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. Melts of inorganic and organic salts are known as cellulose solvents and reaction medium for the homogeneous conversion of the polymer. However, they are rather expensive and most of them contain large amounts of water, which may induce side reactions. Melts of simple trialkylammonium salts could be an inexpensive alternative. Thus, trialkylammonium carboxylates were synthesized and studied as potential solvents and reaction medium for the homogeneous etherication of cellulose.