Preparation method of difluoromethanesulfonimide

Abstract

The present invention belongs to the technical field of the preparation of bis(fluorosulfonyl)imide, and specifically relates to a preparation method of bis(fluorosulfonyl)imide. The method comprises the following steps: (1) adding sulfuryl chloride and hydrogen fluoride into a reactor for reaction to obtain sulfuryl chloride fluoride; (2) adding a solvent into the sulfuryl chloride fluoride obtained in step (1), stirring, and then introducing ammonia gas for reaction to obtain bis(fluorosulfonyl)imide; after the reactions in step (1) and step (2) are completed, a step of by-product treatment is further included, and the method for by-product treatment is: introducing a gas to carry out the by-product out. The preparation method of bis(fluorosulfonyl)imide has low cost, simple process steps, small harm, considerable yield, high purity, avoids unnecessary toxic compounds, and is suitable for industrial production; the yield of the target product bis(fluorosulfonyl)imide is ≥95%, and the purity is ≥98%.

Description

Technical Field

[0001] The present invention belongs to the technical field of the preparation of bis(fluorosulfonyl)imide, and particularly relates to a preparation method of bis(fluorosulfonyl)imide. Background Art

[0002] Bis(fluorosulfonyl)imide has the English name bis(fluorosulfonyl)imide, abbreviated as HFSI, with the chemical formula HN(SO2F)2. It is a colorless liquid with a melting point of 17°C, a boiling point of 170°C, a density of 1.892 g / mL, and a pKa value of 1.28 in an aqueous solution at 25°C. It is an inorganic Bronsted acid. It is mainly used for the preparation of various inorganic substances containing bis(fluorosulfonyl)imide ions, such as potassium bis(fluorosulfonyl)imide, lithium bis(fluorosulfonyl)imide, silver bis(fluorosulfonyl)imide, etc., and is also widely used in the preparation of various organic liquid substances containing bis(fluorosulfonyl)imide ions.

[0003] At present, bis(fluorosulfonyl)imide in industry is generally prepared by fluorination of bis(chlorosulfonyl)imide. The preparation process of bis(chlorosulfonyl)imide mainly includes: (1) reacting phosphorus pentachloride, sulfamic acid and chlorosulfonic acid; (2) reacting sulfamic acid, thionyl chloride and chlorosulfonic acid. The fluorination reagents mainly include arsenic trifluoride, antimony trifluoride, zinc fluoride, anhydrous hydrogen fluoride, bismuth trifluoride, etc. Patent CN104918931A discloses a preparation method of bis(fluorosulfonyl)imide by reacting sulfonyl fluoride and ammonia as ammonium salts or gases. However, these methods have problems such as low yield, difficult removal of generated by-products, dangerous and corrosive intermediates, and high cost of sulfuryl fluoride, and are not suitable for industrial-scale production. Patent CN115974013A discloses a preparation method of bis(fluorosulfonyl)imide, which includes the following steps: (1) reacting sulfonyl chloride with NH3 to obtain bis(chlorosulfonyl)imide, and the pressure of the reaction is ≥0.7 MPa; (2) reacting the bis(chlorosulfonyl)imide with HF to obtain bis(fluorosulfonyl)imide. However, the by-product NH4Cl generated in step (1) of this method is a solid, and it needs to be separated by a subsequent solid-liquid separation method, which is difficult to separate and difficult to achieve continuous production.

[0004] In the currently disclosed synthesis methods, there are disadvantages such as difficult separation of bis(fluorosulfonyl)imide (HFSI) and its organic or inorganic substances containing bis(fluorosulfonyl)imide ions, low product yield, and difficulty in achieving the purity required for market production applications. In addition, the production cost is high, the requirements for reaction time and reaction temperature are harsh, strong corrosive intermediates are generated, or a large amount of toxic compounds need to be used, which is not suitable for large-scale production. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a preparation method of bis(fluorosulfonyl)imide. The preparation method has low cost, simple post-treatment, little harm in the reaction process and high purity, and is suitable for industrial production.

