Polynuclear aromatic hydrocarbons and their derivatives

Pyrene, 11, is an inexpensive and readily available aromatic hydrocarbon that displays a relatively low order of toxicity. Pyrene was easily derivatized by the pathways shown in Diagram 2.3 to give three interesting PSs, 19-21 [CRI 02a]. 

1-Pyrenemethanol, 19, is readily soluble in various epoxide monomers and has the advantage that it undergoes acid catalyzed and radical reactions that covalently bind it into the pol5mier matrix as photopolymerization proceeds. Similar considerations apply to compound 20 which, in addition to the reactive benzylic hydroxyl group, has a long alkyl chain that markedly improves solubility in a variety of vinyl and heterocyclic monomers. Like the above anthracene compounds, pyrene and its derivatives 19-21 are active as PSs for diaryliodonium, triarylsulfonium and also dialkylphenacylsulfonium salts. 

As mentioned previously, the value determined by polarography for N-alkoxy pyridinium salts is of the order of-16 kcal/mol. This indicates that N-alkoxypyridinium salts would be expected to undergo facile reduction by photoexcited electron-rich compounds. Indeed, electron-transfer photosensitization by typical excited state electron donors such as anthracene, perylene, thioxanthene [YAG 93] and trimethoxybenzene [YAG 93] has been reported. 

Diagram 2.4 depicts the proposed mechanism of the electron-transfer photosensitization of a typical alkoxypyridinium photoinitiator, 25, by excited anthracene [YAG 94], As shown in equation [2.11], the alkoxypyridine radical, 26, undergoes forther irreversible decomposition to give pyridine and an alkoxy radical. 

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The fluorescence detector is a specific and concentration-sensitive detector. It is based on the emission of photons by electronically excited molecules. Fluorescence is especially observed for analytes with large conjugated ring systems, e.g., polynuclear aromatic hydrocarbons and their derivatives. In order to extend its applicability range, pre-column or post-column derivatization strategies have been developed [9]. 

Kohlenwasserstoffe und ihrer Abkommlinge. I. Dibenzanthracene und ihrer Chinone [Knowledge of polynuclear aromatic hydrocarbons and their derivatives. 774. 

Prycek, J., Ciganek, M., and Simek, Z., Development of an analytical method for polynuclear aromatic hydrocarbons and their derivatives. Journal of Chromatography A, 1030, 103, 2004. 

Residual fuel oil is generally more complex than distillate fuels in composition and impurities. Limited data are available, but there are indications that the composition of No. 6 fuel oil includes (volume basis) aromatics (25%), paraffins (15%), naphthenes (45%), and nonhydrocarbon compounds (15%). Polynuclear aromatic hydrocarbons and their alkyl derivatives and metals are important hazardous and persistent components of No. 6 fuel oil. 

Heidelberger, C. 1976. Studies on the mechanisms of carcinogenesis by polycyclic aromatic hydrocarbons and their derivatives. In R. Freudenthal and P.W. Jones (Eds.), Carcinogenesis—a comprehensive survey. Volume I. Polynuclear aromatic hydrocarbons chemistry, metabolism, and carcinogenesis. Raven Press, New York, pp. 1-8. 

For characterisation, aromatic hydrocarbons can be sulphonated, chloro-sulphonated, carboxybenzoylated and nitrated. Polynuclear aromatic hydrocarbons, and many of their derivatives, yield crystalline adducts with picric acid, styphnic acid, 1,3,5-trinitrobenzene and 2,4,7-trinitrofluorenone. 

Indisputably, the most significant contributions to polycyclic aromatic hydrocarbons originated with Clar at the beginning of this decade. His efforts were published in the journal series Polynuclear Aromatic Hydrocarbons and/or Aromatic Hydrocarbons [27] as well as in an excellent two volume series, Polycyclic Hydrocarbons, [la] which provided a comprehensive look at hydrocarbon diversity. Not only did he and his coworkers produce an exceeding number of new carbon-rich structures, but his adaptation and development of new synthetic methodologies allowed confirmation of structure as well as improved yields to provide sufficient quantities for physical property studies. Clar and coworkers continued their work well into the latter parts of the 20th century. His early work focused on benzo-, naphtho-, and anthraceno-derivatives of anthracene and phenanthrene [la]. 

An alternative starting point in chemically reacting fossil fuels is to treat them as if they were graphite. As noted earlier, graphite and larger polynuclear aromatic hydrocarbons are far from inert with respect to electron-transfer reactions, and thus the use of chemistry known to work for graphite may be of possible use in the investigation of coal, petroleum, and their derivatives. In the next two sections, we will discuss aspects of reduction and oxidation of carbonaceous solids and thereby parallel the chapters in this book on the reduction and oxidation of polynuclear aromatic hydrocarbon molecules. 

Moore MN, Pipe RK, Farrar SV (1982) Lysosomal and microsomal responses to environmental factors in Littorina littorea from Sullom Voe. Mar Pollut Bull 13 340-345 Moore MN, Mayernik JA, Giam CS (1985) Lysosomal responses to a polynuclear aromatic hydrocarbon in a marine snail effects of exposure to phenanthrene and recovery. Mar Env Res 17 230-233 Moore MN, Livingstone DR, Widdows J, Lowe DM, Pipe RK (1987) Molecular, cellular and physiological effects of oil-derived hydrocarbons on molluscs and their use in impact assessment. Phil Trans R Soc Lond B 316 603-623... 

Becker RS, Singh IS, Jackson EA. Comprehensive spectroscopic investigation of polynuclear aromatic hydrocarbons. I. absorption spectra and state assignments for the letracycUc hydrocarbons and their alkyl-substimied derivatives. J Chem Phys 1963 38 2144-71. 

Gawlik et al. [7] and Lyman et al. [15] provide an overview of Koc versus Kow equations and Sabljic compares estimation results derived with various ow-based models [14]. Sabljic discusses and compares these models with respect to the inaccuracy and incompatibility of the experimental Kow and Koc data [16]. Most of those models apply for polynuclear aromatics, halogenated hydrocarbons, or certain classes of pesticides. Abdul et al. [17] report excellent agreement between the versus K0Vi model derived with their experimental data and the model derived with a larger set of data. Paya-Perez et al. [18] have studied relationships for chlorobenzenes and PCBs. They found, however, that the corresponding correlation based on Sw as the independent variable is better than the one based on Kov/. Vowles and Mantoura... 

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