Preparation method of sulfuryl fluoride

Abstract

The invention discloses a preparation method of sulfuryl fluoride. The preparation method comprises the following steps: (1) grinding CaF2 and MXH3-XPO4 in a ball mill to obtain inorganic villiaumite A with fluorination activity; and (2) reacting the inorganic villiaumite A with sulfuryl chloride in a non-aqueous polar solvent. The raw materials used in the sulfuryl fluoride preparation method are cheap and easy to obtain, high-risk materials such as hydrogen fluoride or sulfur trioxide are not involved, the impurities sulfuryl fluoride chloride and sulfuryl chloride in the mixed gas can be separated through simple condensation and can be recycled through recycling, the production process is simple, the reaction temperature is low, the requirement for equipment is low, and the method is suitable for industrial production. And the prepared sulfuryl fluoride has high yield and high purity, and is suitable for industrial production.

Description

Technical Field

[0001] The invention belongs to the field of preparation of sulfuryl fluoride, and specifically relates to a method for preparing sulfuryl fluoride by taking calcium fluoride as a fluorine source. Background Art

[0002] Sulfuryl fluoride (SO2F2), an inorganic compound, is a colorless and odorless toxic gas at room temperature and pressure. It is chemically stable at high temperatures and does not decompose even at 400°C. Sulfuryl fluoride has become a widely used fumigant due to its excellent diffusion and penetration capabilities, low-temperature operation convenience, rapid desorption, and low dosage. At the same time, as a key intermediate in the field of fluorine chemical industry, its application range is constantly expanding.

[0003] In recent years, sulfuryl fluoride has been used as a key raw material for the synthesis of lithium bis(fluorosulfonyl)imide (chemical formula: Li[N(SO2F)2], abbreviated as LiFSI). LiFSI is a new fluorine-containing material with broad application prospects, mainly used as a high-performance electrolyte in lithium-ion batteries, supercapacitors and ionic liquids. Its application in lithium-ion battery electrolytes significantly improves the electrochemical stability of the battery, reduces the probability of side reactions, enhances thermal stability, and optimizes electrical conductivity, especially in the field of power batteries, which helps to improve the battery's cycle and rate performance. Therefore, the sulfuryl fluoride required to synthesize LiFSI must have high purity to ensure the quality and performance of the final product.

[0004] The methods for preparing sulfuryl fluoride reported at present include the following: US3403144A reported a method for preparing sulfuryl fluoride by reacting barium fluoride or barium fluorosilicate with sulfur trioxide at a reaction temperature of 500-650°C, and the method did not involve the identification and separation of by-products; CN114368728B reported that sulfur trioxide vapor and barium fluoride were reacted to generate a mixed gas of barium sulfate and sulfuryl fluoride, and the mixed gas was acid-washed by a concentrated sulfuric acid solution with a concentration of 70-98.3% to obtain a first-level purified sulfuryl fluoride gas, and then subjected to a series of rectification and separation processes to finally obtain high-purity sulfuryl fluoride; The method described in US7145046B2 is a method for preparing sulfuryl fluoride by adding liquid sulfuryl chloride to anhydrous hydrogen fluoride in which a catalyst has been dissolved, and a fluorination reaction occurs under stirring to generate a sulfuryl fluoride-containing gas and a mixed gas of hydrogen chloride, and then the hydrogen chloride is separated by absorbing in a falling film absorber, and then dried, compressed and condensed.

[0005] The reported methods for synthesizing sulfuryl fluoride involve high-risk materials such as hydrogen fluoride or sulfur trioxide, which usually have harsh preparation conditions, complex equipment, high operating requirements and risks, and are accompanied by high-risk light and heavy components that are difficult to separate. The cost and safety risks are high during industrial production.

[0006] Calcium fluoride (fluorite) is the source of the fluorine chemical industry, but calcium fluoride has extremely high stability and extremely poor reactivity. It is usually first prepared as a high-risk material hydrogen fluoride in concentrated sulfuric acid, and then used as a fluorine source to construct a series of fluorine-containing compounds or fluorine-containing materials.

