An efficient route from reproducible glucose to 5-hydroxymethylfurfural catalyzed by porous coordination polymer heterogeneous catalysts

Novel porous coordination polymers (PCPs) modified with sulfonic acid/phosphotungstic acid (PTA) were prepared by hydrothermal method via one-pot self-assembly. The materials were characterized by FTIR, XRD, TEM, SEM-EDS, N2 adsorption/desorption, TG, NH3-TPD, etc., and have been used as solid acid catalysts for reproducible glucose transformation to 5-hydroxymethylfurfural (HMF) in environmentally friendly solvents. With PCP(Cr)-SO3H·Cr(III) as catalyst, over 99.9% glucose conversion and an excellent HMF yield of 80.7% were obtained at 180 °C for 4 h in water, with THF as the online extraction agent for HMF. In this system, the staple glucose material could successfully substitute the expensive fructose (HMF yield = 85.3%). A possible mechanism of glucose conversion and the formation procedure of byproduct were deduced and analyzed. The catalyst could be easily reused with good reproducibility and low wastage of active metal, showing a good prospect for high value applications of glucose.