Efficient Mild Organosolv Lignin Extraction in a Flow-Through Setup Yielding Lignin with High beta-O-4 Content

Douwe S. Zijlstra, Coen A. Analbers, Joren de Korte, Erwin Wilbers, Peter J. Deuss*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

17 Citations (Scopus)
119 Downloads (Pure)

Abstract

Current lignin fractionation methods use harsh conditions that alter the native lignin structure, resulting in a recalcitrant material which is undesired for downstream processing. Milder fractionation processes allow for the isolation of lignins that are high in beta-aryl ether (beta-O-4) content, however, at reduced extraction efficiency. The development of improved lignin extraction methods using mild conditions is therefore desired. For this reason, a flow-through setup for mild ethanosolv extraction (120 degrees C) was developed. The influence of acid concentration, ethanol/water ratio, and the use of other linear alcohol co-solvents on the delignification efficiency and the beta-O-4 content were evaluated. With walnut shells as model feedstock, extraction efficiencies of over 55% were achieved, yielding lignin with a good structural quality in terms of beta-O-4 linking motifs (typically over 60 per 100 aromatic units). For example, lignin containing 66 beta-O-4 linking motifs was obtained with an 80:20 n-propanol/water ratio, 0.18 M H2SO4 with overall a good extraction efficiency of 57% after 5 h. The majority of the lignin was extracted in the first 2 hours and this lignin showed the best structural quality. Compared to batch extractions, both higher lignin extraction efficiency and higher beta-O-4 content were obtained using the flow setup.

Original languageEnglish
Article number1913
Number of pages17
JournalPolymers
Volume11
Issue number12
DOIs
Publication statusPublished - Dec-2019

Keywords

  • biomass
  • lignin
  • flow-through setup
  • organosolv extraction
  • high beta-O-4 content
  • REDUCTIVE CATALYTIC FRACTIONATION
  • PRIMARY ALCOHOL OXIDATION
  • FLOWTHROUGH PRETREATMENT
  • BIOMASS
  • ACID
  • DEPOLYMERIZATION
  • LIGNOCELLULOSE
  • OPTIMIZATION
  • VALORIZATION
  • SOLVOLYSIS

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