[0006] The preparation method of the difluoromethanesulfonimide includes the following steps:

[0007] (1) Sulfuryl chloride and hydrogen fluoride are added to a reactor for reaction to obtain sulfuryl chloride fluoride and hydrogen chloride;

[0008] The reaction equation is as follows:

[0009]

[0010] (2) A solvent is added to the sulfuryl chloride fluoride obtained in step (1), stirred, and then ammonia gas is introduced for reaction to obtain difluoromethanesulfonimide;

[0011] The reaction equation is as follows:

[0012]

[0013] After the reaction in step (2) is completed, it also includes a by-product treatment step. The method of by-product treatment is: introducing a gas to carry out hydrogen chloride and unreacted ammonia gas.

[0014] The difluoromethanesulfonimide obtained in step (2) also undergoes a purification step. The purification method includes distillation or rectification.

[0015] The specific preparation method in step (1) is: adding sulfuryl chloride and hydrogen fluoride to a reactor, under a relatively high pressure (for example, under the self-pressure of an autoclave), sulfuryl chloride fluoride (SO2ClF) and hydrogen chloride are generated. After the reaction is completed, a gas is introduced to carry out the generated hydrogen chloride.

[0016] The reaction temperature in step (1) is 70 - 150 °C, preferably 90 - 140 °C; the reaction time is 3 - 12 h; the reaction pressure is 0.1 - 1.0 MPa, preferably 0.5 MPa.

[0017] The molar ratio of sulfuryl chloride to hydrogen fluoride in step (1) is 1:(1 - 3), preferably 1:(1.5 - 2.5).

[0018] The solvent in step (2) is one or more of acetonitrile, tetrahydrofuran, acetone, ethyl acetate, 1,4-dioxane, or ethylene glycol dimethyl ether.

[0019] The molar ratio of sulfuryl chloride fluoride to ammonia gas in step (2) is 1:(4 - 8).

[0020] When adding the solvent in step (2), the system temperature is 10 - 15 °C, the reaction temperature is 10 - 35 °C, and the reaction time is 16 - 24 h.

[0021] The stirring rate in step (2) is 400-1200 rpm, preferably 960 rpm, and the stirring rate is 70%-85% of the maximum stirring rate of the reaction device.

[0022] The gas in step (3) is nitrogen or argon.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The preparation method of the bisfluorosulfonyl imide disclosed by the present invention has low cost, simple process steps, low hazards, considerable yield, and high purity, avoids unnecessary toxic compounds, thereby reducing risks and hazards in the production process, and is suitable for industrial production. The yield of the obtained target product bisfluorosulfonyl imide is ≥95%, and the purity is ≥98%. DETAILED DESCRIPTION

[0025] The present invention will be further described below with reference to the examples. Unless otherwise specified, the raw materials used in the examples are all commercially available conventional raw materials.

[0026] Example 1

[0027] (1) Add sulfuryl chloride (0.6 mol, 80.982 g) to a 500 ml autoclave, then slowly add hydrogen fluoride (1.2 mol, 24.012 g) via a pump. Maintain the reaction temperature at 120°C for 8 h at a pressure of 0.5 MPa to obtain sulfuryl chloride fluoride. This product can be directly processed into the next step without further treatment.

[0028] (2) The temperature of the autoclave was lowered to 10°C, acetonitrile solvent was added, the stirring rate was set to 80% of the maximum value, and the stirring rate was 960 rpm. Ammonia gas (2.4 mol, 40.872 g) was introduced at a constant rate over 3 hours. The temperature was then slowly raised to 24±1°C and kept for 15 hours. After the reaction was completed, a transparent light yellow liquid product, i.e., crude bis(fluorosulfonyl)imide, was obtained. After the reaction was completed, nitrogen gas was introduced to remove the hydrogen chloride and unreacted ammonia.

