Insights about the effect of composition, branching and molecular weight on the slow pyrolysis of xylose-based polysaccharides

This work provides insights into the relationship between pyrolysis products distribution and structural features of xylose-based hemicelluloses. Three hemicelluloses differing in composition, molecular weight, chain branching origin were selected, structurally characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis nuclear magnetic resonance then used as feedstocks for slow tests up to 700 °C nitrogen environment. Commercial beechwood xylan was selected representative glucuronoxylan hemicellulose type, typical hardwood species. corncob it is composed a mixture low weight xylo-oligosaccharides with acetylation degree. In end, extracted from grape pruning, being an arabinoglucuronoxylan, chosen structure common most annual plants agricultural wastes. Low-branched material (corncob xylan) produced lowest yield char highest liquids, while highly-branched (grape pruning exhibited opposite trend. The liquid composition qualitatively similar all considered xylans. However, comparison quantifiable species showed different relative abundances. indicated that degree affected at higher extent feedstock pyrolytic behavior respect ash content.