Competitive hydrogenation/dehalogenation of halogenoarenes with surfactant-stabilized aqueous suspensions of rhodium and palladium colloids:: A major effect of the metal nature

The original palladium colloidal suspensions with an average size of 2.7 nm have been synthesised by reducing Na2PdCl4 with sodium borohydride and were stabilized by water soluble N,N-dimethyl-N-cetyl-N-(2-hydroxyethyl)ammonium chloride salt. The catalytic hydrogenation and dehalogenation of various halogenoarenes have been investigated with this aqueous suspension of palladium nanoparticles and compared with the well-known rhodium suspension. The influences of the halogen fragment and the experimental conditions have also been studied. It was observed that the kinetics and selectivity of the competitive dehalogenation/hydrogenation depend on the nature of metal colloids and the hydrogen pressure. (c) 2006 Elsevier B.V. All rights reserved.