PHOTOLYSIS OF SUBSTITUTED NAPHTHALENES ON SiO2 AND Al2O3

Barbas, John T.; Sigman, Michael E.; Buchanan, A. C.; Chevis, Eddie A.

doi:10.1111/j.1751-1097.1993.tb09541.x

Cited by 36 publications

(25 citation statements)

References 19 publications

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“…Analogous outcomes are observed under a variety of other conditions [oxidation catalyzed by TiO 2 , by SiO 2 (27), and by Fe 2 O 3 (28)]. This uniformity in outcome argues that the oxidation of naphthalene will generically yield phthalic acid as a metastable intermediate (29).…”

Section: Geologymentioning

confidence: 61%

The missing organic molecules on Mars

Benner

Devine

Matveeva

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

377

350

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GC-MS on the Viking 1976Mars missions did not detect organic molecules on the Martian surface, even those expected from meteorite bombardment. This result suggested that the Martian regolith might hold a potent oxidant that converts all organic molecules to carbon dioxide rapidly relative to the rate at which they arrive. This conclusion is influencing the design of Mars missions. We reexamine this conclusion in light of what is known about the oxidation of organic compounds generally and the nature of organics likely to come to Mars via meteorite. We conclude that nonvolatile salts of benzenecarboxylic acids, and perhaps oxalic and acetic acid, should be metastable intermediates of meteoritic organics under oxidizing conditions. Salts of these organic acids would have been largely invisible to GC-MS. Experiments show that one of these, benzenehexacarboxylic acid (mellitic acid), is generated by oxidation of organic matter known to come to Mars, is rather stable to further oxidation, and would not have been easily detected by the Viking experiments. Approximately 2 kg of meteorite-derived mellitic acid may have been generated per m 2 of Martian surface over 3 billion years. How much remains depends on decomposition rates under Martian conditions. As available data do not require that the surface of Mars be very strongly oxidizing, some organic molecules might be found near the surface of Mars, perhaps in amounts sufficient to be a resource. Missions should seek these and recognize that these complicate the search for organics from entirely hypothetical Martian life.Viking ͉ organic compounds ͉ exobiology ͉ astrobiology

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Section: Geologymentioning

confidence: 61%

The missing organic molecules on Mars

Benner

Devine

Matveeva

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

377

350

View full text Add to dashboard Cite

show abstract

“…In the troposphere, direct photolysis of PAHs associated with solid surfaces is a potentially important process. 1,230,231 The chemistry of direct photolytic PAH decomposition has been discussed elsewhere for PAHs associated with organic aerosols, [232][233][234][235][236][237][238] inorganic substrates [239][240][241][242][243][244][245][246][247][248] and the air-ice interface. 249,250 Therefore, photolysis of surface-bound PAH will not be covered in this review.…”

Section: 2142mentioning

confidence: 99%

Chemical reactivity and long-range transport potential of polycyclic aromatic hydrocarbons – a review

2013

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Polycyclic aromatic hydrocarbons (PAHs) are of considerable concern due to their well-recognised toxicity and especially due to the carcinogenic hazard which they present. PAHs are semi-volatile and therefore partition between vapour and condensed phases in the atmosphere and both the vapour and particulate forms undergo chemical reactions. This article briefly reviews the current understanding of vapour-particle partitioning of PAHs and the PAH deposition processes, and in greater detail, their chemical reactions. PAHs are reactive towards a number of atmospheric oxidants, most notably the hydroxyl radical, ozone, the nitrate radical (NO3) and nitrogen dioxide. Rate coefficient data are reviewed for reactions of lower molecular weight PAH vapour with these species as well as for heterogeneous reactions of higher molecular weight compounds. Whereas the data for reactions of the 2-3-ring PAH vapour are quite extensive and generally consistent, such data are mostly lacking for the 4-ring PAHs and the heterogeneous rate data (5 and more rings), which are dependent on the substrate type and reaction conditions, are less comprehensive. The atmospheric reactions of PAH lead to the formation of oxy and nitro derivatives, reviewed here, too. Finally, the capacity of PAHs for long range transport and the results of numerical model studies are described. Research needs are identified.

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“…These two compounds were not detected in the dark baseline (D-1) experiments, and the highest concentrations are associated with experiments that included VOC (w/naphthalene) additions (D-2, L-2b, L-1b). Phthalic acid has been shown to be the only major product from the photolysis of naphthalene on SiO 2 and Al 2 O 3 surfaces in air (Barbas et al, 1993), and more recent chamber experiments have identified phthalic anhydride and phthaldialdehyde as a transformation product of the OH radical initiated reactions of naphthalene (Wang et al, 2007).…”

Section: Poc Concentrationsmentioning

confidence: 99%

Secondary organic aerosol production from modern diesel engine emissions

Samy

Zielińska

2010

Atmos. Chem. Phys.

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Abstract. Secondary organic aerosol (SOA) production was observed at significant levels in a series of modern diesel exhaust (DE) aging experiments conducted at the European Outdoor Photoreactor/Simulation Chamber (EUPHORE). The greatest production occurred in DE with toluene addition experiments (>40%), followed by DE with HCHO (for OH radical generation) experiments. A small amount of SOA (3%) was observed for DE in dark with N2O5 (for NO3 radical production) experiments. The analysis for a limited number (54) of polar organic compounds (POC) was conducted to assess the composition of modern DE and the formation of photochemical transformation products. Distinct POC formation in light versus dark experiments suggests the role of OH initiated reactions in these chamber atmospheres. A trend of increasing concentrations of dicarboxylic acids in light versus dark experiments was observed when evaluated on a compound group basis. The four toluene addition experiments in this study were performed at different [tol]o/[NOx]o ratios and displayed an average SOA %yield (in relation to toluene) of 5.3±1.6%, which is compared to past chamber studies that evaluated the impact of [tol]o/[NOx]o on SOA production in more simplified mixtures.

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PHOTOLYSIS OF SUBSTITUTED NAPHTHALENES ON SiO₂ AND Al₂O₃

Cited by 36 publications

References 19 publications

The missing organic molecules on Mars

The missing organic molecules on Mars

Chemical reactivity and long-range transport potential of polycyclic aromatic hydrocarbons – a review

Secondary organic aerosol production from modern diesel engine emissions

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