# US 10,122,048 B2 · Method for preparing bis(fluorosulfonyl)imide acid and salts thereof

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- Number: US 10,122,048 B2
- Document ID: US10122048B2
- Status: Granted
- Kind: B2
- Application number: 15/101,149
- Filed: 2014-12-03
- Published: 2016-10-20
- Granted: 2018-11-06
- Earliest claimed: 2013-12-05
- Assignees: Rhodia Operations
- Applicants: Rhodia Operations
- Inventors: Olivier Buisine
- Web page: https://patentgrep.com/patent/US10122048B2

## CPC

- H01M 10/0568: characterised by the solutes
- C01B 21/086: containing one or more sulfur atoms
- C01B 21/093: containing also one or more sulfur atoms
- C01B 21/0935: {Imidodisulfonic acid; Nitrilotrisulfonic acid; Salts thereof}
- H01M 2300/0025: Organic electrolyte
- Y02E 60/10: Energy storage using batteries
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

The invention relates to a method for preparing bis(fluorosulfonyl)imide acid, comprising: the reaction of sulphamic acid or one of the salts thereof with a halogenosulfuric acid and at least one fluorinating agent selected from SOF2, F—SO2—F and SF4, and the subsequent recovery of bis(fluorosulfonyl)imide acid. The invention also relates to a method for producing salts of bis(fluorosulfonyl)imide from the bis(fluorosulfonyl)imide acid thus produced.

## Claims

### Claim 1

A process for preparing bis(fluorosulfonyl)imide acid of formula F—SO2—NH—SO2—F, the process comprising the reaction of sulfamic acid or a salt thereof with at least one halosulfuric acid and at least one fluorinating agent selected from the group consisting of SOF2, F—SO2—F and SF4, then the recovery of the bis(fluorosulfonyl)imide acid.

### Claim 2 (depends on 1)

The process for preparing bis(fluorosulfonyl)imide acid as claimed in claim 1, wherein the halosulfuric acid has the formula X—SO2—OH wherein X is a halogen selected from the group consisting of fluorine, chlorine, bromine and iodine.

### Claim 3 (depends on 1)

The process for preparing bis(fluorosulfonyl)imide acid as claimed in claim 1, wherein said reaction is carried out in the presence of an organic solvent.

### Claim 4 (depends on 1)

The process for preparing bis(fluorosulfonyl)imide acid as claimed in claim 1, wherein the halosulfuric acid represents from 1 mol % to 5 molar equivalents expressed relative to the sulfamic acid or salts thereof and the fluorinating agent is F—SO2—F.

### Claim 5 (depends on 4)

The process for preparing bis(fluorosulfonyl)imide acid as claimed in claim 4, wherein the halosulfuric acid represents from 5 mol % to 1 molar equivalent expressed relative to the sulfamic acid or salts thereof.

### Claim 6 (depends on 1)

The process for preparing bis(fluorosulfonyl)imide acid as claimed in claim 1, wherein the halosulfuric acid represents from 1 to 5 molar equivalent(s) expressed relative to the sulfamic acid or salts thereof and the fluorinating agent is SOF2 or SF4.

### Claim 7 (depends on 1)

The process for preparing bis(fluorosulfonyl)imide acid as claimed in claim 1, wherein said fluorinating agent represents from 1 to 10 molar equivalent(s) expressed relative to the sulfamic acid or salts thereof.

### Claim 8 (depends on 1)

The process for preparing bis(fluorosulfonyl)imide acid as claimed in claim 1, wherein said reaction is performed at a temperature between 0 and 180° C.

### Claim 9 (depends on 1)

The process for preparing bis(fluorosulfonyl)imide acid as claimed in claim 1, wherein said bis(fluorosulfonyl)imide acid is recovered by distillation, by sublimation or by extraction.

### Claim 10 (depends on 1)

A process for preparing at least one bis(fluorosulfonyl)imide salt, the process comprising preparing the bis(fluorosulfonyl)imide acid according to the process as defined in claim 1, followed by bringing said acid into contact with at least one salification agent.

### Claim 11 (depends on 10)

The process for preparing at least one bis(fluorosulfonyl)imide salt as claimed in claim 10, wherein the salification agent is a metal hydroxide, a metal halide, a metal hydride, a metal trifluoroacetate or a metal trifluoromethanesulfonate.

### Claim 12 (depends on 10)

The process for preparing at least one bis(fluorosulfonyl)imide salt as claimed in claim 10, wherein said salt has the general formula F—SO2—N-M-SO2—F, where M represents an alkali metal, an alkaline-earth metal, a transition metal or a metal selected from lanthanides.

### Claim 13 (depends on 10)

The process for preparing at least one bis(fluorosulfonyl)imide salt as claimed in claim 10, wherein said salt is lithium bis(fluorosulfonyl)imide.

### Claim 14 (depends on 10)

The process for preparing at least one bis(fluorosulfonyl)imide salt as claimed in claim 10, also comprising a step of purifying said salt.

### Claim 15 (depends on 14)

The process for preparing at least one bis(fluorosulfonyl)imide salt as claimed in claim 14, wherein the purification step consists of a recrystallization.