The Cellulose Regeneration in Imidazolium-based Ionic Liquids and Anti-solvents Mixtures: A DFT study

作者：Lanlan Fu, Zhaoyang Ju, Mengting Yu, Huaying Luo, Cheng Zhang, Ximing Zhang, Haixiang Cheng, Minjia Zheng, Chengsheng Ge · 发表于：Research Square · 年份：2022 · DOI：10.21203/rs.3.rs-1628782/v1 · 研究领域：Advanced Cellulose Research Studies、Lignin and Wood Chemistry

Abstract Cellulose can be dissolved in ionic liquids (ILs) and it can be recovered by adding anti-solvent such as water or alcohol. Besides, the regenerated cellulose can be used for textiles, degradable membranes, hydrogels/aerogels, etc . But the regenerated mechanism of cellulose remains ambiguous. In this work, a Density Functional Theory (DFT) calculation is reported for the cellulose regeneration from a cellulose/1- n -butyl-3-methylimidazolium acetate (BmimOAc)/water mixture. To investigate the microcosmic effects of the anti-solvents, we analyzed the structures and H-bonds of BmimOAc- n H 2 O and cellobiose-ILs- n H 2 O ( n = 0–6) clusters. It can be found that when n ≥ 5 in the BmimOAc- n H 2 O clusters, the solvent-separated ion pairs (SIPs) play a dominant position in the system. With the increasing numbers of water molecules, the cation-anion interaction can be separated by water to reduce the effects of ILs on cellulose dissolution. Furthermore, the BmimOAc- n H 2 O and cellobiose-ILs ( n = 0–6) clusters tend to be a more stable structure with high hydration in an aqueous solution. When the water molecules were added to the system, H-bonds can be formed among H 2 O, the hydroxyl of cellulose, and the oxygen of OAc. Therefore, the interactions between cellobiose and ILs will be decreased to promote cellulose regeneration. This work would provide some help to understand the mechanism of the cellulose regeneration from the view of theoretical calculation.