The role of 1-methylimidazole as a co-solvent for cellulose in imidazolium based IL solutions

Dissolution of cellulose in ionic liquids (IL) can be facilitated and the viscosity of the resulting solutions can be reduced if a co-solvent is introduced. In this study the molecular solvent N-methylimidazole (MIM) was used as a dispersing agent and co-solvent for dissolution of cellulose in the ionic liquid 1-ethyl-3-methylimidazolium acetate (EMIMAc). It turned out that only a small amount of EMIMAc was needed to dissolve the cellulose, corresponding to an IL to AGU ratio of around 1.5 for 10 % (w/w) cellulose solutions. At the same time, viscosity of the solutions was significantly reduced as a consequence of increasing relative amount of co-solvent, resulting in an optimal solvent to co-solvent ratio for each cellulose concentration.