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