n-octane reforming over alumina-supported Pt, Pt-Sn and Pt-W catalysts

Pt, Pt–Sn and Pt–W supported on γ‐Al2O3 were prepared and characterized by H2 chemisorption, TEM, TPR, test reactions of n‐C8 reforming (500°C), cyclohexane dehydrogenation (315°C) and n‐C5 isomerization (500°C), and TPO of the used catalysts. Pt is completely reduced to Pt0, but only a small fracti...

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Bibliographic Details
Published in:Catalysis letters 2000-01, Vol.64 (2-4), p.171-178
Main Authors: RANGEL, M. C, CARVALHO, L. S, REYES, P, PARERA, J. M, FIGOLI, N. S
Format: Article
Language:English
Subjects:
Aluminum oxide
Bimetals
Catalysis
Catalysts
Catalytic reactions
Chemical activity
Chemisorption
Chemistry
Cyclohexane
Dehydrogenation
Exact sciences and technology
General and physical chemistry
Isomerization
Organic chemistry
Reforming
Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry
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Summary:Pt, Pt–Sn and Pt–W supported on γ‐Al2O3 were prepared and characterized by H2 chemisorption, TEM, TPR, test reactions of n‐C8 reforming (500°C), cyclohexane dehydrogenation (315°C) and n‐C5 isomerization (500°C), and TPO of the used catalysts. Pt is completely reduced to Pt0, but only a small fraction of Sn and of W oxides are reduced to metal. The second element decreases the metallic properties of Pt (H2 chemisorption and dehydrogenation activity) but increases dehydrocyclization and stability. In spite of the large decrease in dehydrogenation activity of Pt in the bimetallics, the metallic function is not the controlling function of the bifunctional mechanisms of dehydrocyclization. Pt–Sn/Al2O3 is the best catalyst with the highest acid to metallic functions ratio (due to its lower metallic activity) presenting a xylenes distribution different from the other catalysts. The acid function of Pt–Sn/Al2O3 is tuned in order to increase isomerization and cyclization and to decrease cracking, as compared to Pt and Pt–W.
ISSN:1011-372X
1572-879X
DOI:10.1023/A:1019082819383