A method for producing a bisfluorosulfonylimide salt or bisfluorosulfonylimide acid using a microchannel column reactor

Abstract

This invention belongs to the field of lithium-ion battery technology and relates to a method for preparing bis(fluorosulfonyl)imide salt or acid using a microchannel tower reactor. The steps are as follows: 1) At a temperature of 0-10℃ and atmospheric pressure, an alkali metal fluoride is dissolved in anhydrous hydrogen fluoride or anhydrous hydrogen fluoride is used directly. The mixed solution or anhydrous hydrogen fluoride is then heated to 40-50℃ and 7-11 bar to obtain material A; 2) Bis(fluorosulfonyl)imide acid is added to 90-100℃ and 7-11 bar to obtain material B; 3) Material A and material B are added separately from the bottom into the microchannel tower reactor, first entering a premixing pipe, then passing through a 300-600 μm microchannel, and reacting for 20-30 minutes at 90-100℃ and 7-11 bar. The reaction solution is depressurized to release HF and HCl, and the HF is condensed and recovered. The liquid is intermittently cooled and crystallized by ultrasonication to 30-50℃, and filtered to obtain bis(fluorosulfonyl)imide salt or acid. The filtrate is recycled. This method shortens a multi-step reaction into a single continuous reaction, avoids organic solvents, has a short reaction time, and can be widely applied.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery technology and relates to a method for preparing bis(fluorosulfonyl)imide salt or bis(fluorosulfonyl)imide acid using a microchannel tower reactor. Background Technology

[0002] Lithium bis(fluorosulfonyl)imide (LiFSI) is a novel electrolyte solute that exhibits superior thermal stability and higher conductivity compared to traditional lithium hexafluorophosphate (LiPF6).

[0003] Traditional methods synthesize dichlorosulfonylimide acid from raw materials such as sulfonamides, thionyl chloride, and chlorosulfonic acid; then, dichlorosulfonylimide acid is synthesized by reacting it with fluorine-containing substances; finally, a basic lithium salt (such as lithium carbonate) is added to obtain the corresponding lithium difluorosulfonylimide salt, and the solid product is obtained by crystallization purification and drying. This method suffers from drawbacks such as a long process flow, long reaction time, and unstable product purity. Therefore, researchers have been continuously investigating new preparation methods.

[0004] For example, patent document CN120757082A provides a method for preparing bis(fluorosulfonyl)imide salts. Hydrofluoric acid, an alkali metal fluoride, and bis(fluorosulfonyl)imide are reacted under sealed conditions at a temperature above 100°C. After the reaction, the temperature is lowered to below 10°C, and a filter cake is obtained through a first filtration. The temperature is then raised to above 100°C, and a second filtration is performed to obtain the filtrate. After impurity removal, bis(fluorosulfonyl)imide salt particles or a bis(fluorosulfonyl)imide salt solution are obtained. This method separates the product and impurities by controlling the reaction temperature and the temperatures of the two filtrations after the reaction, utilizing the crystallization characteristics and solubility of each component in the reaction system at different temperatures, achieving a solvent-free one-pot preparation of high-purity bis(fluorosulfonyl)imide salts. However, this method has drawbacks such as the addition of excessive lithium fluoride and bis(fluorosulfonyl)imide, lithium fluoride residues in the bis(fluorosulfonyl)imide, discontinuous reaction, high reaction temperature, and the addition of highly corrosive hydrofluoric acid.

[0005] Patent document CN119118076A discloses a method for preparing lithium bis(fluorosulfonyl)imide, comprising the following steps: Step 1: Chlorosulfonic acid and chlorosulfonyl isocyanate react to generate bis(fluorosulfonyl)imide under the action of a first catalyst; Step 2: Hydrogen fluoride gas is introduced into the bis(fluorosulfonyl)imide generated in Step 1, and bis(fluorosulfonyl)imide is obtained under the action of a first catalyst; Step 3: A first lithium salt is added to an organic solvent, and the bis(fluorosulfonyl)imide obtained in Step 2 is added during stirring, followed by ion exchange to obtain lithium bis(fluorosulfonyl)imide. This method has a high conversion rate, reduces the amount of catalyst used, simplifies the steps, and further improves the yield. However, this method is still a traditional method, with a long process and the introduction of solvents, resulting in a high residual solvent in the product.