[0007] In view of the above-mentioned technical problems in the traditional preparation of sulfuryl fluoride and the current status of the use of sulfuryl fluoride in various application fields, the art is in urgent need of a new preparation process for sulfuryl fluoride. Summary of the invention

[0008] The object of the present invention is to provide a method for preparing sulfuryl fluoride using calcium fluoride as a fluorine source. Compared with the traditional process, the raw materials are cheap and easy to obtain, the preparation conditions are mild, the equipment requirements are low, the safety risk is low, and the prepared sulfuryl fluoride has high purity and high yield.

[0009] To achieve the above object, the present invention provides the following technical solutions:

[0010] A method for preparing sulfuryl fluoride comprises the following steps:

[0011] (1) CaF2 and M X H 3-X PO4 is ground in a ball mill to obtain an inorganic fluoride salt A having fluorination activity;

[0012] (2) Inorganic fluoride salt A reacts with sulfuryl chloride in a non-aqueous polar solvent.

[0013] As a preferred solution, the step (2) further comprises: condensing sulfuryl fluoride and sulfuryl chloride in the reflux mixed gas at low temperature, and collecting sulfuryl fluoride by a gas compression pump.

[0014] Preferably, M X H 3-X The cation M in PO4 is selected from monovalent alkali metals such as lithium, cesium, sodium, and potassium.

[0015] Preferably, CaF2 and M X H 3-X The molar ratio of PO4 is 1:(2.5-5), more preferably 1:(4-5).

[0016] Preferably, CaF2 and M X H 3-X The grinding time of PO4 is 2 to 24 hours, more preferably 8 to 24 hours.

[0017] Preferably, the molar ratio of the inorganic fluoride salt A (calculated as calcium fluoride) to sulfuryl chloride is 1:(0.1-0.5), more preferably 1:(0.1-0.3).

[0018] Preferably, the reaction time of step (2) is 1 to 24 hours, and the reaction temperature is 0°C to 68°C; more preferably, the reaction time is 2 to 12 hours, and the reaction temperature is 5°C to 15°C.

[0019] Preferably, the temperature of the low-temperature condensation is -50°C to 0°C, more preferably -40°C to -20°C.

[0020] Preferably, the non-aqueous polar solvent is selected from one or more of methyl formate, ethyl formate, propyl formate, isopropyl formate, ethyl acetoacetate, n-butyl acetate, isobutyl acetate, isoamyl acetate, methyl lactate, ethyl acetate, methyl acetate, methyl tert-butyl ether, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, ethyl salicylate, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, n-hexanol, cyclohexanol, n-octanol, isooctyl alcohol, glycerol, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, tetrahydrofuran, dioxolane, propylene oxide, diethoxymethane, anisole, acetonitrile, hydroxyacetonitrile, propionitrile, butyronitrile, α-phenylbutyronitrile, isovaleronitrile, 1,3,6-hexanetrinitrile, and 1,2,4,5-benzenetetracarbonitrile.

[0021] Preferably, the mass ratio of the added non-aqueous polar solvent to CaF2 is (1-20):1, more preferably (12-18):1.

[0022] After the reaction is completed, a high-purity sulfuryl fluoride product can be obtained through a gas compressor, and the purity of the obtained sulfuryl fluoride gas is determined by gas chromatography. DETAILED DESCRIPTION

[0023] Example 1

[0024] Example 1 provides a method for preparing sulfuryl fluoride using potassium dihydrogen phosphate as phosphate and calcium fluoride as fluorine source, and the specific method is as follows:

[0025] Take 15.6g of anhydrous calcium fluoride and 81.6g of potassium dihydrogen phosphate and add them to a ball mill for grinding for 5 hours. Add the active inorganic fluoride salts of the two obtained by grinding to 156g of acetonitrile solvent, cool the mixed solution to 5°C and maintain it at low temperature for 30 minutes, set the low temperature circulation condensation to -30°C, and then slowly add 10.8g of sulfuryl chloride under stirring. The total dropwise addition time is about 1 hour. After the dropwise addition is completed, continue to react for 4 hours. According to gas chromatography test, the purity of sulfuryl fluoride in the obtained product is 99.5%, and 7.55g of sulfuryl fluoride is prepared with a yield of 92.5%.

