Methylated polycyclic aromatic

Analytical Properties Separation of three- and four-member methylated polycyclic aromatic hydrocarbons (PAHs) on basis of length-to-breadth ratio (l/b) as l/b increases, retention time decreases cross-linking increases retention times, separation of methylcrypene isomers Reference 18... 

Braga, R.S., Barone, P.M.V.B. and Galvao, D.S. (1999) Identifying carcinogenic activity of methylated polycyclic aromatic hydrocarbons (PAHs). /. Mol. Struct. (Theochem), 464, 257—266. 

Identifying Carcinogenic Activity of Methylated Polycyclic Aromatic Hydrocarbons (PAHs). 

Des., 1, 115-133 (2002). QSAR Carcinogenic Study of Methylated Polycyclic Aromatic Hydrocarbons Based on Topological Descriptors Derived from Distance Matrices and Correlation Weights of Local Graph Invariants. 

Aromatic solvents or polycyclic aromatic hydrocarbons (PAFI) in water, e.g. can be detected by QCM coated with bulk-imprinted polymer layers. Flere, the interaction sites are not confined to the surface of the sensitive material but are distributed within the entire bulk leading to very appreciable sensor responses. Additionally, these materials show high selectivity aromatic solvents e.g. can be distinguished both by the number of methyl groups on the ring (toluene vs. xylene, etc.) and by their respective position. Selectivity factors in this case reach values of up to 100. 

On the basis of the reaction of alkyl radicals with a number of polycyclic aromatics, Szwarc and Binks calculated the relative selectivities of several radicals methyl, 1 (by definition) ethyl, 1.0 n-propyl, 1.0 trichloromethyl, 1.8. The relative reactivities of the three alkyl radicals toward aromatics therefore appears to be the same. On the other hand, quinoline (the only heterocyclic compound so far examined in reactions with alkyl radicals other than methyl) shows a steady increase in its reactivity toward methyl, ethyl, and n-propyl radicals. This would suggest that the nucleophilic character of the alkyl radicals increases in the order Me < Et < n-Pr, and that the selectivity of the radical as defined by Szwarc is not necessarily a measure of its polar character. 

The next eight chapters will be devoted to the ecotoxicology of groups of compounds that have caused concern on account of their real or perceived environmental effects and have been studied both in the laboratory and in the field. These are predominantly compounds produced by humans. However, a few of them, for example, methyl mercury, methyl arsenic, and polycyclic aromatic hydrocarbons (PAHs), are also naturally occurring. In this latter case, there can be difficulty in distinguishing between human and natural sources of harmful chemicals. 

Biopract provides technological products and processes for industry, agriculture, and environment. They not only produce technical enzyme preparations but also develop enzymes for applications in agriculture, food, and textile industry as well as in environmental technologies. On the later, bioremediation has been an area of service delivery from Biopract. Their activities regards microbial preparations for the bioremediation of organic contaminants (mineral oil (MKW), polycyclic aromatic hydrocarbons (PAH), benzene, toluene, ethylbenzene, xylene (BTEX), methyl-tert-butyl ether (MTBE), volatile organic hydrocarbons (VOC), and dimethyl sulfoxide (DMSO)). 

Methods for the synthesis of the biologically active dihydrodiol and diol epoxide metabolites of both carcinogenic and noncarcinogenic polycyclic aromatic hydrocarbons are reviewed. Four general synthetic routes to the trans-dihydrodiol precursors of the bay region anti and syn diol epoxide derivatives have been developed. Syntheses of the oxidized metabolites of the following hydrocarbons via these methods are described benzo(a)pyrene, benz(a)anthracene, benzo-(e)pyrene, dibenz(a,h)anthracene, triphenylene, phen-anthrene, anthracene, chrysene, benzo(c)phenanthrene, dibenzo(a,i)pyrene, dibenzo(a,h)pyrene, 7-methyl-benz(a)anthracene, 7,12-dimethylbenz(a)anthracene, 3-methylcholanthrene, 5-methylchrysene, fluoranthene, benzo(b)fluoranthene, benzo(j)fluoranthene, benzo(k)-fluoranthene, and dibenzo(a,e)fluoranthene. 

