PERFLUOROALKYLATION OF OLEFINS BY ELECTROOXIDATION OF PERFLUOROALKANOIC ACIDS - RELATIONS BETWEEN PRODUCT-SELECTIVITY AND CURRENT-DENSITY AND STRUCTURES OF OLEFINS

Electrooxidation of perfluoroalkanoic acids RfCO2H (Rf=CF3, C3F7, C7F15 together with CHF2, CH2F) in the presence of electron-deficient olefins (methyl acrylate, methyl methacrylate, acrylamide, and acrylonitrile) provided perfluoroalkylated products. The electrolysis was conducted in MeCN-H2O (7 : 1) using platinum electrodes in an undivided cell. Dimerization of methyl acrylate accompanying perfluoroalkylation, occurs in 40-50% yield under 20 mA cm-2 current density. 1,2-Addition of trifluoromethyl or difluoromethyl radicals to carbon-carbon double bond predominates in acrylamide under the high current density (100-200 mA cm-2). On the other hand, 1,2-addition of trifluoromethyl and acetamido groups and 1,2-addition of trifluoromethyl and hydroxyl groups occur in the low current density (<5 mA cm-2) electrolysis of methyl methacrylate.