Heterogeneous Catalytic Hydrogenation of 3-Phenylpropionitrile over Palladium on Carbon.

A previously developed and industrially feasible process for selective, Pd-mediated, liquid-phase heterogeneous catalytic hydrogenation of nitriles to primary amines was extended to the reduction of 3-phenylpropionitrile (PPN) to 3-phenylpropylamine (PPA). PPN, which belongs to the homologous series of benzonitrile (BN) and benzyl cyanide (BC), was hydrogenated under mild reaction conditions (30-80 °C, 6 bar), over Pd/C, in two immiscible solvents (dichloromethane/water) and using acidic additives (NaHPO and HSO). Although relatively high conversion (76%) was achieved, the selectivity to PPA (26%) and its isolated yield (20%) were lesser than those in the case of the hydrogenation of BN or BC reported earlier.