A Comprehensive Study on the Reductive Amination of 5-Hydroxymethylfurfural into 2,5-Bisaminomethylfuran over Raney Ni Through DFT Calculations

Graphical Raney to the rescue ! High value-added 2,5-bisaminomethylfuran was one-pot synthesized from 5-HMF over Raney Ni with a yield of 60.7 %. DFT calculations were conducted to support our speculation that Ni can harmonize NH 3 and H 2 on its surface most suitably for the reductive amination reactions. Reductive amination of furfuryl alcohol, furfural and 5-hydroxymethylfurfural (5-HMF) were carried out on various metal catalysts. Over Raney Ni catalyst, we obtained the highest furfurylamine yields of 81.8 % and 94.0 % from furfuryl alcohol in absence and presence of H 2 , respectively. While furfural was used as the substrate, 100 % yield of furfurylamine could be achieved over Raney Ni under rather moderate conditions. Although 5-HMF was completely converted over all catalysts used, the highest yield of 2,5-bisaminomethylfuran (60.7 %) was obtained over Raney Ni at 160 °C in 12 h. The DFT calculations on the adsorption behavior of NH 3 and H 2 on different metal surfaces showed that the difference of the adsorption energy between NH 3 and H 2 on Ni is lower than those of other metals, indicating that less metal active sites on Ni surface is occupied by NH 3 , which leaves more active sites for dehydrogenation/hydrogenation reactions and in the end promotes the reductive amination reactions.