Enthalpies of formation and entropies of chlorinated dibenzo-p-dioxins and dibenzofurans; selected data for computer-based studies

Thermodynamic Properties of Dibenzo-p-dioxin, Dibenzofuran, and Their Polychlorinated Derivatives in the Gaseous and Condensed Phases. 1. Thermodynamic Properties of Gaseous Compounds

“…The latter interactions were assumed to be the same as those in chlorinated phenols. However, the semiempirical calculations Fokin et al, 1989), the recent estimations by additivity method (Thompson, 1994a(Thompson, , 1995Dorofeeva and Gurvich, 1996) (Table 1) and predictions of relative concentrations of chlorinated dioxins and dibenzofurans (Thompson, 1994b;Unsworth and Dorans, 1993) indicate that Shaub's model is unsatisfactory. Because of strong oxygen-chlorine interactions suggested in this model, the value of the enthalpy of formation of 2,3,7,8tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) is found to be much less (-345 kJ‚mol -1 ) than that estimated by other methods (from -160 to -190 kJ‚mol -1 ; see Table 1).…”

“…To estimate the gas-phase enthalpies of formation of PCDDs and PCDFs, Thompson (1995) developed a group contribution method based on the experimental data for chlorinated benzenes, quinones, hydroquinones, and phenols. Pointing at often considerable uncertainties of the experimental enthalpies of formation for chlorinated organic compounds, Thompson (1995) excluded the experimental data of Platonov and Simulin (1983 from consideration.…”

“…To estimate the gas-phase enthalpies of formation of PCDDs and PCDFs, Thompson (1995) developed a group contribution method based on the experimental data for chlorinated benzenes, quinones, hydroquinones, and phenols. Pointing at often considerable uncertainties of the experimental enthalpies of formation for chlorinated organic compounds, Thompson (1995) excluded the experimental data of Platonov and Simulin (1983 from consideration. At the same time Thompson (1995) included the value of ∆ f H°(298.15 K) for hexachlorobenzene recommended by Pedley (1994) (Table 2), although this value would not seem quite accurate and possibly was overestimated.…”

A Thermochemical Parameters and Theoretical Study of the Chlorinated Compounds of Thiophene

“…Based on the û o 298 of chlorobenzene (13.01 ± 0.50 kcal/mol) [26], benzene (19.8 ± 0.2 kcal/mol) [27], thiophene (52.20 kcal/mol) [28], and the û o 298 for the selected chlorothiophene compounds were estimated using CBS-QB3 along with the selected isodesmic reaction Scheme 2 (Table 2).…”

Thermodynamics of dibenzo-p-dioxin and 1,2,3,4-tetrachlorodibenzo-p-dioxin fromT= 5 K toT= 490 K

“…However, experimental thermodynamic data for PCDD are quite scanty in the scientific literature. Before 1996, only approximate estimates of f H o m (g) were reported; (2)(3)(4)(5)(6)(7) in reference 2, the f H o m (g) values were evaluated for all 75 compounds PCDD congeners. Later, Kolesov and colleagues (8)(9)(10)(11) determined the enthalpy of combustion at T = 298.15 K of crystalline dibenzo-p-dioxin (DBD) in a calorimeter with a stationary bomb and that of crystalline 1-chlorodibenzo-p-dioxin (1-CDD), 2-chlorodibenzo-p-dioxin (2-CDD), and 2,3-dichlorodibenzo-p-dioxin (2,3-CDD) in a calorimeter with a rotating bomb.…”