Chemical Transformations of Lignin Under the Action of 1-Butyl-3-Methylimidazolium Ionic Liquids: Covalent Bonding and the Role of Anion.

ABSTRACT: 1-Butyl-3-methylimidazolium (bmim) ionic liquids (ILs) are widely used for lignocellulose fractionation, yet their role extends beyond mere solvents. This study revealed that bmim-based ILs act as active chemical reagents, modifying the lignin structure in an anion-dependent manner. Thermal treatment (80-150 °C) of spruce dioxane lignin with [bmim]OAc, [bmim]Cl, and [bmim]MeSO₄ resulted in two distinct transformation pathways. In [bmim]MeSO₄, acidic catalysis dominates, leading to lignin condensation (increase in weight-average molecular weight, M_w, to 15.2 kDa at 150 °C) and intense sulfur incorporation (up to 9.9%) via anion-derived methylation/sulfation. Conversely, [bmim]OAc promotes depolymerization (decrease in M_w to 3.6 kDa) and efficient

SUBMITTER: Belesov AV 

PROVIDER: S-EPMC12691707 | biostudies-literature | 2025 Nov

REPOSITORIES: biostudies-literature