Studies on deiodo-sulfination Part. II. The reactions of perfluoroalkanesulfinates with halogen and halogen acids and a new method for the synthesis of perfluorosulfonic acid

Abstract

Abstract In the presence of a small amount of hydroquinone, reaction of potassium 3-oxaoctafluoropentane-1,5-disulfinate ( I ), 5-iodo-3-oxa- octafluoropentanesulfinate ( VII ) or 7-iodo-3-oxa-dodecafluoroheptanesulfinate ( XII ) with hydriodic acid gives the corresponding perfluorocarboxylic acid 3-oxahexafluoropentanedioic acid ( II ), 5-iodo- 3-oxahexafluoropentanoic acid ( III ) or 7-iodo-3-oxadecafluoroheptanoic acid ( XIII ), respectively. The formation of 1,5-diiodo-3-oxaoctafluoropentane ( IV ) or 1,5-dibromo-3-oxaoctafluoropentane ( VIII ) from the reaction of I or VII with I2 or Br2, respectively, has not been previously recorded in the literature. In the case of iodine this can be regarded as a retro-deiodo-sulfination. However, the reaction of the sulfinate with C12 stops at the sulfonyl chloride stage. Deiodo-sulfination provides a new method for the synthesis of perfluorocarboxylic acids, perfluoroalkyl bromide and perfluorosulfonic acid from RFI.