ANALYSIS OF PHENOLIC GROUPS IN MODIFIED LIGNIN USING PROTON NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 1H -NMR
DOI:
https://doi.org/10.70169/VJFS.1332Keywords:
Hydromethylolation, lignin, formaldehyde, 1H-NMR, Hydromethylolation, lignin, formaldehyde, 1H-NMRAbstract
The phenolic groups in lignin were analyzed using Nuclear Magnetic Resonance ( -NMR) spectroscopy at a frequency of 500 MHz, performed on acetylated lignin samples dissolved in deuterochloroform ( ). Under modified conditions, the majority of signals from protons in phenolic hydroxyl groups were observed in the spectral range of . Analysis results showed that the phenolic group content in the original lignin reached approximately 0,24 ppm groups per phenylpropane unit. For modified lignin, the total number of phenolic groups was estimated to be 0,18 ppm groups per phenylpropane unit, with a distinct presence of guaiacyl ( ) and syringyl ( ) structural units. Among these, the proportion of phenolic groups belonging to guaiacyl units was recorded to be higher than that of syringyl units. The study confirms that combining NMR techniques provides a reliable method for elucidating structural modifications and evaluating the application potential of lignin in the production of adhesives and biomaterials.
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