Organic Solvent Isolation and Structural Characterization of Willow Lignin

Yinglong Wu, Haroon A. M. Saeed, Tengfei Li, Gaojin Lyu, Zhiwei Wang, Yu Liu, Guihua Yang, Lucian A. Lucia

Abstract


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.

Keywords


Lignin; Characterization; Willow; Isopropanol; 31P-NMR

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Welcome to BioResources! This online, peer-reviewed journal is devoted to the science and engineering of biomaterials and chemicals from lignocellulosic sources for new end uses and new capabilities. The editors of BioResources would be very happy to assist you during the process of submitting or reviewing articles. Please note that logging in is required in order to submit or review articles. Martin A. Hubbe, (919) 513-3022, hubbe@ncsu.edu; Lucian A. Lucia, (919) 515-7707, lucian.lucia@gmail.com URLs: bioresourcesjournal.com; http://ncsu.edu/bioresources ISSN: 1930-2126