CN-122010064-A - Method for preparing organic alkali salt of difluoro-sulfonyl imide

CN122010064ACN 122010064 ACN122010064 ACN 122010064ACN-122010064-A

Abstract

The invention discloses a method for preparing organic alkali salt of difluoro sulfonyl imide, which comprises the following steps of (a) adding a solvent into a reactor, then adding organic alkali, inorganic alkaline substances and a phase transfer catalyst, (b) controlling the reaction temperature, simultaneously introducing sulfuryl fluoride and ammonia gas into the reactor, preserving heat after ventilation is finished, (c) filtering to obtain solid fluoride salt and filtrate, and (d) concentrating the filtrate, and washing the obtained concentrate with water to obtain the organic alkali salt of difluoro sulfonyl imide. The invention has the advantages that under the action of the phase transfer catalyst, inorganic alkaline substances can react with organic alkali hydrofluoric acid salt to generate solid fluoride salt, and meanwhile, organic alkali is dissociated, so that the reaction selectivity is ensured, the consumption of the organic alkali is greatly reduced, the operation is simple, and the industrial implementation is convenient.

Inventors

YUAN SHENFENG
LIU CHENGFENG
JIANG QINGLONG
ZHOU KAI

Assignees

临海市利民化工有限公司

Dates

Publication Date: 20260512
Application Date: 20260203

Claims (10)

1.A method for preparing organic alkali salt of difluoro sulfonyl imide is characterized by comprising the following steps of (a) adding a solvent into a reactor, then adding organic alkali, inorganic alkaline substances and a phase transfer catalyst, reducing the temperature of materials in the reactor to be not higher than 10 ℃, b) controlling the reaction temperature to be not higher than 10 ℃, simultaneously introducing sulfuryl fluoride and ammonia gas into the reactor under stirring, preserving heat for 0.5-3 hours after the ventilation is finished, C) filtering to obtain solid fluoride salt and filtrate, d) controlling the temperature to be not higher than 50 ℃, concentrating the filtrate, and washing the obtained concentrate to obtain the target product of organic alkali salt of difluoro sulfonyl imide.
2. The method for preparing organic base salt of bis (fluorosulfonyl) imide according to claim 1, wherein the solvent in the step (a) is one or more of toluene, tetrahydrofuran, acetonitrile and methyl tert-butyl ether, the organic base is one of trimethylamine, triethylamine, diisopropylethylamine or tri-n-propylamine, and the addition weight of the organic base is 5% -25% of the weight of the solvent.
3. The method for preparing organic alkali salt of difluoro-sulfonyl imide according to claim 1, wherein in step (a), the inorganic alkaline substance is one or more of calcium oxide, lithium carbonate, sodium carbonate and potassium carbonate, the molar ratio of the inorganic alkaline substance to the organic alkali is 1.0-3.0:1, and the inorganic alkaline substance is added into the reactor in a one-time or batch mode.
4. The method for preparing organic alkali salt of bis (fluorosulfonyl) imide according to claim 1, wherein the phase transfer catalyst in the step (a) is polyethylene glycol or crown ether, and the addition weight of the phase transfer catalyst is 0.01% -0.5% of the weight of the solvent.
5. The method for preparing organic base salts of bis-fluorosulfonyl imide according to claim 4, wherein the polyethylene glycol is one or more of polyethylene glycol-400, polyethylene glycol-600, polyethylene glycol-800, and the crown ether is one or more of 18-crown ether-6 or 15-crown ether-5.
6. The method for preparing organic alkali salt of difluoro sulfonyl imide according to claim 1, wherein the molar ratio of sulfuryl fluoride to ammonia gas in step (b) is 1.8-2.2:1, the time of introducing sulfuryl fluoride to ammonia gas is 0.5-6 hours, and the molar ratio of sulfuryl fluoride introduced in step (b) to organic alkali added in step (a) is 1.0-2.0:1.
7. The process for preparing organic base salts of bis-fluorosulfonyl imides according to claim 1, wherein the temperature in steps (a) and (b) is-15 to 10 ℃.
8. The process for preparing organic base salts of bis-fluorosulfonyl imide according to claim 1 wherein the filtration in step (c) is one of suction filtration, pressure filtration or centrifugal filtration.
9. The method for preparing organic alkali salt of bis (fluorosulfonyl) imide according to claim 1, wherein in the step (d), the concentration is performed by vacuum evaporation concentration, the temperature of the vacuum evaporation concentration is 15-50 ℃, and the vacuum degree is-0.1-0.08 MPa.
10. The method for preparing organic alkali salt of bis (fluorosulfonyl) imide according to claim 1, wherein the temperature of the water washing in the step (d) is 5-20 ℃, the water consumption is 0.2-1.0 times of the weight of the concentrate, the water washing mode is multi-stage cross flow or countercurrent, and the water washing times are 1-4 times.

