Solvent-free method for preparing salts of bis(fluorosulfonyl)imides

Abstract

The present disclosure relates to a process for preparing salts of bis(fluorosulfonyl)imides and alkali metal salts of bis(fluorosulfonyl)imides from said bis(fluorosulfonyl)imide salts. More specifically, the present invention provides a novel process for producing these salts of bis(fluorosulfonyl)imides that is operable on an industrial scale and for providing high purity bis(fluorosulfonyl)imide salts.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED PATENT APPLICATIONS This application claims priority to European application No. 21306270.6 filed on September 15, 2021, the entire contents of which are incorporated herein by reference for all purposes.

[0002] The present invention relates to a process for preparing salts of bis(fluorosulfonyl)imides and alkali metal salts of bis(fluorosulfonyl)imides from said bis(fluorosulfonyl)imide salts. More specifically, the present invention provides a novel process for producing these salts of bis(fluorosulfonyl)imides which is operable on an industrial scale and for providing high purity bis(fluorosulfonyl)imide salts. [Background technology]

[0003] Bis(fluorosulfonyl)imides and their salts, particularly the lithium salt of bis(fluorosulfonyl)imide (LiFSI), are useful compounds in a variety of technical fields.

[0004] The preparation of bis(fluorosulfonyl)imides and their salts has been described in the literature. Among the various techniques described, the majority use a fluorination reaction with a fluorinating agent in a solvent.

[0005] In particular, WO 2017 / 090877 A1 (CLS) describes a method for producing lithium bis(fluorosulfonyl)imide, which includes the steps of (1) reacting bis(chlorosulfonyl)imide with a fluorinating agent in a solvent, followed by treatment with an alkaline agent, thereby producing ammonium bis(fluorosulfonyl)imide, and (2) reacting ammonium bis(fluorosulfonyl)imide with a lithium base. The solvent used in step (1) is selected from the group consisting of alkyl ketones such as acetone, methyl ethyl ketone, and methyl isopropyl ketone; alcohols such as methanol, absolute ethanol, 1-propanol, and isopropanol; alkyl nitriles such as acetonitrile and propionitrile; and ethers such as tetrahydrofuran and dialkoxyalkanes. The solvent is then removed by distillation and concentration under reduced pressure.

[0006] WO 2012 / 117961A1 (Nippon Soda Co., Ltd.) describes a method for preparing fluorosulfonylimide salts. According to Examples 1 and 2, ammonium di(fluorosulfonyl)imide is prepared from di(chlorosulfonyl)imide in acetonitrile. The solvent is then removed by vacuum distillation.

[0007] JP 2016-145147 A (Nippon Shokubai Co., Ltd.) relates to a method for obtaining a fluorosulfonylimide compound represented by formula (1) by reacting a compound represented by formula (2) with a compound represented by composition formula (3) in a stoichiometric amount of 1 to 3 equivalents per mole of the compound in the presence of a solvent in an amount of 0 to 4 times the mass of the compound. [ka] (In the formula, R 1 is C 1~6 R is a fluoroalkyl group. 6 is halogen or C 1~6 Fluoroalkyl group, Cat1 + and Cat2 +is a monovalent group, and p is an integer from 1 to 10.

[0008] JP 2014-201453 A (Nippon Shokubai Co., Ltd.) describes a method for producing an alkali metal salt of a fluorosulfonylimide, comprising the steps of synthesizing an alkali metal salt of a fluorosulfonylimide in the presence of a reaction solvent containing at least one solvent selected from the group consisting of carbonate-based solvents, aliphatic ether-based solvents, ester-based solvents, amide-based solvents, nitro-based solvents, sulfur-based solvents, and nitrile-based solvents, and then concentrating the alkali metal salt solution of a fluorosulfonylimide by distilling off the reaction solvent in the presence of the reaction solvent and at least one poor solvent for the alkali metal salt of a fluorosulfonylimide selected from the group consisting of aromatic hydrocarbon-based solvents, aliphatic hydrocarbon-based solvents, and aromatic ether-based solvents, and the concentration step comprises the step of mixing the poor solvent with a reaction solution containing the reaction solvent and the alkali metal salt of a fluorosulfonylimide.

[0009] As described in the literature, the preparation of bis(fluorosulfonyl)imides and their salts by fluorination is carried out in a solvent, e.g., an organic solvent, to disperse the reactive substances and keep them reacting. However, such solvents need to be removed after the reaction in order to obtain a product of the highest possible purity that can be used for battery applications. The step to remove the solvent increases the complexity of the industrial process as well as its overall cost. In addition, before being carried out in such a process, the solvent must typically be treated to remove residual amounts of water, since only anhydrous solvents, with residual amounts of water in ppm amounts, are actually used.

[0010] WO 2012 / 096371 A1 (Sumitomo Electric Industries) relates to a method for producing KN(SO2F)2 by dropping HN(SO2Cl)2 (in liquid form) to KF (in powder form) under solvent-free dry conditions to form an intermediate product, which is then allowed to react with KF in an aqueous solvent. More precisely, according to the method described in this document, in a first step, one chlorine element of HN(SO2Cl)2 is replaced by fluorine, resulting in an intermediate product which is the alkali metal salt KN(SO2Cl)(SO2F), and in a second step, the other chlorine element is replaced by fluorine, resulting in the alkali metal salt KN(SO2F)2. According to such a two-step process, HN(SO2Cl)2 is converted into the alkali metal salt KN(SO2Cl)(SO2F), so that, as a result, water can be used in the second step, since water dissolves the alkali metal fluoride.

[0011] According to this document, the first part of the reaction is carried out under solvent-free dry conditions by dropping the reactant in liquid form onto the second reactant in powder form. This results in a paste-like intermediate product that is very difficult to handle industrially. Furthermore, the total conversion of HN(SO2Cl)2 to KN(SO2F)2 is carried out in two steps with separate intermediate products, which adversely affects the yield of the reaction as well as the level of impurities in the final product.

[0012] European Patent No. 2674395 (Nippon Soda Co., Ltd.) discloses that a compound [I] such as ammonium N-(chlorosulfonyl)-N-(fluorosulfonyl)imide is reacted with hydrogen fluoride to obtain a compound [II] such as ammonium N,N-di(fluorosulfonyl)imide.

[0013] European Patent No. 3489193 (Nippon Shokubai Co., Ltd.) discloses a compound of the following formula (1), its preparation method, and its use in electrolyte compositions: [ka]

[0014] WO 2015 / 143866 (Shenzhen Capchem Technology Co., Ltd.) discloses a method for preparing bisfluorosulfonylimides, which includes reacting bischlorosulfonylimides with liquid hydrogen fluoride by adding bischlorosulfonylimides dropwise to an excess of hydrogen fluoride at a temperature below 20° C. Summary of the Invention

[0015] The object of the present invention is to provide a bis(fluorosulfonyl)imide salt X1N(SO2F)2 (X1 is K) that can be carried out on an industrial scale and has high purity. + , Na + or onium cations (e.g. NH4 + The object of the present invention is to provide a method for preparing the compound (C).

