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Catalytic hydrothermal liquefaction of alkali lignin at low temperature: Effect of acid and base catalysts on phenolic monomers production.
- Source :
- Biomass Conversion & Biorefinery; Feb2024, Vol. 14 Issue 3, p4071-4080, 10p
- Publication Year :
- 2024
-
Abstract
- Developing efficient process and technologies for the conversion of lignin into valuable functional chemicals is an important aspect of the biorefinery concept. In this study, the effect of low-cost base catalyst (NaOH, KOH, K<subscript>2</subscript>CO<subscript>3</subscript> and Na<subscript>2</subscript>CO<subscript>3</subscript>) and acid catalyst formic acid (FA) was examined for the effective depolymerization of lignin into monomers of phenolic compounds at low temperatures (140, 160 and 180 °C). Also, different reaction residence time (30, 60 and 120 min.), catalyst amounts have been varied to optimize the liquefaction reaction conditions. In the case of non-catalytic experiments, maximum bio-oil yield (14.2 wt.%) was obtained at 160 °C for 30 min. reaction time. With K<subscript>2</subscript>CO<subscript>3</subscript> catalysts, maximum bio-oil yield of 26.0 wt.% was observed, whereas in case of formic acid (FA) catalyst lignin depolymerization is very effective as it produced maximum bio-oil yield of 78.0 wt.%. Bio-oils were characterized using GC–MS, FT-IR, NMR analytical methods. Bio-oil analysis showed that it contained higher amount of phenolic monomers after lignin depolymerization. Higher amount of vanillin (41.9%) and isovanillin (44.9%) was found without catalyst and with FA liquefaction reaction. However with base catalyst, dibutyl phthalate (28.8%) was observed as the major compound in lignin depolymerization derived bio-oil. Solid residue analysis shows that base and acid catalyst depolymerized lignin in different ways by breaking of C-O and C–C bonds. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 21906815
- Volume :
- 14
- Issue :
- 3
- Database :
- Complementary Index
- Journal :
- Biomass Conversion & Biorefinery
- Publication Type :
- Academic Journal
- Accession number :
- 175966709
- Full Text :
- https://doi.org/10.1007/s13399-022-02603-0