76246-81-6Relevant academic research and scientific papers
Profiling of the formation of lignin-derived monomers and dimers from: Eucalyptus alkali lignin
Hu, Zhenhua,Li, Suxiang,Lu, Fachuang,Shi, Lanlan,Wang, Chen,Yue, Fengxia,Zhang, Han,Zhao, Chengke
, p. 7366 - 7375 (2020/11/18)
Lignin is a renewable and the most abundant aromatic source that can be used for extensive chemicals and materials. Although approximately 50 million tons of lignin are produced annually as a by-product of the pulp and paper industry, it is currently underutilized. It is important to know the structural features of technical lignin when considering its application. In this work, we have demonstrated the formation of low-molecular-weight constituents from hardwood (Eucalyptus) lignin, which produces much more low-molecular-weight constituents than softwood (spruce) lignin, after a chemical pulping process, and analyzed the micromolecular compositions in the alkali lignin after fractionation by dichloromethane (DCM) extraction. By applying analytical methods (gel-permeation chromatography, 2D NMR and GC-MS) with the aid of evidence from authenticated compounds, a great treasure trove of lignin-derived phenolic compounds from Eucalyptus alkali lignin were disclosed. Except for some common monomeric products, as many as 15 new lignin-derived monomers and dimers including syringaglycerol, diarylmethane, 1,2-diarylethanes, 1,2-diarylethenes, (arylvinyl ether)-linked arylglycerol dimers and isomeric syringaresinols were identified in the DCM-soluble fraction. Regarding the formation and evolution of the Cα-condensed β-aryl ether structure, a novel route that is potentially responsible for the high content of β-1 diarylethenes and diarylethanes in the lignin low-molecular-weight fraction, in addition to the β-1 (spirodienone) pathway, was proposed. This work not only provides novel insights into the chemical transformation of S-G lignin during the alkali pulping process, but also discovered lignin-derived phenolic monomers and dimers that can potentially be used as raw materials in the chemical or pharmaceutical industries. This journal is
Domino lignin depolymerization and reconnection to complex molecules mediated by boryl radicals
Hong, Longcheng,Pfeiffer, Janin,Spielmeyer, Astrid,Wegner, Hermann A.
, p. 3008 - 3014 (2020/06/17)
Chemical degradation of lignin has attracted increasing interest due to its potential for producing chemicals from renewable resources. Herein, we present a new transition metal free degradation procedure utilizing DDQ-oxidation and boryl radical mediated degradation, followed by reconnection of a monomer intermediate to a new dimer in a domino process. Our results include the selective degradation of oxidized β-O-4 model compounds by a boryl radical initiated with a catalytic amount of 4-(4-pyridinyl)benzonitrile and bispinacolborane B2(pin)2 as well as its application to organosolv lignin. This sequential procedure expands the toolbox for lignin degradation from simple depolymerization to high-value products by incorporating bond forming transformations within the process, and also provides a new transition-metal free method for the construction of 1,6-diketone fragments.
VO(acac)2 catalyzed oxidative deprotection of oximes, hydrazones, and semicarbazones
De, Surya Kanta
, p. 4409 - 4415 (2007/10/03)
Oximes, hydrazones, and semicarbazones undergo facile deprotection in the presence of a catalytic amount of vanadyl acetylacetonate and hydrogen peroxide in acetone at room temperature.
