Hydrogenation of Nitrile Butadiene Rubber Catalyzed by [Ir(COD)py(PCy3)]PF6

The application of [Ir(COD)(PCy3)(py)]PF6, ((COD) 1,4 cyclooctadiene, (PCy3) tricyclohexylphosphine, (py) pyridine) “Crabtree’s catalyst” 1 for the hydrogenation of nitrile butadiene rubber (NBR) has been investigated for the first time. The catalyst was efficient for selective hydrogenation of olefinic groups in NBR. A preliminary kinetic study was used to explore the possible catalytic pathway. The process was found to be first order with respect to [Ir] at relatively low hydrogen pressures. As pressure was increased the process showed first to zero order behavior with respect to [Ir], implying that at low [Ir] the active complex is mononuclear, but as hydrogen pressure is increased dimerization to a less active binuclear species may occur.