scholarly journals Electronic and bite angle effects in catalytic C–O bond cleavage of a lignin model compound using ruthenium Xantphos complexes

2017 ◽  
Vol 7 (3) ◽  
pp. 619-626 ◽  
Author(s):  
Luke Shaw ◽  
D. M. Upulani K. Somisara ◽  
Rebecca C. How ◽  
Nicholas J. Westwood ◽  
Pieter C. A. Bruijnincx ◽  
...  
Keyword(s):  
Model Compound ◽  
Bond Cleavage ◽  
Electronic Effects ◽  
Ether Bond ◽  
Lignin Model Compound ◽  
Bite Angle ◽  
Lignin Model ◽  
Ether Bond Cleavage

Bite angle and electronic effects on the ruthenium–diphosphine catalysed ether bond cleavage of the lignin β-O-4 model compound 2-phenoxy-1-phenylethanol were tested.

scholarly journals Revisiting the mechanism of β-O-4 bond cleavage during acidolysis of lignin VII: acidolyses of non-phenolic C6-C2-type model compounds using HBr, HCl and H2SO4, and a proposal on the characteristic action of Br− and Cl−

2020 ◽  
Vol 66 (1) ◽  
Author(s):  
Qiaoqiao Ye ◽  
Tomoya Yokoyama
Keyword(s):  
Model Compound ◽  
Bond Cleavage ◽  
Type Model ◽  
Enol Ether ◽  
Lignin Model Compound ◽  
Benzyl Cation ◽  
Acid Type ◽  
Unstable Compound ◽  
Lignin Model ◽  
Acidolysis Reaction

AbstractA non-phenolic C6-C2-type lignin model compound with the β-O-4 bond, 2-(2-methoxyphenoxy)-1-(3,4-dimethoxyphenyl)ethanol (I), was acidolyzed in aqueous 82% 1,4-dioxane containing HBr, HCl, or H2SO4 with a concentration of 0.2 mol/L at 85 ℃ to examine the differences between these acidolyses. Compound I primarily converted to an enol ether compound, 1-(2-methoxyphenoxy)-2-(3,4-dimethoxyphenyl)ethene (II), via the benzyl cation followed by acidolytic β-O-4 bond cleavage regardless of the acid-type, although the disappearance rates of compound I were remarkably different (HBr > HCl >> H2SO4). Acidolyses of compound II using these acids under the same conditions showed a similar tendency, but the rate differences were much smaller than in the acidolyses of compound I. Acidolyses of the α-methyl-etherified derivative of compound I (I-α-OMe) using these acids under the same conditions suggested that the formation rates of the benzyl cation from compound I-α-OMe (also from compound I) are not largely different between the acidolyses using these acids, but those of compound II from the benzyl cation are remarkably different. Acidolysis of the α-bromo-substituting derivative of compound I (I-α-Br) using HBr under the same conditions showed a characteristic action of Br¯ in the acidolysis. Br¯ adds to the benzyl cation generated from compound I or I-α-OMe to afford unstable compound I-α-Br, resulting in acceleration of the formation of compound II and of the whole acidolysis reaction.

Selective oxidative C–C bond cleavage of a lignin model compound in the presence of acetic acid with a vanadium catalyst

2015 ◽  
Vol 17 (11) ◽  
pp. 4968-4973 ◽  
Author(s):  
Yangyang Ma ◽  
Zhongtian Du ◽  
Junxia Liu ◽  
Fei Xia ◽  
Jie Xu
Keyword(s):  
Acetic Acid ◽  
Molecular Oxygen ◽  
Model Compound ◽  
Bond Cleavage ◽  
Vanadium Catalyst ◽  
Lignin Model Compound ◽  
Lignin Model

The solvent has great effects on vanadium-catalyzed oxidative C–C bond cleavage of 2-phenoxy-1-phenylethanol with molecular oxygen.

Decomposition of a phenolic lignin model compound over organic N-bases in an ionic liquid

Holzforschung ◽  
2010 ◽  
Vol 64 (5) ◽  
Author(s):  
Songyan Jia ◽  
Blair J. Cox ◽  
Xinwen Guo ◽  
Z. Conrad Zhang ◽  
John G. Ekerdt
Keyword(s):  
Ionic Liquid ◽  
Model Compound ◽  
Bond Cleavage ◽  
Organic N ◽  
Alkyl Ether ◽  
Cleavage Reaction ◽  
Process Step ◽  
Lignin Model Compound ◽  
Lignin Model ◽  
Lignin Depolymerization

Abstract Lignin depolymerization is a necessary process step in utilizing the carbohydrates in biomass and in potentially converting the lignin into a chemical feedstock. Lignin contains several aryl-alkyl ether linkages and the β-O-4 linkage is dominant among lignins. Base-mediated cleavage of the β-O-4 bond in a lignin model compound, guaiacylglycerol-β-guaiacyl ether, is reported. Ionic liquids have shown promise in a variety of biomass processes and this study explores the potential to use an ionic liquid solvent (1-butyl-2,3-dimethylimidazolium chloride) and non-aqueous bases in cleaving the β-O-4 bond. N-bases of varying basicity and structure were used at temperatures up to 150°C. The cleavage reaction was not found to be catalytic. Among all the tested N-bases, 1,5,7-triazabicyclo[4.4.0]dec-5-ene was the most active, leading to more than 40% β-O-4 ether bond cleavage, and the higher activity is probably associated with the exposed nature of the N-atoms.

Mechanistic picture of the redox-neutral C C bond cleavage in 1,3-dilignol lignin model compound catalyzed by [Ru(Cl)(H)(PPh3)3]/triphos

2019 ◽  
Vol 471 ◽  
pp. 77-84 ◽  
Author(s):  
Xia Zhao ◽  
Yiying Yang ◽  
Rongxiu Zhu ◽  
Chengbu Liu ◽  
Dongju Zhang
Keyword(s):  
Model Compound ◽  
Bond Cleavage ◽  
Lignin Model Compound ◽  
Lignin Model

CC or CO Bond Cleavage in a Phenolic Lignin Model Compound: Selectivity Depends on Vanadium Catalyst

2012 ◽  
Vol 124 (14) ◽  
pp. 3466-3469 ◽  
Author(s):  
Susan K. Hanson ◽  
Ruilian Wu ◽  
Louis A. “Pete” Silks
Keyword(s):  
Model Compound ◽  
Bond Cleavage ◽  
Vanadium Catalyst ◽  
Lignin Model Compound ◽  
Lignin Model
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