Thermodynamic properties of mixtures containing 1-butyl-2,3-dimethylimidazolium tetrafluoroborate and cyclopentanone or cyclohexanone

The densities, ρ, speeds of sound, u, and molar heat capacities, CP, of 1-butyl-2,3-dimethylimidazolium tetrafluoroborate (1) + cyclopentanone or cyclohexanone (2) mixtures at 293.15, 298.15,303.15 and 308.15 K and excess molar enthalpies, HE of same mixtures at 298.15 K have been measured as a function of composition. The observed ρ, u, and CP values are used to determine excess molar volumes, VE, excess isentropic compressibilities, κSE and excess heat capacities, CPE. The analysis of VE data in terms of Graph theory has suggested that while 1-butyl-2,3-dimethylimidazolium tetrafluoroborate exists as monomer; cyclopentanone and cyclohexanone exist as mixture of open and cyclic dimer. The analysis of inter-nuclear distances among interacting atoms (predicted by quantum mechanical calculations) also supports the presence of proposed molecular entities in pure and mixed states. It has been observed that VE, κSE, CPE and HE estimated by Graph theory compare well with their experimental values.