Abstract:

The chemical groups and bonds characterization of lignins obtained from juvenile and mature of Chinese Fir were studied by elemental analysis, FTIR and ¹H NMR spectroscopy. The results showed that the average per-C₉-unit formulae of the juvenile and mature of Chinese Fir lignins obtained by acetosolv delignification were C₉H_8.73O_2.57(OCH₃)_0.84 and C₉H_9.01O_2.24(OCH₃)_0.09 respectively. The FTIR and ¹H NMR spectra showed the aromatic skeletal of juvenile of Chinese Fir lignin mainly consisted by G rings and the aromatic skeletal of mature of Chinese Fir lignin had some type S ring structures except G rings and had more aromatic skeletal than that in juvenile wood. There were four types bonds in Chinese Fir lignin. They were β-O-4,β-5,β-β and β-1 In the mature wood, the bonds had a higher content than those in the juvenile wood.

Key words: Chinese Fir, Juvenile wood, Mature wood, Lignin, FTIR, ¹H NMR