The electrochemical behaviour of alpha-terpinene, alpha-phellandrene and gamma-terpinene is studied in acetonitrile. Cyclic voltammetry and potentiostatic electrolysis show that the oxidation product is p-cymene and the mechanism is an ECE type, the chemical step being the deprotonation of the cation radical following the first electron transfer. The kinetics of the electrode process are analyzed by means of homogeneous redox catalysis with organic mediators. This leads to the determination of both the standard potential of the terpinene cation radical/parent compound and the deprotonation rate of the corresponding cation radical. (C) 2005 Published by Elsevier B.V.