2196-18-1Relevant articles and documents
Visible light-enabled selective depolymerization of oxidized lignin by an organic photocatalyst
Hao, Zhongkai,Jiang, Huating,Li, Shuyuan,Tong, Min,Wang, Kaixuan,Xiao, Yao,Yang, Yanan,Zhang, Fang
supporting information, p. 11243 - 11246 (2020/10/06)
The development of an economic, environmental-friendly and energy-saving process for the selective depolymerization of lignin is an outstanding challenge. Herein, a novel and efficient visible-light-induced photocatalytic process for the selective depolymerization of lignin model compounds and organosolv lignin was first developed by using perylene diimide (PDI) as a metal-free organocatalyst. Interestingly, it can completely decompose the oxidized lignin models to phenolic and ketone fragmentation molecules with very high selectivity at room temperature under visible light illumination. Furthermore, the use of a home-made photocatalytic continuous-flow reactor efficiently shortened the reaction time within an hour. Even for organosolv lignin, nearly 86% mass ratio of lignin was degraded to low-molecular-mass monoaromatic or diaromatic products. We found that superior performances were realized by single-electron transfer (SET) from the photoexcited strongly reducing PDI˙?anion to the ketone groups of the β-O-4 linkage in the lignin.
Sphingobacterium sp. T2 Manganese Superoxide Dismutase Catalyzes the Oxidative Demethylation of Polymeric Lignin via Generation of Hydroxyl Radical
Rashid, Goran M. M.,Zhang, Xiaoyang,Wilkinson, Rachael C.,Fül?p, Vilmos,Cottyn, Betty,Baumberger, Stéphanie,Bugg, Timothy D. H.
, p. 2920 - 2929 (2018/10/20)
Sphingobacterium sp. T2 contains two extracellular manganese superoxide dismutase enzymes which exhibit unprecedented activity for lignin oxidation but via an unknown mechanism. Enzymatic treatment of lignin model compounds gave products whose structures were indicative of aryl-Cα oxidative cleavage and demethylation, as well as alkene dihydroxylation and alcohol oxidation. 18O labeling studies on the SpMnSOD-catalyzed oxidation of lignin model compound guiaiacylglycerol-β-guaiacyl ether indicated that the an oxygen atom inserted by the enzyme is derived from superoxide or peroxide. Analysis of an alkali lignin treated by SpMnSOD1 by quantitative 31P NMR spectroscopy demonstrated 20-40% increases in phenolic and aliphatic OH content, consistent with lignin demethylation and some internal oxidative cleavage reactions. Assay for hydroxyl radical generation using a fluorometric hydroxyphenylfluorescein assay revealed the release of 4.1 molar equivalents of hydroxyl radical by SpMnSOD1. Four amino acid replacements in SpMnSOD1 were investigated, and A31H or Y27H site-directed mutant enzymes were found to show no lignin demethylation activity according to 31P NMR analysis. Structure determination of the A31H and Y27H mutant enzymes reveals the repositioning of an N-terminal protein loop, leading to widening of a solvent channel at the dimer interface, which would provide increased solvent access to the Mn center for hydroxyl radical generation.
GUAIACYL VINYL KETONE PRODUCTION METHOD
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Paragraph 0056-0057, (2016/10/08)
PROBLEM TO BE SOLVED: To provide a guaiacyl vinyl ketone production method that has higher reaction efficiency and is better suited to industrial-scale production than conventional techniques. SOLUTION: The purpose is achieved by a method of producing high-purity guaiacyl vinyl ketone efficiently under moderate conditions, the method including a step of obtaining guaiacyl vinyl ketone by bringing a basic substance and a 3-halogen-1-(4-hydroxy-3-methoxyphenyl)-1-propanone represented by general formula (1) into contact in a solvent. COPYRIGHT: (C)2015,JPOandINPIT