Method for producing alkali sulfonylimide salts

Abstract

The present invention relates to a method for producing salts of bis(chlorosulfonyl)imides (HCSI salts) that is economically feasible on an industrial scale and provides a highly pure product. The present invention also provides a method for producing lithium salts of bis(fluorosulfonyl)imides (LiFSI) in which the HCSI salts are used as intermediate compounds.

Description

[Technical Field]

[0001] Cross-reference to related patent applications This application claims priority to European application No. 22306391.8 filed on September 22, 2022, the entire contents of which are incorporated herein by reference for all purposes.

[0002] The present invention relates to a method for producing salts of bis(chlorosulfonyl)imides that is economically feasible on an industrial scale and provides a highly pure product. The present invention also provides a method for producing lithium salts of bis(fluorosulfonyl)imides (LiFSI), in which the HCSI salts are used as intermediate compounds. [Background technology]

[0003] Fluorosulfonylimide salts, especially the lithium salt of bis(fluorosulfonyl)imide (LiFSI), are useful compounds for battery electrolytes. Various processes, reactants, and intermediates leading to LiFSI are described in the patent literature. Canadian Patent No. 2527802 (in the name of Universite de Montreal) describes several routes for preparing LiFSI, including a method for preparing LiFSI in one step starting from bis(chlorosulfonyl)imide (HCSI) using anhydrous hydrogen fluoride (HF). [ka]

[0004] Korean Patent No. 20190001092 (in the name of Lim Kwang Min) also discloses a method for preparing lithium bis(fluorosulfonyl)imide (LiFSI), which includes reacting a lithiating agent, a solvent, bis(chlorosulfonyl)imide (HCSI), and a fluorinating agent.

[0005] Another known process for preparing LiFSI involves a two-step process. For example, one alternative is to fluorinate bis(chlorosulfonyl)imide (HCSI) to bis(fluorosulfonyl)imide (HFSI) using a fluorinating agent such as anhydrous hydrogen fluoride (HF), and then lithiate HFSI to LiFSI using a lithiating agent.

[0006] Another known two-step process for preparing LiFSI uses NHF(HF) as the fluorinating agent. x The method includes a first step of fluorination of bis(chlorosulfonyl)imide (HCSI) to ammonium bis(fluorosulfonyl)imide (NHFSI) using HCl, followed by a second step of lithiation of NHFSI to subsequently yield the LiFSI product.

[0007] Another known two-step process for preparing LiFSI involves the lithiation of HCSI in a first step using a lithiation agent to prepare LiCSI as an intermediate product, followed by the fluorination of LiCSI to LiFSI using a fluorination agent.

[0008] For example, Korean Patent No. 20200049164 (filed by CLS Laboratories Inc.) discloses a method for preparing LiFSI by reacting HCSI with a lithiating agent in a solvent (S1) to produce LiCSI as an intermediate product. In this method, the intermediate product is directly reacted with an anhydrous fluorinating agent without purification / separation. After lithium bis(fluorosulfonyl)imide is obtained, it is filtered and concentrated, and then the solvent is completely removed at low temperature using a thin-film distillation apparatus to obtain a crystalline powder. In this method, the reaction is carried out using a single solvent, and no additional crystallization or recrystallization process is performed.

[0009] Chinese Patent No. 103524387 (in the name of China Nat Offshore Oil Corp.) also discloses a method for preparing LiFSI, including: (I) reacting sulfamic acid and chlorosulfonic acid in thionyl chloride solvent to prepare HCSI; (II) adding LiCl and removing the thionyl chloride solvent to obtain LiCSI; (III) adding acetonitrile or butyl acetate, then adding ZnF, and filtering to obtain a filtrate containing LiFSI salt; and (IV) recrystallizing in methylene chloride to obtain a solid, which is then dried.

[0010] Other methods for the lithiation of HCSI are disclosed, for example, in WO 02 / 053494 (in the name of Hydro-Quebec, Rhodia Chimie). Summary of the Invention

[0011] Applicants have recognized that there remains a need in the art for improved methods for producing intermediate compounds used in the production of LiFSI.

[0012] More specifically, the applicant faced the technical problem of providing a method for producing LiCSI with a low impurity content that can be used to produce LiFSI.

