Selective electrofluorination of phenylacetonitrile and α-(phenylthio)acetonitrile - The role of sulfur and other operating parameters

Article abstract of DOI:10.1016/S0022-1139(98)00219-X

Cyclic voltammetric and constant current electrolysis were employed to study the electrochemical fluorination of PhCH₂CN and PhSCH₂CN in Et₃N · 3HF/CH₃CN using Pt electrodes. The presence of a sulfur atom near the methylene group in PhSCH₂CN ensures the oxidative fluorination of this compound at much lower potential (around 1.75 V) when compared to PhCH₂CN (2.0 V in solvent-free Et₃N · 3HF). Operating parameters such as drying the solvent, pre-electrolysis, polarity reversal, temperature, current density, and concentration of HF as well as Et₃N in CH₃CN medium show significant influence on the overall yield of more easily oxidisable PhSCH₂CN when compared to PhCH₂CN. Maximum yields of 23% in the case of PhCHFCN and 61% in the case of PhSCHFCN were achieved.