[0006] Therefore, developing a process for producing bisfluorosulfonylimine acid or salt that has a short process flow, avoids the introduction of large amounts of good and bad solvents, has a short reaction time, and can achieve continuous reaction is a technical problem that urgently needs to be solved. Summary of the Invention

[0007] Based on this, the purpose of the present invention is to provide a method for preparing bis(fluorosulfonyl)imide salt or bis(fluorosulfonyl)imide hydrochloride using a microchannel tower reactor. This method has a short process flow, does not introduce good or bad solvents, has a short reaction time, and can achieve continuous reaction.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides a method for preparing bis(fluorosulfonyl)imide salts using a microchannel tower reactor, comprising the following steps: S1, Dissolve alkali metal fluoride in anhydrous hydrogen fluoride to obtain mixture A; Heat and pressurize mixture A to obtain material A; S2, mix dichlorosulfonyl imide acid with circulating liquid to obtain mixture B; heat and pressurize dichlorosulfonyl imide acid or mixture B to obtain material B; S3, add material A from S1 and material B from S2 into the microchannel tower reactor from the bottom, and obtain the reaction solution after heating and pressurizing the reaction. The reaction liquids described in S4 and S3 are depressurized to obtain gas and liquid; the hydrogen fluoride in the gas is condensed and recovered and then recycled to S1 as a raw material for reuse; the liquid is cooled, crystallized, and filtered to obtain bis(fluorosulfonyl)imide salt and filtrate; the filtrate is recycled to S2 as a circulating liquid for reuse.

[0009] Furthermore, the temperature used to prepare the mixture A in S1 is 0~10℃ and the pressure is atmospheric pressure; the mixture A is heated to 40~50℃ and pressurized to 7~11 bar to obtain material A.

[0010] Further, in S2, the dichlorosulfonamide acid and the circulating liquid are mixed in a self-cleaning static mixer with a gradually expanding flow channel, and the mixture is mixed by a micro-tilt spiral blade structure to obtain mixture B; the dichlorosulfonamide acid or the mixture B is heated to 90~100℃ and pressurized to 7~11 bar to obtain material B.

[0011] Furthermore, the temperature of the heating and pressurizing reaction described in S3 is 90~100℃, the pressure is 7~11 bar, and the reaction time is 20~30 min.

[0012] Furthermore, the microchannel tower reactor described in S3 is provided with a premixing pipe and a packing layer. The packing layer includes a packing support and packing. The packing support is used to disperse and support the packing. The gaps between the packings form microchannels. The size of the microchannels is 300~600μm. After materials A and B are added to the microchannel tower reactor from the bottom, they first enter the premixing pipe for premixing. After premixing, they flow out from the premixing pipe and are divided by the microchannels before reacting.

[0013] Furthermore, the microchannel tower reactor includes an upper tube box, a shell, lugs, packing, packing support, and a lower tube box; Further, the microchannel tower reactor includes an upper tube box, a shell, lugs, packing, packing supports, and a lower tube box; the upper and lower tube boxes are connected to the shell via flanges; the shell contains a packing layer composed of packing and packing supports, the packing supports being silicon carbide microporous structures used to disperse and support the packing, the packing preferably being made of silicon carbide, the gaps between the packing forming microchannels with a size of 300~600μm; the lower tube box is equipped with material inlet 1, inlet 2, a tubular distribution plate, and a premixing pipe; the tubular distribution plate is welded and fixed to the lower tube box cylinder, and has 21 pipe joints evenly distributed in 4 layers, the pipe joints communicating with the premixing pipe, material A enters the reactor through inlet 1, and then enters the premixing pipe through the pipe joints; the premixing pipe consists of a fixed plate, a fixed shaft, and a membrane. The reactor consists of a membrane sleeve, a secondary distribution tube, and bearings. The membrane sleeve is welded to a fixed plate, and the fixed shaft is also welded to the fixed plate via two layers of reinforcing plates. The secondary distribution tube is fixed between the fixed shaft and the pipe joint via two bearings. The secondary distribution tube has 192 small holes, all facing downwards at a uniform angle. Material A is redistributed through the secondary distribution tube. Material B enters the reactor from inlet 2 and then enters the gap between the membrane sleeve and the secondary distribution tube from the bottom of the membrane sleeve, where it is thoroughly mixed with material A. After material A and material B are mixed in the premixing pipe, the mixture enters the packing layer from the top of the membrane sleeve through the gap between the membrane sleeve and the fixed shaft. It is further divided by the microchannels formed by the 300-600 μm gaps in the packing layer, allowing the two materials to fully contact each other and react.

