CuCl 2-catalyzed PCDD/F formation and congener patterns from phenols

Abstract

Homologue and isomer patterns of polychlorinated dibenzo- p-dioxin (PCDD) and polychlorinated dibenzofuran (PCDF) in CuCl 2-catalyzed formation were studied in an isothermal flow reactor using a distribution of 20 phenols as measured in municipal waste incinerator (MWI) exhaust gases. A mixture of 20 phenols was synthesized and used as reactants for this study because phenols are known to be key precursors in the formation of PCDD/F. Experiments were conducted at 400 °C. The 92% of nitrogen (N 2) and 8% of oxygen (O 2) were used as a carrier gas. PCDD/F homologue and isomer patterns with dibenzo- p-dioxin (DD) and dibenzofuran (DF) were obtained from a mixture of 20 phenols. DF + PCDF formation was favored over DD + PCDD formation. The major homologue groups formed were non-chlorinated DD and DF, and PCDD/F homologue fraction decreased with the degree of chlorination. PCDD/F homologue and isomer distributions were almost constant. Phenol and lower chlorinated phenols present in high amount played an important role in PCDD/F congener distributions. The results presented here can be used as characteristics or fingerprints for homologue and isomer patterns of PCDD/F formation attribution in CuCl 2-catalyzed reaction from phenols.