Polystyrene-based catalysts with simultaneous Brønsted and Lewis acidity for hydroxymethylfurfural production from starch: molecular weight and solvent effects

Biomass-derived chemicals, such as hydroxymethylfurfural (HMF), have the potential to supplement other petroleum-derived products. Several catalysts have been reported in the literature for producing HMF from fructose, glucose, and starch; however, challenges like low catalyst activity, deactivation, or difficult recovery have been encountered. Here, we report a series of polystyrene-based catalysts with simultaneous Brønsted and Lewis acidity and the advantages of both homogeneous and heterogeneous catalysis: soluble in water and easy to recover and reuse. For the first time, we show that these novel catalysts can be prepared under atmospheric conditions without the need for an inert atmosphere or costly anhydrous solvents, which is an advantage from an environmental and economic point of view. Additionally, we report that these catalysts can carry out the one-pot synthesis of HMF from potato starch, which involves the hydrolysis of starch, isomerization of glucose to fructose, and dehydration of fructose to HMF.