Process for the preparation of a halogenoacetyl fluoride and its derivatives

摘要

The present invention relates to a method for preparing a halogenoacetyl fluoride and the derivatives thereof. The inventive method for preparing a halogenoacetyl fluoride acid is characterized in that said method includes: a step of preparing a halogenoacetyl halide by photo-oxidation of a halogenoethylene compound in conditions such that the transformation rate of the halogenoethylene compound into halogenoacetyl halide is no higher than 80%, producing a reaction mixture essentially including halogenoacetyl halide and the excess halogenoethylene compound; a step of partial fluorination of the mixture obtained by reacting the latter with hydrofluoric acid suitable for obtaining a mixture of halogenoacetyl fluoride and the excess halogenoethylene compound; a step of separating the halogenoacetyl fluoride and the excess halogenoethylene compound. The invention can be used, specifically, for preparing the trichloroacetyl fluoride used as an intermediate species in the production of trifluoroacetic acid.

主权项

1. A process for preparing a halogenoacetyl fluoride, the process comprising:
step 1)—preparing a halogenoacetyl halide by photooxidation of a chlorinated or brominated ethylenic compound under conditions such that said chlorinated or brominated ethylenic compound is converted to said halogenoacetyl halide with a conversion of at most equal to 80%, resulting in a reaction mixture comprising said halogenoacetyl halide and excess chlorinated or brominated ethylenic compound, wherein the halogenoacetyl in said halogenoacetyl halide is selected from the group consisting of chloroacetyls and bromoacetyls, and wherein the halide in said halogenoacetyl halide is a chloride or a bromide; step 2)—partially fluorinating said reaction mixture obtained by said step 1) by reaction of said reaction mixture with hydrofluoric acid, to obtain a mixture of halogenoacetyl fluoride and said excess chlorinated or brominated ethylenic compound, wherein the halogenoacetyl in said halogenoacetyl fluoride is selected from the group consisting of chloroacetyls and bromoacetyls; and step 3)—separating said halogenoacetyl fluoride from said excess chlorinated or brominated ethylenic compound.