Preparation of 5-hydroxymethylfurfural from cellulose catalyzed by silicon-based composite solid acids

In order to improve the efficiency of solid acid catalyzed cellulose preparation of 5-hydroxymethylfurfural (HMF), this study prepared a silica-based solid acid with dual acid sites comprising both Lewis and Brønsted acids. Firstly, SiO₂ microspheres prepared by reverse microemulsion method were used as the carrier, and the surface was modified with –SO₃H and –NH₂, and finally Cr³⁺ was loaded on to SiO₂ to prepare the composite solid acid catalyst Cr-SiO₂–SO₃H, and its characterization and catalytic performance were determined. The experimental results showed that in the two-phase reaction system composed of [BMIM]Cl and THF, using microcrystalline cellulose (MCC) as the substrate, when the reaction temperature was 160 °C, the reaction time was 4 h, the addition amount of Cr-SiO₂–SO₃H was 1 g/g (cellulose), and the volume ratio of [BMIM]Cl to THF was 1:3, the maximum yield of HMF could reach 54.8%, which was 1.49 and 1.34 times the maximum yield of SiO₂–SO₃H and Cr-SiO₂, respectively.