Isothermal and Isobaric Vapor Liquid Equilibrium and Excess Molar Enthalpy of the Binary Mixtures of 2-Methoxy-2-methylpropane+2-Methyl-2-butanol or+2-Butanol

Low molecular weight ethers have been used for many years as enhancers for fossil fuels combustion. A gradual replacement of mineral oils by bio-oils requires additional knowledge about the thermodynamic properties of bio-alcohol and ether mixtures. In this work, isothermal vapor liquid equilibria (VLE) of the binary mixture of methyl tert-butyl ether (MTBE, 2-methoxy-2-methylpropane) with 2-methyl-2-butanol and MTBE with 2-butanol were measured isothermally at 323 K and at constant 90.1 kPa pressure with a recirculation still apparatus. Excess molar enthalpy (h(E)) was measured for two binary mixtures at 308 K, 323 K, and 363 K by using a SETARAM C80 calorimeter equipped with a flow mixing cell. A comprehensive consistency analysis was performed for the obtained data, and the experimental data were correlated with the nonrandom two liquid and universal quasichemical activity coefficient models. The results were compared with UNIFAC-Dortmund and COSMO-RS predictive models. The investigated mixtures are close to ideal and show small positive deviation from Raoult's law. Calorimetric measurements show large positive molar excess enthalpy that decreases with the temperature for both investigated binary mixtures.