Palladium nanoparticles in polyethylene glycols: Efficient and recyclable catalyst system for hydrogenation of olefins

Hydrogenation of olefins catalyzed by palladium nanoparticles dispersed in polyethylene glycols (PEGs) was carried out. It was shown that Pd nanoparticles in PEG800 (PEG with an average molecular weight of 800 g/mol), PEG1000, and PEG2000 were very active, stable, and selective for hydrogenation of a range of olefins at mild conditions. For simple alkenes like cyclohexene, the pure products were isolated by simple decantation because the miscibility of the products and the PEGs was extremely poor. For olefins with polar groups, the CC double bonds were selectively hydrogenated with 100% selectivity. The reusability of Pd-PEG2000 was tested, and deactivation of the catalyst was not detectable after 10 recycles.