Nitration Pyrene

Headspace Effects and Stoichiometry. In the earlier accounts of pyrene nitration by N(IV), NO was a prominent reaction product, and each N204 ultimately yeilded IV3 nitropyrenes (7, 9). Our work found substantial effects of NO on reaction rate, as just discussed, and also effects of headspace on nitropyrene yields, as estimated spectrophotometrically. Specifically, we found in the runs with [Py] [N(IV)] that with a large headspace the 1-nitropyrene/N204 ratio ranged from 0.9 to 1.3 however, with a small head-space, this ratio approached and in some cases exceeded 2.0. 

Accordingly, a study of the stoichiometry of pyrene nitration by N(IV) in methylene chloride was conducted by using gas chromatography for analysis. The results are summarized as follows Starting with 79.1 (xmol of pyrene and 7.6 xmol of N(IV) led to a mass balance of 97.5% and a 1-nitropyrene/ N204 ratio of 2.4 starting with 109.8 xmol of pyrene and 15.1 (xmol of N(IV) led to a mass balance of 94.3% and a 1-nitropyrene/N204 ratio of 1.8. 

The aim of this work is the development of pyrene determination in gasoline and contaminated soils. For this purpose we used room temperature phosphorescence (RTP) in micellar solutions of sodium dodecylsulphate (SDS). For pyrene extraction from contaminated soils hexane was used. Then exttacts earned in glass and dried. After that remains was dissolved in SDS solution in the presence of sodium sulphite as deoxygenation agent and thallium (I) nitrate as heavy atom . For pyrene RTP excitation 337 nm wavelength was used. To check the accuracy of the procedures proposed for pyrene determining by RTP, the pyrene concentrations in the same gasoline samples were also measured by GC-MS. 

Imidazole derivatives 380 Imperatorin 65 Impregnation of TLC layers 86 -with caffeine 86 -with silver nitrate 86 -with tungstate 86 Indeno(l,2,3-cd)pyrene 39,85 Indicators, pH- 303 -, reagents 45 Indium cations 144 Indoleacetic acid 45... 

Considerable attention has been directed to the formation of nitroarenes that may be formed by several mechanisms (a) initial reaction with hydroxyl radicals followed by reactions with nitrate radicals or NO2 and (b) direct reaction with nitrate radicals. The first is important for arenes in the troposphere, whereas the second is a thermal reaction that occurs during combustion of arenes. The kinetics of formation of nitroarenes by gas-phase reaction with N2O5 has been examined for naphthalene (Pitts et al. 1985a) and methylnaphthalenes (Zielinska et al. 1989) biphenyl (Atkinson et al. 1987b,c) acephenanthrylene (Zielinska et al. 1988) and for adsorbed pyrene (Pitts et al. 1985b). Both... 

Fig. 5 Main contamination sources identified by PCA for sediments, fish, and suface water in the Ebro River basin, and explained variances for each principal component. Variable identification. Organic compounds in sediments 1, summatory of hexachlorocyclohexanes (HCHs) 2, summa-tory of DDTs (DDTs) 3, hexachlorobenzene (HCB) 4, hexachlorobutadiene (HCBu) 5, summatory of trichlorobenzenes (TCBs) 6, naphthalene 7, fluoranthene 8, benzo(a)pyrene 9, benzo(b) fluoranthene 10, benzo(g,h,i)perylene 11, benzo(k)fluoranthene 12, indene(l,2,3-cd)pyrene. Organic compounds in fish 1, hexachlorobenzene (HCB) 2, summatory of hexachlorocyclohexanes (HCHs) 3, o,p-DDD 4, o,p-DDE 5, o,p-DDT 6, p,p-DDD 7, />,/>DDE 8, />,/>DDT 9, summatory of DDTs (DDTs) 10, summatory of trichlorobenzenes (TCBs) 11, hexachlorobutadiene (HCBu) 12, fish length. Physico-chemical parameters in water 1, alkalinity 2, chlorides 3, cyanides 4, total coliforms 5, conductivity at 20°C 6, biological oxygen demand 7, chemical oxygen demand 8, fluorides 9, suspended matter 10, total ammonium 11, nitrates 12, dissolved oxygen 13, phosphates 14, sulfates 15, water temperature 16, air temperature...

In a solution containing oxygen, photolysis yields a mixture of 6,12-, 1,6-, and 3,6-diones. Nitration by nitrogen dioxide forms 6-nitro-, 1-nitro-, and 3-nitrobenzo[a]pyrene. When benzo [a] pyrene in methanol (1 g/L) was irradiated at 254 nm in a quartz flask for 1 h, the solution turned pale yellow. After 2 h, the solution turned yellow and back to clear after 4 h of irradiation. After 4 h, 99.67% of benzo[a]pyrene was converted to polar compounds. One of these compounds was identified as a methoxylated benzo[a]pyrene (Lu et al, 1977). A carbon dioxide yield of 26.5% was achieved when benzo [a] pyrene adsorbed on silica gel was irradiated with light (A, >290 nm) for 17 h (Freitag et al, 1985). 

