Oxidation of a Lignin Model Compound by the Veratryl Alcohol Cation Radical. Results from Molecular Orbital Calculations

Holzforschung ◽  
1997 ◽  
Vol 51 (1) ◽  
pp. 47-56 ◽  
Author(s):  
Thomas Elder
Keyword(s):  
Molecular Orbital ◽  
Model Compound ◽  
Cation Radical ◽  
Veratryl Alcohol ◽  
Molecular Orbital Calculations ◽  
Lignin Model Compound ◽  
Lignin Model

Synthesis and application of Co(salen) complexes containing proximal imidazolium ionic liquid cores

2012 ◽  
Vol 90 (1) ◽  
pp. 60-70 ◽  
Author(s):  
Swapnil Sonar ◽  
Kenson Ambrose ◽  
Arthur D. Hendsbee ◽  
Jason D. Masuda ◽  
Robert D. Singer
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Model Compound ◽  
Veratryl Alcohol ◽  
Oxidation Catalysts ◽  
Imidazolium Ionic Liquid ◽  
Lignin Model Compound ◽  
Salen Complexes ◽  
Lignin Model ◽  
Salen Ligand

Ionic ligands derived from a salen ligand containing two proximal 1,3-disubstituted imidazolium ionic liquid cores form cobalt(III) complexes capable of selectively oxidizing veratryl alcohol, a lignin model compound, to veratraldehyde using air as the source of oxygen. These complexes are easy to prepare, inexpensive, water stable, and soluble in ionic liquids, making them viable candidates for use as oxidation catalysts.

scholarly journals Biomimetic Catalysts for Oxidation of Veratryl Alcohol, a Lignin Model Compound

Catalysts ◽  
2013 ◽  
Vol 3 (1) ◽  
pp. 232-246 ◽  
Author(s):  
Gustavo González-Riopedre ◽  
María Fernández-García ◽  
Esther Gómez-Fórneas ◽  
Marcelino Maneiro
Keyword(s):  
Model Compound ◽  
Veratryl Alcohol ◽  
Lignin Model Compound ◽  
Biomimetic Catalysts ◽  
Lignin Model

Keggin Type‐Polyoxometalate Decorated Ruthenium Nanoparticles: Highly Active and Selective Nanocatalyst for the Oxidation of Veratryl Alcohol as a Lignin Model Compound

2017 ◽  
Vol 2 (8) ◽  
pp. 2487-2494 ◽  
Author(s):  
Ismail Burak Baguc ◽  
Serif Saglam ◽  
Ilknur Efecan Ertas ◽  
Muhammed Nuri Keles ◽  
Metin Celebi ◽  
...  
Keyword(s):  
Model Compound ◽  
Veratryl Alcohol ◽  
Ruthenium Nanoparticles ◽  
Lignin Model Compound ◽  
Keggin Type ◽  
Highly Active ◽  
Lignin Model

Recyclable ionic liquid tagged Co(salen) catalysts for the oxidation of lignin model compounds

2013 ◽  
Vol 91 (12) ◽  
pp. 1258-1261 ◽  
Author(s):  
Kenson Ambrose ◽  
Bitu B. Hurisso ◽  
Robert D. Singer
Keyword(s):  
Ionic Liquid ◽  
Liquid Phase ◽  
Model Compound ◽  
Veratryl Alcohol ◽  
Pure Oxygen ◽  
Model Compounds ◽  
Imidazolium Ionic Liquid ◽  
Lignin Model Compounds ◽  
Lignin Model Compound ◽  
Lignin Model

Ionic liquid tagged salen ligands containing two proximal 1,3-disubstituted imidazolium ionic liquid cores form cobalt(III) complexes capable of selectively oxidizing veratryl alcohol, a lignin model compound, to veratraldehyde using air or pure oxygen as the source of oxygen. Entrainment of these catalysts in either 1-butyl-3-methylimidazolium hexafluorophosphate, [bmim][PF6], or 1-butyl-3-methylimidazolium bistriflimide, [bmim][NTf2], hydrophobic ionic liquid solvents, results in biphasic reactions when water is used as the second solvent allowing the catalyst/ionic liquid phase to be recycled.

