As the most abundant source of renewable aromatic compounds on the planet, lignin is an attractive feedstock for producing a range of chemicals and products that are currently derived from petroleum. Despite its great potential, separation of lignin depolymerization products remains one of the main obstacles toward cost-effective lignin valorization. Two lignin-rich streams, residues from enzymatic hydrolysis of the dilute acid and alkaline-pretreated corn stover, were depolymerized via pyrolysis using induction heating and catalytic transfer hydrogenolysis (CTH), respectively. Differences in phenolic compounds from gas chromatography-mass spectrometry and gel permeation chromatography analyses suggest that both pretreatment conditions and lignin depolymerization methods affected the product distribution. CTH lignin oils contain less polar compounds as compared to pyrolysis lignin oils, probably due to saturation of the derived compounds as a result of the reductive chemistry. The resulting liquid oils were subjected to sequential liquid-liquid extraction using a series of solvents with different polarities: hexane, petroleum ether, chloroform, and ethyl acetate. Sequential extraction fractionated lignin-derived oil into groups of different compounds depending on the solvent polarities. This study provides a better understanding of how the lignin source and processing method affect the depolymerization products and provides a possible way to fractionate lignin-derived compounds.
|Number of pages||9|
|Journal||Energy and Fuels|
|State||Published - May 16 2019|
Bibliographical noteFunding Information:
We acknowledge the National Science Foundation under OIA1355438 and OIA1632854 and the National Institute of Food and Agriculture, U.S. Department of Agriculture under accession number 1003563, and Hatch Program (#LAB94443) for supporting this work. The information reported in this paper is part of a project of the Kentucky and Louisiana Agricultural Experiment Stations (respectively) and in Louisiana with manuscript #2019-232-33449. We acknowledge Drs. Sue Nokes and Barbara Knutson for their insightful comments and guidance on this project. We thank NREL for providing the lignin samples.
© 2019 American Chemical Society.
ASJC Scopus subject areas
- Chemical Engineering (all)
- Fuel Technology
- Energy Engineering and Power Technology