Vapor–liquid equilibria and excess properties of octane + 1,1-dimethylpropyl methyl ether (TAME) mixtures

Abstract

Vapor–liquid equilibrium (VLE) data are reported for the binary mixtures formed by octane and the branched ether 1,1-dimethylpropyl methyl ether ( tert-amyl methyl ether or TAME). A Gibbs–van Ness type apparatus was used to obtain total vapor pressure measurements as a function of composition at 298.15, 308.15, 318.15 and 328.15 K. The system shows positive deviations from Raoult’s law. These VLE data are analyzed together with data previously reported for octane+TAME mixtures: VLE data at 323.15 and 423.15 K, excess enthalpy ( H m E) data at 298.15 and 313.15 K and excess volume ( V m E) data at 298.15 K. The UNIQUAC model, the lattice–fluid (LF) model, and the Flory theory are used to simultaneously correlate VLE and H m E data. The two latter models are then used to predict V m E data. The original UNIFAC group contribution model and the modified UNIFAC (Dortmund model) are used to predict VLE data.