Effects of Methyl and Fluorine Substitution on the Metabolic Activation and Tumorigenicity of Polycyclic Aromatic Hydrocarbons... 

Human exposure to complex mixtures of polycyclic aromatic hydrocarbons (PAH) occurs through inhalation of tobacco smoke and polluted indoor or outdoor air, through ingestion of certain foods and polluted water, and by dermal contact with soots, tars, and oils CO. Methylated PAH are always components of these mixtures and in some cases, as in tobacco smoke and in emissions from certain fuel processes, their concentrations can be in the same range as some unsubstituted PAH. The estimated emission of methylated PAH from mobile sources in the U.S. in 1979 was approximately 1700 metric tons (2). The occurrence of methylated and unsubstituted PAH has been recently reviewed (1, 2). In addition to their environmental occurrence, methylated PAH are among the most important model compounds in experimental carcinogenesis. 7,12-Dimethylbenz[a]anthracene, one of... 

Fig. 5a-c. A typical distribution of polycyclic aromatic hydrocarbons in a atmospheric fallout sample, Alexandria City - Egypt b bottom incineration ash leachate of municipal solid waste - USA c hydrothermal petroleum, Escanaba Trough, NE Pacific Ocean. PAH Compound identifications N = naphthalene, MN = methylnaphthalene, DMN = dimethylnaphthalenes, P = phenanthrene, MP = methylphenanthrene, Fl = fluoranthene, Py = pyrene, BaAN = benzol anthracene, DH-Py = dihydropyrene, 2,3-BF = 2,3-benzofluorene, BFL = benzo[fc,/c]fluoranthene, BeP = benzo[e]pyrene, BaP = benzo[a]pyrene, Per = perylene, Cx-228 = methyl-228 series, Indeno = indeno[ l,2,3-c,d]pyrene, DBAN = dibenz[a,/z]anthracene, BPer = benzo[g,/z,z] perylene, AAN = anthanthrene, DBTH = dibenzothiophene, Cor = coronene, DBP = dibenzo [a,e]pyrene, DBPer = dibenzo [g,h,i] perylene... 

MPAH methyl-substituted polycyclic aromatic hydrocarbon... 

Wise, S.A., Sander, L.C., Lapouyade, R., and Garrigues, P., The anomalous behavior of selected methyl-substituted polycyclic aromatic hydrocarbons in reversed-phase liquid chromatography, J. Chromatogr., 514, 111, 1990. 

Such xenobiotics as aliphatic hydrocarbons and derivatives, chlorinated ahphatic compounds (methyl, ethyl, methylene, and ethylene chlorides), aromatic hydrocarbons and derivatives (benzene, toluene, phthalate, ethylbenzene, xylenes, and phenol), polycyclic aromatic hydrocarbons, halogenated aromatic compounds (chlorophenols, polychlorinated biphenyls, dioxins and relatives, DDT and relatives), AZO dyes, compounds with nitrogroups (explosive-contaminated waste and herbicides), and organophosphate wastes can be treated effectively by aerobic microorganisms. 

Arey, J., R. Atkinson, S. M. Aschmann, and D. Schuetzle, Experimental Investigation of the Atmospheric Chemistry of 2-Methyl-1-nitronaphthalene and a Comparison of Predicted Nitroarene Concentrations with Ambient Air Data, Polycyclic Aromat. Compd., 1, 33-50 (1990). 

Laali et al. have characterized carbocations generated from substituted polycyclic aromatic compounds. The related cation 157 is a true aryl-methyl-type ion, whereas cations 158 have arenium ion character because the strongly electron-withdrawing a-CF3 group enhances charge delocalization into the pyrenyl and phenyl groups. 

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