[0026] Example 2

[0027] Example 2 provides a method for preparing sulfuryl fluoride using potassium dihydrogen phosphate as phosphate and calcium fluoride as fluorine source, and the specific method is as follows:

[0028] Take 15.6g of anhydrous calcium fluoride and 81.6g of potassium dihydrogen phosphate and add them to a ball mill for grinding for 5 hours. Add the active inorganic fluoride salts of the two obtained by grinding to 156g of acetonitrile solvent, cool the mixed solution to 5°C and maintain it at low temperature for 30 minutes, set the low temperature circulation condensation to -30°C, and then slowly add 2.7g of sulfuryl chloride under stirring. The total dropwise addition time is about 0.5 hours. After the dropwise addition is completed, continue to react for 4 hours. According to gas chromatography test, the purity of sulfuryl fluoride in the obtained product is 99.8%, and 2g of sulfuryl fluoride is prepared with a yield of 98%.

[0029] Example 3

[0030] Example 3 provides a method for preparing sulfuryl fluoride using potassium dihydrogen phosphate as phosphate and calcium fluoride as fluorine source, and the specific method is as follows:

[0031] Take 15.6g of anhydrous calcium fluoride and 81.6g of potassium dihydrogen phosphate and add them to a ball mill for grinding for 5 hours. Add the active inorganic fluoride salts of the two obtained by grinding to 156g of acetonitrile solvent, cool the mixed solution to 5°C and maintain it at low temperature for 30 minutes, set the low temperature circulation condensation to -30°C, and then slowly add 13.5g of sulfuryl chloride under stirring. The total dropwise addition time is about 1.5 hours. After the dropwise addition is completed, continue to react for 4 hours. According to gas chromatography test, the purity of sulfuryl fluoride in the obtained product is 99.6%, and 9.16g of sulfuryl fluoride is prepared with a yield of 89.8%.

[0032] Example 4

[0033] Example 4 provides a method for preparing sulfuryl fluoride using disodium hydrogen phosphate as phosphate and calcium fluoride as fluoride source, and the specific method is as follows:

[0034] Take 15.6g of anhydrous calcium fluoride and 85.2g of sodium dihydrogen phosphate and add them to a ball mill for grinding for 9h. Add the active inorganic fluoride salts of the two obtained by grinding to 184g of tetrahydrofuran solvent, cool the mixed solution to 9°C and maintain it at low temperature for 30 minutes, set the low temperature circulation condensation to -30°C, and then slowly add 10.8g of sulfuryl chloride under stirring. The total dropwise addition time is about 1 hour. After the dropwise addition is completed, continue to react for 10 hours. According to gas chromatography test, the purity of sulfuryl fluoride in the obtained product is 99.3%, and 7.88g of sulfuryl fluoride is prepared with a yield of 96.5%.

[0035] Comparative Example 1

[0036] 15.6g of anhydrous calcium fluoride and 81.6g of potassium dihydrogen phosphate were added to a ball mill and ground for 5h. The active inorganic fluoride salts of the two obtained by grinding were added to 156g of acetonitrile solvent. The mixed solution was cooled to 5°C and maintained at low temperature for 30 minutes. Then, 10.8g of sulfuryl chloride was slowly added dropwise under stirring. The total addition time was about 1 hour. After the addition was completed, the reaction was continued for 4 hours. According to gas chromatography test, the purity of sulfuryl fluoride in the obtained product was 85.6%, and 6.88g of sulfuryl fluoride was prepared, with a yield of 84.3% and a sulfuryl fluoride chlorine content of 13.5%.

[0037] Comparative Example 2

[0038] Take 15.6g of anhydrous calcium fluoride and 85.2g of sodium dihydrogen phosphate and add them to a ball mill and grind for 9h. Add the active inorganic fluoride salts of the two obtained by grinding to 184g of tetrahydrofuran solvent, cool the mixed solution to 9°C and maintain it at low temperature for 30 minutes, then slowly add 10.8g of sulfuryl chloride under stirring, the total dropwise addition time is about 1 hour, and the reaction is continued for 10 hours after the dropwise addition is completed. According to gas chromatography test, the purity of sulfuryl fluoride in the obtained product is 80.3%, and 6.38g of sulfuryl fluoride is prepared, the yield is 78.1%, and the sulfuryl fluoride chlorine content is 18.9%.

