Vapor−Liquid Equilibria for Pentane + Dodecane and Heptane + Dodecane at Low Pressures

A Fischer recirculating still has been used to measure isobaric vapor−liquid equilibrium data for pentane + dodecane and heptane + dodecane at 70 and 100 kPa and 40, 70, and 100 kPa, respectively. The concentrations of the vapor and liquid mixtures have been determined with the aid of an oscillating tube densimeter. The excess volume behavior has also been found on the basis of density−composition calibration curves. Vapor pressure data of the pure components as function of the temperature have also been measured and indicated the reliability of the experimental procedure. Thermodynamic consistency tests of the vapor−liquid data have been checked using a maximum likelihood data reduction and the UNIQUAC model.