STRUCTURAL CHARACTERIZATION OF LIGNIN EXTRACTED WITH ALKALINE HYDROGEN PEROXIDE FROM FURFURAL RESIDUE

Py-GC/MS. Results showed that the yield of lignin increased with the increase of reaction time and temperature. The maximum lignin yield of 41.4% (corresponding to the original lignin) was achieved by extraction at 80 oC for 3 h. The average-molecular weight ( Mw) of the extracted lignins (780-850) was about 1/4 of that of the MWL (milled wood lignin) of furfural residue (2890), which indicated a severe degradation of furfural residue lignin under the treatment. Py-GC/MS analysis indicated that the major unit in lignins was p-hydroxycinnamyl (H), together with lower amounts of syringyl (S) and guaiacyl (G) units. The relative molar content of the H unit in the extracted lignins increased, as compared to MWL.