Competitive hydrogenation of benzene and toluene on group VIII metals: correlation with the electronic structure
It has been shown previously that the ratio K/sub T/B/ of the adsorption coefficients of toluene and benzene determined from a kinetic analysis of the competitive hydrogenation of these hydrocarbons can be used to probe the electronic structure of platinum. Because toluene is more of an electron donor than benzene, the larger the electron deficiency of platinum, the larger the K/sub T/B/ values. In the present work the use of competitive hydrogenation has been extended to other Group VIII metals. This was intended to unveil possible relations between the intrinsic electronic structure of these metals (e.g., the density of states in the d-band) and the K/sub T/B/ ratios. The reactions were carried out on Ru, Rh, Pd, Os, Ir, and Pt. Since previous studies have shown that the K/sub T/B/ ratios are sensitive to modifications of the electronic structure induced by the particle environment, these side effects should be kept as low as possible. Accordingly all the catalysts were prepared on silica which is one of the most inert of supports. The particle sizes were essentially in the range 2-5 nm to minimize potential size effects on the electronic structure. It was also checked that the catalysts contain a negligible amount of sulfur, chlorine, and alkali metals liable to induce electron transfer with the metal. 8 references.
- Research Organization:
- Universite Claude Bernard Lyon I, Villeurbanne, France
- OSTI ID:
- 5662459
- Journal Information:
- J. Catal.; (United States), Vol. 102:2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
BENZENE
HYDROGENATION
IRIDIUM
CATALYTIC EFFECTS
ELECTRONIC STRUCTURE
OSMIUM
PALLADIUM
PLATINUM
RHODIUM
RUTHENIUM
TOLUENE
ADSORPTION
CATALYST SUPPORTS
CHEMICAL PREPARATION
COMPETITION
CORRELATIONS
PARTICLE SIZE
SILICA
ALKYLATED AROMATICS
AROMATICS
CHALCOGENIDES
CHEMICAL REACTIONS
ELEMENTS
HYDROCARBONS
METALS
MINERALS
ORGANIC COMPOUNDS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PLATINUM METALS
SILICON COMPOUNDS
SILICON OXIDES
SIZE
SORPTION
SYNTHESIS
TRANSITION ELEMENTS
020400* - Petroleum- Processing
400201 - Chemical & Physicochemical Properties