PROCESS FOR PREPARING AN IMID SALT CONTAINING A GROUP

FLUOROSULFONYL

FIELD OF THE INVENTION

The present invention relates to a process for preparing imide salts containing a fluorosulfonyl group.

TECHNICAL BACKGROUND

Sulfonylimide type anions, due to their very low basicity, are increasingly used in the field of energy storage in the form of inorganic salts in batteries, or organic salts in supercapacitors or in the field of liquids. ionic. With the battery market booming and the reduction of battery manufacturing costs becoming a major issue, a large-scale, low-cost synthesis process of this type of anions is necessary.

In the specific field of Li-ion batteries, the salt currently most used is LiPF 6 but this salt shows many disadvantages such as limited thermal stability, sensitivity to hydrolysis and therefore lower battery safety. . Recently, new salts possessing the FS0 2 group have been studied and have demonstrated many advantages such as better ionic conductivity and resistance to hydrolysis. One of these salts, LiFSI (LiN (FS0 2 ) 2 ) has shown very interesting properties which make it a good candidate to replace LiPF 6 .

Most of the processes for preparing imide salts containing a fluorosulfonyl group include many steps, which results in the formation of side products having physical properties such that their removal can be complex, and / or require steps of expensive purification. Moreover, the accumulation of steps can cause a reduction in the final yields of LiFSI. In addition, certain processes are not applicable on an industrial scale, and / or generate effluents which may be difficult to treat. Depending on the complexity required for the purification steps, the quantity of effluent generated can be very large and thus lead to significant treatment costs.

There is therefore a need for a process for preparing imide salts containing a fluorosulfonyl group which does not have at least one of the aforementioned drawbacks.

DESCRIPTION OF THE INVENTION

The present invention relates to a process for preparing a compound of the following formula:

R 2 - (S0 2 ) -NM- (S0 2 ) -F (III)

in which :

- 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 Fg, C 4 H 2 F 7 , C 4 H F 5, C5F1 1, CeF I 3 , C 7 F 15, C S FI 7 OR C9F19, preferably R 2 representing F;

- M represents a monovalent or divalent cation, preferably M represents a monovalent cation;

said method comprising:

- a step b) of fluorination of a compound of formula (I) below:

R I - (S0 2 ) -NH- (S0 2 ) -CI (I)

in which Ri represents one of the following radicals: Cl, F, CF 3 , CHF 2 , CH 2 F, C 2 HF, C 2 H 2 F 3 , C 2 H 3 F 2 , C 2 F 5 , C 3 F 7J C 3 H F 3 , C 3 HF 6 , C 4 Fg, C 4 H 2 F 7 , C 4 H F 5 , C5F1 1,

C 6 F I 3 , C 7 F 15 , C 8 F I 7 OR C9F19 , Ri preferably representing Cl; with at least one fluorinating agent, preferably in the presence of at least one SOI organic solvent;

- a step c) of distilling the composition obtained in step b), said composition comprising a compound of following formula (II):

R 2 - (SO 2 ) -NH- (SO 2 ) -F (II).

The method according to the invention can comprise an optional step d) of dissolving the composition obtained in step c) in an organic solvent SO 2.

According to one embodiment, the method according to the invention comprises a step e) of bringing the composition obtained in step c) or step d) into contact with a composition comprising at least one alkali or alkaline earth metal salt. , making it possible to lead to a compound of the following formula (III):

R 2 - (S0 2 ) -NM- (S0 2 ) -F (III)

R 2 and M being as defined above.

The process according to the invention can comprise a cation exchange step f) to convert a compound of formula (III) into another compound of formula (III), but for which M is different.

Preferably, the present invention relates to a process for preparing a compound of formula (III) as defined above, said process comprising:

- a step a) comprising the reaction of a sulfonamide of the following formula (A):

Ro- (S0 2 ) -NH 2 (A)

in which 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 Fg, C 4 H 2 F 7 , C 4 H F 5 , C 5 F 11 , CeF I3 ,

C 7 F 15, C 8 F 1 7 OR CgFig preferably R 0 representing OH;

with at least one sulfur-containing acid and at least one chlorinating agent, to form a compound of formula (I):

R I - (S0 2 ) -NH- (S0 2 ) -CI (I)

in which Ri 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 2J C 2 F 5 , C 3 F 7J C 3 H 4 F 3J C 3 HF 6 , C 4 Fg, C 4 H 2 F 7 , C 4 H 4 F 5, C 5 F 11 , CeF I3 , C 7 F 15 , C 8 FI 7 OR C 9 F 19, Ri preferably representing Cl;

a step b) of fluorinating a compound of formula (I) as defined above with at least one fluorinating agent, preferably in the presence of at least one SOI organic solvent;

- a step c) of distilling the composition obtained in step b), said composition comprising a compound of following formula (II):

R 2 - (SO 2 ) -NH- (SO 2 ) -F (II).

The method according to the invention advantageously makes it possible to remedy at least one of the drawbacks of the existing methods. It advantageously allows:

the preparation of a compound of formula (III), such as for example LiFSI, on an industrial scale, and at lower cost; and or

the preparation of a compound of formula (III), such as for example LiFSI, having a high purity, which allows in particular its use in the electrolytes of Li-ion batteries; and or

o reduction of effluents to be treated.

Chlorination step a)

According to one embodiment, the aforementioned process further comprises a step a), prior to step b), comprising the reaction of a sulfonamide of the following formula (A):

R 0 - (SO 2 ) -NH 2 (A)

in which 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 2J C 2 F 5 , C 3 F 7 , C 3 H 4 F 3 , C 3 HF 6 , C 4 Fg, C 4 H 2 F 7 , C 4 H 4 F 5 , C 5 F 11 , CeF I 3 , C 7 F 15 , C 8 F 17

OR C9F19;

with at least one sulfur-containing acid and at least one chlorinating agent, to form a compound of formula (I) as defined above.

Preferably, the compound (A) is that in which R 0 represents OH.

Step a) can be carried out:

o at a temperature between 30 ° C and 150 ° C; é ^ or

o with a reaction time of between 1 hour and 7 days; and or

o at a pressure between 1 bar abs and 20 bar abs.

According to the invention, the sulfur-containing agent can be chosen from the group consisting of chlorosulfonic acid (CIS0 3 H), sulfuric acid, oleum, and their mixtures.

According to the invention, the chlorinating agent can be chosen from the group consisting of thionyl chloride (SOCI 2 ), oxalyl chloride (COCI) 2 , phosphorus pentachloride (PCI 5 ), phosphonyl trichloride (PCI 3 ), phosphoryl trichloride (POCI 3 ), and mixtures thereof. Preferably, the chlorinating agent is thionyl chloride.

The chlorination step a) can be carried out in the presence of a catalyst, such as, for example, chosen from a tertiary amine (such as methylamine, triethylamine, or diethylmethylamine); pyridine; and 2,6-lutidine.

