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

Propane aromatization (530-degrees-C, 1 atm) was used as a reaction mo del to evaluate the effect of the calcination temperature on the catal ytic properties of an as-synthesized [Ga1.3]-ZSM-5 zeolite obtained fr om alkali-free media and calcined at two different temperatures: 530-d egrees-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 aroma tics than C-530. This is probably due to the fact that at higher tempe rature the decomposition of organic compounds used during the zeolite synthesis is accompanied by a partial degalliation of the zeolitic sup port leading to the production of a bifunctional x''Ga2O3''/H-[Ga(y)]- ZSM-5(2x+y=1.3)catalyst.