Electrochemical oxidation of tetrabutylammonium salts of aliphatic carboxylic acids in acetonitrile

The anodic oxidation of a series of tetrabutylammonium aliphatic carboxylates has been performed in acetonitrile on glassy carbon electrodes. The electrochemical behavior was studied without the interference of the anodic oxidation of the solvent. The cyclic voltammetry analysis shows that the electron transfer and the decarboxylation are stepwise. The coulometric analysis shows that the overall mechanism is monoelectronic. However preparative scale electrolysis shows the intervention of two electron-transfer steps leading to carbocations, which then react with the acetonitrile and the carboxylate itself to form N-acylamides as principal products. Two types of adsorption of the carboxylate ions and the alkyl carbocations were proposed to occur selectively, namely, on a small fraction of active sites or on the functional groups existing on the glassy carbon surfaces. (C) 2002 The Electrochemical Society.