Vapor-liquid equilibria of binary mixtures of alkanols with alkanes from atmospheric pressure to the critical point

Abstract

A reformulated version of the Wong-Sandler mixing rule and the Peng-Robinson equation of state are used for the correlation and prediction of the vapor-liquid equilibrium of several alkanol + alkane binary systems. The description of these mixtures provides a stringent test since cubic equations of state with conventional mixing rules usually predict false liquid-liquid splits for such systems. For all systems, the model parameters used were fit to data on the lowest-temperature isotherm and then higher-temperature isotherms were successfully predicted with those parameters. False phase splitting was avoided by using a constrained parameter fit. For highly asymmetric (in size) alkanol+alkane binaries four parameters were necessary for an accurate representation of the data, while for less asymmetric alkanol + alkane binaries only two parameters were used.