereby separating the crude liquid phase methanesulfonyl fluoride. The distillation unit is connected to the outlet of the deacidification unit and is used to vaporize and condense the crude liquid methanesulfonyl fluoride to obtain high-purity methanesulfonyl fluoride distillate.

[0014] Preferably, the premixing unit includes a premixing reactor, a first inlet, a second inlet, and a first stirring motor; therefore, the first inlet and the second inlet are located at the top of the premixing reactor, and the first stirring motor is located at the top of the premixing reactor, with its stirring shaft extending into the reactor.

[0015] Preferably, the fluorination reaction unit includes a fluorination reactor, a second stirring motor, a filter, and a fluorinating agent feed pipe; the inlet of the filter is connected to the bottom of the fluorination reactor via a pipe, and its outlet is connected to the top of the fluorination reactor via a pipe; the end of the fluorinating agent feed pipe extends to the inner bottom of the fluorination reactor; the second stirring motor is located at the top of the fluorination reactor, and its stirring shaft extends into the reactor.

[0016] Preferably, the end of the fluorinating agent feed pipe is provided with a porous screen.

[0017] In the reaction process of formula (I), due to the presence of trace amounts of moisture in the raw materials, the catalyst undergoes hydrolysis and deactivates. The reaction equation is as follows: MClx + H₂O → MOCl x-2 +2HCl Deactivated catalyst MOCl x-2 The deactivated catalyst remains in the reaction system in solid form. If it is not separated in time, it will not only affect the reaction efficiency, but also adhere to the inner wall of the reactor, affecting heat transfer and increasing energy consumption. Therefore, an external circulation device equipped with a filter is connected to the pre-fluorination reactor. The deactivated catalyst remains in the filter in solid form, and the filtrate is returned to the pre-fluorination reactor to continue the reaction.

[0018] Preferably, the deacidification unit includes a first packed tower, a first condenser, and a first reboiler, wherein the first reboiler is disposed at the bottom of the first packed tower and the first condenser is disposed at the top of the first packed tower.

[0019] Preferably, the distillation unit includes a second packed column, a second condenser, and a second reboiler, with the second reboiler located at the bottom of the second packed column and the second condenser located at the top of the second packed column.

[0020] Compared with the prior art, the beneficial effects of the present invention include: (1) The present invention adopts a four-step continuous operation of “premixing → prefluorination → deacidification → distillation”, with constant reactor liquid level and controllable feed rate, realizing continuous production of methanesulfonyl fluoride, and the production efficiency is higher than that of intermittent operation; (2) The present invention uses anhydrous hydrogen fluoride gas instead of potassium fluoride aqueous solution, which controls the moisture at the source and avoids the impurities generated by hydrolysis from the reaction mechanism. This not only reduces the energy consumption of subsequent dehydration, but also improves the yield of methanesulfonyl fluoride. (3) The catalyst described in this invention has high catalyst activity and good selectivity, and the deactivated catalyst is transferred in real time through an external circulation filter, thereby maintaining the reaction efficiency; (4) The present invention produces less waste. Compared with the potassium fluoride aqueous solution method, it does not produce a large amount of fluoride-containing waste residue and wastewater, thus saving energy, reducing emissions, and being green and environmentally friendly. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the apparatus for implementing the method of continuous production of high-purity methanesulfonyl fluoride according to the present invention; Figure 2 This is a schematic diagram of the end structure of the fluorinating agent feed pipe; In the diagram, 11-premixed reactor, 12-first feed inlet, 13-second feed inlet, 14-first stirring motor, 21-fluorination reactor, 22-second stirring motor, 23-filter, 24-fluorinating agent feed pipe, 25-porous screen, 31-first packed tower, 32-first condenser, 33-first reboiler, 41-second packed tower, 42-second condenser, 43-second reboiler. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0023] See Figure 1 , Figure 1 This is a schematic diagram of the apparatus for the continuous production of high-purity methanesulfonyl fluoride according to the present invention, including a premixing unit 1, a fluorination reaction unit 2, a deacidification unit 3, and a distillation unit 4 connected in sequence. The premixing unit 1 is used to mix the methanesulfonyl chloride with the fluorinating agent to form a mixed solution; The fluorination reaction unit 2 is connected to the outlet of the premixing unit 1 and is used to receive the mixed solution and carry out the fluorination reaction. The deacidification unit 3 is connected to the outlet of the fluorination reaction unit 2 and is used to perform gas-liquid separation on the obtained gas phase product, thereby separating the crude liquid phase methanesulfonyl fluoride. The distillation unit 4 is connected to the outlet of the deacidification unit 3 and is used to vaporize and condense the crude liquid methanesulfonyl fluoride to obtain high-purity methanesulfonyl fluoride distillate.

