Vapor-liquid equilibria of binary mixtures of n-heptane with 1,1-dimethylpropyl methyl ether and 1,1-dimethylethyl methyl ether

Vapor-liquid equilibrium data are reported for the binary mixtures formed by n-heptane and the branched ethers 1,1-dimethylpropyl methyl ether (tert-amyl methyl ether or TAME) and 1,1-dimethylethyl methyl ether (tert-butyl methyl ether or MTBE). A Gibbs-Van Ness type apparatus was used to obtain total vapor pressure measurements for n-heptane-MTBE and n-heptane-TAME mixtures at 298.15 and 308.15 K. The systems show very small positive deviations from Raoult's law with a nearly ideal behavior. Results are analyzed in terms of the Peng-Robinson equation of state and the Wong-Sandler mixing rule, the Lattice-Fluid (LF) model, the UNIQUAC model, and several versions of the UNIFAC model.