Patent ID: 7157600

Claim:
A process for preparing (per)fluorohalogenethers containing the —SO 2 F group and having general formula (I): FSO 2 —R—CF 2 OCAF—CA′F 2 (I) wherein: A and A′, equal to or different from each other, are Cl or Br; R has the following meanings: a (per)fluorinated substituent, selected from the following groups: linear or branched C 1 –C 20 alkyl, C 3 –C 7 cycloalkyl; aromatic, C 6 –C 10 arylalkyl or alkylaryl; C 5 –C 10 heterocyclic or alkylhetero-cyclic; optionally containing one or more oxygen atoms; when R is fluorinated, it can optionally contain one or more H atoms and/or one or more halogen atoms different from F; by reaction of carbonyl compounds having formula (II): FSO 2 —R—COF (II) wherein R is as above; in liquid phase with elemental fluorine and with olefinic compounds having formula (III): CAF═CA′F (III) wherein A and A′ are as above, by operating at temperatures from −120° C. to −20° C., optionally in the presence of a solvent inert under the reaction conditions.