Electronic Thesis and Dissertation Repository


Master of Engineering Science


Chemical and Biochemical Engineering


Chunbao (Charles) Xu


In this thesis work, formic acid (FA) proved to be an effective in-situ hydrogen donor for the reductive de-polymerization of kraft lignin (KL). At the optimum conditions without catalysts, i.e., 300 oC, 1 h, 18.6 wt.% substrate concentration, 50/50 (v/v) water-ethanol medium at a FA-to-lignin mass ratio of 0.7, KL (Mw ~10,000 g/mol) was effectively de-polymerized, producing de-polymerized lignin (DL, Mw 1, 270 g/mol) at a yield of ~90 wt.% and wt.% yield of solid residue (SR). The effects of heterogeneous catalysts on KL reductive de-polymerization in 50/50 (v/v) water-ethanol medium were also investigated. At all conditions, FHUDS-2 (W-Mo-Ni) catalyst showed very high efficiency in sulfur-removal, and Ru10%/C exhibited excellent activity for de-polymerization and hydrogenation of the de-polymerized lignin products. However at a lower temperature (200 °C), Ni10%/Zeolite catalyst demonstrated superb catalytic activity for reductive de-polymerization of KL, producing 93.5(±4.1) wt.% yield of DL of Mw = 3150 g/mol.