Electrochemical oxidation of 3-methylpyridine at a boron-doped diamond electrode: application to electroorganic synthesis and wastewater treatment

The electrochemical oxidation of 3-methylpyridine (3-MP) at synthetic boron-doped diamond (BDD) thin film electrode has been studied in acid media by cyclic voltammetry and bulk electrolysis. The results have shown that in the potential region of water stability there can occur direct electron transfer reactions on BDD surface that result in electrode fouling due to the formation of a polymeric film on its surface. While during electrolyses in the potential region of water decomposition, indirect oxidation reactions can take place by electrogenerated active intermediates, probably hydroxyl radicals that can avoid electrode fouling. Depending on the values of applied current density, it is possible to obtain the partial oxidation of 3-MP to nicotinic acid or the complete combustion of 3-MP to CO2. (C) 2001 Elsevier Science B.V. All rights reserved.