Acid-free extraction of cellulose type I nanocrystals using Brønsted acid-type ionic liquids. Issue 2 (2nd April 2016) - Lazko, Jevgenij
Abstract: Extraction of cellulose type I nanocrystals from cotton fibers was straightforwardly carried out using exclusively Brønsted acid-type ionic liquids (ILs) via a two-step swelling/hydrolysis route, the switch between these two stages being induced by water addition. Since the whole process was achieved in a single reaction medium predominantly based on 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) and 1-(4-sulfobutyl)-3-methylimidazolium hydrogen sulfate ([SBMIM]HSO4 ), the process parameters were investigated in order to ensure a perfect compatibility and sequencing towards the two-step route proposed here. The impacts on nanoparticle morphology, crystallinity evolution, and cellulose type I to type II denaturation were observed under field-emission gun scanning electron microscopy and corroborated by X-ray diffraction characterizations. ILs recovery and reuse were also demonstrated, opening up new prospects of conception of multi-cycle, environmentally and economically sustainable processes. Abstract :