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The title reaction has been investigated at 115{degree}C using HOs{sub 3}(CO){sub 10}(OSi chemical bond) as catalyst or catalyst precursor. By FTIR and XP spectroscopy and by TPDE, evidence exists for the in situ formation of molecular oxidized osmium moieties, covalently anchored to the surface, which are the active catalytic species. The intermediate formation of an olefin adduct during the in situ decomposition of the cluster precursors is supported by chemical extraction of the surface species and further FTIR and {sup 1}H NMR characterization. The reversible poisoning effect of CO and the beneficial influence of H{sub 2} on the catalytic activity and selectivity are also reported and discussed. The catalytic behavior of preformed oxidized osmium surface species has been found to be markedly dependent on the preparation method. The highest activity was obtained when they are formed in situ in the presence of 1-butene. Silica-supported metallic osmium catalysts displayed different activity and selectivity, thus confirming the molecular nature of the catalytic process.

Various forms of Ni-based catalysts have been prepared by different synthetic procedures, affording ordinary f.c.c. Ni metal, a novel h.c.p. Ni allotrope and amorphous NiB powders. The samples were characterized by physical and chemical methods, including XPS, WAXS and SAXS analysis. These techniques provide detailed descriptions of the degree of oxidation of the metal surface and of the physical state of the bulk. The catalytic performance of each catalyst was tested in propene hydrogenation using a flow reactor under mild conditions. Data of intrinsic catalytic activity and activation energy were obtained and are discussed in relation to the morphology and solid state of the samples studied here. The intrinsic catalytic activity of h.c.p. Ni is much higher than that of f.c.c., suggesting the paramount importance of structural features in determining catalytic activity.