Download or read book Experimental and Theoretical Studies of Nitrated Polycyclic Aromatic Hydrocarbons written by Kefa Karimu Onchoke and published by . This book was released on 2006 with total page 382 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Experimental and theoretical methods were used to study the structure, and spectroscopic properties of carcinogenic nitrated polycyclic aromatic hydrocarbons Structure-function and structure-spectroscopy correlations were examined. Initial investigations focused on the relationships between the orientation of the nitro group relative to the plane of the aromatic ring, vis-a-vis known mutagenic effects. Synthesis of specific isomers of nitro-PAHs and elucidation of their crystal structure is required to establish the validity of the structure-function relationships. Such studies are scarce. Fortunately, electronic structure calculations can be readily done. We used density functional theory calculations to predict structures of 1-, 2-nitronaphthalenes, 1-, 2-, 9-nitroanthracenes, 1-, 2-, 3-, 4-, 9-nitrophenanthrenes, 1-, 2-, 4-nitropyrenes, 6-nitrochrysene, 1-, 3- and 6-nitrobenzo[a]pyrenes. In accord with other studies, we showed that the mutagenic ability of one nitro-PAH isomer over another in the same ring may be predicted from its dihedral angle. However, 1-, 2- and 4-nitropyrene with calculated C-C-N-O angles of ~23°, 0° and 26°, respectively, presented contradictory results. We suggest that the nitrated pyrenes undergo different enzymatic reduction routes when interlocking to enzymes. For further insights into structure-function and structure-spectroscopy correlations, 1-, 3-, and 6-nitrobenzo[a]pyrene were synthesized. Detailed infrared and Raman spectroscopic data of BaP, and its three mononitrated isomers are provided for the first time. By utilizing B3LYP/6-311+G**, the molecular geometries and the vibrational spectra was calculated. Good agreement between calculated and experimental geometry for BaP was noted, and predictions of the vibrational data for all compounds were within ~5 cm−1 of the experimental data. [nu]sNO2/[nu]asNO2 assignments are proposed. The geometrical distortions of the BaP structure upon nitro group substitution and correlations between structural parameters and vibrational data, and structure-function relationships related to the mutagenicity are discussed. The profound influence and electronic effects of the nitro group was shown to correlate to quantum yield ([phi]f) trends. Nitro-PAHs whose nitro group was non-planar to the aromatic plane exhibited higher quantum yields, and showed absorption bands similar to the parent PAH. UV-Vis absorption bands of the singlet excitation states were assigned via TDDFT, and the [pi]PAH ring [right arrow] [pi]PAH ring excitations mainly predominated in nitro-PAHs with a non-planar nitro group.
Download or read book Nitrated Polycyclic Aromatic Hydrocarbons written by Lisa C. Bosch and published by . This book was released on 1985 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental and Theoretical Studies on the Excited Electronic States of Some Aromatic Hydrocarbons Through Electric Field Perturbation and Through Chemical Substituents written by Richard Alfred Mathies and published by . This book was released on 1974 with total page 482 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Toxicological Profile for Polycyclic Aromatic Hydrocarbons written by and published by . This book was released on 1995 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Analysis of Nitrated Polycyclic Aromatic Hydrocarbons PAH quinones and Related Compounds in Ambient Air written by Arthur Greenberg and published by . This book was released on 1986 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Polycyclic Aromatic Hydrocarbons written by and published by National Academies Press. This book was released on 1983-01-01 with total page 482 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Formation of Nitrated Polycyclic Aromatic Hydrocarbons in Diesel Particulate Filters written by Matteo Carrara and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Atmospheric Chemistry of Particulate bound Polycyclic Aromatic Hydrocarbons written by Narumol Jariyasopit and published by . This book was released on 2013 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: The trans-Pacific