- Reactivity features of polychlorobiphenyl congeners in the nucleophilic substitution reactions
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Groups of congeners and individual congeners of polychlorobiphenyls contributing to the composition of the technical mixture "Sovol" (PCB 60, PCB 64, PCB 70, PCB 74, PCB 97, PCB 101, PCB 105, PCB 110, PCB 118, PCB 138, PCB 149, PCB 156, and PCB 163) were
- Gorbunova,Pervova,Saloutin,Chupakhin
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experimental part
p. 138 - 143
(2012/06/04)
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- Synthesis of polychlorinated biphenyls and their metabolites with a modified Suzuki-coupling
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A modified procedure for the synthesis of polychlorinated biphenyls (PCBs) utilizing the Suzuki-coupling, a palladium-catalyzed cross-coupling reaction, is described. The coupling of (chlorinated) benzene boronic acids with bromochlorobenzenes, using Pd(dppf)2Cl2 (dppf=1,1 ′-bis(diphenylphosphino)ferrocene) as the catalyst and aqueous sodium carbonate as the base, gave the desired PCB congeners in moderate to good yields. Eleven PCB congeners, including environmentally important PCB congeners and metabolites, were synthesized using this modified procedure. This new catalyst Pd(dppf)2Cl2 offers the advantage of being less air-sensitive and has a longer shelf life compared to Pd(PPh4) 4. Three new (di-)methoxylated PCB congeners were synthesized using the same procedure by either coupling a chlorinated benzene boronic acid with a bromo (di-)methoxybenzene or by coupling a (di-)methoxy benzene boronic acid with a chlorinated bromobenzene. The dimethoxylated PCB congeners were readily converted into the respective dihydroxylated PCB derivatives using boron tribromide in dichloromethane. This approach offers the advantage of high selectivity and moderate to good yields compared to conventional methods such as the Cadogan reaction and allows the use of less toxic starting materials.
- Kania-Korwel, Izabela,Parkin, Sean,Robertson, Larry W.,Lehmler, Hans-Joachim
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p. 735 - 744
(2007/10/03)
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- Physical, spectral and chromatographic properties of all 209 individual PCB congeners
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Through the use of two capillary GC columns: 40% octadecyl/ 15% phenyl methyl siloxane and 50% phenyl methyl siloxane, it was possible to separate 201 PCB congeners with only four unresolved pairs. The data compiled in this study for all 209 congeners will aid in the identification of selected individual components of these environmental pollutants. The use of this data also presents the opportunity for the improved quantification of the commercial PCB formulations. -from Authors
- Bolgar,et al.
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p. 2687 - 2705
(2007/10/03)
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