Electronic Thesis and Dissertation Repository

Degree

Master of Engineering Science

Program

Chemical and Biochemical Engineering

Supervisor

Chunbao (Charles) Xu

Abstract

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.


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