Analysis and Characterization of Acetylated Sugarcane Bagasse Hemicelluloses

Abstract

ABSTRACT Acetylation of sugarcane bagasse hemicelluloses with acetic anhydride using N-bromosuccinimide (NBS) as a catalyst in N,N-dimethylformamide/lithium chloride system under mild conditions was comparatively studied. The yield and the degree of substitution (DS) ranged from 68.2% and 0.37 to 78.6% and 0.82 as a function of experiment conditions. It was found that the yield and DS increased with N-bromosuccinimide concentration between 0.5 and 1.0%, reaction temperature from 18 to 80°C, and reaction time between 2 and 4 h. In comparison, other catalysts such as H2SO4 and four tertiary amine catalysts, pyridine, 4-dimethylaminopyridine, N-methyl pyrrolidine, and N-methyl pyrrolidinone, were also investigated. The results showed that NBS can be used as a novel and effective catalyst for acetylation of hemicelluloses under extremely mild reaction conditions. The new polymeric products were characterized by FT-IR, 13C NMR spectroscopy, and thermal analysis. The thermal stability of the material was increased by chemical modification.