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Poster Presentation 3-20
Characterization of the Molecular Weight Distribution of Oligomers from Batch Hydrolysis of Xylan
Xia Li, Alvin O. Converse, and Charles E. Wyman
Thayer School of Engineering, Dartmouth College 8000 Cummings Hall, Hanover, New Hampshire 03755
Telephone: (603) 646-1211; Fax: (603) 646-2277; E-mail: Xia.Li@Dartmouth.edu
We believe that xylose oligomers are important intermediates in hemicellulose hydrolysis, and experiments were conducted to provide new insight into their behavior. Xylan was treated with water in a batch reactor at selected temperatures and times to generate a liquid phase containing hemicellulose decomposition products (mainly xylooligosaccharides and xylose). Monomer and oligomer yields were then determined by measurement of xylose sugar concentrations by high performance liquid chromatography (HPLC) for the raw hydrolyzate and following post-hydrolysis of xylooligosaccharides to xylose, respectively. Next, intrinsic viscosity and the DNS assays were applied to measure the average molecular weight of the overall liquid. Gel permeation chromatography (GPC) was also used in conjunction with a fraction collector to separate the oligomers according to their molecular size, and DNS, intrinsic viscosity, and mass spectrometer tests were applied to each of these fractions to measure their molecular weight. Initial data will be reported to show the change in molecular weight distribution over time for hydrothermal xylan hydrolysis based on this approach. In addition, a model will also be presented to predict xylan and xylooligomer hydrolysis and xylose degradation based on this data.
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