Ultrasonic and dielectric behaviour of binary systems of quinoline with methylene chloride, chloroform, carbon tetrachloride, benzene and cyclohexane

Abstract

Ultrasonic velocities, u, and isentropic compressibilities, κ_s, have been measured for binary mixtures of quinoline (C₉H₇N) with carbon tetrachloride (CCl₄), benzene (C₆H₆) and chloroform (CHCl₃) at 303.15 and 313.15 K, for mixtures of C₉H₇N with methylene chloride (CH₂Cl₂) at 293.15 and 303.15 K, and for mixtures of C₉H₇N with cyclohexane (c-C₆H₁₂) at 303.15 K. Measurements of relative permittivities, ε, and refractive indices, n, have also been made for binary mixtures of C₉H₇N with CCl₄, CHCl₃, CH₂Cl₂, C₆H₆ and c-C₆H₁₂ at 303.15 K. The quantities Δκ_s and Δε which refer, respectively, to the deviations of the isentropic compressibilities and relative permittivities of the mixtures from the values arising from the mole-fraction mixture law, have been calculated. Δκ_s is negative throughout the whole range of composition in each case. Δε is large and positive for mixtures of C₉H₇N with CHCl₃ and CH₂Cl₂, practically zero at low mole fractions of C₉H₇N and small and positive for high mole fractions in the case of C₉H₇N–CCl₄ and C₉H₇N–C₆H₆. For C₉H₇N–c-C₆H₁₂, Δε is very slightly negative at low mole fractions of C₉H₇N and very slightly positive for high mole fractions. The Kirkwood correlation parameter, g, as calculated from the data on ε and n, for C₉H₇N–CHCl₃ and C₉H₇N–CH₂Cl₂ was used to obtain Δg, which refers to the deviation of the Kirkwood correlation parameter of the mixture from the values arising from the mole-fraction mixture law. Δg is large and positive for these systems. The equilibrium constants K_f for the formation of a 1 : 1 complex of C₉H₇N with CHCl₃ and CH₂Cl₂, as calculated from the relative permittivity data, are in accord with the theory of Barriol and Weisbecker, which is based upon the electrostatic interactions of the solute with the liquid. The apparent dipole moments, µ_app, of C₉H₇N in CCl₄ and C₆H₆ have been calculated. Δε, Δg and K_f show that C₉H₇N forms strong complexes with CHCl₃ and CH₂Cl₂, and that the interaction of C₉H₇N is stronger with CHCl₃ than that with CH₂Cl₂. Δε and µ_app show that there is a specific interaction of C₉H₇N with CCl₄ and C₆H₆, being stronger with CCl₄ than that with C₆H₆.