Issue 14, 2017

Structural changes of poplar wood lignin after supercritical pretreatment using carbon dioxide and ethanol–water as co-solvents

Abstract

To delineate the structural changes of lignin during supercritical carbon dioxide pretreatment with ethanol–water as co-solvents (SCEP), enzymatic hydrolysis lignin (EHL) in original poplar chips, residual lignin in SCEP pretreated residues (SCEP-RL) and lignin dissolved in the SCEP liquors (SCEP-DL) were sequentially isolated and systematically characterized by GPC, quantitative 13C-NMR, 31P-NMR, 2D-HSQC NMR and TGA. After SCEP process, 19.2% of lignin was degraded and dissolved into SCEP liquors, while 4.8% of lignin was still present in the pretreated residues. It was also convinced that parts of the β-O-4 aryl ether linkages were cleaved and some of the stilbene, resinol (β–β) and phenylcoumaran (β-5) units were increased during SCEP process. Furthermore, the contents of free phenolic hydroxyl groups and carboxylic acids in SCEP-RL and SCEP-DL were higher than that of EHL.

Graphical abstract: Structural changes of poplar wood lignin after supercritical pretreatment using carbon dioxide and ethanol–water as co-solvents

Supplementary files

Article information

Article type
Paper
Submitted
01 nov 2016
Accepted
15 jan 2017
First published
24 jan 2017
This article is Open Access
Creative Commons BY license

RSC Adv., 2017,7, 8314-8322

Structural changes of poplar wood lignin after supercritical pretreatment using carbon dioxide and ethanol–water as co-solvents

X. Wang, Y. Guo, J. Zhou and G. Sun, RSC Adv., 2017, 7, 8314 DOI: 10.1039/C6RA26122A

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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