Second-order excess derivatives for the 1,3-dichloropropane + n-dodecane system

Abstract

An experimental study of the behaviour of the second-order excess derivatives against composition and temperature for the 1,3-dichloropropane+ n-dodecane system is presented. To this end, densities and speeds of sound were obtained in the interval 278.15–328.15 K with a step of 1 K. In addition, isobaric molar heat capacities were obtained in the temperature range 283.15–323.15 K. Measurements were performed over the whole composition range and at atmospheric pressure. Isentropic compressibilities were determined using the Laplace equation, and isobaric thermal expansivities were obtained in the interval 283.15–323.15 K from density data. Isothermal compressibilities and isochoric molar heat capacities within 283.15–323.15 K were derived from the above-mentioned properties via appropriate thermodynamic relations. The excess quantities for these properties were calculated using the ideality criterion first proposed by Benson and Kiyohara. Destruction of the 1,3-dichloropropane dipolar order during mixing appears to be the main effect to which the excess properties are sensitive.