Kinetic Study of the Oxidation of Catechols in the Presence of N-Methylaniline

The reactions of electrochemically generated o-quinones from oxidation of catechol and 4-methylcatechol as Michael acceptors with N-methylaniline as nucleophile have been studied using cyclic voltammetry. Voltammetric responses show that oxidation of catechols is followed by Michael addition of N-methylaniline. The reaction products are believed to be diphenylamine derivatives of catechols that undergo electron transfer at more negative potentials than the catechols. The observed homogeneous rate constants (kobs) for Michael addition were estimated by digital simulation and show that the reactivity of 4-methyluinone is considerably less than o-quinone. The oxidation potentials of the desired products drastically depend on the solution pH and their structures.