Studies of preparation, characterization, using X-ray diffraction, temperature-programmed reduction and X-ray photoelectron spectroscopy and catalytic properties of several potassium-doped iron-nickel samples were carried out for the hydrogenation of 1,6-hexanedinitrile, in a continuous process at 1 atm pressure, and 443 K. XPS, TPR measurements and catalytic activities detect NiO incipient reduction at 548 K, a NiO reducibility inhibitor character for Fe 3O 4, and surface Ni sinking properties of α-Fe. Total reduction at sample preparation temperatures of 663 K and higher is observed. 100% conversion for a sample reduction temperature of 573 K and various primary amine selectivities depending on sample preparation temperatures are obtained. Active sites for the one-end or two-end-Cn hydrogenations are related to the structural characteristics of the catalysts.