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Acetylation of sugarcane bagasse hemicelluloses under mild reaction conditions by using NBS as a catalyst



Sugarcane bagasse hemicelluloses were partially acetylated with acetic anhydride using N-bromosuccinimide (NBS) as a catalyst under mild conditions in an almost solvent-free system. The overall yield and degree of substitution (DS) were varied from 66.2 and 83.5% and between 0.27 and 1.15, respectively, by changing the reaction temperature and duration. It was found that the yield and DS increased with reaction temperature from 18 to 80°C and reaction time between 0.5 and 5.0 h. The results showed that treatment of the native hemicelluloses with acetic anhydride using NBS as a catalyst conveniently provided the corresponding biopolymer esters. The products were characterized by FTIR, 13C-NMR spectroscopy, and thermal analysis. The new biopolymer acetates were thermally stable to over 200°C but underwent significant and rapid thermal degradation when heated above the onset of thermal degradation. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 53–61, 2004