Synthesis of amines from nitrile hydrogenation on Co/SiO2: Effect of the substrate structure

Abstract

The liquid-phase hydrogenation of aliphatic (acetonitrile, isobutyronitrile and butyronitrile) and (benzonitrile and benzyl cyanide) nitriles was studied on Co(10 %)/SiO2 using ethanol, cyclohexane and toluene as solvents. The catalyst converted the aliphatic nitriles and benzyl cyanide into mainly the primary amine, whereas benzonitrile yielded a mixture of primary and secondary amines. A stronger adsorption of the benzonitrile and benzyl amine over the solid surface promoted the condensation reaction towards the secondary amine. The product distribution was also influenced by the nature of the solvent, particularly in the hydrogenation of aliphatic nitriles, where a stronger solvent-primary amine and solvent-catalyst interaction favored the production of primary amines.