Calculation of thermodynamic parameters of 75 gaseous PCDDs using the density functional theory

摘要

In this paper,the thermodynamic parameters are calculated for all gaseous Poly Chlorinat Dibenzo-p-dioxins (PCDDs)using the Density Functional Theory(DFT)method and both the enthalpy of formation(Δ_fH^o)and Gibbs free energy of formation(Δ_fG^o)are derived,from which the order of stability of individual congeners is then predicted.All these properties,together with the calculated entropies(S^o)and heat capacities(C_p),are presented as a function of the number of chlorine atoms in the various PCDD molecules.The accuracy of the method used here,is evaluated by comparing the thermodynamic parameters of gaseous chlorobenzenes with experimental values collected from literature.