MODIFICATION OF ZEOLITES USING IN-SITU GENERATED ACTIVE SPECIES IN THE GAS-PHASE - I - PREPARATION AND STUDY OF MO-CONTAINING ZEOLITES

A new method of zeolite modification is proposed that is based on the use of active species in the gas phase generated in situ in the course of thermal treatment of mixtures comprising an H-zeolite and a modify ing oxide in an air flow with an admixture of chlorine-containing hydr ocarbons. The use of chemical transport reactions in the case of Mo-co ntaining systems considerably broadens the possibilities of the exchan ge in the solid phase: the formation of reactive and labile molybdenum oxychlorides provides efficient dispersion of the oxide phase with mi gration of Mo5+ ions into the zeolite channels already at 150-200 degr ees C. The peculiarities of introducing paramagnetic Mo5+ ions in zeol ites of different types (ferrierite, ultrastable Y zeolite, Beta zeoli te, ZSM-5 zeolite) are monitored using the ESR method.