FREE-RADICAL COMBINATION REACTIONS INVOLVING PHENOXYL RADICALS

The rates of phenoxyl radical reactions with the superoxide anion radical, O2.-, a peroxyl radical, HOC(CH3)2CH2OO., and an alkyl radical, HOC(CH3)2CH2., in aqueous solution have been measured for 15 different phenoxyl radicals by means of pulse radiolysis. In addition, the one-electron reduction potentials of 10 phenoxyl radicals have been determined. The fraction of electron transfer in the reaction of phenoxyl radicals with O2.-was determined by analysis of gamma-irradiated samples. The experimental data can be accommodated by the Marcus theory for electron transfer, with the reorganization energy lambda-degrees = 155 kJ/mol for the reaction between O2.- and phenoxyl radicals.