[0024] Methylsulfonyl chloride and catalyst are mixed in the premixing unit 1 to obtain a mixed solution. The mixed solution is then transferred through the outlet of the premixing unit 1 to the fluorination reaction unit 2, where it undergoes a fluorination reaction with a fluorinating agent. The gaseous product generated by the fluorination reaction is then sent to the deacidification unit 3, where the byproducts hydrogen chloride and hydrofluoric acid are removed to obtain a crude liquid-phase methylsulfonyl fluoride. Finally, the crude product is vaporized and condensed in the distillation unit 4 to obtain a high-purity methylsulfonyl fluoride distillate.

[0025] Furthermore, the premixing unit 1 includes a premixing reactor 11, a first feed inlet 12, a second feed inlet 13, and a first stirring motor 14; therefore, the first feed inlet 11 and the second feed inlet 12 are located at the top of the premixing reactor 11, and the first stirring motor 14 is located at the top of the premixing reactor 11, with its stirring shaft extending into the reactor.

[0026] Methylsulfonyl chloride and catalyst are fed into the premixing reactor 11 through the first inlet 12 and the second inlet 13, respectively, and are stirred by the first stirring motor 14 to make them mix evenly.

[0027] Furthermore, the fluorination reaction unit 2 includes a fluorination reactor 21, a second stirring motor 22, a filter 23, and a fluorinating agent feed pipe 24; the inlet of the filter 23 is connected to the bottom of the fluorination reactor 21 through a pipe, and its outlet is connected to the top of the fluorination reactor 21 through a pipe; the end of the fluorinating agent feed pipe 24 extends to the inner bottom of the fluorination reactor 21; the second stirring motor 22 is located at the top of the fluorination reactor 21, and its stirring shaft extends into the reactor.

[0028] Under the stirring action of the second stirring motor 22, the fluorination reaction takes place in the fluorination reactor 21. The reacted material is filtered through the filter 23 to remove the deactivated catalyst, and the resulting filtrate is returned to the fluorination reactor 21 for recycling. In addition, the end of the fluorinating agent feed pipe 24 extends to the bottom of the fluorination reactor 21, allowing the fluorinating agent to directly enter the liquid phase containing methanesulfonyl chloride, thereby achieving full contact.

[0029] Furthermore, in order to increase the contact area between anhydrous hydrogen fluoride and methanesulfonyl chloride, and to extend the service life of the fluorinating agent feed pipe 24, a porous screen 25 is provided at the end of the fluorinating agent feed pipe 24, and the porous screen is made of a corrosion-resistant material.

[0030] Furthermore, the deacidification unit 3 includes a first packed tower 31, a first condenser 32, and a first reboiler 33. The first reboiler 33 is disposed at the bottom of the first packed tower 31, and the first condenser 32 is disposed at the top of the first packed tower 31.

[0031] The gaseous products from the fluorination reaction enter the deacidification unit 3. This gaseous phase mainly consists of methanesulfonyl fluoride, methanesulfonyl chloride, hydrogen chloride, and hydrogen fluoride. In the first packed column 31, the components are separated based on their boiling point differences: the low-boiling-point hydrogen chloride and a small amount of unreacted hydrogen fluoride remain gaseous after passing through the first condenser 32 and are discharged from the top of the column; while the main product, methanesulfonyl fluoride, and a small amount of methanesulfonyl chloride, due to their higher boiling points, condense into a liquid phase and accumulate at the bottom of the column. The first reboiler 33 is used to maintain the bottom temperature of the column and provide the necessary stripping steam.