[0013] The applicant was also faced with the problem of providing a process characterized by high productivity using conditions suitable for industrial-scale production. DETAILED DESCRIPTION OF THE INVENTION

[0014] In this application: - Numerical ranges disclosed hereinafter are to be understood as inclusive of the limits unless otherwise specified; - any description, even if made in relation to a particular embodiment, is applicable to and interchangeable with other embodiments of the invention; - Where an element or component is referred to as being included in and / or selected from a list of enumerated elements or components, it is understood that in the relevant embodiments expressly contemplated herein, the element or component may be any one of the individually enumerated elements or components, or may be selected from a group consisting of any two or more of the explicitly enumerated elements or components, and that any element or component enumerated in a list of elements or components may be omitted from such list.

[0015] In a first aspect, the present application provides a method for preparing a salt of bis(chlorosulfonyl)imide [CSI salt] in solid form, comprising: (I) at least one first solvent [solvent (S1)] and a solvent of formula (1): M x B (1) (In the formula, M is selected from lithium, sodium, potassium and ammonium; x is 1 or 2, and B is Cl, CO3 2- , SO4 2- , carboxylates, silicates, preferably metasilicates, borates, preferably tetraborates, and mixtures thereof). to provide a first mixture [Mixture (M1)]; (II) contacting the mixture (M1) with bis(chlorosulfonyl)imide (HCSI) to provide a second mixture (Mixture (M2)) comprising a salt of HCSI selected from lithium-, sodium-, potassium-, or ammonium-CSI (CSI salt) and at least one first solvent (S1); (III) contacting the mixture (M2) with at least one second solvent [solvent (S2)] to provide the CSI salt in solid form. wherein the at least one second solvent (S2) forms a homogeneous mixture with the at least one first solvent (S1) and is a poor solvent for the CSI salt.

[0016] As used herein and in the following claims, the expression "poor solvent for the CSI salt" in relation to at least one second solvent (S2) is intended to mean that the CSI salt exhibits a solubility of less than 2% by weight, preferably less than 1% by weight, in said at least one second solvent (S2).

[0017] The process of the present invention can be carried out continuously or batchwise.

[0018] For example, the method of the present invention can be stopped after step (II) to recover the CSI salt from mixture (M2).

[0019] According to this embodiment, the method of the present invention preferably comprises, after step (II), a step (II-b) of isolating the CSI salt from the mixture (M2).

[0020] Preferably, when M is lithium in formula (1), the compound is selected to not generate water or soluble species during the course of the reaction.

[0021] Advantageously, when M in formula (1) is lithium, said compound may be lithium chloride (LiCl), lithium carbonate (Li2CO3), lithium sulfate (Li2SO4), lithium carboxylate (Li n (RCO2) n ), Li2SiO3, Li2B4O7 and mixtures thereof.

[0022] Preferably, in formula (1), M is sodium. The compound is preferably selected from the group comprising sodium chloride (NaCl), sodium carbonate (Na2CO3), sodium sulfate (Na2SO4) and mixtures thereof.

[0023] Preferably, in formula (1), M is ammonium. The compound is preferably selected from the group comprising ammonium chloride (NH4Cl), ammonium carbonate, and mixtures thereof.

[0024] Preferably, the molar ratio of HCSI to the compound of formula (1) when M is lithium is in the range of 1:100 to 20:1, in particular 1:10 to 10:1, more particularly 1:2 to 5:1, and even more particularly 1:1 to 1:1.5.

[0025] When lithium carbonate is used as the compound of formula (1), it is advantageous that the molar ratio of HCSI to Li2CO3 is less than 1, i.e., Li2CO3 is in excess. A molar ratio of 1:2 to 1:5 is more preferred.

[0026] More preferably, the compound of formula (1) is anhydrous lithium chloride (LiCl) in solid form.

[0027] When LiCl is used as the compound of formula (1), the molar ratio of HCSI to LiCl is advantageously 1:1 to 1:1.5.

[0028] Preferably, said solvent (S1) is selected from the group comprising carbonates such as dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), ethylene carbonate (EC), propylene carbonate (PC), esters such as ethyl acetate, n-butyl acetate, ethers such as tetrahydrofuran (THF), methyl tert-butyl ether (MTBE), methyl tetrahydrofuran (Me-THF), etc. Carbonates are particularly preferred.

[0029] In both cases, the solvent (S1) is different from thionyl chloride (SO2Cl).

