Catalytic Dehydration of Carbohydrates on In Situ Exfoliatable Layered Niobic Acid in an Aqueous System under Microwave Irradiation

Graphical Between the sheets: A simple and efficient microwave-assisted HNb 3 O 8 catalytic process is proposed for the dehydration of carbohydrates in a sustainable pure aqueous system, in which the fast in situ exfoliation of the layered HNb 3 O 8 under microwave irradiation is crucial for the remarkable catalytic performance. A simple and efficient microwave-assisted HNb 3 O 8 catalytic process is proposed for the dehydration of carbohydrates in the aqueous phase. A 5-hydroxymethylfurfural (HMF) yield of 55.9 % was achieved at a high substrate/catalyst weight ratio of 50 from a 10 wt % fructose solution, which is close to the yield achieved by homogeneous aqueous systems. The critical factor for this performance is the fast in situ exfoliation of layered HNb 3 O 8 with the aid of microwave irradiation, which leads to quasi-homogeneous catalytic behavior. Importantly, the catalytic system is also applicable for the one-pot production of HMF from di- and polysaccharides, such as inulin, through a consecutive hydrolysis–dehydration reaction. Additionally, the unique restacking feature of the exfoliated HNb 3 O 8 ensures the good reusability of the catalyst.