Lignin and other aromatic substances released from spruce wood during pressurized hot-water extraction, Part 2: Structural characterization

Ivan Sumerskiy, Andrey Pranovich, Bjarne Holmbom, Stefan Willför

Research output: Contribution to journalArticleScientificpeer-review

3 Citations (Scopus)

Abstract

Extraction of ground spruce sapwood with pressurized hot water in an accelerated solvent extractor (ASE) at 170 degrees C during 20, 60, and 100 min resulted in isolation of galactoglucomannans and aromatic substances, including lignin. The isolated lignin preparations were characterized by spectrometric (UV, FT-IR, H-1 NMR, liquid and solid-state C-13 NMR), chromatographic (RP-HPLC, HP-SEC, GC-FID, and GC-MS), conventional pyrolysis, thermally assisted hydrolysis, and methylation techniques in tandem with GC-MS, and classical wet chemistry (methoxyl groups, total and phenolic hydroxyl groups, derivatization followed by reductive cleavage-DFRC). The content of beta-O-4 bonds in isolated lignins was similar to that in MWL and their proportion decreased with extraction time. The oxidation of isolated lignins and content of total hydroxyl groups were significantly increased with extraction time. The lignin structure underwent condensation and demethylation reactions during hot-water extraction. The induction of new phenylcoumaran substructures was proposed in isolated lignins.
Original languageUndefined/Unknown
Pages (from-to)398–411
Number of pages14
JournalJournal of Wood Chemistry and Technology
Volume35
Issue number6
DOIs
Publication statusPublished - 2015
MoE publication typeA1 Journal article-refereed

Keywords

  • Functional groups
  • hot-water extraction
  • lignin characterization
  • spruce wood
  • structural chemical analysis

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