The molar ratio between the sulfur acid and the compound (A) (in particular in which R 0 = OH) can be between 0.7 and 5, preferably between 0.9 and 5.

The molar ratio between the chlorinating agent and the compound (A) (in particular in which Ro = OH), can be between 2 and 10, preferably between 2 and 5.

In particular, when the sulfur-containing agent is chlorosulfonic acid, the molar ratio between the latter and the compound (A) (in particular in which R 0 = OH) is between 0.9 and 5, and / or the molar ratio between the chlorinating agent and the compound (A), in particular with R 0 = OH, is between 2 and 5.

In particular, when the sulfur-containing agent is sulfuric acid (or oleum), the molar ratio between sulfuric acid (or oleum) and compound (A) (in particular in which R 0 = OH) , is between 0.7 and 5.

In particular, when the sulfur-containing agent is sulfuric acid (or oleum), the molar ratio between sulfuric acid (or oleum) and compound (A) (in particular in which R 0 = OH) is between 0.9 and 5, and / or the molar ratio between the chlorinating agent and the compound (A), (in particular in which R 0 = OH) is between 2 and 10.

Step a) advantageously makes it possible to form a compound of formula (I):

R I - (S0 2 ) -NH- (S0 2 ) -CI (I)

in which Ri is as defined above, and in particular in which Ri represents Cl.

Fluoridation step b)

The process according to the invention comprises a step b) of fluorinating a compound of formula (I) below:

Rr (S0 2 ) -NH- (S0 2 ) -CI (I)

in which Ri 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 2J C 2 F 5 , C 3 F 7 , C 3 H 4 F 3 , C 3 HF 6 , C 4 Fg, C 4 H 2 F 7 , C 4 H 4 F 5 , C 5 F 11 , CeF - | 3 , C 7 F 15 , C 8 F 17or C 9 F 19, Ri preferably representing Cl;

with at least one fluorinating agent, preferably in the presence of at least one SOI organic solvent.

Step b) allows in particular the fluorination of the compound of formula (I) into a compound of formula (II):

R 2 - (S0 2 ) -NH- (S0 2 ) -F (II)

in which 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 7J C 3 H 4 F 3J C 3 HF 6 , C 4 Fg, C 4 H 2 F 7 , C 4 H 4 F 5 , C 5 F 11 , CeF I 3 , C 7 F 15 , C 8 F 17 OR C 9 F 19 , preferably R2 representing F.

Preferably, in formula (II) above, R 2 represents F, CF 3 , CHF 2 , or CH 2 F. It is particularly preferred that R 2 represents F.

According to one embodiment, the fluorinating agent is chosen from the group consisting of HF (preferably anhydrous HF), KF, AsF 3 , BiF 3 , ZnF 2 , SnF 2 , PbF 2 , CuF 2 , and their mixtures , the fluorinating agent preferably being HF, and even more preferably anhydrous HF.

In the context of the invention, by “anhydrous HF” is meant THF containing less than 500 ppm of water, preferably less than 300 ppm of water, preferably less than 200 ppm of water.

Step b) of the process is preferably carried out in at least one SOI organic solvent. The SOI organic solvent preferably has a donor number between 1 and 70 and advantageously between 5 and 65. The donor index of a solvent represents the value -DH, DH being the enthalpy of the interaction between the solvent and antimony pentachloride (according to the method described in Journal of Solution Chemistry, vol. 13, no. 9, 1984). As SOI organic solvent, mention may in particular be made of esters, nitriles, dinitriles, ethers, diethers, amines, phosphines, and mixtures thereof.

Preferably, the SOI organic solvent is chosen from the group consisting of methyl acetate, ethyl acetate, butyl acetate, acetonitrile, propionitrile, isobutyronitrile, glutaronitrile , dioxane, tetrahydrofuran, triethylamine, tripropylamine, diethylisopropylamine, pyridine, trimethylphosphine, triethylphosphine, diethylisopropylphosphine, and mixtures thereof. In particular, the SOI organic solvent is dioxane.

Step b) can be carried out at a temperature between 0 ° C. and the boiling point of the SOI organic solvent (or of the mixture of SOI organic solvents). Preferably, step b) is carried out at a temperature between 5 ° C and the boiling point of the SOI organic solvent (or of the mixture of SOI organic solvents), preferably between 20 ° C and the boiling point of the SOI. SOI organic solvent (or mixture of SOI organic solvents).

Step b), preferably with anhydrous hydrofluoric acid, can be carried out at a pressure P, preferably between 0 and 16 bar abs.

This step b) is preferably carried out by dissolving the compound of formula (I) in the organic SOI solvent, or the mixture of SOI organic solvents, prior to the step of reaction with the fluorinating agent, preferably with Anhydrous THF.

The mass ratio between the compound of formula (I) and the SOI organic solvent, or the mixture of SOI organic solvents, is preferably between 0.001 and 10, and advantageously between 0.005 and 5.

According to one embodiment, anhydrous THF is introduced into the reaction medium, preferably in gaseous form.

The molar ratio x between the fluorinating agent, preferably the anhydrous HF, and the compound of formula (I) used is preferably between 1 and 10, and advantageously between 1 and 5.

The reaction step with the fluorinating agent, preferably anhydrous GI-IF, can be carried out in a closed environment or in an open environment, preferably step b) is carried out in an open environment with in particular release of HCl in the form gas.

The fluorination reaction typically leads to the formation of HCl, the majority of which can be degassed from the reaction medium (just like the excess HF if the fluorinating agent is HF), for example by stripping with a neutral gas (such as nitrogen, helium or argon).

However, residual THF and / or HCl can be dissolved in the reaction medium. In the case of HCl, the quantities are very low because at the working pressures and temperature, the HCl is mainly in gas form.

The composition obtained at the end of step b) can be stored in an HF resistant container.

The composition obtained in step b) can comprise HF (it is in particular unreacted HF), the compound of formula (II) above, the SOI solvent (such as, for example, dioxane), and optionally HCl, and / or optionally heavy compounds.

distillation

The process according to the invention comprises a step c) of distilling the composition obtained in step b), said composition comprising a compound of the following formula (II):

R 2 - (SO 2 ) -NH- (SO 2 ) -F (II).

According to one embodiment, step c) of distilling the composition obtained in step b) makes it possible to form and recover:

o a first stream F1 comprising HF, optionally the organic solvent SOI and / or optionally HCl, preferably at the top of the distillation column, said stream F1 being gaseous or liquid;

o a second stream F2 comprising the compound of formula (II), and optionally heavy compounds, preferably at the bottom of the distillation column, said stream F2 preferably being liquid.

