Synthesis of fluorinated phosphonic, sulfonic, and mixed phosphonic/sulfonic acids

Abstract

The acids (HO)2P(O)CFHSO3H, (HO)2P(O)(CF2)4O(CF2)2SO3H, H(CF2)2O(CF2)2P(O)(OH)2, H(CF2)2O(CF2)4P(O)(OH)2, (HO)2P(O)(CF2)2O(CF2)4H, and the acid precursor (C2H5O)2P(O)CF(SO3Na)2 have been synthesized. Elemental analysis, 19F, 1H, and 31P NMR, and mass spectroscopy were used for characterization of these materials. They are very strong acids, and exhibit a high degree of stability in aqueous solution at elevated temperature, which makes them attractive candidates for use as electrolytes in fuel cells. Keywords: fluorinated phosphonic acids; fluorinated sulfonic acids; 1H, 19F, 31P NMR.