Pyrolysis Kinetics for Small-Molecule Intermediates of Cellulose Pyrolysis

Pyrolysis experiments on glycolaldehyde, glyceraldehyde, and 1,3-dihydroxyacetone reveal products that provide new insights into biomass pyrolysis chemistry. Pyrolysis starting from these small molecules helps in constructing a reliable reaction mechanism that can clarify the details of cellulose pyrolysis (1-4). The compounds studied here appear in glucose and cellulose pyrolysis; therefore, the research gives some detail on secondary reactions that happen in the gas phase once volatile compounds start to form from glucose and cellulose pyrolysis.

In this work, flash pyrolysis was conducted (CDS Analytical, Pyroprobe® Model 5200) with analysis by comprehensive two-dimensional gas chromatography-mass spectrometry (LECO Corp., Pegasus® 4D GCxGC-TOFMS), supplemented by computational quantum chemistry for theoretically predicting products that may be formed from the pyrolysis. The pyrolysis was conducted at different temperatures so that the formation temperature of different species can be mapped. The detailed temperature-resolved measurement can help in identifying optimal temperature of operation under real pyrolysis conditions. Initial results showed both decomposition and molecular-weight growth in the cases of glyceraldehyde and 1,3-dihydroxyacetone. Considerable isomerization between glyceraldehyde and 1,3-dihydroxyacetone was also observed. No reaction of glycolaldehyde was detected at the flash-pyrolysis conditions.

References

1. Vikram Seshadri and Phillip R. Westmoreland, “Concerted reactions and mechanism of glucose pyrolysis and implications for cellulose kinetics,” J. Phys. Chem. A, 116 (2012) 11997-12013.
2. Heather B. Mayes and Linda J. Broadbelt, “Unraveling the reactions that unravel cellulose,” J. Phys. Chem. A, 116 (2012) 7098-7106.
3. Rajeev S. Assary and Larry A. Curtiss, “Thermochemistry and Reaction Barriers for the Formation of Levoglucosenone from Cellobiose,” ChemCatChem, 4(2) (2012) 200-205.
4. Vishal Agarwal, Paul J. Dauenhauer, George W. Huber, Scott M. Auerbach, “Ab Initio Dynamics of Cellulose Pyrolysis: Nascent Decomposition Pathways at 327 and 600 °C,” J. Am. Chem. Soc., 134 (2012) 14958−14972.

Contact Information

Vikram Seshadri

vseshad@ncsu.edu

Department of Chemical and Biomolecular Engineering

North Carolina State University

Box 7905

Raleigh, NC  27695-7905

Patrick Fahey

pjfahey@ncsu.edu

Department of Chemical and Biomolecular Engineering

North Carolina State University

Box 7905

Raleigh, NC  27695-7905

Xinglian Geng

xgeng@ncsu.edu

Department of Chemical and Biomolecular Engineering

North Carolina State University

Box 7905

Raleigh, NC  27695-7905

Phillip R. Westmoreland*

prwestmo@ncsu.edu

Executive Director, Institute for Computational Science and Engineering

Professor, Department of Chemical and Biomolecular Engineering

North Carolina State University

Box 7905

Raleigh, NC  27695-7905

*To whom correspondence should be addressed.