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Experimental and computational thermochemical study of the tri-, tetra-, and pentachloronitrobenzene isomers

2009; Elsevier BV; Volume: 41; Issue: 9 Linguagem: Inglês

10.1016/j.jct.2009.03.014

1096-3626

Manuel A.V. Ribeiro da Silva, Ana I.M.C. Lobo Ferreira, Joana I.T.A. Cabral, Ana Filipa L.O.M. Santos, Ana Rita G. Moreno, Tiago L. P. Galvão, Inês M. Rocha, Paula M. V. Fernandes, Sílvia Q. Salgueiro, Vanessa A.F. de Moura, Isabel S. Oliveira, Paula C. Cotelo, Mariana Ribeiro,

Thermal and Kinetic Analysis

The standard (p∘=0.1MPa) molar enthalpies of formation of 2,4,6-trichloronitrobenzene, 2,3,5,6-tetrachloronitrobenzene, and pentachloronitrobenzene, in the crystalline state, at T = 298.15 K, were derived from the standard massic energies of combustion, in oxygen, at T = 298.15 K, measured by rotating-bomb combustion calorimetry. The standard molar enthalpies of sublimation, at T = 298.15 K, of 2,4,6-trichloronitrobenzene and pentachloronitrobenzene, were determined from the dependence with the temperature of the vapour pressures, measured by the Knudsen mass-loss effusion method, whereas for 2,3,5,6-tetrachloronitrobenzene, the Calvet drop microcalorimetric technique was used.Empty Cell-ΔcUm∘(cr)/(kJ · mol−1)-ΔfHm∘(cr)/(kJ · mol−1)ΔcrgHm∘/(kJ · mol−1)2,4,6-Trichloronitrobenzene2663.5 ± 1.158.6 ± 1.386.7 ± 1.12,3,5,6-Tetrachloronitrobenzene2537.1 ± 1.767.0 ± 1.991.3 ± 2.5Pentachloronitrobenzene2387.4 ± 2.498.6 ± 2.594.5 ± 0.4 The experimental values are also compared with estimates based on G3(MP2)//B3LYP computations, which have also been extended to all the isomers of the trichloro- and tetrachloronitrobenzene that were not studied experimentally.