Ionic liquids of 1-carboxymethyl-3-ethylimidazolium chloride ([CmEIM]Cl), 1-methoxyethyl- 3-ethylimidazolium chloride ([C2OC1-EIM]Cl) and 1-[2-(2-chloroethoxy)ethyl]-3-ethylimidazolium chloride ([Cl-C2OC2-EIM]Cl) were synthesized, and their chemical structures were confirmed by FT-IR and 1H NMR. Dissolution of cotton cellulose in these three kinds of ionic liquids was studied. The chemical structures, morphologies and crystalline forms of the original cellulose and the regenerated cellulose were analyzed by FT-IR, XRD and SEM, respectively. The results show that the solubility of cotton cellulose in [C2OC1-EIM]Cl was best. In the dissolution progress, the solubility of cotton cellulose in the ionic liquids increased with increasing temperature, but the DP decreased, especially in [Cl-C2OC2-EIM]Cl. It was suggested that the solubility of cotton cellulose in [CmEIM]Cl containing carboxyl decreased because of its intermolecular and intramolecular hydrogen bonds. The ionic liquids with long side chains exhibited worse dissolution ability for cotton cellulose.

Key words: ionic liquid, synthesis, cotton cellulose, dissolution, regeneration