- Synthesis of chlorinated biphenyls by Suzuki cross-coupling using diamine or diimine-palladium complexes
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Several novel diimines (Salen-type ligands) 2a-2i and their reduced diamine counterparts 3b,3d-3g and 3i form complexes 4a-4i, 5b,5d-5g, and 5i with PdCl2 in DMF or methanol. Using 1 mol-% of the isolated complexes 4e and 5f many polychlorinated biphenyls (PCBs) can be prepared in moderate to excellent yields according to the Suzuki cross-coupling protocol with contact to air. Several 4-acetylbiphenyls prepared by this method can be converted in moderate yields into the corresponding biphenylcarboxylic acids (BCAs) by alkaline cleavage. An X-ray crystal structure determination confirms the structure of complex 5f. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Kylmaelae, Tuula,Kuuloja, Noora,Xu, Youjun,Rissanen, Kari,Franzen, Robert
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experimental part
p. 4019 - 4024
(2009/04/11)
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- Emission factors and importance of PCDD/Fs, PCBs, PCNs, PAHs and PM 10 from the domestic burning of coal and wood in the U.K.
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This paper presents emission factors (EFs) derived for a range of persistent organic pollutants (POPs) when coal and wood were subject to controlled burning experiments, designed to simulate domestic burning for space heating. A wide range of POPs were emitted, with emissions from coal being higher than those from wood. Highest EFs were obtained for particulate matter, PM10, (~ 10 g/kg fuel) and polycyclic aromatic hydrocarbons (~ 100 mg/ kg fuel for ΣPAHs). For chlorinated compounds, EFs were highest for polychlorinated biphenyls (PCBs), with polychlorinated naphthalenes (PCNs), dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) being less abundant. EFs were on the order of 1000 ng/kg fuel for ΣPCBs, 100s ng/ kg fuel for ΣPCNs and 100 ng/kg fuel for ΣPCDD/Fs. The study confirmed that mono- to trichlorinated dibenzofurans, Cl1,2,3DFs, were strong indicators of low temperature combustion processes, such as the domestic burning of coal and wood. It is concluded that numerous PCB and PCN congeners are routinely formed during the combustion of solid fuels. However, their combined emissions from the domestic burning of coal and wood would contribute only a few percent to annual U.K. emission estimates. Emissions of PAHs and PM 10 were major contributors to U.K. national emission inventories. Major emissions were found from the domestic burning for Cl1,2,3DFs, while the contribution of PCDD/F-ΣTEQ to total U.K. emissions was minor.
- Lee, Robert G. M.,Coleman, Peter,Jones, Joanne L.,Jones, Kevin C.,Lohmann, Rainer
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p. 1436 - 1447
(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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