Ken-ichi Kuroda

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Dioxane lignin prepared from sago palm (Metroxylon sagu) was characterized by analytical pyrolysis coupled to gas chromatography-mass spectrometry. Large abundances of the p-hydroxybenzoates ester-linked to the lignin were proven by analytical pyrolysis as well as by mild alkaline treatment that produced p-hydroxybenzoic acid in 16.3% yield. Pyrolysis in(More)
With a view to visualizing the ultrastructural distribution of syringyl lignins in secondary plant cell walls, a polyclonal antibody raised from a synthetic DHP polymer consisting only of syringyl propane units was prepared. To test the reactivity of the antiserum, a mini-dot-blot immunoassay reducing the amounts of substrates and antiserum was developed. A(More)
The industrial production of palm oil concurrently generates a substantial amount of empty fruit bunch (EFB) fibers that could be used as a feedstock in a lignocellulose-based biorefinery. Lignin byproducts generated by this process may offer opportunities for the isolation of value-added products, such as p-hydroxybenzoate (pBz), to help offset operating(More)
A monoterpene and 15 diterpenes were isolated from the ethyl acetate extracts of the bark-glued resin from the resinous stem canker ofThujopsis dolabrata var.hondae Makino. A monoterpene (nezukone20) and 4 diterpenes (acetyl torulosol5, acetyl isocupressic acid8, acetyl abietinol11, and 7α-methoxytotarol18) were characteristic constituents of the ethyl(More)
Pyrolysis-gas chromatography in the presence of tetramethylammonium hydroxide (TMAH) was applied to the determination of the ratio of the abundances of the syringyl beta-aryl ether subunits to those of the guaiacyl equivalents (S/G) in lignin. Diazomethane-methylated kenafs (Hibiscus cannabinus and Hibiscus sabdariffa) and beech (Fagus crenata) in situ(More)
Lignin model compounds, synthetic lignins, and cedar wood have been analyzed by pyrolysis-gas chromatography(-mass spectrometry) in the presence of tetramethylammonium hydroxide (TMAH) to examine the behavior of beta-5 substructures specifically under these conditions. Two model compounds contained a beta-5 linkage and a gamma-CH2OH group. The phenolic(More)
Methyl esters of higher fatty acids were detected from the healthy bark of Thujopsis dolabrata var. hondae but not from the bark of the resinous stem canker of T. dolabrata var. hondae. This difference enabled us to distinguish healthy trees from diseased ones. Fourteen diterpenes were also isolated from the n-hexane extracts of the bark-glued resin taken(More)
The thermochemolytic behavior of 4-O-etherified cinnamyl alcohols and aldehydes in lignin was investigated in the presence of tetramethylammonium hydroxide (TMAH) (315 degrees C/4 s), using veratrylglycol-beta-(coniferyl alcohol) ether (1a), veratrylglycol-beta-(sinapyl alcohol) ether (1b), and veratrylglycol-beta-(coniferyl aldehyde) ether (2). The(More)
1,2-Diarylpropane-1,3-diol-type lignin model compounds, 1,2-bis(4-hydroxy-3-methoxyphenyl)propane-1,3-diol (1) and 1-(3,4-diethoxyphenyl)-2-(4-methoxyphenyl)propane-1,3-diol (2), were pyrolyzed at 500 degrees C for 4 s to clarify the thermal behavior of beta-1 subunits in lignin. Products were monitored by gas chromatography/mass spectrometry. The cleavage(More)