Topological analysis of thermodynamic properties of binary mixtures containing 1-butyl-3-methylimidazolium tetrafluoroborate and cycloalkanones

Abstract

This work presents densities, ρ, speeds of sound, u, and molar heat capacities, Cp, of 1-butyl-3-methylimidazolium tetrafluoroborate (1) + cyclopentanone or cyclohexanone (2) mixtures as a function of composition at 293.15, 298.15, 303.15, 308.15 K and excess molar enthalpies, HE of same mixtures at 298.15 K. The measured ρ, u and Cp values were used to calculate excess molar volumes, VE, excess isentropic compressibilities, \(\kappa_{\text{S}}^{\text{E}}\) and excess heat capacities, \(C_{\text{P}}^{\text{E}}\). The VE, \(\kappa_{\text{S}}^{\text{E}}\), HE and \(C_{\text{P}}^{\text{E}}\) have been tested in terms of Graph theory. The analysis of VE data and IR spectroscopic data has suggested that (1 + 2) mixtures are characterized by interactions between hydrogen and oxygen atom of cyclopentanone or cyclohexanone with fluorine atom of [BF4]− anion and proton of –CH3 group attached to imidazolium ring of [Bmim]+ cation. The quantum mechanical calculations also support the proposed molecular entities in pure as well as mixed states along with observations inferred from IR data of the studied mixtures. The VE, \(\kappa_{\text{S}}^{\text{E}}\), HE and \(C_{\text{P}}^{\text{E}}\) values estimated by Graph theory are in agreement with experimental values.