Liquid phase hydrogenation of adiponitrile to 6-aminocapronitrile and hexamethylenediamine over potassium doped Ni/α-Al2O3 catalyst

Ni/alpha-Al2O3 and potassium doped Ni/alpha-Al2O3 catalysts with high nickel loading were prepared by the incipient impregnation method and characterized by nitrogen adsorption-desorption, temperature programmed reduction, hydrogen chemisorption, powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy and laser particle size analytical technique. It was revealed that potassium doped Ni/alpha-Al2O3 has smaller nickel crystal size, higher nickel metallic surface area and better nickel dispersion. The prepared catalysts have been tested in the liquid phase hydrogenation of adiponitrile in the absence of ammonia under mild conditions. It has been found that the Ni/alpha-Al2O3 catalyst doped with potassium and reduced under relatively low temperature is favorable for the formation of primary amines. The Ni-K2O/alpha-Al2O3 catalyst exhibits good performance: the selectivity of 6-aminocapronitrile and hexamethylenediamine is 99.7 % at the adiponitrile conversion of 74.1 %.