Iron porphyrin catalyzed oxidation of lignin model compounds: the oxidation of veratryl alcohol and veratryl acetate

1992 ◽  
Vol 70 (8) ◽  
pp. 2314-2318 ◽  
Author(s):  
Futong Cui ◽  
David Dolphin
Keyword(s):  
Aqueous Solution ◽  
Veratryl Alcohol ◽  
Cleavage Product ◽  
Iron Chloride ◽  
Ring Cleavage ◽  
Model Compounds ◽  
Lignin Model ◽  
Mechanism Of Oxidation ◽  
Catalyzed Oxidation ◽  
Insight Into

meso-Tetra(2,6-dichloro-3-sulfonatophenyl)porphyrin iron chloride catalyzes the oxidation of 3,4-dimethoxybenzyl alcohol (veratryl alcohol) in aqueous solution to give veratraldehyde along with demethoxylation and ring-cleavage products. The isolation of a direct ring-cleavage product from the oxidation of veratryl acetate in aqueous solution supports the previously proposed ring-cleavage mechanisms. The oxidation in methanol, however, does not lead to ring-cleavage products. When veratryl alcohol was oxidized in methanol, solvent was found to be incorporated into the 3-position of veratryl alcohol, giving new insight into the mechanism of oxidation.

Iron porphyrin catalyzed oxidation of lignin model compounds: oxidation of phenylpropane and phenylpropene model compounds

1995 ◽  
Vol 73 (12) ◽  
pp. 2153-2157 ◽  
Author(s):  
Futong Cui ◽  
David Dolphin
Keyword(s):  
Iron Chloride ◽  
Ring Cleavage ◽  
Iron Porphyrin ◽  
Model Compounds ◽  
Lignin Model Compounds ◽  
Aqueous Acetonitrile ◽  
Tert Butylhydroperoxide ◽  
Lignin Model ◽  
Aromatic Ring Cleavage ◽  
Catalyzed Oxidation

The oxidation of 1-(4-ethoxy-3-methoxyphenyl)propane (2) and 1-(4-ethoxy-3-methoxyphenyl)propene (3) by meso-tetra(2,6-dichloro-3-sulphonatophenyl)porphyrin iron chloride (TDCSPPFeCl, 1) and tert-butylhydroperoxide (t-BuOOH) are discussed. In addition to a Cα-hydroxylation product, demethoxylation and direct aromatic ring cleavage products were found in the oxidation of 2. When 3 was oxidized by 1 and t-BuOOH in aqueous acetonitrile, an acetonitrile-incorporated product was found. A mechanism for the oxidation of 3 is proposed. Keywords: lignin, ligninase, iron porphyrin, model, degradation.

Phenolic mediators enhance the manganese peroxidase catalyzed oxidation of recalcitrant lignin model compounds and synthetic lignin

2014 ◽  
Vol 72 ◽  
pp. 137-149 ◽  
Author(s):  
Paula Nousiainen ◽  
Jussi Kontro ◽  
Helmiina Manner ◽  
Annele Hatakka ◽  
Jussi Sipilä
Keyword(s):  
Manganese Peroxidase ◽  
Model Compounds ◽  
Lignin Model Compounds ◽  
Lignin Model ◽  
Catalyzed Oxidation

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 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.

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