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. 2016 Oct 18;9:217. doi: 10.1186/s13068-016-0632-9

Table 4.

Quantification of the functional groups (mmol/g) by quantitative 31P-NMR in the alkali lignins obtained by the integrated process

Lignin fractions Aliphatic OH Syringyl OH Guaiacyl OH H + P−OH Carboxylic group Total phenolic OH
C NC C NC
AL 2.72 0.02 0.12 0.07 0.35 0.16 0.86 0.72
L(100-0.5-2) 1.56 0.11 0.34 0.20 0.59 0.31 0.93 1.55
L(130-0.5-2) 1.40 0.16 0.34 0.21 0.60 0.35 0.93 1.66
L(150-0.5-2) 1.39 0.17 0.35 0.22 0.60 0.37 1.01 1.71
L(130-0.5-0.5) 1.45 0.11 0.31 0.19 0.57 0.34 0.93 1.52
L(130-0.5-3) 1.39 0.19 0.36 0.22 0.62 0.37 0.97 1.76
L(130-0.25-2) 1.47 0.18 0.32 0.19 0.60 0.32 0.88 1.61
L(130-1-2) 1.37 0.20 0.37 0.26 0.68 0.42 1.06 1.93

C condensed; NC non-condensed; H + POH the total content of p-hydroxyphenyl OH and free p-coumaric acid