WO2019229357A1

WO2019229357A1 - Process for preparing imide salts containing a fluorosulfonyl group

Info

Publication number: WO2019229357A1
Application number: PCT/FR2019/051235
Authority: WO
Inventors: Grégory Schmidt; Dominique Deur-Bert; Rémy Teissier
Original assignee: Arkema France
Priority date: 2018-06-01
Filing date: 2019-05-28
Publication date: 2019-12-05
Also published as: FR3081867B1; FR3081867A1

Abstract

The present invention relates to a process for preparing a compound of formula (III):: R₂-(SO₂)-N Li-(SO₂)-F, said process comprising: - a step b) comprising: a step b1) of fluorination of a compound of following formula (I): R₁-(SO₂)-NH-(SO₂)-Cl in which R₁ is one of the following radicals: Cl, F, CF3, CHF₂, CH₂F, C₂HF₄, C₂H₂F₃ _, C₂H₃F_2, C₂F₅, C3F7, C₃H₄F_3, C₃HF₆, C₄F_9, C₄H₂F_7, C₄H₄F₅, C₅F_11, C₆F_13, C₇F_15, C₈F₁₇ or C₉F_19, R₁ preferably being Cl, with at least one fluorinating agent, in the presence of at least one organic solvent SO1; - a step c) comprising the addition of the composition obtained in step b), said composition comprising a compound of the following formula (II): R₂-(SO₂)-NH-(SO₂)-F to a composition comprising at least one lithium salt.

Description

PROCESS FOR PREPARING SALT OF IMIDES CONTAINING A GROUP

fluorosulfonyl

FIELD OF THE INVENTION

The present invention relates to a process for the preparation of lithium salts of imides containing a fluorosulfonyl group.

TECHNICAL BACKGROUND

Anions of sulfonylimide type, by 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. As the battery market is booming and the reduction of battery manufacturing costs becomes a major issue, a large-scale and low-cost synthesis process for this type of anion is necessary.

In the specific field of Li-ion batteries, the salt currently most used is LiPF ₆ but this salt shows numerous disadvantages such as limited thermal stability, sensitivity to hydrolysis and therefore lower battery safety. . Recently, new salts having the FSO 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 (FSO ₂ ) ₂ ) has shown very interesting properties that make it a good candidate to replace LiPF ₆ .

There are various processes for preparing LiFSI. WO2009 / 123328 describes in particular the preparation of LiFSI from bis (chlorosulfonyl) imide, via various stages of preparation of intermediate salts, such as for example a zinc salt of bis (fluorosulfonyl) imide, followed by an ammonium salt bis (fluorosulfonyl) imide.

Most existing methods include many steps, resulting in forming side products with physical properties such that their removal can be complex, and / or require expensive purification steps. In addition, the accumulation of steps can lead to a decrease in the final yields of LiFSI. In addition, some processes are not applicable on an industrial scale.

There is therefore still a need for a process for the preparation of bis (fluorosulfonyl) imide lithium salt not having the abovementioned disadvantages. DESCRIPTION OF THE INVENTION

The present invention relates to a process for preparing a compound of formula (III) below:

R ₂ - (S0 ₂₎ Li -N (S0 ₂₎ -E (III) 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, C3F7, C3H4F3, C3HF6, C4F9, C4H ₂ F7, C4H4F5, C5F11, C6F13, C7F15, C9F19 or CeFi7, preferably R ₂ is F;

said process comprising:

a step b) comprising:

a step b1) of fluorination of a compound of formula (I) below: R _I - (S0 ₂ ) -NH- (S0 ₂ ) -CI (I) in which R 1 represents one of the following radicals: Cl, F, CF _3, CHF _2, CH ₂ F, C ₂ HF4, C ₂ H ₂ F 3, C ₂ H3F _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 F7, C ₄ H ₄ F _5, C ₅ F _11, C6F13, C7F15, C9F19 C ₈ Fi.7 OR, R preferably representing Cl; with at least one fluorinating agent, in the presence of at least one SOI organic solvent;

o a possible step b2) of distillation of the composition obtained in step b1);

o a possible step b3) of dissolving the composition obtained in step b1 or in step b2), in an organic solvent S02;

a step c) comprising adding the composition obtained in step b), said composition comprising a compound of formula (II) below:

R ₂ - (S0 ₂ ) -NH- (S0 ₂ ) -F (II), in a composition comprising at least one lithium salt.

