The thermodynamic characteristics of vaporization of propyl tert-butyl ethers

The boiling points of n-propyl tert-butyl and iso-propyl tert-butyl ethers were determined by comparative ebulliometry at moderate vapor pressures of 13.4-99.6 kPa. The temperature dependences of vapor pressures and the enthalpies of vaporization were obtained. The densities of the ethers in the temperature range 293-303 K were measured, The normal boiling temperatures, the enthalpies of vaporization at 298 K, and the critical parameters of the ethers (T-cr, p(cr) and V-cr) were calculated. The enthalpies of vaporization at 298.15 K determined calorimetrically and calculated from the vapor pressure data were in agreement with each other within measurement errors. The critical parameters were used to calculate the heat conductivity, viscosity, and surface tension of the ethers by the principle of corresponding states. The octane number of n-propyl tert-butyl ether was measured by the motor method and found to be 108.