Reductive Partial Depolymerization of Acetone Organosolv Lignin to Tailor Lignin Molar Mass, Dispersity, and Reactivity for Polymer Applications

Lignin partial depolymerization by reduction (PDR) was developed as a strategy to tailor technical lignin’s molar mass and reduce its heterogeneity potentially increase the reactivity of lignin hydroxyl groups in polymer applications such PU foams coatings. The process aims cleave remaining β-O-4 linkages, thereby reducing large fragments overall dispersity. Acetone organosolv from pilot-scale fractionation industrial-size wood chips depolymerized using methanol, Ru/C catalyst, externally supplied hydrogen. effect reaction temperatures (in presence absence catalyst) fully detailed SEC, 31P NMR, 2D-HSQC NMR analyses lignin. catalyst promoted hydrogenolysis slightly increased aliphatic OH content. Process parameter screening showed effective at high concentrations but required relatively loadings. PDR efficiency proved be dependent on quality. A less-condensed with higher content improved ether cleavage, yielding lower after formation 4-n-propanol end groups. Overall, provides control over key characteristics, which turn offers potential biobased properties for various applications.