Effects of pretreatment temperature and alkali concentration on the composition of alkali-soluble lignins from wheat straw

✍ Scribed by Runcang Sun; J. Mark Lawther; W. B. Banks

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 554 KB
• Volume: 62
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(19961128)62:9<1473::aid-app17>3.0.co;2-#

✦ Synopsis

A new rapid method of two step precipitation for isolation of alkali-soluble lignins with relatively free of polysaccharides from wheat straw was proposed in this study. The isolated alkali-soluble lignin fractions LA contained rather low amounts of neutral sugars (0.7-1.0%) and had low average molecular weights (960-1440 Da). The isolated lignin fractions LA contained roughly equal amounts of guaiacyl (G) and syringyl ( S ) units with relatively fewer p-hydroxyphenyl (H) units, and appeared to be closely associated to phenolic acids and glucuronic acid or 4-0-methylglucuronic acid. The chemical compositions in each of the fractions are reported. The physico-chemical properties and structure features of these lignin fractions LA were characterized by UV-, IR-, '3C-NMR-spectroscopy, and alkaline nitrobenzene oxidation.