Reductive catalytic fractionation of pine wood: elucidating and quantifying the molecular structures in the lignin oil
Korneel Van Aelst, Elien Van Sinay, Thijs Vangeel, E. Cooreman, Gil Van den Bossche, Tom Renders, Joost Van Aelst, Sander Van den Bosch, Bert F. Sels
Abstract
C HSQC NMR spectrum of the RCF oligomers. Specifically, β-5 γ-OH, β-5 ethyl, β-1 γ-OH, β-1 ethyl, β-β 2x γ-OH, β-β THF, and 5-5 inter-unit linkages were assigned unambiguously, resulting in the quantification of over 80% of the lignin inter-unit linkages and end-units. Detailed inspection of the native lignin inter-unit linkages and their conversion reveals the occurring hydrogenolysis chemistry and the unambiguous proof of absence of lignin fragment condensation during proper RCF processing. Overall, the study offers an advanced analytical toolbox for future RCF lignin conversion and lignin structural analysis research, and valuable insights for lignin oil valorization purposes.