[0014] Further, in step S4, the reaction solution is depressurized to 55-65 kPa to obtain gas and liquid; the cooling crystallization is ultrasonic intermittent cooling crystallization at a temperature of 30-50°C.

[0015] Furthermore, the reaction molar ratio of the dichlorosulfonylimide acid, anhydrous hydrogen fluoride, and alkali metal fluoride is 1:(5~15):(0.7~0.9).

[0016] Furthermore, the alkali metal fluoride includes lithium fluoride, sodium fluoride, or potassium fluoride; the difluorosulfonyl imide salt includes lithium difluorosulfonyl imide, sodium difluorosulfonyl imide, or potassium difluorosulfonyl imide.

[0017] The present invention further provides a method for preparing bis(fluorosulfonyl)imide acid using a microchannel tower reactor. First, anhydrous hydrogen fluoride is heated and pressurized to obtain material A; then, the same steps S2 to S4 as in the method for preparing bis(fluorosulfonyl)imide salt using a microchannel tower reactor as described in any one of claims 1-6 are used to prepare bis(fluorosulfonyl)imide acid.

[0018] Further, the anhydrous hydrogen fluoride is heated to 40-50°C and pressurized to 7-11 bar to obtain material A.

[0019] Furthermore, the molar ratio of the dichlorosulfonylimide acid to anhydrous hydrogen fluoride is 1:(2~4).

[0020] The beneficial effects of this invention are: (1) One-step reaction synthesis: using alkali metal fluorides, dichlorosulfonylimide acid and anhydrous hydrogen fluoride as raw materials, dichlorosulfonylimide salt or dichlorosulfonylimide acid is directly generated in a microchannel tower reactor, avoiding the intermediate separation steps in the traditional multi-step process, simplifying the operation process and improving the overall yield.

[0021] (2) No organic solvents: No good or bad organic solvents need to be added during the entire reaction process. Only anhydrous hydrogen fluoride is used as a reactant and medium. Excess HF can be recovered and recycled after the reaction, and the filtrate can be reused, eliminating the risk of solvent residue and environmental pollution, and reducing production costs.

[0022] (3) Short reaction time: The material is fully reacted through the 300~600μm fine channel of the microreactor. Combined with the self-cleaning static mixer and silicon carbide packing support structure, the mass transfer and heat transfer efficiency is greatly improved. The reaction residence time is only 20~30 minutes, which is much shorter than the several hours of the traditional stirred tank process.

[0023] (4) Continuous production: It realizes continuous operation of the entire process from raw material preparation, feeding, reaction, degassing, crystallization to filtration and circulation. The equipment is easy to scale up and the production capacity can be flexibly adjusted. It overcomes the problems of batch difference and high energy consumption of intermittent operation and is suitable for large-scale industrial application. Attached Figure Description

[0024] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the microchannel tower reactor used in the embodiments of the present invention; Figure 2 This is a schematic diagram of the lower tube box structure of the microchannel tower reactor used in this embodiment of the invention; Figure 3 This is a schematic diagram of the cross-sectional structure of the tubular distribution plate and premixed pipeline in the lower tube box of the microchannel tower reactor used in this embodiment of the invention; Figure 4 A schematic diagram of a single premixed pipe structure in the lower tube box of the microchannel tower reactor used in this embodiment of the invention; Figure 5 This is a schematic diagram of the circumferential opening structure of the secondary distribution pipe in the premixing pipeline of the microchannel tower reactor used in the embodiments of the invention. Detailed Implementation

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. All mentioned embodiments are implemented based on the technical solutions of the present invention, and detailed implementation processes are given. However, it should be stated that the scope of protection of the present invention is not limited to the following embodiments. Unless otherwise specified, the experimental methods used in the following experimental examples are conventional methods; the materials and reagents used, unless otherwise specified, are commercially available reagents and materials; and unless otherwise specified, the room temperature or ambient temperature is 25±5℃.

