REACTIVITY OF NITROXYL RADICALS IN REACTIONS WITH PHENOLS, AMINES ANDTHIOPHENOLS

Available experimental data on the rate constants of reactions of nitr oxyl radicals with phenols, aromatic amines and thiophenols have been analysed within the framework of a parabolic model of the transient st ate, and the parameters characterizing the reactivity of compounds of each of these groups have been calculated. As regards the activation e nergy of the thermoneutral reaction E-e0, these inhibitors break down in the following sequence (E-e0, J/mole): aromatic amines (38.3), phen ols (45.8), hydroxylamines (45.8), thiophenols (49.3), sterically hind ered phenols (52.5). These parameters have been used to calculate the activation energies and rate constants for 150 reactions with the part icipation of nitroxyl radicals. (C) 1998 Elsevier Science Ltd. All rig hts reserved.