Palladium Nanoparticles Suspended in an Ionic Liquid as Reusable Catalyst for Alkyne Semihydrogenation

The reaction of PdCl 2 dispersed in tetra-n-butylammonium bromide with tributyl amine at 120 °C under argon leads to stable isolable nanometric particles. X-ray diffraction analysis of the material indicated that it is constituted of Pd(0). Transmission electron microscopy analysis of the particles dispersed in acetone shows the mean particle size distribution (4 ± 1 nm). The isolated palladium nanoparticles can be dispersed in an ionic liquid or in methanol or used in solventless condition for selective hydrogenation of 2-hexyne under mild reaction conditions(0.2 MPa and 20 °C). The commercial variety of the Lindlar catalyst was also studied for comparative investigations.