Structural Characterization of Lignin in the Process of Cooking of Cornstalk with Solid Alkali and Active Oxygen

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• 作者：Qiulin Yang ; Jianbin Shi ; Lu Lin ; Junping Zhuang ; Chunsheng Pang ; Tujun Xie ; Ying Liu
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2012
• 出版时间：May 9, 2012
• 年：2012
• 卷：60
• 期：18
• 页码：4656-4661
• 全文大小：295K
• 年卷期：v.60,no.18(May 9, 2012)
• ISSN：1520-5118

文摘

A novel, efficient, and environmentally friendly technology is used in cornstalk cooking, active oxygen (O₂ and H₂O₂) cooking with solid alkali (MgO). After the cooking, the milled wood lignin in the raw material and pulp and the water-soluble and insoluble lignin in the yellow liquor were all characterized by attenuated total reflectance Fourier transform infrared spectroscopy and two-dimensional heteronuclear single-quantum coherence NMR. The results showed that the cooking procedure with solid alkali and active oxygen had a high selectivity for delignification, which could remove 85.5% of the lignin from the raw material. The syringyl (S/S鈥?S鈥? units could be dissolved preferentially because of their high reactivity, and a novel guaiacyl unit with a carbonyl group (G鈥? was generated in the cooking process. Moreover, during the cooking, the 尾-O-4鈥?(A/A鈥?A鈥? structures as the main side-chain linkages in all the lignins could be partly broken and the 尾-O-4鈥?(A鈥? with a ring-conjugated structure was readily attacked by oxygen, whereas the H unit and 尾-5鈥?and 尾-尾鈥?structures were found to stay stable without characteristic reaction.

Keywords:

solid alkali; active oxygen; cornstalk; lignin