The effect of surface acidic and basic properties on the hydrogenation of lauronitrile over the supported nickel catalysts

摘要

Supported nickel catalysts with different supports (MgO, SiO2, A12O3, MgAlO and SiAlO) were prepared by the co-precipitation method and dried in n-butanol. Nickel was found to be relatively easier to reduce in Ni/MgO and Ni/SiO2 than in Ni/Al2O3, while nickel was higher dispersed in Ni/SiO2 than in Ni/Al2C>3 and Ni/MgO. Thus, the reducibility and dispersion of nickel in Ni/MgAlO and Ni/SiAlO were significantly enhanced, leading to the high active nickel surface areas (75 m~2/g-catalyst). Acetonitrile was found to be adsorbed on the reduced nickel and acidic sites. The strong surface basicity of Ni/MgO was found to favor the selectivity to the primary amine, but inhibited the conversion of lauronitrile. On the other hand, the conversion of lauronitrile was high over the Ni/SiO2, Ni/Al2O3 and Ni/SiAlO with strong surface acidity, but the selectivity to the prime amine was relatively low. The Ni/MgAlO with intermediate strengths of surface acidity and basicity exhibited the high conversion of lauronitrile and high selectivity to the prime amine.