Preferably, the present invention relates to a process for preparing a compound of formula (III) below:

R ₂ - (S0 ₂ ) -N Li- (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 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, CeF17 or C9F19, preferably R2 being F;

said method comprising:

a step a) comprising the reaction of a sulphonamide of formula (A) below:

RO - (S0 ₂ ) -NH ₂ (A) wherein Ro 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, C4F9, C4H2F7, C4H4F5, C5F11, C6F13, C ₇ F 1 _5, C ₈ C ₉ OR ₇ Fi F1 _9, preferably Ro represents OH;

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

R _I - (S0 ₂ ) -NH- (S0 ₂ ) -CI (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 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 ₇ OR C ₉ F _9, R 1 preferably representing Cl;

a step b) comprising: a step b1) of fluorination of said compound of formula (I) with at least one fluorinating agent, in the presence of at least one SOI organic solvent; o a possible step b2) of distillation of the composition obtained in step b1);

o a possible step b3) of dissolving the composition obtained in step b1 or in step b2) in an organic solvent SO2; a step c) comprising adding the composition obtained in step b), said composition comprising a compound of formula (II) below:

R ₂ - (SO 2) -NH- (SO ₂ ) -F (II), in a composition comprising at least one lithium salt.

The process according to the invention advantageously makes it possible to remedy at least one of the disadvantages of the existing processes. It advantageously allows:

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

o 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.

Step a) chlorination

According to one embodiment, the aforementioned method further comprises a step a), prior to step b), comprising the reaction of a sulfamide of formula (A) below:

RO - (S0 ₂ ) -NH ₂ (A) in which Ro 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 ₆ , C ₄ H ₂ F ₇ , C ₄ H ₄ Fs, C ₅ F 11, CeF ₃ C ₇ FI _S , C _S FI ₇ OR C9F19;

with at least one sulfuric 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 Ro is OH.

Step a) can be performed:

at a temperature between 30 ° C and 150 ° C; and or

o with a reaction time 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 may be selected from the group consisting of chlorosulfonic acid (CIS0 ₃ H), sulfuric acid, oleum, and mixtures thereof.

According to the invention, the chlorinating agent may be selected from the group consisting of thionyl chloride (SOCI ₂ ), oxalyl chloride (COCI) ₂ , phosphorus pentachloride (PCI5), 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 sulfuric acid and the compound (A) (in particular in which Ro = OH) may 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) may be between 2 and 10, preferably between 2 and 5. In particular, when the sulfur-containing agent is chlorosulphonic acid, the molar ratio between this and the compound (A) (in particular in which Ro = OH) is between 0.9 and 5, and / or the The molar ratio between the chlorinating agent and the compound (A), in particular with Ro = OH, is between 2 and 5.

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

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

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

RI- (S0 ₂ ) -NH- (S0 ₂ ) -CI (I)

wherein R 1 is as defined above, and in particular wherein R 1 is Cl.

The method according to the invention comprises a step b) comprising: a step b1) of fluorination of a compound of formula (I) below:

RI- (S0 ₂₎ -NH- (S0 ₂₎ -Cl (I) wherein 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 _S 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, R 1 being preferably Cl; with at least one fluorinating agent, in the presence of at least one SOI organic solvent;

o a possible step b2) of distillation of the composition obtained in step b1);

o a possible step b3) of dissolving the composition obtained in step b1) or in step b2) in an organic solvent S02.

Step b1)

Step b1) in particular allows 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 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, CeF or C9F19, preferably R2 representing F.

Preferably, in formula (II) above, R2 is F, CF ₃ , CHF 2, or CH 2 F. It is particularly preferred that R2 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 mixtures thereof. the fluorinating agent is preferably HF, and even more preferably anhydrous HF.

In the context of the invention, "anhydrous HF" means THF containing less than 500 ppm water, preferably less than 300 ppm water, preferably less than 200 ppm water.

Step b1) of the process is carried out in at least one SOI organic solvent. The organic solvent SOI 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 organic solvent SOI, there may be mentioned in particular esters, nitriles, dinitriles, ethers, diethers, amines, phosphines, and mixtures thereof.

Preferably, the organic solvent SOI 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, diethylisopropylphosphine, and mixtures thereof. In particular, the organic solvent SOI is dioxane.

Step b1) may be carried out at a temperature between 0 ° C. and the boiling temperature of the organic solvent SOI (or of the mixture of organic solvents SOI). Preferably, step b) is carried out at a temperature of between 5 ° C. and the boiling temperature of the organic solvent SOI (or the mixture of organic solvents SOI), preferably between 20 ° C. and the boiling temperature of SOI organic solvent (or SOI organic solvent mixture).

