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  • 1985-1989  (2)
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Year
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Wood science and technology 22 (1988), S. 167-175 
    ISSN: 1432-5225
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary Ezo spruce (Picea jezoensis) wood meal and milled wood lignin were successively reduced with sodium borohydride, methylated with methanol-HCl, oxidized with Fremy's salt, reduced with sodium dithionite, and methylated with diazomethane. Permanganate oxidation of the treated milled wood lignin showed that 0.08–0.1/C9 units of 3,4,5-trimethoxyphenyl groups were introduced into the softwood lignin. Although hardwood meal (beech, Fagus crenata) methylated with diazomethane gave a purple-red colour with the Mäule test, the treated softwood meal gave only a dark brown colour. The aromatic nuclei of lignin were broken down by the Mäule treatment. The consumption of permanganate by treated softwood lignin was higher than by hardwood lignin, which suggests that the guaiacyl nuclei were broken down severely. It is proposed that the purple-red colour obtained from methylated hardwood lignin with the Mäule colour test is generated by reaction of syringyl groups which were liberated by β-ether cleavage under the permanganate oxidation conditions.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Wood science and technology 22 (1988), S. 271-280 
    ISSN: 1432-5225
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary The acetyl bromide procedure for spectrophotometrically determining lignin in wood and wood pulp samples has been modified by adding perchloric acid to the digestion medium. This enables faster dissolution of the materials and the use of coarser samples. Subsequent treatment of the digestion mixtures with larger amounts of sodium hydroxide than those used in the conventional procedure has obviated the need for treatment with hydroxylamine. The modified method has been successfully applied to woodmeals and pulps from Pinus radiata and Eucalyptus species.
    Type of Medium: Electronic Resource
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