Experimental and computational studies on the molecular energetics of chlorobenzophenones.
The standard (p degrees = 0.1 MPa) molar enthalpies of formation, Delta(f)H(m)degrees, of crystalline 2-, 3- and 4-chlorobenzophenone and 4,4'-dichlorobenzophenone were derived from the standard molar energies of combustion, Delta(c)U(m)degrees, in oxygen, to yield CO(2)(g), N(2)(g), and HCl x 600H(2)O(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, Delta(cr)(g)H(m)degrees, 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 Delta(f)H(m)degrees and Delta(cr)(g)H(m)degrees, the standard molar enthalpies of formation of all the compounds, in the gaseous phase, Delta(f)H(m)degrees (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.
da Silva
Manuel A V Ribeiro
MA
Centro de Investigação em Química, Department of Chemistry, Faculty of Science, University of Porto, Rua do Campo Alegre, 687, P-4169-007, Porto, Portugal. risilva@fc.up.pt
Amaral
Luísa M P F
LM
Gomes
José R B
JR
D001577:Benzophenones / Q000737:chemistry*; D006843:Hydrocarbons, Chlorinated / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D013816:Thermodynamics
D001577:Benzophenones; D006843:Hydrocarbons, Chlorinated