When the stream F2 comprises heavy compounds, it can be subjected to an additional distillation step in a second distillation column, to form and recover:

o an F2-1 stream comprising the compound of formula (II) free from heavy compounds, preferably at the top of the distillation column, said F2-1 stream preferably being liquid, o an F2-2 stream comprising the heavy compounds and the compound of formula (II), preferably at the bottom of the distillation column, said stream F2-2 containing less than 10% by weight of the compound of formula (II) contained in the composition obtained in step b), preferably less of 7% by weight, and preferably less than 5% by weight, said stream F2-2 preferably being liquid.

According to one embodiment, step c) of distillation of the composition obtained in step b) makes it possible to form and recover, thanks to the use of two distillation columns: a first stream F1 comprising HF, optionally the SOI organic solvent and / or optionally HCl at the top of the first distillation column, said stream F1 being gaseous or liquid;

o a second stream F2 comprising the compound of formula (II), and optionally heavy compounds at the bottom of the first distillation column, said stream F2 preferably being liquid;

said stream F2 being subjected to a distillation step in a second distillation column, to form and recover:

o a stream F2-1 comprising the compound of formula (II) free from heavy compounds at the top of the second distillation column, said stream F2-1 preferably being liquid,

o a stream F2-2 comprising the heavy compounds and the compound of formula (II), at the bottom of the second distillation column, said stream F2-2 containing less than 10% by weight of the compound of formula (II) contained in the composition obtained in step b), preferably less than 7% by weight, and preferably less than 5% by weight, said stream F2-2 preferably being liquid.

In the context of the invention, the term “heavy compounds” is understood to mean organic compounds having a boiling point higher than that of the compound of formula (II). They can result from reactions of cleavage of the compound of formula (I) leading for example to compounds such as FS0 2 NH 2 , and / or from solvent degradation reactions leading to the formation of oligomers.

According to one embodiment, step c) of distilling the composition obtained in step b) makes it possible to form and recover:

o a first stream F'1 comprising HF, optionally the organic solvent SOI and / or optionally HCl, preferably at the top of the distillation column, said stream F'1 being gaseous or liquid;

o a second stream F'2 comprising the compound of formula (II), preferably recovered by lateral withdrawal, said stream F'2 preferably being liquid; o a third stream F'3 comprising heavy substances and the compound of formula (II), preferably at the bottom of the distillation column, said stream F'3 containing less than 10% by weight of the compound of formula (II) contained in the composition obtained in step b), preferably less than 7% by weight, and preferentially less than 5% by weight, said stream F′3 preferably being liquid.

In order to carry out the side draw-off, the distillation column can contain at least one tray.

The distillation step c) can be carried out at a pressure ranging from 0 to 5 bar abs, preferably from 0 to 3 bar abs, preferably from 0 to 2 bar abs, and advantageously from 0 to 1 bar abs.

Stage c) of distillation can be carried out:

o at a temperature at the bottom of the distillation column ranging from 150 ° C to 200 ° C, preferably from 160 ° C to 180 ° C, and preferably from 165 ° C to 175 ° C, at a pressure of 1 bar abs; or

o at a temperature at the bottom of the distillation column ranging from 30 ° C to 100 ° C, preferably from 40 ° C to 90 ° C, and preferably at 40 ° C to 85 ° C, at a pressure of 0.03 bar abs.

Step c) of distillation can be carried out in any conventional device. It may be a distillation device comprising a distillation column, a boiler and a condenser.

The distillation column can include:

o at least one packing such as for example a loose packing and / or a structured packing,

and or

o trays such as, for example, perforated trays, fixed valve trays, movable valve trays, domed trays, or combinations thereof.

The height of the distillation column typically depends on the nature of the compounds to be separated. Typically, depending on the flow rates used, the distillation column can have any type of diameter: small (less than or equal to 1 meter) or large (greater than 1 meter).

The material of the distillation column, of its internal constituents (packing and / or trays), of the boiler, and / or of the condenser is advantageously chosen from materials resistant to corrosion, due to the potential presence of HF and / or HCl in the composition subjected to distillation.

The corrosion resistant materials can be chosen from enamelled steels, nickel, titanium, chromium, graphite, silicon carbides, nickel base alloys, cobalt base alloys, carbon base alloys. chromium, steels partially or totally coated with a protective coating of fluoropolymer (such as for example PVDF: polyvinylidene fluoride, PTFE: polytetrafluoroethylene, PFA: copolymer of C 2 F 4 and perfluorinated vinyl ether, FEP: copolymer of C 2 F 4 and C 3 F 6, ETFE: copolymer of ethylene and tetrafluoroethylene, or FKM: copolymer of hexafluoropropylene and difluoroethylene).

The nickel-based alloys are preferably alloys comprising at least 40% by weight of nickel, preferably at least 50% by weight of nickel relative to the total weight of the alloy. Mention may for example be made of the Inconel®, Hastelloy® or Monel® alloys.

The streams F1 and F'1 can comprise HF, HCl, the organic solvent SOI (in particular dioxane).

According to one embodiment, the stream F1 comprises from 2 to 70% by weight of HF, preferably from 5 to 60% by weight of HF relative to the total weight of the stream F1, and from 30% to 98% by weight of SOI organic solvent, preferably from 40% to 95% by weight of SOI, relative to the total weight of the stream F1.

According to one embodiment, the stream F'1 comprises from 2 to 70% by weight of HF, preferably from 5 to 60% by weight of HF relative to the total weight of the stream F'1, and from 30% to 98 % by weight of organic solvent SOI, preferably from 40% to 95% by weight of SOI, relative to the total weight of the stream F'1.

According to one embodiment, the stream F2 comprises from 50 to 100% by weight of compound of formula (II), preferably from 70 to 99% by weight of compound of formula (II) relative to the total weight of the stream F2.

According to one embodiment, the stream F'2 comprises from 50 to 100% by weight of compound of formula (II), preferably from 70 to 99% by weight of compound of formula (II) relative to the total weight of the stream F'2.

According to one embodiment, the stream F2-1 comprises from 50 to 100% by weight of compound of formula (II), preferably from 70 to 99% by weight of compound of formula (II) relative to the total weight of the stream F2-1.

Step c) advantageously allows the recovery of a compound of formula (II) having a high purity. The use of a compound of formula (II) of high purity advantageously makes it possible to prepare a compound of formula (III), in particular LiFSI, having high purity, without requiring additional purification steps.

According to one embodiment, the method according to the invention comprises a step d) of dissolving the composition obtained in step c) in an organic solvent SO2, said solvent SO2 preferably being aprotic polar.

The organic solvent SO2 can be a water miscible solvent.

In the context of the invention, the term “solvent miscible with water” is understood to mean a solvent which does not form a macroscopic phase separation.

