Palladium-nanoparticles catalyzed hydrodehalogenation of aryl chlorides in ionic liquids

Pd-nanoparticles, in molten tetrabutylammonium bromide as the solvent and tetrabutylammonium acetate as the base, catalyze the hydrodehalogenation of various aryl chlorides under hydrogen at atmospheric pressure. Recycling experiments show a decreasing activity of this catalyst due to a small leaching of palladium from the ionic liquid phase during the extraction of the reaction products with cyclohexane. On the contrary, leaching is avoided when vacuum distillation is used to separate the dehalogenated products form the reaction mixture, thus allowing an extensive recycling of the Pd-catalyst.