Process for preparing fluorohalogenethers

Abstract

A process for preparing fluorovinylethers having general formula:

Description

Claims

1. A process for preparing perfluoroalkylvinylethers having general formula: RfO—CF═CF2  (IA)wherein Rf is a C1-C3, preferably C1-C2,perfluorinated substituent;comprising the following steps:1) reaction of a hypofluorite of formula RfOF, wherein Rf is as above, with an olefine of formula: CY″Y═CY″Cl  (II)wherein Y, Y′ and Y″, equal to or different from each other, are H, Cl, Br, with the proviso that Y, Y′ and Y″ are not contemporaneously hydrogen;2) dehalogenation or dehydrohalogenation of the fluorohalogenethers obtained in step 1) and obtainment of vinyl ethers of formula: RfO—CYI═CYIIF  (IV)wherein YI and YII, equal to or different from each other, have the meaning of H, Cl, Br with the proviso that YI and YII are not both H;3) fluorination with fluorine of the vinyl ethers (IV) and obtainment of fluorohalogenethers of formula: RfO—CFYI—CF2YII  (I)wherein YI, YII, equal to or different from each other, are Cl, Br, H with the proviso that YI and YII cannot be contemporaneously equal to H; Rf is as above;4) dehalogenation or dehydrohalogenation of the fluorohalogenethers of formula (I) and obtainment of vinyl ethers of formula: RfO—CF═CF2  (IA).

2. A process according to claim 1, wherein step 1) is carried out in liquid phase at temperatures from −130° C. to 0° C., preferably from −80° C. to −10° C., optionally in the presence of organic solvents.

3. A process according to claim 1, wherein the olefins (II) are selected from the following: tetrachloroethylene, trichloroethylene, 1,2-dichloroethylene and 1,1-dichloroethylene.

4. A process according to claim 1, wherein in step 2) the dehalogenation is carried out with transition metals preferably selected from zinc, copper, manganese or with metal couples, preferably Zn/Cu, Zn/Sn, Zn/Hg, in the presence of solvents selected from hydrogenated protics, hydrogenated ethers, dipolar aprotic solvents.

5. A process according to claim 1, wherein in step 2) the dehydrohalogenation is carried out with an inorganic or an organic base.

6. A process according to claim 5, wherein the dehydrohalogenation is carried out in the presence of a quaternary ammonium or phosphonium salt, preferably selected from ammonium tetrabutyl, ammonium trioctyl benzyl, phosphonium tetrabutyl and phosphonium trioctyl benzyl.

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

8. A process according to claim 1, wherein in step 3) the reaction is carried out by addition of gaseous fluorine, optionally in the presence of an inert diluent, to the compounds of formula (IV), liquid at the reaction temperature, by optionally using a solvent or a mixture of inert solvents being at the liquid state under the conditions in which step 3) is carried out.

9. A process according to claim 1, wherein in step 3) one operates at temperatures between −120° C. and 0° C., preferably −90° C. and −30° C.

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

11. A process according to claim 1, wherein in step 4) the dehalogenation is carried out with transition metals preferably selected from zinc, copper, manganese or with metal couples, preferably Zn/Cu, Zn/Sn, Zn/Hg, in the presence of solvents selected from the following: hydrogenated protics, hydrogenated ethers, dipolar aprotic solvents.

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

13. A process according to claim 12, wherein the dehydrohalogenation is carried out in the presence of a quaternary ammonium or phosphonium salt, preferably selected from ammonium tetrabutyl, ammonium trioctyl benzyl, phosphonium tetrabutyl and phosphonium trioctyl benzyl.

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

15. A process according to claim 1, carried out in a discontinuous, semicontinuous or continuous way.