The organic solvent SO2 can be selected from the group consisting of ethers, diethers, nitriles, amines, carbonates or phosphines. Preferably, the organic solvent SO2 is chosen from the group consisting of methyl acetate, ethyl acetate, butyl acetate, acetonitrile, propionitrile, isobutyronitrile, glutaronitrile. , dioxane, tetrahydrofuran, triethylamine, tripropylamine, diethylisopropylamine, pyridine, diethylcarbonate, dimethylcarbonate, methylethylcarbonate, ethylene carbonate, trimethylphosphine, triethylphosphine, diethylisopropylphosphine and their mixtures , the solvent SO2 preferably being dioxane or butyl acetate or acetonitrile, and advantageously dioxane.

Preferably, step d) comprises adding said solvent SO 2 to the composition obtained in step b) or in step c).

In the embodiment where the method comprises step c), step d) comprises in particular the dissolving of the stream F2 (or of the stream F2-1 or of the stream F'2) in an organic solvent S02.

Step e)

According to one embodiment, the method according to the invention comprises a step e) of bringing the composition obtained in step c) or step d) into contact with a composition

comprising at least one alkali metal or alkaline earth metal salt, making it possible to produce a compound of the following formula (III):

R 2 - (S0 2 ) -NM- (S0 2 ) -F (III)

R 2 and M being as defined above.

Step e) advantageously makes it possible to convert the compound of formula (II) into a compound of above-mentioned formula (III):

R 2 - (S0 2 ) -NM- (S0 2 ) -F (III)

in which :

- 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 Fg, C 4 H 2 F 7 , C 4 H 4 F5 , C5F1 1, C 3 F I 3 , C 7 F 15, C 8 F 1 7 or C9F19, R 2 preferably representing F; and

- M represents a monovalent cation, preferably K + or Li + or Na + , or a divalent cation, M preferably representing a monovalent cation.

Typically, step e) can be carried out from the composition obtained in step c) (stream F2, or stream F2-1 or stream F'2), or from the composition obtained in step d ) or after any intermediate step between step c) and step e).

According to one embodiment, the composition comprising at least one alkali or alkaline earth metal salt is an aqueous composition, preferably an aqueous suspension or an aqueous solution.

According to another embodiment, the composition comprising at least one alkali or alkaline earth metal salt is a solid composition, preferably the composition consists of at least one alkali or alkaline earth metal salt.

The contacting step may correspond to the addition of the composition obtained in step c) or step d) to the composition comprising at least one alkali or alkaline earth metal salt, or the reverse. Preferably, the composition obtained in step c) or d) is added to the composition comprising at least one alkali or alkaline earth metal salt.

Step e) can be carried out in a reactor, preferably comprising at least one stirring system.

The alkali or alkaline earth metal salt can be a salt of the M cation.

According to one embodiment, the alkali or alkaline earth metal salt is chosen from the group consisting of MOH, M0H, H 2 0, MHC0 3 , M 2 C0 3 , MCI, M (OH) 2 , M (0H) 2 , H 2 0, M (HC0 3 ) 2 , MC0 3 , MCI 2 , and mixtures thereof, M being as defined above. Of

preferably, the alkali or alkaline earth metal salt is selected from the group consisting of MOH, M0H, H 2 0, MHC0 3 , M 2 C0 3 , MCI, and mixtures thereof.

Preferably, the alkali or alkaline earth metal salt is selected from the group consisting of LiOH, Li0H, H 2 0, LiHC0 3 , U 2 C0 3 , LiCl, KOH, K0H, H 2 0, KHC0 3 , K 2 C0 3 , KOI, NaOH, NaOH, H 2 0, NaHC0 3 , Na 2 C0 3 , NaCl, and mixtures thereof, the salt preferably being a potassium salt, and advantageously K 2 C0 3 .

The composition, when it is an aqueous composition comprising at least one alkali or alkaline earth metal salt, can be prepared by any conventional means for preparing an aqueous alkaline composition. It may for example be the dissolution of the alkali or alkaline earth metal salt in ultrapure or deionized water, with stirring.

Preferably, the above-mentioned process comprises a step e) comprising the addition of the composition obtained in step c) or step d), said composition comprising a compound of above-mentioned formula (II):

R 2 - (S0 2 ) -NH- (S0 2 ) -F (II),

R 2 being as defined above, and preferably R 2 representing F,

in an aqueous composition comprising at least one potassium salt or one lithium salt, preferably a potassium salt.

To determine the amount of alkali metal or alkaline earth metal salt to be introduced, it is typically possible to carry out an analysis of the total acidity of the mixture to be neutralized.

According to one embodiment, step e) is such that:

- the molar ratio of the alkali metal or alkaline earth metal salt divided by the number of basicities of said salt relative to the compound of formula (II) is greater than or equal to 1, preferably less than 5, preferably less than 3, preferably between 1 and 2; and or

the mass ratio of the alkali metal or alkaline earth metal salt to the mass of water in the aqueous composition is between 0.1 and 2, preferably between 0.2 and 1, preferably between 0.3 and 0.7.

For example, the Li 2 C0 3 and K 2 C0 3 salts each have a number of basicities equal to 2.

Step e) of the process according to the invention can be carried out at a temperature less than or equal to 40 ° C, preferably less than or equal to 30 ° C, preferably less than or equal to 20 ° C, and in particular less than or equal to 15 ° C.

According to one embodiment, the method according to the invention comprises an additional step of filtering the composition obtained in step e), resulting in a filtrate F and a cake G.

The compound of formula (III) prepared can be contained in the filtrate F and / or in the cake G.

The filtrate F can be subjected to at least one extraction step with an organic solvent S03 typically slightly soluble in water, in order to extract the compound of formula (III) mentioned above in an organic phase. The extraction step typically leads to the separation of an aqueous phase and an organic phase.

In the context of the invention, and unless otherwise indicated, by “slightly soluble in water” is meant a solvent whose solubility in water is less than 5% by weight.

The aforementioned organic solvent SO 3 is in particular chosen from the following families: esters, nitriles, ethers, chlorinated solvents, aromatic solvents, and mixtures thereof. Preferably, the organic solvent SO 3 is chosen from dichloromethane, ethyl acetate, butyl acetate, tetrahydrofuran, diethyl ether, and mixtures thereof. In particular, the organic solvent SO3 is butyl acetate.

For each extraction, the mass quantity of organic solvent used can vary between 1/6 and 1 times the mass of the filtrate F. The number of extractions can be between 2 and 10.

Preferably, the organic phase, resulting from the extraction (s), has a content by weight of compound of formula (III) ranging from 5% to 40% by weight.

The separated organic phase (obtained at the end of the extraction) can then be concentrated to reach a concentration of compound of formula (III) of between 30% and 60%, preferably between 40% and 50% by mass, said concentration which can be achieved by any means of evaporation known to those skilled in the art.

The above-mentioned cake G can be washed with an organic solvent S04 chosen from the following families: esters, nitriles, ethers, chlorinated solvents, aromatic solvents, and mixtures thereof. Preferably, the organic solvent SO4 is chosen from dichloromethane, ethyl acetate, butyl acetate, tetrahydrofuran, acetonitrile, diethyl ether, and mixtures thereof. In particular, the organic solvent SO4 is butyl acetate.

