Chemisorption and catalysis by metal clusters. III. Hydrogenation of ethene, carbon monoxide, and carbon dioxide, and hydrogenolysis of ethane catalyzed by supported osmium clusters derived from Os/sub 3/(CO)/sub 12/ and from Os/sub 6/(CO)/sub 18/

Journal Article · Sun Apr 01 04:00:00 EST 1984 · J. Catal.; (United States)

OSTI ID:6732647

Jackson, S D; Moyes, R B; Wells, P B; Whyman, R

Properties are described for catalysts containing high nuclearity metal clusters (nuclearity approx. 12) derived from Os/sub 3/(CO)/sub 12/ and Os/sub 6/(CO)/sub 18/ and supported on silica, alumina, titania, or ceria. Ethene hydrogenation (325-535 K), ethane hydrogenolysis (395-665 K), CO hydrogenation (455-665 K), and CO/sub 2/ hydrogenation (455-715 K) have been examined in pulsed-flow and static reactors. The high nuclearity osmium clusters, protected against sintering by retained ligand-CO, ligand-C, and a support-cluster interaction, are stable under these conditions and provide highly reproducible activity. Freshly prepared catalysts each exhibit an initial non-steady state, during which hydrocarbon is progressively retained and activity rises, passes through a maximum, and declines to a steady state value. Catalysts in the steady state continue to retain hydrocarbon which is probably branched in structure and unsaturated in character. Such retained hydrocarbon species mediate hydrogen atom transfer to reacting adsorbed species. Their concentrations, which have been determined by infrared spectroscopy, /sup 14/C-tracer studies, and material balances, are compared with the known site concentrations associated with fresh cluster-derived catalysts.

• Research Organization: Univ. of Hull, England
• OSTI ID: 6732647
• Journal Information: J. Catal.; (United States), Journal Name: J. Catal.; (United States) Vol. 86:2; ISSN JCTLA
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020500* -- Petroleum-- Products & By-Products
090121 -- Hydrocarbon Fuels-- Chemical Synthesis-- (1976-1989)
10 SYNTHETIC FUELS
ALKANES
ALKENES
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON MONOXIDE
CARBON OXIDES
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTIONS
DECOMPOSITION
ELEMENTS
ETHANE
HYDROCARBONS
HYDROGENATION
HYDROLYSIS
LYSIS
METALS
ORGANIC COMPOUNDS
OSMIUM
OXIDES
OXYGEN COMPOUNDS
PLATINUM METALS
SOLVOLYSIS
TRANSITION ELEMENTS