Synergistic effect of hetero- and homo-catalysts on the ‘green’ synthesis of 5-hydroxymethylfurfural from chitosan biomass

5-Hydroxymethylfurfural (5-HMF) is an important platform chemical and a sustainable choice in the field of biofuels and bioplastics. The past decade has witnessed significant advancements in the production of 5-HMF using edible feedstocks, like glucose and fructose, with good success. In this investigation, we discuss ‘green’ synthesis of 5-HMF from chitosan using a combination of homogenous and heterogeneous catalyses. Catalysts were screened and the effect of various parameters such as concentrations of chitosan and the catalysts, concentration of acetic acid, reaction temperature and reaction time were studied to identify the process conditions giving maximum yield of 5-HMF. It was found that H-β-zeolite in combination with a minimal concentration of acetic acid resulted in maximum yield, which ranges from 15.27 to 28.22% of 5-HMF, depending on the molecular weight of the parent polymer. Our investigation involves usage of solid acid catalysts, environmentally benign solvents and crustacean waste as the starting material making the process ‘green’ and sustainable.