The equilibrium phase properties of the propane-methanol and n-Butane-methanol binary systems

Vapor and liquid equilibrium phase compositions were determined at 310.7, 352.2, 393.0 and 474.3 K for the propane-methanol system and at 469.9 K for the n-butane–methanol system. Measurements were made at pressures from the vapor pressure of the less volatile component to the maximum pressure where two phases coexisted either as an azeo-trope or at the critical condition, depending on the system. Azeotropic behavior was observed at 310.7 and 352.2 K for the propane-methanol system. Equilibrium ratios were calculated at each temperature from the phase composition data. The temperature dependence of the azeotrope pressure and of the corresponding azeotrope composition was expressed analytically.