Catalytic deuterium exchange reactions with organics. XXXI. Accelerative effects of ionizing radiation and ultraviolet light on self-activated platinum oxide

Abstract

The effect of preirradiation with γ-rays from cobalt-60 and ultraviolet light from a low-pressure source on the exchange between benzene and heavy water in the presence of self-activated platinum oxide has been studied. Both rates of multiple and stepwise exchange processes are accelerated under these conditions. Of 14 oxides examined, including the Group VIII transition metals, platinum is the only one to catalyse exchange up to 130°. Preliminary experiments indicate that radiation-induced oxygen desorption from the surface of the oxide is responsible for the accelerative effect. Internal radiation sources such as tritium oxide also increase initial exchange rates. Cholesterol, naphthalene, dibenzyl, diphenyl, benzoic acid, and diphenyl ether have been studied with tritium oxide. The results can be rationalized in terms of π- complex mechanisms for exchange. A catalytic model for the mechanism of the radiation-induced effect is proposed.