Theoretical Mechanism on the Cellulose Regeneration from a Cellulose/EmimOAc Mixture in Anti-Solvents.

Zhaoyang Ju,Shaokeng Feng,Minjia Zheng,Liyong Ding,Tingyu Lei,Mengting Yu,Yihang Yu

doi:10.3390/ma15031158

Zhaoyang Ju, Shaokeng Feng + Show 5 more

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https://doi.org/10.3390/ma15031158

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Abstract

The experiments on cellulose dissolution/regeneration have made some achievements to some extent, but the mechanism of cellulose regeneration in ionic liquids (ILs) and anti-solvent mixtures remains elusive. In this work, the cellulose regeneration mechanism in different anti-solvents, and at different temperatures and concentrations, has been studied with molecular dynamics (MD) simulations. The IL considered is 1-ethyl-3-methylimidazolium acetate (EmimOAc). In addition, to investigate the microcosmic effects of ILs and anti-solvents, EmimOAc-nH2O (n = 0–6) clusters have been optimized by Density Functional Theory (DFT) calculations. It can be found that water is beneficial to the regeneration of cellulose due to its strong polarity. The interactions between ILs and cellulose will become strong with the increase in temperature. The H-bonds of cellulose chains would increase with the rising concentrations of anti-solvents. The interaction energies between cellulose and the anions of ILs are stronger than that of cations. Furthermore, the anti-solvents possess a strong affinity for ILs, cation–anion pairs are dissociated to form H-bonds with anti-solvents, and the H-bonds between cellulose and ILs are destroyed to promote cellulose regeneration.

Highlights

Plants and plant-based biomass are abundant sources of renewable feedstocks found across the Earth which contain three dominant components: cellulose, hemicellulose, and lignin [1]
molecular dynamics (MD) simulations for a cellulose/ethyl-3-methylimidazolium acetate (EmimOAc) system, with 16 × 8 (16 glucan chains and each with 8 residues) cellulose bunches (Figure 1) and 320 pairs of EmimOAc filled in a cuboid box using Packmol [32], were performed with the Gromacs 5.1.1 software package
We have considered the influence of different kinds of antisolvents, temperatures, and concentrations on cellulose regeneration

Summary

Introduction

Plants and plant-based biomass are abundant sources of renewable feedstocks found across the Earth which contain three dominant components: cellulose, hemicellulose, and lignin [1]. Apart from its broad applications as a raw material to produce paints, tissues, paper, new structural–functional membranes, and pharmaceutical compounds, cellulose can be used as an appropriate feedstock for biofuel and bioproducts [3,4]. Cellulose usually cannot be dissolved in common solvents, such as alcohol or water [7]. Cellulose can be regenerated from the dissolved cellulose–ILs mixtures when adding anti-solvents, such as water or alcohol [16,17,18]. Cellulose regeneration is one of the most important parts of the utilization of cellulose and its transformation into new functional materials

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