[0016] It is an object of the present invention to provide a simpler process for the preparation of salts of bis(fluorosulfonyl)imides which does not require distillation of the reaction solvent.

[0017] In particular, the process of the invention is carried out in the presence of a molten reactant, such as molten NHN(SOCl), or in the presence of a molten reaction product, such as molten KN(SOF) or molten NHN(SOF), which acts to disperse the reactants, and in the absence of a solvent (or in the presence of a very limited amount of solvent).

[0018] The present invention relates to a compound of formula (I): [F-(SO2)-N - -(SO2)-F] n X1 n+ (I) (In the formula, - X1 n+ is K + , Na + and an onium cation, - n is 1 and represents the valence of the cation A process for preparing a salt of a bis(fluorosulfonyl)imide of the formula: Formula (II): [Cl-(SO2)-N - -(SO2)-Cl] n X1 n+ (II) with anhydrous hydrogen fluoride (III), The process is carried out in the absence of a solvent or in the presence of a solvent in an amount of less than 5% by weight, based on the total weight of the reaction mixture, in a molten salt of a bis(fluorosulfonyl)imide of formula (I) and / or a molten salt of a bis(chlorosulfonyl)imide of formula (II).

[0019] The present invention also relates to a compound of formula (I): [F-(SO2)-N - -(SO2)-F] n X1 n+ (I) (In the formula, - X1 n+ is K + , Na + and an onium cation, - n is 1 and represents the valence of the cation The present invention also relates to a salt of a bis(fluorosulfonyl)imide of Such salts can be obtained by the process of the invention, which is characterised in that its amount of solvent is less than 100 ppm, for example less than 50 ppm.

[0020] The present invention also relates to a compound represented by formula (V) F-(SO2)-NX3-(SO2)-F (IV) (wherein X3 represents Li or Cs, preferably Li). A process for preparing a salt of a bis(fluorosulfonyl)imide of the formula: (a) obtaining a salt of a bis(fluorosulfonyl)imide of formula (I) by the method described above; (b) reacting the bis(fluorosulfonyl)imide salt (I) with an alkaline reagent which is a lithium salt or a cesium salt; The present invention also relates to a method comprising the steps of:

[0021] The present invention also relates to a compound of formula (IV): F-(SO2)-NX3-(SO2)-F (IV) (wherein X3 represents Li or Cs, preferably Li). a salt of a bis(fluorosulfonyl)imide of As well as the use of such salts (IV) in battery electrolyte solutions. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] In this application: - the expressions "between…and…" as well as "from…to…" etc. are to be understood as including limits; - any description, even if made in relation to a particular embodiment, is applicable to and interchangeable with other embodiments of the invention; - when an element or component is said to be included in and / or selected from a list of enumerated elements or components, in the relevant embodiments expressly contemplated herein, the element or component can be any one of the individual enumerated elements or components, or can be selected from a group consisting of any two or more of the explicitly enumerated elements or components; it is to be understood that any element or component enumerated in a list of elements or components may be omitted from such list; - Any recitation herein of numerical ranges by endpoints includes all numbers subsumed within the recited range, as well as the endpoints of the range, and equivalents thereof.

[0023] A first object of the present invention is to provide a compound of formula (I): [F-(SO2)-N - -(SO2)-F] n X1 n+ (I) (In the formula, - X1 n+ is K + , Na + and an onium cation, - n is 1 and represents the valence of the cation A process for preparing a salt of a bis(fluorosulfonyl)imide of the formula: Formula (II): [Cl-(SO2)-N - -(SO2)-Cl] n X1 n+ (II) with anhydrous hydrogen fluoride (III), The process is carried out in the absence of a solvent or in the presence of a solvent in an amount of less than 5% by weight, based on the total weight of the reaction mixture, in a molten salt of a bis(fluorosulfonyl)imide of formula (I) and / or a molten salt of a bis(chlorosulfonyl)imide of formula (II).

[0024] The anhydrous hydrogen fluoride (III) preferably has a high purity, for example, greater than 99.95 mol %, with less than 1000 ppm H2O, less than 10 ppm SO2, less than 100 ppm H2SO4, less than 20 ppm H2SiF6, and less than 25 ppm As.

[0025] The salt (I) described herein is characterized by a low residual amount of solvent, advantageously an undetectable amount of solvent, which makes the salt (I) suitable for many applications, especially battery applications. Indeed, although it is believed that the salt (I) will not be used directly in a battery product, the purity of this intermediate will have a positive impact on the purity of the Li salt used in the battery product, if the Li salt is obtained from such an intermediate.

[0026] The process of the present invention is carried out as a melt in the absence of solvents and diluents. More precisely, the process is carried out in a molten salt of a bis(fluorosulfonyl)imide of formula (I), such as molten KN(SO2F)2 or molten NH4N(SO2F)2, and / or a molten salt of a bis(chlorosulfonyl)imide of formula (II), such as molten NH4N(SO2Cl)2, which acts to disperse the reactants and allows the reactants (II) and (III) to meet and react. Importantly, the process of the present invention is a solvent-free process. In other words, no solvent / diluent is added to the reaction mixture during the reaction, or else only very small amounts of solvent / diluent are added. Firstly, this is advantageous since steps to remove the solvent increase the complexity of the industrial process as well as its overall cost. Secondly, since only anhydrous solvents (characterized by residual amounts of water that are on the order of ppm amounts) can be practically used, the solvent typically needs to be treated before being used in such a process.

[0027] In the context of the present invention, the term "solvent" is intended to mean a compound that exhibits three cumulative properties: 1 / it is present throughout the reaction and is optionally added during the process; 2 / it is not altered during the process, in other words it is non-reactive with the reactants involved; and 3 / it must be removed at the end of the process if the reaction product must be in its highly pure form. Examples of solvents that fall within the scope of this definition are given below. For the sake of clarity, the molten salt of the bis(fluorosulfonyl)imide of formula (I) used in the process of the present invention is not included in the above definition of "solvent". The same applies to the molten salt of the bis(chlorosulfonyl)imide of formula (II) used in the process of the present invention.

[0028] According to one embodiment of the present invention, the method described herein is carried out in the presence of a very small amount of solvent, i.e., less than 5% by weight of solvent based on the total weight of the reaction mixture. Preferably, according to this embodiment, the amount of solvent is less than 4% by weight, less than 3% by weight, less than 2% by weight, less than 1% by weight, less than 0.5% by weight, less than 0.1% by weight, less than 0.01% by weight, or less than 0.001% by weight of solvent based on the total weight of the reaction mixture. The total weight of the reaction mixture is obtained by adding up the weights of the reactants and the weights of the molten salts (I) and / or (II).

