Ionic liquids, the mixture of ionic liquids and their co-solvent with N, N-dimethylformamide as solvents for cellulose using experimental and COSMO study

Abstract

Efficacy of mixtures of ionic liquids (ILs): 1-butyl-3-methylimidazolium acetate ([BMIM][OAc]) and 1-butyl-3-methylimidazolium thiocyanate ([BMIM][SCN]) with 4:1 mol/mol ratio was investigated to dissolve cellulose and compared with parent ILs. Attempt to reduce the mass transport limitations, viscosity was reduced by adding N, N-dimethylformamide (DMF) as a co-solvent in each system and found that ([BMIM][OAc] + DMF) mixture proved that the addition of a co-solvent enhances cellulose dissolution to 22.3 g per 100 g of solvent which is more than double in [BMIM][OAc] IL. The COSMO analysis study incorporated density functional theory (DFT) calculations which confirmed the experimental results obtained in this study. In addition to the above, a study was also conducted from a thermophysical perspective to confirm the qualitative dissolution. Distilled water was used to regenerate cellulose from the mixtures and characterized using thermogravimetric analysis (TGA), X-ray diffraction (p-XRD), scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR) to confirm the structure identification.

Keywords

• Cellulose dissolution
• Ionic liquids
• Kamlet-Taft model
• COSMO