NEW MATERIAL:A compound of formulaI[Rf is 1W20C perfluoroalkyl; X is -OSO2Y (Y is alkyl, aryl), halogen, OM (M is H, alkali metal atom, ammonium residue), alkoxy, -OCOZ (Z is alkyl, aryl), halogen, BF4, ClO4, SbF4; n is 0, 1].

EXAMPLE: N-[4-(n-Heptadecafluorooctyl)-2-butenyl]pyridinium trifluoromethanesulfonate.

USE: Synthetic intermediate of chemicals such as surface active agents.

PREPARATION: Pyridine, a compound of formula II and another compound of formula III are made to react at -30W100°C to give the compound of formula I. In the reaction a solvent such as methylene chloride, DMSO, THF or the like may be used.