Lignin structure and aggregation behavior in a two-component ionic liquid solvent system.

Ionic liquids are of potential interest in the processing of lignocellulosic biomass. In this study, the ionic liquid co-solvent system of 1-methylimidazole (MIM) and 1-ethyl-3-methyl-imidazolium acetate (EMIMAc) was used to solvate LignoBoost lignin fractionated from black liquor obtained from a kraft paper mill. Lignin ethanol-precipitated (LEP) and ethanol-soluble (LES) fractions were characterized via gel permeation chromatography (GPC) and 13C- and 31P-nuclear magnetic resonance spectroscopy (NMR) to determine structural characteristics and their relationship to polymer solubility in the system. Polymer integrity and solubility were optimal at ~20% lignin loading (w/w). Results showed that LEPs were generally of higher apparent molecular weight (Mw) and enriched with condensed/aliphatic ether linkages and aliphatic hydroxyls. The LESs had a lower apparent Mw and were enriched with carboxylic and phenolic groups. This newly gained knowledge on lignin fractionation and aggregation in the present solvent system provides future opportunities for tuning fractionation/extraction to suit a specific biomass-derived product, e.g., carbon fibers

[1]  G. Westman,et al.  Solvation Behavior of Cellulose and Xylan in the MIM/EMIMAc Ionic Liquid Solvent System: Parameters for Small-Scale Solvation , 2013 .

[2]  A. Ragauskas,et al.  Polymerization of Kraft lignin via ultrasonication for high-molecular-weight applications. , 2013, Ultrasonics sonochemistry.

[3]  G. Gellerstedt,et al.  A new method for stabilizing softwood kraft lignin fibers for carbon fiber production , 2013 .

[4]  H. Sixta,et al.  Separation of hemicellulose and cellulose from wood pulp by means of ionic liquid/cosolvent systems. , 2013, Biomacromolecules.

[5]  Thomas Q. Hu,et al.  Chemical Modification, Properties, and Usage of Lignin , 2013, Springer US.

[6]  U. Jadhav,et al.  Lignin: Properties and applications in biotechnology and bioenergy , 2012 .

[7]  C. Crestini,et al.  Milled wood lignin: a linear oligomer. , 2011, Biomacromolecules.

[8]  Luca Zoia,et al.  Molecular weight distributions and linkages in lignocellulosic materials derivatized from ionic liquid media. , 2011, Journal of agricultural and food chemistry.

[9]  Kenneth N. Marsh,et al.  Extracting wood lignin without dissolving or degrading cellulose: investigations on the use of food additive-derived ionic liquids , 2011 .

[10]  Jyri-Pekka Mikkola,et al.  Dissolution of lignocellulosic materials and its constituents using ionic liquids - a review , 2010 .

[11]  D. Argyropoulos.  Heteronuclear NMR Spectroscopy of Lignins , 2010 .

[12]  Antonio F. Patti,et al.  Extraction of lignin from lignocellulose at atmospheric pressure using alkylbenzenesulfonate ionic liquid , 2009 .

[13]  Huajiang Huang,et al.  A review of separation technologies in current and future biorefineries , 2008 .

[14]  Xiaolian Gao,et al.  Z‐restored spin‐echo 13C 1D spectrum of straight baseline free of hump, dip and roll , 2008, Magnetic resonance in chemistry : MRC.

[15]  S. Grimme.  Do special noncovalent pi-pi stacking interactions really exist? , 2008, Angewandte Chemie.

[16]  D. Stewart.  Lignin as a base material for materials applications: Chemistry, application and economics , 2008 .

[17]  Alistair King,et al.  Dissolution of wood in ionic liquids. , 2007, Journal of agricultural and food chemistry.

[18]  C. Crestini,et al.  On the propensity of lignin to associate: a size exclusion chromatography study with lignin derivatives isolated from different plant species. , 2007, Phytochemistry.

[19]  G. Henriksson,et al.  Characterisation of lignin-carbohydrate complexes (LCCs) of spruce wood (Picea abies L.) isolated with two methods. , 2006 .

[20]  B. Cathala,et al.  Association behaviour of lignins and lignin model compounds studied by multidetector size-exclusion chromatography. , 2003, Journal of chromatography. A.

[21]  D. Argyropoulos,et al.  Abundance and reactivity of dibenzodioxocins in softwood lignin. , 2002, Journal of agricultural and food chemistry.

[22]  B. Cathala,et al.  Influence of pectins on the solubility and the molar mass distribution of dehydrogenative polymers (DHPs, lignin model compounds). , 2001, International journal of biological macromolecules.

[23]  A. Ragauskas,et al.  Nuclear magnetic resonance studies. 4. Analysis of residual lignin after Kraft pulping , 1998 .

[24]  C. Crestini,et al.  Structural Analysis of Wheat Straw Lignin by Quantitative 31P and 2D NMR Spectroscopy. The Occurrence of Ester Bonds and α-O-4 Substructures , 1997 .

[25]  Y. Ni,et al.  Alcell® lignin solubility in ethanol–water mixtures , 1995 .

[26]  D. Teller,et al.  Lignin. 20. Associative interactions between kraft lignin components , 1984 .

[27]  A. Björkman,et al.  Studies on finely divided wood. Part 1. Extraction of lignin with neutral solvents , 1956 .

[28]  J. Ralph,et al.  NMR of lignins , 2010 .

[29]  H. Theliander,et al.  A novel method for washing lignin precipitated from kraft black liquor – Laboratory trials , 2007 .

[30]  J. Mccarthy,et al.  Gel Chromatography and Association Complexes of Lignin , 1980 .

[31]  Kyosti V. Sarkanen,et al.  Lignins : occurrence, formation, structure and reactions , 1971 .

[32]  Karl Freudenberg,et al.  Constitution and Biosynthesis of Lignin , 1968 .