Thermal properties of dioxins, furans and related compounds

Abstract

Vapor pressures are important parameters for modeling of environmental fate and incineration behaviour of chloro-dibenzodioxins and -dibenzofurans. Vapor pressures, enthalpies and entropies of sublimation were measured for four dibenzofurans and were compared to corresponding data on chlorodioxins. A vapor pressure correlation method, which uses the liquid phases as reference states was introduced. Boiling points, enthalpies and entropies of fusion could be calculated from the vapor pressure data by this method. The determined parameters were correlated with the degree of chlorine substitution and the correlations permit the estimation of boiling points, enthalpies of fusion and of sublimation pressures of n-chlorodioxins and -furans of known melting points. The predicted vapor pressures of 2,3,7,8-TCDD were found to be in good agreement with literature reportings.