[0027] The microchannel tower reactor used in the following embodiments of the present invention for the preparation of difluorosulfonylimide salts or difluorosulfonylimide acids is as follows: Figures 1-5 As shown. This microchannel tower reactor includes an upper tube box, a shell, lugs, packing, packing supports, and a lower tube box (…). Figure 1 The upper and lower pipe boxes are connected to the shell via flanges; the upper pipe box is equipped with a material outlet pipe; the shell contains a packing layer consisting of packing material and packing supports. The packing supports are made of silicon carbide microporous structure for dispersing and supporting the packing material. Silicon carbide is the preferred material for the packing material, and the gaps between the packing materials form microchannels with a size of 300~600μm; lugs are welded to the shell for equipment fixation. The lower pipe box is equipped with material inlet 1, inlet 2, a tubular distribution plate, and premixing pipes (…). Figure 2 The tubular distribution plate is welded and fixed to the lower pipe box cylinder, and 21 pipe joints are evenly distributed in 4 layers. The pipe joints are connected to the premixed pipeline. Figure 3 and Figure 4 Material A enters the reactor through inlet 1, and then enters the premixing pipeline through the pipe joint; the premixing pipeline consists of a fixed plate, a fixed shaft, a membrane sleeve, a secondary distribution pipe, and bearings. Figure 4 The membrane sleeve is welded to the fixed plate, and the fixed shaft is also welded to the fixed plate through two layers of stiffening plates. The secondary distribution pipe is fixed between the fixed shaft and the pipe joint by two upper and lower bearings. The secondary distribution pipe has 192 small holes, all of which are angled downwards. Figure 5With consistent angles, material A is redistributed through the secondary distribution pipe; material B enters the reactor from inlet 2, then enters the gap between the membrane sleeve and the secondary distribution pipe from the lower part of the membrane sleeve, mixing thoroughly and evenly with material A. After mixing in the premixing pipe, the mixture enters the packing layer from the upper part of the membrane sleeve through the gap between the membrane sleeve and the fixed shaft. It is further divided by the tiny channels formed by the 300~600μm gaps in the packing layer, ensuring full contact for reaction. The reaction liquid flows out from the material outlet of the upper tube box. The outflowing reaction liquid is depressurized to obtain gas and liquid; the hydrogen fluoride in the gas is condensed and recovered for recycling, and can be reused as a raw material for the preparation of material A; the liquid is cooled, crystallized, and filtered to obtain bis(fluorosulfonyl)imide salt / bis(fluorosulfonyl)imide acid and filtrate. The filtrate can be recycled as a circulating liquid for the preparation of material B.

[0028] Example 1

[0029] The preparation of lithium bis(fluorosulfonyl)imide using a microchannel tower reactor follows these steps: (1) Add 10kg lithium fluoride and 100kg anhydrous hydrogen fluoride to the dissolving tank and stir to dissolve. In order to maintain continuity, two dissolving tanks can be used alternately. The flow rate is 110kg / h and pressurized to 10bar by a pump. The raw material is indirectly heated to 50°C by heat transfer oil. This raw material is called material A. (2) The flow rate of 100 kg / h of dichlorosulfonimide acid is pressurized to 10 bar by a pump, and the circulating liquid from the subsequent process is also pressurized to 10 bar by a pump. The two are mixed in a self-cleaning static mixer with a gradually expanding channel. After being mixed by a micro-tilt spiral blade structure, it is indirectly heated to 90°C by heat transfer oil. This flow is called material B. (3) Material A enters the reactor from inlet 1 at the bottom of the reactor, and material B enters the reactor from inlet 2 on the side of the bottom. In the microchannel reactor, the materials are first mixed in the premixed pipe and then passed through the packing layer. The materials are divided again by the small channels formed by the 400μm gaps in the packing layer, so that the two materials can fully contact each other and react. The reaction pressure is controlled at 10 bar and the temperature is controlled at 90℃. The two materials react fully through the small channels. The reaction product mainly consists of difluorosulfonyl imide acid, lithium difluorosulfonyl imide, hydrogen chloride and anhydrous hydrogen fluoride. The reaction product from the reactor is depressurized to 60 kPa. Hydrogen chloride and some hydrogen fluoride escape as gases. After condensation, the hydrogen fluoride is recovered and enters the dissolution tank. The liquid enters the crystallization tank and is cooled by the coil. The resulting liquid-solid mixture is filtered to obtain lithium difluorosulfonyl imide. The filtrate is recycled to the previous process. The yield of lithium difluorosulfonyl imide is 78.4% and the recycling yield is 94%.

