Novel method for preparing lithium bis (fluorosulfonyl) imide

Abstract

The method comprises the following steps: setting the temperature of a reaction kettle to be-5 to 0 DEG C and the pressure of the reaction kettle to be 0.01 to 0.1 MPa, adding lithium fluoride and hydrogen fluoride into the reaction kettle, after the lithium fluoride is completely dissolved in the hydrogen fluoride, respectively introducing sulfuryl fluoride and ammonia gas, keeping the temperature of the reaction kettle to be-5 to 0 DEG C and the pressure of the reaction kettle to be 0.01 to 0.1 MPa, reacting for 1 to 5 hours, and after the reaction is finished, filtering, washing and drying to obtain the lithium bis (fluorosulfonyl) imide. Absorbing gaseous substances, and purifying to obtain a target product. According to the method, one-pot reaction is adopted, hydrogen fluoride is used as a reaction solvent, other solvents or catalysts are not used, chloride ions and other cations and anions do not exist, the product purity is improved, the product yield is high, the used raw materials are easy to obtain, the raw material cost is low, the preparation process is simple, the requirement for equipment is low, operation is safe, and aftertreatment is simple; the method is a green synthesis method.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of new energy materials, and particularly relates to a method for preparing lithium bisfluorosulfonylimide. BACKGROUND

[0002] With the development of science and technology, high-capacity lithium ion batteries have a broad application space. As the electrolyte material of lithium ion batteries, lithium bisfluorosulfonylimide has good thermal stability and chemical stability, and is considered by people as a new generation of lithium ion battery electrolyte that can replace lithium hexafluorophosphate. In addition, as the electrolyte of lithium ion batteries, lithium bisfluorosulfonylimide has the characteristics of long service life, high safety, and environmental friendliness in addition to good stability.

[0003] At present, the methods for preparing lithium bisfluorosulfonylimide at home and abroad mainly include the following steps: first, fluorination of bischlorosulfonylimide to synthesize bisfluorosulfonylimide, and then reaction of bisfluorosulfonylimide with a metal lithium salt to prepare the corresponding lithium salt.

[0004] For example, CN115893337A patent reports that bischlorosulfonylimide is prepared by reaction of aminosulfonic acid, chlorosulfonic acid and thionyl chloride, and then bisfluorosulfonylimide is prepared by reaction of bischlorosulfonylimide with hydrogen fluoride, and lithium bisfluorosulfonylimide is prepared by reaction of bisfluorosulfonylimide with lithium fluoride.

[0005] At the same time, US20120245386A1 and US20140142338A1 patents use SO2F2 and NH3 as raw materials, organic amine as catalyst, and acetonitrile as solvent to prepare bisfluorosulfonylimide. WO2010113835A1 patent also reports that bisfluorosulfonylimide is prepared by reaction of SO2F2, NH3 and Et3N, and bisfluorosulfonylimide can be further reacted with a lithium salt to prepare lithium bisfluorosulfonylimide. However, in the above reaction, triethylamine can promote SO2F2 to generate hydrolysis product triethylamine fluoride and other by-products, resulting in increased purification processing cost.

[0006] Therefore, developing a new method for synthesizing lithium bisfluorosulfonylimide is still an important research direction for current sustainable development. SUMMARY

[0007] The technical problem to be solved by the present application is to provide a new method for preparing lithium bisfluorosulfonylimide. The method uses sulfuryl fluoride, ammonia and lithium fluoride as reaction raw materials, hydrogen fluoride as reaction solvent, and adopts one-pot method to prepare lithium bisfluorosulfonylimide. The method has the advantages of simple process, safe operation, high yield, simple post-treatment and the like.

[0008] To solve the above technical problems, the present application discloses a new method for preparing lithium bisfluorosulfonylimide, comprising the following steps:

[0009] The temperature of the reaction kettle is set to -5~0℃, the pressure is 0.01~0.1 MPa, lithium fluoride and hydrogen fluoride are added into the reaction kettle, after the lithium fluoride is completely dissolved in the hydrogen fluoride, sulfuryl fluoride and ammonia gas are respectively introduced, the temperature of the reaction kettle is kept at -5~0℃, the pressure is kept at 0.01~0.1 MPa, the reaction is carried out for 1~5 hours, after the reaction is completed, the gaseous substances (unreacted sulfuryl fluoride and ammonia gas and vaporized hydrogen fluoride) in the reaction kettle are introduced into a gas absorption device, then nitrogen gas is used to replace the gas in the reaction system, then the reaction material is pressed out by using nitrogen gas, filtration is carried out, the filtrate is sent to another container, the filtrate is concentrated, the concentrated liquid is dissolved by using tetrahydrofuran, active carbon is added, stirring is carried out at room temperature, filtration is carried out, the active carbon and insoluble substances are removed, concentration is carried out by using a rotary evaporator, vacuum drying is carried out, and the target product is prepared.

