DEHYDROALKYLATION OF BENZENE WITH PROPANE ON MECHANICAL MIXTURES OF CATALYSTS

Abstract

The conversion of C6H6 : C3H8 mixtures on mixed catalysts (MMC) composed of the metal oxide catalysts M,ReOx/Al2O3 (Pt or Ni -0.5 wt.%, Re-1.0 wt.%) and zeolites Y, МOR, and ZSM-5 in the H form was studied. The products of benzene dehydroalkylation by propane and propane dehydrogenation products are formed at 200–400°C. It has been shown that C3H8 is activated on the metal oxide 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+ . Cumene, alkylbenzenes, and propene are formed as a result of the conversion . Acomparison 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 oxide catalysts with the acid–base properties of the zeolite catalysts facilitates the low–temperature transformations of the C6H6 : C3H8 mixtures. Keywords: dehydroalkylation, dehydrogenation, benzene, propane, mechanical mixture of catalysts, zeolite isopropylbenzene, propylene