Synthesis and analytical characterization of all tetra to octachlorodibenzo-p-dioxins

Abstract

We describe the synthesis and analytical characterization of the tetrachlorodibenzo-through octachlorodibenzo-p-dioxins. We determined the relative response factors for each chlorinated dioxin by both electron impact (EI) and negative chemical ionization mass spectrometry (NCI). An assumption of a 1:1 response factor for a polychlorinated dibenzo-p-dioxin (PCDD) congener within a group with the same number of chlorines is valid in EI but is not a valid assumption in NCI. We have determined the proton nuclear magnetic resonance chemical shift and coupling constants for each PCDD. All of the tetrachlorinated through heptachlorinated congeners, with two exceptions, gave appropriate first order proton spectra in Benzene-d 6. The vapor phase infrared absorption bands are unique for each PCDD congener and allow a second method of structural assignment.