Assessment of bio-ionic liquids as promising solvents in industrial separation processes: Computational screening using COSMO-RS method

Abstract

The use of organic solvents in the chemical industry for gas-liquid absorption or liquid-liquid extraction operations is still unavoidable. The search of “greener” solvents to replace fossil-based counterparts is a challenge for the scientific community. Biocompatible ionic liquids (bio-ILs) emerged as a sustainable approach for the development of greener processes. In this work, bio-ILs based on choline as common cation are evaluated as promising solvents in typical industrial separation processes such as gas absorption (refrigerants, CO2, H2S, NH3, or acetone) and liquid-liquid extraction (hydrocarbon separations, denitrogenation, desulfurization, and recovery of value-added compounds and/or contaminants from aqueous streams) by means of COSMO-RS method. Some bio-ILs show competitive behavior compared to the benchmark common ILs solvents for all the solutes evaluated. None of the solvents evaluated is predicted to form two liquid phases in aqueous solutions, so future work should be conducted on finding hydrophobic bio-ILs to perform these separations. On the other hand, bio-ILs in hydrocarbon separations by means of liquid-liquid extraction show competitive results in terms of selectivities (benzoate-based) and partition coefficients (bicarbonate-based) compared to benchmark sulfolane and common ILs previously tested