BIOMASS INTO CHEMICALS: GREEN CHEMICAL CONVERSION OF CARBOHYDRATES (FRUCTOSE, SUCROSE AND GLUCOSE) INTO 5-HYDROXYMETHYLFURFURAL IN PYRIDINIUM DICATIONIC IONIC LIQUID

摘要

Biomass is considered to be an important renewable source for securing future energy supply, production of fine chemicals and sustainable development. There are currently a number of catalysts that are active in the dehydration of sugars to form 5-hydroxymethylfurfural (HMF). However, most of them also promote side reactions that form undesired by-products, and rehydrate HMF to form levulinic acid and formic acid. A simple and an efficient method to produce pure HMF from abundant renewable carbohydrates in high yield at low energy cost must be developed before a biorefinery platform can be built on the basis of this substrate. Demands by green chemistry, the development of new environmentally friendly solvents has created a fast-growing interest. During the past decades, design and synthesis of new multifunctional ionic liquids (ILs) attracted attention due to their interesting properties compared with traditional molecular solvents, such as undetectable vapour pressure, wide liquid temperature range special solubility for many organic or inorganic compounds, and favourable environments. In this work the dehydration of sugars has been studied with different kinds of pyridinium based dicationic ionic liquids. So far many researchers were used ionic liquid as solvent and metal chlorides or other additives as a catalyst for the conversion of sugars. However, in these reported works, the ILs mainly played a role as the solvent and was consumed in considerably large amounts. In this work, we used catalytic amount of different kinds of pyridinium dicationic ionic liquids with dimethyl sulfoxide (DMSO) and without DMSO. They have shown good performance and gave excellent yield for 5 HMF. The results strongly suggested that an ionic liquid can play an important role in exploring new efficient and easy to use processes for the production of 5 HMF. The ionic liquids used in this study will benefit many biofuel-related applications.