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Experimental and Computational Studies on the Molecular Energetics of Chlorobenzophenones

2007; American Chemical Society; Volume: 111; Issue: 45 Linguagem: Inglês

10.1021/jp076522j

1520-6106

Manuel A.V. Ribeiro da Silva, Luı́sa M.P.F. Amaral, José R. B. Gomes,

Thermal and Kinetic Analysis

The standard (p° = 0.1 MPa) molar enthalpies of formation, , of crystalline 2-, 3- and 4-chlorobenzophenone and 4,4‘-dichlorobenzophenone were derived from the standard molar energies of combustion, , in oxygen, to yield CO2(g), N2(g), and HCl·600H2O(l), at T = 298.15 K, measured by rotating bomb combustion calorimetry. The Calvet high-temperature vacuum sublimation technique was used to measure the enthalpy of sublimation, , of the compound 2-chlorobenzophenone. For the other three compounds, the standard molar enthalpies of sublimation, at T = 298.15 K were derived by the Clausius−Clapeyron equation, from the temperature dependence of the vapor pressures of these compounds, measured by the Knudsen-effusion technique. From the values of and , the standard molar enthalpies of formation of all the compounds, in the gaseous phase, (g), at T = 298.15 K, were derived. These values were also calculated by using the B3LYP/6-311+G(2d,2p)//B3LYP/6-31G(d) computational approach.