Structural characterization of birch lignin isolated from a pressurized hot water extraction and mild alkali pulped biorefinery process

A1 Journal article (refereed)


Internal Authors/Editors


Publication Details

List of Authors: L. Lagerquist, A. Pranovich, A. Smeds, S. von Schoultz, L. Vähäsalo, J. Rahkila, I. Kilpeläinen, T. Tamminen, S. Willför, P. Eklund
Publisher: Elsevier
Publication year: 2018
Journal: Industrial Crops and Products
Journal acronym: Ind. Crops Prod.
Volume number: 111
Start page: 306
End page: 316
Number of pages: 11
ISSN: 0926-6690
eISSN: 1872-633X


Abstract

In this work we have characterized a mild soda pulped birch (betula pendula) lignin after a novel pressurized hot water extraction pilot process. In the process hemicelluloses are first isolated from woods chips with hot water at oxygen-starved conditions, followed by mild alkali pulping at oxygen-starved conditions to remove lignin from the cellulose. Lignin was precipitated, washed and fractionated from the black liquor and characterized by quantitative C-13 NMR, C-13 DEPT experiments, P-31 NMR, 2D HSQC, FTIR, size exclusion chromatography (SEC), elemental analysis, pyrolysis-gas chromatography-mass spectrometry (py-GC-MS), methoxyl group quantification and residual carbohydrate analysis after methanolysis. The structure was compared to a MWL of birch obtained from the same wood chips and the differences were an increase in phenolic hydroxyl groups, carboxylic groups, polydispersity index, and reduction of aliphatic hydroxyl groups. The process resulted in beta-O-4 cleavage and condensation of the structure. This lignin is therefore suitable to be used in its polymeric form, rather than for degradation of the structure to small building blocks.


Keywords

Aryl glycerol, Birch lignin, Condensed structures, lignin characterization, Milled wood lignin

Last updated on 2019-05-12 at 04:03