Step b1), preferably with anhydrous hydrofluoric acid, may be carried out at a pressure P, preferably between 0 and 16 bar abs. This step b1) is preferably carried out by dissolving the compound of formula (I) in the organic solvent SOI, or the mixture of organic solvents SOI, prior to the reaction step with the fluorinating agent, preferably with anhydrous HF.

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

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

The molar ratio x between the fluorinating agent, preferably 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 HF, can be carried out in a closed medium or in an open medium, preferably step b) is carried out in an open medium, in particular with the release of HCl in the form of gas.

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

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

The composition obtained at the end of step b1) can be stored in a container resistant to HF.

The composition obtained in step b1) may comprise HF (it is in particular unreacted HF), the compound of formula (II) mentioned above, the SOI solvent (such as, for example, dioxane), and optionally HCl, and / or possibly heavy compounds.

Step b2)

According to one embodiment, step b) comprises a step b2) of distillation of the composition obtained in step b1).

According to one embodiment, the distillation step b2) of the composition obtained in step b1) makes it possible to form and recover:

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

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 being preferably liquid. When the stream F2 comprises heavy compounds, this can be subjected to a further distillation step in a second distillation column, to form and recover: a stream F2-1 comprising the compound of formula (II) free of compounds heavy, preferably at the top of the distillation column, said stream F2-1 being preferably liquid, a stream F2-2 comprising the heavy compounds and the compound of formula (II), preferably at the bottom of the distillation column, said F2-2 stream containing less than 10% by weight of the compound of formula (II) contained in the composition obtained in step b1), preferably less than 7% by weight, and preferably less than 5% by weight, said stream F2-2 being preferably liquid.

According to one embodiment, step b2) of distillation of the composition obtained in step b1) makes it possible to form and recover, thanks to the use of two distillation columns: a first stream F1 comprising HF, the solvent organic SOI and optionally HCl at the top of the first distillation column, said stream F1 being gaseous or liquid;

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

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 b1), preferably less than 7% by weight, and preferably less than 5% by weight, said flux F2-2 preferably being liquid.

In the context of the invention, the term "heavy compounds", organic compounds having a boiling point greater than that of the compound of formula (II). They can result from cleavage reactions of the compound of formula (I) leading for example to compounds such as FSO2NH2, and / or solvent degradation reactions leading to the formation of oligomers. According to one embodiment, the distillation step b2) of the composition obtained in step b1) makes it possible to form and recover:

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

a second stream F'2 comprising the compound of formula (II), preferably recovered by lateral withdrawal, said stream F'2 being preferably liquid; a third stream F'3 comprising heavy metals 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 b1), preferably less than 7% by weight, and preferably less than 5% by weight, said flux F'3 preferably being liquid.

To carry out the side racking, the distillation column may contain at least one tray.

The distillation step b2) 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.

The distillation step b2) can be carried out:

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 preferentially from 165 ° C. to 175 ° C., at a pressure of 1 bar abs; or

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 preferentially from 40 ° C. to 85 ° C., at a pressure of 0.03 bar abs.

The distillation step b2) 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 may comprise:

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

and or o trays such as for example perforated trays, fixed valve trays, trays movable valves, trays caps, or combinations thereof.

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

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

The corrosion-resistant materials can be selected from enamelled steels, nickel, titanium, chromium, graphite, silicon carbides, nickel-based alloys, cobalt-based alloys, alloy-based alloys, chromium, steels coated partially or totally with a fluoropolymer protective coating (such as for example PVDF: polyvinylidene fluoride, PTFE: polytetrafluoroethylene, PFA: copolymer of C2F4 and perfluorinated vinyl ether, FEP: C2F4 copolymer and C3F6 _{, ie} 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. For example, mention may be made of Inconel®, Hastelloy® or Monel® alloys.

Flows F1 and F'1 can comprise HF, HCl, SOI organic solvent (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 F1 flux, 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 F1 flux.

According to one embodiment, the flow 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 F'1 flux, and from 30% to 98% by weight. % by weight of organic solvent SOI, preferably from 40% to 95% by weight of SOI, relative to the total weight of the flow 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 stream F2. According to one embodiment, the flow 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 b2) 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 a high purity, without requiring additional purification steps.

Step b3)

According to one embodiment, step b) comprises a step b3) of dissolving the composition obtained in step b1) or in step b2) in an organic solvent SO2, said solvent SO2 being preferably aprotic polar .

The organic solvent S02 may be a water-miscible solvent.

