Ammonium-based cellulose solvents suitable for homogeneous etherification.

New ammonium-based cellulose solvents with triethylmethylammonium- and tributylmethylammonium cations and carboxylate anions were synthesized and investigated as potential solvents for cellulose. Triethylmethylammonium formate was found to dissolve cellulose. Small amounts of formic acid may be used to adjust the melting point of the organic salt and can increase the dissolution velocity of cellulose. Carboxymethylation as a common etherification reaction was investigated in the new ammonium-based system. The watersoluble carboxymethyl cellulose obtained, had a degree of substitution as high as 1.55. An unconventional pattern of substitution was accessible.