Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

ABSTRACT

The standard (p = 0.1 MPa) molar enthalpies of formation in the condensed phase, for 2',4'-, 2',5'-, and 3',4' -dichloroacetophenones were derived from the standard molar energies of combustion in oxygen, to yield CO2(g) and HCl 600H2O(l), at T = 298.15 K, measured by rotating bomb combustion calorimetry. The standard molar enthalpies of vapourization or sublimation, of these compounds, at T = 298.15 K were determined by Calvet microcalorimetry. For the 3',4'-dichoroacetophenone, the standard molar enthalpy of sublimation, at T = 298.15 K, was derived by the Clausius-Clapeyron equation, from the temperature dependence of the vapour pressures of this compound, measured by the Knudsen effusion technique. From the values of standard (p = 0.1 MPa) molar enthalpies of formation in the condensed phase (cr,l) and standard molar enthalpies of vapourization or sublimation the standard molar enthalpies of formation of the three isomers, in the gaseous phase, at T = 298.15 K were derived and compared with the same parameters estimated by the Cox Scheme.