Reductive amination of isopropanol to monoisopropylamine over Ni-Fe/gamma-Al2O3 catalysts: Synergetic effect of Ni-Fe alloy formation

Abstract

We herein reported the syntheses of 17 wt% Ni-xFe/gamma-Al2O3 catalysts containing different Fe/Ni molar ratios (x = 0-0.7) via an incipient wetness impregnation method, followed by subsequent investigation of their catalytic properties in the reductive amination of isopropanol (IPA). We attempted to reveal the synergetic effect of bimetallic Ni-Fe on gamma-Al2O3 support through characterization of the catalysts by N-2-sorption, X-ray diffraction, H-2-temperature-programmed reduction, and X-ray photoelectron spectroscopy. We found that conversion and selectivity to monoisopropylamine (MIPA) through the reductive amination of IPA was influenced by the reducibility of the catalysts. In addition, the surface Ni-o content increased upon the addition of Fe species, with a maximum Ni-o content being reached at a Fe/Ni molar ratio of 0.3. This molar ratio also yielded the highest conversion and MIPA selectivity, and no deactivation was observed for 100 h on stream in the presence of hydrogen gas. In addition, reaction parameters, such as the partial pressures of H-2 and NH3, the space velocity, and the reaction temperature were also examined to optimize the experimental conditions.