Search Results 1-9 of 9

  • Radical chain reactions in pyrolytic cleavage of the ether linkages of lignin model dimers and a trimer

    Watanabe Toshihiro , Kawamoto Haruo , Saka Shiro

    β-Ether-type dimers, [1-(4-hydroxy-3-methoxyphenyl)-2-(2-methoxyphenoxy)-1-propanol and 1-(3, 4-dimethoxyphenyl)-2-(2-methoxyphenoxy)-1-propanol], and an α, β-diether-type trimer [1-(4-(3, 4-dimethoxybenzyloxy)-3-methoxyphenyl) -2- (2-methoxyphenoxy) -1-propanol] were pyrolyzed in a closed ampoule reactor (N₂/250–400°C/2 min). …

    Holzforschung 63(4), 424-430, 2009-07-01


  • Pyrolytic cleavage mechanisms of lignin-ether linkages: A study on p-substituted dimers and trimers

    Kawamoto Haruo , Saka Shiro

    … Pyrolytic cleavage mechanisms of lignin-ether linkages were studied with some dimers and trimers which have various p-substituted Cα-phenoxy groups (-H, -OCH₃, -Cl or -COCH₃). … The α-ether-linkages in phenolic forms are cleaved in a heterolytic mechanism, while in non-phenolic forms the α-ether linkages are cleaved homolytically. …

    Holzforschung 62(1), 50-56, 2008-01


  • Effects of side-chain hydroxyl groups on pyrolytic β-ether cleavage of phenolic lignin model dimer

    KAWAMOTO Haruo , HORIGOSHI Sunao , SAKA Shiro

    … Effects of side chain hydroxyl groups on pyrolytic β-ether cleavage of phenolic model dimers were studied with various deoxygenated dimers under pyrolysis conditions of N₂/400°C/1 min. Although phenolic dimer with hydroxyl groups at the C α − and C γ −positions was much more reactive than the corresponding nonphenolic type, deoxygenation at the C γ -position substantially reduced the reactivity up to the level of the nonphenolic type. …

    Journal of wood science 53(3), 268-271, 2007-06-25

    IR  References (25)

  • Contribution of Syringyl β-O-4 Linkage in Different Hardwood Lignin Preparations

    堀 啓映子 , 清水 隆 , 飯塚 堯介

    … Sinapyl alcohol was confirmed as a major product of trimethylsilyl iodide (TMSiI) treatment of syringyl β-O-4 lignin model compound. … In this study, contribution of syringyl β-O-4 linkage in different lignin preparations was investigated by comparing the yields of sinapyl alcohol obtained by TMSiI treatment. … Periodate lignin of wood fiber was confirmed to be rich in syringyl β-O-4 because it gave higher yield of sinapyl alcohol than periodate lignin obtain from whole wood. …

    Bulletin of the Tokyo University Forests (112), 155-162, 2004-12


  • Selective Cleavage of β-ether Linkages in Lignin by TMSiI Treatment--Model experiment for guaiacyl dimer

    堀 啓映子 , 新谷 博幸 , 飯塚 堯介

    … Trimethylsilyl iodide (TMSiI) was known to cleave β-ether linkages in lignin under a very mild condition. … If a lignin fraction is formed by β-O-4 linkage exclusively, it should be cleaved into monomeric products by complete cleavage of β-O-4 linkage. …

    Bulletin of the Tokyo University Forests (112), 45-53, 2004-12


  • Reaction behavior of lignin in supercritical methanol as studied with lignin model compounds

    Minami Eiji , Kawamoto Haruo , Saka Shiro

    … In addition, 5-5, β-1, β-O-4, and α-O-4 types of dimeric lignin model compounds were used as representatives of linkages in lignin. … As a result, aromatic rings and 5-5 (biphenyl)-type structures were stable in supercritical methanol, and the β-1 linkage was not cleaved in the β-1-type structure but converted rapidly to stilbene. …

    Journal of Wood Science (49), 158-165, 2003-04


  • Effect of the Addition of Anthraquinone in Kraft Cooking  [in Japanese]

    SHINODA Yoshihiko , TOGAWA Eiji , TANAHASHI Mitsuhiko

    … 4) The delignification was accelerated with the cleavage of β-ether linkages of guaiacyl lignin by anthraquinone. …

    Research bulletin of the Faculty of Agriculture, Gifu University (55), p209-220, 1990-12


  • Acidolysis of bamboo lignin-2-Isolation and identification of acidolysis products

    NAKATSUBO F , TANAHASHI Mitsuhiko , HIGUCHI Takayoshi

    … Guaiacyl, syringyl and ρ-hydroxyphenyl monomers which are expected by cleavage of the β-ether bonds in arylglycerol-β aryl ether structures have been isolated and identified in the acidolysis products of a bamboo MWL by various methods such as IR and NMR spectrometry. …

    Wood Research (53), 9-18, 1972-08

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