Method for preparing an imide salt containing a fluorosulphonyl group

1. A process for preparing a compound of the following formula (IV)

R 2 —(SO 2 )—NLi—(SO 2 )—F  (IV)

wherein R 2 represents one of the following radicals: F, CF 3 , CHF 2 , CH 2 F, C 2 HF 4 , C 2 H 2 F 3 , C 2 H 3 F 2 , C 2 F 5 , C 3 F 7 , C 3 H 4 F 3 , C 3 HF 6 , C 4 F 9 , C 4 H 2 F 7 , C 4 H 4 F 5 , C 5 F 11 , C 6 F 13 , C 7 F 15 , C 8 F 17 or C 9 F 19 ;

said process comprising a step a) of reacting a sulfamide of the following formula (A):

R 0 —(SO 2 )—NH 2   (A)

wherein R 0 represents one of the following radicals: OH, Cl, F, CF 3 , CHF 2 , CH 2 F, C 2 HF 4 , C 2 H 2 F 3 , C 2 H 3 F 2 , C 2 F 5 , C 3 F 7 , C 3 H 4 F 3 , C 3 HF 6 , C 4 F 9 , C 4 H 2 F 7 , C 4 H 4 F 5 , C 5 F 11 , C 6 F 13 , C 7 F 15 , C 8 F 17 or C 9 F 19 ;

with at least one sulfur-containing acid and at least one chlorinating agent, said step a) being carried out:

at a temperature between 90° C. and 130° C., and

at a pressure of at least 8 bar abs,

wherein the reaction of step a) produces a chlorinated product of the following formula (I):

R 1 —(SO 2 )—NH—(SO 2 )—Cl  (I)

wherein R 1 represents one of the following radicals: Cl, F, CF 3 , CHF 2 , CH 2 F, C 2 HF 4 , C 2 H 2 F 3 , C 2 H 3 F 2 , C 2 F 5 , C 3 F 7 , C 3 H 4 F 3 , C 3 HF 6 , C 4 F 9 , C 4 H 2 F 7 , C 4 H 4 F 5 , C 5 F 11 , C 6 F 13 , C 7 F 15 , C 8 F 17 or C 9 F 19 .

2. The process as claimed in claim 1 , wherein the compound (A) is that wherein R 0 represents OH.

3. The process as claimed in claim 1 , wherein the sulfur-containing agent is chosen from the group consisting of chlorosulfonic acid (ClSO 3 H), sulfuric acid, oleum, and mixtures thereof.

4. The process as claimed in claim 1 , wherein the chlorinating agent is chosen from the group consisting of thionyl chloride (SOCl 2 ), oxalyl chloride (COCl 2 ), phosphorus pentachloride (PCl 5 ), phosphonyl trichloride (PCl 3 ), phosphoryl trichloride (POCl 3 ), and mixtures thereof.

5. The process as claimed in claim 1 , wherein:

the molar ratio between the sulfur-containing acid and the compound (A) is between 0.7 and 5; and/or

the molar ratio between the chlorinating agent and the compound (A) is between 2 and 10.

6. The process as claimed in claim 1 , wherein step a) is carried out at a temperature between 105° C. and 130° C.

7. The process as claimed in claim 1 , wherein step a) is carried out at a pressure greater than or equal to 8.5 bar abs.

8. The process as claimed in claim 1 , comprising a step b), subsequent to step a), said step b) comprising reacting the chlorinated compound of formula (I) obtained in the preceding step:

R 1 —(SO 2 )—NH—(SO 2 )—Cl  (I)

wherein R 1 represents one of the following radicals: Cl, F, CF 3 , CHF 2 , CH 2 F, C 2 HF 4 , C 2 H 2 F 3 , C 2 H 3 F 2 , C 2 F 5 , C 3 F 7 , C 3 H 4 F 3 , C 3 HF 6 , C 4 F 9 , C 4 H 2 F 7 , C 4 H 4 F 5 , C 5 F 11 , C 6 F 13 , C 7 F 15 , C 8 F 17 or C 9 F 19 ;

with at least one fluorinating agent, optionally in the presence of at least one organic solvent SO1.

9. The process as claimed in claim 8 , wherein the fluorinating agent is chosen from the group consisting of HF, KF, AsF 3 , BiF 3 , ZnF 2 , SnF 2 , PbF 2 , CuF 2 , and mixtures thereof.

10. The process as claimed in claim 8 , comprising a step c), subsequent to step b), of reacting the compound of formula (II) obtained in the preceding step:

R 2 —(SO 2 )—NH—(SO 2 )—F  (II)

wherein R 2 represents one of the following radicals: F, CF 3 , CHF 2 , CH 2 F, C 2 HF 4 , C 2 H 2 F 3 , C 2 H 3 F 2 , C 2 F 5 , C 3 F 7 , C 3 H 4 F 3 , C 3 HF 6 , C 4 F 9 , C 4 H 2 F 7 , C 4 H 4 F 5 , C 5 F 11 , C 6 F 13 , C 7 F 15 , C 8 F 17 or C 9 F 19 ;

with a composition comprising at least one alkali or alkaline-earth metal salt.

11. The process as claimed in claim 10 , wherein the alkali or alkaline-earth metal salt is an alkali or alkaline-earth metal carbonate, or an alkali or alkaline-earth metal hydroxide, or an alkali or alkaline-earth metal chloride, or an alkali or alkaline-earth metal fluoride.

12. The process as claimed in claim 10 , comprising a step d), subsequent to step c), of cation exchange between a compound of formula (III) obtained in the preceding step:

R 2 —(SO 2 )—NM-(SO 2 )—F  (III)

wherein R2 is as defined in claim 1 , and M represents a monovalent or divalent cation of an alkali or alkaline-earth metal;

and at least one lithium salt.

13. The process as claimed in claim 1 , wherein R 2 represents F.

14. The process as claimed in claim 1 , wherein the sulfur-containing agent is sulfuric acid or oleum.

15. The process as claimed in claim 1 , wherein the sulfur-containing agent is sulfuric acid.

16. The process as claimed in claim 1 , wherein the chlorinating agent is thionyl chloride.