Synthesis of Rhodium polymer-bound catalysts

Abstract

Rhodium polymer-bound catalysts were prepared with three different percent crosslinks. The polymeric supports were formed firstly by suspension polymerization of styrene, divinyl benzene (DVB) and vinylbenzyl chloride. 2-bromoethy1benzene and followed by the dehydrobromination. Several attempts were paid on the generation of the polymeric supports in the spherical form. The type and amount of solvents used in suspension polymerization were experimentally considered in order to obtain the polymeric beads with the largest specific surface area and highest total pore volume. It was found that methylisobutyl carbinol amounted 50% weight by weight of the total monomers was the best solvent. The percentage of crosslinking, DVB, was then varied i.e. 3%, 10% and 20% which afforded the polymeric beads with three different crosslinks. A ligand, anthranilic acid, was subsequently attached to each type of polymeric supports. By variation of several swelling solvents, dimethylformamide was found to be the most appropriate one for anchoring anthranilic acid to the polymeric beads. The treatment of the polymeric supports anchoring anthranilic acid with rhodium trichloride and subsequently with sodium borohydride led to rhodium polymer-bound catalysts. The activities of these rhodium polymer-bound catalysts were monitored by subjection to the hydrogenation of cyclohexene at room temperature.