Patent ID: 7297815

Claim:
A process for producing a compound represented by the following formula (3a-1), which comprises oxidizing a compound represented by the formula (7-a) by reacting it with chlorine in a solvent comprising water to obtain a compound represented by the following formula (1-a), fluorinating the compound represented by the formula (1-a) to obtain a compound represented by the following formula (1F-a), reacting the compound represented by the formula (1F-a) with fluorine in a liquid phase to obtain a compound represented by the following formula (2-a), and carrying out a decomposition reaction of an ester bond in the compound represented by the formula (2-a): (Y-S) p R C (—CH 2 OCOR—R BF ) q (7-a) (ClSO 2 —) p R C (—CH 2 OCO—R BF ) q (1-a) (FSO 2 —) p R C (—CH 2 OCO—R BF ) q (1F-a) (FSO 2 —) p R CF (—CF 2 OCO—R BF ) q (2-a) (FSO 2 —) p R CF (—COF)) q (3a-1) wherein Y is a hydrogen atom, a monovalent organic group or a —SO 3 − M + group (wherein M is an alkali metal atom), R C is a (p+q)valent organic group having at least two carbon atoms and containing no fluorine atom, R CF is a group having R C perfluorinated and represents a perfluorinated (p+q)valent organic group having at least two carbon atoms, R BF is a perfluorinated monovalent organic group, p is 2 or 3, and q is 1 or 2.