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

A1 Journal article (refereed)


Internal Authors/Editors


Publication Details

List of Authors: Ivan Sumerskiy, Andrey Pranovich, Bjarne Holmbom, Stefan Willför
Publisher: TAYLOR & FRANCIS INC
Publication year: 2015
Journal: Journal of Wood Chemistry and Technology
Journal acronym: J WOOD CHEM TECHNOL
Volume number: 35
Issue number: 6
Start page: 398
End page: 411
Number of pages: 14
ISSN: 0277-3813
eISSN: 1532-2319


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.


Keywords

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

Last updated on 2019-18-09 at 07:09