LAUSR

Many valorization approaches for lignin rely on its organic solvent (organosolv) extraction. However, the extraction severity required to obtain high lignin extraction yields generally results in low-quality lignin for downstream processing. To better understand the secondary reaction pathways and kinetics related to molecular alterations which result from severe organosolv extraction, extractions were conducted at temperatures of 150, 180, and 210 °C.  Lignin was collected at residence times between 0.25 and 18 h and analyzed using nuclear magnetic resonance techniques to quantify the concentrations of key chemical moieties that appear or disappear upon reactions to lignin molecules during and after their fractionation from biomass. The kinetics of chemical moiety evolution has been modeled as processes in-series. In these models, pseudo first-order kinetics were used to describe the change in concentration of chemical moieties on extracted lignin as a function of residence time.