Structural characterization of lignins isolated from Caragana sinica using FT-IR and NMR spectroscopy

Ling-Ping Xiao1, Zheng-Jun Shi, Feng Xu

  • 1College of Material Science and Technology, Beijing Forestry University, Beijing 100083, China. lingpingxiao@gmail.com

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IR spectra are divided into two main regions: the diagnostic region and the fingerprint region. The diagnostic region of the spectrum lies above 1500 cm−1. The absorptions resulting from single-bond vibrations of the N–H, C–H, and O–H stretch at higher wavenumbers and appear on the left side of the spectrum. The stretching absorptions of the C≡C and C≡N occur between 2100–2300 cm−1. In contrast, those arising from stretching absorptions of the C=O, C=N, and C=C occur between 1600–1850 cm−1.
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