The first example of chemical depolymerization of lignin involving the redistribution mechanism with phenols in water with a copper catalyst was demonstrated. By using this new method, lignin can be depolymerized under mild conditions such as at 80 °C, atmospheric pressure. This invention is the first demonstration of the depolymerization of lignin using chemical degradation with phenols. The depolymerized oligomeric lignin can be repolymerized and form a polymer by the esterification of hydroxyl groups in the depolymerized oligomeric products with sebacoyl chloride. † Electronic supplementary information (ESI) available. See

Nowadays, ionic liquids (ILs) have been recognized as a promising way to fractionate biomass. In this study, we discuss how lignin depolymerization was achieved via the redistribution mechanism with phenols in ionic liquids. Two ionic liquids (1-ethyl-3-methylimidazolium xylenesulfonate [emim]­[ABS] and 1-butyl-3-methylimidazolium methylsulfate [bmim]­[MeSO4]) were selected as a solvent for lignin depolymerization. Before embarking on lignin depolymerization, two selected lignins (organosolv lignin and Klason lignin) were characterized based on their chemical structure and molecular weight. The depolymerized results show that the two lignins (organosolv lignin and Klason lignin) can be extensively depolymerized under oxidative conditions using a Cu/EDTA complex in the presence of a monomeric phenol (4-tert-butyl-2,6-dimethylphenol) that is blocked from oxidative coupling in the ortho and para positions at temperatures of 180 °C.

Gel Permeation Chomatography (GPC) The molecular weights of synthesized PPO were determined by GPC performed on a Tosoh EcosHLC-8320 Gel Permeation Chromatography apparatus equipped with both refractive index (IR) and ultraviolet (UV) detectors (UV detection, λ = 280 nm) using Tosoh alpha 4000 and 2000 columns and DMF was used as the solvent. Calibration curves were obtained by using polystyrene standards ranging between M n 500-2.89 × 10 6 gmol-1. I-HRP preparation I-HRP was synthesised using previous reported method in our paper-Zhao, Z.;

We investigated a photocatalytic heterogeneous system using recyclable MnO2 under the irradiation of blue light for lignin oxidation.