atmospheric transport of particulate matter (PM)-bound polycyclic aromatic hydrocarbons (PAHs) to remote sites in western North America has been well documented and has triggered research questions regarding to atmospheric transformation of PM-bound PAHs and the potential impacts on human health from their inhalation exposure. In this dissertation, field measurements, theoretical studies, laboratory experiments, and mutagenicity studies were used to begin the address the questions as to whether PM-bound PAHs undergo atmospheric transformation into mutagenic nitro-PAHs (NPAHs) during trans-Pacific atmospheric transport. PM extracts were tested in the Salmonella mutagenicity assay, using Salmonella typhimurium strain TA98 (with and without metabolic activation), to determine the mutagenic activities in relation to the chemical composition of the extracts. The sampling of atmospheric PM with diameter
Download or read book Oxidation and Reduction Process for Polycyclic Aromatic Hydrocarbons and Nitrated Polycyclic Aromatic Hydrocarbons written by Zhenjiao Tian and published by . This book was released on 2008 with total page 143 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Epoxidation is the first metabolic activation step necessary for polycyclic aromatic hydrocarbons (PAHs) to exert their biological activity. Nitrated polycyclic aromatic hydrocarbons (NPAHs) may undergo nitro reduction or ring oxidation, or a combination of ring oxidation and nitro reduction. We used density functional theory at the B3LYP/6-31+G**//B3LYP/6-31G* level of theory to explore both the reduction of NPAHs and epoxidation of PAHs and NPAHs. Substituent effects on the stability of nitrobenzene and its derivatives generated in the process of the nitro reduction were investigated. Two linear (free) energy relationships were observed: (1) a correlation between the enthalpy difference [delta]H0meta [[delta]H0 = H0 (meta) - H0 (para)] and the charge differences on the carbon bonded to the reaction site for neutral molecules; and (2) a correlation between the [delta]H0meta and the Hammett substituent constant difference [delta][sigma] ([delta][sigma] = [sigma]m - [sigma][rho]). We also explored substituent and solvent effects on the reduction, and linear Hammett correlations were obtained. The effects of ring systems on the reduction thermodynamics were also examined. Larger ring systems and azaheterocycles were found to be generally more feasibly reduced than the parent nitrobenzene system. The thermochemistry of the epoxidation reactions of various PAHs and NPAHs were explored. The regioselectivities of the epoxidations were found to be consistent with the available experimental data. We also investigated the isomerization process for arene oxides, derived from both PAHs and NPAHs, to form the corresponding oxepines. The calculated results quantitatively demonstrate the facility and the feasibility of the isomerization at room temperature. The results reveal the significant effect of the aromaticity changes on the isomerization. By comparing the results for NPAHs with the results for PAHs, the effect of the nitro group on the isomerization was found to be dependent on the location of the oxirane and the structure of the NPAH. The calculations also reveal that solvation effects on the isomerization of the NPAH oxides are different from and more complex than that of the parent PAH oxides. Our results elucidate the origin of the racemization of the optically active arene oxides.
Download or read book Polynuclear Aromatic Compounds written by Lawrence B. Ebert and published by . This book was released on 1988 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presents accounts of current research in polynuclear aromatic compounds, showing examples of studies both of pure compounds and of complex, fossil fuel related mixtures. Offers a thorough knowledge of aromatic chemistry through coverage of reduction, oxidation, and thermal reactions--including applications developed for both coal and petroleum materials. Featured topics include quantum chemical structure-reactivity relationships, spatial configurations of large polynuclear hydrocarbons, cyclophanes, and desulfurization of heterocycles. Scientists studying all aspects of the chemistry of polynuclear aromatics will discover important, pertinent information in this volume.
