The influence of medium polarity on the kinetics and mechanism of interaction of aliphatic nitroxides with hydroperoxyl radicals

The mechanism of 1,2-substituted ethylene and 1,4-substituted butadiene oxidation with cyclic multiple chain termination by nitroxide radicals has been confirmed using a large set of nitroxides of piperidine, pyrroline, pyrrolidine and imidazoline series. This mechanism includes hydroperoxyl radicals as chain propagating agents and is realized both in non-polar and in polar media. The solvent effect on the rate constant of nitroxide and hydroperoxide radicals interaction is explained by the specific solvation of $${\text{HO}}_{{2}}^{{{ \bullet }}}$$ radicals. An additional effect in high dielectric constant media can be provided by the nonspecific solvation of nitroxide radicals. In low polar solvents the reactivity of > NO• is almost completely determined by > NO–H bond energy of hydroxylamine.