Molecular dynamics simulations and COSMO-RS method for CO2 capture in imidazolium and pyrrolidinium-based room-temperature ionic liquids

The solubility of CO2 in different ionic liquids (ILs) was determined using molecular dynamics (MD) simulations and quantum calculations. MD simulation was used to study the interaction between IL and CO2 molecules at the interface. The solubility of CO2 is found to be higher in ILs containing [TF2N]– anion. The COSMO-RS model was used to determine the Henry’s law constants for CO2 in different ILs. With increasing molar volume of ILs, the Henry’s law constant of CO2 drops, which is in good accord with the solubility data obtained from MD simulations. The Henry’s law constants follow the sequence of [BMIM][PF6] > [PMIM][TF2N] > [BMIM][TF2N] > [BMPY][TF2N] > [HMIM][TF2N] > [OMIM][TF2N]. The MD simulations and quantum calculations have shown that [TF2N]– has a higher impact on CO2 solubility than [PF6]–; this information is useful for screening and designing of ILs for CO2 absorption.