The quantity by mass of organic solvent SO4 used can vary between 1 and 10 times the weight of the cake. The total amount of organic solvent S04 intended for washing can be

used all at once or in several times with the aim in particular of optimizing the dissolution of the compound of formula (III).

Preferably, the organic phase, resulting from the washing (s) of the cake G, has a content by mass of compound of formula (III) ranging from 5% to 20% by mass.

The separated organic phase resulting from the washing (s) of the cake G can then be concentrated to reach a concentration of compound of formula (III) of between 30% and 60%, preferably between 40% and 50% by mass , said concentration possibly being achieved by any means of evaporation known to those skilled in the art.

According to one embodiment, the organic phases resulting from the extraction (s) of the filtrate F and from the washing (s) of the cake G can be combined together, before the concentration step.

Step f) cation exchange

The method according to the invention can comprise after step e), a cation exchange step f) to convert a compound of formula (III) into another compound of formula (III), but for which M represents a cation monovalent different.

Preferably, this step comprises the reaction between a compound of formula (III) obtained in step e) above:

R 2 - (S0 2 ) -NM- (S0 2 ) -F (III)

in which :

- 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 Fg, C 4 H 2 F 7 , C 4 H 4 F5 , C5F1 1, C 3 F 1 3 , C 7 F 15, C 8 F 1 7 OR

C9F19, preferably R 2 representing F;

- M represents a monovalent or divalent cation, preferably monovalent,

with an alkali or alkaline earth metal salt whose cation is other than M (for example M ').

For example, if the compound of formula (III) obtained in step e) is a compound for which M represents K + , then the process can comprise a step f) of cation exchange of this compound with a metal salt alkaline or alkaline earth, the cation of which is not K + , for example with a lithium salt.

For example, if step e) results in a compound of formula (III-A):

R 2 - (S0 2 ) -NM- (S0 2 ) -F (lll-A)

in which :

- 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 Fg, C 4 H 2 F 7 , C 4 H 4 F5 , C5F1 1, C 8 F 1 3 , C 7 F 15, C 8 F 1 7 OR

C9F19, preferably R 2 representing F;

- M represents a monovalent or divalent cation, preferably monovalent;

the process may comprise a step f) of cation exchange of the compound of formula (III-A) into a compound of formula (III-B):

R 2 - (S0 2 ) -NM '- (S0 2 ) -F (lll-B)

in which :

- 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 7J C 3 H 4 F 3J C 3 HF 6 , C 4 Fg, C 4 H 2 F 7 , C 4 H 4 F5 , C5F1 1, C 8 F 1 3 , C 7 F 15, C 8 F 1 7 OR

C9F19, preferably R 2 representing F;

- M 'represents a monovalent cation different from M.

Step g) of purification

The process according to the invention can also comprise a step of purification of the compound of formula (III) mentioned above.

This step can be carried out at the end of step e) or at the end of step f).

Step g) of purification of the compound of formula (III) can be carried out by any known conventional method. It may be, for example, an extraction method, a washing method with solvents, a reprecipitation method, a recrystallization method, or a combination thereof.

At the end of step e) above or of step f) above, the compound of formula (III) can be in the form of a composition comprising from 30% to 95% by weight of compound of formula (III) relative to the total weight of said composition.

According to a first embodiment, step g) is a step of crystallization of the compound of formula (III) mentioned above.

Preferably, during step g), the compound of above-mentioned formula (III) is cold crystallized, in particular at a temperature less than or equal to 25 ° C.

Preferably, during step g), the crystallization of the compound of formula (III) is carried out in an organic solvent S05 (“crystallization solvent”) chosen from chlorinated solvents, such as for example dichloromethane, and solvents. aromatic, such as for example toluene, in particular at a temperature less than or equal to 25 ° C. Preferably, the compound of formula (III) crystallized at the end of step d) is recovered by filtration.

The crystallization step is preferably carried out on a composition comprising between 75% and 90% by weight of the compound of formula (III). To do this, the composition obtained at the end of step e) or f) can be concentrated to obtain a solution corresponding to the above-mentioned composition. Concentration can be done by any conventional means of concentration. It can in particular be carried out under reduced pressure of between 40 mbar and 0.01 mbar at a temperature below 70 ° C, preferably below 50 ° C, preferably below 40 ° C. It can be carried out, preferably carried out according to the conditions of step v) described below.

According to a second embodiment, step g) comprises the following steps: i) optionally dissolving the compound of formula (III) in an organic solvent S'1;

ii) adding deionized water to dissolve and extract the compound of formula (III) above, forming an aqueous solution of said compound of formula (III); iii) optional concentration of said aqueous solution of said compound of formula

(ni);

iv) extraction of the compound of formula (III) from said aqueous solution, with an organic solvent S'2, preferably said solvent S2 forming an azeotropic mixture with water, this step being repeated at least once; v) concentration of the compound of formula (III) by evaporation of said organic solvent S'2 and of water, in a short path thin film evaporator, under the following conditions:

- temperature between 30 ° C and 95 ° C, preferably between 30 ° C and 90 ° C, preferably between 40 ° C and 85 ° C;

- pressure between 10 3 mbar abs and 5 mbar abs;

residence time less than or equal to 15 min, preferably less than or equal to 10 min, and advantageously less than or equal to 5 min;

vi) optionally crystallization of the compound of formula (III).

Step g) may not include step i) above, if the compound of formula (III) obtained in step e) or in step f) already comprises an organic solvent (such as for example S03 and / or S04).

Step ii) above comprises in particular the addition of deionized water to the solution of the compound of formula (III) in the above-mentioned organic solvent S'1, to allow the dissolution of said of formula (III), and the extraction of said of formula (III) in water (aqueous phase).

The extraction can be carried out by any known extraction means. The extraction typically allows the separation of an aqueous phase (aqueous solution of said salt in the present case) and an organic phase.

According to the invention, step ii) can be repeated at least once, for example three times. In a first extraction, an amount of deionized water corresponding to half the mass of the initial solution can be added, then an amount equal to approximately 1/3 of the mass of the initial solution during the second extraction, then a quantity equal to approximately 1/4 of the mass of the initial solution during the third extraction.

Preferably, step ii) is such that the mass of deionized water is greater than or equal to one third, preferably greater than or equal to half, of the mass of the initial solution of the compound of formula (III) in the organic solvent S'1 (in the case of a single extraction, or for the first extraction only if step ii) is repeated at least once).

In case of multiple extractions (repetition of step ii)), the extracted aqueous phases can be combined together to form a single aqueous solution.

At the end of step ii), an aqueous solution of the compound of formula (III) is in particular obtained.

