NC State
Wu, Y., Saeed, H. A. M., Li, T., Lyu, G., Wang, Z., Liu, Y., Yang, G., and Lucia, L. A.(2018). "Organic solvent isolation and structural characterization of willow lignin," BioRes. 13(4), 7957-7968.


Autocatalyzed isopropanol-water extraction is a potentially high-value lignin isolation methodology. A solution of isopropanol-water (2-PrOH/ H2O, 7:3, v/v) was used on willow powder (Salix matsudana cv. Zhuliu), at varying temperatures (160 °C to 210 °C) and reaction times (6 h to 12 h). The highest yield (61 wt%) and purity (93.7%) with low weight/number average molecular weight (1681/1061 g/mol) was observed at a treatment temperature and time of 190 °C and 10 h, respectively. Fourier-transform infrared (FTIR) and two-dimensional nuclear magnetic resonance (2D-NMR) spectroscopy indicated that the lignin was composed of syringyl (S) and guaiacyl (G) units that were not severely damaged. More specifically, 31P-NMR showed that S units were dominant. Finally, a majority of glucan was preserved.

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