Cathodic reduction of acetophenone in acidic methanol. Electrode kinetic study of a novel vicinal diether synthesis

The polarisation curve for the reduction of acetophenone in acidic methanol shows a prewave and a mainwave; the total wave height is diffusion controlled, corresponding to a reaction involving one electron per molecule. The prewave is kinetically controlled, except of course when it contributes a large fraction of the total wave. The products formed at potentials on the shoulder of the prewave are the acetophenone pinacol dimethyl diethers. The mechanism is analogous to that which operates in acetophenone pinacol formation, the reaction which predominates in aqueous media. In the presence of acid, methanol and acetophenone are shown to form the dimethyl ketal; a value for the equilibrium constant is determined.