[0030] The HCSI provided in step (II) of the method of the present invention can be prepared by known methods, for example by - reacting chlorosulfonyl isocyanate (ClSO2NCO) with chlorosulfonic acid (ClSO2OH); - Reacting cyanogen chloride (CNCl) with sulfur trioxide (SO3) and chlorosulfonic acid (ClSO2OH), or - Reacting sulfamic acid (NH2SO2OH) with thionyl chloride (SOCl2) and chlorosulfonic acid (ClSO2OH) It can be produced by

[0031] In one embodiment, HCSI is produced by reacting chlorosulfonic acid (ClSOOH) with chlorosulfonyl isocyanate (ClSONCO). According to this embodiment, step (i) comprises preparing a reaction mixture comprising crude HCSI, a heavy fraction, and a light fraction in a reactor by reacting chlorosulfonyl isocyanate (ClSONCO) with chlorosulfonic acid (ClSOOH).

[0032] In another embodiment, HCSI is produced by reacting sulfamic acid (NHSOOH), chlorosulfonic acid (ClSOOH), and thionyl chloride (SOCl). The sulfamic acid utilized can be ground to a certain particle size and vacuum dried to reduce its water content and increase the reaction rate of the conversion, thereby significantly shortening the reaction time. When HCSI is prepared by the so-called sulfamine route, the sulfamic acid used can optionally be ground and vacuum dried to reduce its water content and increase the reaction rate of the conversion, thereby significantly shortening the reaction time.

[0033] In another embodiment, HCSI is produced by reacting cyanogen chloride CNCl with sulfuric anhydride (SO3) and chlorosulfonic acid (ClSO2OH).

[0034] The HCSI may be provided as a composition containing the HCSI mixed with at least one other compound. Such at least one other compound may be an undesirable compound. The undesirable compound may be selected from, for example, ions, solvents, water, and / or reaction by-products. For example, the HCSI may be provided as a composition containing 80 to 99 wt. %, preferably 85 to 98 wt. %, and more preferably 90 to 97 wt. % HCSI, with the remaining 100 wt. % being one or more other compounds. Such other compounds are removed by the method of the present invention.

[0035] Advantageously, the HCSI is provided in step (II) in its molten form.

[0036] According to this embodiment, prior to step (II), the HCSI is heated to a temperature below its melting point (Tm HCSI ) is heated to a temperature above

[0037] Although the melting point of the HCSI is affected by the presence and amount of impurities, it is preferred that the HCSI be heated to a temperature of 30° C. or higher, such as 37° C. or higher, for example 38° C. or higher, 40° C. or higher, 45° C. or higher, or even 50° C. In any case, heating is carried out at a temperature below the decomposition temperature of the HCSI.

[0038] Preferably, step (II) is carried out at a temperature of 15 to 60°C, more preferably 20 to 35°C.

[0039] Preferably, step (II) is carried out at atmospheric pressure.

[0040] Preferably, said at least one second solvent (S2) is selected from the group comprising dioxane, chlorinated solvents such as dichloromethane (DCM), alkanes, toluene, xylene, with dioxane being particularly preferred.

[0041] Preferably, step (III) is carried out at a temperature of 15 to 60°C, more preferably 20 to 35°C.

[0042] Preferably, step (III) is carried out at atmospheric pressure.

[0043] Preferably, the solid form of the CSI salt obtained at the end of step (III) is in the form of a solvate with said at least one second solvent (S2).

[0044] Preferably, the process according to the invention comprises, after step (III), at least one step (IV) of separating the CSI salt from impurities.

[0045] This separation step can be carried out by any separation means known to those skilled in the art, for example, separation can be carried out by filtration, more preferably filtration under pressure and / or under vacuum, or decantation.

[0046] The mesh size of the filtration medium is preferably 100 μm or less, 50 μm or less, 10 μm or less, 2 μm or less, 0.45 μm or less, or 0.22 μm or less.

[0047] The isolated product may be washed one or more times with a suitable solvent.

[0048] The separation step can be performed once or can be repeated two or more times.

[0049] Some or all of the steps of the process according to the invention are advantageously carried out in equipment that can withstand the corrosion of the reaction medium.