[0032] Furthermore, the distillation unit 4 includes a second packed column 41, a second condenser 42, and a second reboiler 43. The second reboiler 43 is disposed at the bottom of the second packed column 41, and the second condenser 42 is disposed at the top of the second packed column 41.

[0033] The crude liquid methanesulfonyl fluoride is sent to the distillation unit 4. In the second packed column 41, the material is heated and vaporized by the second reboiler 43. Since the boiling points of methanesulfonyl fluoride and methanesulfonyl chloride differ by about 40°C, the two can be effectively separated: the low-boiling-point component, methanesulfonyl fluoride, is distilled off from the top of the column as a light component and collected after being condensed by the second condenser 42; while the high-boiling-point methanesulfonyl chloride remains at the bottom of the column as a heavy component.

[0034] See also Figure 2 , Figure 2 The diagram shows the structure at the end of the fluorinating agent feed pipe. As we can see, a porous screen is installed at the end, which can significantly increase the contact area between the fluorinating agent and the liquid phase of methanesulfonyl chloride.

[0035] Example 1 A method for continuous production of high-purity methanesulfonyl fluoride, comprising the following specific steps: (1) Add 550 kg of methanesulfonyl chloride and 0.6 kg of ferric chloride to the premixed reactor, start stirring, and preheat to 140 °C to completely dissolve the ferric chloride. Add the mixed solution of methanesulfonyl chloride and ferric chloride to the prefluorination reactor, stir and heat to 140 °C, and introduce anhydrous hydrogen fluoride to cause the methanesulfonyl chloride to undergo a fluorination reaction. The system pressure is -1000 kPa. Adjust the feed rate to keep the liquid level in the prefluorination reactor constant (the liquid level does not exceed 1 / 2 of the reactor volume). The distillate begins to be discharged after 25 min. Collect the distillate. (2) The distillate produced enters the deacidification tower, where it is cooled to 70°C and then subjected to gas-liquid separation. The light components, hydrogen chloride and hydrogen fluoride, are discharged from the top of the deacidification tower, while the heavy components are transported to the distillation tower and treated by the reboiler. The heavy components are then heated to 124°C. The low-boiling-point methanesulfonyl fluoride is collected from the top of the distillation tower, while the high-boiling-point methanesulfonyl chloride remains in the reboiler and is pumped into the methanesulfonyl chloride storage tank for recycling.

[0036] The methanesulfonyl fluoride prepared in Example 1 was analyzed by gas chromatography and found to have a purity of 99.68%, a moisture content of 47 ppm, a chloride ion content of 182 ppm, and a purity of 90.21% for the recovered methanesulfonyl chloride. The yield of methanesulfonyl fluoride in one production cycle was 96.37%.

[0037] Comparative Example 1 The only difference between Comparative Example 1 and Example 1 is that ferric chloride is replaced with an equal amount of potassium fluoride, while the other steps and operations are the same as in Example 1.

[0038] The methylsulfonyl fluoride prepared in Comparative Example 1 was analyzed by gas chromatography and found to have a purity of 10.49%, a moisture content of 58 ppm, a chloride ion content of 225 ppm, and a purity of 95.6% for the recovered methylsulfonyl chloride. The yield of methylsulfonyl fluoride in one production cycle was 9.12%.

