Vapour pressure determination for dibenzo-p-dioxin, dibenzofuran, octachlorodibenzo-p-dioxin and octachlorodibenzofuran using a Knudsen effusion method

A new apparatus with Knudsen effusion method especially designed for the vapour pressure measurements of dioxin congeners and other POPs is described. Crystalline benzoic acid and anthracene were first used to test the new designed apparatus. The vapour pressure and enthalpy results of the two reference compounds were found in good agreement with accepted literature data. The vapour pressure and enthalpy results of crystalline DD, DF, OCDD and OCDF determined with the new apparatus are presented, and compared with the literature data measured with other methods.