title: Characterization of changes of lignin structure in the processes of cooking with solid alkali and different active oxygen.
abstract: The cooking with solid alkali and active oxygen has a high selectivity for delignification. In the present work, the O(2) and H(2)O(2) were separately combined with MgO used in cornstalk cooking for investigating their effects on delignification. After cooking, the lignins in raw material, pulp, and yellow liquor were all characterized by HSQC NMR. The results showed that the syringyl (S/S'/S″) units and β-O-4' (A/A'/A″) structures had different reactivity in the cooking with MgO and H(2)O(2) due to their different structures on side-chains. Whereas the syringyl (S/S'/S″) units could be completely decomposed when the MgO and O(2) were used, and the β-O-4' (A/A'/A″) structures could be partly degraded. A novel structure G' unit with a carbonyl group was only generated in the cooking with MgO and O(2). In addition, the H unit, non-phenolic β-β' (B) and β-5' (C) structures were all stable in both of the two cooking processes.
authors.affiliation: State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, Guangdong Province, China. yanglin.223@163.com
authors.forename: Qiulin
authors.initials: Q
authors.lastname: Yang
authors.forename: Jianbin
authors.initials: J
authors.lastname: Shi
authors.forename: Lu
authors.initials: L
authors.lastname: Lin
authors.forename: Lincai
authors.initials: L
authors.lastname: Peng
authors.forename: Junping
authors.initials: J
authors.lastname: Zhuang
mesh_terms: D000468:Alkalies / Q000737:chemistry*; D006358:Hot Temperature; D006861:Hydrogen Peroxide / Q000737:chemistry; D008031:Lignin / Q000737:chemistry*; D008277:Magnesium Oxide / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D017382:Reactive Oxygen Species / Q000737:chemistry*; D003313:Zea mays / Q000737:chemistry
chemical_list: D000468:Alkalies; D017382:Reactive Oxygen Species; D008277:Magnesium Oxide; D008031:Lignin; D006861:Hydrogen Peroxide