(570f) Role of Catalyst Supports on Transfer Hydrogenolysis of Lignins in Glycerol-Derived Solvents

Lignin, comprising 15 to 30 wt% of lignocellulosic biomass, stands as the most abundant aromatics source. Thermocatalytic lignin deconstruction yields monomers which are chemicals or platform chemicals of high value as evidenced in their fine chemicals, pharmaceutical ingredients, and sustainable aviation fuels applications. Recent research has focused on enhancing the selective reductive catalytic fractionation (RCF) lignin deconstruction process by eliminating the need for high-pressure molecular hydrogen and volatile solvents. In a catalytic transfer hydrogenolysis (CTH) study, we successfully employed glycerol diethers derived from glycerol byproduct of biodiesel production, specifically 1-3-dimethoxypropan-2-ol (DMP) and 1,3-diethoxypropan-2-ol (DEP), as solvents for efficient depolymerization of lodgepole pine lignin. Monomer yields and delignification up to 25% and 91% were respectively achieved. With insights gained from spectroscopic and spectrometric analyses, as well as key reaction parameter variations, our current focus is on understanding the role of catalyst supports in driving the selectivity for individual monomers, as well as overall high yield of monomers. We are synthesizing and characterizing a range of metal-oxide and zeolite catalyst supports, alongside commercial Pt/C and Ru/C catalysts, to evaluate their activity and selectivity in the CTH process. Furthermore, our study aims to investigate how the surface Lewis or Brønsted acidity of the catalysts, and the hydrogen-adsorbing capability of metals influence the stabilization of reactive radical intermediates. This study advances low-pressure lignin deconstruction process, leading to the production of valuable products through favorable catalysis in the CTH process.