[0029] (3) The purification steps are as follows: Transfer the product into a rotary evaporator through an immersion tube, and wash the autoclave with acetonitrile. The washing solution obtained after washing is also transferred into the rotary evaporator through the immersion tube. The product and the washing solution are mixed at 60 °C to obtain a viscous liquid. The viscous liquid is added to a tetrabutylammonium bromide solution at a constant rate within 14 minutes, and stirred for 20 min to obtain a solid. The temperature of the tetrabutylammonium bromide solution is 31 °C, the mass of the tetrabutylammonium bromide solution is 500 g, and the mass fraction of tetrabutylammonium bromide is 35%. The obtained solid is collected by suction filtration, compressed with a rubber dam, placed in 500 g of methanol at 31 °C, cooled to -20 °C for crystallization. The crystallized product is collected by filtration, rinsed twice with methanol, and dried to a constant weight in vacuo at 45 °C to obtain the product, namely bis(fluorosulfonyl)imide, with a yield of 98% and a purity of 98%.

[0030] Example 2

[0031] (1) Add thionyl chloride (0.6 mol, 80.982 g) to a 500 ml autoclave, and then slowly add hydrogen fluoride (1.2 mol, 24.012 g) through a pump. Keep the reaction at 70 °C for 12 h, and the reaction pressure is 1.0 MPa to obtain thionyl chloride fluoride. Without treatment, directly proceed to the next step.

[0032] (2) Lower the temperature of the autoclave to 10 °C, add an acetonitrile solvent, set the stirring rate to 80% of the maximum value, the stirring rate is 960 rpm, and introduce ammonia gas (3.6 mol, 61.308 g) at a constant rate within 3 h. Then slowly raise the temperature to 24 ± 1 °C and keep the reaction for 17 h. After the reaction is completed, a transparent light yellow liquid product, namely the crude bis(fluorosulfonyl)imide, is obtained. After the reaction is completed, nitrogen gas is introduced to carry out hydrogen chloride and unreacted ammonia gas.

[0033] (3) The purification steps are as follows: Transfer the product into a rotary evaporator through an immersion tube, and wash the autoclave with acetonitrile. The washing solution obtained after washing is also transferred into the rotary evaporator through the immersion tube. The product and the washing solution are mixed at 60 °C to obtain a viscous liquid. The viscous liquid is added to a tetrabutylammonium bromide solution at a constant rate within 14 minutes, and stirred for 20 min to obtain a solid. The temperature of the tetrabutylammonium bromide solution is 31 °C, the mass of the tetrabutylammonium bromide solution is 500 g, and the mass fraction of tetrabutylammonium bromide is 35%. The obtained solid is collected by suction filtration, compressed with a rubber dam, placed in 500 g of methanol at 31 °C, cooled to -20 °C for crystallization. The crystallized product is collected by filtration, rinsed twice with methanol, and dried to a constant weight in vacuo at 45 °C to obtain the product, namely bis(fluorosulfonyl)imide, with a yield of 93% and a purity of 96%.

[0034] Example 3

[0035] (1) Add sulfuryl chloride (0.6 mol, 80.982 g) to a 500 ml autoclave, and then slowly add hydrogen fluoride (1.2 mol, 24.012 g) through a pump. React at 150 °C for 6 h under a reaction pressure of 0.5 MPa to obtain sulfuryl chloride fluoride. Without treatment, directly proceed to the next step.

[0036] (2) Cool the temperature of the autoclave to 10 °C, add acetonitrile solvent, set the stirring rate to 80% of the maximum value, with a stirring rate of 960 rpm, and introduce ammonia gas (4.8 mol, 81.744 g) at a constant rate within 5 h. Then slowly raise the temperature to 25 ± 5 °C and keep the reaction for 15 h. After the reaction is completed, a transparent light yellow liquid product, i.e., crude bis(fluorosulfonyl)imide, is obtained. After the reaction is completed, introduce nitrogen gas to carry out hydrogen chloride and unreacted ammonia gas.

[0037] (3) The purification steps are as follows: Transfer the product to a rotary evaporator through an immersion tube, and wash the autoclave with acetonitrile. The washing solution obtained after washing is also transferred to the rotary evaporator through the immersion tube. The product and the washing solution are mixed at 60 °C to obtain a viscous liquid. The viscous liquid is added to a tetrabutylammonium bromide solution at a constant rate within 14 minutes and stirred for 20 min to obtain a solid. The temperature of the tetrabutylammonium bromide solution is 31 °C, the mass of the tetrabutylammonium bromide solution is 500 g, and the mass fraction of tetrabutylammonium bromide is 40%. The obtained solid is collected by suction filtration, compressed with a rubber dam, placed in 500 g of methanol at 31 °C, cooled to -20 °C for crystallization, the crystalline product is collected by filtration, rinsed twice with methanol, and dried to a constant weight in vacuo at 45 °C to obtain the product, i.e., bis(fluorosulfonyl)imide, with a yield of 92% and a purity of 97%.

