Patent ID: 6906219

Claim:
A method for preparing compounds of the formula CF 2 BrCO 2 R in which R represents a hydrogen atom, a linear or branched, aliphatic hydrocarbon radical having 1 to 10 carbon atoms or a benzyl radical, said method comprising, in the absence of a catalyst, converting a 1,1-difluoro-1,2-dibromodihaloethane of formula CF 2 BrCBrXY in which X and Y, which are identical or different, represent a bromine atom or a chlorine atom, to bromodifluoroacetyl halide CF 2 BrC(O)Z with Z=Br or Cl, with an oleum having an SO 3 concentration by weight ranging from 50% to 70%, continuously extracting the bromodifluoroacetyl halide from the reaction medium, and directly reacting the bromodifluoroacetyl halide continuously extracted from the reaction medium, either with an alcohol ROH, or with water.