[0029] Solvents typically used in such processes are well known and have been described extensively in the literature. Such solvents may be aprotic, e.g. polar aprotic solvents, cyclic and acyclic carbonates, such as ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, cyclic and acyclic esters, such as gamma-butyrolactone, gamma-valerolactone, methyl formate, methyl acetate, methyl propionate, ethyl acetate, ethyl propionate, isopropyl acetate, propyl propionate, butyl acetate, cyclic and acyclic ethers, such as diethyl ether, diisopropyl ether, methyl tert-butyl ether, dimethoxymethane, 1,2-dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxane, 4-methyl-1,3-dioxane, 1,4-dioxane, amide compounds, such as N,N-dimethylformamide, N-methyloxazolidinone, Sulfoxide and sulfone compounds, such as sulfolane, 3-methylsulfolane, dimethylsulfoxide, and - cyano, nitro, chloro or alkyl substituted alkanes or aromatic hydrocarbons, e.g. acetonitrile, valeronitrile, adiponitrile, benzonitrile, nitromethane, nitrobenzene may be selected from the group consisting of:

[0030] Typically, the organic solvent used to carry out such a process may be selected from the group consisting of ethyl acetate, isopropyl acetate, butyl acetate, ethylene carbonate, dimethyl carbonate, ethyl methyl carbonate, propylene carbonate, valeronitrile and acetonitrile, for example as described in the documents listed in the background section.

[0031] According to one embodiment of the process of the present invention, in order to bring the salt of bis(fluorosulfonyl)imide of formula (I), e.g. NH4N(SO2F)2 into a molten state (also called liquid state), a certain amount of the salt is heated to its melting temperature Tm before the addition of the reactant (or reactive substance). (I) The reaction mixture is then heated to a temperature above 100° C. Then, reactants, which may be in powder, slurry, or liquid form, are added to the reaction mixture and reacted to produce a salt of bis(fluorosulfonyl)imide of formula (I), such as NH4N(SO2F)2. The desired product can be produced in molten form and then solidified according to any selected step known to those skilled in the art. This means that the amount of such reaction product (i.e., salt of bis(fluorosulfonyl)imide of formula (I)) increases over the reaction time. In other words, according to this embodiment of the invention, the molten reaction product is used to provide a medium to disperse the reactants and allow them to meet and react. Thus, no solvent is required according to the present invention. This is advantageous since it significantly simplifies the entire production process, since no such solvent needs to be removed after the reaction in order to obtain a high purity bis(fluorosulfonyl)imide salt. It presents the further advantage of not requiring an additional step of removing water instead of the solvent.

[0032] According to another embodiment of the process of the present invention, a quantity of a salt of a bis(chlorosulfonyl)imide of formula (II), such as NH4N(SO2Cl)2, is heated to above 50° C., such as above 60° C., above 70° C., above 80° C., or even above 89° C., prior to the addition of the fluorinating agent (III), i.e., hydrogen fluoride. A fluorinating agent is then added to the reaction mixture and reacted to produce a salt of a bis(fluorosulfonyl)imide of formula (I), such as NH4N(SO2F)2.

[0033] According to yet another embodiment of the process of the present invention, in order to maintain the reaction mixture in a molten state (also called liquid state) during and after the fluorination step, an amount of a salt of a bis(chlorosulfonyl)imide of formula (II), e.g., NH4N(SO2Cl)2, is added to a reaction mixture at a temperature below the melting temperature Tm of the desired product, e.g., NH4N(SO2F)2, before the addition of the fluorinating agent (III), i.e., hydrogen fluoride. (I) The reactants are then reacted to form a salt of the bis(fluorosulfonyl)imide of formula (I), e.g., NH4N(SO2F)2.

[0034] According to the present invention, a salt of bis(chlorosulfonyl)imide (II): [Cl-(SO2)-NH-(SO2)-Cl] n X1 n+ (II) is reacted with anhydrous hydrogen fluoride(III).

[0035] According to the present invention, X1 n+ is K + , Na + or an onium cation, where onium cation has its ordinary meaning to one of ordinary skill in the art.

[0036] Examples of onium cations include phosphonium cations, oxonium cations, sulfonium cations, fluoronium cations, chloronium cations, bromonium cations, iodonium cations, selenonium cations, telluronium cations, arsonium cations, stibonium cations, bismuthonium cations; iminium cations, diazenium cations, nitronium cations, diazonium cations, nitrosonium cations, hydrazonium cations, diazenium dications, diazonium dications, imidazolium cations, pyridinium cations, quaternary ammonium cations, tertiary ammonium cations, secondary ammonium cations, primary ammonium cations, ammonium NH4 + cations include piperidinium cations, pyrrolidinium cations, morpholinium cations, pyrazolium cations, guanidinium cations, isouronium cations and isothiuronium cations.

[0037] Among these, imidazolium cation, pyridinium cation, quaternary ammonium cation, tertiary ammonium cation, secondary ammonium cation, primary ammonium cation, ammonium NH4 + More preferred are the piperidinium cation, the pyrrolidinium cation, the morpholinium cation, the pyrazolium cation, the guanidinium cation, and the isouronium cation.

