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Coconut husk lignin. II. Characterization by infrared and nuclear magnetic resonance spectroscopy
Author(s) -
VázquezTorres H.,
CanchéEscamilla G.,
CruzRamos C. A.
Publication year - 1992
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1992.070450411
Subject(s) - lignin , sodium hydroxide , husk , organosolv , chemistry , nuclear chemistry , anthraquinone , infrared spectroscopy , nuclear magnetic resonance spectroscopy , hardwood , extraction (chemistry) , proton nmr , potassium hydroxide , carbon 13 nmr , softwood , organic chemistry , materials science , botany , composite material , biology
Results of the characterization of coconut husk lignin by infrared (IR) and proton nuclear magnetic resonance (H‐NMR) spectroscopy are presented. Lignin was extracted with both alkaline and organosolv liquors. The IR spectra of dioxane lignin were very similar to those reported for hardwood lignins. Furthermore, these results combined with those obtained from the H‐NMR studies suggest that coconut husk lignin can be classified into the Lm‐type lignins. These lignins are characteristic of the monocotyledon class, of which the coconut palm is a member. The H‐NMR studies showed that anthraquinone significantly inhibited the occurrence of lignin condensation during the alkaline extraction with sodium hydroxide solutions. This inhibition was more intense in the lignin extracted at 150°C than in that extracted at 100°C.