Thermochemistry of formation and phase transitions of substituted thiophenes at 298.15 K

Abstract

This study presented experimental vapour pressure data and thermochemical properties of phase transitions for five substituted thiophenes. Using the transpiration technique, the temperature dependencies of vapour pressure and corresponding enthalpies of vaporisation were determined. Additionally, fusion enthalpies and melting temperatures for 3-acetylthiophene and 2,2′-di-thiophene were measured with differential scanning calorimetry. The solution enthalpies of the substituted thiophenes in benzene were used to evaluate the vaporisation and sublimation enthalpies at 298.15 K. The results of this study were found to be consistent with the literature data, allowing for reliable data on the vapour pressure and enthalpies of vaporisation and sublimation to be evaluated. Furthermore, the evaluated vaporisation and sublimation enthalpies were applied to validate the literature values of condense and gas state formation enthalpies for the studied substituted thiophenes. Additionally, quantum-chemical computations of the gas-phase enthalpies of formation were carried out.