[0039] Comparative Example 3

[0040] 15.6g of anhydrous calcium fluoride and 82.9g of potassium carbonate were added to a ball mill and ground for 5 hours. The ground product was added to 156g of acetonitrile solvent, and the mixed solution was cooled to 5°C and maintained at low temperature for 30 minutes. The low temperature circulation condensation was set to -30°C, and then 10.8g of sulfuryl chloride was slowly added dropwise under stirring. The total addition time was about 1 hour. After the addition was completed, the reaction was continued for 4 hours. No gas was generated during the reaction.

[0041] Comparative Example 4

[0042] 15.6g of anhydrous calcium fluoride and 104.5g of potassium sulfate were added to a ball mill and ground for 5 hours. The ground product was added to 156g of acetonitrile solvent, and the mixed solution was cooled to 5°C and maintained at low temperature for 30 minutes. The low temperature circulation condensation was set to -30°C, and then 10.8g of sulfuryl chloride was slowly added dropwise under stirring. The total addition time was about 1 hour. After the addition was completed, the reaction was continued for 4 hours. No gas was generated during the reaction.

[0043] The embodiments described in the content of the present invention are only for illustrating the specific operation methods and related features of the present invention, and the attached claims are intended to require all conceivable and widest possible ranges. The specific embodiments provided herein are only a few simple examples of all the combinations of embodiments. Therefore, the applicant intends that the attached claims cannot be limited by the embodiments shown in the examples of the present invention. The numerical ranges described in the claims also include their sub-ranges. In addition, any embodiment that can be obtained by simple reasoning of the present invention should also be within the scope of the claims.

Claims

1. A method for preparing sulfuryl fluoride, comprising the following steps: (1) CaF2 and M X H 3-X PO4 is ground in a ball mill to obtain an inorganic fluoride salt A having fluorination activity; (2) Inorganic fluoride salt A reacts with sulfuryl chloride in a non-aqueous polar solvent.

2. The method according to claim 1, characterized in that The step (2) further comprises: condensing sulfuryl fluoride and sulfuryl chloride in the reflux mixed gas at low temperature, and collecting sulfuryl fluoride by a gas compression pump.

3. The method according to claim 1, characterized in that M X H 3-X The cation M in PO4 is selected from one or more of lithium, cesium, sodium and potassium.

4. The method according to claim 1, characterized in that: CaF2 and M X H 3-X The molar ratio of PO4 is 1:(2.5-5), preferably 1:(4-5).

5. The method according to claim 1, characterized in that CaF2 and M X H 3-X The grinding time of PO4 is 2 to 24 hours, preferably 8 to 24 hours.

6. The method according to claim 1, characterized in that The molar ratio of the inorganic fluoride salt A, calculated as calcium fluoride, to sulfuryl chloride is 1:(0.1-0.5), preferably 1:(0.1-0.3).

7. The method according to claim 1, characterized in that The reaction time of step (2) is 1 to 24 hours, and the reaction temperature is 0°C to 68°C; preferably, the reaction time is 2 to 12 hours, and the reaction temperature is 5°C to 15°C.

8. The method according to claim 1, characterized in that The temperature of the low temperature condensation is -50°C to 0°C, preferably -40°C to -20°C.

9. The preparation method according to claim 1, characterized in that: The non-aqueous polar solvent is selected from one or more of methyl formate, ethyl formate, propyl formate, isopropyl formate, ethyl acetoacetate, n-butyl acetate, isobutyl acetate, isoamyl acetate, methyl lactate, ethyl acetate, methyl acetate, methyl tert-butyl ether, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, ethyl salicylate, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, n-hexanol, cyclohexanol, n-octanol, isooctyl alcohol, glycerol, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, tetrahydrofuran, dioxolane, propylene oxide, diethoxymethane, anisole, acetonitrile, hydroxyacetonitrile, propionitrile, butyronitrile, α-phenylbutyronitrile, isovaleronitrile, 1,3,6-hexanetrinitrile, and 1,2,4,5-benzenetetracarbonitrile.

10. The preparation method according to claim 1, characterized in that: The mass ratio of the non-aqueous polar solvent to CaF2 is (1-20):1, preferably (12-18):1.