(490v) Cellulose Dissolution in Ionic Liquids: Link Between Ion Structure and Cellulose Solubility

In recent years, the interest in ionic liquids as new and potentially environmentally friendly solvents for biomass processing has increases dramatically. While a number of ionic liquids have been identified as being capable of dissolving cellulose, lignocellulose and even wood, the structural requirements of the ionic liquid ions for cellulose dissolution remain elusive. Further, the currently used ionic liquids such as 1-ethyl-3-methylimidazolium chloride ([EMIM]Cl) and 1-ethyl-3-methylimidazolium acetate ([EMIM]Ac) are expensive due to multiple processing steps in their preparation. For large-scale processing of biomass into biofuels and chemicals, it is necessary for less costly ionic liquids to be utilized. Therefore, we have examined ionic liquids which are structurally similar to [EMIM]Cl and [EMIM]Ac that are readily prepared in a simple one-step synthesis procedure. This study thus focuses on four imidazolium-based ionic liquids consisting of two aprotic ionic liquids that are known to dissolve cellulose and two protic ionic liquids. The solvation of cellulose and model compounds (D-glucose and cellobiose) in these four ionic liquids, as well as the thermophysical properties of the ionic liquids, have been investigated. The solvation phenomena observed may be explained from the thorough investigation of the salt thermal properties.