Acoustical and thermodynamic study of binary mixture cyclohexane-methanol using ultrasonic interferometer at different temperatures

The ultrasonic velocity (U) mass density (ρ) and shear viscosity (η) of the binary liquid mixtures of cyclohexane-methanol have been determined experimentally in the single-phase region and over the whole composition range at temperature range (T = 321.15 to 325.15 K). The experimental measurements of these properties have been carried out at atmospheric pressure, for a constant frequency 2 MHz. From these experimental data values, various acoustic and thermodynamic parameters namely adiabatic compressibility (βs), acoustic impedance (Z), intermolecular free length (Lf), relaxation time (τ), molar volume (Vm), free volume (Vf), internal pressure (πi), attenuation (α/f2), Gibb’s energy (ΔG), and cohesive energy (CE) have been calculated. Also their excess values have been calculated. All these parameters and their excess values have been interpreted in terms of molecular interaction such as dipole-dipole and dipole induced dipole interactions through hydrogen bonding between components of binary liquid mixture

Tracer Diffusion of 65^{65}Zn2+^{2+} in Binary Isobutyric Acid + Water Mixtures Near the Critical Point

Tracer diffusion coefficients of $^{65}$Zn$^{2+}$ in mixtures of isobutyric acid water and $10^{-4}$ M ZnCl$_2$ have been measured over the composition range $0 < X < 95\%$ in acid; at $\theta_1 = T_1 -T_{\rm c} = 0.547$ K and $\theta_2 = T_2 - T_{\rm c} = 7.547$ K using the open-ended capillary method. The critical temperature was found to be: $T_{\rm c} = 27.453~^\circ$C. An important anomaly was detected in the neighbourhood of the critical point $X_{\rm c} = 0.38$, $X$ being the weight percentage of the acid. The concentration dependence as the shear viscosity coefficients were evaluated at each $X$ value for the same temperatures. The results are discussed in terms of Einstein-Stokes law. Our analysis suggests three different behaviours of the diffusing entity in the mixtures and it is based on the preferential solvation phenomenon

Electrical Conductivity along Phase Diagram of the Critical Mixture Isobutyric Acid – Water with Added (K+, Cl-) Ions

Three systems, isobutyric acid – water (I–W), “(I-W) + 5 10-4 M (KCl)” and “(IW) + 5 10-3 M (KCl)”, have been studied by measuring the electrical conductivity σ (Ω-1cm-1) along the coexistence curve in a single phase, as a function of the variations temperature T and composition X in acid. The coefficient σ is a temperature dependent parameter for ions, increasing as temperature is elevated. Contrary to the visconty, the electrical conductivity does not show any anomaly in the critical region

Electrical Conductivity along Phase Diagram of the Critical Mixture Isobutyric Acid – Water with Added (K +, Cl-) Ions

Abstract: Three systems, isobutyric acid – water (I–W), “(I-W) + 5 10-4 M (KCl) ” and “(I-W) + 5 10-3 M (KCl)”, have been studied by measuring the electrical conductivity σ (Ω-1 cm-1) along the coexistence curve in a single phase, as a function of the variations temperature T and composition X in acid. The coefficient σ is a temperature dependent parameter for ions, increasing as temperature is elevated. Contrary to the visconty, the electrical conductivity does not show any anomaly in the critical region