Reduction mechanism of deoxybenzoin on a mercury electrode

The electrochemical reduction of deoxybenzoin at the HDME has been studied as a function of pH. Electrodimerization occurs in strongly acidic and basic media which gives rise to either the neutral or the dianionic forms of the dimer, respectively. In the 7.5–9.5 pH range, an alcohol is formed by a two-electron, two-proton irreversible charge transfer. It is shown that transitions between these three simple cases occur through kinetically controlled protonation steps. A chronoamperometric analysis has been implemented to estimate the kinetics of the surface protonation that precedes the electron transfer step in the 4–7 pH range. Digital simulation has been used to characterize the competitive processes that lead to either the alcohol or the dianionic dimer in the 9.5–12 pH range.