Vaporization enthalpies of self-associated aromatic compounds at 298.15 K: a review of existing data and the features of heat capacity correction. Part II. Anilines

Abstract

Due to the low volatility, hygroscopicity, oxidation on air exposure, and association in the vapor-phase, the experimental study of the phase transition thermochemistry of hydrogen-bonded aromatic compounds, particularly amines, is complicated. As such, the available literature data is often scattered. In this respect, the critical analysis and reconciliation of the independent experiments performed at different temperatures are well merited.In this work, two goals were set. The first goal was to obtain a reliable dataset of the vaporization enthalpies for aniline and its derivatives at the reference temperature of 298.15 K. Second, we aimed to develop an approach for the estimation of the temperature dependence of their vaporization enthalpies. For these purposes, we collected the independent measurements of the vaporization, fusion, and sublimation enthalpies at different temperatures, as well as the heat capacities of the compounds in liquid, crystalline, and ideal gas states, required to adjust the phase transition enthalpies to 298.15 K. Possible non-ideality of the gaseous phase at elevated temperatures and pressures was accounted for to avoid systematic errors. Reconciliation of the collected data enabled to derive a set of consistent vaporization enthalpies of 22 compounds at 298.15 K and propose an approach for adjusting the vaporization enthalpies of aniline derivatives to an arbitrary temperature with an accuracy comparable to that of a direct experimental measurement.