Immobilization of a Homogeneous RU Catalyst for Hexene and Canola Oil Hydrogenation: Synthesis and Activity

Dichlorodicarbonylbis (triphenylphosphine) ruthenium (II), a cis-selective and homogeneous catalyst, was immobilized on two types of inert solid supports: phosphinated polystyrenes and phosphinated silica gel. In both cases, spacer chains of different length were inserted between the phosphine attachment of the Ru complex and the support surface. Ru attachment efficiencies were determined by neutron activation analysis (NAA). The ability of the heterogenized catalysts to hydrogenate both 1-hexene and canola oil was also tested and the influence of linkage structure on activity was evaluated. In the case of the silica-supported catalysts, Ru dissociated from the support during hydrogenation. In contrast, the polymer-bound Ru remained immobilized during the catalytic reactions. Those polymer catalysts with the shortest linkagechains demonstrated the highest activity in the hydrogenation of 1-hexene. Despite this demonstrated activity, none of the polymer-bound Ru catalysts were active for canola oil hydrogenation.