Abstract

The effect of different supports (SiO2, Al2O3, TiO2, and ZrO2) on nickel phosphide as an active phase in the reductive amination reaction (using aniline and octylamine) for the synthesis of 5-methyl-N-alkyl-2-pyrrolidone was studied. The experiments were conducted at 200 degrees C and 50 bar H-2, using dioxane as the reactive solvent. Various techniques were employed to characterize the catalysts, including N-2 adsorption-desorption, H-2-temperature-programmed reduction (H-2-TPR), X-ray diffraction (XRD), pyridine-FTIR, and X-ray photoelectron spectroscopy (XPS). Firstly, the supports influenced the nickel species present on the surface and the number of acidic sites in each catalyst. Secondly, in the reaction between levulinic acid and aniline, the turnover frequency (TOFM2 -> 5MPanilina ) for 5-methyl-1-phenyl-2-pyrrolidone production followed the order: NiP/Al2O3 > NiP/ZrO2> NiP/SiO2> NiP/TiO2. Regarding the reaction between levulinic acid and 1-octylamine, the TOFL1 -> 5MPoctylamine for 5-methyl-N-octyl-2-pyrrolidone production followed the order: NiP/ZrO2> NiP/Al2O3 > NiP/SiO2> NiP/TiO2. Finally, the supports influenced the type of nickel phosphide species present on the catalyst surface and, consequently, the hydrogenation rate to pyrrolidone molecules.