Some hydrogen abstractions involving the benzoyloxy radical

The reactivities of triphenylmethane and various penta-arylethanes towards hydrogen abstraction by the benzoyloxy radical are compared. The procedure involved study of the effects of these hydrocarbons upon the yields of carbon dioxide during the decomposition in benzene ofbenzoyl peroxide suitably labelled with carbon-14. Triphenylmethane is less reactive than pentaphenylethane towards the benzoyloxy radical but the reactivity difference is less than might have been predicted from the behaviour of the hydrocarbons with the polystyrene radical. The reactivities of the penta-arylethanes are correlated with the Taft σ^* constants for the substituents.