title: Reductive de-polymerization of kraft lignin for chemicals and fuels using formic acid as an in-situ hydrogen source.
abstract: In this study, formic acid (FA) was employed as an in-situ hydrogen donor for the reductive de-polymerization of kraft lignin (KL). Under the optimum operating conditions, i.e., 300 °C, 1 h, 18.6 wt.% substrate concentration, 50/50 (v/v) water-ethanol medium with FA 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 1270 g/mol) at a yield of ∼90 wt.% and <1 wt.% yield of solid residue (SR). The MW of the DL products decreased with increasing reaction temperature, time and FA-to-lignin mass ratio. The sulfur contents of all DL products were remarkably lower than that in the original KL. It was also demonstrated that FA is a more reactive hydrogen source than external hydrogen for reductive de-polymerization of KL.
authors.affiliation: Department of Chemical and Biochemical Engineering, Faculty of Engineering, Western University, London, Ontario N6A 5B9, Canada.
authors.forename: Shanhua
authors.initials: S
authors.lastname: Huang
authors.affiliation: Department of Chemical and Biochemical Engineering, Faculty of Engineering, Western University, London, Ontario N6A 5B9, Canada.
authors.forename: Nubla
authors.initials: N
authors.lastname: Mahmood
authors.affiliation: Department of Chemical and Biochemical Engineering, Faculty of Engineering, Western University, London, Ontario N6A 5B9, Canada.
authors.forename: Matthew
authors.initials: M
authors.lastname: Tymchyshyn
authors.affiliation: Department of Chemical and Biochemical Engineering, Faculty of Engineering, Western University, London, Ontario N6A 5B9, Canada.
authors.forename: Zhongshun
authors.initials: Z
authors.lastname: Yuan
authors.affiliation: Department of Chemical and Biochemical Engineering, Faculty of Engineering, Western University, London, Ontario N6A 5B9, Canada. Electronic address: cxu6@uwo.ca.
authors.forename: Chunbao Charles
authors.initials: CC
authors.lastname: Xu
mesh_terms: D056804:Biofuels; D005561:Formates / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry; D008031:Lignin / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D010084:Oxidation-Reduction; D058105:Polymerization; D013696:Temperature
chemical_list: D056804:Biofuels; D005561:Formates; C030544:formic acid; D006859:Hydrogen; C076151:Kraft lignin; D008031:Lignin
keywords: De-polymerization; Formic acid; Hydrogen; Lignin; Molecular weight