Aromatic hydrocarbons monocyclic

The transformation of arenes in the troposphere has been discussed in detail (Arey 1998). Their destruction can be mediated by reaction with hydroxyl radicals, and from naphthalene a wide range of compounds is produced, including 1- and 2-naphthols, 2-formylcinnamaldehyde, phthalic anhydride, and with less certainty 1,4-naphthoquinone and 2,3-epoxynaphthoquinone. Both 1- and 2-nitronaphthalene were formed through the intervention of NO2 (Bunce et al. 1997). Attention has also been directed to the composition of secondary organic aerosols from the photooxidation of monocyclic aromatic hydrocarbons in the presence of NO (Eorstner et al. 1997) the main products from a range of alkylated aromatics were 2,5-furandione and the 3-methyl and 3-ethyl congeners. 

Compared with monocyclic aromatic hydrocarbons and the five-membered azaarenes, the pathways used for the degradation of pyridines are less uniform, and this is consistent with the differences in electronic structure and thereby their chemical reactivity. For pyridines, both hydroxylation and dioxygenation that is typical of aromatic compounds have been observed, although these are often accompanied by reduction of one or more of the double bonds in the pyridine ring. Examples are used to illustrate the metabolic possibilities. 

Investigations have examined applications to monocyclic aromatic hydrocarbons and phenols, under both aerobic and anaerobic conditions. 

De Visscher, A., Van Eenoo, P., Drijvers, D., and Van Langenhove, H. Kinetic model for the sonochemical degradation of monocyclic aromatic hydrocarbons in aqneons solntion, J. Phys. Chem., 100(28) 11636-11642, 1996. 

Volkamer, R., T. Etzkorn, A. Geyer, and U. Platt, Correction of the Oxygen Interference with UV Spectroscopic (DOAS) Measurements of Monocyclic Aromatic Hydrocarbons in the Atmosphere, Atmos. Environ., 32, 3731-3747 (1998). 

Dewulf, J., and H. Van Langenhove, Analytical Techniques for the Determination and Measurement Data of 7 Chlorinated Cr and C2-Hydrocarbons and 6 Monocyclic Aromatic Hydrocarbons in Remote Air Masses An Overview, Atmos. Environ., 31, 3291-3307 (1997). 

Dor, F., Y. Le Moullec, and B. Festy, Exposure of City Residents to Carbon Monoxide and Monocyclic Aromatic Hydrocarbons during Commuting Trips in the Paris Metropolitan Area, J. Air Waste Manage. Assoc., 45, 103-110 (1995). 

The shape-selectivity of ZSM-5 is particularly remarkable. Active centres at the inner walls of the catalyst readily release protons to organic reactant molecules forming carbonium ions, which in turn, through loss of water and a succession of C—C forming steps, yield a mixture of hydrocarbons that is similar to gasoline. The feedstock can be methanol, ethanol, corn oil or jojoba oil. The shape-selectivity of this catalyst is particularly striking, as can be seen from the product distribution obtained for the dehydration of three different alcohols (Table 8.2). The product distribution can be understood in terms of the intermediate pore size of ZSM-5, which can accommodate linear alkanes and isoalkanes as well as monocyclic aromatic hydrocarbons smaller than 1, 3, 5-trimethyl benzene. In Table 8.3, we list some of the recent innovations in catalysis, to highlight the important place occupied by molecular-sieve catalysts. 

Mutti, A., Falzoi, M., Romanelli, A., Bocchi, M.C., Ferroni, C. Franchini, 1. (1988) Brain dopamine as a target for solvent toxicity effects of some monocyclic aromatic hydrocarbons. Toxicology, 49, 77-82... 

Cooking activity is also associated with increased concentrations of monocyclic aromatic hydrocarbons. Thus, mean concentrations of benzene, toluene, ethylbenzene, m-, p- and o-xylene, styrene, 1,2, 4-trimethylbenzene and naphthalene were found to be 22.7, 57.0, 6.2, 16.3, 5.6,6.0, 1.4, 5.9 and 0.9 tgnT3 respectively in restaurants (Kim, Harrad and Harrison, 2001). 

