Vapour pressure and enthalpy of vaporization of di-iso-propyl and di-tert-butyl esters of dicarboxylic acids

Molar enthalpies of vaporization of the branched aliphatic alkyl esters of dicarboxylic acids R-CO2-(CH2)n-CO2-R with n = (0–4) with R = iso-C3H7, tert-C4H9 were obtained from the temperature dependence of the vapour pressure measured by the transpiration method. These experimental results were checked for internal consistency and compared with the data available from the literature. A linear correlation of enthalpies of vaporization ΔlgHm (298.15 K) of the alkyl esters of dicarboxylic acids with the number of carbon atoms, as well as with the Kovat's indices on the low-polar GC column has been found.

► We measured vapour pressure of i-Pr and t-Bu esters R-CO2-(CH2)n-CO2-R with n = 0–4.
► Molar vaporization enthalpies at 298 K were derived.
► We examined consistency of new and available in the literature data.
► Enthalpies of vaporization show linear dependence on numbers n.
► Enthalpies of vaporization correlate linearly with Kovat's indices.