HETEROGENEOUS CATALYSIS IN SUSTAINABLE GREEN SOLVENT: ALKENES HYDROGENATION WITH NEW SILICA IMMOBILIZED PALLADIUM COMPLEX CONTAINING S,O-CHELATING LIGAND

Abstract

Pd(II) complex containing S,O-chelating ligand was immobilized on surface of the amine functionalized silica support in scCO2 media. Silica-based catalyst (SiO2-ThiophPd(II)) were characterized by IR, SEM, XRF, and BET analyses. The catalytic activity of the immobilized catalyst in hydrogenation reactions of alkenes has been compared with the homogeneous counterpart. SiO2-ThiophPd(II) catalyst showed good activity and reusability than homogeneous system. The best conversion in styrene hydrogenation was obtained with TOF value as 5871 h-1 at 370 K, 10 bar H2 and 1500 psi total pressure. Especially, while homogeneous counterpart has not activity in cyclohexene hydrogenation, it has been provided 100% cyclohexane conversion with the immobilized catalyst. It has also been found that the catalyst can be reused at least ten times without significant loss of activity in the styrene hydrogenation