[0050] For this purpose, corrosion-resistant materials are selected for the parts that come into contact with the reaction medium, such as alloys based on molybdenum, chromium, cobalt, iron, copper, manganese, titanium, zirconium, aluminum, carbon, and tungsten sold under the Hastelloy® brand, or alloys of nickel, chromium, iron, and manganese with copper and / or molybdenum added thereto sold under the names Inconel® or Monel™, more particularly Hastelloy C276 or Inconel 600, 625, or 718 alloys. Austenitic steels, more particularly stainless steels such as 304, 304L, 316, or 316L stainless steels, may also be selected. Steels with a nickel content of at most 22% by weight, preferably between 6% and 20% by weight, and more preferentially between 8% and 14% by weight, are used. 304 and 304L steels have nickel contents ranging from 8% to 12% by weight, while 316 and 316L steels have nickel contents ranging from 10% to 14% by weight. More particularly, 316L steel is selected. Equipment made of or coated with polymeric compounds resistant to corrosion by the reaction medium can also be used. Materials such as PTFE (polytetrafluoroethylene, or Teflon) or PFA (perfluoroalkyl resin) can be mentioned in particular. Glass equipment, such as glass-coated alloys, can also be used. The use of equivalent materials would not be outside the scope of the present invention. Other materials suitable for contact with the reaction medium include graphite derivatives. The material for filtration must be compatible with the medium used. Fluorinated polymers (PTFE, PFA), loaded fluorinated polymers (Viton™), as well as polyester (PET), polyurethane, polypropylene, polyethylene, cotton, and other compatible materials can be used.

[0051] All raw materials used in the process according to the invention, such as reactants, may preferably exhibit very high purity standards: preferably, their content of metal components such as Na, K, Ca, Mg, Fe, Cu, Cr, Ni, Zn is less than 10 ppm, more preferably less than 5 ppm or less than 2 ppm.

[0052] According to the method of the present invention, a pure or substantially pure salt of LiCSI is obtained as a solid, which means that the LiCSI salt can be used directly in other reactions, in particular in the preparation of LiFSI.

[0053] In another aspect, the present invention relates to a solid solvated complex [CSI solvate] comprising a solid lithium, sodium, potassium, or ammonium salt of bis(chlorosulfonyl)imide and dioxane as the solvating solvent.

[0054] The term "solvate" as used herein and in the claims that follow is intended to denote a solid lithium, sodium, potassium or ammonium salt of bis(chlorosulfonyl)imide (also called CSI salt) that contains molecules of said solvent (S2) bound to it through non-covalent bonds.

[0055] Preferably, the weight ratio of CSI salt to solvent (S2) in the CSI solvate ranges from 1:1 to 1:4, as measured on a dry powder.

[0056] Advantageously, the solvent (S2) in the CSI solvate is dioxane.

[0057] Advantageously, said CSI solvate is obtained at the end of step (III) or step (IV) of the process according to the invention.

[0058] Preferably, the CSI solvate is in a crystalline form.

[0059] In a further embodiment, the present invention relates to the use of the CSI solvate obtained at the end of step (II) or step (IV) as defined above for the preparation of a bis(fluorosulfonylimide) salt [FSI salt].

[0060] Preferably, the FSI salt is selected from the lithium, ammonium and sodium salts.

[0061] A further object of the present invention is a method for preparing a salt of a bis(fluorosulfonyl)imide [FSI salt], comprising the steps of: (V) contacting the CSI salt or CSI solvate defined above with at least one fluorinating agent to obtain an FSI salt. The present invention relates to a method comprising:

[0062] The fluorinating agent used in the method of the present invention is not limited.Preferably, it is anhydrous hydrogen fluoride (aHF).Such aHF advantageously has a high purity, for example, greater than 99.95 mol%, and contains less than 1000 ppm of HO, less than 10 ppm of SO, less than 100 ppm of HSO, less than 20 ppm of HSiF, and less than 25 ppm of As.

[0063] When HF is used as a fluorinating agent in step (V), it can be introduced into the reaction mixture in any form. It can be introduced as a liquid or as a gas into the reaction vessel. For example, step (V) can be carried out by fluorinating LiCSI using HF gas in a fluidized bed.

[0064] According to another embodiment, the fluorinating agent is (i) KF(HF) p (wherein p is 0 or 1), (ii) NaF(HF) p (wherein p is 0 or 1), (iii) X2F(HF) p (wherein X2 is an onium cation and p is 0 or 1), (iv) NHF(HF) p (wherein p varies from 0 to 10), (v) LiF, (vi) ZnF2 and preferably selected from the group consisting of:

[0065] According to a preferred embodiment, specific examples of the fluorinating agent (iv) include NH4F, NH4F·HF, NH4F·2HF, NH4F·3HF and NH4F·4HF.

[0066] A preferred fluorinating agent (iv) is NH4F.

[0067] In the present invention, the fluorinating agent used in step (V) is preferably anhydrous. The water content can be preferably less than 100 ppm, less than 50 ppm, or even less than 10 ppm. Those skilled in the art can determine the most suitable method for measuring such water content. For example, such methods can include infrared techniques or Karl Fischer titration, if applicable.