[0038] Examples of these types of onium cations include: imidazolium cations, such as the 1,3-dimethylimidazolium cation, the 1-ethyl-3-methylimidazolium cation, the 1-propyl-3-methylimidazolium cation, the 1-butyl-3-methylimidazolium cation, the 1-pentyl-3-methylimidazolium cation, the 1-hexyl-3-methylimidazolium cation, the 1-heptyl-3-methylimidazolium cation, the 1-octyl-3-methylimidazolium cation, the 1-decyl-3-methylimidazolium cation, the 1-tetradecyl-3-methylimidazolium cation, midazolium cation, 1-hexadecyl-3-methylimidazolium cation, 1-octadecyl-3-methylimidazolium cation, 1-allyl-3-ethylimidazolium cation, 1-allyl-3-butylimidazolium cation, 1,3-diallyl imidazolium cation, 1-ethyl-2,3-dimethylimidazolium cation, 1-butyl-2,3-dimethylimidazolium cation, 1-hexyl-2,3-methylimidazolium cation, and 1-hexadecyl-2,3-methylimidazolium cation; - pyridinium cations, such as the 1-ethylpyridinium cation, the 1-butylpyridinium cation, the 1-hexylpyridinium cation, the 1-octylpyridinium cation, the 1-ethyl-3-methylpyridinium cation, the 1-ethyl-3-hydroxymethylpyridinium cation, the 1-butyl-3-methylpyridinium cation, the 1-butyl-4-methylpyridinium cation, the 1-octyl-4-methylpyridinium cation, the 1-butyl-3,4-dimethylpyridinium cation and the 1-butyl-3,5-dimethylpyridinium cation; - quaternary ammonium cations, such as tetramethylammonium cation, tetraethylammonium cation, tetrapropylammonium cation, tetrabutylammonium cation, tetraheptylammonium cation, tetrahexylammonium cation, tetraoctylammonium cation, triethylmethylammonium cation, propyltrimethylammonium cation, diethyl-2-methoxyethylmethylammonium cation, methyltrioctylammonium cation, cyclohexyltrimethylammonium cation, 2-hydroxyethyltrimethylammonium cation, trimethylphenylammonium cation, benzyltrimethylammonium cation, benzyltributylammonium cation, benzyltriethylammonium cation, dimethyldistearylammonium cation, diallyldimethylammonium cation, 2-methoxyethoxymethyltrimethylammonium cation, N-methoxytrimethylammonium cation, N-ethoxytrimethylammonium cation, N-propoxytrimethylammonium cation and tetrakis(pentafluoroethyl)ammonium cation; - tertiary ammonium cations, such as trimethylammonium cation, triethylammonium cation, tributylammonium cation, diethylmethylammonium cation, dimethylethylammonium cation, dibutylmethylammonium cation, and 4-aza-1-azoniabicyclo[2.2.2]octane cation; - secondary ammonium cations, such as the dimethylammonium cation, the diethylammonium cation, and the dibutylammonium cation; primary ammonium cations, such as methylammonium cation, ethylammonium cation, butylammonium cation, hexylammonium cation, and octylammonium cation; - Ammonium cation NH4 + ; piperidinium cations, such as the 1-propyl-1-methylpiperidinium cation and the 1-(2-methoxyethyl)-1-methylpiperidinium cation; - pyrrolidinium cations, such as the 1-propyl-1-methylpyrrolidinium cation, the 1-butyl-1-methylpyrrolidinium cation, the 1-hexyl-1-methylpyrrolidinium cation, and the 1-octyl-1-methylpyrrolidinium cation; - morpholinium cations, such as the 4-propyl-4-methylmorpholinium cation and the 4-(2-methoxyethyl)-4-methylmorpholinium cation; - pyrazolium cations, such as the 2-ethyl-1,3,5-trimethylpyrazolium cation, the 2-propyl-1,3,5-trimethylpyrazolium cation, the 2-butyl-1,3,5-trimethylpyrazolium cation, and the 2-hexyl-1,3,5-trimethylpyrazolium cation; guanidinium cations, such as the guanidinium cation and the 2-ethyl-1,1,3,3-tetramethylguanidinium cation; and - isouronium cations, such as the 2-ethyl-1,1,3,3-tetramethylisouronium cation Examples include:

[0039] Quaternary ammonium cations, tertiary ammonium cations, secondary ammonium cations, primary ammonium cations, and ammonium cation NH4 + More preferred are those specifically listed in the above list. Ammonium cation NH4 + is the most preferred onium cation.

[0040] The salt of the bis(fluorosulfonyl)imide of formula (II) is preferably the following salt: Cl-(SO2)-NK-(SO2)-Cl (IIa); Cl-(SO2)-NNa-(SO2)-Cl (IIb), or Cl-(SO2)-NNH4-(SO2)-Cl (IIc) It is one of them.

[0041] One of the reactants (sometimes called feedstocks) involved in the process of the present invention is anhydrous hydrogen fluoride (III).

[0042] Anhydrous hydrogen fluoride can be introduced into the reaction mixture in any form. It can be introduced as a liquid or it can be introduced into the reaction vessel as a gas. It can be introduced into the molten salt (I) and / or (II) in liquid or gas form. It can also be introduced into the reaction vessel as a gas in the gas phase. Anhydrous hydrogen fluoride can be dispersed into the molten salt (I) and / or (II) by any means known to those skilled in the art.

[0043] According to the present invention, the hydrogen fluoride (III) is anhydrous. The water content, as measured, for example, by Karl Fischer water titration carried out in a glove box, can be preferably less than 5,000 ppm, more preferably less than 1,000 ppm, less than 500 ppm, less than 100 ppm, less than 50 ppm or even less than 10 ppm.

[0044] In some embodiments, the stoichiometric amount (also called molar amount) of fluorinating agent (III) to bis(chlorosulfonyl)imide (II) is from 0.1:1 to 20:1, for example, from 1:1 to 10:1, or from 2:1 to 8:1.

[0045] In some embodiments, the stoichiometric amount of the fluorinating agent (III) is 2 or more equivalents per mole of bis(chlorosulfonyl)imide (II), for example, 2 to 10 equivalents per mole of bis(chlorosulfonyl)imide (II). Preferably, the stoichiometric amount of the fluorinating agent (III) is 2 to 8 equivalents per mole of bis(chlorosulfonyl)imide (II), or 3 to 6 equivalents per mole of bis(chlorosulfonyl)imide (II). More preferably, the stoichiometric amount of the fluorinating agent (III) is equal to 4±0.8 equivalents or 4±0.5 equivalents per mole of bis(chlorosulfonyl)imide (II).

[0046] The process of the present invention may be carried out in batch, semi-batch, or continuous mode.

[0047] According to one embodiment, the process is carried out in a continuous or semi-continuous manner and includes a step of continuously or semi-continuously removing the salt of bis(fluorosulfonyl)imide (I) from the reaction mixture. According to the invention, it is possible to semi-continuously add reactants to the reaction mixture and semi-continuously remove reaction products, taking into account the prior removal of residual HF / HCl components between each sequence.

[0048] In some embodiments, the process of the present invention comprises: (i) A process for producing a molten salt of a bis(fluorosulfonyl)imide (I) and / or a molten salt of a bis(chlorosulfonyl)imide of formula (II) by heating an amount Q0 of a salt of a bis(fluorosulfonyl)imide (I) and / or a salt of a bis(chlorosulfonyl)imide of formula (II) at a temperature Ta (°C), wherein the temperature Ta (°C) is: (i1) Melting point Tm of salt (I) (I) a higher temperature, and / or (i2) The temperature is higher than 50° C., for example higher than 60° C. The process and (ii) adding anhydrous hydrogen fluoride (III) in gaseous or liquid form to a reaction vessel, for example to a molten salt of a bis(fluorosulfonyl)imide (I) and / or a molten salt of a bis(chlorosulfonyl)imide of formula (II); (iii) optionally adding a bis(chlorosulfonyl)imide of formula (II) to the molten salt of a bis(fluorosulfonyl)imide (I); Includes.

[0049] The temperature Ta (℃) is the melting point Tm of the bis(fluorosulfonyl)imide salt (I). (I) For example, Ta can be equal to or greater than Tm (I) +2°C or higher, or Ta is equal to or lower than Tm (I) It may be +5°C or higher.

[0050] The temperature Ta (° C.) may be 50° C. or higher.

[0051] One of the reactants, for example the fluorinating agent (III), can be predispersed in the reaction mixture prior to introducing the second reactant, for example the bis(chlorosulfonyl)imide (II).

[0052] In some embodiments, step (ii) may, for example, itself comprise: (ii1) adding hydrogen fluoride (III) to a molten salt of bis(fluorosulfonyl)imide (I); (ii2) adding bis(chlorosulfonyl)imide (II) to the reaction mixture; Includes.

[0053] According to this embodiment, the bis(chlorosulfonyl)imide (II) may be in liquid form and may be added, for example, dropwise, to the reaction mixture.