In the context of the invention, the term "solvent miscible with water", a solvent does not form a macroscopic phase separation.

The organic solvent SO2 may be selected from the group consisting of ethers, diethers, nitriles, amines, carbonates or phosphines. Preferably, the organic solvent S02 is selected from the group consisting of methyl acetate, ethyl acetate, butyl acetate, acetonitrile, propionitrile, isobutyronitrile, glutaronitrile , dioxane, tetrahydrofuran, triethylamine, tripropylamine, diethylisopropylamine, pyridine, diethylcarbanoate, dimethylcarbonate, methylethylcarbonate, ethylene carbonate, trimethylphosphine, triethylphosphine, diethylisopropylphosphine, and mixtures thereof. the SO2 solvent being preferentially dioxane.

Preferably, step b3) comprises the addition of said solvent SO2 in the composition obtained in step b1) or in step b2).

Preferably, step b) comprises step b1), step b2) and step b3).

In the embodiment where step b) comprises step b1), b2) and b3), step b3) comprises, in particular, dissolving the stream F2 (or the stream F2-1 or the stream F '). 2) in an organic solvent S02. The aforementioned method comprises a step c) comprising adding the composition obtained in step b), said composition comprising a compound of formula (II) below:

R ₂ - (S0 ₂ ) -NH- (S0 ₂ ) -F (II),

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

in a composition comprising at least one lithium salt.

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

R ₂ - (S0 ₂ ) -NLi- (S0 ₂ ) -F (III) 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, C3F7, C3H4F3, C3HF6, C4F9, C4H ₂ F7, C4H4F5, C5F11, C6F13, C7F15, C9F19 or CeFi7, R ₂ is preferably F.

Typically, step c) can be carried out from the composition obtained in step b1) or from the composition obtained in step b2) (flux F2, or flow F2-1 or flow F'2) or from the composition obtained in step b3) or after any intermediate step between step b) and step c).

According to one embodiment, the composition comprising at least one lithium salt is an aqueous composition, preferably an aqueous suspension or an aqueous solution.

According to another embodiment, the composition comprising at least one lithium salt is a solid composition, preferably the composition consists of at least one solid lithium salt.

In particular, the composition obtained in step b) is added to a container comprising the composition comprising at least one lithium salt. The container may be a reactor, preferably comprising at least one stirring system. The elements making it possible to introduce the composition obtained in step b) are preferably resistant to HF.

According to one embodiment, the lithium salt is selected from the group consisting of LiOH, LiOH, H ₂ O, L ₁ HCO ₃ , Li ₂ CC ₃ , LiCl, and mixtures thereof. Preferably, the lithium salt is Li ₂ CC> 3.

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

Preferably, the aforementioned method comprises a step c) comprising adding the composition obtained in step b), said composition comprising a compound of formula (II) mentioned above:

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 lithium salt.

To determine the amount of lithium 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 c) is such that:

the molar ratio of the lithium 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 lithium 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, salt I_i ₂ CC> 3 has a number of basicities equal to 2.

Step c) of the process according to the invention may be carried out at a temperature of 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 at 15 ° C.

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

The compound of formula (III) prepared may 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 SO 3 typically poorly 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 stated, "poorly soluble in water" means a solvent whose solubility in water is less than 5% by weight.

The organic solvent SO 3 mentioned above 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 and diethyl ether, and mixtures thereof. In particular, the organic solvent SO 3 is butyl acetate.

For each extraction, the mass quantity of organic solvent used can vary between 1/6 and 1 times the weight 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 mass content of compound of formula (III) ranging from 5% to 40% by weight.

The separated organic phase (obtained after 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 weight, concentration that can be achieved by any means of evaporation known to those skilled in the art.

The aforementioned cake G can be washed with an organic solvent S04 selected from the following families: esters, nitriles, ethers, chlorinated solvents, aromatic solvents, and mixtures thereof. Preferably, the organic solvent SO 4 is chosen from dichloromethane, ethyl acetate, butyl acetate, tetrahydrofuran, acetonitrile, diethyl ether, and mixtures thereof. In particular, the organic solvent SO 4 is butyl acetate.

The mass quantity of organic solvent S04 used may vary between 1 and 10 times the weight of the cake. The total quantity of organic solvent SO4 intended for the washing may be used at once or in several times, in particular in order to optimize the dissolution of the compound of formula (III).

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

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 weight. said concentration can be 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 the washing (s) of the cake G, can be collected together, before the concentration step. Step d) Purification

The process according to the invention may further comprise a step of purifying the compound of formula (III) mentioned above.

