Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

ABSTRACT

The present work reports the values of the standard (p = 0.1 MPa) molar enthalpies of formation, in the crystalline phase, of 2-trichloroacetylpyrrole and 2-trifluoroacetylpyrrole, which were derived from the standard molar energies of combustion, in oxygen, to yield HCl 600H2O(l) and HF 10H2O(l), respectively, as well as CO2(g) and N2(g), at T = 298.15 K, measured by rotating bomb combustion calorimetry. The values of the standard molar enthalpies of sublimation, at T = 298.15 K, derived from the Knudsen mass-loss effusion technique are also presented. From the above mentioned experimental quantities, the standard molar enthalpies of formation, in the gaseous phase, were derived: (2-trichloroacetylpyrrole, g) = (102.5 +- 1.6) kJ mol 1 and (2-trifluoroacetylpyrrole, g) = (704.7 +- 3.0) kJ mol 1. These experimental values are compared with estimates based on high-level ab initio molecular orbital calculations at the G3(MP2)//B3LYP level, which have also been extended to the calculation of other thermodynamic properties namely N-H bond dissociation enthalpies, gas-phase acidities and basicities, proton affinities, and adiabatic ionization enthalpies.