Study of autoxidation by spin trapping. Spin trapping of peroxyl radicals by phenyl N-t-butyl nitrone

Abstract

The autoxidation of several organic compounds has been studied by the spin trapping technique. The chaincarrying peroxyl radicals were trapped by phenyl N-t-butyl nitrone (PBN) under the conditions of oxidation and hyperfine splitting constants were measured for several peroxyl radicals. Peroxyl radicals generated from other sources such as induced decomposition of hydroperoxides and thermal decomposition of azo-compounds under oxygen also gave similar results. The rate constants for the reaction of cumyl- and tetralinyl-peroxyl radicals with PBN were found to be much lower than those for the reactions of corresponding alkyl radicals with PBN. The hyperfine splitting constants of the spin adduct obtained in the oxidation of propan-2-ol in the presence of PBN were found to agree well with those observed in the oxidation of cyclohexa-1.4-diene, suggesting that the chain-carrying radical in the oxidation of propan-2-ol is not 1 -hydroxy-1 -methylethylperoxyl radical but hydroperoxyl radical.