Acidic hierarchical porous ZSM-5 assembled palladium catalyst: A green substitute to transform primary amides to nitriles

Metal catalyzed dehydration of primary amides is an attractive route for the synthesis of nitriles, but this transformation is often promoted by various environmentally hazardous additives or organic ligands in homogeneous catalysis, which limits its industrial application. The acidic mesoporous ZSM-5 assembled palladium (Pd/ZSM-5-H) was found to be able to systemically convert primary amides to nitriles in the absence of any additives with excellent applicability. The highly dispersive Pd(II) species grafted on ZSM-5-H via the strong binding interaction between AlO4 tetrahedron and Pd species (Pd/ZSM-5-H) drive the significantly higher reaction activity (100%) than Pd/Silicalite-1-H (30%) and Pd(OAc)2 (20%). Furthermore, the active centers of Pd/ZSM-5-H in the catalytic process were attributed to [PdOH]+ by the acidity characterization and theoretical calculations, and the primary amides to nitriles catalyzed by [PdOH]+ in Pd/ZSM-5-H is thermodynamically and kinetically favorable with –OH group in [PdOH]+ as an agent of proton transfer.