Polynuclear aromatic hydrocarbons. Naphthalene

Polynuclear aromatic hydrocarbons (naphthalene, phenanthrene, pyrene), thiourea... 

Also, the PET between polynuclear aromatic hydrocarbons (naphthalene, anthracene, phenanthrene, perylene) or heteroaromatics (phenazine, acridine) as acceptors and amines as donors can be used for polymerization initiation of AN and alkyl methacrylates [111-113]. In general, a reaction course as outlined in Scheme 3 also acts with these combinations. 

The purpose of this eornpuLer project is Lo examine several polynuclear aromatic hydrocarbons and to relate their electron density patterns to their carcinogenic activity. If nucleophilic binding to DN.A is a significant step in blocking the normal transcription process of DN.A, electron density in the hydrocarbon should be positively correlated to its carcinogenic potency. To begin with, we shall rely on clinical evidence that benzene, naphthalene, and phenanthrene... 

In the presence of certain ethers such as Me20, Me0CH2CH20Me or tetrahydrofuran, Na forms deep-green highly reactive paramagnetic adducts with polynuclear aromatic hydrocarbons such as naphthalene, phenanthrene, anthracene, etc. ... 

Varanasi, U. and D.J. Gmur. 1981. In vivo metabolism of naphthalene and benzo[a]pyrene by flatfish. Pages 367-376 in M. Cooke and A.J. Dennis (eds.). Chemical Analysis and Biological Fate Polynuclear Aromatic Hydrocarbons. Fifth International Symposium. Battelle Press, Columbus, OH. 

There are indications that pure naphthalene (a constituent of mothballs, which are, by definition, toxic to moths) and alkylnaphthalenes are from three to 10 times more toxic to test animals than are benzene and alkylbenzenes. In addition, and because of the low water solubility of tricyclic and polycyclic (polynuclear) aromatic hydrocarbons (i.e., those aromatic hydrocarbons heavier than naphthalene), these compounds are generally present at very low concentrations in the water-soluble fraction of oil. Therefore, the results of this smdy and others conclude that the soluble aromatics of crude oil (such as benzene, toluene, ethylbenzene, xylenes, and naphthalenes) produce the majority of its toxic effects in the enviromnent. 

To determine the concentrations of benzene, toluene, ethylbenzene, and xylenes, approved methods (e.g., EPA SW-846 8021B, SW-846 8260) are not only recommended but are insisted upon for regulatory issues. Polynuclear aromatic hydrocarbons (PAHs) may be present in condensate, and evaluation of condensate contamination should include the use of other test methods (EPA SW-846 8270, SW-846 8310) provided that the detection limits are adequate to the task of soil and groundwater protection. Generally, at least one analysis may be required for the most contaminated sample location from each source area. Condensate releases in nonsensitive areas require analysis for naphthalene only. The analysts should ensure that the method has detection limits that are appropriate for risk determinations. 

In a similar manner, expression of biodegradable hydrocarbons as a ratio to high-molecular-weight polynuclear aromatic hydrocarbons should have potential for fingerprinting purposes. The failure of some attempts to use PAHs for this purpose arises from the poor choice of molecules for comparison. Low-molecular-weight PAHs such as naphthalene or phenanthrene are often selected because of their abundance and relative ease of measurement, but these molecules are also the most prone to biodegradation as well as other forms of attenuation (Sadler and Connell, 2002). 

At the Sikes Disposal Pits Superfund site in Crosby, Texas, an HTTS unit was used to treat hazardous organic compounds including phenolic compounds, xylene, benzene, polynuclear aromatic hydrocarbons (PAHs), toluene, creosote, dichloroethane (DCA), vinyl chloride, and naphthalene (D184581, p. 216). The estimated treatment cost was 115 million including approximately 20 million in capital costs and 95 million in operation and maintenance costs. The estimated total cost for thermal treatment was 81 million. A total of 496,000 tons of soil and debris were incinerated. This corresponds to a total unit cost for incineration of 230 per ton and a unit cost of 160 per ton for thermal treatment (D184581, p. 227). 

Conditions for the mononitration of naphthalene, typical of the more reactive polynuclear aromatic hydrocarbons, are to be found in Expt 6.17. Naphthalene can also be nitrated by a mixture of nitric acid and glacial acetic acid, a reagent also suitable for some polyalkylated benzenes. 

Many polynuclear aromatic hydrocarbons form 1 1 molecular compounds (71-complexes) with picric acid, for example, naphthalene picrate C10H8 C6H2(NO2)3OH. Some picrates, e.g. anthracene picrate, are so unstable as to be decomposed by many, particularly hydroxylic, solvents they therefore cannot be easily recrystallised but may be washed with a little ether and dried on a porous title. Their preparation may often be accomplished in such non-hydroxylic solvents as chloroform, benzene or ether. The picrates of hydrocarbons can be readily separated into their constituents by warming with dilute ammonia solution and filtering (if the hydrocarbon is a solid) through a moist filter paper. The filtrate contains the picric acid as the ammonium salt, and the hydrocarbon is left on the filter paper. 

Quality (DEQ) found that the use of TDF as a supplemental fuel at Ash Grove did not enhance the potential for dioxin formation.20 The same report described screening tests performed for 17 specific polynuclear aromatic hydrocarbons (PAH s). Only three PAH s were detected (naphthalene, dibenzofuran, and phenanthrene) and each were detected in all eight samples. However, the highest levels of these compounds were detected while firing normal fuel (gas and coal), not when burning TDF.20... 

Aromatic compounds with two or more fused aromatic rings. Naphthalene is a polynuclear aromatic hydrocarbon (PAH or PNA). Indole is a polynuclear aromatic heterocycle, (p. 735)... 

Based on the screening analysis and methodology described, nickel, vanadium, methanol, carbon tetrachloride, xylenes, toluene, ethylene, propylene, naphthalene, ethylbenzene, polynuclear aromatic hydrocarbons (RAHs), 1,2,4-trimethylbenzene, and cyclohexane were not evaluated further, since their exposure either posed less than a one-in-a-million excess risk or was below the applicable reference dose. 

Multiple ring aromatic compounds are commonly referred to as polynuclear aromatic hydrocarbons or PAHs. The most common PAH is naphthalene. Naphthalene is a two-ringed unit. Three, four or more fused ring compounds also exist. 

Identification of the Fluorescent Species. Figure 2 compares the fluorescence excitation spectra of the polymers with the absorption spectrum of a simple ,/3-unsaturated carbonyl compound (pent-3-ene-2-one) (13). The three spectra are very similar. Figure 2 shows also that the fluorescence from the polymers in the region 300-400 nm cannot be caused by the presence of polynuclear aromatic hydrocarbons such as naphthalene as postulated earlier by Carlsson and Wiles (13). Furthermore, as shown below, the excitation spectrum also differs significantly from that of a fully saturated aldehyde or ketone. 

Schmeltz, 1., J. Tosk, J. Hilfrich, N. Hirota, and D. Hoffmaim Bioassays of naphthalene and alkylnaphtha-lenes for cocarcinogenic activity. Relation to tobacco carcinogenesis in Polynuclear aromatic hydrocarbons. Vol. 3, edited by P.W. Jones and R.L Freudenthal, Raven Press, New York, NY (1978) 47-60. 

Polynuclear aromatic hydrocarbons are the most easily oxidized on catalyst surfaces. Perylene and anthracene have been the most commonly used hydrocarbons, and their cation radicals have been characterized in such work by esr and absorption spectroscopy. Naphthalene (Rooney and Pink, 1962) and naphthacene (Flockhart et al., 1966) have been used, but their oxidation to the cation radical goes only poorly. 

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