Excess molar volumes and speeds of sound of tetrahydrofuran with chloroethanes or chloroethenes at 298.15 K

Abstract

Excess molar volumes,

and speeds of sound, u of the binary liquid mixtures of tetrahydrofuran (THF) with chloroethanes or chlororethenes at 298.15 K have been measured over the entire range of (THF) compositions. The chloroethanes are 1,2-dichloroethane, 1,1,1-trichloroethane, and 1,1,2,2-tetrachloroethane and the chloroethenes are trichloroethylene and tetrachloroethylene. Partial molar volumes

, were also calculated and their values have been extrapolated to zero concentration to obtain the limiting values at infinite dilution,

. The

values are negative in mixtures of THF + tetrachloroethylene, + trichloroethylene, + 1,1, 1-trichloroethane, and + 1,1,2,2-tetrachloroethane over the entire composition range of THF. The

values are positive for THF with 1,2-dichloroethane. An inversion of the sign of

was observed at x ≈ 0.75 of THF for the mixtures of THF with 1,2-dichloroethane. Further, isentropic compressibilities, k _s of the mixtures were computed by combining speeds of sound and density data. Deviation in isentropic compressibility, Δk _s were evaluated using volume fraction ϕ weighing of the individual component properties to estimate ideal mixture behaviour. The Δk _s values are negative over the whole of volume fraction for all the mixtures except for 1,2-dichloroethane. The Δk _s values were positive over the entire volume fraction of THF with 1,2-dichloroethane. For all systems,

and Δk _s values were satisfactorily correlated by the Redlich–Kister polynomial. The results are explained in terms of dissociation of the self-associated chloroethanes or chloroethene molecules and the formation of aggregates between unlike molecules.

Keywords:

• Excess molar volumes
• Speeds of sound
• Isentropic compressibility
• Redlich−Kister
• Tetrahydrofuran (THF)

Acknowledgements

The authors thank the university authorities for providing the necessary facilities to carry out the work and thanks are due to Mr. Samei for his help with the manuscript.