(58g) in-Situ Spectroscopy of Lignin Disassembly

Lignin (an aromatic macromolecule in biomass) is considered as waste and under-utilized. A more appealing and value-added use of lignin is its disassembly into aromatic platform chemicals, which can be achieved by appropriate combinations of catalyst, solvent, and reaction conditions. Mechanistic reaction network studies of lignin disassembly are challenging, because the reactions require relatively high temperatures (above 200 °C) and pressures (above 80 bar), as well as the co-existence of solid, liquid, and gas phases. We have used in-situ magic-angle-spinning (MAS) solid-state nuclear magnetic resonance (NMR) and small angle neutron scattering (SANS) investigations to study catalytic disassembly of lignin at multiple length scales and in real-time. Our project leverages unique high-temperature and -pressure MAS NMR technology at the Pacific Northwest National Laboratory (PNNL) and a pressure reaction cell for collecting time-resolved neutron scattering data during thermochemical treatment of biomass at Oak Ridge National Laboratory.