Abstract Electrochemical fluorination of 4-(perfluoro-n-butyl)-n-butanoyl chloride produces perfluorooctanoyl fluoride in higher yields than those obtained from n-octanoyl chloride, which is the usual starting material. In particular, one of the by-products of the industrial process, the cyclic perfluoroether perfluoro-2-propyl-tetrahydropyran, is not formed. Also the other by-products. except fluorocarbon perfluoro-n-heptane, are produced in lower ...