Characterization of Nine Isomers in Commercial Samples of Perfluoroethylcyclohexanesulfonate and of Some Minor Components Including PFOS Isomers.

Electrochemical fluorination of 4-ethylbenzenesulfonyl halides produces a mixture of compounds that has found extensive use as an erosion inhibitor in aircraft hydraulic fluids. This paper reports a study of the composition of commercial samples of this material from two industrial scale manufacturers in terms of the structures and relative concentrations of their components, the major of which is perfluoroethylcyclohexanesulfonate (PFECHS). Fractionation of one of these mixtures by column chromatography produced fractions in which all significant components were of sufficient purity to allow assignment of their structures by F NMR spectroscopy.