Biphasic Hydrogenation of Olefins by Functionalized Ionic Liquid‐Stabilized Palladium Nanoparticles

Abstract

Palladium nanoparticles in the size range of 5-6 nm were prepared conveniently by reducing palladium(II) with atmospheric pressure hydrogen and stabilized by 2,2'-dipyridylamine-functionalized imidazolium cations according to our approach. The efficient catalytic conversion of cyclohexene into cyclohexane by the functionalized ionic liquid-stabilized palladium nanoparticles has been performed under very mild hydrogen pressure (0.1 MPa) and at 35 8C. It was found that the concentration of palladium and the reaction temperature considerably affected the size and degree of aggregation of Pd nanoparticles in ionic liquid, which further changed the performance of the catalyst activity. The synthesized nanocatalysts can be recycled at least five times without any loss of the activity. Finally, the scope of substrates was also investigated. The excellent catalytic activity of the present system can be attributed to good stabilization and high dispersion of palladium nanoparticles.

Hydrogenation in Ionic Liquids

“…Aggregation of the nanoparticles was observed during the course of the reaction, and a low conversion of only 5 % was reached. Hu et al [98] The stabilized nanoparticles were then used as catalysts for the hydrogenation of cyclohexene, styrene and ethyl acrylate. 100 % yield of reduced product was obtained for each olefin hydrogenation.…”

A Novel Thermoregulated Ionic Liquid and Organic Biphasic System With Rh Nanoparticles for Olefin Hydroformylation

“…Ionic liquids with negligible vapor pressure have been explored as stabilizers for transition-metal nanoparticles. However, in most cases, the reaction systems involving ionic liquids are either monophase allowing for rapid transformation or biphase facilitating separation of product from catalyst [8][9][10][11][12][13]. Therefore, to search for new catalyst systems that might combine the advantages of both homogeneous and heterogeneous catalysis will have a significant impact.…”

Functionalized Poly(ethylene glycol)-Stabilized Palladium Nanoparticles as an Efficient Catalyst for Aerobic Oxidation of Alcohols in Supercritical Carbon Dioxide/Poly(ethylene glycol) Biphasic Solvent System

“…This has resulted in much attention being recently directed toward the development of new protocols for the aerobic oxidation of alcohols using transition-metal catalysts. Among them, palladium-based catalysts show promising catalytic activity, and different types of palladium-based homogeneous [5][6][7] and heterogeneous catalysts [8][9][10] in the form of metal complexes or nanoparticles have been reported.…”