| Abstract
| - The hydrogenation of 1-butene and 1,3-butadiene has been carried out over a series ofdielectric-oxide-supported nickel catalysts at temperatures ranging from 60 to 120 °C andatmospheric pressure. The catalytic activity and selectivity of these systems were found tobe extremely sensitive to the nature of the support medium, the hydrogen content of thereactant gas mixture, and the reaction temperature. High-resolution transmission electronmicroscopy examinations provided evidence that the active state of the catalyst wasassociated with the partial reduction of the support, particularly in the vicinity of thedispersed metal phase. With some of the dielectric oxides it was essential for the system toremain on stream for prolonged periods of time to achieve the optimum activity. It is proposedthat the induction period is related to the time required to reduce the support to a loweroxide state, which is capable of inducing electronic perturbations in the dispersed metalparticles. It is suggested that the initial role of the metal in this interaction is to functionas a dissociation center for hydrogen, thus providing a source of atomic species for thesubsequent partial reduction of the support. It was significant to find that when nickel wassupported on γ-alumina, an oxide that does not undergo this type of transformation, thecatalytic performance for the respective hydrogenation reactions under these conditions wasextremely poor.
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