Ionic liquids as reaction medium in cellulose functionalization

The application of different ionic liquids (IL), namely 1-N-butyl-3-methylimidazolium chloride ([C(4)mim]Cl-+(-)), 3-methyl-N-butyl-pyridinium chloride and benzyldimethyl(tetradecyl)ammonium chloride were investigated as solvents for cellulose. The ILs used have the ability to dissolve cellulose with a degree of polymerization in the range from 290 to 1200 to a very high concentration. Using [C(4)mim]Cl-+(-), no degradation of the polymer appears. By C-13 NMR measurement it was confirmed that this IL is a so-called non-derivatizing solvent. [C(4)mim]Cl-+(-) can be applied as a reaction medium for the synthesis of carboxymethyl cellulose and cellulose acetate. Without using any catalyst, cellulose derivatives with high degree of substitution could be prepared.