Efficient 5-hydroxymethylfurfural synthesis from carbohydrates and food wastes in aqueous-natural deep eutectic solvent (A-NADES) with robust Al2O3 or Al(OH)3

As one of the essential building blocks for bio-chemicals and bio-fuels, the 5-Hydroxymethylfurfural (HMF) production is still challenging in a green and cheap way. This work developed a bio-derived aqueous-natural deep eutectic solvent (A-NADES) to synthesize HMF using α-Al 2 O 3 or Al(OH) 3 as robust catalysts, obtaining high yields of 67.1% and 63.6% HMF from glucose under mild reaction reactions, respectively. Different kinds of starches and starchy food waste also exhibited high conversion efficiency in the A-NADES system. The mechanistic study indicated that the in-situ formed Al (III) site of α-Al 2 O 3 during the reaction was critical for converting glucose-based carbohydrates. A-NADES could be effectively reused six times with a more convenient direct reuse method without significant activity loss. This study suggested a novel A-NADES reaction media in the synergistic reaction with robust aluminum-based catalysts for HMF synthesis, and proposed a novel process of food waste utilization in green solvents.