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Organic matter from some hydrothermal deposits of Eastern Siberia
Published in Adam Piestrzyński, Mineral Deposits at the Beginning of the 21st Century, 2001
D.Kh. Martikhaeva, A.G. Polozov
Analysis of the hexane fraction by GC-MS has established specific features of individual bitumen samples. In a review (Martikhaeva 2000), it was concluded that the PAHs of hydrothermal associations contained naphthalene + phenanthrene, and pyrene + chrysene + coronene in all bitumen fractions. Thus, the compounds of the first association (naphthalene + phenanthrene) are found in all bitumens, except for sample 2. The second association (pyrene + chrysene + coronene) also was identified in all bitumens, except for sample 7. The association characteristic of oil asphaltenes (chrysene + benzpyrene) is found only in the brecciated and hydrothermally altered dolomites of sedimentary strata in the Sugunakh tectonic block (samples 1 and 2), reflecting features of sedimentary bitumens. As for the bitumen from the Yubileinoe iron-ore deposit (sample 5), that fact indicates the involvement of the organic matter from sedimentary strata into the ore-forming fluids. In the Kuryltyken deposits and hydrothermally altered dolomites of the Sugunakh tectonic block (samples 4 and 2), 1,12-benzperylene and perylene (respectively) were found. From the review data available, these compounds characterize the PAHs of recent sediments. The bitumen from sample 2 is characterized also by benzfluoranthene, a PAH associated with volcanics. Further PAH studies using published data will update compositional variations in PAHs in various geologic settings.
Introduction
Published in R. A. Jenkins, M. R. Guerin, B. A. Tomkins, The Chemistry of Environmental Tobacco Smoke, 2000
R. A. Jenkins, M. R. Guerin, B. A. Tomkins
PAHs ranging in size from naphthalene (2 rings) to coronene (6 rings) have been detected in indoor air. The most commonly reported PAHs are naphthalene and its methyl substituted derivatives; anthracene and phenanthrene; fluoranthene; pyrene, chrysene, and benz[a]anthracene; benzofluoranthenes; benzo[a]pyrene and benzo[e]pyrene; dibenz[a,h]anthracene; benzo[ghi]perylene; indeno[l,2,3-cd]pyrene; and coronene. It is not clear whether these chemicals are so frequently reported because they are the only or the predominant PAHs present, or because they are the most confidently detected by commonly employed analytical methods. One would expect that perylene and alkyl-substituted derivatives of many of the above parent compounds would also be frequently present, but they are much less often reported.
Inhalable Particulate Matter and Extractable Organic Matter Receptor Source Apportionment Models for the ATEOS Urban Sites
Published in Paul J. Lioy, Joan M. Daisey, Toxic Air Pollution, 1987
Maria T. Morandi, Joan M. Daisey, Paul J. Lioy
Factor 4, which accounted for 6.3% of the variance in the data, was strongly correlated with Pb (0.739) and COmax (0.702%), explaining 54% and 49% of their respective communalities. It was also weakly associated with Cd, Cu, and Ni. These results suggest that Factor 4 was related to motor vehicle emissions. Lead was not an appropriate tracer for this source in Newark because, as the FA results indicate, it was also associated with other source types. Stocks (1960) and Sawicki (1963) have indicated that benzo(ghi)perylene (BghiP), benzo(a)pyrene (BaP), and coronene (COR) are enriched in motor vehicle exhaust. When these three PAHs were included separately in the FA procedure, they loaded highly on Factor 4 (0.71, 0.62, and 0.53 correlations, respectively). However, their use as tracers is questionable because they are also emitted by other combustion sources, are subject to evaporative and/or reaction losses during sampling (Commins, 1962), and have a relatively short atmospheric half-life under photochemical smog conditions (Daisey, 1980). Alternatively, CO is a long-lived gas strongly associated with motor vehicle emissions, which are its main source in urban areas. Therefore, COmax could be a suitable tracer for these emissions in Newark (Morandi et al., 1983). Since there were no clearly unique tracers for motor vehicles in Newark, all the previously discussed variables were considered during development of the apportionment model.
Two-dimensional coronene fractal structures: topological entropy measures, energetics, NMR and ESR spectroscopic patterns and existence of isentropic structures
Published in Molecular Physics, 2022
Micheal Arockiaraj, Joseph Jency, Jessie Abraham, S. Ruth Julie Kavitha, Krishnan Balasubramanian
Benzenoid hydrocarbons are polycyclic, fully conjugated, unsaturated compounds comprised of six-membered rings with intriguing characteristics that continue to attract chemists to investigate their physico-chemical properties with respect to aromaticity and molecular structure. It is observed that the graphene segments [1] made up of these benzenoid compounds exhibit large π-conjugated systems with strong intermolecular interactions and high-order columnar packing [2,3], providing a suitable material for building organic semiconductors [4,5] and opto-electronic devices [6,7]. The skeletons of these benzenoid hydrocarbon molecules are represented as benzenoid systems. They possess a connected molecular graph structure similar to a honeycomb lattice without cut vertices and non-hexagonal interior faces [8]. Coronene is one such highly symmetrical, planar benzenoid compound consisting of seven aromatic, peri-fused benzene rings [9–11]. Though it was synthesised way back in 1940, it remains as one of the remarkable molecules in organic chemistry [12–14]. Its unique electronic structure, owing to the delocalisation of aromaticity among the outer six rings, and its six-fold structural symmetry assists in the formation of thin films and crystallisation of molecules [15] and enables enhanced electron mobility and better self-assembly to form stacks and ribbons inside nanotubes [16–18], resulting in nanomaterials with potential optical and electronic properties [19–22].