Optimal lignin demethylation conditions were determined through demethylated lignin reactive activity toward formaldehyde

in terms of variation of catalyst

amount of catalyst

reaction temperature and reaction time.Lignin and its demethylated derivate product were characterized by semiquantitative FT-IR

GPC

and

1

H NMR.Results demonstrate that the content of methoxy group decreases from 0.990 to 0.765

and the content of phenolic hydroxyl group increases from 1.174 to 1.529 via semiquantitative FT-IR.GPC results indicate that macromolecular lignin degrades after demethylation

the content of M

w

below 2000 dramatically increases from 38% to 51%.

1

H NMR shows that alkyl chain breaks from benzene ring and β-O-4 linkages cleave and almost disappear after demethylateion.