[0039] Example 2 A method for continuous production of high-purity methanesulfonyl fluoride, comprising the following specific steps: (1) Add 550 kg of methanesulfonyl chloride and 0.6 kg of titanium tetrachloride to the premixed reactor, start stirring, and preheat to 130 °C to completely dissolve the titanium tetrachloride. Add the mixed solution of methanesulfonyl chloride and titanium tetrachloride to the prefluorination reactor, stir and heat to 130 °C, and introduce anhydrous hydrogen fluoride to cause the methanesulfonyl chloride to undergo a fluorination reaction. The system pressure is -1000 kPa. Adjust the feed rate to keep the liquid level in the prefluorination reactor constant (the liquid level does not exceed 1 / 2 of the reactor volume). The distillate begins to be discharged after 35 min. Collect the distillate. (2) The distillate produced enters the deacidification tower, where it is cooled to 60°C and then subjected to gas-liquid separation. The light components, hydrogen chloride and hydrogen fluoride, are discharged from the top of the deacidification tower, while the heavy components are transported to the distillation tower and treated by the reboiler. The heavy components are then heated to 124°C. The low-boiling-point methanesulfonyl fluoride is collected from the top of the distillation tower, while the high-boiling-point methanesulfonyl chloride remains in the reboiler and is pumped into the methanesulfonyl chloride storage tank for recycling.

[0040] The methanesulfonyl fluoride prepared in Example 2 was analyzed by gas chromatography and found to have a purity of 99.72%, a moisture content of 45 ppm, a chloride ion content of 164 ppm, and a purity of 91.95% for the recovered methanesulfonyl chloride. The yield of methanesulfonyl fluoride in one production cycle was 96.25%.

[0041] Comparative Example 2 The only difference between Comparative Example 2 and Example 2 is that titanium tetrachloride is replaced with an equal amount of antimony trifluoride; the other steps and operations are the same as in Example 2.

[0042] The methylsulfonyl fluoride prepared in Comparative Example 2 was analyzed by gas chromatography and found to have a purity of 8.72%, a moisture content of 71 ppm, a chloride ion content of 187 ppm, and a purity of 96.3% for the recovered methylsulfonyl chloride. The yield of methylsulfonyl fluoride in one production cycle was 7.45%.

[0043] Example 3 A method for continuous production of high-purity methanesulfonyl fluoride, comprising the following specific steps: (1) Add 550 kg of methanesulfonyl chloride and 0.6 kg of molybdenum pentachloride to the premixed reactor, start stirring, and preheat to 120 °C to completely dissolve the molybdenum pentachloride. Add the mixed solution of methanesulfonyl chloride and molybdenum pentachloride to the prefluorination reactor, stir and heat to 120 °C, and introduce anhydrous hydrogen fluoride to cause the methanesulfonyl chloride to undergo a fluorination reaction. The system pressure is -1000 kPa. Adjust the feed rate to keep the liquid level in the prefluorination reactor constant (the liquid level does not exceed 1 / 2 of the reactor volume). The distillate begins to be discharged after 40 min. Collect the distillate. (2) The distillate produced enters the deacidification tower, where it is cooled to 55°C and then subjected to gas-liquid separation. The light components, hydrogen chloride and hydrogen fluoride, are discharged from the top of the deacidification tower, while the heavy components are transported to the distillation tower and treated by the reboiler. The heavy components are then heated to 123°C. The low-boiling-point methylsulfonyl fluoride is collected from the top of the distillation tower, while the high-boiling-point methylsulfonyl chloride remains in the reboiler and is pumped into the methylsulfonyl chloride storage tank for recycling.

[0044] The methanesulfonyl fluoride prepared in Example 3 was analyzed by gas chromatography and found to have a purity of 99.68%, a moisture content of 42 ppm, a chloride ion content of 178 ppm, and a purity of 92.30% for the recovered methanesulfonyl chloride. The yield of methanesulfonyl fluoride in one production cycle was 96.78%.

[0045] Comparative Example 3 The only difference between Comparative Example 3 and Example 3 is that molybdenum pentachloride is replaced with an equal amount of antimony pentafluoride; the other steps and operations are the same as in Example 3.

[0046] The methylsulfonyl fluoride prepared in Comparative Example 3 was analyzed by gas chromatography and found to have a purity of 4.86%, a moisture content of 85 ppm, a chloride ion content of 128 ppm, and a purity of 95.1% for the recovered methylsulfonyl chloride. The yield of methylsulfonyl fluoride in one production cycle was 4.13%.

