EVIDENCE FOR THE REVERSIBLE FORMATION OF A CATALYTIC ACTIVE-SITE FOR PROPANE AROMATIZATION FOR GA2O3 H-ZSM-5/

The effects of co-feeding excess hydrogen on the propane aromatization reaction over Ga2O3, H-ZSM-5 and physical mixtures of Ga2O3/H-ZSM-5 a re described and discussed. For Ga2O3 alone co-feeding excess hydrogen gives a significant increase in the conversion and aromatic selectivi ty. For H-ZSM-5 alone co-feeding excess hydrogen gives a slight decrea se in conversion and increases the selectivity to hydrogenated product s. For Ga2O3/H-ZSM-5 physical mixtures co-feeding excess hydrogen lead s to a significant decrease in the conversion and aromatic selectivity . We propose that hydrogen can be used as a reactive probe molecule fo r this reaction. Experiments are also described for propane aromatizat ion over physical mixtures of powdered Ga2O3 and pelleted H-ZSM-5 that provide evidence for the reversible formation of the active site for this reaction.