[0010] Further, the molar ratio of the sulfuryl fluoride, ammonia gas and lithium fluoride is 1:0.5~1.5:1~3.

[0011] Further, the mass ratio of the lithium fluoride and hydrogen fluoride is 1:1~5.

[0012] The beneficial effects of the present application are as follows:

[0013] (1) The present application adopts one-pot reaction, the raw materials are easy to obtain, the preparation process is simple, the requirement for equipment is low, the operation is safe, the post-treatment is simple, and it is a green synthesis method.

[0014] (2) Hydrogen fluoride is used as a reaction solvent, no other solvent or catalyst is used, no chloride ions and other cations and anions exist, the product purity is improved, the product yield is high, and the raw material cost is low. DETAILED DESCRIPTION

[0015] The present application will be further explained by combining with the following examples. The following examples are only used to illustrate the present application, but not used to limit the implementation range of the present application.

[0016] Example 1

[0017] A stainless steel reactor was set to 0°C and 0.01 MPa. 26 g (1 mol) of lithium fluoride and 52 g of hydrogen fluoride were added into the reactor. After the lithium fluoride was completely dissolved in the hydrogen fluoride, 102 g (1 mol) of sulfuryl fluoride and 8.5 g (0.5 mol) of ammonia were introduced into the reactor, respectively. The temperature of the reactor was kept at 0°C and the pressure was kept at 0.01 MPa. The reaction was carried out for 1 hour. After the reaction was completed, the gas in the reactor was introduced into a gas absorption device. The reaction system was replaced with nitrogen. The reaction material was discharged by nitrogen. The filtrate was obtained by filtration. The filtrate was concentrated. The concentrated solution was dissolved in tetrahydrofuran. Activated carbon was added and stirred at room temperature for 30 minutes. The activated carbon and insoluble substances were removed by filtration. The filtrate was concentrated by a rotary evaporator and dried in vacuum to obtain 91 g of the target product in white powder with a yield of 98%. 19 F NMR (nuclear magnetic resonance, which can determine the molecular structure) (acetonitrile as solvent, monofluorotrichloromethane as internal standard): +52.25.

[0018] Example 2

[0019] A stainless steel reactor was set to -5°C and 0.1 MPa. 52 g (2 mol) of lithium fluoride and 52 g of hydrogen fluoride were added into the reactor. After the lithium fluoride was completely dissolved in the hydrogen fluoride, 102 g (1 mol) of sulfuryl fluoride and 17 g (1 mol) of ammonia were introduced into the reactor, respectively. The temperature of the reactor was kept at -5°C and the pressure was kept at 0.1 MPa. The reaction was carried out for 2 hours. After the reaction was completed, the gas in the reactor was introduced into a gas absorption device. The reaction system was replaced with nitrogen. The reaction material was discharged by nitrogen. The filtrate was obtained by filtration. The filtrate was concentrated. The concentrated solution was dissolved in tetrahydrofuran. Activated carbon was added and stirred at room temperature for 30 minutes. The activated carbon and insoluble substances were removed by filtration. The filtrate was concentrated by a rotary evaporator and dried in vacuum to obtain 91.3 g of the target product in white powder with a yield of 98.3%. 19 F NMR (acetonitrile as solvent, monofluorotrichloromethane as internal standard): +52.25.

