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  • 1 Department of Surface Chemistry and Catalysis, Institute of Isotopes, P. O. Box 77, Budapest 1525, Hungary
  • | 2 School of Chemistry, Molecular Sciences Institute, University of the Witwatersrand Johannesburg, P O WITS, Johannesburg 2050, South Africa
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Abstract

The selectivity obtained in the aromatization of propane over Zn-ZSM-5-based catalysts (Si/Al nominal ratio = 35) increased from about 69% (carbon basis) to 74–91% when a second transition metal ion is introduced into the catalyst. The effect, previously reported for the case of Fe3+ ions, has now been shown to be more general and is seen also for the ions of chromium, cobalt or manganese. It is likely that these ions are present under aromatization conditions in a partially reduced state. H2/D2 isotope exchange rates show large enhancements on the reduced Fe-Zn/ZSM-5 and Co-Zn/ZSM-5 samples. This aspect of aromatization catalysis has not been reported before.

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