Process for preparing fluorohalogenethers

Abstract

A process for preparing perfluorovinylethers having general formula:

Description

Claims

1. A process for preparing perfluorovinylethers having general formula: RfO—CF═CF2   (IA)wherein Rf is a C1-C3, preferably C1-C2, alkyl perfluorinated substituent;

2. A process according to claim 1, wherein, when in the step 1a) the fluorohalogencarbon (III) is a symmetric organic compound with Y═Cl and Y′═Y″, the impurity of the asymmetric isomer is lowered by carrying out the step:

3. A process according to claim 1, wherein in step 1a) the fluorination reaction takes place by addition of gaseous fluorine, optionally in the presence of an inert diluent, to the olefins of formula (II), liquid at the reaction temperature.

4. A process according to claim 3, wherein a solvent or a mixture of inert solvents and in the liquid state is used.

5. A process according to claim 1, wherein step 1a) is carried out at temperatures between −120° C. and +10° C., preferably −90° C. and −15° C.

6. A process according to claim 1, wherein the olefins of formula (II) are selected from tetrachloroethylene, trichloroethylene, 1,2-dichloroethylene and 1,1-dichloroethylene.

7. A process according to claim 1, wherein in step b 2a) the dehalogenation is carried out by reaction with transition metals, preferably zinc, copper, manganese or metal couples, preferably selected from Zn/Cu, Zn/Hg, in the presence of hydrogenated protic or hydrogenated ether solvents, or dipolar aprotic solvents.

8. A process according to claim 1, wherein in step 2a) the dehydrohalogenation is carried out by reacting fluorohalogencarbons of formula (III) with an inorganic or an organic base.

9. A process according to claim 8, wherein when aqueous inorganic bases are used, the reaction is carried out in the presence of a quaternary ammonium salt or in the presence of phosphonium salts and/or sulphonium salts.

10. A process according to claim 1, wherein in step 2a) one operates at temperatures in the range 0° -150° C., preferably 25° -100° C.

11. A process according to claim 1, wherein compounds (III) usable in step 2a) are selected from CCl2F—CCl2F, CHClF—CHC1F, CCl2-CHClF, CH2F—CCl2F.

12. A process according to claim 1, wherein step 3a) is carried out in liquid phase at temperatures between −130° C. and 0° C., preferably −100° C. and −40° C., optionally in the presence of an organic solvent.

13. A process according to claim 1, wherein step 3a) is carried out by feeding in the reactor containing the olefin at the liquid state, optionally diluted with an solvent inert under the reaction conditions, the hypo-fluorite, prepared in liquid or gaseous phase, diluted in a compound inert under the reaction conditions.

14. A process according to claim 1, wherein in step 3a) compounds (IV) are used selected from CFCl═CFCl and CHF═CFC1.

15. A process according to claim 1, wherein in steps 1a) and 3a) solvents selected from the following are used: (per)fluoropolyethers, (per)fluoroalkanes, HFC, HCFC, CFC, perfluoroamines, hydrofluoroethers or hydrofluoropolyethers or mixtures thereof.

16. A process according to claim 1, wherein in step 4a) the dehalogenation is carried out by reaction with transition metals, preferably zinc, copper, manganese, or metal couples, preferably selected from Zn/Cu, Zn/Sn, Zn/Hg, in the presence of hydrogenated protic, hydrogenated ether solvents, or dipolar aprotic solvents.

17. A process according to claim 1, wherein in step 4a) the dehydrohalogenation is carried out by reaction with an inorganic or an organic base.

18. A process according to claim 17, wherein, when aqueous inorganic bases are used, the reaction is carried out in the presence of a quaternary ammonium salt or in the presence of phosphonium salts and/or sulphonium salts.

19. A process according to claim 1, wherein in step 4a) one operates at temperatures in the range 0°-150° C., preferably 25°-100° C.

20. A process according to claim 1, achievable in a discontinuous, semicontinuous or continuous way.