Measurement of Thermodynamic Functions of Solid Phase for DD, DF, OCDD and OCDF, and Estimation of Thermodynamic Functions of Gas Phase for PCDD/Fs Using Molecular Orbital Method with Density Functional Theory

Abstract

In this study, heat capacities of solid phase, melting points and enthalpies of fusion for DD, DF, OCDD and OCDF were measured by a modulated differential scanning calorimeter. Thermodynamic functions of gas phase such as heat capacity, entropy and standard enthalpy of formation for PCDD/Fs were calculated by the molecular orbital method with density functional theory, which is viewed as the one of the most accurate methods at present. The temperature dependences of enthalpies of formation for DD, DF, OCDD and OCDF can be estimated in the range from the solid phase to the gas phase using the data obtained in this study and reference data.