According to one embodiment, the mass content of the compound of formula (III) in the aqueous solution is between 5% and 35%, preferably between 10% and 25%, relative to the total mass of the solution.

Preferably, step g) comprises a concentration step iii) between step ii) and step iv), preferably in order to obtain an aqueous solution of the compound of formula (III) comprising a mass content of compound of formula (III) between 20% and 80%, in particular between 25% and 80%, preferably between 25% and 70%, and advantageously between 30% and 65% relative to the total mass of the solution. The concentration step can be carried out by a rotary evaporator under reduced pressure, at a pressure less than 50 mbar abs (preferably less than 30 mbar abs), and in particular at a temperature between 25 ° C and 60 ° C, preferably between 25 ° C and 500, preferably between 25 ° C and 40 ° C, for example at 40 ° C.

The compound of formula (III), contained in the aqueous solution obtained at the end of stage ii), and of a possible concentration stage iii) or of a possible other intermediate stage, can then be recovered by extraction. with an organic solvent S'2, said solvent S'2 preferably being able to form an azeotrope with water (step iv). Step iv) leads in particular, after extraction, to an organic phase, saturated with water, containing the compound of formula (III) (it is a solution of compound of formula (III) in the organic solvent S'2, said solution being saturated with water).

The extraction typically allows the separation of an aqueous phase and an organic phase (solution of the compound of formula (III) in the solvent S'2 in the present case).

Step iv) advantageously makes it possible to obtain an aqueous phase and an organic phase, which are separated.

Preferably, the organic solvent S'2 is chosen from the group consisting of esters, nitriles, ethers, carbonates, chlorinated solvents, aromatic solvents, and mixtures thereof. Preferably, the solvent S'2 is chosen from ethers, esters, and mixtures thereof. For example, mention may be made of diethylcarbonate, methyl-t-butyl ether, cyclopentylmethyl ether, ethyl acetate, propyl acetate, butyl acetate, dichloromethane, tetrahydrofuran, acetonitrile, diethyl ether, and mixtures thereof. Preferably, the solvent S'2 is chosen from methyl-t-butyl ether, cyclopentylmethyl ether, ethyl acetate, propyl acetate, butyl acetate, and mixtures thereof. In particular, the organic solvent S'2 is butyl acetate.

The extraction step iv) is repeated at least once, preferably from one to ten times, and in particular four times. The organic phases can then be combined into one before step v). For each extraction, the quantity by mass of organic solvent S'2 used can vary between 1/6 and 1 time the mass of the aqueous phase. Preferably, the organic solvent S'2 / water mass ratio, during an extraction in step iv), varies from 1/6 to 1/1, the number of extractions varying in particular from 2 to 10.

Preferably, during the extraction stage iv), the organic solvent S'2 is added to the aqueous solution resulting from stage ii) (and from optional stage iii).

Step g) according to the second embodiment can comprise a pre-concentration step between step iv) and step v), preferably to obtain a solution of the compound of formula (III) in the organic solvent S ′ 2 comprising a mass content of compound of formula (III) of between 20% and 60%, and preferably between 30% and 50% by mass relative to the total mass of the solution. The pre-concentration step can be carried out at a temperature ranging from 25 ° C to 60 ° C, preferably from 25 ° C to 45 ° C, optionally under reduced pressure, for example at a pressure lower than 50 mbar abs, in particular at a pressure below 30 mbar abs. The pre-concentration step is preferably carried out by a rotary evaporator under reduced pressure, in particular at 40 ° C. and at a pressure below 30 mbar abs.

According to the invention, the concentration step v) can be carried out at a pressure between 10 -2 mbar abs and 5 mbar abs, preferably between 5.10 -2 mbar abs and 2 mbar abs, preferably between 5.10 1 and 2 mbar abs, even more preferably between 0.1 and 1 mbar abs, and in particular between 0.4 and 0.6 mbar abs. In particular, step v) is carried out at 0.5 mbar abs or at 0.1 mbar.

According to one embodiment, step v) is carried out at a temperature between 30 ° C and 95 ° C, preferably between 30 ° C and 90 ° C, preferably between 40 ° C and 85 ° C, and in particular between 50 ° C and 70 ° C.

According to one embodiment, step v) is carried out with a residence time less than or equal to 15 min, preferably less than 10 min and preferably less than or equal to 5 minutes and advantageously less than or equal to 3 minutes.

In the context of the invention, and unless otherwise specified, the term “residence time” is understood to mean the time which elapses between the entry of the solution of the compound of formula (III) (in particular obtained at the end of of step iv) above) in the evaporator and the outlet of the first drop of the solution.

According to a preferred embodiment, the temperature of the condenser of the short path thin film evaporator is between -50 ° C and 5 ° C, preferably between -35 ° C and 5 ° C. In particular, the temperature of the condenser is -5 ° C.

The aforementioned short path thin film evaporators are also known under the name "Wiped film short path" (WFSP). They are typically called so because the vapors generated during evaporation make a “short path” (short distance) before being condensed in the condenser.

Among the short path thin film evaporators, mention may in particular be made of the evaporators sold by the companies Buss SMS Ganzler ex Luwa AG, UIC Gmbh or VTA Process.

Typically, short path thin film evaporators may have a solvent vapor condenser placed inside the apparatus itself (especially in the center of the apparatus), unlike other types of film evaporators. thin (which are not short-path) in which the condenser is located on the outside of the device.

In this type of device, the formation of a thin film of product to be distilled on the internal hot wall of the evaporator can typically be ensured by continuous spreading on the evaporation surface using mechanical means. specified below.

The evaporator can in particular be provided at its center with an axial rotor on which the mechanical means which allow the formation of the film on the wall are mounted. These may be rotors equipped with fixed blades: lobed rotors with three or four blades made of flexible or rigid materials, distributed over the entire height of the rotor, or else rotors equipped with mobile blades, vanes, wipers, guided wipers. In this case, the rotor can be constituted by a succession of pivot-articulated vanes mounted on a shaft or axis by means of radial supports. Other rotors can be equipped with mobile rollers mounted on secondary axles and said rollers are pressed against the wall by centrifugation. The speed of rotation of the rotor which depends on the size of the device, can be readily determined by those skilled in the art. The different mobiles can be made of various materials, metallic for example steel, alloy steel (stainless steel), aluminum, or polymeric, for example

polytetrafluroethylene PTFE or glass materials (enamel); metallic materials coated with polymeric materials.

Process

The method according to the invention can comprise intermediate steps between the various steps of the aforementioned method.

According to one embodiment, steps a), b), c), and optionally d), and e) are sequential.

