Research advances on functional modification of lignocellulose under deep eutectic solvents and their applications

Different from ionic liquids or other solvents, deep eutectic solvent (DES), as a novel environmentally friendly solvent, owns the advantages of easy and flexible preparation, low cost and high efficiency, and shows great potential applications in the pretreatment of lignocellulose. A series of important advances have been made related to the dissolution, component separation and modification of lignocellulose in DES system in recent years. The chemical modification with smaller impact on the environment can be achieved in DES system when compared to traditional ionic liquid and other organic solvent systems. Moreover, the modified lignocellulose has been widely applied in the preparation of nanofibers and the construction of composite materials. This article reviews the research advances in the cationization, esterification and other derivatizations of lignocellulose in the DES system. The applications of thus pretreated and modified lignocellulose in nano-dispersion, functional compositing are also included. Finally, the development and challenges of lignocellulose modification based on DES system are discussed.