Dissolution of less-processed wood fibers without bleaching in an ionic liquid: Effect of lignin condensation on wood component dissolution.

This study evaluated the solubility of low-processed wood fibers produced from a low temperature acid hydrotropic fractionation (AHF) in an ionic liquid (IL) 1,5-diazabicyclo[4.3.0]non-5-enium acetate (DBNH[OAc]. Unbleached wood fibers produced from AHF lignin fractionation using p-Toluenesulfonic acid (p-TsOH) with or without post-treatments with lignin and hemicelluloses content up to 15% and 25%, respectively, were dissolved directly into the IL DBNH[OAc]. Post-AHF fractionation treatments using dilute alkaline and glycerol swelled the cellulose and partially removed residual lignin resulting in improved dissolution. Semi-quantitative 2D HSQC NMR analyses revealed that the undissolved wood fiber residues were enriched with G units and condensed S units (Scond), demonstrating, as expected, that G units and condensed lignin substructures have a negative effect on dissolution in DBNH[OAc]. Therefore, AHF with rapid fractionation at low temperatures offers a promising advantage over existing high temperature pulp dissolving fiber (PDF) processes in terms of reducing energy input, lowering lignin content as well as reducing lignin condensation for producing MMCF.
PMID: 31100399 [PubMed - as supplied by publisher]

Source: International Journal of Biological Macromolecules - May 13, 2019 Category: Biochemistry Authors: Wang H, Hirth K, Zhu J, Ma Q, Liu C, Zhu JY Tags: Int J Biol Macromol Source Type: research