A novel strategy for highly efficient conversion of cellulose into 5-hydroxymethylfurfural using green and effective stepwise catalytic systems

In this study, a green and effective stepwise catalytic system for cellulose conversion to 5-hydroxymethylfurfural (HMF) is reported. In a pretreatment process, very fast (15 min) dissolution of cellulose was achieved at a low temperature of 70 °C, utilizing ZnBr 2 ·4H 2 O as the best dissolution solvent, which to improve the reactivity of cellulase for raw cellulose and increase efficiency of cellulose degradation. Enzyme-inorganic hybrid nanoflowers (Cellulase@β-glucosidase/Zn 3 (PO 4 ) 2 -NF and Glucose isomerase@Zn 3 (PO 4 ) 2 -NF) with different morphological structures were prepared to act as biocatalyst in the sequential conversion of pretreated cellulose to glucose and glucose to fructose. HCl was applied catalyst for dehydration of fructose to 5-HMF in a water/tert-butanol biphasic system. Under optimal reaction conditions, the yield of 5-HMF for the overall reaction from cellulose was about 21.6%. A feasibility route for green conversion of cellulose to 5-HMF is reported. Graphical abstract