One-pot catalytic conversion of carbohydrates into furfural and 5-hydroxymethylfurfural

Recently, there has been growing interest in the transformation of renewable biomass into value-added chemicals and biofuels. Among them, furfural and 5-hydroxymethylfurfural (HMF) have received great attention as precursors in the synthesis of a lot of commodity chemicals and liquid fuels. Furfural and HMF can be easily produced from the dehydration of xylose and fructose over acid catalysts, respectively. However, the use of xylose and fructose is limited in large-scale production of furans due to their high cost. Therefore, much effort has been devoted to the synthesis of furfural from xylan and hemicelluloses and HMF from glucose based carbohydrates over different catalysts, particularly with two catalytic sites. Herein, we will provide an overview of the methods developed in recent years to synthesize furfuran and HMF from carbohydrates by using the "one-pot" strategy and discuss major challenges involved in the large scale production of furfural and HMF.