[0068] In some embodiments, the stoichiometric amount (also called molar amount) of fluorinating agent to solid form of CSI salt is 0.1:1 to 50:1, for example, 1:1 to 10:1 or 2:1 to 8:1.

[0069] In some embodiments, the stoichiometric amount of fluorinating agent is 2 or more equivalents per mole of CSI salt, preferably LiCSI, for example, 2 to 100 equivalents per mole of CSI salt, preferably LiCSI. Preferably, the stoichiometric amount of fluorinating agent is 2 to 80 equivalents per mole of CSI salt, preferably LiCSI, or 2 to 60 equivalents per mole of CSI salt, preferably LiCSI. More preferably, the stoichiometric amount of fluorinating agent is 2 to 50 equivalents per mole of CSI salt, preferably LiCSI.

[0070] Preferably, step (V) is carried out in the presence of a solvent.

[0071] Advantageously, when the solid form of the CSI salt is a solvate with dioxane, said solvent is preferably dioxane.

[0072] Preferably, step (V) is carried out at a temperature of 25 to 90°C, more preferably 40 to 90°C.

[0073] Preferably, step (V) is carried out at a pressure of 1 to 2 bar.

[0074] Residual HF present in the final reaction crude product can be eliminated using any relevant method such as evaporation under vacuum or stripping with an inert gas or a combination thereof.

[0075] The LiFSI obtained by the method of the invention advantageously exhibits at least one, and more preferably all, of the following: - 19 a purity of at least 98% by weight, e.g., 99% to 100% by weight or 99.50 to 100% by weight, as measured by F NMR; a solvent content measured by GC of less than 20%, less than 10%, less than 1%, preferably between 0% and 1% by weight, - Water content less than 500 ppm, less than 100 ppm, less than 50 ppm, or even less than 20 ppm as measured by infrared method.

[0076] The LiFSI of the present invention advantageously exhibits at least one, and more preferably all, of the following: - less than 100 ppm, preferably less than 50 ppm, more preferably less than 10 ppm or more preferably less than 2 ppm chloride (Cl - ) content, - less than 100 ppm, preferably less than 50 ppm, more preferably less than 40 ppm, more preferably less than 30 ppm, more preferably less than 20 ppm fluoride (F - ) content, and less than 100 ppm, preferably less than 50 ppm, more preferably less than 10 ppm or more preferably less than 2 ppm sulfate (SO 2- ) content.

[0077] The fluoride and chloride content can be measured by argentometric titration using an ion selective electrode (or ISE). The sulfate content can be measured by ion chromatography of the following characteristics, preferably all of the following characteristics: - Chromatographic or turbidimetric purity.

[0078] Advantageously, lithium bis(fluorosulfonyl)imide (LiFSI) prepared according to the method of the present invention can be used in electrolyte compositions for electrochemical cells.

[0079] In a further aspect, the present invention relates to an electrolyte composition comprising LiFSI obtained by the process of the present invention. Advantageously, said electrolyte composition is a non-aqueous electrolyte composition.

[0080] To the extent that the disclosure of any patents, patent applications, and publications incorporated herein by reference conflicts with the statements of this application to the extent that a term may be unclear, the statements of this application shall control.

[0081] The present invention is illustrated by the following examples, which are intended to illustrate but not limit the invention. [Example]

[0082] material The following were purchased from Merck: anhydrous lithium chloride (99% - #793620); carbon tetrachloride (CCl4->99.9% - #270652); dimethyl carbonate < diethyl carbonate (DEC-99% - #D91551).

[0083] The following were purchased from VWR: dichloromethane (DCM-#25631.293); dioxane (VWR#23532.297->99%).

[0084] HCSI was prepared in-house starting from chlorosulfonyl isocyanate and chlorosulfonic acid and then used in the molten state.

[0085] method All solvents (DCM, CCl4, DEC, DMC, dioxane) used in the following examples were dried using molecular sieves before use.

[0086] Comparative Example A1 - Preparation of LiCSI solution by lithiation of HCSI using CCl4 as solvent A double-jacketed 100 mL glass reactor equipped with an integral baffle, a mechanical stirrer, a condenser, and connected to a 15 wt % aqueous KOH scrubber was flushed with argon for 30 minutes. The reactor was charged with 3.18 g of anhydrous lithium chloride and 24.7 g of carbon tetrachloride.

[0087] In a glove box, a dropping funnel was charged with 26 g of CCl4 and 20.0 g of molten HCSI, and the funnel was connected to the reactor.