[0030] Example 2

[0031] The preparation of lithium bis(fluorosulfonyl)imide using a microchannel tower reactor follows these steps: (1) Add 10kg lithium fluoride and 100kg anhydrous hydrogen fluoride to the dissolving tank and stir to dissolve. In order to maintain continuity, two dissolving tanks can be used alternately. The liquid is pressurized to 10 bar by a pump and indirectly heated to 50°C by heat transfer oil. This raw material is called material A. (2) 100 kg of dichlorosulfonyl imide acid is pressurized to 10 bar by a pump, and the circulating liquid from the subsequent process is also pressurized to 10 bar by a pump. The two are mixed in a self-cleaning static mixer with a gradually expanding flow channel. After being mixed by a micro-tilt spiral blade structure, it is indirectly heated to 100°C by heat transfer oil. This stream is called material B. (3) Material A enters the reactor from inlet 1 at the bottom of the reactor, and material B enters the reactor from inlet 2 on the side of the bottom. In the microchannel reactor, the materials are first mixed in the premixed pipe and then passed through the packing layer. The materials are divided again by the small channels formed by the 400μm gaps in the packing layer, so that the two materials can fully contact each other and react. The reaction pressure is controlled at 10 bar and the temperature is controlled at 100℃. The two materials react fully through the small channels. The reaction product mainly consists of difluorosulfonyl imide acid, lithium difluorosulfonyl imide, hydrogen chloride and anhydrous hydrogen fluoride. The reaction product from the reactor is depressurized to 60 kPa. Hydrogen chloride and some hydrogen fluoride escape as gases. After condensation, the hydrogen fluoride is recovered and enters the dissolution tank. The liquid enters the crystallization tank and is cooled by the coil. The resulting liquid-solid mixture is filtered to obtain lithium difluorosulfonyl imide. The filtrate is recycled to the previous process. The yield of lithium difluorosulfonyl imide is 80.5% and the recycling yield is 94.8%.

[0032] Example 3

[0033] The preparation of lithium bis(fluorosulfonyl)imide using a microchannel tower reactor follows these steps: (1) Add 10kg lithium fluoride and 120kg anhydrous hydrogen fluoride to the dissolving tank and stir to dissolve. In order to maintain continuity, two dissolving tanks can be used alternately. The liquid is pressurized to 11 bar by a pump and indirectly heated to 50°C by heat transfer oil. This raw material is called material A. (2) 100 kg of dichlorosulfonyl imide acid is pressurized to 11 bar by a pump, and the circulating liquid from the subsequent process is also pressurized to 10 bar by a pump. The two are mixed in a self-cleaning static mixer with a gradually expanding flow channel. After being mixed by a micro-tilt spiral blade structure, it is indirectly heated to 100°C by heat transfer oil. This stream is called material B. (3) Material A enters the reactor from inlet 1 at the bottom of the reactor, and material B enters the reactor from inlet 2 on the side of the bottom. In the microchannel reactor, the materials are first mixed in the premixed pipe and then passed through the packing layer. The materials are divided again by the small channels formed by the 400μm gaps in the packing layer, so that the two materials can fully contact each other and react. The reaction pressure is controlled at 10 bar and the temperature is controlled at 100℃. The two materials react fully through the small channels. The reaction product mainly consists of difluorosulfonyl imide acid, lithium difluorosulfonyl imide, hydrogen chloride and anhydrous hydrogen fluoride. The reaction product from the reactor is depressurized to 60 kPa. Hydrogen chloride and some hydrogen fluoride escape as gases. After condensation, the hydrogen fluoride is recovered and enters the dissolution tank. The liquid enters the crystallization tank and is cooled by the coil. The resulting liquid-solid mixture is filtered to obtain lithium difluorosulfonyl imide. The filtrate is recycled to the previous process. The yield of lithium difluorosulfonyl imide is 81.2% and the recycling yield is 95.2%.

[0034] Comparative Example 1 50g of dichlorosulfonylimide, 5g of lithium fluoride and 12g of anhydrous hydrogen fluoride were added to a closed reactor. No reaction was carried out at room temperature and pressure. The temperature was gradually increased to 80℃ to start the reaction. The reaction rate was slow, the pressure changed, and the reaction time was long, about 36h. The yield of lithium dichlorosulfonylimide was 65.2%.

