InCl3-ionic liquid catalytic system for efficient and selective conversion of cellulose into 5-hydroxymethylfurfural

Abstract

In recent decades, 5-Hydroxymethylfurfural (HMF) has been considered as a green platform molecule with a wide range of applications in manufacturing fine chemicals and biofuels. As the most abundant organic material on earth, cellulose has received increasing attention as a potential material for the production of biofuels and bio-based chemicals. Efficient methods for transforming cellulose into HMF need to be developed to achieve the successful commercialization of HMF in the near future. A new process for the efficient and selective conversion of microcrystalline cellulose (MCC) to HMF was developed by using an InCl₃-ionic liquid catalytic system. The effect of reaction conditions, such as reaction time, temperature, catalyst dosage, and various acidic ionic liquids were investigated in detail. The results showed that 45.3% HMF yield and 84.6% MCC conversion were obtained with the presence of 1-methyl-3-(3-sulfopropyl)-imidazolium hydrogen sulfate ([C₃SO₃Hmim][HSO₄]) and dimethylsulphoxide (DMSO) by adding a catalytic amount of InCl₃ under atmospheric pressure within 5 h at 160 °C. Recycling of the [C₃SO₃Hmim][HSO₄] and InCl₃ catalyst exhibited an almost constant activity during five successive trials. A mechanism was proposed to explain the high activity of InCl₃ in [C₃SO₃Hmim][HSO₄].