Description

Method for preparing organic alkali salt of difluoro-sulfonyl imide Technical Field The invention belongs to the technical field of chemical synthesis, and relates to a method for preparing organic alkali salt of difluoro sulfimide. Background Lithium bis (fluorosulfonyl imide), abbreviated as LiFSI, is a white powdery solid with good thermal stability, is a key base material for lithium ion battery electrolytes, and is considered to be one of the most likely lithium salts to replace lithium hexafluorophosphate. The electrolyte has better conductivity than lithium hexafluorophosphate, has good compatibility with graphite, silicon negative electrode and lithium iron phosphate positive electrode, can improve the cycle and rate capability of the battery, can improve the discharge performance in a low-temperature environment, and can maintain the capacitance retention rate at high temperature. Lithium bis (fluorosulfonyl) imide can be prepared by reacting an organic base salt of bis (fluorosulfonyl) imide with a lithium source. The organic base salt of the bis-fluorosulfonyl imide can be prepared by reacting sulfuryl fluoride with ammonia in the presence of an organic base. For example, chinese patent CN102378755A discloses a method for preparing bis-fluorosulfonyl imide triethylamine salt, which uses sulfuryl fluoride and ammonia gas as raw materials, acetonitrile as solvent, and makes reaction in the presence of triethylamine, so that the target product with purity of more than 99% can be obtained. Chinese patent CN110217764a discloses a method for preparing organic alkali salt of difluoro-sulfonyl imide, which is characterized in that ammonia reacts with sulfuryl fluoride in organic solvent in the presence of organic alkali and fluoride salt, so as to prepare organic alkali salt of difluoro-sulfonyl imide, and the fluoride salt is sodium fluoride, potassium fluoride, etc., which can effectively avoid the generation of dark impurities, improve the purity of difluoro-sulfonyl imide salt and also improve the reaction rate. Chinese patent CN116283601A uses sulfuryl fluoride and ammonium salt as reaction raw materials, and uses aprotic polar solvent and organic alkaline acid-binding agent to make them undergo the process of reaction in high-pressure reactor so as to obtain the difluoro sulfimide organic ammonium salt, and the ammonium salt is ammonium fluoride, ammonium chloride and ammonium bromide. Chinese patent CN120329199A adopts ammonia gas, sulfuryl fluoride and liquid organic alkali as reaction raw materials, and under the condition of no solvent or a small amount of solvent, the raw materials react by pressurization to generate organic alkali salt of difluoro sulfimide, so that a product with lower chromaticity can be obtained. The above-described methods for preparing organic base salts of bis-fluorosulfonyl imides are all carried out in the presence of an organic base. The organic base has two functions, namely, the organic base is combined with the difluoro sulfonimide generated by the reaction to form target product difluoro sulfonimide organic base salt, and the organic base is reacted with byproduct hydrogen fluoride generated by the reaction as an acid binding agent to generate triethylamine hydrofluoric acid salt. Since 1 mole of bis (fluorosulfonyl) imide generates 2 moles of hydrogen fluoride, 3 moles of organic base are consumed to generate 1 mole of bis (fluorosulfonyl) imide organic base salt, which is the target product, in order to ensure the selectivity of the reaction. The consumption of large amounts of organic base not only increases the cost of raw materials, but also increases the cost of subsequent treatments and recovery. Therefore, it is urgent to develop a method for preparing organic base salts of bis-fluorosulfonyl imide with low consumption of organic base. Disclosure of Invention The invention aims to overcome the defects of the prior art and provides a method for preparing organic alkali salt of difluoro sulfimide with low organic alkali consumption. The method for preparing the organic alkali salt of the difluoro sulfonyl imide comprises the following steps of (a) adding a solvent into a reactor, then adding an organic alkali, an inorganic alkaline substance and a phase transfer catalyst, reducing the temperature of materials in the reactor to be not higher than 10 ℃, b) controlling the reaction temperature to be not higher than 10 ℃, simultaneously introducing sulfuryl fluoride and ammonia gas into the reactor under stirring, preserving heat for 0.5-3 hours after the ventilation is finished, C) filtering to obtain a solid fluoride salt and a filtrate, d) controlling the temperature to be not higher than 50 ℃, concentrating the filtrate, and washing the obtained concentrate to obtain the organic alkali salt of the difluoro sulfonyl imide as a target product. According to a preferred embodiment of the present invention, the solvent in the step (a) is one or more of toluene,