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

Energy & Fuels

Agriculture

Bio-oil

Base-catalyzed depolymerization (BCD)

water

phenol mixtures

Phenol

p-cresol

hot-compressed

substituted phenols

organosolv lignin

near-critical water

Author

Cecilia Mattsson

Chalmers, Chemistry and Chemical Engineering, Chemical Technology, Forest Products and Chemical Engineering

Sven-Ingvar Andersson

Chalmers, Chemistry and Chemical Engineering, Chemical Technology, Forest Products and Chemical Engineering

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, Forest Products and Chemical Engineering

Hans Theliander

Chalmers, Chemistry and Chemical Engineering, Chemical Technology, Forest Products and Chemical Engineering

Wallenberg Wood Science Center (WWSC)

Biomass and Bioenergy

0961-9534 (ISSN)

Vol. 95 364-377

Subject Categories

Paper, Pulp and Fiber Technology

Polymer Technologies

DOI

10.1016/j.biombioe.2016.09.004

More information

Latest update

9/15/2020