AROMATIZATION OF PROPANE OVER GA/H-ZSM-5 - AN EXPLANATION OF THE SYNERGY OBSERVED BETWEEN GA3+ AND H+

The aromatization of propane is investigated for Ga2O3, H-ZSM-5 and Ga2O3/H-ZSM-5 catalysts, and the results are discussed for a series of ZSM-5 catalysts containing varying SiO2/Al2O3 ratios. It is apparent that on addition of a gallium phase to H-ZSM-5, the yield of methane is significantly decreased. These results are discussed with respect to the mechanism of formation of the initial reaction product from propane. It is proposed that the synergy observed between the gallium compound and the zeolite can be explained in terms of a mechanism in which the role of the gallium phase is to induce C-H bond polarization in the propane, which leads to attack via the Bronsted acid sites of the zeolite, which leads to initial C-H bond cleavage occurring.