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

At the end of step c) mentioned above, the compound of formula (III) may 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 d) is a crystallization step of the compound of formula (III) mentioned above.

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

Preferably, during step d), 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 compounds, such as, for example, toluene, in particular at a temperature of less than or equal to 25.degree. 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 c) can be concentrated to obtain a solution corresponding to the aforementioned composition. Concentration can be done by any conventional means of concentration. It can in particular be carried out under reduced pressure of between 40mbars and 0.01 mbar at a temperature below 70 ° C, preferably below 50 ° C, preferably below 40 ° C. It can be preferably performed according to the conditions of step v) described below.

Preferably, when the process according to the invention comprises the above-mentioned step b2), the process comprises a step d) of crystallization of the compound of formula (III) according to this first embodiment.

According to a second embodiment, step d) 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 above-mentioned compound of formula (III), forming an aqueous solution of said compound of formula (III); iii) optional concentration of said aqueous solution of said compound of formula

(ni) ^;

iv) extracting 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) concentrating the compound of formula (III) by evaporation of said organic solvent S'2 and 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 preferably less than or equal to 5 min;

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

Step d) may not comprise step i) mentioned above, if the compound of formula (III) obtained in step c) already comprises an organic solvent (such as, for example, SO 3 and / or SO 4).

Preferably, the method comprises this purification step d) according to this second embodiment, when the method according to the invention does not comprise step b2) mentioned above.

The above-mentioned step ii) comprises in particular the addition of deionized water to the solution of the compound of formula (III) in the abovementioned 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 this 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, a quantity of deionized water corresponding to half of the mass of the initial solution can be added, then an amount equal to about 1/3 of the mass of the initial solution during the second extraction, then a amount equal to about 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 solution. initial 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 compound of formula (III) is obtained in particular.

According to one embodiment, the mass content of 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 d) comprises a step of concentration iii) between step ii) and step iv), preferably 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 of less than 50 mbar abs (preferably less than 30 mbar abs), and in particular at a temperature of between 25 ° C and 60 ° C, preferably between 25 ° C and 50 ° C, 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 step ii), and of a possible concentration step iii) or of any other intermediate step, can then be recovered by extraction. with an organic solvent S'2, said solvent S'2 being able to form preferably an azeotrope with water (step iv). Stage iv) of the conduit, in particular, after extraction, with 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).

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

Preferably, the organic solvent S'2 is selected from the group consisting of esters, nitriles, ethers, 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, cyclopentyl methyl 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 and 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 mass quantity of organic solvent used can vary between 1/6 and 1 times the mass of the aqueous phase. Preferably, the mass ratio organic solvent S'2 / water, during an extraction of step iv), varies from 1/6 to 1/1, the number of extractions varying in particular from 2 to 10.

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

Step d) according to the second embodiment may 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 weight relative to the total mass of the solution. The pre-concentration step may 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 of less than 50 mbar abs, in particular at a pressure of less than 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 of less than 30 mbar abs.

According to the invention, step v) concentration can be carried out at a pressure between 10 ^-2 mbar and 5 mbar abs abs, preferably between 5.10 and ² mbar abs 2 mbar abs, preferably between 5.10 ¹ and 2 mbar abs, 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 of 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 of less than or equal to 15 minutes, preferably less than 10 minutes, 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 stated, the term "residence time" means the time that 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 as "Wiped film short path" (WFSP). They are typically so called because the vapors generated during evaporation make a "short trip" (short distance) before being condensed to the condenser.

Among the short-path thin film evaporators, there may be mentioned evaporators marketed by the companies Buss SMS Ganzler ex Luwa AG, UIC Gmbh or VTA Process.

Typically, short-path thin-film evaporators may include a solvent vapor condenser positioned within the apparatus itself (particularly in the center of the apparatus), unlike other types of film evaporators. thin (which are not short path) in which the condenser is located outside the device.

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

The evaporator may in particular be provided at its center, an axial rotor on which are mounted the mechanical means that allow the formation of the film on the wall. They may be rotors equipped with fixed blades: three-blade or four-blade lobed rotors in flexible or rigid materials, distributed over the entire height of the rotor or rotors equipped with moving blades, pallets, scrapers, guided rubbers. In this case, the rotor may be constituted by a succession of articulated pallets on pivot mounted on a shaft or axis via radial supports. Other rotors may be equipped with mobile rollers mounted on secondary axes and said rollers are pressed on the wall by centrifugation. The rotational speed of the rotor which depends on the size of the apparatus can be readily determined by those skilled in the art. The various mobiles can be made of various materials, for example metal, steel, alloy steel (stainless steel), aluminum, or polymers, for example polytetrafluoroethylene PTFE or glass materials (enamel); metallic materials coated with polymeric materials.

