Carbonyl atmospheric concentration

Shepson, P. B D. R. Hastie, H. I. Schiff, M. Polizzi, J. W. Botten-heim, K. Anlauf, G. I. Mackay, and D. R. Karecki, Atmospheric Concentrations and Temporal Variations of Cj-C, Carbonyl Compounds at Two Rural Sites in Central Ontario, Atmos. Environ., 25A, 2001-2015 (1991). 

Maroulis, P.J., A.L. Torres, and A.R. Bandy, Atmospheric concentrations of carbonyl sulfide in the south-western and eastern United States. Geophys Res Lett 4, 510, 1977. 

Combination of the available rate constant data with estimates of the atmospheric concentrations of O3, NO3 and OH indicates that the reaction of NO3 with substituted alkenes and terpenes may be the dominant tropospheric oxidation process for these species. Formation of carbonyl nitrates in the reactions could be important in the long-range transport of odd nitrogen. 

In a polluted or urban atmosphere, O formation by the CH oxidation mechanism is overshadowed by the oxidation of other VOCs. Seed OH can be produced from reactions 4 and 5, but the photodisassociation of carbonyls and nitrous acid [7782-77-6] HNO2, (formed from the reaction of OH + NO and other reactions) are also important sources of OH ia polluted environments. An imperfect, but useful, measure of the rate of O formation by VOC oxidation is the rate of the initial OH-VOC reaction, shown ia Table 4 relative to the OH-CH rate for some commonly occurring VOCs. Also given are the median VOC concentrations. Shown for comparison are the relative reaction rates for two VOC species that are emitted by vegetation isoprene and a-piuene. In general, internally bonded olefins are the most reactive, followed ia decreasiag order by terminally bonded olefins, multi alkyl aromatics, monoalkyl aromatics, C and higher paraffins, C2—C paraffins, benzene, acetylene, and ethane. 

Acetates. Anhydrous iron(II) acetate [3094-87-9J, Ee(C2H202)2, can be prepared by dissolving iron scraps or turnings in anhydrous acetic acid ( 2% acetic anhydride) under an inert atmosphere. It is a colorless compound that can be recrystaUized from water to afford hydrated species. Iron(II) acetate is used in the preparation of dark shades of inks (qv) and dyes and is used as a mordant in dyeing (see Dyes and dye intermediates). An iron acetate salt [2140-52-5] that is a mixture of indefinite proportions of iron(II) and iron(III) can be obtained by concentration of the black Hquors obtained by dissolution of scrap iron in acetic acid. It is used as a catalyst of acetylation and carbonylation reactions. 

The first homoleptic, dinuclear platinum(I) carbonyl complex [Pt2(CO)6]2+ has been prepared by dissolving Pt02 in concentrated sulfuric acid under a CO atmosphere.92,93 The structure is rigid on the NMR time scale at room temperature. DFT studies suggested a staggered structure for the dimer.92,93... 

Solutions containing the [Au(GO)]+ cation are also obtained by treatment of commercial gold(m) oxide AU2O3 with concentrated sulfuric acid in a CO atmosphere. Depending on the reaction conditions, both [Au(CO)]+ and [Au(CO)2]+ are present in these solutions as demonstrated by IR and NMR spectroscopy. The solution catalyzes the carbonylation of terminal olefins and a mechanism has been proposed for the process (Equation (55)). This... 

In many respects the apparently analogous reduction of nitroarenes with triruthenium dodecacarbonyl under basic phase-transfer conditions is superior to that of the iron carbonyl-mediated reductions. However, the difference in the dependence of the two processes on the concentration of the aqueous sodium hydroxide and the pressure of the carbon monoxide suggests that they may proceed by different mechanisms. Although the iron-based system is most effective under dilute alkaline conditions in the absence of carbon monoxide, the use of 5M sodium hydroxide is critical for the ruthenium-based system, which also requires an atmosphere of carbon monoxide [11]. The ruthenium-based reduction has been extended to the... 

As the supported glycol catalysts worked better in promoting reactions in a single solvent system, we explored the direct carbonylation of benzyl halides using an alcohol solvent, base, and cobalt carbonyl. Our initial experiments concentrated on the reaction of benzyl bromide at room temperature and one atmosphere carbon monoxide. We chose sodium hydroxide as the base, methanol as the solvent, and looked at the product distribution. We were interested in the selectivity to ester and the reactivity of this system. The results are given in Table III. 

In the Favorski reaction [8], etbyne is coupled with a carbonyl compound in the presence of powdered alkali hydroxide suspended in an organic solvent, in which the acetylene has good solubility. Some acetylenic carbinols, derived from ketones, can be obtained in high yields by introducing acetylene at atmospheric pressure. The active intermediate possibly is a metal acetylide formed in low concentration. 

Wang, B Lee, S.C. and Ho, K.F. (2007) Characteristics of carbonyls concentrations and source strengths for indoor and outdoor residential microenvironments in China. Atmospheric Environment, 41 (13), 2851-61. 

As Barr et al. (2003) pointed out, the importance of such emissions is determined mainly by their impact on the three processes taking place in the atmosphere. The first consists in that such NMHCs as isoprene form in the course of carboxylization in plants and contribute much thereby to the formation of biospheric carbon cycle. The second process is connected with NMHCs exhibiting high chemical activity with respect to such main oxidants as hydroxyl radicals (OH), ozone (03), and nitrate radicals (N03). Reactions with the participation of such components result in the formation of radicals of alkylperoxides (R02), which favor efficient transformation of nitrogen monoxide (NO) into nitrogen dioxide (N02), which favors an increase of ozone concentration in the ABL. Finally, NMHC oxidation leads to the formation of such carbonyl compounds as formaldehyde (HCHO), which stimulates the processes of 03 formation. Finally, the oxidation of monoterpenes and sesquiterpenes results in the intensive formation of fine carbon aerosol with a particle diameter of <0.4 pm... 

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