Insights From Glucose Pyrolysis for Cellulose Pyrolysis

Experimental and predicted kinetics of glucose, the monomer of cellulose, provides quantitative and qualitative insights into the pyrolysis of cellulose. This finding is somewhat surprising, as the monomer does not have the β-1,4-glycosidic linkage between rings that is characteristic of cellulose. More recently, Mettler et al. [1] have reported thin-film pyrolysis data for glucose and cellulose oligomers that quantify how kinetics for glucose (with –OH groups instead of glycosidic linkages) differs from the oligomeric cellulose. However, our earlier work has shown that ab initio modeling of the pericyclic reactions of glucose’s C1-O-H group gives a transition state and rate constant that can be related to C1-O-R groups, where R is a hydrocarbon or alcohol group.

The present work describes comparison of the predictions with literature and new data on glucose pyrolysis. Pyrolysis in a thermogravimetric analyzer (TGA) identifies levoglucosan and other products of glucose pyrolysis. These results are then related to the work of Lin et al. [2], who used analyses by liquid chromatography to suggest that the cellulose chain decomposes by splitting into a cellulose-levoglucosan molecule (cellobiosan, -triosan, etc.) and a shortened cellulose chain.

Acknowledgments: This work was supported by RTI International, Research Triangle Park NC, under subcontract XCE-0-40622-01 from the Alliance for Sustainable Energy, LLC, manager and operator of the National Renewable Energy Laboratory, Golden CO.

References:

[1]  Mettler, M. S., Paulsen, A. D., Vlachos, D. G., Dauenhauer, P. J. The chain length effect in pyrolysis: bridging the gap between glucose and cellulose, Green Chemistry, 2012, DOI: 10.1039/C2GC35184F.

[2]  Lin, Y. C.; Cho, J.; Tompsett, G. A.; Westmoreland, P. R.; Huber, G. W. Kinetics and mechanism of cellulose pyrolysis. J. Phys. Chem. C 2009, 113, 20097–20107.