Method for producing a fluorine- and sulfur-bearing compound and salts thereof in an aqueous medium

Abstract

The invention relates to a method for producing a fluorine- and sulphur-bearing compound of formula F—SO—R (I) or F—SO.sub.2—R (II), comprising the reaction, in the presence of water, of at least one salt providing a fluoride anion and at least one halgoenosulfoxide compound of formula X—SO—R′ (I0) from a halogenosulfonyl compound of formula X—SO.sub.2—R′ (II0), in which X is a halogen atom other than fluorine and R and R′ are each a group linked by a covalent bond to the sulphur atom, said bond linking the sulphur atom with a nitrogen atom. The invention also relates to a method for producing salts of a fluorine- and sulphur-bearing compound of formula F—SO—R (I) or F—SO.sub.2—R (II) which are advantageously used as electrolyte salts, as precursors of antistatic agents or as surfactant precursors.

Claims

1. A process for preparing a fluorine-containing and sulfur-containing compound of formula F—SO.sub.2—R (II), the process comprising the reaction, in the presence of water, of at least one salt providing a fluoride anion, wherein the salt providing a fluoride anion is potassium fluoride, and of a halosulfonyl compound of formula X—SO.sub.2—R′ (II0), where X is chlorine, R is an —NM′SO.sub.2F group, M′ being potassium, and R′ is an —NHSO.sub.2X group; wherein the H.sub.2O/KF mole ratio is from 2.3 to 2.8, the molar equivalent of KF is from 10 to 20.8, the reaction temperature is 50° C. to 100° C., and the reaction time is between 0.5 hr and under 10 hr.

2. The process as defined in claim 1, further comprising: a step of liquid/liquid extraction, and then the implementation of a sequence comprising the steps of acidification, of recovery of the acid obtained and of neutralization.

3. The process as claimed in claim 1, further comprising: a step of liquid/liquid extraction, and then the implementation of a cation exchange reaction.

4. The process for preparing at least one salt of a fluorine-containing and sulfur-containing compound of formula (II) as claimed in claim 2, wherein said salt of said fluorine-containing and sulfur-containing compound of formula (II) is a salt of potassium.

5. The process for preparing at least one salt of a fluorine-containing and sulfur-containing compound of formula (II) as claimed in claim 3, wherein said salt of said fluorine-containing and sulfur-containing compound of formula (II) is a salt of potassium.

Description

EXAMPLES 1 to 5

(1) A solution of potassium fluoride in aqueous solution is brought to the reaction temperature in a glass reactor. Bis(chlorosulfonyl)imide, denoted HCSI, (10 grams, 47 mmol) is added over the course of 30 seconds and stirring is maintained for 2 hours at the reaction temperature. The reaction medium is diluted in water for the analysis carried out by .sup.19F NMR in order to calculate the yield of potassium bis(fluorosulfonyl)imide (KFSI).

(2) The following table collates the operating conditions used and the results obtained:

(3) TABLE-US-00001 KF HCSI KFSI Example stoichiometry H.sub.2O/KF Temperature conversion yield No. (equivalents) mole ratio (° C.) (%) (%) 1 10 2.8 100 100% 38% 2 10 2.7 75 100% 51% 3 10 2.3 50 100% 65% 4 15 2.4 50 100% 60% 5 20.8 2.5 50 100% 65%

EXAMPLE 6 (comparative)

Fluorination with Zinc Fluoride in an Organic Medium

(4) Zinc fluoride (5.1 g; 49 mmol) is dissolved in 90 grams of valeronitrile. Bis(chlorosulfonyl)imide is then added and stirring is maintained for 24 hours at ambient temperature.

(5) An NMR analysis shows a 100% conversion of the bis(chlorosulfonyl)imide, and the yield of bis(fluorosulfonyl)imide zinc salt is 12%.

EXAMPLE 7

(6) A solution of potassium fluoride (27 g, 0.46 mol) in aqueous solution (23 g of water) is brought to the temperature of 100° C. in a glass reactor. The potassium bis(chlorosulfonyl)imide, denoted KCSI, (11.8 grams, 46 mmol) is added over the course of 30 seconds and stirring is maintained for 2 hours at this reaction temperature. The reaction medium is diluted in water and brought back to ambient temperature. The .sup.19F NMR analysis indicates that the potassium bis(fluorosulfonyl)imide (KFSI) yield obtained is 69%.

EXAMPLE 8

(7) N,N,N-tri-n-octyl-N-methylammonium bis(chlorosulfonyl)imide (27 g; 46 mmol) is added to a solution of potassium fluoride (27 g, 0.46 mol) in water (23 g) brought to a temperature of 120° C. The medium is left to stir for two hours. After a return to ambient temperature, the .sup.19F NMR analysis indicates that the N,N,N-tri-n-octyl-N-methylammonium bis(fluorosulfonyl)imide yield is 49%.

EXAMPLE 9

(8) Potassium bis(chlorosulfonyl)imide (10 g; 46 mmol) is added to a solution of potassium fluoride (27 g, 0.46 mol) in water (23 g) brought to a temperature of 120° C. The medium is left to stir for 30 minutes. After a return to ambient temperature, the .sup.19F NMR analysis indicates that the potassium bis(fluorosulfonyl)imide yield is 76%.