Lignins were isolated and purified from alkali treated prehydrolysate of corn stover. The paper presents the structural features of lignins in a series purification processes. Fourier transform infrared spectroscopy

ultraviolet-vis spectroscopy and proton nuclear magnetic resonance spectroscopy were used to analyze the chemical structure. Thermogravimetric analysis was applied to follow the thermal degradation

and wet chemical method was used to determine the sugar content. The results showed that the crude lignin from the prehydrolysate of corn stover was a heterogeneous material of syringyl

guaiacyl and p-hydroxyphenyl units

containing associated polysaccharides

lipids

and melted salts. Some of the crude lignin was chemically linked to hemicelluloses (mainly xylan). The lipids in crude lignin were probably composed of saturated and/or unsaturated long carbon chains

fatty acids

triterpenols

waxes

and derivatives of aromatic. The sugar content of purified lignin was less than 2.11%

mainly composed of guaiacyl units. DTG

max

of purified lignin was 359℃. The majority of the hydroxyl groups were phenolic hydroxyl groups. The main type of linkages in purified lignin was β-O-4. Other types of linkages included β-5

β-β and α-O-4.