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Product profiles in enzymic and non-enzymic oxidations of the lignin model compound erythro-1-(3,4-dimethoxyphenyl)-2-(2-methoxyphenoxy)-1,3-propanediol

Christina Bohlin ; Per Persson ; Lo Gorton ; Knut Lundquist (Institutionen för kemi- och bioteknik, Skogsindustriell kemiteknik) ; Leif Jönsson
Journal of Molecular Catalysis B: Enzymatic (1381-1177). Vol. 35 (2005), 4-6, p. 100-107.
[Artikel, refereegranskad vetenskaplig]

The erythro form of the lignin model compound 1-(3,4-dimethoxyphenyl)-2-(2-methoxyphenoxy)-1,3-propanediol (1) was oxidized with laccase/ABTS, lead(IV) tetraacetate (LTA), lignin peroxidase/H2O2, cerium(IV) ammonium nitrate (CAN) and Fenton's reagent. The product profiles obtained with the different oxidants were compared after separation, identification and quantification of the products using HPLC, UV-diode array detector and electrospray ionization mass spectrometry in positive ionization mode. The oxidants generated different product profiles that reflected their different properties. Oxidation with laccase/ABTS resulted almost exclusively in formation of 1-(3,4-dimethoxyphenyl)-3-hydroxy-2-(2-methoxyphenoxy)-1-propanone (2). Oxidation with LTA resulted in more 3,4-dimethoxybenzaldehyde (3) than ketone 2. Lignin peroxidase and CAN gave similar product profiles and aldehyde 3 was the predominant product (only small amounts of ketone 2 were formed). Oxidation with Fenton's reagent resulted in the formation of more aldehyde 3 than ketone 2 but the yields were very low. CAN served as an excellent model for the lignin peroxidase-catalyzed oxidation, while the laccase-mediator system, LTA and Fenton's reagent provided distinctly different product profiles. Erythro-1-(3,4-dimethoxyphenyl)-1,2,3-propanetriol was present among the products obtained on oxidation with LTA, lignin peroxidase, CAN and Fenton's reagent. The differences in redox potential between the oxidants afford an explanation of the diverse product patterns but other factors may also be of importance. The reactions leading to cleavage of the β-ether bond with formation of 1-(3,4-dimethoxyphenyl)-1,2,3-propanetriol (veratrylglycerol) were found to proceed without affecting the configuration at the β-carbon atom.

Nyckelord: 1-(3,4-Dimethoxyphenyl)-2-(2-methoxyphenoxy)-1,3-propanediol, Lignin degradation, Laccase, Lignin peroxidase, Non-enzymic oxidants



Denna post skapades 2006-08-25. Senast ändrad 2013-06-03.
CPL Pubid: 11389

 

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Institutioner (Chalmers)

Institutionen för kemi- och bioteknik, Skogsindustriell kemiteknik (2005-2014)

Ämnesområden

Bioorganisk kemi
Molekylärbiologi

Chalmers infrastruktur