Process

The method according to the invention may comprise intermediate steps between the various steps of the aforementioned process. According to one embodiment, the steps a), b), c), and optionally d), are sequential.

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

a step a) comprising the reaction of a sulphonamide of formula (A) below:

RO - (S0 ₂ ) -NH ₂ (A) wherein Ro 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 ₈ 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 ₇ OR C ₉ F ₁₉ . preferably Ro representing OH;

R _I - (S0 ₂ ) -NH- (S0 ₂ ) -CI (I)

in which 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 ₈ F ₂ , C ₂ F ₅ , C ₃ F ₇ , C3H4F3, C3HF6, C4F9, C4H ₂ F7, C4H4F5, C5F11, CEFIS, C7F15, C ₈ Fi ₇ or C ₉ F _19, R preferably representing Cl;

a step b) comprising:

a step b1) of fluorination of a compound of formula (I) with anhydrous HF in the presence of at least one SOI organic solvent,

a step b2) of distillation of the composition obtained in step b1) for forming and recovering

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;

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

a step c) comprising adding the composition obtained in step b2) comprising a compound of formula (II) mentioned above (flux F2), in a composition, preferably aqueous, comprising at least one lithium salt.

According to a preferred embodiment, the method according to the invention comprises:

a step a) comprising the reaction of a sulphonamide of formula (A) below:

R _O - (S0 ₂ ) -NH ₂ (A) wherein Ro 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 F1 ₅ , C ₈ F ₇ OR C ₉ F _9, preferably Ro representing OH;

R _I - (S0 ₂ ) -NH- (S0 ₂ ) -CI (I)

a step b) comprising:

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;

a step b3) of dissolving the composition obtained in step b2) and comprising the compound of formula (II) (flux F2), in an organic solvent SO2;

a step c) comprising adding the composition obtained in step b3) comprising a compound of formula (II) mentioned above, in a composition, preferably aqueous, comprising at least one lithium salt.

The process according to the present invention is particularly advantageous for producing the following compounds of formula (III): LiN (SC ₂ F) ₂ , L ₁ NSO ₂ CF ₃ SO ₂ F, UNSO ₂ C ₂ F ₅ SO ₂ F, UNSO ₂ CF ₂ OCF ₃ SO ₂ F, UNSO ₂ C ₃ HF ₆ SO ₂ F, UNSO ₂ C ₄ F ₉ SO ₂ F, UNSO ₂ C ₅ F ₁₁ SO ₂ F, UNSO ₂ C ₆ F ₁₃ SO ₂ F, UNSO ₂ C ₇ F ₁₅ SO ₂ F, LiNSO ₂ C ₈ Fi ₇ S0 ₂ F and UNSO ₂ C ₉ F ₁₉ SO ₂ F.

Preferably, the process according to the invention is a process for the preparation of LiN (SO ₂ F) ₂ (LiFSI).

In the context of the invention, the terms "lithium salt of bis (fluorosulfonyl) imide", "lithium bis (sulfonyl) imide", "LiFSI", "LiN (SC> 2 F) 2" are used equivalently, "Bis (sulfonyl) imide lithium", 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 99.5% by weight, advantageously at least 99.95% by weight, and optionally comprising the following impurities in amounts indicated: 0 <H2q <40 ppm, 0 <Cl <80 ppm, 0 <S0 _{April ²} £ 80 ppm, 0 <F <20 ppm, 0 <FSOsLi <20 ppm, 0 <FSC> 2NH 2 ≤5 ppm, 0 <K ⁺ <50 ppm, and 0 <Na ⁺ <80 ppm.

In the context of the invention, the term "ppm" means 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 may be Li-ion batteries of mobile devices (eg mobile phones, cameras, tablets or laptops), or electric vehicles, or renewable energy storage (such as than photovoltaics or wind energy).

In the context of the invention, "between x and y" or "ranging from x to y" means an interval in which the terminals x and y are included. For example, the temperature "between -20 and 80 ° C" includes in particular the values -20 ° C and 80 ° C.

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

The present invention is illustrated by the following example, to which it is however not limited.

