Transpiration method: Vapor pressures and enthalpies of vaporization of some low-boiling esters

Abstract

This investigation was undertaken to reveal the upper limit of vapor pressures which could be measured by using the transpiration method accurately. Molar enthalpies of vaporization of 10 esters of monocarboxylic acids were obtained from the temperature dependence of the vapor pressure measured by the transpiration method. The measured data sets were successfully checked for internal consistency. A large number of the primary experimental results on temperature dependences of vapor pressures have been collected from the literature and have been treated uniformly in order to derive vaporization enthalpies at the reference temperature 298.15 K. Comparing our experimental vapor pressures with those from literature we have assessed the pressure range of 5000–7000 Pa as the upper limit of vapor pressure, at which it is still possible to measure properly using the transpiration method.