Mechanism aspects of the hydrogenation of acrylonitrile on Ni and Pd surfaces

Abstract

A combined experimental and theoretical investigation on the hydrogenation of acrylonitrile catalyzed by Ni and Pd is presented. The experiments were conducted in an autoclave and monitored by a computer remote, while the Ni(111) and Pd(111) surface models were employed for theoretical study using density functional theory. Acrylonitrile is preferentially adsorbed on both surfaces through all atoms of the molecular backbone interacting with metal surfaces. For the hydrogenation of the vinyl moiety on Ni, the preferred pathway is initiated by formation of the C1–H bond, while on the Pd surface this step is alternated by making a C2–H bond. Comparison of the reaction pathways for Ni(111) and Pd(111) indicates lower energy barriers for further hydrogenation of the nitrile group on the latter, thus in line with the experimentally observed higher selectivity of the hydrogenation of vinyl catalyzed by Ni.