Journal article
Solvent assisted catalytic conversion of beech wood and organosolv lignin over NiMo/γ-Al2O3
Department of Chemical and Biochemical Engineering, Technical University of Denmark1
Technical University of Denmark2
CHEC Research Centre, Department of Chemical and Biochemical Engineering, Technical University of Denmark3
Haldor Topsoe AS4
Department of Chemistry, Technical University of Denmark5
Center for Hyperpolarization in Magnetic Resonance, Centers, Technical University of Denmark6
Beech wood was directly converted into lignin derived monomers and dimers and holocellulose derived light hydrocarbons in the presence of a sulfided NiMo/γ-Al2O3 catalyst in ethanol medium at 200 to 300 °C. The reaction products were carefully analyzed with techniques such as gas chromatography mass spectrometry equipped with a flame ionization detector (GC-MS-FID), size exclusion chromatography (SEC), elemental analysis and heteronuclear single quantum coherence nuclear magnetic resonance (HSQC NMR).
The main identified monomers obtained at 300 °C were 4-propyl guaiacol (PG) and 4-propyl syringol (PS) with a total monomer yield of 18.1 wt% based on the Klason lignin content in beech wood. At a lower reaction temperature of 200 °C, the process targets only the lignin with a monomer yield of 12.1 wt% based on the Klason lignin content, while the holocellulose is conserved and can be used for a subsequent fermentation or hydrocracking process.
The highest monomer yield of 20.0 wt% based on the Klason lignin content was obtained at 260 °C, indicating that the optimum temperature required for degradation of lignin fractions to monomers is within 200-260 °C. The direct conversion of biomass with high yield of lignin monomers showed promise compared to a two-step process involving initial isolation of lignin by the organosolv method and subsequent conversion of organosolv lignin.
Here, a monomer yield of only 4.3 wt% was detected at 300 °C. Moreover, the oil from the direct biomass conversion possessed a lower molecular weight compared to the oil from the organosolv lignin conversion.
Language: | English |
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Year: | 2020 |
Pages: | 1844-1854 |
ISSN: | 23984902 |
Types: | Journal article |
DOI: | 10.1039/c9se00375d |
ORCIDs: | Christensen, Jakob Munkholt , Duus, Jens Øllgaard and Jensen, Anker Degn |