Elucidation of molecular interactions between ionic liquid [Emim][triflate] with 2-methoxyethanol & N-methylpyrrolidone: Experimental and COSMO-RS studies

To progress the understanding of molecular interaction for the binaries of an IL, [Emim][triflate] with 2-methoxyethanol (ME) or N-methylpyrrolidone (NMP), thermo acoustic and volumetric properties such as speeds of sound (u) and densities (ρ) were measured as a function of temperature between (298.15–318.15) K over the entire composition range at ambient pressure. The combined volumetric and quantum-chemical (COSMO-RS) calculations have been utilized. These excess properties were fitted to Redlich-Kister type equation for acquiring the binary coefficients and standard deviations. Simultaneously, the COSMO-RS studies exhibited qualitative analysis of ion-pair formation, interactions of ion–dipole and hydrogen bonding between IL with the studied molecular solvents. The experimentally obtained excess molar volumes are further analyzed with the help of Prigogine–Flory–Patterson (PFP) theory.