Cellulose dissolves in ionic liquids, ILs, allowing several applications (regeneration and transformation into derivatives). However, the cellulose solutions in some ILs are quite viscous or form gels, making difficult such applications. To avoid this issue, IL-molecular solvent (MS) or IL-water mixtures were being employed and this is the objective of this project. The aim is to choose an efficient IL-MS pair to dissolve cellulose. The solvation of binary mixtures is complicated due to the occurrence of preferential solvation, ie the accumulation of one of the component mixture in the solvation layer of solute. This phenomenon depends on the solute structures, the pair of solvents and the mutual interactions between them. Information about such interactions are obtained by using solvatochromic probes (compounds whose spectra are sensitive to the composition of the medium and the interactions probe-solvent). The ILs of interest have long side chain (1-heptyl-3-methylimidazolium acetate) C7MeImAc, and ether bonds (1-(3,6-dioxa)-1-heptyl-3-methylimidazolium acetate) C5O2MeImAc. The MSs will be dimethylsulfoxide and N, N-dimethylacetamide. IL-water mixtures will also be studied. The probes will be the ones already employed by this group in previous solvatochromic studies. The dissolution of microcrystalline and fibrous cellulose will be studied in the same binary mixtures and the dependence of the dissolution on the composition of the medium will be explained from solvatochromic data. The formation of nano-cellulose beads from these solutions will also be tested.
News published in Agência FAPESP Newsletter about the scholarship: