| Abstract:The lignins were extracted from kraft pulping black liquor of Eucalyptus by ethanol sulfuric acid and sulfuric acid respectively. These lignins were analysed and characterized by elemental analysis、 FT-IR、 UV spectrum and 1HNMR.The results showed that the lignin separated by ethanol sulfuric acid （CSL） presented typical characteristics of lignin of hardwood, which included syringyl（S） and guaiacyl（G）units, and the amount of S units was higher than the G units; CSL main linkage bonds were β-O-4、 β-1、 β-5、 β-β, and it contained many more free carbonyl, methoxy and hydroxyl groups and other active groups; CSL composition elements were mainly C,H,O,N, and the contents were 62.55%、 5.57%、 29.54%、 0.15%, respectively,its theoretical molecular formula was C10H10.68O3.54N0.02 . Compared with the lignin extracted directly from the black liquor(SL), CSL had less complex functional groups and molecular． |