[0054] According to step (ii2), the bis(chlorosulfonyl)imide (II) can be heated to a temperature Tb(°C) in the range of 30-120°C before being added to the reaction mixture. The temperature Tb(°C) can be, for example, in the range of 50°C-100°C, or 60°C-100°C. According to a particular embodiment, the bis(chlorosulfonyl)imide (II) is heated to a temperature Tb(°C)=Ta(°C)±10°C, for example Ta(°C)±5°C. According to another embodiment, the bis(chlorosulfonyl)imide (II) is heated to a temperature Tb(°C)≦Ta(°C)+10°C, or Tb(°C)≦Ta(°C).

[0055] In some embodiments, step (ii) is adding hydrogen fluoride (III) and bis(chlorosulfonyl)imide (II) simultaneously to the molten salt of bis(fluorosulfonyl)imide (I).

[0056] The addition of reactants (II) and (III) to the molten salt (I) of bis(fluorosulfonyl)imide can usually be carried out sequentially, gradually or continuously, and the total amount of each reactant can also be added to the reactor in increments, for example several times, particularly when the process is carried out batchwise.

[0057] For example, batch reactors, extruders, and kneaders can be used in the present invention. Materials that are resistant to corrosion by acids, such as PTFE or PFA, can be coated (or lined) within selected reactors.

[0058] Reference may be made to industrialized melt mixers or melt blenders.

[0059] The kneader used may comprise any of the known suitable kneaders that can be heated above the melting point of the salt (I) and allow the release of gas products. Suitable kneaders generally have one, or preferably at least two, rotating shafts that are parallel to the axis, the main shafts of which may have areas with kneading elements arranged on their outer surface. The kneader may have rotors that are operated at rotational speeds in the range of 5 to 50 rpm, particularly preferably 7.5 to 40 rpm, in particular 10 to 30 rpm. The advantage of the kneader used in the present invention is that the residence time can be substantially longer than in an extruder. Degassing is even substantially easier and can be carried out to a greater extent, so that gas products can be released more easily. Furthermore, the shear rates of the present invention can be reached more easily in the kneader. Various feeding systems of the reactants can be used in the continuously operated kneader. If molten reactants are required, liquid metering can be used.

[0060] 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. For this purpose, materials that are corrosion resistant, 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 the addition of copper and / or molybdenum sold under the names Inconel® or Monel®, more particularly Hastelloy C276 or Inconel 600, 625 or 718 alloys, are selected for the parts that come into contact with the reaction medium. Stainless steels may also be selected, such as austenitic steels, more particularly 304, 304L, 316 or 316L stainless steels. Steels are used that have a nickel content of up to 22% by weight, preferably between 6% and 20% by weight, more preferentially between 8% and 14% by weight. 304 and 304L steels have a nickel content that varies between 8% and 12% by weight, while 316 and 316L steels have a nickel content that varies between 10% and 14% by weight. More specifically, 316L steel is selected. Equipment made of or coated with polymeric compounds that are resistant to the corrosion of the reaction medium may also be used. In particular, materials such as PTFE (polytetrafluoroethylene or Teflon) or PFA (perfluoroalkyl resins) may be mentioned. Glass equipment may also be used. It would not be outside the scope of the invention to use equivalent materials. Other materials that may be suitable for contacting the reaction medium may also include graphite derivatives. The material for the 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 may be used.

[0061] The process of the present invention can be carried out at atmospheric pressure or under reduced pressure. Preferably, the process of the present invention is carried out under reduced pressure. Carrying out the reaction under reduced pressure is preferred since it facilitates the removal of chlorine atoms from the bis(chlorosulfonyl)imide of formula (II) during the process. There is no particular limit to the pressure that can be applied to the process. The process can be carried out at a pressure varying from 0.5 bar to 3 bar, for example, from 0.7 to 2.5 bar, or from 0.9 to 2 bar.

[0062] Alternatively, the process of the present invention can be carried out using a sealed reactor equipped with a pressure relief means, which is one of the preferred embodiments of the present invention.

[0063] The process of the invention can advantageously be carried out under an inert atmosphere to avoid contamination with moisture, for example under nitrogen or argon.

[0064] The process of the present invention can be carried out at a temperature below 150° C., for example below 125° C., or below 100° C. The process of the present invention is preferably carried out at a temperature below the melting temperature (Tm (I) The reaction can be carried out at temperatures ranging from 100° C. to 150° C.

[0065] The reaction time of the process of the present invention can be freely selected depending on, for example, the reactor used, the required reaction temperature and the amount of reactants. The reaction time is preferably 1 to 12 hours, particularly preferably 1.5 to 10 hours or 2 to 9 hours.

[0066] The process may include a step of heating the amount Q0 of salts (I) and / or (II) so that they are in a molten or substantially molten state. In some embodiments, this step includes heating the amount Q0 of salt (I) of bis(fluorosulfonyl)imide to its melting point Tm (I)In some other embodiments, this step is a step of heating a mixture of salts (I) and (II) in an amount Q0 to a temperature Ta (° C.) or higher to produce a molten salt of bis(fluorosulfonyl)imide (I). ... (I) to a temperature Ta (°C) or higher to produce a molten mixture of salts (I) and (II). The amount Q0 of molten salt should not be less than 20% by weight of the total weight of the reaction mixture when all reactive materials have been added. For example, such amount Q0 may be at least 30% by weight, at least 35% by weight, at least 40% by weight, at least 45% by weight, at least 50% by weight, at least 55% by weight, at least 60% by weight, at least 65% by weight, at least 70% by weight. Such amount Q0 may be less than 95% by weight, less than 90% by weight, or less than 85% by weight. The total weight of the reaction mixture when all reactive materials have been added can be calculated by adding the weight of molten salts (I) and / or (II) to the weight of all reactants involved in the process. According to one embodiment, the amount Q0 is 50±10% by weight of the total weight of the reaction mixture when all reactive materials have been added.

[0067] It is advantageous according to the invention to select the reaction conditions such that at the end of the process the conversion C is at least 95%, particularly preferably at least 98%, in particular at least 99%. For the purposes of the present invention, the conversion C is the molar ratio of reacted reactive groups, i.e. bis(chlorosulfonyl)imide (II) and fluorinating agent (III).

[0068] Surprisingly, it has been found that the conversion of reactants (II) and (III) is very high under the process conditions described herein despite the absence of any solvent or diluent.

[0069] In some preferred embodiments, the process is such that the conversion C is at least 95%, at least 98%, at least 99%, at least 99.5%, at least 99.9% or at least 99.99%.

[0070] The process of the present invention may further comprise cooling the reaction mixture to a temperature Tc(°C) below 80°C, for example below 60°C.

[0071] The process of the present invention optionally further comprises filtering the reaction mixture. The filtering step is to remove reaction by-products and / or impurities, which may be, for example, hydrolysis by-products that are insoluble in the cooled reaction mixture, insoluble by-products that are onium halides, or other by-products known to those skilled in the art.

