Dr. Cabezas-Cornejo, René

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.

In this study, the theoretical design of ionic liquids (ILs) for predicting selective extraction of lithium from brines has been conducted using COSMO-RS. A theoretical model for the solvent extraction (SX) of the metal species present in brines was established considering extraction stoichiometry, the distribution of the extractants between aqueous and IL phases, and IL dissociation in the aqueous phase. Theoretical results were validated using experimental extraction percentages from previous works. Results indicate that, in general, the theoretical results for lithium extraction follow experimental trends, except from magnesium extraction. Finally, based on the model, an IL was proposed that was based on the phosphonium cation as the extractant, along with the phase modifier tributylphosphate (TBP) in an organic diluent in order to improve selectivity for lithium ex- traction over sodium. These results provide an insight for the application of ILs in lithium processing, avoiding the long purification times reported in the conventional process.