According to one embodiment, the method according to the invention comprises:

- a step a) comprising the reaction of a sulfonamide of the following formula (A):

R 0 - (SO 2 ) -NH 2 (A)

in which 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 Fg, C 4 H 2 F 7 , C 4 H F 5, C5F1 1,

C6F13, C 7 F 15, C 8 F I 7 OR C 9 Fi 9, preferably R 0 representing OH;

with at least one sulfur-containing acid and at least one chlorinating agent, to form a compound of formula (I):

R I - (S0 2 ) -NH- (S0 2 ) -CI (I)

in which Ri 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 2J C 2 F 5 , C 3 F 7J C 3 H 4 F 3J C 3 HF 6 , C 4 F 9J C 4 H 2 F 7J C 4 H 4 F 5 , C5F1 1, CeF I3 , C 7 F 15, C 8 F I 7 OR C 9 F I 9,R I preferably representing Cl;

- a step b) of fluorination of a compound of formula (I) with anhydrous HF in the presence of at least one SOI organic solvent,

- a step c) of distillation of the composition obtained in step b) making it possible to form and recover

o a first stream F1 comprising HF, the organic solvent SOI and optionally HCl, preferably at the top of the distillation column, said stream being gaseous or liquid;

o a second stream F2 comprising the compound of formula (II) above, and optionally heavy compounds, preferably at the bottom of the distillation column, said stream F2 preferably being liquid;

- an optional step d) of dissolving the composition obtained in step b) and comprising a compound of formula (II) (stream F2), in an organic solvent SO2;

a step e) of contacting the composition obtained in step c) comprising a compound of formula (II) above (stream F2), with a composition, preferably aqueous, comprising at least one alkali or alkaline metal salt - earthy, to obtain a compound of formula (III) as defined above.

The process according to the present invention is particularly advantageous for manufacturing the following compounds of formula (III): LiN (S0 2 F) 2 , LiNS0 2 CF 3 S0 2 F, UNS0 2 C 2 F 5 S0 2 F, UNS0 2 CF 2 0CF 3 S0 2 F, UNS0 2 C 3 HF 6 S0 2 F, LiNS0 2 C 4 F 9 S0 2 F, LiNS0 2 C 5 FiiS0 2F, UNS0 2 C 6 F I3 S0 2 F, LiNS0 2 C 7 F 15 S0 2 F, LiNS0 2 C 8 F 17 S0 2 F, LiNS0 2 C 9 F 19 S0 2 F, NaN (S0 2 F) 2 , NaNS0 2 CF 3 S0 2 F, NaNS0 2 C 2 F 5 S0 2 F, NaNS0 2 CF 2 0CF 3S0 2 F, NaNS0 2 C 3 HF 6 S0 2 F, NaNS0 2 C 4 F 9 S0 2 F, NaNS0 2 C 5 F 1 1 S0 2 F, NaNS0 2 C 6 F 13 S0 2 F, NaNS0 2 C 7 F 15 S0 2 F, NaNS0 2 C 8 F 17 S0 2 F, NaNS0 2 C 9 F 19S0 2 F KN (S0 2 F) 2 , KNS0 2 CF 3 S0 2 F, KNS0 2 C 2 F 5 S0 2 F, KNS0 2 CF 2 0CF 3 S0 2 F, KNS0 2 C 3 HF 6 S0 2 F, KNS0 2 C 4 F 9 S0 2 F, KNS0 2 C 5 F H S0 2 F,

KNSO 2 C 6 F 13 SO 2 F, KNSO 2 C 7 F 15 SO 2 F, KNSO 2 C 8 F 17 SO 2 F and KNSO 2 C 9 F 19 SO 2 F.

Preferably, the process according to the invention is a process for preparing LiN (S0 2 F) 2 (LiFSI).

In the context of the invention, the terms “lithium salt of bis (fluorosulfonyl) imide”, “lithium bis (sulfonyl) imide”, “LiFSI”, “LiN (S0 2 F) 2” , are used in an equivalent manner , "Lithium bis (sulfonyl) imide", or "lithium bis (fluorosulfonyl) imide".

The process according to the invention advantageously leads to a compound of formula (III), and in particular to LiFSI, having a high purity, in particular at least equal to 99.5% by weight, advantageously at least equal to 99.95% in weight. In the context of the invention, the term “ppm” is understood to mean ppm by weight.

Uses

The present invention also relates to the use of the compound obtained by the process according to the invention, in Li-ion batteries, in particular in electrolytes of Li-ion batteries.

In particular, they can be Li-ion batteries for portable devices (for example mobile phones, cameras, tablets or laptops), or electric vehicles, or renewable energy storage (such as than photovoltaic or wind power).

In the context of the invention, by “between x and y”, or “ranging from x to y”, is meant an interval in which the limits x and y are included. For example, the temperature “between -20 and 80 ° C” notably includes the values ​​-20 ° C and 80 ° C.

All of the embodiments described above can be combined with each other. In particular, each embodiment of any step of the method of the invention can be combined with another particular embodiment.

The following examples make it possible to illustrate the invention without, however, limiting it.

EXAMPLE:

Example 1: preparation of bis (fluorosulfonyl) imide (HFSI)

In a stirred autoclave coated with a PFA jacket, fitted with a gas introduction tube and connected to a bubbler to trap coproduced HCl, 107 g of bis (chlorosulfonyl) imide (HCISI) are dissolved in 320 g of acetate of butyl. The mixture is brought with stirring. 25 g of HF are introduced through the introduction tube (ie an HF / HCISI molar ratio equal to 2.5) over 1 hour 30 minutes. The reaction is weakly exothermic. The temperature of the reaction medium goes from 18 ° C to 29 ° C during handling. At the end of the induction, a stream of nitrogen is passed in order to strip the excess HF.

The mixture obtained is introduced into a reactor fitted with a vacuum distillation column connected to a dry ice trap. The pressure is adjusted to 12 mbar. We're starting to heat up. A first distillation fraction is obtained between room temperature and 36 ° C (vapor temperature). A second fraction distils between 48 ° C and 57 ° C. The distillation is then stopped.

This second fraction consists of bis (fluorosulfonyl) imide (HFSI) (NMR analysis) at 99% purity and represents 53 g, ie a yield of 58%.

The NMR analysis conditions of the fluorinated species in 19 F, H1 NMR are as follows:

The NMR spectra and quantifications were carried out on a Bruker AV 400 spectrometer, at t 376.47 MHz for 19 F, on a 5 mm probe of BBFO + type .

Example 2: preparation of the lithium salt of bis (fluorosulfonyl) imide (LiFSI)

40 g of HFSI from Example 1 (0.22 mol) are taken up in 60 g of butyl acetate. 9.2 g of solid Li 2 C0 3 (0.12 mol) are introduced into a stirred and thermostated reactor fitted with a temperature probe . Allowed to react for 4 hours while controlling the neutralization temperature below 15 ° C.

At the end of neutralization, the reaction medium is recovered which is filtered to remove the excess lithium carbonate. The cake is washed with 100 ml of butyl acetate.

