CONTRIBUTIONS TO THE ELECTROREDUCTION OF OXIMES

摘要

Shapes of i = f(pH) and E_(1/2) = f(pH) plots indicated that electroreduction at pH lower than about 7 involves a diprotonated form of oxime. This has been supported - in some cases - by the presence of further reduction waves corresponding reduction of the monoprotonated and unprotonated forms. Splitting of the four-electron reduction wave into two two-electron waves has been proven to result from differences in pK_a values of the diprotonated form of the oxime and the protonated form of the imine formed in the first two-electron step. The separation is favored by introduction of an electropositive substituent on aromatic ring in benzaldehyde and acetophenones oximes.