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CuCl2-catalyzed PCDD/F formation and congener patterns from phenols.
Jae-Yong Ryu1, James A Mulholland, Masao Takeuchi
1Combustion Control Group, Energy Technology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 16-1 Onogawa, Tsukuba, Ibaraki 305-8569, Japan. jaeyong.ryu@aist.go.jp
Chemosphere
|June 1, 2005
Summary
Polychlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF) formation from phenols was studied. Copper chloride catalysis favored PCDF formation, with lower chlorinated phenols significantly influencing product distribution.
Area of Science:
- Environmental Chemistry
- Organic Chemistry
- Chemical Engineering
Background:
- Polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF) are persistent organic pollutants.
- Phenols are recognized as key precursors in the formation of PCDD/F.
- Municipal waste incinerator (MWI) exhaust gases contain a distribution of phenolic compounds.
Purpose of the Study:
- To investigate the homologue and isomer patterns of PCDD/F formed from a mixture of 20 phenols under specific catalytic conditions.
- To understand the influence of phenol precursors on PCDD/F formation.
- To establish characteristic fingerprints for PCDD/F attribution in CuCl2-catalyzed reactions.
Main Methods:
- Utilized an isothermal flow reactor operating at 400°C.
- Employed a synthesized mixture of 20 phenols, representative of MWI exhaust, as reactants.
- Used a carrier gas mixture of 92% nitrogen (N2) and 8% oxygen (O2).
Main Results:
- Formation of dibenzofuran (DF) and PCDF was favored over dibenzo-p-dioxin (DD) and PCDD.
- The major homologue groups were non-chlorinated DD and DF; PCDD/F fraction decreased with increasing chlorination.
- PCDD/F homologue and isomer distributions remained relatively constant, with phenol and lower chlorinated phenols playing a significant role.
Conclusions:
- CuCl2-catalyzed reaction of phenols yields specific PCDD/F homologue and isomer patterns.
- The distribution of phenolic precursors, particularly less chlorinated ones, dictates the resulting PCDD/F congener profiles.
- The findings provide valuable fingerprints for attributing PCDD/F formation sources in similar catalytic processes.