LiFSI is recovered in solution, the NMR analysis of which does not detect cleavage products and the ion chromatography analysis of which does not detect sulfate, potassium or sodium.

CLAIMS

1. Process for preparing a compound of the following formula (III):

R 2 - (S0 2 ) -NM- (S0 2 ) -F (III)

in which :

- 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 Fg, C 4 H 2 F 7 , C 4 H 4 F5 , C 5 F 11 , CeF 13 , C 7 F 15 , C 8 F 17 OR

C9F19, preferably R 2 representing F;

- M represents a monovalent or divalent cation;

said method comprising:

- a step b) of fluorination of a compound of formula (I) below:

Rr (S0 2 ) -NH- (S0 2 ) -CI (I)

in which Ri represents one of the following radicals: Cl, F, CF 3 , CHF 2 , CH 2 F, C 2 HF, C 2 H 2 F 3 , C 2 H 3 F 2 , C 2 F 5 , C 3 F 7J C 3 H F 3 , C 3 HF 6 , C 4 Fg, C 4 H 2 F 7 , C 4 H F 5 , C5F1 1,

C 6 F I 3 , C 7 F 15 , C 8 F I 7 OR C 9 F 19, Ri preferably representing Cl;

with at least one fluorinating agent, preferably in the presence of at least one SOI organic solvent;

- a step c) of distilling the composition obtained in step b), said composition comprising a compound of following formula (II):

R 2 - (S0 2 ) -NH- (S0 2 ) -F

2. Method according to claim 1, wherein the fluorinating agent is selected from the group consisting of HF (preferably anhydrous HF), KF, AsF 3 , BiF 3 , ZnF 2 , SnF 2 , PbF 2 , CUF 2 , and mixtures thereof, the fluorinating agent preferably being HF.

3. Method according to any one of claims 1 to 2, further comprising a step a), prior to step b), comprising the reaction of a sulfonamide of formula (A) below:

R 0 - (SO 2 ) -NH 2 (A)

in which 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 Fg, C 4 H 2 F 7 , C 4 H F 5 , C 5 F 11 , C 3 F I3 , C 7 F 15, C S FI 7 OR C 9 F 19 ;

with at least one sulfur acid and at least one chlorinating agent, to form a compound of formula (I) as defined in claim 1.

4. Method according to any one of claims 1 to 3, comprising a step d) of dissolving the composition obtained in step b) or in step c) in an organic solvent SO2.

5. Method according to any one of claims 1 to 4, further comprising a step e) of bringing the composition obtained in step c) or in step d) into contact with a composition comprising at least one salt of alkali metal or alkaline earth metal, making it possible to lead to a compound of formula (III).

6. The method of claim 5, further comprising a cation exchange step f) to convert a compound of formula (III) into another compound of formula (III), but for which M is different.

7. Process according to any one of claims 1 to 6, in which step c) of distilling the composition obtained in step b) makes it possible to form and recover: a. a first stream F1 comprising HF, optionally the organic solvent SOI, and / or optionally HCl, preferably at the top of the distillation column, said stream F1 being gaseous or liquid;

b. a second stream F2 comprising the compound of formula (II), and optionally heavy compounds, preferably at the bottom of the distillation column, said stream F2 preferably being liquid.

8. The method of claim 7, wherein the stream F2 is subjected to a distillation step in a second distillation column, to form and recover:

o a stream F2-1 comprising the compound of formula (II) free from heavy compounds at the top of the second distillation column, said stream F2-1 preferably being liquid,

o a stream F2-2 comprising the heavy compounds and the compound of formula (II), at the bottom of the second distillation column, said stream F2-2 containing less than 10% by weight of the compound of formula (II) contained in the composition obtained in step b), preferably less than 7% by weight, and

preferably less than 5% by weight, said flow F2-2 preferably being liquid.

9. Method according to any one of claims 1 to 8, wherein step c) of distilling the composition obtained in step b) makes it possible to form and recover: o a first stream F′1 comprising HF, optionally. the organic solvent SOI and / or optionally HCl, preferably at the top of the distillation column, said stream F'1 being gaseous or liquid;

o a second stream F'2 comprising the compound of formula (II), preferably recovered by lateral withdrawal, said stream F'2 preferably being liquid; o a third stream F'3 comprising heavy substances and the compound of formula (II), preferably at the bottom of the distillation column, said stream F'3 containing less than 10% by weight of the compound of formula (II) contained in the composition obtained in step b), preferably less than 7% by weight, and preferentially less than 5% by weight, said stream F′3 preferably being liquid.

10. A method according to any one of claims 1 to 9, wherein step c) of distillation is carried out at a pressure ranging from 0 to 5 bar abs, preferably from 0 to 3 bar abs, and preferably from 0 to 1 bar abs.

1 1. A method according to any one of claims 1 to 10, wherein step c) of distillation is carried out:

o at a temperature at the bottom of the distillation column ranging from 150 ° C to 200 ° C, preferably from 160 ° C to 180 ° C, and preferably from 165 ° C to 175 ° C, at a pressure of 1 bar abs; or

o at a temperature at the bottom of the distillation column ranging from 30 ° C to 100 ° C, preferably from 40 ° C to 90 ° C, and preferably from 40 ° C to 85 ° C, at a pressure of 0.03 bar abs.

12. A method according to any one of claims 5 to 10, wherein the alkali or alkaline earth metal salt is selected from the group consisting of MOH, M0H, H 2 0, MHCOs, M2CO3, MCI, M (OH) 2 , M (0H) 2, H 2 0, M (HC0 3 ) 2, MCOS, MCI2, and mixtures thereof, M being as defined in claim 1, the alkali or alkaline earth metal salt preferably being chosen from the group consisting of LiOH, Li0H, H 2 0, LiHCOs, Li 2 C0 3 , LiCl, KOH, K0H, H 2 0, KHC0 3 , K 2 C0 3 , KOI, NaOH, Na0H, H 2 0,

NaHCO 3 , Na 2 CO 3 , NaCl, and mixtures thereof, the salt preferably being a potassium salt, and advantageously K2CO3.

13. A method according to any one of claims 5 to 12, wherein:

the composition comprising at least one alkali or alkaline earth metal salt is an aqueous composition, preferably an aqueous suspension or an aqueous solution.

o the composition comprising at least one alkali or alkaline earth metal salt is a solid composition, preferably the composition consists of at least one alkali or alkaline earth metal salt

14. Method according to any one of claims 5 to 13, wherein step e) is carried out at a temperature less than or equal to 40 ° C, preferably less than or equal to 30 ° C, preferably less than or equal to 20. ° C, and in particular less than or equal to 15 ° C.

15. Process according to any one of claims 1 to 14, further comprising a step g) of purification of the compound of formula (III).

16. Use of the compound of formula (III) obtained according to the process as defined according to any one of claims 1 to 15, in a Li-ion battery, in particular in an electrolyte of a Li-ion battery.