Exploring Alkyl-O-Alkyl Ether Structures in Softwood Milled Wood Lignins.
In: Journal of agricultural and food chemistry, Jg. 71 (2023-01-11), Heft 1, S. 580-591
Online
academicJournal
Zugriff:
Recent studies have suggested that there are significant amounts of various alkyl ether (Alk-O-Alk; Alk = alkyl) moieties in a spruce native lignin preparation, milled wood lignin (SMWL). However, the comprehensive NMR assignment to these moieties has not been addressed yet. This study focused on investigating different types of Alk-O-Alk structures at the α- and γ-positions of the lignin side chain in an heteronuclear single-quantum coherence (HSQC) spectrum of SMWL using experimental NMR data of lignin and synthesized model compounds. Ambiguous structural features were predicted by computer simulation of 1 H and 13 C NMR spectra to complement the experimental NMR data. As a result, specific regions in the HSQC spectrum were attributed to different Alk-O-Alk moieties of Alk-O-Alk/β-O-4 and Alk-O-Alk/β-β' structures. However, the differences between the specific regions were rather subtle; they were not well separated from each other and some major lignin moieties. Furthermore, SMWL contained a large variety of Alk-O-Alk moieties but in minute individual amounts, resulting in rather broad, superimposing resonances. Thus, evaluation did not allow assigning individual types of Alk-O-Alk moieties from the HSQC spectra; instead, they were quantified as total (α- and γ-linked) Alk-O-Alk based on the balance of structural units in the 13 C NMR spectra. At last, potential formation mechanisms of various Alk-O-Alk ether structures in lignin biosynthesis, lignin aging, and during ball milling of wood were hypothesized and discussed.
Titel: |
Exploring Alkyl-O-Alkyl Ether Structures in Softwood Milled Wood Lignins.
|
---|---|
Autor/in / Beteiligte Person: | Zhu, X ; Sipilä, J ; Potthast, A ; Rosenau, T ; Balakshin, M |
Link: | |
Zeitschrift: | Journal of agricultural and food chemistry, Jg. 71 (2023-01-11), Heft 1, S. 580-591 |
Veröffentlichung: | Washington, American Chemical Society., 2023 |
Medientyp: | academicJournal |
ISSN: | 1520-5118 (electronic) |
DOI: | 10.1021/acs.jafc.2c06375 |
Schlagwort: |
|
Sonstiges: |
|