Efficient production of 5-hydroxymethylfurfural from glucose over silica-tin oxide composite catalysts

In this study, silica-tin oxide composites (xSiSnO) and a H 3 PO 4 modified 20SiSnO (SiSnPO) have been synthesized via a simple procedure and evaluated for the catalytic dehydration of glucose to 5-hydroxymethylfurfural (HMF). FTIR, XPS, UV–vis, NH 3 -TPD, and Py-FTIR characterizations revealed that Sn species were possibly inserted into the framework structure of silica to generate weak-to-medium Lewis acid sites; besides, calcining H 3 PO 4 impregnated 20SiSnO obviously improved the Brønsted acid sites. When the 20SiSnO/HCl combined catalysts were used, a high HMF yield of 75.5% was achieved in DMSO/H 2 O at 160 °C for 60 min, and the 20SiSnO showed relatively high stability even under thermal acidic environment. By utilizing the multifunctional SiSnPO as catalyst, an inspiringly high HMF yield was also reached (70.3%), and the SiSnPO exhibited reasonable recyclability for glucose dehydration. Furthermore, the possible reaction pathway of glucose dehydration over SiSnPO catalyst has been discussed.