Method for preparing imide salts containing a fluorosulphonyl group

Abstract

A fluorination process for obtaining fluorinated compounds including at least one fluorosulfonyl group. More particularly, a process for preparing a fluorinated compound of formula (II), including at least one step of reacting a compound of formula (I) with anhydrous hydrofluoric acid in at least one organic solvent, in which R1 is equal to R2 except in the specific case where R1═Cl, then R2═F, and when R1 is equal to R2, R1 and R2 represent an electron-withdrawing group which has a Hammett parameter σp of greater than 0, such as F, CF.sub.3, CHF.sub.2, CH.sub.2F, C.sub.2HF.sub.4, C.sub.2H.sub.2F.sub.3, C.sub.2H.sub.3F.sub.2, C.sub.2F.sub.5, C.sub.3F.sub.7, C.sub.3H.sub.2F.sub.5, C.sub.3H.sub.4F.sub.3, C.sub.3HF.sub.6, C.sub.4F.sub.9, C.sub.4H.sub.2F.sub.7, C.sub.4H.sub.4F.sub.5, C.sub.5F.sub.11, C.sub.3F.sub.5OCF.sub.3, C.sub.2F.sub.4OCF.sub.3, C.sub.2H.sub.2F.sub.2OCF.sub.3, CF.sub.2OCF.sub.3, C.sub.6F.sub.13, C.sub.7F.sub.15, C.sub.8F.sub.17 or C.sub.9F.sub.19, and M represents a hydrogen atom, an alkali metal, an alkaline-earth metal or a quaternary ammonium cation.

Claims

1. A process for preparing a fluorinated compound of formula (II), comprising at least one step of reacting a compound of formula (I) with anhydrous hydrofluoric acid in at least one organic solvent according to the following scheme: ##STR00002## in which: R.sub.1 is equal to R.sub.2 except in the specific case where R.sub.1═Cl, then R.sub.2═F, and where R.sub.1 is equal to R.sub.2, R.sub.1 and R.sub.2 is an electron-withdrawing group which has a Hammett parameter σ.sub.p greater than 0 and is selected from the group consisting of F, CF.sub.3, CHF.sub.2, CH.sub.2F, C.sub.2HF.sub.4, C.sub.2H.sub.2F.sub.3, C.sub.2H.sub.3F.sub.2, C.sub.2F.sub.5, C.sub.3F.sub.7, C.sub.3H.sub.2F.sub.5, C.sub.3H.sub.4F.sub.3, C.sub.3HF.sub.6, C.sub.4F.sub.9, C.sub.4H.sub.2F.sub.7, C.sub.4H.sub.4F.sub.5, C.sub.5F.sub.11, C.sub.3F.sub.5OCF.sub.3, C.sub.2F.sub.4OCF.sub.3, C.sub.2H.sub.2F.sub.2OCF.sub.3, CF.sub.2OCF.sub.3, C.sub.6F.sub.13, C.sub.7F.sub.15, C.sub.8F.sub.17 and C.sub.9F.sub.19, and M is selected from the group consisting of a hydrogen atom, an alkali metal, an alkaline-earth metal and a quaternary ammonium cation.

2. The process as claimed in claim 1, wherein the at least one organic solvent has a donor number of between 1 and 70.

3. The process as claimed in claim 1, wherein the at least one organic solvent is selected from the group consisting of esters, nitriles or dinitriles, ethers or diethers, amines and phosphines.

4. The process as claimed in claim 1, wherein the reaction step is carried out at a temperature T of between 0° C. and the boiling point of the at least one organic solvent.

5. The process as claimed in claim 1, wherein the reaction step is carried out at a pressure P of between 0 and 16 bar absolute.

6. The process as claimed in claim 1, wherein the compound of formula (I) is dissolved in the at least one organic solvent prior to the step of reacting with anhydrous HF.

7. The process as claimed in claim 1, wherein the weight ratio between the compound of formula (I) and the at least one organic solvent is between 0.001 and 10.

8. The process as claimed in claim 1, wherein the molar ratio between the compound of formula (I) and the HF used is between 0.01 and 0.5.

9. The process as claimed in claim 1, comprising a cation exchange step after the fluorination step in order to obtain alkali metal salts, alkaline-earth metal salts or quaternary ammonium cation salts.

