Effect of the catalyst preparation method on the performance of Nisupported catalysts for the synthesis of saturated amines from nitrile hydrogenation

SEGOBIA DARIO; TRASARTI ANDRES; APESTEGUIA CARLOS

CHINESE JOURNAL OF CATALYSIS

SCIENCE PRESS

Lugar: Marrickville NSW; Año: 2019 vol. 40 p. 1693 - 1703

0253-9837

The liquid-phase hydrogenation of butyronitrile to saturated amines was studied on silica supported Ni catalysts prepared by either incipient-wetness impregnation (Ni/SiO2-I) or ammonia (Ni/SiO2-A) methods. A Ni/SiO2-Al2O3-I sample was also used. Ni/SiO2-I was a non-acidic catalyst containing large Ni0 particles of low interaction with the support, while Ni/SiO2-A was an acidic catalyst due to the presence of Ni+2 species in Ni phyllosilicates of low reducibility. Ni/SiO2- I formed essentially butylamine (80 %), and dibutylamine as the only byproduct. In contrast, Ni/SiO2-A yielded a mixture of dibutylamine (49 %) and tributylamine (45 %), being the formation of butylamine almost completely suppressed. The selective formation of secondary and tertiary amines on Ni/SiO2-A was explained by considering that butylamine is not release to the liquid phase during the reaction because it is strongly adsorbed on surface acid sites contiguous to Ni0 atoms, thereby favoring the butylimine/butylamine condensation to higher amines between adsorbed species.