METHOD FOR PREPARING OXYSULPHIDE AND FLUORINATED DERIVATIVES IN THE PRESENCE OF AN ORGANIC SOLVENT

Abstract

The present invention concerns a method for preparing an oxysulphide and fluorinated derivative of formula (III) Ea-SO.sub.3R (III) that comprises bringing a compound of formula (II) Ea-SOOR (II)Ea representing the fluorine atom or a group having 1 to 10 carbon atoms chosen from the fluoroalkyls, the perfluoroalkyls and the fluoroalkenyls; andR representing hydrogen, a monovalent cation or an alkyl group; into contact, in the presence of a polar aprotic organic solvent, with an oxidising agent.

Claims

1. A process for the preparation of an oxysulfide and fluorinated derivative of formula (III)
Ea-SO.sub.3R (III) comprising bringing into contact, in the presence of an organic polar aprotic solvent, a compound of formula (II)
Ea-SOOR (II) Ea representing a fluorine atom or a group having from 1 to 10 carbon atoms, selected from fluoroalkyls, perfluoroalkyls and fluoroalkenyls; and R representing hydrogen, a monovalent cation or an alkyl group; with an oxidizing agent.

2. The process as claimed in claim 1, in which the reaction medium does not contain aqueous solvent.

3. The process as claimed in claim 1, in which the reaction medium comprises a water content less than or equal to 10% by weight.

4. The process as claimed in claim 1, in which said organic polar aprotic solvent is an amide type solvent.

5. The process as claimed in claim 4, in which said organic polar aprotic solvent is selected from the group consisting of N,N-dimethylformamide (DMF), N,N-diethylformamide (DEF), N-methylpyrrolidone (NMP) or N,N-dimethylacetamide (DMAC).

6. The process as claimed in claim 5, in which said organic polar aprotic solvent is N,N-dimethylformamide (DMF).

7. The process as claimed in claim 1, in which said oxidizing agent is selected from aqueous hydrogen peroxide; percarbonates; persulfates; and hydrogen peroxide-urea.

8. The process as claimed in claim 1, in which R represents a monovalent cation selected from alkali metal cations, quaternary ammonium and quaternary phosphonium cations.

9. The process as claimed in claim 1, in which Ea is selected from a fluorine atom, the CH.sub.2F radical, the CHF.sub.2 radical, the C.sub.2F.sub.5 radical and the CF.sub.3 radical.

10. The process as claimed in claim 1, in which the progression of the oxidation reaction is monitored in-line or in situ by Raman spectrometry, by near infrared spectrometry or by UV spectroscopy.

11. The process as claimed in claim 1, for the preparation of a trifluoromethylsulfonate alkali metal salt.

12. A process for the preparation of an oxysulfide and fluorinated derivative of formula (III)
Ea-SO.sub.3R (III) with: Ea representing a fluorine atom or a group having from 1 to 10 carbon atoms, selected from fluoroalkyls, perfluoroalkyls and fluoroalkenyls; and R representing hydrogen, a monovalent cation or an alkyl group; comprising at least the consecutive steps of: (i) bringing into contact, in the presence of an organic polar aprotic solvent, a compound of formula Ea-COOR (I) with a sulfur oxide, in order to obtain a compound of formula Ea-SOOR (II); and (ii) adding, to the reaction mixture obtained at the end of step (i) of sulfination, an oxidizing agent, in order to obtain the derivative of formula (III).

13. The process as claimed in claim 12, in which the reaction medium of steps (i) and (ii) comprises a water content less than or equal to 10% by weight.

14.-21. (canceled)

22. A process for the preparation of a fluorinated derivative of sulfonic acid of formula (IV)
Ea-SO.sub.3H (IV) Ea representing a fluorine atom or a group having from 1 to 10 carbon atoms, selected from fluoroalkyls, perfluoroalkyls and fluoroalkenyls; comprising at least the following steps: preparation of an oxysulfide and fluorinated derivative of formula Ea-SO.sub.3R (III), R representing a monovalent cation or an alkyl group, in an organic solvent S1 according to the process of claim 1; and acidification of the compound of formula (III) in order to obtain the desired fluorinated derivative of sulfonic acid of formula (IV).

23.-28. (canceled)

29. The process as claimed in claim 22, for the preparation of trifluoromethanesulfonic acid.

30. A process for the preparation of an anhydride compound of formula (V)
(Ea-SO.sub.2).sub.2O (V) Ea representing a fluorine atom or a group having from 1 to 10 carbon atoms, selected from fluoroalkyls, perfluoroalkyls and fluoroalkenyls; comprising at least the following steps: preparation of a fluorinated derivative of sulfonic acid of formula Ea-SO.sub.3H according to the process of claim 1; and anhydrization of the compound of formula Ea-SO.sub.3H in order to obtain said desired anhydride compound of formula (V).

