No abstract

The kinematic viscosity was measured for binary and ternary liquid mixtures for the hexadecanoic, octadecanoic, and cis-9-octadecenoic acids, at temperatures ranging from above the solidification point up to 373 K using a Cannon Fenske three-capillary viscosimeter. The measurements were correlated with Andrade's equation for pure components, with McAllister's equation for binary and ternary mixtures, and with Teja and Rice's equation for ternary mixtures. A nearly lineal behavior of the kinematic viscosity with regard to composition was observed in the above-mentioned equations for all the tested mixtures. The equations gave a satisfactory fit to the kinematic viscosity of the liquid mixtures studied. For ternary mixtures, Teja and Rice's equation permitted their estimation over a higher temperature range than McAllister's equation.

The heat capacities in the liquid phase of the fatty acids hexadecanoic acid, octadecanoic acid, and cis-9-octadecenoic acid were measured, as well as those of their binary and ternary mixtures from temperatures close to solidification to 528 K. The measurements were correlated and contrasted with equations, methods, and values for the pure fatty acids, Ruzicka and Domalski's method providing better results for most of the temperature range studied. For binary and ternary mixtures, molar fraction average and corresponding states methods were used. The convenience of the former with respect to the latter was demonstrated; it is easier to apply and provides suitable results. Furthermore, in the case of the mixtures, only slight variations in heat capacity with composition were experienced. All the measurements were carried out using a DSC differential scanning calorimeter.