Neopentane reactions over bimetallic Pt-Sn/Al sub 2 O sub 3 and Pt-Au/SiO sub 2 catalysts
- Univ. of Michigan, Ann Arbor (United States)
The reaction of 2,2-dimethylpropane (neopentane) with hydrogen was studied over two series of supported bimetallic catalysts containing platinum as the primary group VII metal and either gold or tin as the second metallic component. In both catalyst series the platinum nominal loading was maintained constant at 1 wt%. The loading of the second metal component was varied. An effort has been made to better understand the reactivity trends in these catalysts, by bringing the neopentane reactivity data into context with previously obtained n-hexane reaction results and extensive catalyst characterization data. Small amounts of tin (1.0 Pt-0.1 Sn/Al{sub 2}O{sub 3}) caused the neopentane isomerization selectivity to drop in comparison to monometallic 1.0 Pt/Al{sub 2}O{sub 3}. However, further addition of tin up to 1.0 wt% caused the neopentane isomerization selectivity to increase above that of the monometallic 1.0 Pt/Al{sub 2}O{sub 3} sample. On adding excess tin (5.0 wt%) the activity of the catalyst became prohibitively low. Hence, there seemed to be an optimum loading of tin giving desirable selectivity characteristics at reasonable activity levels. The differences in isomerization selectivity in the case of the Pt-Au/SiO{sub 2} catalysts were not as significant as those observed for the Pt-Sn/Al{sub 2}O{sub 3} catalysts. The trends in catalytic behavior were consistent with previously measured n-hexane reaction trend and could be interpreted on the basis of microstructural differences between the bimetallic catalysts. The effect of gold appeared to be mainly a geometric one, disrupting larger Pt ensembles. On the other hand, the role of tin appeared to go beyond a simple geometric effect.
- OSTI ID:
- 6984560
- Journal Information:
- Journal of Catalysis; (United States), Journal Name: Journal of Catalysis; (United States) Vol. 132:2; ISSN 0021-9517; ISSN JCTLA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
020400* -- Petroleum-- Processing
2-2-DIMETHYLPROPANE
ALKANES
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
BIMETALS
CATALYST SUPPORTS
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTIONS
COMPARATIVE EVALUATIONS
CRYSTAL STRUCTURE
ELEMENTS
EVALUATION
GOLD
HEXANE
HYDROCARBONS
HYDROGENATION
ISOMERIZATION
METALS
MICROSTRUCTURE
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PLATINUM
PLATINUM METALS
TIN
TRANSITION ELEMENTS