Polarographic reduction of some acetophenones

Abstract

Summary Measurements are reported on the reduction of a series of ring-substituted acetophenones at a dropping mercury cathode at 25°. An attempt has been made to place the halfwave potentials on a more absolute basis than hitherto, by taking into account the structure of the electrode double layer. The effect of this is to change the slope of the Hammett plot. In addition, a relationship between the reduction process and the ionisation of acetophenones in alkaline media is indicated. The effect of ortho -substituents on the half-wave potential can be interpreted on the different steric requirements of the electrode and ionisation processes, and in the case of the ortho -bromo substituent, the effect becomes sufficiently important to prevent the approach of the second hydrogen in the reduction process.