The standard (p degrees = 0.1 MPa) molar enthalpies of formation in the condensed phase, Delta H-f degrees(m) (cr, I), for 2',4'-, 2',5'-, and 3',4'-dichloroacetophenones were derived from the standard molar energies of combustion. Delta U-c degrees(m), in oxygen, to yield CO2(g) and HCl center dot 600H(2)O(1), at T = 298.15 K, measured by rotating bomb combustion calorimetry. The standard molar enthalpies of vapourization or sublimation, Delta H-g(cr,I)degrees(m) 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 Delta H-f degrees(m)(cr, I) and Delta H-g(cr,I)degrees(m). the standard molar enthalpies of formation of the three isomers, in the gaseous phase, Delta H-f degrees(m)(g), at T = 298.15 K were derived and compared with the same parameters estimated by the Cox Scheme. [GRAPHICS] (C) 2010 Elsevier Ltd. All rights reserved.