[0047] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for continuously producing high purity methylsulfonyl fluoride, characterized by, The method comprises the following steps: (1) uniformly mixing methylsulfonyl chloride with a catalyst, preheating to 80-160 DEG C to obtain a mixed solution; carrying out fluorination reaction of the mixed solution with a fluorination agent at 80-160 DEG C, and collecting the generated gas phase product in time during the reaction; The chemical structure of the catalyst is MCI x , M is Fe, Ti or Mo, x > 3; The fluorination agent is anhydrous hydrogen fluoride, or a mixture of anhydrous hydrogen fluoride and a protective gas; (2) cooling the collected gas phase product, and then carrying out gas-liquid separation to obtain liquid methylsulfonyl fluoride crude product; (3) heating the liquid methylsulfonyl fluoride crude product to 123-124 DEG C to partially vaporize it, and condensing the generated steam to obtain high-purity methylsulfonyl fluoride.

2. The method of continuously producing high purity methylsulfonyl fluoride according to claim 1, wherein The mass ratio of the catalyst to methylsulfonyl chloride in step (1) is 1-10:1000; and / or The protective gas in step (1) is inert gas or nitrogen.

3. The method of continuously producing high purity methylsulfonyl fluoride according to claim 1, characterized by, In step (1), when the fluorination agent is anhydrous hydrogen fluoride, the fluorination reaction is carried out at a pressure of -2000 to -25 Pa; and / or In step (1), when the fluorination agent is a mixture of anhydrous hydrogen fluoride and a protective gas, the fluorination reaction is carried out at normal pressure.

4. The method of continuously producing high purity methylsulfonyl fluoride according to claim 1, wherein In step (2), the collected gas phase product is cooled to 50-77 DEG C, and then gas-liquid separation is carried out.

5. An apparatus for carrying out the process for the continuous production of high purity methylsulfonyl fluoride according to any one of claims 1 to 4, characterized in that The method comprises the following steps: The pre-mixing unit is used for mixing the methylsulfonyl chloride with the fluorination agent to form a mixed solution; The fluorination reaction unit is connected with the discharge port of the pre-mixing unit, and is used for receiving the mixed solution and carrying out fluorination reaction; The deacidification unit is connected with the discharge port of the fluorination reaction unit, and is used for carrying out gas-liquid separation on the obtained gas phase product, so as to separate out the liquid methylsulfonyl fluoride crude product; The rectification unit is connected with the discharge port of the deacidification unit, and is used for vaporizing and condensing the liquid methylsulfonyl fluoride crude product to obtain high-purity methylsulfonyl fluoride distillate.

6. The apparatus of claim 5, wherein, The pre-mixing unit comprises a pre-mixing reactor, a first feeding port, a second feeding port and a first stirring motor; the first feeding port and the second feeding port are located at the top end of the pre-mixing reactor, and the first stirring motor is arranged at the top of the pre-mixing reactor, with the stirring shaft extending into the reactor.

7. The apparatus of claim 5, wherein, The fluorination reaction unit comprises a fluorination reactor, a second stirring motor, a filter and a fluorination agent feeding pipe; the feeding port of the filter is connected with the bottom of the fluorination reactor through a pipeline, the discharge port of the filter is connected with the top of the fluorination reactor through a pipeline, and the end of the fluorination agent feeding pipe extends to the inner bottom of the fluorination reactor; The second stirring motor is arranged at the top of the fluorination reactor, with the stirring shaft extending into the reactor.

8. The apparatus of claim 7, wherein, The end of the fluorination agent feeding pipe is provided with a porous screen.

9. The apparatus of claim 5, wherein, The deacidification unit comprises a first packed column, a first condenser and a first reboiler; the first reboiler is arranged at the bottom of the first packed column, and the first condenser is arranged at the top of the first packed column.

10. The apparatus of claim 5, wherein, The rectification unit comprises a second packed column, a second condenser and a second reboiler; the second reboiler is arranged at the bottom of the second packed column, and the second condenser is arranged at the top of the second packed column.

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