Comparison studies between soda lignin and soda-anthraquinone lignin in terms of physico-chemical properties and structural features

Abstract

Soda lignin and soda anthraquinone lignin were compared in this study. The physico-chemical properties and structural features of the isolated lignin were characterized by Fourier Transform Infrared Spectrophotometry (FTIR), Ultraviolet (UV), ash test, Carbon-Hydrogen-Nitrogen (CHN) analyzer, Nuclear Magnetic Resonance (13C-NMR) and High Performance Liquid Chromatography (HPLC). Nitrobenzene oxidation was performed towards these two types of lignin especially for the HPLC analysis. Based on the CHN, 13C-NMR and UV results there were no significant differences between soda lignin and soda anthraquinone lignin. The FTIR results also showed that there is no significant differences in terms of functional groups that exist in both lignin. HPLC results, however, identified slight difference in the ratio of monomers present in the lignin samples with the soda lignin having 1:5:4 ratio of S:V:H and for soda anthraquinone lignin was 1:5:2. © 2006 Asian Network for Scientific Information.