10. The process as claimed in claim 1, wherein the compound of formula (II) is selected from the group consisting of LiN(FSO.sub.2).sub.2, LiNSO.sub.2CF.sub.3SO.sub.2F, LiNSO.sub.2C.sub.2F.sub.5SO.sub.2F, LiNSO.sub.2CF.sub.2OCF.sub.3SO.sub.2F, LiNSO.sub.2C.sub.3HF.sub.6SO.sub.2F, LiNSO.sub.2C.sub.4F.sub.9SO.sub.2F, LiNSO.sub.2C.sub.5F.sub.11SO.sub.2F, LiNSO.sub.2C.sub.6F.sub.13SO.sub.2F, LiNSO.sub.2C.sub.7F.sub.15SO.sub.2F, LiNSO.sub.2C.sub.8F.sub.17SO.sub.2F and LiNSO.sub.2C.sub.9F.sub.19SO.sub.2F.

11. The process as claimed in claim 1, wherein the at least one organic solvent has a donor number of between 5 and 65.

12. The process as claimed in claim 1, wherein the reaction step is carried out at a temperature T of between 5° C. and the boiling point of the at least one organic solvent.

13. The process as claimed in claim 1, wherein the weight ratio between the compound of formula (I) and the at least one organic solvent is between 0.005 and 5.

14. The process as claimed in claim 1, wherein the molar ratio between the compound of formula (I) and the HF used is between 0.05 and 0.5.

15. The process as claimed in claim 1, wherein the process has a fluorination yield of between 85% and 100%.

16. The process as claimed in claim 1, wherein the at least one organic solvent is selected from the group consisting of methyl acetate, ethyl acetate, butyl acetate, acetonitrile, propionitrile, isobutyronitrile, glutaronitrile, dioxane, tetrahydrofuran, triethylamine, tripropylamine, diethylisopropylamine, pyridine, trimethylphosphine, triethylphosphine and diethylisopropylphosphine.

17. The process as claimed in claim 1, wherein the HF is in gaseous form.

18. The process as claimed in claim 1, wherein the compound of formula (II) is LiN(FSO.sub.2).sub.2.

Description

EXAMPLE 1

(1) In an 800 ml autoclave, 28 g of (ClSO.sub.2).sub.2NH are dissolved in 50 ml of acetonitrile. 10 g of HF are then added. The pressure is then 0.34 bar absolute and the temperature is maintained at 10° C. The reaction is left to stir in a closed medium for 18 h. The excess HF is removed by pumping. The reaction medium is then treated with lithium carbonate. The solution is filtered and then evaporated and the residue is analyzed by .sup.19F NMR. The analysis shows the presence of 85% of totally fluorinated product (FSO.sub.2).sub.2NLi, 7.5% of FSO.sub.3Li and 7.5% of FSO.sub.2NH.sub.2. The latter two are the compounds formed during the degradation of the starting product.

EXAMPLE 2

(2) In an 800 ml autoclave, 31.7 g of (ClSO.sub.2).sub.2NH are dissolved in 50 ml of acetonitrile. 10 g of HF are then added. The pressure is then 0.75 bar absolute and the temperature is maintained at 20° C. The reaction is left to stir in a closed medium for 18 h. The excess HF is removed by pumping. The reaction medium is then treated with lithium carbonate. The solution is filtered and then evaporated and the residue is analyzed by .sup.19F NMR. The analysis shows the presence of 100% of totally fluorinated product (FSO.sub.2).sub.2NLi and the absence of the degradation products FSO.sub.3Li and FSO.sub.2NH.sub.2.

EXAMPLE 3

(3) In an 800 ml autoclave, 61 g of (ClSO.sub.2).sub.2NH are dissolved in 50 ml of 1,4-dioxane. 20 g of HF are then added. The pressure is then 2.3 bar absolute and the temperature is maintained at 25° C. The reaction is left to stir in a closed medium for 18 h. The excess HF is removed by pumping. The reaction medium is then treated with lithium carbonate. The solution is filtered and then evaporated and the residue is analyzed by .sup.19F NMR. The analysis shows the presence of 100% of totally fluorinated product (FSO.sub.2).sub.2NLi and the absence of the degradation products FSO.sub.3Li and FSO.sub.2NH.sub.2.