Direct Amination of Biomass‐based Furfuryl Alcohol and 5‐(Aminomethyl)‐2‐furanmethanol with NH 3 over Hydrotalcite‐derived Nickel Catalysts via the Hydrogen‐borrowing Strategy

A series of hydrotalcite‐derived nickel catalysts were synthesized and employed for the direct amination of biomass‐based furfuryl alcohol with NH 3 via the hydrogen borrowing strategy. The effects of the Ni/Al molar ratio and calcination temperature of the NiAl hydrotalcite‐like precursors on the performance of the Ni x Al‐CT catalyst were investigated. The systematic characterization showed that the synergistic catalysis of the metal and acid‐base sites was of vital importance for the amination of alcohols. In particular, the Ni 2 Al‐600 catalyst with high amount of Ni 0 sites (1.26 mmol g −1 ) and suitable density of acid‐base sites (0.71 mmol g −1 and 1.10 mmol g −1 , respectively) exhibited the best dehydrogenation capability and therefore excellent catalytic activity. An 84.1 % yield of furfurylamine with complete conversion of furfuryl alcohol was obtained under the reaction conditions of 180 °C and 0.4 MPa NH 3 in 36 h. The presence of Ni 3 N in the spent catalyst, confirmed by XRD, TEM and XPS characterizations, was demonstrated to be responsible for the deactivation of the Ni x Al‐CT catalyst. In addition, the Ni 2 Al‐600 catalyst exhibited satisfactory performance toward another important biomass‐related transformation of 5‐(aminomethyl)‐2‐furanmethanol to 2,5‐bis(aminomethyl)furan, with a yield of 70.5 %.