Side reaction of cellulose with common 1-alkyl-3-methylimidazolium-based ionic liquids

Ionic liquids with 1-alkyl-3-methyl-imidazolium cations react at C-2 with cellulose at its reducing end, forming a carbon–carbon bond. The reaction is strongly catalyzed by bases, such as the commonly present impurities in ILs, imidazole, and 1-methylimidazole. The direct reaction was verified by means of 13C-isotopical labeling and with the help of an IL that carried a fluorescence label which was transferred to cellulose upon the reaction. In solutions of cellulose in alkylmethylimidazolium ILs, both the ionic liquid and the cellulose are evidently not inert.