α-Etherification in diol pretreatment quenched lignin intermediate and produced a reactive lignin with hydroxyl tails. Hydroxyl tails increased lignin solubilization without cleavage of β-O-4 ether linkages.
Delignification of Broussonetia papyrifera during ethanol organosolv pretreatment was studied. Milled wood lignin (MWL), the ethanol organosolv lignin recovered at 5 min (PL5), 10 min (PL10), and 60 min (PL60) during the pretreatment, and the residual lignin (RL60) after the pretreatment were characterized and compared. GPC results demonstrated that the weight-average molecular weights (M w ) of the ethanol organosolv lignin fractions increased as the pretreatment time extended from 5 to 60 min. 31 P NMR analysis revealed that the content of aliphatic OH decreased in the following order: RL60 < PL60 < PL5 < PL10 < MWL. HSQC NMR results suggested that the contents of syringyl, guaiacyl, p-hydroxybenzoate unit, phenylcoumaran, and resinol in the solubilized lignin fractions were significantly changed during the pretreatment. In addition, a significant portion of β-O-4 interunit linkages of lignin was cleaved during the pretreatment, leading to the formation of stilbene structures in lignin samples such as PL60.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.