PREPARATION OF ACIDIC OR BIFUNCTIONAL CATALYSTS BY MEANS OF STRAIGHTFORWARD CALCINATION OF AS-SYNTHESIZED [GA]-ZSM-5 ZEOLITES OBTAINED FROM ALKALI-FREE MEDIA - PROPANE AROMATIZATION

Propane aromatization (530-degrees-C, 1 atm) was used as a reaction model to evaluate the effect of the calcination temperature on the catalytic properties of an as-synthesized [Ga1.3]-ZSM-5 zeolite obtained from alkali-free media and calcined at two different temperatures: 530-degrees-C (C-530) and 750-degrees-C (C-750). Results show that in spite of its lower acidity, C-750 is more active and selective toward aromatics than C-530. This is probably due to the fact that at higher temperature the decomposition of organic compounds used during the zeolite synthesis is accompanied by a partial degalliation of the zeolitic support leading to the production of a bifunctional x''Ga2O3''/H-[Ga(y)]-ZSM-5(2x+y=1.3)catalyst.