Structural Analysis of Lignins from Different Sources

Authors: I. F. Fiţigău, F. Peter, C. G. Boeriu

Abstract:

Five lignin samples were fractionated with Acetone/Water mixtures and the obtained fractions were subjected to extensive structural characterization, including Fourier Transform Infrared (FT-IR), Gel permeation Chromatography (GPC) and Phosphorus-31 NMR spectroscopy (31P-NMR). The results showed that for all studied lignins the solubility increases with the increment of the acetone concentration. Wheat straw lignin has the highest solubility in 90/10 (v/v) Acetone/Water mixture, 400 mg lignin being dissolved in 1 mL mixture. The weight average molecular weight of the obtained fractions increased with the increment of acetone concentration and thus with solubility. 31P-NMR analysis based on lignin modification by reactive phospholane into phosphitylated compounds was used to differentiate and quantify the different types of OH groups (aromatic, aliphatic, and carboxylic) found in the fractions obtained with 70/30 (v/v) Acetone/Water mixture.

Keywords: Lignin, fractionation, FT-IR, GPC, 31P-NMR.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1331679

References:

[1] K. V. Sarkanen, C. H. Ludwig, Lignins: Occurrence, Formation, Structure and Reactions, Wiley-Interscience, New-York, 1971.
[2] A.T Martinez, M. Speranza, F.J. Ruiz-Duenas, P. Ferreira, S. Camarero, F. Guillen, M.J. Martinez, A. Gutierrez, J.C. del Rio, "Biodegradation of lignocellulosics: microbial, chemical, and enzymatic aspects of the fungal attack of lignin", Int Microbiol, vol. 8, pp. 195-204, 2005.
[3] M. Dashtban, H. Schraft, T. A. Syed, W. Qin, "Fungal biodegradation and enzymatic modificationof lignin", Int J Biochem Mol Biol, vol. 1(1) pp. 36-50, 2010.
[4] E. A. Capanema, M. YU. Balakshin, J. F. Kadla, "Quantitative Characterization of a Hardwood Milled Wood Lignin by Nuclear Magnetic Resonance Spectroscopy", J. Agric. Food Chem. vol. 53, pp. 9639- 9649, 2005.
[5] J.R. Obst, " Guaiacyl and Syringyl Lignin Composition in Hardwood Cell Components", Holzforschung, vol. 36, pp. 143-152, 1982
[6] J.R. Rostrup-Nielsen, "Chemistry: making fuels from biomass", Science vol. 308, pp. 1421-1422, 2005.
[7] D. Yang, X. Qiu, M. Zhou, H. Lou, "Properties of sodium lignosulfonate as dispersant of coal water slurry", Energy Convers. Manage., vol. 48 pp. 2433-2438, 2007.
[8] C. Pouteau, P. Dole, B. Cathala, L. Averous, N. Boquillon, "Antioxidant properties of lignin in polypropylene", Polymer Degradation and Stability, vol. 81, pp. 9-18, 2003.
[9] A. Granata, D. S. Argyropoulos, "2-Chloro-4,4,5,5-tetramethyl-1,3,2- dioxaphospholane, a reagent for the accurate determination of the uncondensed and condensed phenolic moieties in lignins", J. Agric. Food Chem., vol. 43, pp. 1538-1544, 1995.
[10] Y. Ni, Q. Hu, "Alcell lignin solubility in ethanol-water mixtures" J. Appl. Polym. Sci., vol. 57, pp. 1441-1446, 1995.
[11] O., Faix, Fourier transformed infrared spectroscopy, In: S.Y., Lin, C.W. Dence, (Eds.), Methods in Lignin Chemistry, Springer-Verlag, Berlin- Heidelberg, pp. 458-464, 1992.
[12] C. G. Boeriu, D. Bravo, R.J.A. Gosselink, J.E.G. van Dam "Characterisation of structure-dependent functional properties of lignin with infrared spectroscopy", Industrial Crops and Products, vol. 20, pp. 205-218, 2004.
[13] Y. Pu ,S. Cao, A. J. Ragauskas, "Application of quantitative 31P-NMR in biomass lignin and biofuel precursors characterization", Energy Environ. Sci., vol. 4, pp. 3154 - 3166, 2011.
[14] F. Abdelkafi, H. Ammar, B. Rousseau, M. Tessier, R. El Gharbi, A. Fradet, "Structural analysis of alfa grass (Stipa tenacissima L.) lignin obtained by acetic acid/formic acid delignification", Biomacromolecules, vol. 12, pp. 3895−3902, 2011.