189-64-0Relevant articles and documents
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.
Lee, Robert G. M.,Coleman, Peter,Jones, Joanne L.,Jones, Kevin C.,Lohmann, Rainer
, p. 1436 - 1447 (2007/10/03)
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.
Synthesis of dibenzopyrenes and pyrenes via photolytic sulfur extrusion and intramolecular cross-coupling reactions of dithia[3.3] (1,3)naphthalenophanes and dithia[3.3]metacyclophanes
Ashram,Miller,Bridson,Georghiou
, p. 6476 - 6484 (2007/10/03)
The syntheses of several substituted dithia[3.3]metacyclophanes and dithia[3.3](1,3)naphthalenophanes are reported and their photolyses in triethyl or trimethyl phosphite are described. Under these conditions, the corresponding tetrahydrodibenzopyrenes and tetrahydropyrenes are produced in a one-pot procedure when the precursor dithianaphthalenophanes and dithiacyclophanes possess at least one intraannular methoxyl group. A mechanism with supporting evidence is proposed to account for these results. Structural determinations of the four isomeric 11,22-dimethoxy-2,13- dithia[3.3](1,3)naphthalenophanes by NMR and X-ray single-crystal diffraction studies are also described. The syntheses of the novel anti-transoid- and anti-cisoid-[2.2](1,3)naphthalenophanes are also described.
Toward the Understanding of Benzannelated Annulenes: Synthesis and Properties of an - and -Ring Dibenzannelated Dihydropyrenes
Mitchell, Reginald H.,Williams, Richard Vaughan,Dingle, Thomas W.
, p. 2560 - 2571 (2007/10/02)
The dibenzannelated - and dihydropyrenes 5 and 7 and dimethyldihydropyrenes 4 and 6 were synthesized from 1,3-bis- and pyrene.The dimethyldihydropyrenes 4 and 6 are relatively stable and their diatropicities are discussed in relation to each other and to other benzannulenes in terms of Kekule structures and bond order calculations.It is shown that transoid fusion of the benzene rings on the annulene only somewhat perturbs the diatropicity of the annulene, whereas cisoid fusion strongly localizes the annulene macroring.Annulenes such as 6 which have transoid-fused benzenoid rings are also shown to display radicaloid properties.