When benzo[a]pyrene adsorbed from the vapor phase onto coal fly ash, silica, and alumina was exposed to nitrogen dioxide, no reaction occurred. However, in the presence of nitric acid, nitrated compounds were produced (Yokley et al, 1985). Chlorination of benzo [a] pyrene in polluted humus poor lake water gave ll,12-dichlorobenzo[a]pyrene and 1,11,12-, 3,11,12- or 3,6,11-... 

Peroxyacyl nitrates, see Acetaldehyde, Butane, 2-Bntanone, 2,3-Dimethylbntane Peroxybenzoic acid, see Toluene Peroxynitric acid, see Formaldehyde Peroxypropionyl nitrate, see 2-Methylpentane, Pentane Phenanthrene, see Anthracene, Bis(2-ethylhexyl) phthalate, Naphthalene Phenanthrene-9,10-dione, see Phenanthrene 9,10-Phenanthrenequinone, see Phenanthrene 4-Phenanthroic acid, see Pyrene... 

Cation-radicals of naphthalene and its homologues, pyrene, or perylene react with NOj" ion in AN, giving electron-transfer products, that is, ArH and NOj. The latter radical is not very active in these reactions and nitration takes place only with extremely reactive compounds such as perylene (Eberson and Radner 1985, 1986). This mechanism is seemingly distinctive of compounds with E° less or equal to 1 V in AN (or in other solvents solvating NOj ions sparingly). 

Maximum residue levels in certain foods are set for the following contaminants nitrate, my cotoxins (aflatoxins, ochratoxin A, pamlin, deoxynivalenol, zearalenone, fumonisins, T -2 and HT-2-toxin), metals (lead, cadmium, mercury, inorganic tin), 3-MCPD (3-monochloro-propane-l,2-diol), dioxins and PCBs, and polycyclic aromatic hydrocarbons (benzo(a)pyrene) (EC 2007c). 

Finally, while several volatile and semivolatile PAHs, e.g., naphthalene, the methylnaphthalenes, phenan-threne, pyrene, and fluoranthene, are not significant mutagens or carcinogens (hence not included in Table 10.13), they are precursors to powerful direct bacterial mutagens formed in gas-phase atmospheric reactions with hydroxyl during the day and nitrate radicals at night (see Section F). Furthermore, 2-nitrofluoranthene,... 

The generality of this reaction of N02 with particle-associated PAHs was demonstrated when, under similar laboratory conditions, perylene (a weak promutagen) was converted to 3-nitroperylene, and pyrene (a nonmutagen), at a slower rate, to 1-nitropyrene both nitro-PAHs are direct-acting frameshift mutagens. In a similar experiment, chrysene was not nitrated this is consistent with its low reactivity in the Nielsen reactivity scale (Table 10.30). 

The nitration of PAHs by N02/HN03 also occurs under laboratory conditions approximating plume gases, that is, higher concentrations of gases and deposition on coal fly ash as a substrate. Thus, Hughes and co-workers (1980) reported that BaP and pyrene reacted with 100 ppm of NOz the presence of nitric acid (possibly on the surface of the fly ash) enhanced the rate of reaction. Reactions proceeded more rapidly on silica gel than fly ash substrates, and for pyrene, both mono and dinitro isomers were formed. At the 100 ppm plume gas level, neither NO nor S02 reacted with BaP or pyrene on the substrates studied both PAHs reacted with SO, but products were not characterized. 

Many of the fast chemical reactions discussed in the preceding sections involve at least one reactant which is of low symmetry. The reactions of the solvated electron with nitrate, naphthalene or pyrene are instances where the oxidant has a mirror plane (in the molecular plane) in the accepting orbital. Hence, reaction of the solvated electron with such a scavenger when both are contained in this plane should be slower than in other configurations. Similarly, the contact quenching of fluorescence from naphthalene or 1,2-benzanthracene by carbon tetrabromide [7], or... 

Many polycyclic aromatic amines and aldehydes are commercially available, but their supply is very limited. Preparation of these starting materials is necessary for studying the (3-lactam formation reaction [93]. Nitro compounds are the precursors for the amines. An important task was to prepare polycyclic aromatic nitro compounds, particularly those of chrysene, phenanthrene, pyrene, and dibenzofluorene in good yield. Nitration of these hydrocarbons with concentrated nitric acid in sulfuric acid is a widely used reaction for this purpose. Our research culminated in facile synthesis of polyaromatic nitro derivative 9 starting from polyaromatic hydrocarbons (PAHs) 8 through the use of bismuth nitrate impregnated with clay (Scheme 1) ([94, 95] for some examples of bismuth nitrate-catalyzed reactions... 

Little is known of the actual mechanism. A mode of reaction is possible, in which the oxygen atom at the top of the ozone molecule with a formal positive charge (p. 230) reacts with an electron pair, not localized in a bond but on one carbon atom, and in which the ozone therefore reacts by an electrophilic mechanism (Wibaut, Sixma and Kampschmidt). However, in order to explain the differences between the reaction course for ozonization and for other electrophilic reactions, e.g., bromination and nitration with pyrene, these authors assume also an interaction of one of the other oxygen atoms with the adjacent carbon atom. The net result is, however, about the same as that predicted by the bond localization hypothesis. 

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