Author(s)

Idi Guga Audu^1,2,3,4, Isabelle Ziegler-Devin², Heiko Winter^1,3, Martina Bremer⁴, Anton Hoffmann⁴, Steffen Fischer⁴, Marie-Pierre Laborie^1,3, Nicolas Brosse^2*

¹Chair of Forest Biomaterials, University of Freiburg, Freiburg, Germany.
²LERMaB, Faculty of Science and Technology, University of Lorraine, Nancy, France.
³Freiburg Materials Research Center (FMF), Freiburg, Germany.
⁴Institute of Plant and Wood Chemistry, Technische Universität Dresden, Dresden, Germany.

This study aims at investigating the impact of ionic liquid extraction on lignin structure by studying the mechanism of lignin depolymerization in 1-ethyl-3-methylimidazolium acetate EMIM[OAc]) and comparing it with that of organosolv and milled wood methods. Ionic liquid mediated lignin (ILL) using EMIM[OAc]), ethanol organosolv lignin (EOL) and milled wood lignin (MWL) were isolated from Typha capensis (TC) and subjected to several analytical characterizations. Experimental data shows that ILL exhibited a relatively lower degree of condensation, lower aromatic C-C structures and a higher aliphatic OH with values of 0.42/Ar, 1.94/Ar and 1.33/Ar moieties compared with EOL values of 0.92/Ar, 2.22/Ar and 0.51/Ar moieties respectively. The ILL was depolymerized under mild conditions giving relatively higher β-aryl ether linkages content, higher molecular mass, and exhibited closer structures and reactivity to native lignin than EOL. These insights on TC lignin depolymerization in EMIM[OAc]) acetate may contribute to better value-addition of lignocellulosic biomass.

1-Ethyl-3-Methylimidazolium Acetate, Ionic Liquid Lignin, Ethanol Organosolv Lignin, Lignin Depolymerization, Milled Wood Lignin

Audu, I. , Ziegler-Devin, I. , Winter, H. , Bremer, M. , Hoffmann, A. , Fischer, S. , Laborie, M. and Brosse, N. (2017) Impact of Ionic Liquid 1-Ethyl-3-Methylimidazolium Acetate Mediated Extraction on Lignin Features. Green and Sustainable Chemistry, 7, 114-140. doi: 10.4236/gsc.2017.72010.