An insight into the influence of hydrogen bond acceptors on cellulose/1-allyl-3-methyl imidazolium chloride solution

Although ionic liquids have been well established as effective solvents for the dissolution and processing of natural cellulose fibers, the detailed dissolution mechanism at the molecular level still remains unclear. Herein, the turbidimetric measurement showed that the solubility of cellulose in 1-allyl-3-methyl imidazolium chloride (AmimCl) decreased with increasing temperature. The temperature dependence of the OH stretching vibration band of cellulose in AmimCl was investigated by infrared spectroscopy. The interaction between AmimCl and different hydrogen bond acceptors were investigated by turbidimetry and NMR spectroscopy, which indicated that the excellent compatibility of the hydrogen bond acceptors with AmimCl provides more interaction sites for the hydroxyl groups of the cellulose. In addition, ionic liquids with a similar anionic structure of hydrogen bond acceptors have been synthesized. This study provides a green and safe guide for the preparation of ionic liquids with excellent solubility of cellulose.