Effect of temperature on the interaction of cellulose/1-allyl-3-methyl imidazolium chloride solution

Abstract

Ionic liquids have provided an efficient way for dissolving cellulose, but the study of its dissolution mechanism is still a major challenge. In this paper, in-situ FTIR spectroscopy, two-dimensional correlation spectrum (2Dcos) and in-situ 1H NMR spectroscopy were used to investigate the interaction between cellulose and 1-allyl-3-methyl imidazolium chloride ([Amim][Cl]) during heating. The results reveal that as the temperature increases, the water in [Amim][Cl] is gradually evaporated, and the hydrogen-bonding interaction between the hydroxyl groups in cellulose and [Amim][Cl] is destroyed. Combined with the in-situ infrared results, it can be inferred from the 2Dcos spectrum that the hydroxyl groups of cellulose not only form hydrogen bonds with C4,5-H and C2H on the [Amim][Cl] cations, but also form hydrogen bonds with chloride ions in [Amim][Cl], thus cellulose can form hydrogen bonds with both the cations and anions of [Amim][Cl]. This is the main reason why [Amim][Cl] has good cellulose solubility.