EXAMPLES

Methods of

The anion analysis conditions in ion chromatography (Cl) are as follows: o Thermo ICS 5000 DUAL device

o Precolumn: AG19

o AS19 column o Flow rate 1 ml / min

o Isocratic KOH eluent at 20 mmol / l

o Conductivity detection

o 4 mm ASRS suppressor with 50 mA of imposed current

o Injection of 25 μl of LiFSI solutions at 5 g / l and 10 g / l according to the sensitivity required for the present anionic species

o Calibration of each anionic species with five synthetic solutions ranging from 0.1 mg / l up to 25 mg / l.

The detection limits of anions by this method are as follows:

LD (F) = 10 ppm LD (Cl) = 10 ppm LD (SO ₄ ² -) = 20 ppm

The ion analysis conditions for ion chromatography (Cl) are as follows: o Thermo ICS 5000 DUAL device

o Precolumn: CG16

o Column CS16

o Flow rate 1 ml / min

o isocratic methanesulfonic acid eluent at 30 mmol / l

o Conductivity detection

o CSRS 4 mm suppressor with 88mA of imposed current

o Injection of 25 ml of LiFSI solutions at 5 g / l and 10 g / l according to the required sensitivity per cationic species present.

o Calibration of each cationic species with five synthetic solutions ranging from 0.1 mg / l up to 25 mg / l.

The limits of detection of cations by this method are as follows:

LD (K ⁺ ) = 20 ppm LD (Na ⁺ ) = 20 ppm

The NMR analysis conditions of the fluorinated species such as FSO ₃ L1 and FSO ₂ NH ₂ in ¹⁹ F, H1 NMR are the following:

Equipment: The NMR spectra and quantifications were carried out on a Bruker AV 400 spectrometer, at 376.47 MHz for ¹⁹ F, on a 5 mm BBFOL probe.

Sampling:

The samples are dissolved in DMSO-d6 (about 30 mg in 0.6 ml). In the case of fluoride detection or addition of LiF to verify the undesirable presence of fluorides, the solvent used is D2O due to the insolubility of LiF in DMSO.

Quantification: The relative NMR quantification of fluorine 19 ( ¹⁹ F NMR) is done by integrating the signals of the fluorinated species, weighted by the number of fluorines contributing to the signal, a method well known to those skilled in the art.

Absolute quantification by ¹⁹ F NMR is done by the addition of α, α, α-trifluorotoluene (TFT), Aldrich in the tube containing the sample, and by integrating the signals of the fluorinated species to be assayed in comparison with that of the CFs. ₃ of this internal standard, according to a method well known to those skilled in the art. The limit of quantification of a species is of the order of fifty ppm.

Water content :

Produced by assay of Karl Fischer type 684 KF coulometer coupled to 860 KF Thermoprep (Metrohm material).

The solid LiFSI sample is transferred to a glove box in a bottle suitable for Thermoprep. It is heated for 30 minutes at 50 ° C. and then the gas phase is introduced into the assay cell of the KF titrimeter.

Example: Process for manufacturing LiFSI by direct lithiation

In a 2-liter glass reactor thermostatically controlled by a circulation of temperature-controlled thermofluid, provided with stirring, a temperature probe, a refrigerant thermostated at 5 ° C connected to a water trap, introduced 240g of sulfamic acid and 255g of 95% sulfuric acid. At room temperature, 1,187 g of thionyl chloride are poured. With stirring, the reaction mixture is protected up to 35 ° C. in successive stages of + 5 ° C. Gaseous evolution occurs at 35 ° C. The rise in temperature is continued up to 95 ° C. (wall temperature) by controlling the evolution of gas. The total duration of the reaction is 66 hours.

A white product of 608 g corresponding to 1 15% of the expected theoretical weight is recovered. With gentle stirring, 314 g of dioxane are added to the reaction mixture. 461 g of the bis (chlorosulfonyl) imide mixture are transferred with dioxane in a 1 liter autoclave. This autoclave having a PTFE skirt is thermostatically controlled by a thermofluid circulation in a double wall, provided with stirring, a temperature probe, a dip tube and a refrigerant. Under stirring, 123 g of anhydrous HF gas at a flow rate of 15 g / h are introduced by means of the dip tube. The temperature of the medium is maintained between 22 ° C and 25 ° C throughout the reaction. HF and HCl evolution is observed during fluorination. These gases are trapped.

