Rational regulation of spatially adjacent Al4c and Al6c sites assisted Ru catalysts for low-NH₃ furfural tandem reductive amination

One-pot tandem reductive amination from biomass furfural to furfurylamine requires excessive hazardous NH3 feedstock to improve selectivity, which is not favorable from industrial application and environmental perspective. Herein, we proposed a strategy that utilizing the characteristics of layered double hydroxides to obtain a catalyst which ensures the spatial proximity of four-coordinated Al3+ (Al4c) and six-coordinated Al3+ (Al6c) as complementary functional sites and keep a certain distance with Ru metal sites. The as-synthesized Ru/Ni1MgAlOx catalyst obtained 91.3% yield of furfurylamine under low NH3:furfural ratio of 3:1. The Al4c and Al6c sites were identified to activate NH3 and nitrogenous intermediate respectively, their spatial proximity and appropriate proportion ensured activated intermediate reacting with NH3 preferentially then hydrogenolysis to produce primary amine. This work presented a prospective catalyst for furfurylamine production under low NH3 feeding industrial process and provided a feasible and universal catalyst design strategy for other tandem reactions.(c) 2022 Published by Elsevier Ltd.