Lignin-first is an umbrella of methodologies with the common denominator of active stabilisation approaches that solubilise lignin from native lignocellulosic biomass while avoiding condensation reactions that lead to more recalcitrant lignin polymers. One such direction is reductive catalytic fractionation, where the reactive lignin-derived compounds are stabilized by reduction. Our group has developed a methodology that take advantage of the hemicellulose fraction as the reducing agent. By this, the energy content from the hemicellulose is conserved and transferred to the lignin by transfer hydrogenolysis reactions. Most lignin-first transformations are performed in batch where the wood is cooked in a liquor together with a transition metal catalyst. Disadvantages with this approach is both that pulping and hydrogen transfer reactions must have the same reaction conditions; the resulting pulp and the transition metal catalyst will be mixed and are difficult to separate after the reaction. We have developed a few technologies that separate the pulping and hydrogen transfer reactions in space and time, for example continuous flow. The products from such transformation is a pulp and a lignin derived oil consisting of up to 40% monophenolics. The exact yield of monophenolics is directly correlated to the number of beta-O-4 bonds in lignin, and thus 40% is a “theoretical maximum yield”. The rest of the lignin fraction consists of oligomers that up to date has received little attention. In this talk, we will discuss a novel approach to enhance the yield of monomers above the theoretical maximum.

Efficient raw material use by lignin-first approach

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.