Isentropic Compressibility Δκs Research Articles

Ultrasonic study of molecular interaction in binary liquid mixtures at 30°C

Densities ρ and ultrasonic speeds u of the binary mixtures of tetrahydrofuran (THF) with 1-butanol and tert-butanol, at 30°C, over the entire composition range were measured. From these data isentropic compressibility, K s, intermolecular free length L f, relative association R A, acoustic impedance Z, molar sound speed R m, deviations in isentropic compressibility ΔK s, and excess volume V E were calculated. The variation of these parameters with composition of the mixture helps us in understanding the nature and extent of interaction between unlike molecules in the mixtures. Further, theoretical values of ultrasonic speed were evaluated using theories and empirical relations. The relative merits of these theories and relations were discussed.

Density, Refractive Index, Viscosity, and Speed of Sound in Binary Mixtures of Cyclohexanone with Hexane, Heptane, Octane, Nonane, Decane, Dodecane, and 2,2,4-Trimethylpentane

Experimental results of density, refractive index, and viscosity at 298.15, 303.15, and 308.15 K and the speed of sound at 298.15 K are presented for the binary mixtures of cyclohexanone with n-alkanes (C6−C12) or 2,2,4-trimethylpentane over the entire range of mixture composition scale. From these data, excess molar volume VE, deviations in molar refraction ΔR, viscosity Δη, speed of sound Δu, and isentropic compressibility ΔkS have been calculated. These results are further fit to the Redlich and Kister (1948) polynomial equation to derive the binary coefficients and standard deviations between the calculated and the fit parameters. Furthermore, these results are used to study the nature of intermolecular interactions between the mixing components. All the properties have shown a systematic dependence on the chain length of alkanes.