Studies of the reduction of thionyl chloride in dimethyl formamide using microdisc electrodes

Abstract

The reduction of thionyl chloride (SOCl 2) in dimethyl formamide (DMF) was studied using Pt microdisc electrodes. The total number of electrons involved in this reduction was calculated from the experimental limiting current plateau on the steady-state polarization curves and found to be two. A Tafel plot with a slope very close to 120 mV/decade was also obtained from the steady-state polarization curve of reduction. By analysing the Tafel plot, it is clear that the transfer of the first electron in SOCl 2 reduction is totally irreversible, with α very close to 0.5. Cyclic voltammograms demonstrated that the transfer of the second electron is comparatively rapid, and a product of the two-electron reduction of thionyl chloride, probably sulphur, could be reduced further, to some extent.