scholarly journals On the factors affecting product distribution in laccase-catalyzed oxidation of a lignin model compound vanillyl alcohol: experimental and computational evaluation

2013 ◽  
Vol 11 (33) ◽  
pp. 5454 ◽  
Author(s):  
Maarit Lahtinen ◽  
Petri Heinonen ◽  
Mikko Oivanen ◽  
Pirkko Karhunen ◽  
Kristiina Kruus ◽  
...  
Keyword(s):  
Model Compound ◽  
Product Distribution ◽  
Vanillyl Alcohol ◽  
Factors Affecting ◽  
Lignin Model Compound ◽  
Computational Evaluation ◽  
Lignin Model ◽  
Catalyzed Oxidation

scholarly journals Difference in adsorbable organic halogen formation between phenolic and non-phenolic lignin model compounds in chlorine dioxide bleaching

2019 ◽  
Vol 6 (10) ◽  
pp. 191202
Author(s):  
Lisheng Shi ◽  
Jiayan Ge ◽  
Fuqiang Zhang ◽  
Shuangxi Nie ◽  
Chengrong Qin ◽  
...  
Keyword(s):  
Functional Groups ◽  
Chlorine Dioxide ◽  
Model Compound ◽  
Complex Structure ◽  
Chemical Properties ◽  
Phenolic Hydroxyl ◽  
Vanillyl Alcohol ◽  
Lignin Model Compound ◽  
Organic Halogen ◽  
Lignin Model

Adsorbable organic halogen (AOX) is generally formed by the reaction of residual lignin in pulps with chlorine dioxide during bleaching. Lignin has a complex structure. Different functional groups and bonds are present in lignin structures. Phenolic hydroxyl is one of the important functional groups in lignin, and it significantly influences the chemical properties and reactivity. To study the effect of phenolic hydroxyl on AOX formation, vanillyl alcohol (VA) was selected as the phenolic lignin model compound, and veratryl alcohol (VE) was selected as the non-phenolic lignin model compound in this study. The kinetics of AOX formation by the reaction of VA or VE with chlorine dioxide was studied. The effects of pH, chlorine dioxide, lignin model compound concentration and reaction temperature on AOX formation are discussed. The activation energies of the reaction of VA and VE with chlorine dioxide are 16 242.47 J mol −1 and 281.34 J mol −1 , respectively. Thus, we found that the non-phenolic lignin can react with chlorine dioxide to form AOX more easily than phenolic lignin.

Performance of cobalt titanate towards H2O2 based catalytic oxidation of lignin model compound

RSC Advances ◽  
2015 ◽  
Vol 5 (97) ◽  
pp. 79644-79653 ◽  
Author(s):  
Mariom Shilpy ◽  
Muhammad Ali Ehsan ◽  
Tammar Hussein Ali ◽  
Sharifah Bee Abd Hamid ◽  
Md. Eaqub Ali
Keyword(s):  
Liquid Phase ◽  
Catalytic Oxidation ◽  
Titanium Oxide ◽  
Model Compound ◽  
Solution Phase ◽  
Phase Method ◽  
Vanillyl Alcohol ◽  
Lignin Model Compound ◽  
Lignin Model ◽  
Solution Phase Method

Mixed metal cobalt titanium oxide (CoTiO3) prepared by solution phase method has been evaluated for the liquid phase catalytic oxidation of vanillyl alcohol to vanillin using H2O2 as an oxygen source.

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.

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 Exhaustive laccase-catalysed oxidation of a lignin model compound (vanillyl glycol) produces methanol and polymeric quinoid products

1985 ◽  
Vol 229 (1) ◽  
pp. 277-279 ◽  
Author(s):  
K Lundquist ◽  
P Kristersson
Keyword(s):  
Model Compound ◽  
Polymerization Process ◽  
Lignin Biodegradation ◽  
Simultaneous Formation ◽  
Initial Formation ◽  
Lignin Model Compound ◽  
Catalysed Oxidation ◽  
Visible Spectra ◽  
Lignin Model

Laccase-catalysed oxidation of the lignin-related phenol vanillyl glycol results in the initial formation of dimers and subsequent polymerization. The polymerization is accompanied by a liberation of methanol corresponding to 15-20% demethylation. Visible spectra together with reduction experiments suggest the simultaneous formation of o-quinones. The participation of quinone formation in the polymerization process and the possible role of such intermediates in lignin biodegradation is discussed.

scholarly journals Radicals from the gas-phase pyrolysis of a lignin model compound: p-coumaryl alcohol

RSC Advances ◽  
2016 ◽  
Vol 6 (67) ◽  
pp. 62399-62405 ◽  
Author(s):  
Meng-xia Xu ◽  
Lavrent Khachatryan ◽  
Alexander Baev ◽  
Rubik Asatryan
Keyword(s):  
Gas Phase ◽  
Model Compound ◽  
Lignin Model Compound ◽  
Lignin Model

The intermediate labile species – radicals produced in the gas-phase pyrolysis of p-coumaryl alcohol (p-CMA).

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