Synergetic effect of dilute acid and alkali treatments on fractional application of rice straw

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
Lignin fractions	Aliphatic OH	C	NC	C	NC	H + P−OH	Carboxylic group	Total phenolic OH
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 + P−OH the total content of p-hydroxyphenyl OH and free p-coumaric acid

ISSN: 2731-3654