Keymeulen, R., De Bruyn, G., and Van Langenhove, H., Headspace gas chromatographic determination of the plant cuticle-air partition coefficients for monocyclic aromatic hydrocarbons as environmental compartment, J. Chromatogr. A, 774, 213-221, 1997. 

The effect of growing plants in polluted environs has also been reported. Monocyclic aromatic hydrocarbons (MAHs benzene, toluene, ethylbenzene and xylenes) were extracted from fruit and vegetables and determined by GC-MS (with selected-ion monitoring mode) by Gorna-Binkul et al. (1996). It was observed that uptake of MAHs depended on the species and took place in different parts of the plant. The highest concentrations of MAHs were found in parsley leaves (m- and p-xylene). 

Gorna-Binkul, A., Keymeulen, R., Van Langenhove, H. and Buszewski, B. (1996) Determination of monocyclic aromatic hydrocarbons in fruit and vegetables by gas chromatography-mass spectrometry Journal of Chromatography A 734(2), 297-302. 

Dor F, Le Moullec Y, Festy B. 1995. Exposure of city residents to carbon monoxide and monocyclic aromatic hydrocarbons during commuting trips in the paris metropolitan area. Journal Of The Air And Waste Management Association 45(2) 103-110. 

Jing, L.H., S.M. Steinberg, and B.J. Johnson Aldehyde and monocyclic aromatic hydrocarbon mixing ratios at an urban site in Las Vegas, Nevada, Journal of the Air Waste Management Association, 51 (2001) 1359-... 

These may occur in water, sediment, or air samples, and several procedures have been used for analytes including halogenated aliphatic compounds, low-molecular-weight aliphatic ethers such as f-butyl methyl ether, and monocyclic aromatic hydrocarbons such as benzene, toluene, ethylbenzene, and xylenes (BTEX). 

Secondary aerosols from monocyclic aromatic hydrocarbons — production and analysis of products formed under simulated conditions in smog chambers (Forstner et al. 1997) ... 

The products from the oxidation of alkylbenzenes under simulated atmospheric conditions have been noted earlier. Both ring epoxides that were highly functionalized and aliphatic epoxides from ring fission were tentatively identified (Yu and Jeffries 1997), and formation of the latter, many of which are mutagenic, may cause further concern over transformation products from monocyclic aromatic hydrocarbons in the atmosphere. 

Dewulf JP, van Langenhove LF (1998) Air/water exchange dynamics of 13 volatile chlorinated Cl- and C2-hydrocarbons and monocyclic aromatic hydrocarbons in the southern North Sea and the Scheldt estuary. Environ Sci Technol 32, 903-911. 

International Standards Organisation (2003c) Water quality - gas-chromatographic determination of a number of monocyclic aromatic hydrocarbons, naphthalene and several chlorinated compounds using purge-and-trap and thermal desorption. ISO 15680 2003. 

The monocyclic aromatic hydrocarbons react in the atmosphere virtually solely with the OH radical (Atkinson, 1989). For example, rate constants for aromatic reactions with OH, 03, and N03 are in the ranges A oh 10-12 — 10-11 cm3 molecule-1 s 1 koi < 10-20 cm3 molecule-1 s-1 kNOj = 10-17 - 10-16 cm3 molecule-1 s-1. The aromatic-OH radi-... 

In ifs 1986 review of tobacco smoke componenfs and fheir relafionship to healfh, fhe lARC (1870) discussed only fhree monocyclic aromatic hydrocarbons, namely, benzene, mefh-ylbenzene (toluene), and efhenylbenzene (sfyrene) ... 

Monocyclic Aromatic Hydrocarbons in Tobacco, Tobacco Smoke, and Tobacco Substitute Smoke... 

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