An Insight on Thermophysical Properties of Binary Mixtures of Hydrocarbons with Spectroscopic Evidence; Essential Components of Transformer Oils

Abstract

The aim of the present investigation is to analyze the effect of carbon chain length in benzene + (hexane/heptane) binary mixtures at different temperatures through density (ρ), ultrasonic velocity (U), viscosity (η) and dielectric (ε) measurements. Derived properties such as molar volume (V), isentropic compressibility (βs), acoustic impedance (Z) and intermolecular free length (Lf) have been calculated for T = 298.15, 308.15 and 318.15K. The excess values of the above mentioned properties of the binary mixtures of benzene + (hexane/heptane) are determined at different temperatures and have been fitted to Redlich – Kister polynomial equation. The dielectric permittivity results demonstrate that deviations from pure components are mostly negative in both the mixtures except for few cases in benzene rich region. Excess Gibb’s free energy of activation of viscous flow (GE) has been calculated using the viscosity measurements at different temperatures. Mixing rules have been adopted to calculate the ultrasonic velocities of the binary mixtures of benzene + (hexane/heptane) at the above said temperatures. FT-IR and NMR analysis have been done to check the accuracy of the results.