[0020] Example 3

[0021] A stainless steel reactor was set at -5°C and 0.05 MPa. 78 g (3 mol) of lithium fluoride and 78 g of hydrogen fluoride were added into the reactor. After the lithium fluoride was completely dissolved in the hydrogen fluoride, 102 g (1 mol) of sulfuryl fluoride and 25.5 g (1.5 mol) of ammonia were introduced into the reactor, respectively. The temperature of the reactor was kept at -5°C and the pressure was kept at 0.05 MPa. The reaction was carried out for 3 hours. After the reaction was completed, the gas in the reactor was introduced into a gas absorption device. The reaction system was replaced with nitrogen. The reaction material was discharged by nitrogen. The filtrate was concentrated. The concentrated solution was dissolved in tetrahydrofuran. Activated carbon was added and stirred at room temperature for 30 minutes. The activated carbon and insoluble substances were removed by filtration. The filtrate was concentrated by a rotary evaporator and dried in vacuum to obtain 91.1 g of the target product in white powder with a yield of 98.1%. 19 F NMR (acetonitrile as solvent, monofluorotrichloromethane as internal standard): +52.25.

[0022] Example 4

[0023] A stainless steel reactor was set at -5°C and 0.1 MPa. 52 g (2 mol) of lithium fluoride and 104 g of hydrogen fluoride were added into the reactor. After the lithium fluoride was completely dissolved in the hydrogen fluoride, 102 g (1 mol) of sulfuryl fluoride and 17 g (1 mol) of ammonia were introduced into the reactor, respectively. The temperature of the reactor was kept at -5°C and the pressure was kept at 0.1 MPa. The reaction was carried out for 5 hours. After the reaction was completed, the gas in the reactor was introduced into a gas absorption device. The reaction system was replaced with nitrogen. The reaction material was discharged by nitrogen. The filtrate was concentrated. The concentrated solution was dissolved in tetrahydrofuran. Activated carbon was added and stirred at room temperature for 30 minutes. The activated carbon and insoluble substances were removed by filtration. The filtrate was concentrated by a rotary evaporator and dried in vacuum to obtain 91.5 g of the target product in white powder with a yield of 98.5%. 19 F NMR (acetonitrile as solvent, monofluorotrichloromethane as internal standard): +52.25.

[0024] Example 5

[0025] The temperature of a stainless steel reaction kettle is set to -5℃, and the pressure is 0.1 MPa. 52 grams (2 moles) of lithium fluoride and 260 grams of hydrogen fluoride are added into the reaction kettle. After the lithium fluoride is completely dissolved in the hydrogen fluoride, 102 grams (1 mole) of sulfuryl fluoride and 25.5 grams (1.5 moles) of ammonia gas are respectively introduced. The temperature of the reaction kettle is kept at -5℃, and the pressure is kept at 0.1 MPa. The reaction is carried out for 3 hours. After the reaction is completed, the gaseous substances in the reaction kettle are introduced into a gas absorption device. Then, the reaction system is replaced with nitrogen gas. The reaction materials are discharged by using nitrogen gas. The filtrate is sent to another container. The filtrate is concentrated. The concentrated liquid is dissolved in tetrahydrofuran. Activated carbon is added. The mixture is stirred at room temperature for 30 minutes. Filtration is carried out to remove the activated carbon and insoluble substances. Concentration is carried out by using a rotary evaporator. Vacuum drying is carried out to obtain 91.7 grams of the target product in the form of white powder, with a yield of 98.7%. 19 F NMR (acetonitrile as solvent, monofluorotrichloromethane as internal standard): +52.25.

[0026] Of course, the present application can have other various embodiments. Those skilled in the art can make various corresponding changes and modifications according to the present application without departing from the spirit and essence of the present application. These corresponding changes and modifications should all belong to the protection scope of the claims of the present application.

Claims

1. A novel method for preparing lithium bis(fluorosulfonyl)imide, characterized in that, Includes the following steps: Set the reactor temperature to -5 to 0℃ and the pressure to 0.01 to 0.1 MPa. Add lithium fluoride and hydrogen fluoride to the reactor. After the lithium fluoride is completely dissolved in the hydrogen fluoride, introduce sulfuryl fluoride and ammonia gas respectively. Maintain the reactor temperature at -5 to 0℃ and the pressure at 0.01 to 0.1 MPa for 1 to 5 hours. After the reaction is complete, absorb the gaseous substances and purify to obtain the target product.

2. The novel method for preparing lithium bis(fluorosulfonyl)imide according to claim 1, characterized in that, The molar ratio of sulfuryl fluoride, ammonia, and lithium fluoride is 1:0.5 to 1.5:1 to 3.

3. The novel method for preparing lithium bis(fluorosulfonyl)imide according to claim 1, characterized in that, The mass ratio of lithium fluoride to hydrogen fluoride is 1:1 to 5.