THERMODYNAMICS OF LIQUID PROPANE PLUS CYCLOPROPANE

The vapour pressure differences between a mixture of (propane + cyclop ropane) and cyclopropane and between propane and cyclopropane have bee n measured simultaneously with the absolute vapour pressure of cyclopr opane. This was done at 13 temperatures between 175 K and 210 K, as a function of composition. The mixtures show small positive deviations f rom Raoult's law. The excess molar Gibbs energy (G(m)(E)) has been cal culated from the vapour pressure data and fitted to the equation G(m)( E)/(RTx(1)x(2) = (-0.2490 +/- 0.0072) + (81.8 +/- 1.4)/T. The estimate d value of the excess molar enthalpy (H-m(E)) for the equimolar compos ition, in the same temperature range is 170 +/- 4 J mol(-1). The resul ts were interpreted using Deiters' equation of state. (C) 1997 Elsevie r Science B.V.