Selective hydrogenation of acetonitrile to ethylamine using palladium-based alloy catalysts

Abstract

Gas phase hydrogenation of acetonitrile has been studied with various Pd-based catalysts using several supports, ZrO₂, CeO₂, MgO, SiO₂, Al₂O₃, ZnO, Ga₂O₃ and In₂O₃. The catalysts may be divided into two groups, one of which includes ZnO, Ga₂O₃, and In₂O₃-supported catalysts and another group includes the other catalysts. The catalysts of the former group are less active but selective to the formation of ethylamine (MEA) and diethylamine (DEA). In particular, MEA is preferentially produced with the Pd/ZnO catalyst. These catalytic features may be ascribed to the formation of such Pd alloys as PdZn, Ga₅Pd, Ga₂Pd₅, and In_0.52Pd_0.48 as confirmed by X-ray diffraction. Compared with these Pd alloy catalysts, the other catalysts including metallic Pd only are more active but less selective to MEA and DEA, similar to Pd black. The activity of Pd alloy catalysts can be improved by preparing the alloys on the surface of CeO₂ support while maintaining their higher selectivity to MEA and DEA.