Table 1 Quantification of the functional groups (mmol/g) in the lignins of PAL and PPAL using a quantitative 31P-NMR method.
From: Preparation and characterization of thermo-sensitive gel with phenolated alkali lignin
δ(ppm) | Assignment | PAL (mmol/g) | PPAL (mmol/g) |
|---|---|---|---|
145–148 | Aliphatic OH | 0.072 | 0.139 |
141.5–143 | Syringyl OH | 0.368 | 0.056 |
138.5–139.5 | Guaiacyl OH | 0.180 | 0.060 |
137–137.9 | p-Hydroxy phenyl OH | 0.012 | 0.369 |
133.4–135 | Carboxylic OH | 0.024 | 0.004 |
Active sitesa | 0.192 | 0.429 |
