Abstract
The conversion of lignocellulose to value-added products is normally focused on fuel production; however, large-scale biorefineries require a cost-effective pretreatment process that can effectively fractionate the three main constituents of lignocellulose for the production of chemicals, fuels, and materials. In this study, a hemicellulosic biopolymer from poplar was fractionated by a mild organosolv process and the effects of various chemicals (sodium hydroxide, triethylamine, and formic acid) and alcohols on the fractionation efficiency and structural variation of hemicellulose were examined. Comparative studies indicated that an acidic catalyst decreased the purity of hemicelluloses by partial degradation of cellulose, and the core of the hemicellulosic biomacromolecule could be released and dissolved under alkaline conditions with 5.8%~19.0% yields. In addition, the use of alcohol with longer alkyl chains facilitated the release of the hemicellulosic biomacromolecule by partially cleaving the ether bonds in the lignin-carbohydrate complex (LCC); this is probably due to steric hindrance. The thermal degradation behavior showed that complete pyrolysis was easily achieved for the hemicellulosic polymer with minimal branches irrespective of its molecular weight.
