Patent ID: 8030516

Claim:
A method for preparing a perfluoroalkanedi(sulfonyl chloride) having a formula (I) as follows: ClSO 2 CF 2 (CF 2 ) n CF 2 SO 2 Cl (I) the method comprising: a first step of reacting a dibromoperfluoroalkane having a formula (II): BrCF 2 (CF 2 ) n CF 2 Br (II) with SO 2 radical anion or a source of SO 2 radical anion; a second step of reacting the reaction mixture obtained in step one with a halogen selected from a group consisting of chlorine (Cl 2 ), bromine (Br 2 ), and interhalogen compounds consisting of chlorine atom and bromine atom, to form a perfluoroalkanedi(sulfonyl halide) having a formula (III): XSO 2 CF 2 (CF 2 ) n CF 2 SO 2 X′ (III); a third step of reacting the obtained perfluoroalkanedi(sulfonyl halide) with an organic compound to form a perfluoroalkanedi(sulfinate) having a formula (IV): MO 2 SCF 2 (CF 2 ) n CF 2 SO 2 M (IV); and a fourth step of reacting the perfluoroalkanedi(sulfinate) with chlorine (Cl 2 ) to form perfluoroalkanedi(sulfonyl chloride); in which: n is a whole number from one to eight, X and X′ are independently a bromine atom or a chlorine atom, and M is a hydrogen atom, a metal atom, an ammonium moiety, or a phosphonium moiety.