[Tf2n]-Based Ionic Liquids for the Selective Liquid-Liquid Extraction of Levulinic Acid/Formic Acid: Cosmo-Rs Screening and Ternary Lle Experimental Data

The separation of Levulinic (LA) acid and Formic acid (FA) from aqueous streams represents an important and challenging separation in biorefineries, where ionic liquids (ILs) provide a sustainable environment for liquid-liquid extractions of these acids. In this work, a COSMO-RS screening of bis (trifluoromethylsulfonil)imide [Tf2N] (-) based IL was first conducted and then followed by experimental validation to search for the most suitable cation for this separation. After the screening, ternary liquid-liquid equilibrium experiments at 298.15K and the subsequent data correlation using the Non-Random Two Liquid model (NRTL) were performed for future industrial implementation. Results indicated that the phosphonium cations, especially the trihexylthetradecyl phosphonium cation [P66614](+), produced the highest selectivity rates among all the experimentally measured ILs.