Robust ionic liquid/ethanolamine-superbase solvents enable rapid, efficient and mild dissolution of lignocellulosic biomass

Abstract

Dissolution of lignocellulose is of significant importance for its utilization and transformation. However, it remains a great challenge to efficiently and rapidly dissolve lignocellulose under mild conditions owing to the significant lack of efficient solvents for lignocellulose dissolution. Herein, robust solvent systems were designed by a combination of ionic liquids (ILs), ethanolamine (EA), and organic superbases for the dissolution of lignocellulose. It was observed that the prepared solvents (denoted as the IL/EA-superbase) could efficiently dissolve lignocellulose at mild temperatures (below 100 °C). In particular, the EmimOAc/EA-DBN system showed the best performance, and the solubility values of Populus tomentosa, sugarcane bagasse and Miscanthus giganteus at 90 °C could reach up to 3.8%, 9.5% and 20% (g per 100 g solvent), respectively. It was revealed that EA-superbase effectively participated in the interaction between ILs and lignocellulose, thus promoting the dissolution process. A systematic study revealed that the good performance of the developed solvents toward lignocellulose dissolution resulted from the synergistic effect of the three constructed components to make the solvent have a suitable capacity for the formation of hydrogen-bonding and an appropriate microstructure.