Mechanism of the cathodic reduction of acetophenone in acidic aqueous-methanolic media

Abstract

The reduction, in acidic aqueous-methanolic media, of acetophenone to its pinacol at several high hydrogen overvoltage metal cathodes follows the simple classical mechanism of reversible addition of a proton and an electron followed by the rate-determining dimerisation of free radicals. Several points are raised concerning recent work which produced apparently quite different results, thereby prompting reconsideration of this system. It is shown that similar results can be obtained if artefacts are not correctly compensated or if electrodes, deactivated with respect to the electron transfer process, are used.