Soda lignins of raphia petiole have completely different structure from kraft lignins. Soda lignins have higher methoxyl content and fewer phenolic hydroxyl group. From nitro benzene oxidation, soda lignins have a higher percentage of syringaldhyde 18.20 and also a higher S/V molar ratio. This is the reason that soda lignin is composed mainly of syringyl units, while kraft lignin is composed of guaiacyl units. IR spectra show remarkable differences: soda lignins show the strongest bands at 1230#x2013;1330 cm#x2212;1, attributed to syringyl nucleus; whereas kraft lignins show the strongest bands at 1030 cm#x2212;1and 1270 cm#x2212;1, which are attributed to the guaiacyl nucleus. NMR spectra were also studied.
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