Measurement and correlation of vapor-liquid equilibria for the ethanol plus n-heptane system near the critical region

Isothermal VLE data for ethanol 4- n-heptane have been obtained at near-critical temperatures. The critical pressures determined from the critical opalescence of the mixtures were compared with published work for ethanol + n-butane, ethanol + n-pentane, and ethanol + n-hexane systems. A circulating type apparatus with a view cell has been used. These mixtures are highly nonideal because of the association of ethanol, and the data could be correlated with sufficient accuracy by using the Peng-Robinson-Stryjek-Vera (PRSV) equation of state with Wong-Sandler mixing rules.