[0088] After fixing the condenser temperature setpoint at 6°C and the stirring speed at 700 rpm, the HCSI solution was introduced over 20 minutes. The reaction medium was heated to reflux. After 5 hours of reflux, the conversion of LiCl was about 19% (estimated by KCl titration in the scrubber).

[0089] To compensate for solvent loss, reflux was extended for 60 h with replenishment of CCl4. The slurry was filtered, washed with 20 mL of CCl4, and dried under argon to give a slightly brown powder (8.3 g).

[0090] Proton NMR of the filtrate diluted with CDCl3 indicates the presence of HCSI, and titration of chloride in the solid suggests 6 wt% LiCl remaining in the LiCSI.

[0091] Overall, the reaction rate was considered too slow.

[0092] Example A2 - Preparation of LiCSI solution by lithiation of HCSI using DEC as solvent A double-jacketed 250 mL glass reactor equipped with an integral baffle, mechanical stirrer, condenser, bottom valve, and connected to a 15 wt % aqueous KOH scrubber was flushed with nitrogen for 60 minutes. The reactor was charged with 6.34 g of anhydrous lithium chloride and 15.98 g of diethyl carbonate (DEC).

[0093] In a glove box, a glass flask was charged with 31.77 g of molten HCSI and 15.98 g of DEC. The resulting slightly yellow solution was transferred to a syringe and attached to a syringe pump.

[0094] After fixing the condenser temperature set point at 10° C., the reaction mixture at 25° C. and the stirring speed at 400 rpm, 47.84 g of HCSI solution was introduced over 27 minutes.

[0095] The stirring and temperature were maintained for 7.6 hours, resulting in a beige slurry that settled easily.

[0096] The conversion rate of HCSI estimated from the generation of HCl was 97.0%.

[0097] When the supernatant was analyzed by NMR, no HCSI was detected by proton NMR. 7 In Li NMR, a LiCSI signal was confirmed at 1.08 ppm.

[0098] The crude reaction product was diluted with 18.99 g of DEC and drawn off onto a filter under a controlled N2 atmosphere. The solid residue containing excess LiCl was washed with 2.00 g of DEC, and 79.25 g of filtrate containing 36 wt % LiCSI was recovered.

[0099] Overall, very high selectivities were achieved, with complete conversion requiring only a few hours using mild conditions.

[0100] Example A3 - Preparation of LiCSI solution by lithiation of HCSI using DEC as solvent A double-jacketed 500 mL glass reactor equipped with an integral baffle, mechanical stirrer, condenser, bottom valve, and connected to a 15 wt % aqueous KOH scrubber was flushed with nitrogen for 60 minutes. The reactor was charged with 56.5 g of anhydrous lithium chloride and 94.3 g of DEC.

[0101] In a glove box, a dropping funnel was charged with 192.9 g of molten HCSI (prepared from chlorosulfonyl isocyanate and chlorosulfonic acid) and 100.8 g of DEC, and then the funnel was connected to the reactor.

[0102] After fixing the condenser temperature set point at 13° C., the reaction mixture at 30° C., and the stirring speed at 400 rpm, the HCSI solution was introduced over 45 minutes. The stirring and temperature were maintained for 4.5 hours.

[0103] The conversion rate of HCSI estimated from the generation of HCl was 98.6%.

[0104] The reaction crude was withdrawn and filtered in the glove box, and 354 g of clear filtrate was separated together with 18 g of solid residue.

[0105] The filtrate was analyzed by NMR, and no HCSI was detected by proton NMR. 7 In Li-NMR, a signal of LiCSI was observed at 1.14 ppm.

[0106] Comparative Example B1 - Preparation of solid LiCSI using DCM as antisolvent 32.9 g of LiCSI solution obtained as described in Example A2 above was concentrated to 20.0 g using a rotary evaporator at 50° C. and 8 mbar under nitrogen atmosphere.

[0107] To the concentrated LiCSI was added 36.5 g of dichloromethane (DCM) at room temperature, and the mixture was stored at −26° C. for 16 hours. A white solid formed, and the suspension was filtered through a 0.22 micron PTFE membrane in a glove box.

[0108] A solid cake was observed which was washed three times with 10 g of DCM and dried to give a pale white powder.

[0109] The powder was analyzed by NMR ( 1 H, 7The product was analyzed by FTIR and LiCSI. LiCSI was observed, but the recovery was poor, i.e., 14% (1.8 g).

[0110] Comparative Example B2 - Crystallization of LiCSI from DEC Solution 20.35 g of LiCSI solution obtained as described in Example A2 above was placed in a 25 mL three-neck glass round-bottom flask equipped with a PTFE stir bar inside a glove box under an argon atmosphere.

