The self-condensation reactions of the lignin model compounds, vanillyl and veratryl alcohol

1980 ◽  
Vol 33 (4) ◽  
pp. 917 ◽  
Author(s):  
JA Hemmingson ◽  
G Leary
Keyword(s):  
Cell Wall ◽  
Plant Cell ◽  
Plant Cell Wall ◽  
Veratryl Alcohol ◽  
The Self ◽  
Benzyl Ether ◽  
Model Compounds ◽  
Lignin Model Compounds ◽  
Condensation Reactions ◽  
Lignin Model

Self-condensation of the lignin model compounds vanillyl and veratryl alcohol leads to the formation of benzyl ether and diphenylmethane structures. It is suggested that these structures may be formed within lignin as it ages in the plant cell wall.

Lignin Utilization I. Kinetics of Base-Catalyzed Condensation Reactions of Lignin Model Compounds

1972 ◽  
Vol 2 (3) ◽  
pp. 271-275 ◽  
Author(s):  
G. E. Troughton ◽  
J. F. Manville
Keyword(s):  
Condensation Reaction ◽  
Activation Energies ◽  
The Self ◽  
Model Compounds ◽  
Lignin Model Compounds ◽  
Temperature Range ◽  
Condensation Reactions ◽  
Lignin Model ◽  
Lignin Utilization ◽  
Kinetics Of

Rates of formation were measured for the base-catalyzed condensation reactions occurring between 4-alkylguaiacol compounds and their 6-methylol derivatives over the temperature range 85.5–100 °C. It was found that both the intercondensation reaction between the 4-alkylguaiacol compound and its 6-methylol derivative and the self-condensation reaction of the latter compound occurred at significant rates. In the 4-propylguaiacol – 4-methyl-6-methylolguaiacol system, the above two condensation reactions occurring in this system had the same activation energies, 35 kcal/mol. Similarly, in the 4-methylguaiacol – 4-propyl-6-methylolguaiacol system these two condensation reactions had equivalent activation energies, but slightly lower than in the former system, 32 kcal/mol. The kinetic results found for the model guaiacol compounds in this study demonstrate the possibility that a lignin-derived compound having more than one reactive position can be developed into a phenolic-type resin.

A New Way of Forming Lignin-Carbohydrate Bonds. Etherification of Model Benzyl Alcohols in Alcohol/ Water Mixtures

1979 ◽  
Vol 32 (1) ◽  
pp. 225 ◽  
Author(s):  
JA Hemmingson
Keyword(s):  
Cell Wall ◽  
Plant Cell ◽  
Plant Cell Wall ◽  
Veratryl Alcohol ◽  
Vanillyl Alcohol ◽  
Benzyl Alcohols ◽  
Alcohol Water ◽  
Hydroxybenzyl Alcohol

The etherification reactions of vanillyl alcohol and veratryl alcohol in alcohol/water mixtures have been studied. It is concluded that lignin-carbohydrate bonds could be formed subsequent to lignification of the plant cell wall, through etherification of the p-hydroxybenzyl alcohol structures in the lignin polymer.

Lignin Degradation in Oxygen Delignification Catalysed by [PMo7V5O40]8- Polyanion. Part II. Study on Lignin Monomeric Model Compounds

Holzforschung ◽  
2000 ◽  
Vol 54 (5) ◽  
pp. 511-518 ◽  
Author(s):  
D.V. Evtuguin ◽  
C. Pascoal Neto ◽  
H. Carapuça ◽  
J. Soares
Keyword(s):  
Reaction System ◽  
Veratryl Alcohol ◽  
Vanillyl Alcohol ◽  
Coupling Reactions ◽  
Reaction Products ◽  
Oxygen Delignification ◽  
Model Compounds ◽  
Lignin Model Compounds ◽  
Lignin Oxidation ◽  
Lignin Model

Summary Vanillyl and veratryl alcohols were used as monomeric lignin model compounds in experiments aiming to enhance the understanding of the lignin oxidation mechanisms involved in the oxygen delignification in acidic media catalysed by [PMo7V5O40]8− (HPA-5) heteropolyanion. Based on the model compound experiments, the first step of lignin oxidation is suggested to be a one-electron oxidation by the catalyst. This step is followed by coupling reactions and/or by further oxidation by the catalyst. The ratio of coupling/oxidation reaction products depends on the oxidation conditions and decreases with temperature raise. The higher oxidation rate of vanillyl alcohol as compared to the veratryl alcohol in the reaction system O2/HPA-5 was explained by the redox properties of the catalyst. The insufficiently high redox potential of HPA-5 did not allow the efficient oxidation of veratryl alcohol. The former was oxidised by VO2 + ions dissociated from the HPA-5 under the acidic conditions. The reactivity of different lignin structural units in the reaction system O2/HPA-5 was estimated by electrochemical methods using various lignin model compounds.

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.

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