Process for the preparation of compounds containing perfluoroalkanesulfonic acid groups

A compound of the formula

• Mn+[OSO2CF3]n−,
• type, in which Mn+ is a ring of the formula:
• where
• n is 1 or 2,
• X and Y are P or N, and
• R1,R2
• and R3 identical or different and are each, individually or together,
• hydrogen,
• an alkyl group having from 1 to 16 carbon atoms,
• an alkylaryl group whose alkylene group has from 1 to 16 carbon atoms,
• an aryl group or
• a heterocyclic group,
• where one, two or three CH2 groups in the ring and/or the alkyl groups may be replaced by identical or different heteroatoms, and
• where the ring and/or the alkyl group may be partially substituted, and
• where the alkylaryl group, the aryl group and/or the heterocyclic group may be partially substituted.