[0111] The flask was connected to a vacuum pump and placed in a thermostatic bath, and then DEC was distilled off at 8 mbar, 35° C., and 600 rpm. After 2 hours, DEC no longer evaporated and the LiCSI concentration reached 54 wt %.

[0112] The concentrated solution was seeded with 13 mg of solid LiCSI and stored at −26° C. After 7 days, no significant LiCSI crystallization was observed.

[0113] Example B3 - Preparation of solid LiCSI using dioxane as antisolvent 36.1 g of LiCSI solution obtained as described in Example A3 above was mixed with 100 g of dioxane in a glove box. The solution was seeded with 53 mg of solid LiCSI obtained according to the procedure described in Example A3 and stored at −26° C. for 3 days. Upon returning to room temperature, the sample was a white suspension, which was filtered through a 0.22 micron PTFE membrane and washed with dioxane.

[0114] The cake was dried under vacuum at 50°C to give a dry white powder (25.87g), which still contained 47% by weight of dioxane ( 1 1 H NMR and DSC analysis).

[0115] The LiCSI recovery rate was 75%.

[0116] Example C1 - Preparation of LiFSI using aHF starting from LiCSI·dioxane solvate in dioxane Solid LiCSI·dioxane (23 g, dioxane content 47 wt.%) prepared according to the procedure in Example B3 was introduced into a thoroughly inertized C276 autoclave equipped with a magnetic stirrer, a heating / cooling double jacket, a temperature probe, a pressure sensor, a condenser, and connected to a basic aqueous scrubber under a blanket of N2.

[0117] Subsequently, dioxane (91.4 g) was added via cannula. After homogenization for 15 minutes by stirring at 800 rpm, anhydrous HF (66 g) was slowly added. After complete addition of HF, the resulting mixture was heated at 70° C. for 22 hours. The pressure reached a maximum of 1.6 bar.

[0118] After releasing the pressure, the reaction mixture was stripped with N2 at 50°C for 12 hours to evacuate most of the excess HF.

[0119] Quantitative determination of the reaction mixture 19 F NMR showed that LiFSI was the major species with a selectivity of over 72%. Chloride titration of the scrubber showed a high conversion of about 96%.

[0120] Comparative Example C2 - Preparation of LiFSI with aHF, starting from a solution of LiCSI in DEC A solution of 50.4 wt.% LiCSI in DEC (111.6 g) was cannulated under a N blanket into the vessel described in Example C1. After homogenization by stirring at 800 rpm for 15 minutes, anhydrous HF (8.5 g) was slowly added. The mixture was heated at 70°C for 43 hours. Most of the excess HF was evacuated by stripping the reaction mixture with N at 50°C for 12 hours. Fluoride / chloride titration of the scrubber indicated low conversion (25.1% chloride recovery in the scrubber).

[0121] Quantitative determination of the reaction mixture 19F-NMR indicated a mixture of LiFSI (7.2%) with significant amounts of FSO3Li, FSO2NH2 (or their lithium salts), residual HF, and other unknown impurities.

[0122] Comparative Example C3 - Preparation of LiFSI with NHF, starting from a solution of LiCSI in DEC A 50 mL glass round-bottom flask equipped with a condenser, a magnetic stirrer, and a thermostated oil bath was flushed with nitrogen for 30 minutes. The reaction vessel was charged with 15.55 g of diethyl carbonate and 7.74 g of NHF.

[0123] In a glove box, 48 g of LiCSI solution (37 wt. % LiCSI) obtained by lithiation of HCSI in DEC was loaded into a 60 mL PP syringe and attached to a syringe pump. The condenser temperature was set to 10 °C, the reaction mixture was set to 60 °C, and the stirring speed was fixed at 400 rpm. 46.34 g of LiCSI solution was then introduced over 60 min. The medium temperature was then set to 75-80 °C for 10 h. After cooling to room temperature, the supernatant was sampled. The total chloride content was approximately 60% of the initial value (titration with aqueous solution), indicating that the LiCSI was not completely converted. 19 F-NMR showed that 53.0 ppm of FSI anion was formed along with by-products (FSI yield = 30%).

[0124] Heating was extended at 75-85°C for 5 hours, after which the supernatant was sampled again. The chloride content had dropped to 50 ppm. 19 The FSI yield was 53% by F-NMR analysis. 7 No lithium signal was detected in the liquid phase by Li-NMR.

