Using 2D NMR to characterize the structure of the low and high molecular weight fractions of bio-oil obtained from LignoBoost (TM) kraft lignin depolymerized in subcritical water
Journal article, 2016
In this work a multilevel analysis approach have been used for characterization of LignoBoostTM kraft lignin and bio-oil produced from LignoBoostTM kraft lignin using a process based on subcritical water (350 degrees C, 25 MPa). LignoBoostTM kraft lignin and the different fractions of the bio-oil (light oil, heavy oil and suspended solids) was characterized with high field NMR (18.8 T, 2D(13)C, H-1-HSQC NMR and C-13-NMR), GPC, GC-MS and elemental composition to improve understanding of the subcritical process. By using high resolution 2D HSQC NMR it was possible determine the chemical structures both on low and high molecular weight fractions of the bio-oil. It was confirmed that the signals from the aliphatic lignin inter-unit linkages, i.e. beta-O-4', beta-beta', beta-1' and beta-5', had disappeared from all of the bio-oil fractions studied. This means that both the aliphatic carbon-oxygen (C-O) and to some extent carbon-carbon (C-C) bonds in LignoBoostTM kraft lignin have been cleaved and an effective depolymerization has occurred. However, re-polymerization into higher molecular weight (Mw) fractions takes place simultaneously. These higher Mw fractions (heavy oil and suspended solids) were found to be re-polymerized macromolecules, with new structural networks based on guaiacol/disubstituted aromatic ethers and polyaromatic hydrocarbon structures bound tightly together. (C) 2016 Elsevier Ltd. All rights reserved.
chemical recovery
hydrothermal conversion
Biotechnology & Applied Microbiology
supercritical water
Char heteronuclear single
Subcritical water
base-catalyzed depolymerization
Bio-oil
Base-catalyzed depolymerization (BCD)
water
phenol mixtures
Phenol
organosolv lignin
near-critical water
substituted phenols
hot-compressed
p-cresol
Agriculture
Energy & Fuels
Author
Cecilia Mattsson
Chalmers, Chemistry and Chemical Engineering, Chemical Technology
Sven-Ingvar Andersson
Chalmers, Chemistry and Chemical Engineering, Chemical Technology
Tallal Belkheiri
Chalmers, Energy and Environment, Industrial Energy Systems and Technologies
Lars-Erik Åmand
Chalmers, Energy and Environment, Industrial Energy Systems and Technologies
L. Olausson
Valmet
Lennart Vamling
Chalmers, Chemistry and Chemical Engineering, Chemical Technology
Hans Theliander
Chalmers, Chemistry and Chemical Engineering, Chemical Technology
Wallenberg Wood Science Center (WWSC)
Biomass and Bioenergy
0961-9534 (ISSN) 18732909 (eISSN)
Vol. 95 364-377Subject Categories
Paper, Pulp and Fiber Technology
Polymer Technologies
DOI
10.1016/j.biombioe.2016.09.004