(EP707094-A1)      Prepn. of perfluoroalkanesulphonyl fluorides (I) comprises electrochemically fluorinating in presence of anhydrous HF a cpd. (II) of formula (RSO2)nX. In (II), R is 1-20C alkyl chain opt. interrupted by one or more O atoms; (a) n is 1, and X is R1, OR2, NR2R3 or SO2R; and R1-R3 are 1-8C alkyl chain opt. interrupted by one or more O atoms or NR2R3 is 5-7 membered ring opt. interrupted by N,O or S; excluding dimethyl sulphone and diethyl sulphone; (b) n is 2, and X is R1, OR1, OR4O or NR2; R1 is 1-8C alkyl chain opt. interrupted by one or more O atoms; and R4 is H or 1-8C alkyl chain opt interrupted by one or more O atoms; or (c) n is 3, and X is R or N. Reaction is conducted under current density of 10-600 amps/sq. m. of anode surface, and a temp. sufficient to maintain boiling HF liq. phase during fluorination.    Also claimed is prepn. of perfluoromethanesulphonyl fluoride (Ia).    USE -   (I) are useful as starting materials for the prepn. of a variety of cpds. having utility as strong acids, herbicides, pesticides, antimicrobials, pharmaceuticals, and as electrolyte from battery or fuel cell applications.    ADVANTAGE -   (I) can be prepd. in good yield. Process is more electrically-efficient and more fluorine-efficient than conventional preparative methods.    (JP8176096-A)      Prepn. of perfluoroalkanesulphonyl fluorides (I) comprises electrochemically fluorinating in presence of anhydrous HF a cpd. (II) of formula (RSO2)nX. In (II), R is 1-20C alkyl chain opt. interrupted by one or more O atoms; (a) n is 1, and X is R1, OR2, NR2R3 or SO2R; and R1-R3 are 1-8C alkyl chain opt. interrupted by one or more O atoms or NR2R3 is 5-7 membered ring opt. interrupted by N,O or S; excluding dimethyl sulphone and diethyl sulphone; (b) n is 2, and X is R1, OR1, OR4O or NR2; R1 is 1-8C alkyl chain opt. interrupted by one or more O atoms; and R4 is H or 1-8C alkyl chain opt interrupted by one or more O atoms; or (c) n is 3, and X is R or N. Reaction is conducted under current density of 10-600 amps/sq. m. of anode surface, and a temp. sufficient to maintain boiling HF liq. phase during fluorination.    Also claimed is prepn. of perfluoromethanesulphonyl fluoride (Ia).    USE -   (I) are useful as starting materials for the prepn. of a variety of cpds. having utility as strong acids, herbicides, pesticides, antimicrobials, pharmaceuticals, and as electrolyte from battery or fuel cell applications.    ADVANTAGE -   (I) can be prepd. in good yield. Process is more electrically-efficient and more fluorine-efficient than conventional preparative methods.    (EP707094-B1)      Prepn. of perfluoroalkanesulphonyl fluorides (I) comprises electrochemically fluorinating in presence of anhydrous HF a cpd. (II) of formula (RSO2)nX. In (II), R is 1-20C alkyl chain opt. interrupted by one or more O atoms; (a) n is 1, and X is R1, OR2, NR2R3 or SO2R; and R1-R3 are 1-8C alkyl chain opt. interrupted by one or more O atoms or NR2R3 is 5-7 membered ring opt. interrupted by N,O or S; excluding dimethyl sulphone and diethyl sulphone; (b) n is 2, and X is R1, OR1, OR4O or NR2; R1 is 1-8C alkyl chain opt. interrupted by one or more O atoms; and R4 is H or 1-8C alkyl chain opt interrupted by one or more O atoms; or (c) n is 3, and X is R or N. Reaction is conducted under current density of 10-600 amps/sq. m. of anode surface, and a temp. sufficient to maintain boiling HF liq. phase during fluorination.    Also claimed is prepn. of perfluoromethanesulphonyl fluoride (Ia).    USE -   (I) are useful as starting materials for the prepn. of a variety of cpds. having utility as strong acids, herbicides, pesticides, antimicrobials, pharmaceuticals, and as electrolyte from battery or fuel cell applications.    ADVANTAGE -   (I) can be prepd. in good yield. Process is more electrically-efficient and more fluorine-efficient than conventional preparative methods.