Studies on electro-oxidation of lignin and lignin model compounds. Part 2: N-Hydroxyphthalimide (NHPI)-mediated indirect electro-oxidation of non-phenolic lignin model compounds
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Takumi Shiraishi
,
Toshiyuki Takano
Abstract
The N-hydroxyphthalimide (NHPI)-mediated indirect electro-oxidation of non-phenolic lignin model compounds has been investigated for selective Cα-carbonylation of lignin. A cyclic voltammogram of NHPI in 0.1 M LiClO4/CH3CN with 2,6-lutidine interpreted that NHPI can act as a mediator in the indicated process in the range 0.5–0.8 V vs. Ag/Ag+. The corresponding Cα-carbonyl compounds was obtained in high yields (85–97%) in the case of the monomer 1-(4-ethoxy-3-methoxyphenyl) ethanol in 0.1 M LiClO4/CH3CN or 0.1 M LiClO4/(CH3CN/H2O=7/3) with a small amount of 2,6-lutidine at 0.7 V vs. Ag/Ag+. The processing of the dimeric lignin model compound (4-ethoxy-3-methoxyphenylglycerol-β-guaiacyl ether) also gave the corresponding Cα-carbonyl compound in high yield (88–92%). The reaction proceeds through hydrogen atom transfer in the NHPI-mediated electro-oxidation. On the other hand, the direct electro-oxidation and indirect electro-oxidation mediated by ABTS [2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonate)] of the dimeric compound preferentially gave the corresponding Cα-Cβ cleavage product in low or moderate yields (5–40%). The conclusion is that NHPI is an excellent mediator for selective Cα-carbonylation of non-phenolic β-O-4 structures in lignin in electronic mediator system.
©2012 by Walter de Gruyter Berlin Boston
Articles in the same Issue
- Original Papers
- Refiner bleaching in a peroxide-based ATMP process compared with conventional bleaching
- Chemical characterization of polymerized products formed in the reactions of matairesinol and pinoresinol with the stable radical 2,2-diphenyl-1-picrylhydrazyl
- Characterization of MWLs from Tamarix ramosissima isolated before and after hydrothermal treatment by spectroscopical and wet chemical methods
- Studies on electrooxidation of lignin and lignin model compounds. Part 1: Direct electrooxidation of non-phenolic lignin model compounds
- Studies on electro-oxidation of lignin and lignin model compounds. Part 2: N-Hydroxyphthalimide (NHPI)-mediated indirect electro-oxidation of non-phenolic lignin model compounds
- Shaped hemocompatible aerogels from cellulose phosphates: preparation and properties
- The effects of combining guaiacol and syringol on their pyrolysis
- Multi-steps degradation method for β-O-4 linkage in lignins: γ-TTSA method. Part 1: Reaction of non-phenolic dimeric β-O-4 model compounds
- Optimization of Burkholderia sp. ZYB002 lipase production for pitch control in thermomechanical pulping (TMP) processes
- Evidence that release of internal stress contributes to drying strains of wood
- Structure of oak wood from the Swedish warship Vasa revealed by X-ray scattering and microtomography
- Physical properties of simul (red-silk cotton) wood (Bombax ceiba L.) chemically modified with styrene acrylonitrile co-polymer and nanoclay
- Characterisation of moisture-dependent plasticity of beech wood and its application to a multi-surface plasticity model
- Vibration method for grading of large cross-section coniferous timber species
- Ultrastructural evaluation of compression wood-like properties of common juniper (Juniperus communis L.)
- Effect of ammonia addition to alkaline copper quaternary wood preservative solution on the distribution of copper complexes and leaching
- Morphological responses of Betula protoplasts in fiber spinning
- Erratum
- Surface chemistry of vessel elements by FE-SEM, μ-XPS and ToF-SIMS
- Meetings
- Meetings
- Masthead
- 10.1515/hf-2012-masthead3
Articles in the same Issue
- Original Papers
- Refiner bleaching in a peroxide-based ATMP process compared with conventional bleaching
- Chemical characterization of polymerized products formed in the reactions of matairesinol and pinoresinol with the stable radical 2,2-diphenyl-1-picrylhydrazyl
- Characterization of MWLs from Tamarix ramosissima isolated before and after hydrothermal treatment by spectroscopical and wet chemical methods
- Studies on electrooxidation of lignin and lignin model compounds. Part 1: Direct electrooxidation of non-phenolic lignin model compounds
- Studies on electro-oxidation of lignin and lignin model compounds. Part 2: N-Hydroxyphthalimide (NHPI)-mediated indirect electro-oxidation of non-phenolic lignin model compounds
- Shaped hemocompatible aerogels from cellulose phosphates: preparation and properties
- The effects of combining guaiacol and syringol on their pyrolysis
- Multi-steps degradation method for β-O-4 linkage in lignins: γ-TTSA method. Part 1: Reaction of non-phenolic dimeric β-O-4 model compounds
- Optimization of Burkholderia sp. ZYB002 lipase production for pitch control in thermomechanical pulping (TMP) processes
- Evidence that release of internal stress contributes to drying strains of wood
- Structure of oak wood from the Swedish warship Vasa revealed by X-ray scattering and microtomography
- Physical properties of simul (red-silk cotton) wood (Bombax ceiba L.) chemically modified with styrene acrylonitrile co-polymer and nanoclay
- Characterisation of moisture-dependent plasticity of beech wood and its application to a multi-surface plasticity model
- Vibration method for grading of large cross-section coniferous timber species
- Ultrastructural evaluation of compression wood-like properties of common juniper (Juniperus communis L.)
- Effect of ammonia addition to alkaline copper quaternary wood preservative solution on the distribution of copper complexes and leaching
- Morphological responses of Betula protoplasts in fiber spinning
- Erratum
- Surface chemistry of vessel elements by FE-SEM, μ-XPS and ToF-SIMS
- Meetings
- Meetings
- Masthead
- 10.1515/hf-2012-masthead3
