Conversions of Mixtures of Propane and Benzene on Pt, Re/Al2O3 + H-Zeolite Systems

The conversion of C6H6 : C3H8C mixtures on mixed catalysts composed of the metal catalysts Pt, ReOx/Al2O3 and zeolites Y, M, and ZSM-5 in the H form was studied. The products of benzene dehydroalkylation by propane and propane dehydrogenation products are formed at 180-350 degrees C. It has been shown that propane is activated on the metal catalysts and C6H6 interacts with the zeolites yielding the C6H7+ intermediate, which acts as an agent of proton transfer from a zeolite to a metal catalyst, and another intermediate C9H13+ (I). Cumene, alkylbenzenes, and propene are formed as a result of the conversion of I. A comparison of the results of the conversion of these mixtures on the composite catalysts with different zeolites shows that the formation of cumene and propene is thermally controlled and the formation of the other products is kinetically controlled. It has been concluded that the coupling of the redox properties of the metal catalysts with the acid-base properties of the zeolite catalysts facilitates the low-temperature transformations of the mixtures.