[0072] Filtration products (funnel, membrane, Nutsche filter or glass filter, dryer...) are preferably used for the filtration.

[0073] According to the present invention, a highly pure or substantially highly pure salt of the bis(fluorosulfonyl)imide of formula (I) is obtained in molten form at the end of the reaction.

[0074] The bis(fluorosulfonyl)imide of formula (I) can be maintained at a temperature such that it remains liquid, but it can also be post-processed to be in powder form, for example in crystallized or precipitated form.The bis(fluorosulfonyl)imide of formula (I) obtained from the process of the present invention can be used in its molten, crystallized or precipitated form.For example, the molten salt of the bis(fluorosulfonyl)imide of formula (I) can be added to a lower temperature organic solvent, for example trifluoroethanol, and can be crystallized before further use.

[0075] According to yet another embodiment, the salt (I) can be at least partially crystallized in the melt, which can then be extracted or reused / recycled in a new reaction cycle. In another embodiment, the molten salt of the bis(fluorosulfonyl)imide of formula (I) can be added to an organic solvent, for example dioxane, and precipitated before further use.

[0076] The process of the present invention also comprises the following reaction parameters: - the molar ratio of bis(chlorosulfonyl)imide (II) to fluorinating agent (III) in the reaction mixture, the number of moles of reactants in the reaction mixture, in particular the number of moles of bis(chlorosulfonyl)imide (II); - the temperature of the reaction mixture (°C), - pressure (atm), - the melt viscosity of the reaction mixture, or - Filling level of reactors, e.g. kneaders The method may also include the additional step of measuring and / or monitoring at least one of

[0077] A second object of the present invention is to provide a compound of formula (I): [F-(SO2)-N - -(SO2)-F] n X1 n+ (I) (In the formula, - X1 n+ is K + , Na + and an onium cation, - n is 1 and represents the valence of the cation It is a salt of bis(fluorosulfonyl)imide.

[0078] Such salts (I) can be advantageously obtained by the process described above.

[0079] The salt of the bis(fluorosulfonyl)imide of formula (I) of the present invention may be, for example, in the molten state, in a crystallized form, or in a precipitated form.

[0080] Advantageously, due to the fact that no solvent is used in the process of the present invention, such salts are highly pure or substantially highly pure, and do not have even traces of solvent or have very small amounts of residual solvent.This is advantageous because the solvents normally used to prepare salt (I) need to be removed after reaction in order to obtain products with as high purity as possible.In fact, only very pure products can be used for battery applications.

[0081] In some preferred embodiments, the amount of solvent in the salt of bis(fluorosulfonyl)imide of formula (I) is less than 100 ppm, such as less than 90 ppm, less than 80 ppm, less than 70 ppm, less than 60 ppm, less than 50 ppm, less than 40 ppm, less than 30 ppm, less than 20 ppm, less than 10 ppm, or even less than 1. This is an advantageous feature of the salt obtained by the process of the present invention. The residual solvent content can be determined by GC, such as headspace GC.

[0082] The salts of the bis(fluorosulfonyl)imides of formula (I) described herein have the formula (I): [F-(SO2)-N - -(SO2)-F] n X1 n+ (I) (In the formula, - X1 n+ is K + , Na + and an onium cation, - n is 1 and represents the valence of the cation A process for preparing a salt of a bis(fluorosulfonyl)imide of the formula: Formula (II): [Cl-(SO2)-NH-(SO2)-Cl] n X1 n+ (II) with anhydrous hydrogen fluoride (III), The reaction mixture is preferably prepared by a process carried out in the absence of a solvent or in the presence of a solvent in an amount of less than 5% by weight, based on the total weight of the reaction mixture, in a molten salt of a bis(fluorosulfonyl)imide of formula (I) and / or a molten salt of a bis(chlorosulfonyl)imide of formula (II).

[0083] Such salts of formula (I) can advantageously be obtained directly from the fluorination of the salts of bis(chlorosulfonyl)imides of formula (II) without additional purification or separation steps.

[0084] The salts of the bis(fluorosulfonyl)imides of formula (I) are preferably the following salts: F-(SO2)-NK-(SO2)-F (Ia), F-(SO2)-NNa-(SO2)-F (Ib), or F-(SO2)-NNH4-(SO2)-F (Ic) It is one of them.

[0085] A filtration step can be used in addition to the above process to remove reaction by-products and / or impurities, which may be, for example, hydrolysis by-products that are insoluble in the cooled reaction mixture, insoluble by-products that are onium halides, or other by-products known to those skilled in the art.

[0086] A preferred embodiment of the present invention is a compound of formula (Ic): F-(SO2)-NNH4-(SO2)-F (Ic) The present invention relates to a salt of ammonium bis(fluorosulfonyl)imide.

[0087] In this preferred embodiment, the salt is free of the following impurities: - NH4Cl, - NH4F, - NH4HF2, - NH4FSO3, - NH4SO3NH2, - NH4[N(SO3H)(SO2F)](OFSI), and / or - NH4[N(SO3H)2](OSI) It may contain at least one of:

[0088] Impurities such as NH4Cl and NH4HF2 may, for example, be present in salt (Ic) in residual amounts of less than 1,000 ppm, less than 500 ppm, less than 200 ppm or less than 100 ppm, preferably less than 90 ppm. Such impurities may be present in salt (Ic) in amounts of more than 1 ppm, for example more than 5 ppm or more than 10 ppm.

[0089] Impurities such as OFSI and OSI may for example be present in salt (Ic) in residual amounts of less than 1,000 ppm, less than 500 ppm, less than 400 ppm or less than 300 ppm, preferably less than 250 ppm or even less than 200 ppm. Such impurities may be present in salt (Ic) in amounts of more than 1 ppm, for example more than 5 ppm or more than 10 ppm.

[0090] The salt (I) of the present invention preferably also has the following contents of chemical substances: - less than 10,000 ppm, preferably less than 5,000 ppm, more preferably less than 1,000 ppm, more preferably less than 500 ppm, more preferably less than 100 ppm, more preferably less than 50 ppm, more preferably less than 20 ppm chloride (Cl - ) content; and / or - Fluoride (F) less than 10,000 ppm, preferably less than 5,000 ppm, more preferably less than 1,000 ppm, more preferably less than 500 ppm, more preferably less than 100 ppm, more preferably less than 50 ppm, more preferably less than 20 ppm - ); and / or - Less than 30,000 ppm, preferably less than 10,000 ppm, more preferably less than 5,000 ppm sulfate (SO4 2- ) content; and / or an iron (Fe) content of less than 1,000 ppm, preferably less than 800 ppm, more preferably less than 500 ppm; and / or - a chromium (Cr) content of less than 1,000 ppm, preferably less than 800 ppm, more preferably less than 500 ppm; and / or a nickel (Ni) content of less than 1,000 ppm, preferably less than 800 ppm, more preferably less than 500 ppm; and / or - a zinc (Zn) content of less than 1,000 ppm, preferably less than 100 ppm, more preferably less than 10 ppm; and / or - a copper (Cu) content of less than 1,000 ppm, preferably less than 100 ppm, more preferably less than 10 ppm; and / or - a bismuth (Bi) content of less than 1000 ppm, preferably less than 100 ppm, more preferably less than 10 ppm; and / or - a sodium (Na+) content of less than 10,000 ppm, preferably less than 5,000 ppm, more preferably less than 500 ppm; and / or - less than 10,000 ppm, preferably less than 5,000 ppm, more preferably less than 500 ppm potassium (K + ) At least one of the following is also shown.

