Cellulose ethers have historically been synthesized in a heterogeneous process where the cellulose remains undissolved throughout the reaction. Discovery of novel, homogeneous etherification processes has been limited due to low electrophile efficiency, incompatibility with aqueous hydroxide, or hydrophobicity of the electrophile. In this work, cellulose ethers were obtained from a homogeneous process which circumvented many of these problems by utilizing small, hydrophilic electrophiles and a binary ionic liquid system to improve electrophile efficiency. By modulating ionic liquid composition, we were able to nearly double reaction efficiency from 16% to 30% and determined that at least 1.0 equivalent of basic ionic liquid was required for sufficient solubilization of the cellulose. Additionally, a moderate amount of DMSO co-solvent was required to improve mass transport by reducing solution viscosity while maintaining cellulose solubility. Investigations into the reaction kinetics showed that the reaction took approximately 30 minutes to complete at 100 °C, and that the reaction rate doubled for every 10 °C increase in temperature. A simple, first-order kinetics model showed that the reaction followed Arrhenius-type behavior, indicating a single controlling reaction mechanism, with an apparent activation barrier similar to other etherification reactions in the literature. We demonstrated that the system was compatible with a wide range of glycidyl electrophiles, capable of producing an array of cellulose ethers with different aqueous/organic solubility.
