Characterization of milled wood lignin and ethanol organosolv lignin from miscanthus

摘要

Ethanol organosolv lignin extracted from Miscanthus × giganteus (using the following conditions: T = 190 ℃, t = 60 min, sulfuric acid = 1.2% w/w, EtOH/H_2O = 0.65) and milled wood lignin from Miscanthus × giganteus were subjected to a comprehensive structural characterization by ~(13)C, ~(31)P NMR, FTIR, UV spectroscopies and size exclusion chromatography. The results showed that Miscanthus lignin is an H/G/S type (4%, 52%, 44% respectively) with ～0.41 β-O-4 linkage per aromatic ring and contains coumarylate linkages (0.1/Ar). It was shown that during organosolv treatment, cleavage of β-0-4 linkages and of ester bond (acetyl and coumaryl residues) was the major mechanisms of lignin breakdown but the process did not significantly change the core of the lignin structure.