Patent ID: 6949676

Claim:
A process to prepare the fluorosulphonic vinylether CF 2 ═CF—O—CF 2 CF 2 —SO 2 F comprising the following steps: 1) fluorination of the formula (II) compound CH 2 Y—CH(COOR 1 )—O—CF 2 CF 2 CF 2 SO 2F (II) wherein: Y=Cl, Br; R 1 =C 1 -C 4 linear or branched alkyl, to give the acylfluoride CF 2 YCF(COF)OCF 2 CF 2 —SO 2 F; 2) saponification of the acylfluoride to the corresponding carboxylate CF 2 YCF(COO − Me + )OCF 2 CF 2 —SO 2 F, wherein Me + is the alkaline metal cation; 3) thermal decomposition of the carboxylate obtained in 2) and formation of the fluorosulphonic vinylether.