Reactivity of substituted phenols toward alkyl radicals

The kinetics of hydrogen atom transfer from substituted phenols to primary alkyl radicals were studied. It was established that hydrogen atom shift from a phenolic antioxidant resulted in a hydroperoxide and an aryloxyl radical. It was observed that the rate constants for the hydrogen atom abstraction from 18 phenols were greater in phenols having electron-donating para substituents and lesser in phenols substituted with electron-withdrawing groups.