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Updated: Jul 9, 2026

Quantitative 31P NMR Analysis of Lignins and Tannins
Published on: August 2, 2021
Monitoring of hydroxyl groups in wood during heat treatment using NIR spectroscopy
Katsuya Mitsui1, Tetsuya Inagaki, Satoru Tsuchikawa
1Gifu Prefectural Human Life Technology Research Institute, Yamada, Takayama 506-0058, Japan. mitsui@wood.rd.pref.gifu.jp
Abstract:
This paper deals with the evaluation of thermally treated wood by near-infrared (NIR) spectroscopy. In the NIR second derivative spectrum, the absorption band at 6913 cm(-1) appeared with the procession of heat treatment, which conclusively assigned to the phenolic hydroxyl groups due to the lignin in comparison with the spectrum of acetylated spruce wood. As a result of the changes in the ratio of the areal integral calculated from spectral separation in the region of hydroxyl groups (7200-6100 cm(-1)) by the Gauss-Newton method, it was clear that the degradation of hydroxyl group in the cellulose started predominantly from the amorphous region and followed to semicrystalline and crystalline region. There was an obvious correlation between the weight decrement of wood and the decrement of hydroxyl groups in the cellulose by heat treatment.
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