- Study of the atmospheric chemistry of 2-formylcinnamaldehyde
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2-Formylcinnamaldehyde is a significant product of the reaction of naphthalene with OH radicals, and its photolysis and gas-phase reactions with O3, NO3 radicals, and OH radicals have been investigated in this work. 2-Formylcinnamaldehyde was observed to undergo photolysis by black lamps, with a photolysis rate of 0.14 × J(NO2), where J(NO2) is the NO2 photolysis rate. The measured rate constants for the reactions of 2-formylcinnamaldehyde with O3, NO3 radicals, and OH radicals (in units of cm3 molecule-1 s-1) were 1.8 × 10-18, 4.3 × 10-14, and 2.1 × 10-11, respectively, with those for the O3 and NO3 reactions being for the E-isomer. 2-Formylcinnamaldehyde was observed to undergo significant adsorption and desorption from the reaction chamber Teflon film walls, and the photolysis rate and rate constants are subject to significant uncertainties. In the atmosphere, the dominant chemical loss processes for 2-formylcinnamaldehyde will be photolysis during daylight hours and reaction with NO3 radicals during nighttime. Phthaldialdehyde and glyoxal were observed as products of the OH radical and O3 reactions, and photolysis of E-2- formylcinnamaldehyde led to formation of Z-2-formylcinnamaldehyde plus two other molecular weight 160 isomers. The present results are compared with previous literature data, and reaction mechanisms are discussed.
- Aschmann, Sara M.,Arey, Janet,Atkinson, Roger
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p. 7876 - 7886
(2013/09/23)
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- Titanium dioxide photocatalyzed oxygenation of naphthalene and some of its derivatives
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The titanium dioxide photocatalyzed oxygenation of naphthalene in water gives (E,Z)-2-formylcinnamaldehydes and 1,4-naphthoquinone besides traces of naphthols. 1-Substituted naphthalenes (both with an electron-withdrawing and -donating group) are likewise oxidised at about the same rate with a similar product distribution. The evidence obtained supports the hypothesis that the reaction involves transfer of a hydroxy group to naphthalene and reduction of oxygen to superoxide followed by coupling of the two species. In organic solvents the reaction is slower, more selective (a cyano group inhibits the reaction) and leads to phthalic anhydride and 1,4-naphthoquinone. The relation with the solvent-dependent course of the ozonation of the same substrates is commented upon.
- Soana, Federica,Sturini, Michela,Cermenati, Laura,Albini, Angelo
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p. 699 - 704
(2007/10/03)
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- Reaction of naphthalene and its derivatives with hydroxyl radicals in the gas phase
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Naphthalene is the most abundant polycyclic aromatic hydrocarbon (PAH) found in urban air. It is reactive in the atmosphere under ambient conditions, its chief reaction partner being the hydroxyl radical, OH·. In this work, the reactions of OH· with naphthalene, 1- and 2-naphthol, and 1- and 2-nitronaphthalene were studied in a 9.4 m3 smog chamber. Relative rates of reaction accorded well with previous studies and allowed estimates to be made of the atmospheric lifetimes of these compounds. Numerous oxidation products were identified, and mechanisms proposed for their formation were based on the further transformation of benzocyclohexadienyl radicals formed by addition of OH· to naphthalene. The naphthols and nitronaphthalenes were deduced not to be on the major reaction pathway to the more oxidized products. Because of the high reactivity of PAH in air, we suggest that priority be given to identifying and quantitating their reaction products, some of which may be relatively persistent air toxics. Naphthalene is the most abundant polycyclic aromatic hydrocarbon (PAH) found in urban air. It is reactive in the atmosphere under ambient conditions, its chief reaction partner being the hydroxyl radical, OH·. In this work, the reactions of OH· with naphthalene, 1- and 2-naphthol, and 1- and 2-nitronaphthalene were studied in a 9.4 m3 smog chamber. Relative rates of reaction accorded well with previous studies and allowed estimates to be made of the atmospheric lifetimes of these compounds. Numerous oxidation products were identified, and mechanisms proposed for their formation were based on the further transformation of benzocyclohexadienyl radicals formed by addition of OH· to naphthalene. The naphthols and nitronaphthalenes were deduced not to be on the major reaction pathway to the more oxidized products. Because of the high reactivity of PAH in air, we suggest that priority be given to identifying and quantitating their reaction products, some of which may be relatively persistent air toxics.
- Bunce, Nigel J.,Liu, Lina,Zhu, Jiang,Lane, Douglas A.
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p. 2252 - 2259
(2007/10/03)
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- Preparation and Photoisomerization of 2-Formylcinnamaldehyde in Solution
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Naphthalene, in dilute aqueous solution, reacts with ozone to form one or both isomers of 2-formylcinnamaldehyde; an equilibrium mixture of the isomers also results upon irradiation of the E-isomer with long wavelength ultraviolet light.
- Larson, Richard A.,Garrison, Wendy J.,Marley, Karen A.
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p. 3987 - 3990
(2007/10/02)
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- OZONOLYSIS BY MICROWAVE DISCHARGE OF OXYGEN OF NAPHTHALENE ADSOBED ON FLORISIL
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Microwave discharge of O2 produces O(3P) atoms which form O3 on florisil surface.Reaction with adsorbed naphthalene results in o-formylcinnamaldehydes as the main product.
- Zadok, Elazar,Rubinraut, Sara,Mazur, Yehuda
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p. 4175 - 4176
(2007/10/02)
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