Electroreduction and related studies on 2-aminoacrylic acid derivatives. Part II. Electroreactivity of 2-acetamidoacrylic acid

Abstract

Polarographic, cyclic voltammetric, and potentiometric evidence indicates that at low pH values (<4) the mechanism of electroreduction of methyl α-acetamidoacrylate and α-acetamidoacrylic acid involves the protonation of a weak base in a thin layer near the electrode surface. As the protonated form of the substrate is removed by electrolysis, the electroactive substrate is replenished by a chemical reaction between the non-protonated species and a hydrogen ion. With increasing pH, a second wave appears on the polarograms. At high pH values (>4), methyl α-acetamidoacrylate is believed to be reduced in an ECE mechanism, i.e. a reversible charge transfer, followed by an irreversible protonation, followed by an irreversible charge transfer, where the number of electrons transferred in each step is one and ΔE= 0.