[0091] The fluoride and chloride content can be measured titrimetrically, for example by argentometry using an ion selective electrode (or ISE). The sulfate content can alternatively be measured by ionic chromatography or by turbidimetry.

[0092] The elemental impurity content can be measured, for example, by ICP-AES (inductively coupled plasma), and more specifically, the Na content can be measured by AAS (atomic absorption spectrometry).

[0093] A third object of the present invention is to provide a compound of formula (IV): F-(SO2)-NX3-(SO2)-F (IV) (wherein X3 represents Li or Cs, preferably Li). It is a salt of bis(fluorosulfonyl)imide.

[0094] This method is (a) obtaining a salt of a bis(fluorosulfonyl)imide of formula (I) by a method as described above; (b) reacting the bis(fluorosulfonyl)imide salt (I) with an alkaline reagent which is a lithium salt or a cesium salt; Includes.

[0095] In some embodiments, the present invention provides a method for the preparation of a compound of formula (V): F-(SO2)-NLi-(SO2)-F (V) 1. A process for preparing the lithium salt of a bis(fluorosulfonyl)imide of the formula: (a) obtaining a salt of a bis(fluorosulfonyl)imide of formula (I) by the method described above; (b) reacting the salt of bis(fluorosulfonyl)imide (I) with a lithium salt; The present invention also relates to a method comprising the steps of:

[0096] According to the present invention, highly pure or substantially highly pure salts of the bis(fluorosulfonyl)imides of formula (I), as described above, are obtained.

[0097] According to one embodiment, step (b) can be carried out directly using salt (I), for example in molten form, for example without any additional purification.

[0098] Alternatively, the salt may be purified before carrying out step b). For example, a molten salt of the bis(fluorosulfonyl)imide of formula (I) may be added to an organic solvent, such as trifluoroethanol, which may be a coolant. In that case, the salt (I) is expected to crystallize before carrying out step (b).

[0099] According to yet another embodiment, by choosing a temperature that allows at least partial crystallization of the salt of the bis(fluorosulfonyl)imide of formula (I), the salt (I) can be at least partially crystallized in the melt and then removed or reused / recycled in a new reaction cycle.

[0100] A fourth object of the present invention is to provide a compound of formula (IV): F-(SO2)-NX3-(SO2)-F (IV) (wherein X3 represents Li or Cs, preferably Li). It is a salt of bis(fluorosulfonyl)imide.

[0101] Such salts (IV) are preferably obtainable by the process described above.

[0102] The salt (IV) of the invention also preferably has the following contents of chemical substances: - less than 10,000 ppm, preferably less than 5,000 ppm, more preferably less than 1,000 ppm, more preferably less than 500 ppm, more preferably less than 100 ppm, more preferably less than 50 ppm, more preferably less than 20 ppm chloride (Cl - ) content; and / or - Fluoride (F) less than 10,000 ppm, preferably less than 5,000 ppm, more preferably less than 1,000 ppm, more preferably less than 500 ppm, more preferably less than 100 ppm, more preferably less than 50 ppm, more preferably less than 20 ppm - ); and / or - Less than 30,000 ppm, preferably less than 10,000 ppm, more preferably less than 5,000 ppm sulfate (SO4 2- ) content; and / or an iron (Fe) content of less than 1,000 ppm, preferably less than 800 ppm, more preferably less than 500 ppm; and / or - a chromium (Cr) content of less than 1,000 ppm, preferably less than 800 ppm, more preferably less than 500 ppm; and / or a nickel (Ni) content of less than 1,000 ppm, preferably less than 800 ppm, more preferably less than 500 ppm; and / or - a zinc (Zn) content of less than 1,000 ppm, preferably less than 100 ppm, more preferably less than 10 ppm; and / or - a copper (Cu) content of less than 1,000 ppm, preferably less than 100 ppm, more preferably less than 10 ppm; and / or - a bismuth (Bi) content of less than 1000 ppm, preferably less than 100 ppm, more preferably less than 10 ppm; and / or - a sodium (Na+) content of less than 10,000 ppm, preferably less than 5,000 ppm, more preferably less than 500 ppm; and / or - less than 10,000 ppm, preferably less than 5,000 ppm, more preferably less than 500 ppm potassium (K+ ) At least one of the following is also shown.

[0103] A fifth object of the present invention relates to the use of the salt of a bis(fluorosulfonyl)imide of formula (IV) in a battery electrolyte solution.

[0104] To the extent that the disclosures of any patents, patent applications, and publications incorporated herein by reference conflict with the statements of this application to the extent that a term may be unclear, this statement shall control. EXAMPLES

[0105] The invention will now be described in more detail with reference to the following examples, the purpose of which is merely illustrative and is not intended to limit the scope of the disclosure.

[0106] Example 1 - Formation of NH4FSI salt in molten NH4FSI A pre-dried Hastelloy autoclave equipped with a stirring shaft, four baffles, and a condenser cooled to -5°C was charged with 50 g of NHFSI (252 mmol) using a solid powder addition apparatus under nitrogen flow. The powder was melted at 90°C and stirring was maintained for 0.5 h. 50 g of molten NHFCS1 (216 mmol) was added to the reaction mixture over 1 h using a double-jacketed dropping funnel. After 0.5 h at 90°C, 17.2 g of liquid anhydrous HF (860 mmol) was gradually charged to the vessel under stirring while maintaining the temperature below 100°C and stirring was continued for 2.5 h. A stream of nitrogen was passed through the system for 12 h to expel excess HF.

[0107] Then, 200 g of dioxane was added to the mixture over 1.5 hours while the system was naturally cooled. After another hour with vigorous stirring, the heterogeneous reaction medium was cooled to 25° C. and transferred onto a PTFE filter funnel. The solid cake was isolated by filtration (0.22 μm PTFE membrane). The resulting solid cake was washed with 100 g of fresh 1,4-dioxane. The resulting solid cake was dried under vacuum at room temperature for 12 hours.

[0108] The solid product 19 Analysis by F NMR showed a yield of 92.3% in NH4FSI (79.4 wt.%, 1 % 1,4-dioxane as determined by H-NMR).

