Hydrogenation of olefins by polymer-bound palladium(II) Schiff base catalyst

Chloromethylated poly(styrene-divinylbenzene) was modified into coordinating Schiff base bearing ligand which was subsequently complexed with palladium chloride and activated by using sodium borohydride. The polymer-supported palladium complex and activated catalyst were characterized by various techniques such as elemental analysis, X-ray photoelectron spectroscopy, atomic absorption spectroscopy, IR, far IR spectral studies, SEM and thermogravimetric analysis. Surface area measurements by BET method and swelling studies with different solvents for the catalyst were also carried out. Catalytic activity towards hydrogenation of 1-hexene, 1-heptene, 1-octene, cyclohexene, norbornadiene (nbd) and 1,5-cyclooctadiene (1,5-cod) was assessed. The influence of variation in temperature, pressure, concentration of the catalyst as well as the substrate and the nature of the solvent on the rate of the reaction was studied for a few olefins. Recycling ability of the catalyst was also evaluated.

Graphical abstractA palladium catalyst was synthesized by modifying chloromethylated poly(styrene-divinylbenzene) into a coordinating Schiff base ligand which was complexed with palladium chloride. The activity of the catalyst was investigated towards hydrogenation of olefins under ambient conditions of temperature and pressure. The polymer-bound catalyst was found to be superior to its homogeneous counter part in its stability and reusability.Figure optionsDownload full-size imageDownload as PowerPoint slide