Acoustic and Refractive Behaviour of the Binary Mixture of 1-butyl-3 Methylimidazolium Tetrafluoroborate with 1-Alkanol at 298.15 to 313.15k

Densities, refractive indices and speeds of sound and their excess properties for 1-butyl-3-methylimidazolium tetrafluoroborate [Bmim][BF4] with 1-pentanol over the entire range of mole fraction are reported at temperatures ranging from 298.15 K to 313.15 K and atmospheric pressure. Isentropic and excess isentropic compressibility for ionic liquids with 1-alcohols were calculated from the experimental results. The excess values are fitted to the Redlich-Kister polynomial equation to estimate the binary coefficients and standard error between the experimental and calculated values. The measured speeds of sound were compared to the values obtained from Schaaffs' collision factor theory, Jacobson's intermolecular free length theory of solutions and Nomoto's relation. In addition, the experimentally obtained refractive indices were compared to the calculated values using Lorentz- Lorenz, Dale-Gladstone and Eykman mixing rules. The theoretical results obtained from these relations fairly agrees within the experimental precision. Further, the molecular interactions involved in IL binary mixture system were studied.