OLEFIN METATHESIS OVER SUPPORTED TUNGSTEN CATALYSTS ACTIVATED BY GAMMA-IRRADIATION UNDER A CARBON-MONOXIDE OR METHANE ATMOSPHERE

It is found that supported tungsten-containing catalysts (WO3/SiO2, WO 3/Al2O3) exhibit high catalytic activity in propene and l-hexene metat hesis at 293-423 K after thermal pretreatment in a vacuum and subseque nt gamma-irradiation under a carbon monoxide or methane atmosphere. Sp ecific catalytic activities and productivities of the activated cataly sts in the metathesis reactions are determined. IR-spectroscopic measu rements of adsorbed CO show that gamma-irradiation of the catalysts in the presence of CO or CH4 results in nonselective reduction of W6+ io ns to lower oxidation states. The latter are supposed to be precursors of the active sites for the metathesis reaction. A scheme of processe s occurring under gamma-irradiation is proposed which accounts for the reduction of W6+ ions and the formation of active sites for the metat hesis reaction.