[0109] Example 2 - Formation of NH4FSI salt in molten NH4CSI In a pre-dried Hastelloy autoclave preheated to 80° C., equipped with a stirring shaft, four baffles, and a condenser cooled to −5° C., 83.3 g (360 mmol) of molten NH4CSI preheated to 80° C. was charged to the vessel at a rate of about 40 g / h using a double-jacketed dropping funnel. 21.6 g of liquid anhydrous HF (1080 mmol) was charged in portions while maintaining the reaction mixture below 90° C. Stirring was continued at 90° C. for 6 hours. The reaction mixture was stripped with a nitrogen stream for 12 hours.

[0110] Then, 250 g of 1,4-dioxane was added to the reaction mixture with stirring. After 1 hour, the resulting suspension was transferred to a filtration apparatus under nitrogen and the resulting solid was isolated by filtration. The filtrate was then cooled to 10° C. for 2 hours. The crystals were isolated by filtration at 25° C. and then washed with 120 g of fresh 1,4-dioxane. The solid was dried under vacuum at room temperature for 12 hours.

[0111] The solvated solid product, designated as NH4FSI-S1, 19 F NMR analysis revealed that NHFSI (80.1 wt.%, 1 The product showed a yield of 93.4% in a 1,4-dioxane (containing 19.8% by weight) as determined by 1 H-NMR.

[0112] Example 3 - Formation of bis(fluorosulfonyl)imide lithium salt Under nitrogen atmosphere, a solution of 8.8 g of NH4FSI-S1 (0.352 mmol) obtained from Example 1 was dissolved in 60 g of ethyl methyl carbonate (EMC). 14.8 g of solid LiOH.H2O (0.352 mmol) was added to the vessel at room temperature in 10 min. After stirring for 1 h, NH4 + The conversion of the ions (determined by NaOH titration) was more than 90%. The medium was concentrated a first time under reduced pressure (P=20 mbar, T=0° C.). 120 mL of EMC was added and concentrated a second time under the same conditions.

[0113] The concentrated solution was dried under reduced pressure at 30° C. for 24 hours. 5 g of a viscous transparent liquid was obtained. 19 F NMR analysis indicated a purity of >99% by weight, with no other fluorinated species detected.

Claims

1. Formula (I): [F-(SO ２ )-N － -(SO ２ )-F] ｎ X １ ｎ＋ (I) (In the formula, -X １ ｎ＋ Is, K ＋ , Na ＋ and onium cations, - n is 1 and represents the valence of the cation 1. A process for preparing a salt of a bis(fluorosulfonyl)imide of the formula: Formula (II): [Cl-(SO ２ )-N － -(SO ２ )-Cl] ｎ X １ ｎ＋ (II) with anhydrous hydrogen fluoride (III), A process carried out in the absence of a solvent or in the presence of a solvent in an amount of less than 5% by weight, based on the total weight of the reaction mixture, in a molten salt of a bis(fluorosulfonyl)imide of formula (I) and / or a molten salt of a bis(chlorosulfonyl)imide of formula (II).

2. 10. The process of claim 1 carried out at atmospheric pressure and / or using a closed reactor having a pressure release means.

3. 3. The process according to claim 1, wherein the stoichiometric amount of hydrogen fluoride (III) is 1 to 10 equivalents per mole of bis(chlorosulfonyl)imide (II).

4. (i) Quantity Q ０ A process for producing a molten salt of bis(fluorosulfonyl)imide (I) and / or a molten salt of bis(chlorosulfonyl)imide of formula (II) by heating a salt of bis(fluorosulfonyl)imide (I) and / or a salt of bis(chlorosulfonyl)imide of formula (II) at a temperature Ta (°C), wherein the temperature Ta (°C) is: (i1) The melting point Tm of the salt (I) （Ｉ） a higher temperature, and / or (i2) a temperature greater than 50°C; The process and (ii) adding anhydrous hydrogen fluoride (III) to the molten salt of the bis(fluorosulfonyl)imide (I) and / or the molten salt of the bis(chlorosulfonyl)imide of formula (II); (iii) optionally adding the bis(chlorosulfonyl)imide of formula (II) to the molten salt of bis(fluorosulfonyl)imide (I); 3. The method of claim 1 or 2, comprising:

5. Step (ii) is (ii1) adding the anhydrous hydrogen fluoride (III) to the molten salt; (ii2) optionally adding the bis(chlorosulfonyl)imide (II) to the reaction mixture; The method of claim 4, comprising:

6. When all the reactive materials have been added, the amount Q ０ is 20 wt. % or more of the total weight of the reaction mixture.

7. 3. The method of claim 1 or 2, carried out at a temperature below 100°C.

8. X １ ｎ＋ NH ４ ＋ The method according to claim 1 or 2, wherein

9. Formula (Ic) [F-(SO ２ )-N － -(SO ２ )-F] ｎ NH ４ ＋ (Ic) 3. A process according to claim 1 or 2 for preparing the ammonium salt of a bis(fluorosulfonyl)imide of formula (IIc): [Cl-(SO ２ )-N － -(SO ２ )-Cl] ｎ NH ４ ＋ (IIc) with anhydrous hydrogen fluoride (III), A process carried out in the absence of a solvent or in the presence of an amount of solvent of less than 5% by weight, based on the total weight of the reaction mixture, in a molten salt of ammonium bis(fluorosulfonyl)imide (cI) and / or a molten salt of ammonium bis(chlorosulfonyl)imide of formula (IIc).

10. 3. A compound of formula (I): [F-(SO ２ )-N － -(SO ２ )-F] ｎ X １ ｎ＋ (I) (In the formula, -X １ ｎ＋ Is, K ＋ , Na ＋ and onium cations, - n is 1 and represents the valence of the cation a salt of a bis(fluorosulfonyl)imide of the formula The amount of said solvent is less than 100 ppm.

11. 11. The salt of claim 10, wherein the amount of solvent is less than 50 ppm.

12. Formula (V) F-(SO ２ )-NX ３ -(SO ２ )-F (IV) (In the formula, X ３ represents Li or Cs, preferably Li) 1. A process for preparing an alkali salt of a bis(fluorosulfonyl)imide of the formula: (a) obtaining a salt of the bis(fluorosulfonyl)imide of formula (I) by the method of claim 1 or 2; (b) reacting the salt of the bis(fluorosulfonyl)imide of formula (I) with an alkaline reagent containing a lithium salt and / or a cesium salt; A method comprising:

13. 13. The process according to claim 12, wherein step (b) is carried out in an organic reaction medium comprising at least one organic solvent, said organic solvent being selected from aprotic organic solvents, preferably from the group consisting of ethyl acetate, isopropyl acetate, butyl acetate, ethylene carbonate, dimethyl carbonate, ethyl methyl carbonate, propylene carbonate, valeronitrile and acetonitrile.

14. 13. Use of the salt of bis(fluorosulfonyl)imide of formula (IV) obtained from the process according to claim 12 in a battery electrolyte solution.

15. A battery article or battery component comprising a salt of a bis(fluorosulfonyl)imide of formula (IV) obtained from the process of claim 12.