[Study on the corn stover lignin oxidized by chlorine dioxide and modified by furfuryl alcohol].

ABSTRACT

The Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-Visible), nuclear magnetic resonance spectroscopy (1H NMR) and TG analysis were used to study the oxidation of corn stover lignin by chloride dioxide and subsequently modified by furfuryl alcohol. The results were as following The selective oxidation of lignin by chlorine dioxide was obtained by spectroscopy study. FTIR showed that the characteristic absorbance peaks of aromatic units were decreased after chloride dioxide oxidation. The increased absorbance for the band around 1720 cm(-1) corresponding to carbonyl stretching was achieved in the oxidized lignin and the lignin modified with furfuryl alcohol. The ultraviolet-visible spectroscopy showed that the absorbance around 280 nm was largely reduced after the lignin was oxidized. The 1H NMR spectroscopy also showed the decrease of aromatic units and methoxyl group in the oxidized lignin. All these indicated the formation of muconic acid and ester, or quinone derivatives when the lignin was selectively oxidized by chloride dioxide. The modification by furfuryl alcohol made the oxidized lignin more thermally stable.