(251b) Counter-Current Chromatography for Separating Lignin Monomers from Reductive Catalytic Fractionation Oils from Various Feedstocks

Lignin-first biorefining aims to fractionate lignocellulosic biomass into a polysaccharide-rich pulp and a stabilized lignin oil. Among lignin-first biorefining methods, reductive catalytic fractionation (RCF) has received substantial attention as a process to selectively extract lignin from the plant cell wall, cleave aryl-ether linkages, and catalytically stabilize the resulting reactive aromatic intermediates using a hydrogen donor. RCF has been shown to be a feedstock-agnostic process, able to effectively extract and depolymerize lignin from hardwoods, softwoods, and grasses into oils rich in monomers and oligomers. Converting these products into valuable chemicals and materials is reliant on the development of advanced separation processes capable of monomer-monomer and monomer-oligomer separations with minimal energy/chemical inputs. To that end, here we demonstrate that counter-current chromatography (CCC) is a promising chromatographic technique for this application. In this presentation, we will discuss the separation and isolation of lignin-derived monomers using CCC from RCF oils of softwoods, hardwoods, and grasses, which exhibit key differences in lignin chemistry that dictate solvent choice. Based on the experimental data, a techno-economic analysis of the downstream process using CCC will be presented and compared with other separation approaches.