Claims

1. 1. A method for producing a salt of bis(chlorosulfonyl)imide [CSI salt] in solid form, comprising the steps of: (I) at least one first solvent [solvent (S1)] and a solvent represented by formula (1): (1)M ｘ B (In the formula, M is selected from lithium, sodium, potassium and ammonium; x is 1 or 2, and B is Cl, CO ３ ２－ , S.O. ４ ２－ , carboxylates, silicates, preferably metasilicates, borates, preferably tetraborates, and mixtures thereof. to provide a first mixture [Mixture (M1)]; (II) contacting the mixture (M1) with bis(chlorosulfonyl)imide (HCSI) to provide a second mixture (M2) comprising a salt of HCSI selected from lithium-, sodium-, potassium-, or ammonium-CSI (CSI salt) and at least one first solvent (S1); (III) contacting the mixture (M2) with at least one second solvent [solvent (S2)] to provide the CSI salt in solid form. wherein said at least one second solvent (S2) forms a homogeneous mixture with said at least one first solvent (S1) and is a poor solvent for said CSI salt.

2. In the compound of formula (1), M is lithium, and the compound of formula (1) is LiCl, Li ２ CO ３ , Li ２ SO ４ , Li ｎ (R.C.O. ２ ) ｎ , Li ２ SiO ３ , Li ２ B ４ O ７ and mixtures thereof; or M is sodium, and the compound of formula (1) is NaCl, Na ２ CO ３ , Na ２ SO ４ and mixtures thereof, or M is ammonium, and the compound of formula (1) is NH ４ 2. The method of claim 1, wherein the ammonium carbonate is selected from the group consisting of ammonium chloride, ammonium carbonate, ammonium nitrate ...

3. 3. The process according to claim 1 or 2, wherein the solvent (S1) is selected from the group comprising carbonates such as dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), ethylene carbonate (EC), propylene carbonate (PC), esters such as ethyl acetate, n-butyl acetate, ethers such as tetrahydrofuran (THF), methyl tert-butyl ether (MTBE), methyl tetrahydrofuran (Me-THF).

4. The solvent (S1) is thionyl chloride (SO ２ The method according to any one of claims 1 to 3, wherein the hydroxyl group is different from hydroxyl group (C1).

5. The method according to any one of claims 1 to 4, wherein the HCSI is provided in step (II) in its molten form.

6. Before step (II), HCSI is dissolved in water at its melting point (Tm ＨＣＳＩ 6. The method of claim 5, comprising the step of heating at a temperature above 100° C., preferably at a temperature of 30° C. or higher.

7. The process according to any one of claims 1 to 6, wherein step (II) is carried out at a temperature of from 15 to 60°C and / or at atmospheric pressure.

8. 8. The method according to any one of claims 1 to 7, wherein said at least one second solvent (S2) is selected in the group comprising dioxane, chlorinated solvents such as dichloromethane (DCM), alkanes, toluene, xylene.

9. 9. The process according to any one of claims 1 to 8, wherein step (III) is carried out at a temperature of from 15 to 60°C and / or at atmospheric pressure.

10. 10. The method according to claim 1, wherein the CSI salt in solid form obtained at the end of step (III) is in the form of a solvate with the at least one second solvent (S2).

11. A solid solvated complex [CSI solvate] comprising a solid lithium salt, sodium salt, potassium salt or ammonium salt of bis(chlorosulfonyl)imide [CSI salt] and dioxane as a solvating solvent.

12. 12. The CSI solvate of claim 11, wherein the weight ratio of CSI salt to dioxane in the CSI solvate is in the range of 1:1 to 1:4, as measured on a dry powder basis.

13. 1. A method for producing a salt of bis(fluorosulfonyl)imide [FSI salt], comprising the steps of: (V) contacting the CSI salt obtained according to any one of claims 1 to 10 or the CSI solvate according to claim 11 or 12 with at least one fluorinating agent to obtain the FSI salt. A method comprising:

14. The fluorinating agent may be prepared from anhydrous hydrogen fluoride, or (i) KF(HF) ｐ (wherein p is 0 or 1); (ii) NaF(HF) ｐ (wherein p is 0 or 1); (iii) X ２ F (HF) ｐ (In the formula, X ２ is an onium cation, and p is 0 or 1), (iv) NH ４ F (HF) ｐ where p varies from 0 to 10. (v) LiF, (vi)ZnF ２ 14. The method of claim 13, wherein the hydroxyl group is selected from the group comprising:

15. 15. An electrolyte composition comprising the FSI salt obtained at the end of the method according to claim 13 or 14.

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