Dihydroxybenzenes: driven Fenton reactions

2001 ◽  
Vol 44 (5) ◽  
pp. 251-256 ◽  
Author(s):  
J. Rodríguez ◽  
C. Parra ◽  
D. Contreras ◽  
J. Freer ◽  
J. Baeza
Keyword(s):  
Fenton Reaction ◽  
Model Compound ◽  
Molecular Mass Distribution ◽  
Veratryl Alcohol ◽  
Oxidation Potential ◽  
Dihydroxybenzoic Acid ◽  
Pulp Bleaching ◽  
Lignin Model Compound ◽  
Cellulose Pulp ◽  
Lignin Model

Different compounds that reduce Fe(III) and that simultaneously increase the oxidation potential of the H2O2/Fe2+ system, have been evaluated. In this work, the improving of Fenton reactions by 2,3-dihydroxybenzoic acid (2,3-DHBA), 3,4-dihydroxybenzoic acid (3,4-DHBA) or 1,2-dihydroxybenzene (CAT) were studied. The three compounds are able to reduce Fe(III) to Fe(II), but the kinetic results depend on the method used to determine the Fe(II) ion. The dihydroxybenzenes (DHBs) degrades veratryl alcohol (VA), a lignin model compound, to a greater extent than observed in a typical Fenton reaction. The rate of VA degradation was associated with the duration of the chemiluminescence (CAT > 2,3-DHBA > 3,4-DHBA) and not with the sum of integrated counts. The treatment of a cellulose pulp bleaching effluent with DHBs/Fe(III)/H2O2 was evaluated by analyzing their depolymerization at pH 4 and 7 through molecular mass distribution determinations.

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.

scholarly journals Model compounds-based study on adsorption and dispersion properties of lignin-based superplasticizer

2021 ◽  
Vol 104 (1) ◽  
pp. 003685042098062
Author(s):  
Shuangping Ma ◽  
Qingjun Ding ◽  
Fen Zhou ◽  
Huaxiong Zhu
Keyword(s):  
Molecular Structure ◽  
Zeta Potential ◽  
Model Compound ◽  
Research Work ◽  
Structure Activity Relationship ◽  
Activity Relationship ◽  
Lignin Model Compound ◽  
Structure Activity ◽  
Lignin Model ◽  
Relationship Of

The chemical modifications of lignin-based superplasticizers have attracted extensive attentions during recent years. The comprehending of the structure-activity relationship of lignin-based superplasticizer is important to promote the modification and application research of lignin resources. However, lignin features complex and variable molecular structure, which is not conducive to study on structure-activity relationship of lignin-based superplasticizer as well as development and application of new lignin-based superplasticizer. However, the related research work can be simplified by selecting small molecular compound with appropriate molecular structure as the lignin model compound. This article intends to study the structure-activity relationship of lignin-based superplasticizer by using dihydroeugenol as the lignin model compound. Through the substitution of lignin by dihydroeugenol during the synthesis process, a model compound lignin-based superplasticizer (DAFS) was synthesized. The adsorption and dispersion properties of this superplasticizer and reference sample (LAFS) were investigated by fluidity test, Zeta-potential measurement, Total organic carbon analysis and others. The results suggest that the adsorption behavior of both DAFS and LAFS conformed to the Langmuir isotherms and Pseudo-second order kinetic. In cement paste, added with 1 g/L of LAFS and DAFS, Zeta potential were reduced from +3.5 to −15.2 mV and −18.7 mV, respectively. The substitution of lignin by dihydroeugenol has no significantly influence on the dispersive property, but differences on rheological properties which need to be optimized in the future. All the tests confirmed that dihydroeugenol is suitable to replace lignin on exploring the structure-activity relationship of lignin-based superplasticizer. This research work provides new insight on model study of lignin-based superplasticizer.

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