Download or read book Nitrated Polycyclic Aromatic Hydrocarbons in Food written by Kailin Deng and published by . This book was released on 2018 with total page 167 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Chemistry of the Upper and Lower Atmosphere written by Barbara J. Finlayson-Pitts and published by Elsevier. This book was released on 1999-11-17 with total page 993 pages. Available in PDF, EPUB and Kindle. Book excerpt: Here is the most comprehensive and up-to-date treatment of one of the hottest areas of chemical research. The treatment of fundamental kinetics and photochemistry will be highly useful to chemistry students and their instructors at the graduate level, as well as postdoctoral fellows entering this new, exciting, and well-funded field with a Ph.D. in a related discipline (e.g., analytical, organic, or physical chemistry, chemical physics, etc.). Chemistry of the Upper and Lower Atmosphere provides postgraduate researchers and teachers with a uniquely detailed, comprehensive, and authoritative resource. The text bridges the "gap" between the fundamental chemistry of the earth's atmosphere and "real world" examples of its application to the development of sound scientific risk assessments and associated risk management control strategies for both tropospheric and stratospheric pollutants. - Serves as a graduate textbook and "must have" reference for all atmospheric scientists - Provides more than 5000 references to the literature through the end of 1998 - Presents tables of new actinic flux data for the troposphere and stratospher (0-40km) - Summarizes kinetic and photochemical date for the troposphere and stratosphere - Features problems at the end of most chapters to enhance the book's use in teaching - Includes applications of the OZIPR box model with comprehensive chemistry for student use
Download or read book The Aromatic Sextet written by Erich Clar and published by John Wiley & Sons. This book was released on 1972 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 728 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nitrated Polycyclic Aromatic Hydrocarbons Chromatographic Methods written by CM White (Ed) and published by . This book was released on 1985 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bitumens and Bitumen Emissions and Some N and S heterocyclic Polycyclic Aromatic Hydrocarbons written by IARC Working Group on the Evaluation of Carcinogenic Risks to Humans and published by World Health Organization. This book was released on 2013 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume of the IARC Monographs provides evaluations of the carcinogenicity of bitumens and their emissions, the N-heterocyclic polycyclic aromatic hydrocarbons benz[a]acridine, benz[c]acridine, dibenz[a,h]acridine, dibenz[a,j]acridine, dibenz[c,h]acridine, carbazole and 7H-dibenzo[c,g]carbazole, as well as the S-hetrocyclic polycyclic aromatic hydrocarbons benzo[b]naphtho[2,1-d]thiophene and dibenzothiophene. Bitumens are produced by distillation of crude oil during petroleum refining, and also occur naturally. Bitumens can be divided into six broad classes, according to their physical properties and specifications required for different applications. The major use (about 80%) of bitumens is for road paving; other uses include roofing, waterproofing, sealing and painting. The term "bitumen" should not be confused with "asphalt", which refers to the mixture of bitumen (4-10% by weight), small stones, sand and filler used for road paving. Bitumens are complex mixtures that contain a large number of organic chemical compounds. Application of bitumens may generate emissions (fumes and vapours) that may contain, among volatile and non-volatile compounds, a number of known or probable carcinogens. An IARC Monographs Working Group reviewed epidemiological evidence, animal bioassays, and mechanistic and other relevant data to reach conclusions as to the carcinogenic hazard to humans of various occupations that entail exposure to bitumens and bitumen emissions, including road paving, roofing, and application of mastic asphalt, and to various heterocyclic polycyclic aromatic compounds.
Download or read book Soot in Combustion Systems and Its Toxic Properties written by J. Lahaye and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 429 pages. Available in PDF, EPUB and Kindle. Book excerpt: Our interest in Mulhouse for carbon black and soot began some 30 years ago when J.B. Donnet developed the concept of surface chemistry of carbon and its involvement in interactions with gas, liquid and solid phases. In the late sixties, we began to study soot formation in pyrolytic systems and later on in flames. The idea of organ1z1ng a meeting on soot formation originated some four or five years ago, through discussions among Professor J.B. Howard, Dr. A. D'Alessio and ourselves. At that time the scientific community was becoming aware of the necessity to strictly control soot formation and emission. Being involved in the study of surface properties of carbon black as well as of formation of soot, we realized that the combustion community was not always fully aware of the progress made by the physical-chemists on carbon black. Reciprocally, the carbon specialists were often ignoring the research carried out on soot in flames. One objective of this workshop was to stimulate discussions between these two scientific communities. During the preparation of the meeting, and especially during the review process by the Material Science Committee of the Scientific Affairs Division of N.A.T.O. the toxicological aspect emerged as being an important component to be addressed during the workshop. To reflect these preoccupations we invited biologists, physical chemists and engineers, all leaders in their field. The final programme is a compromise of the different aspects of the subject and was divided in five sessions.
