Review Article
Structural Characterization of Lignin and Its Degradation Products with Spectroscopic Methods
Table 5
Assignments of signals in
31P NMR spectrum to hydroxyl groups in lignin [
29,
82].
| Chemical shift/ppm | Structural assignments |
| 145.5–150.0 | Aliphatic -OH | 136.5–144.7 | Phenols | 140.0–144.5 | C5 substituted | 143.5 | β-5 | 142.7 | Syringyl | 142.3 | 4-O-5 | 141.2 | 5–5 | 139.0–140.0 | Guaiacyl | 138.2–139.0 | Catechol | 137.3–138.2 | p-Hydroxyphenyl | 133.6–136.6 | Carboxylic acid -OH |
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