[0038] Example 4

[0039] (1) Add sulfuryl chloride (0.6 mol, 80.982 g) to a 500 ml autoclave, and then slowly add hydrogen fluoride (1.2 mol, 24.012 g) through a pump. React at 110 °C for 8 h under a reaction pressure of 0.5 MPa to obtain sulfuryl chloride fluoride. Without treatment, directly proceed to the next step.

[0040] (2) Cool the temperature of the autoclave to 10 °C, add acetonitrile solvent, set the stirring rate to 80% of the maximum value, with a stirring rate of 1100 rpm, and introduce ammonia gas (4.8 mol, 81.744 g) at a constant rate within 5 h. Then slowly raise the temperature to 24 ± 1 °C and keep the reaction for 15 h. After the reaction is completed, a transparent light yellow liquid product, i.e., crude bis(fluorosulfonyl)imide, is obtained. After the reaction is completed, introduce nitrogen gas to carry out hydrogen chloride and unreacted ammonia gas.

[0041] (3) The purification steps are as follows: Transfer the product to a rotary evaporator through an immersion tube, and wash the autoclave with acetonitrile. The washing liquid obtained after washing is also transferred to the rotary evaporator through the immersion tube. The product and the washing liquid are mixed at 60 °C to obtain a viscous liquid. The viscous liquid is added to a tetrabutylammonium bromide solution at a constant rate within 14 minutes and stirred for 20 min to obtain a solid. The temperature of the tetrabutylammonium bromide solution is 31 °C, the mass of the tetrabutylammonium bromide solution is 500 g, and the mass fraction of tetrabutylammonium bromide is 35%. The obtained solid is collected by suction filtration, compressed with a rubber dam, placed in 500 g of methanol at 31 °C, cooled to -20 °C for crystallization, the crystalline product is collected by filtration, rinsed twice with methanol, and dried to a constant weight in vacuo at 45 °C to obtain the product, namely bis(fluorosulfonyl)imide, with a yield of 97% and a purity of 98%.

[0042] Example 5

[0043] (1) Add thionyl chloride (0.6 mol, 80.982 g) to a 500 ml autoclave, and then slowly add hydrogen fluoride (1.5 mol, 30.015 g) through a pump. React at 110 °C for 8 h, and the reaction pressure is 0.5 MPa to obtain thionyl chloride fluoride. Without treatment, directly proceed to the next step.

[0044] (2) Cool the temperature of the autoclave to 10 °C, add an acetonitrile solvent, set the stirring rate to 80% of the maximum value, the stirring rate is 800 rpm, and introduce ammonia gas (4.8 mol, 81.744 g) at a constant rate within 5 h, then slowly raise the temperature to 24 ± 1 °C and keep the temperature for reaction for 18 h. After the reaction is completed, a transparent light yellow liquid product, namely the crude bis(fluorosulfonyl)imide, is obtained. After the reaction is completed, nitrogen gas is introduced to carry out hydrogen chloride and unreacted ammonia gas.

[0045] (3) The purification steps are as follows: Transfer the product to a rotary evaporator through an immersion tube, and wash the autoclave with acetonitrile. The washing liquid obtained after washing is also transferred to the rotary evaporator through the immersion tube. The product and the washing liquid are mixed at 60 °C to obtain a viscous liquid. The viscous liquid is added to a tetrabutylammonium bromide solution at a constant rate within 14 minutes and stirred for 20 min to obtain a solid. The temperature of the tetrabutylammonium bromide solution is 31 °C, the mass of the tetrabutylammonium bromide solution is 500 g, and the mass fraction of tetrabutylammonium bromide is 35%. The obtained solid is collected by suction filtration, compressed with a rubber dam, placed in 500 g of methanol at 31 °C, cooled to -20 °C for crystallization, the crystalline product is collected by filtration, rinsed twice with methanol, and dried to a constant weight in vacuo at 45 °C to obtain the product, namely bis(fluorosulfonyl)imide, with a yield of 95% and a purity of 98%.

