AROMATIZATION OF PROPANE OVER MFI-GALLOSILICATES

The results of propane aromatization over gallium containing HZSM-5 zeolites are described. Highly dispersed gallium in the zeolite (framework or extra-framework) was found to possess dehydrogenation activity, especially in the presence of strong Bronsted acid sites. The extra-framework gallium was introduced by mildly steaming a H-(Ga)ZSM-5 zeolite or by physically mixing Ga2O3 or a GAPSO-11 molecular sieve with H-(Al)ZSM-5. The higher dehydrogenation rates in the presence of gallium facilitated the formation of carbonaceous products, resulting in higher deactivation rates. A mechanism for hydrogen formation is discussed.