Measurement and Prediction of Properties for Mixtures of Vegetable Oils + Hexane at Different Temperatures

Abstract

The present study aimed to evaluate the effect of temperature, composition, and type of vegetable oil on the properties of mixture hexane + vegetable oil. Experimental data of densities for mixtures of vegetable oils (canola, soybean, and sunflower) with hexane were measured at temperatures between 293.15 and 323.15 K in order to evaluate the excess volume profiles of each system. Predictive and adjusted equations were used to compare the results and evaluate models. The thermodynamic properties of the mixture (excess Gibbs free energy, entropy, and enthalpy ( G ex, S ex, and H ex, respectively)) were determined and evaluated. All volume profiles presented a negative behavior, and the increase in this effect was observed when the temperature was increased; also, it was noted that the most unsaturated vegetable oils suffered a greater influence of temperature on their volumetric profiles. Prediction models showed good agreement with the experimental data of the literature. The G ex profiles presented a negative behavior in all cases, while the S ex and H ex profiles were positive. In general, large differences were not observed between the profiles of G ex, S ex, and H ex for the studied mixtures of hexane and vegetable oils.

Effect of temperature on the physical properties’ density, viscosity, and refractive index of babassu (Orbignya sp.) oil in the range between 293 and 333 K

“…Ceriani et al (2007) The density (mass/volume) of the two brands of babassu oil was inversely proportional to the temperature. This result was already expected, because the increase in temperature increases the kinetic energy of the system, and thus, the triacylglycerol molecules orient themselves more distant from each other, causing a kind of disaggregation, which consequently increases the volume occupied by the molecule; as the density is inversely proportional to the volume, its values tend to decrease (Costa;Pereira, 2020).…”