Abstract: The excess enthalpies of α-pinene+p-cymene and β-pinene+p-cymene binary systems were determined at 298.15 K, 308.15 K and 318.15 K and at atmospheric pressure by using a Calvet microcalorimeter (BT2.15). The experimental excess enthalpy data were correlated with Redlich-Kister equation and the standard deviations were all very small. It was found that all the excess enthalpies of these two binary systems were positive in the range of the experimental concentrations and reach their maxima when the mole concentration x1 was about 0.5. The excess enthalpies were larger at the higher mixing temperatures. At the same temperatures, the excess enthalpies of α-pinene+p-cymene system were larger than that of β-pinene+p-cymene.

Key words: α-Pinene, β-Pinene, p-Cymene, Excess enthalpy, Microcalorimeter