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Continuous catalytic depolymerisation and conversion of industrial kraft lignin into low-molecular-weight aromatics

Abdelaziz, Omar LU ; Li, Kena LU ; Tunå, Per LU and Hulteberg, Christian LU (2017) In Biomass Conversion and Biorefinery p.1-16
Abstract
Base-catalysed depolymerisation of lignin using sodium hydroxide has been shown to be an effective approach towards exploiting industrial (technical) lignins within the pulp and paper industry. In the present work, a pine kraft lignin (Indulin AT) which is precipitated from black liquor of linerboard-grade pulp was depolymerised via base catalysis to produce low-molecular-mass aromatics without any organic solvent/capping agent in a continuous-flow reactor setup for the first time. The catalytic conversion of lignin was performed/screened at temperatures varying from 170 to 250 °C, using NaOH/lignin weight ratio ≈ 1 with 5 wt% lignin solids loadings for residence times of 1, 2 and 4 min, respectively, with comprehensive characterisation of... (More)
Base-catalysed depolymerisation of lignin using sodium hydroxide has been shown to be an effective approach towards exploiting industrial (technical) lignins within the pulp and paper industry. In the present work, a pine kraft lignin (Indulin AT) which is precipitated from black liquor of linerboard-grade pulp was depolymerised via base catalysis to produce low-molecular-mass aromatics without any organic solvent/capping agent in a continuous-flow reactor setup for the first time. The catalytic conversion of lignin was performed/screened at temperatures varying from 170 to 250 °C, using NaOH/lignin weight ratio ≈ 1 with 5 wt% lignin solids loadings for residence times of 1, 2 and 4 min, respectively, with comprehensive characterisation of substrate and produced reaction mixtures. The products were characterised using size exclusion chromatography (SEC), nuclear magnetic resonance spectroscopy (NMR) and supercritical fluid chromatography-diode array detector-tandem mass spectrometry (SFC-MS). The optimum operating conditions for such depolymerisation appeared to be at 240 °C and 30 h−1, yielding the highest concentration of low-molecular-weight phenolics below the coking point. It was also found that the depolymerised lignin products exhibited better chemical stability during long-term storage at lower temperatures (~ 4 °C). (Less)
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Contribution to journal
publication status
published
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in
Biomass Conversion and Biorefinery
pages
16 pages
publisher
Springer
ISSN
2190-6823
DOI
10.1007/s13399-017-0294-2
language
English
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yes
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0a960e7c-77d6-4ec4-a635-b772750961ad
date added to LUP
2017-11-29 11:56:25
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2017-11-29 18:12:54
@article{0a960e7c-77d6-4ec4-a635-b772750961ad,
  abstract     = {Base-catalysed depolymerisation of lignin using sodium hydroxide has been shown to be an effective approach towards exploiting industrial (technical) lignins within the pulp and paper industry. In the present work, a pine kraft lignin (Indulin AT) which is precipitated from black liquor of linerboard-grade pulp was depolymerised via base catalysis to produce low-molecular-mass aromatics without any organic solvent/capping agent in a continuous-flow reactor setup for the first time. The catalytic conversion of lignin was performed/screened at temperatures varying from 170 to 250 °C, using NaOH/lignin weight ratio ≈ 1 with 5 wt% lignin solids loadings for residence times of 1, 2 and 4 min, respectively, with comprehensive characterisation of substrate and produced reaction mixtures. The products were characterised using size exclusion chromatography (SEC), nuclear magnetic resonance spectroscopy (NMR) and supercritical fluid chromatography-diode array detector-tandem mass spectrometry (SFC-MS). The optimum operating conditions for such depolymerisation appeared to be at 240 °C and 30 h−1, yielding the highest concentration of low-molecular-weight phenolics below the coking point. It was also found that the depolymerised lignin products exhibited better chemical stability during long-term storage at lower temperatures (~ 4 °C).},
  author       = {Abdelaziz, Omar and Li, Kena and Tunå, Per and Hulteberg, Christian},
  issn         = {2190-6823},
  language     = {eng},
  pages        = {1--16},
  publisher    = {Springer},
  series       = {Biomass Conversion and Biorefinery},
  title        = {Continuous catalytic depolymerisation and conversion of industrial kraft lignin into low-molecular-weight aromatics},
  url          = {http://dx.doi.org/10.1007/s13399-017-0294-2},
  year         = {2017},
}