[0035] Comparative Example 2 50g of dichlorosulfonylimide, 5g of lithium fluoride and 12g of anhydrous hydrogen fluoride were added to a closed reactor. The pressure in the reactor was increased to 10 bar and heated to 100°C for 28 min. The yield of lithium dichlorosulfonylimide was 68%.

[0036] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing bis(fluorosulfonyl)imide salts using a microchannel tower reactor, characterized in that, Includes the following steps: S1, Dissolve alkali metal fluoride in anhydrous hydrogen fluoride to obtain mixture A; Heat and pressurize mixture A to obtain material A; S2, mix dichlorosulfonyl imide acid with circulating liquid to obtain mixture B; heat and pressurize dichlorosulfonyl imide acid or mixture B to obtain material B; S3, add material A from S1 and material B from S2 into the microchannel tower reactor from the bottom, and obtain the reaction solution after heating and pressurizing. The reaction liquids described in S4 and S3 are depressurized to obtain gas and liquid; the hydrogen fluoride in the gas is condensed and recovered and then recycled to S1 as a raw material for reuse; the liquid is cooled, crystallized, and filtered to obtain bis(fluorosulfonyl)imide salt and filtrate; the filtrate is recycled to S2 as a circulating liquid for reuse.

2. The method for preparing bis(fluorosulfonyl)imide salt using a microchannel tower reactor according to claim 1, characterized in that, The mixture A described in S1 is prepared at a temperature of 0~10℃ and a pressure of atmospheric pressure; the mixture A is heated to 40~50℃ and pressurized to 7~11 bar to obtain material A.

3. The method for preparing bis(fluorosulfonyl)imide salt using a microchannel tower reactor according to claim 1, characterized in that, In step S2, the dichlorosulfonyl imide acid or the mixture B is heated to 90-100°C and pressurized to 7-11 bar to obtain material B.

4. The method for preparing bis(fluorosulfonyl)imide salt using a microchannel tower reactor according to claim 1, characterized in that, The temperature for the heating and pressurizing reaction described in S3 is 90~100℃, the pressure is 7~11 bar, and the reaction time is 20~30 min.

5. The method for preparing bis(fluorosulfonyl)imide salt using a microchannel tower reactor according to claim 1, characterized in that, The microchannel tower reactor described in S3 is equipped with a premixing pipe and a packing layer. The packing layer includes a packing support and packing material. The packing support is used to disperse and support the packing material. The gaps between the packing material form microchannels with a size of 300~600μm. Material A and material B are added to the microchannel tower reactor from the bottom and first enter the premixing pipe for premixing. After premixing, they flow out of the premixing pipe and are divided by the microchannels before reacting.

6. The method for preparing bis(fluorosulfonyl)imide salt using a microchannel tower reactor according to claim 1, characterized in that, In step S4, the reaction solution is depressurized to 55-65 kPa to obtain gas and liquid; the cooling crystallization is performed by intermittent ultrasonic cooling crystallization at a temperature of 30-50°C.

7. The method for preparing bis(fluorosulfonyl)imide salt using a microchannel tower reactor according to claim 1, characterized in that, The molar ratio of the dichlorosulfonylimine, anhydrous hydrogen fluoride, and alkali metal fluoride is 1:(5~15):(0.7~0.9).

8. The method for preparing bis(fluorosulfonyl)imide salt using a microchannel tower reactor according to claim 1, characterized in that, The alkali metal fluoride includes lithium fluoride, sodium fluoride, or potassium fluoride; the difluorosulfonyl imide salt includes lithium difluorosulfonyl imide, sodium difluorosulfonyl imide, or potassium difluorosulfonyl imide.

9. A method for preparing difluorosulfonyl imide acid using a microchannel tower reactor, characterized in that, First, anhydrous hydrogen fluoride is heated and pressurized to obtain material A; then, the same steps as steps S2 to S4 in the method for preparing difluorosulfonyl imide salt using a microchannel tower reactor as described in any one of claims 1-6 are used to prepare difluorosulfonyl imide acid.

10. The method for preparing bisfluorosulfonyl imide acid using a microchannel tower reactor according to claim 9, characterized in that, The molar ratio of the reaction between the dichlorosulfonylimide acid and anhydrous hydrogen fluoride is 1:(2~4).

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