(329a) Feedstock-Agnostic Reductive Catalytic Fractionation in Alcohol and Alcohol-Water Mixtures

Feedstock flexibility is a key challenge for implementation of biomass conversion technologies at industrial scale due to the limited access to a single biomass feedstock with year-round availability at low cost. Reductive catalytic fractionation (RCF) is a promising lignin-first biorefining process, wherein lignin is selectively extracted from native plant cell wall with a polar protic solvent and depolymerized to stable aromatic monomers through reductive catalysis. In reports to date, RCF has been demonstrated to be applicable to a wide range of lignocellulosic feedstocks including hardwoods, softwoods, grasses, and agricultural residues, suggesting the potential for this process technology to be feedstock agnostic. To that end, here we study the impact of feedstock type on RCF performance to provide a self-consistent, comprehensive assessment regarding the feasibility of feedstock-agnostic RCF. Specifically, RCF was performed with poplar (hardwood), switchgrass (herbaceous monocot), corn stover (herbaceous monocot), and pine (softwood) at varying solvent compositions (alcohol and alcohol/water) in both batch and flow-through (FT) reactors.

Batch and FT reactions performed with methanol revealed delignification values and monomer yields greater than 65 wt% and 25 wt%, respectively, for the tested hardwood and grasses despite their inherent differences. RCF of pine exhibited lower lignin extraction efficiency (<40 wt%), but the high content of lignin in pine enabled a similar lignin oil yield on a biomass basis relative to other feedstocks. In the presence of water as a co-solvent, delignification values increased to greater than 78 wt% regardless of the tested feedstock. The comparable delignification values, together with similar lignin oil and carbohydrate yields observed across the tested feedstocks, suggest the potential of RCF with an alcohol/water mixture as a feedstock-agnostic process.