Easy and Efficient Recovery of EMIMCl from Cellulose Solutions by Addition of Acetic Acid and the Transition from the Original Ionic Liquid to an Eutectic Mixture.

Huan Zhang,Aitana Tamayo,Francisco del Monte,Pilar F. Seriñan,María Luisa Ferrer,María C. Gutiérrez,Fausto Rubio Alons,María A. Rodríguez,Andreea Ionita

doi:10.3390/molecules27030987

Abstract

Ionic liquids (ILs) and deep eutectic solvents (DESs) are the two most widely used neoteric solvents. Recently, our group described how the simple addition of acetic acid (AcOH) to 1-Ethyl-3-methylimidazolium chloride (EMIMCl) could promote the transition from the original IL to an eutectic mixture of EMIMCl and AcOH. Herein, we studied how cellulose regeneration and EMIMCl recovery from EMIMCl solutions of cellulose could be benefited by the significant differences existing between EMIMCl- and EMIMCl·AcOH-based mixtures and the easy switching from one to the other. Finally, we also demonstrated that the transition could also be accomplished by addition of acetic anhydride and water so that the process could be eventually useful for the achievement of highly acetylated cellulose.

Highlights

Both ionic liquids (ILs) and deep eutectic solvents (DESs) have become the two most popular neoteric solvents
Very recent studies performed in our group by NMR spectroscopy and molecular dynamics simulations provided a more detailed description of the HBs formed between Ethyl3-methylimidazolium chloride (EMIMCl) and acetic acid (AcOH as the HBD) that allowed one eutectic mixture to be achieved [28]
The subsequent cellulose coagulation and IL recovery accounts on the greenness and economic viability of an IL process for biomass processing

Summary

Introduction

Both ionic liquids (ILs) and deep eutectic solvents (DESs) have become the two most popular neoteric solvents. Very recent studies performed in our group by NMR spectroscopy and molecular dynamics simulations provided a more detailed description of the HBs formed between EMIMCl and acetic acid (AcOH as the HBD) that allowed one eutectic mixture to be achieved [28].

Results

Conclusion