Insights into cellulose deconstruction and pseudo-lignin formation during deep eutectic solvent treatment

To clarify the formation of pseudo-lignin during pretreatment is vital to high-value utilization of lignocellulose. In this study, hydrothermally treated bamboo and α -cellulose were employed to investigate the generation of pseudo-lignin during deep eutectic solvent (DES) treatment. It is found that pseudo-lignin not only contains some characteristic substructures of natural lignin, but also has the structural characteristics of phenol-type oxygenated and furan-type compounds. It is proposed that chloride anion probably stimulates the deconstruction of crystalline cellulose to form pseudo-lignin. Besides, it’s suggested that the change in lignin content can be reflected from the viewpoint of acid-soluble lignin to minimize the interference from pseudo-lignin, and there may exist a competition between 5-chloromethylfurfural production and pseudo-lignin formation. This study provides a feasible route to produce pseudo-lignin from α -cellulose via DES and contributes to a better understanding of pseudo-lignin formation.