Application of deep eutectic solvents in biomass pretreatment and conversion

Biomass is renewable, abundant, cheap, biocompatible, and biodegradable materials and has been used to produce chemicals, materials, energy, and fuels. However, most of the biomass, especially most of the biomass polymers are not soluble in common solvents, which hinders their pretreatment and conversion. Deep eutectic solvents (DESs) are environmental-friendly, cheap, and highly tunable, with high solubility, which renders them potential applications in biomass pretreatment and conversion. They could be used as solvents or catalysts and so on. This paper intends to review the application of DESs for the pretreatment of biomass and conversion of biomass to value-added products. We focus on the following topics related to biomass and DESs: (1) DESs for the pretreatment of biomass; (2) DESs for the dissolution and separation of biomass or extraction of chemicals from biomass; (3) DESs for biomass conversion; (4) Drawbacks, and recyclability of DESs for pretreatment and conversion of biomass.