Selectivity of supported and unsupported Pt-H systems in hydrocarbon reactions
Autor: | Pál Tétényi, Zoltán Paál, Helga Zimmer |
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Rok vydání: | 1984 |
Předmět: | |
Zdroj: | Journal of Molecular Catalysis. 25:99-108 |
ISSN: | 0304-5102 |
DOI: | 10.1016/0304-5102(84)80034-6 |
Popis: | The activity and selectivity of the Pt-H system in hydrocarbon reactions was investigated with Pt-black, Pt/Al 2 O 3 and Pt/SiO 2 (Euro Pt 1). The surface concentration of hydrogen was changed by varying the hydrogen pressure while maintaining constant n-heptane reactant pressure. Yields and selectivities of skeletal reactions were determined as functions of the hydrogen pressure. The most dramatic hydrogen effects were observed with Pt-black. Pt/Al 2 O 3 was an aromatizing-cracking catalyst, Pt/SiO 2 an aromatizing-isomerizing catalyst. The effects of carbonization, siliconization and high temperature oxidation-reduction of Pt/SiO 2 were also studied. Adding Si enhanced aromatization, that of C cracking; only slight effects were observed upon oxidation-reduction. The differences between Pt-black and supported catalysts were explained in terms of hydrogen spillover governing the surf ace hydrogen economy. Earlier mechanistic concepts were confirmed; a higher contribution of dehydrogenative C 5 -cyclization to ethylcyclopentane formation was also suggested. |
Databáze: | OpenAIRE |
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