Catalytic properties of H2-reduced MoO3 and Pt/zeolites for the isomerization of pentane, hexane, and heptane

The catalytic properties of H-2-reduced MoO3 for the isomerization of C-5-C-7 alkanes were compared to those of Pt/HY and Pt/Hbeta zeolites. The pentane isomerization activity decreased in the following order: Pt/Hbeta > H-2-reduced MoO3 > Pt/HY. In contrast, H-2-reduced MoO3 exhibited the lowest activity for heptane isomerization among the catalysts tested. H-2-reduced MoO3 catalyzed the isomerization of heptane more selectively than other catalysts, although no appreciable difference appeared in the selectivity for pentane isomerization. Kinetic parameters on H-2-reduced MoO3 were identical with those on Pt/zeolites, suggesting that isomerization reactions on H-2-reduced MoO3 proceeded via the bifunctional mechanism. We suggested from the results of 2-propanol conversion that the low dehydrogenation-hydrogenation activity of H-2-reduced MoO3 was a reason for its low isomerization activity. Adsorption of heptane was found to be restricted on H-2-reduced MoO3, leading to-the low activity for heptane isomerization. (C) 2002 Elsevier Science B.V All rights reserved.