[0046] Comparative Example 1

[0047] Lower the temperature of a 500 ml autoclave to 10 °C, add acetonitrile solvent, add sulfuryl fluoride (0.6 mol, 61.282 g) to the autoclave, set the stirring rate to 80% of the maximum value, with the stirring rate being 960 rpm, and introduce ammonia gas (2.4 mol, 40.872 g) at a constant rate within 3 h. Then slowly raise the temperature to 24 ± 1 °C and keep the reaction at this temperature for 15 h. After the reaction is completed, introduce nitrogen gas to carry out the unreacted ammonia and sulfuryl fluoride, and a pale yellow solid-liquid mixture is obtained. It is detected that no bis(fluorosulfonyl)imide is generated.

[0048] Comparative Example 2

[0049] Lower the temperature of a 500 ml autoclave to 10 °C, add acetonitrile solvent, add thionyl chloride (0.6 mol, 80.982 g) to the autoclave, set the stirring rate to 80% of the maximum value, with the stirring rate being 960 rpm, and introduce ammonia gas (2.4 mol, 40.872 g) at a constant rate within 3 h. Then slowly raise the temperature to 24 ± 1 °C and keep the reaction at this temperature for 15 h. After the reaction is completed, introduce nitrogen gas to carry out the unreacted ammonia. Then slowly add hydrogen fluoride (1.5 mol, 30.015 g) through a pump and keep the reaction at 110 °C for 8 h, with the reaction pressure being 0.5 MPa. After the reaction is completed, introduce a gas to carry out the hydrogen fluoride, and a light yellow solid-liquid mixture is obtained. It is detected that no bis(fluorosulfonyl)imide is generated.

Claims

1. A preparation method of difluoromethanesulfonimide, characterized in that: It includes the following steps: (1) Add sulfonyl chloride and hydrogen fluoride into a reactor for reaction to obtain sulfuryl chloride fluoride and hydrogen chloride; The reaction equation is as follows: ； (2) Add a solvent to the sulfuryl chloride fluoride obtained in step (1), stir, and then introduce ammonia gas for reaction to obtain bis(fluorosulfonyl)imide; The reaction equation is as follows: ； The bis(fluorosulfonyl)imide obtained in step (2) also undergoes a purification step, and the purification method includes distillation or rectification.

2. The preparation method of difluoromethanesulfonimide according to claim 1, wherein: After the reaction in step (2) is completed, it also includes a by-product treatment step, and the by-product treatment method is: introduce a gas to carry out hydrogen chloride and unreacted ammonia gas.

3. The preparation method of difluoromethanesulfonimide according to any one of claims 1-2, characterized in that: In step (1), the reaction temperature is 70 - 150 °C, the reaction pressure is 0.1 - 1.0 MPa, and the reaction time is 3 - 12 h.

4. The preparation method of difluoromethanesulfonimide according to any one of claims 1-2, characterized in that: In step (1), the molar ratio of sulfonyl chloride to hydrogen fluoride is 1:(1 - 3).

5. The preparation method of difluoromethanesulfonimide according to any one of claims 1-2, characterized in that: In step (2), the solvent is one or more of acetonitrile, tetrahydrofuran, acetone, ethyl acetate, 1,4-dioxane, or ethylene glycol dimethyl ether.

6. The preparation method of the difluoromethanesulfonimide according to any one of claims 1-2, characterized in that: In step (2), the molar ratio of sulfuryl chloride fluoride to ammonia gas is 1:(4 - 8).

7. The preparation method of difluoromethanesulfonimide according to any one of claims 1-2, characterized in that: In step (2), the reaction temperature is 10 - 35 °C, and the reaction time is 16 - 24 h.

8. The preparation method of difluoromethanesulfonimide according to any one of claims 1-2, characterized in that: In step (2), the stirring rate is 400 - 1200 rpm.

9. The preparation method of the difluoromethanesulfonimide according to claim 2, characterized in that: The gas is one of nitrogen or argon.

Images