Operando spectroscopic studies of solvo-catalytic lignin disassembly
EMSL Project ID
49121
Abstract
Lignocellulosic biomass represents an abundant and renewable resource that could displace a significant amount of the nation’s petroleum, but its widespread utilization will require the development of more efficient and effective conversion processes. Currently, only the polysaccharide components of plant biomass are valorized, while the non-polysaccharide fraction (i.e., lignin, an aromatic macromolecule) is largely wasted. Economic viability requires conversion of the entire biomass, to produce not only commodity fuels and chemicals, but also value-added products (e.g., fine chemicals and performance materials). Lignin is a new and sustainable source of aromatic compounds. The high molecular weight and the recalcitrant structure of lignin require reaction conditions (above 200 °C and 80 bar) that make it difficult to obtain a molecular-level understanding of reaction networks through operando studies of the catalyst system. We will use solid-state NMR spectroscopy with unique EMSL-built high temperature/pressure rotors for in situ mechanistic and kinetic analyses of reactions involving lignin and lignin model compounds. We will use 13C-enriched lignin and lignocellulose for real-time quantification of reaction intermediates, monitoring the temporal evolution of molecular species in coexisting solid, liquid, and gas phases. Operando EPR spectroscopy at high T/P will provide information about catalyst transformations involving paramagnetic metals, specifically, oxidation state and aggregation of Cu and Ni during the course of the reaction. The combination of NMR and EPR will provide comprehensive information about the activation and selectivity of the catalyst, the participation of the solvent system, and the evolution of the lignin structure.
Project Details
Project type
Exploratory Research
Start Date
2015-10-15
End Date
2016-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Chamas A., L. Qi, H.S. Mehta, J.A. Sears, S.L. Scott, E.D. Walter, and D.W. Hoyt. 2019. "High Temperature/Pressure MAS-NMR for the Study of Dynamic Processes in Mixed Phase Systems." Magnetic Resonance Imaging 56. PNNL-SA-138048. doi:10.1016/j.mri.2018.09.026
Qi L., A. Chamas, Z.R. Jones, E.D. Walter, D.W. Hoyt, N.M. Washton, and S.L. Scott. 2019. "Unraveling the Dynamic Network in the Reactions of an Alkyl Aryl Ether Catalyzed by Ni/y-Al2O3 in 2-Propanol." Journal of the American Chemical Society 141, no. 43:17370-17381. PNNL-SA-148402. doi:10.1021/jacs.9b09071
Walter E.D., L. Qi, A. Chamas, H.S. Mehta, J.A. Sears, S.L. Scott, and D.W. Hoyt. 2018. "Operando MAS NMR Reaction Studies at High Temperatures and Pressures." Journal of Physical Chemistry C 122, no. 15:8209-8215. PNNL-SA-130852. doi:10.1021/acs.jpcc.7b11442