31. The process as claimed in claim 30, for the preparation of trifluoromethanesulfonic anhydride.

32. The process as claimed in claim 7, in which said oxidizing agent is sodium or potassium percarbonate.

33. The process as claimed in claim 7, in which said oxidizing agent is potassium persulfate.

34. The process as claimed in claim 8, in which R represents an alkali metal cation.

Description

EXAMPLES

[0175] The degree of conversion of a reagent corresponds to the ratio of the molar amount of reagent consumed (converted) during a reaction to the initial amount of reagent.

[0176] The product yield from a reagent corresponds to the ratio of the molar amount of product formed to the molar amount of initial reagent.

Example 1

Preparation of Potassium Trifluoromethylsulfonate by Oxidation of Potassium Trifluoromethylsulfinate by H.SUB.2.O.SUB.2 .in N,N-dimethylformamide (DMF)

i. Preparation of Potassium Trifluoromethylsulfinate (CF.SUB.3.SOOK) by Sulfination of Potassium Trifluoroacetate (CF.SUB.3.COOK) in N,N-dimethylformamide (DMF)

[0177] The following are introduced at room temperature into a 500 ml jacketed reactor equipped with a condenser having an aqueous glycol solution at 15 C., with a stirrer and with baffles: [0178] 200 g of anhydrous N,N-dimethylformamide (DMF); [0179] 50 g of potassium trifluoroacetate (KTFA), i.e. a KTFA concentration equal to 20% by weight in the DMF-KTFA mixture.

[0180] The reactor is equipped with a Raman probe which makes it possible to monitor, in the medium, the concentration of dissolved SO.sub.2; this probe is connected by an optical fiber to the Raman spectrometer.

[0181] The medium is stirred and brought to a temperature of 100 C.

[0182] Via a dip pipe connected to a pressurized sulfur dioxode cylinder, an amount of 1.25 g of gaseous SO.sub.2 is continuously introduced into the reactor through a micrometric regulating valve, so as to have a concentration of dissolved SO.sub.2 equal to 0.5% by weight and an initial SO.sub.2/KTFA molar ratio of 0.059.

[0183] The temperature is brought to 145 C. while keeping the SO.sub.2 concentration constant at 0.5% by weight. The reaction is allowed to take place for 5 hours while regulating the SO.sub.2 concentration at 0.5% by weight.

[0184] After 5 hours, the reaction mixture is cooled and analyzed by NMR, and the results are as follows: [0185] Degree of conversion of the potassium trifluoroacetate: 90%; [0186] Yield of potassium trifluoromethylsulfinate: 64.8%.

ii. Oxidation of the Potassium Trifluoromethylsulfinate by Aqueous Hydrogen Peroxide in DMF

[0187] The solution resulting from the sulfination reaction of potassium trifluoroacetate in DMF, prepared as described in point i. above, with a total weight of 267.19 g, is brought to 60 C., then an aqueous solution of aqueous hydrogen peroxide (titer by weight=30%) is added to it over three hours.

[0188] The total amount of aqueous hydrogen peroxide used is two molar equivalents relative to the content of potassium trifluoromethylsulfinate.

[0189] The medium is then maintained at 60 C. for an additional 2 hours and 51 minutes, during which monitoring by in situ Raman spectrometry makes it possible to monitor the evolution of the species.

[0190] At the end of this maintenance time, the content of residual peroxides is monitored and analysis, by .sup.19F NMR, of an aliquot makes it possible to establish that the yield of potassium trifluoromethylsulfonate is 98.44%.

Example 2

Preparation of Potassium Trifluoromethanesulfonate by Oxidation of Potassium Trifluoromethanesulfinate by Sodium Percarbonate in DMF

[0191] A suspension of sodium percarbonate (20.8 g) in DMF is brought to 60 C., then a solution resulting from the sulfination reaction of potassium trifluoroacetate in DMF, prepared as described in the preceding example 1, with a total weight of 176.73 g, is added over this medium in 2-3 hours.

[0192] At the end of this maintenance time, the content of residual peroxides is monitored and analysis, by .sup.19F NMR, of an aliquot makes it possible to establish that the yield of potassium trifluoromethylsulfonate is 90.7%.

Example 3

Preparation of Triflic and Trifluoroacetic Acids

[0193] The reaction medium obtained at the end of the oxidation according to the preceding example 2 is distilled under reduced pressure (160 mbar) then decalin is added to it (200 ml, mixture of isomers). The distillation is continued by means of a Dean-Stark apparatus which makes it possible to regularly draw off the distilled DMF until the boiler is exhausted. The total weight of distilled DMF is 164.1 g.

[0194] 150 ml of oleum at 20% are then added, and the sulfuric phase is drawn off.

[0195] The sulfuric phase is then distilled under reduced pressure, in order to lead to 9.4 g of pure trifluoroacetic acid (CF.sub.3COOH) and 17.6 g of pure triflic acid (CF.sub.3SO.sub.3H), respectively.