At the end of the reaction, the reaction medium is degassed using a 3.5 l / hr flush with nitrogen for 12 hours. 392 g of solution are obtained. 390 g of solution resulting from the fluorination reaction are taken up. The total acidity of this mixture is measured which is 2 moles, which corresponds to the acidity of the HFSI and HF remaining in the medium after degassing. In a thermostatically stirred reactor equipped with a PTFE pouring funnel connected with a PTFE dip tube and a temperature probe, 148 g of LHCCh are suspended in 400 g of deionized water. The reaction mixture from the fluorination is poured through the dropping funnel by adjusting the feed rate so as to maintain the reaction temperature under 20 ° C. At the end of the reaction, the reaction medium is recovered and filtered. The cake is washed with 125 g of butyl acetate. The filtrate is extracted 3 times with 175 g of butyl acetate and then with 95 g of butyl acetate and then 200 ml of butyl acetate.

The butyl acetate fractions are combined. They are re-extracted with deionized water. The butyl acetate phase is removed. The aqueous phases are combined and then extracted again with butyl acetate (3 extractions). The butyl acetate phases are combined and then concentrated under vacuum at a temperature of 40 ° C. under a pressure of 20mbars on a rotary evaporator. The solids content of the concentrate is 44%. This solution is then concentrated on a "short path" thin film evaporator under 0.5mbar at 60 ° C. The concentrate is rapidly mixed with 100 g of dichloromethane. LiFSI crystallizes. The solid LiFSI was recovered by filtration and dried in vacuo at 40 ° C. 91 g of LiFSI are obtained, the analysis of which is as follows:

LD: detection limit

Claims

1. Process for the preparation of a compound of formula (III) below:

R ₂ - (S0 ₂₎ Li -N (S0 ₂₎ -E (III) 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 ₆ , 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 ₇ OR C ₉ F ₁₉ , preferably R ₂ representing F;

said method comprising:

a step b) comprising:

a step b1) of fluorination of a compound of formula (I) below: R _I - (S0 ₂ ) -NH- (S0 ₂ ) -CI (I) in which 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 ₆ , C ₄ H ₂ F ₇ , C ₄ H ₄ F ₅ , C ₅ F ₁₁ , CeF ₁₃ , C ₇ F ₁₅ , C ₈ F 17 OR C ₉ F _19, R 1 preferably representing Cl;

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

o a possible step b2) of distillation of the composition obtained in step b1);

The process 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. Process according to any one of claims 1 to 2, further comprising a step a), prior to step b), comprising the reaction of a sulfamide of formula (A) below:

RO- (S0 ₂ ) -NH ₂ (A)

in which Ro 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 HSF ₂ , C ₂ F ₅ , C ₃ F ₇ , C3H4F3, C3HF6, C4F9, C4H ₂ F7, C4H4F5, C5F11, C6F13, C7F15, C9F19 or CeF;

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

4. A process according to any one of claims 1 to 3, wherein the lithium salt is selected from the group consisting of LiOH, LiOH, H ₂ O, UHCO 3, Li ₂ CO ₃ , LiCl, and mixtures thereof. the lithium salt being preferably Li ₂ CO ₃ .

The method of any one of claims 1 to 4, wherein:

the composition comprising at least one lithium salt is an aqueous composition, preferably an aqueous suspension or an aqueous solution; or o the composition comprising at least one lithium salt is a solid composition, preferably the composition consists of at least one lithium salt.

The method of any one of claims 1 to 5, wherein:

7. Method according to any one of claims 1 to 6, wherein step c) 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. ° C, and in particular less than or equal to 15 ° C.

8. Process according to any one of claims 1 to 7, further comprising a step d) of purifying the compound of formula (III).

9. Process according to any one of claims 1 to 8, comprising a step b2) of distillation of the composition obtained in step b1).

10. Process according to any one of claims 1 to 9, wherein the step b2) of distillation of the composition obtained in step b) allows to form and recover: a. a first stream F1 comprising HF, the organic solvent SOI, and 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.

The process according to claim 10, wherein the stream F2 is subjected to a distillation step in a second distillation column, to form and recover:

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

12. Process according to any one of claims 1 to 9, wherein the step b2) of the distillation of the composition obtained in step b1) makes it possible to form and recover: a first stream F'1 comprising HF, the organic solvent SOI and optionally HCl, preferably at the top of the distillation column, said flow F'1 being gaseous or liquid;

13. Process according to any one of Claims 1 to 12, in which the distillation step b2) is carried out at a pressure ranging from 0 to 5 bar abs, preferably from 0 to 3 bar abs, and preferentially from 0 to 1 bar abs.

14. Process according to any one of Claims 1 to 13, in which the distillation step b2) is carried out:

15. Process according to any one of claims 1 to 14, further comprising a step b3) comprising dissolving the composition obtained in step b1) or b2), in an organic solvent SO2.

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