Investigation of Some Physicochemical Properties of Mixtures of Morama Seed Oil with (C₆–C₉) n‐Alkanes at 298.15 and Atmospheric Pressure

Abstract

Densities q, ultrasonic speeds u and dynamic viscosities g, of mixtures of morama, Tylosema esculentum, seed oil with n-hexane, n-heptane, n-octane and n-nonane were determined over the entire composition range at 298.15 K and atmospheric pressure. Excess molar volumes, V E m , excess molar free volumes V E f , deviations in isentropic compressibility, Dj s , deviations in ultrasonic speed, Du, deviations in viscosity, Dg, and the excess free energy of activation of viscous flow, DG* E , were calculated therefrom and correlated by the Redlich-Kister equation for each of the [morama seed oil ? (n-hexane or n-heptane or n-octane or n-nonane)] mixtures. The results have been discussed in terms of possible intermolecular interactions and structural effects.

Physicochemical Properties of Mixtures of Morama Seed Oil With Alkanols and Alkyl Acetates at 298.15 K Atmospheric Pressure

“…The purity of the cosolvents was tested by comparing their densities, ρ , ultrasonic speed, u , and dynamic viscosities, η , at 298.15 K, with the reported literature data in Table , which also includes our measured values of these quantities. It was observed that the measured values of ρ , u , and η were in good agreement with the literature data (Aminabhavi et al, ; Aralaguppi et al, ; Gonzalez et al, , ; Yeboah et al, ). Ultra‐pure water used in the calibration of the interferometer and densimeter was obtained as described elsewhere (Yeboah et al, ).…”

“…It was observed that the measured values of ρ , u , and η were in good agreement with the literature data (Aminabhavi et al, ; Aralaguppi et al, ; Gonzalez et al, , ; Yeboah et al, ). Ultra‐pure water used in the calibration of the interferometer and densimeter was obtained as described elsewhere (Yeboah et al, ). All purified organic solvents were stored in brown glass bottles and fractionally distilled and ultrasonically degassed immediately before the preparation of binary mixtures.…”

“…The fatty‐acid composition obtained was as follows: oleic acid, 47.27%; linoleic acid, 23.40%; palmitic acid, 12.93%; stearic acid, 8.82%; arachidic acid, 3.31%; erucic acid, 2.63%; behenic acid, 1.03%; and arachidonic acid, 0.61%; the uncertainty in mol% obtained for these analyses was better than ±0.06. The calculated average molar mass of the MO used in this study was 850.34 ± 3 g mol −1 (Yeboah et al, ).…”

“…Solution density measurements were performed at atmospheric pressure with an Anton Parr DMA 4500 (Ashland, Virginia, USA) vibrating‐tube precision densimeter at 298.15 K. The densimeter was first calibrated with ultrapure water (Parr, ; Yeboah et al, ) as a reference liquid. A sample volume of not more than 1.0 cm 3 was needed to fill the densimeter cell and thermal equilibrium was achieved quickly at 298.15 K. The temperature of the sample was controlled electrically by means of a built‐in thermostat (a semiconductor Peltier element and a resistance thermometer temperature control system) and was measured with an accuracy of ±0.01 K. The densimeter was calibrated after each set of four sample measurements to offset any problem of instrument drift.…”

“…Measurements of such properties are also useful for developing correlations for a specific system. We have recently reported the excess molar volumes, isentropic compressibility, and dynamic viscosities for mixtures of MO with n ‐hexane or n ‐heptane or n ‐octane or n ‐nonane at 298.15 K and atmospheric pressure (Yeboah, Oathotse, & Ddamba, ). These investigations revealed a significant deviation from the ideal solution behavior, which was attributed to structural effects.…”