Super-rapid and highly-efficient esterification of cellulose to achieve an accurate chromatographic analysis of its molecular weight

Herein, a striking anion-tunnel transfer effect was demonstrated in 1-butyl-3-methylimidazolium benzoate (BmimPhCOO) ionic liquid, so a rapid, mild and efficient benzoylation of cellulose is accomplished under catalyst-free condition in BmimPhCOO. In a wide temperature range of 20-80 °C, the equilibrium of reaction is reached within only 15 min, which is much faster than the reported acylation of cellulose. Furthermore, the resultant cellulose tribenzoates have excellent solubility in conventional organic solvents, thus they can be used to accurately reflect the molecular weight and dispersity index of cellulose raw materials by gel permeation chromatography. This method is suitable for various cellulose. Therefore, we found a new principle to realize the extremely-rapid acylation of cellulose, and proposed an effective approach to accurately determine the molecular weight parameters of cellulose.