Hydrogen isotope exchange in ortho-alkyl-phenyl ketones mediated by illuminated semiconductor powders

Abstract

Photocatalysed hydrogen isotope exchange between o-methylbenzophenone, o-methylacetophenone or 5,8-dimethyl-α-tetralone and deuterium or tritium labelled alcohols has been studied in suspensions containing inorganic semiconductors (CdS. ZnO and TiO₂). It has been shown that adsorption of the ketone onto the semiconductor surface is necessary for the exchange reaction to occur. The influence of the electron scavenger (CBr₄ and O₂) and the hole scavenger (1,3,5-trimethoxybenzene) on the reaction yield has been examined. A mechanism of the studied reaction is proposed.