Screening of solvents for carbon dioxide absorption in ionic liquids using cosmotherm

Abstract

Recently room temperature ionic liquids (ILs); called green solvents are emerging as promising candidates to capture due to their wide liquid range, low melting point, negligible vapor pressure, high solubility and reasonable thermal stability. However, these solvents, suffer from a major disadvantage of high viscosities in their unreacted state, which makes them very difficult to handle and transport in an industrial scenario. To make up for this, combining RTILs with conventional solvents like alkanolamines have been proposed.Again, owing to the huge number of possible combinations between cations and anions and blends of the resulted ILS/RTILs with alkanolamines, a solvent screening procedure became essential in narrowing down the solvents/blended solvents with the desired properties. In view of this, various thermophysical and physicochemical properties intended for CO2 absorption were predicted for the ionic liquids as well as their alkanolamine blends using the computational chemistry software “cosmotherm”.Various properties like density, heat capacities, viscosities, conductivity, melting point etc were studied by changing the substituent cation or anion of ILS/RTILs and their combinations with alkanolamines as well.On comparison of the predicted properties, it has been noticed that the anions TF2N and PF6 exhibits the most desirable properties in combination with the solvents MEA, DEA and PE.The screened solvents in this study might be proving their worth on experimental verification.