Nitrate radical reaction with organic compound

Dlugokencky, E.J., Howard, C.J. Studies of nitrate radical reactions with some atmospheric organic compounds at low pressures. J. Phys. Chem. 93, 1091-1096 (1989)... 

Alfassi, Z. B S. Padmaja, P. Neta, and R. E. Huie, Rate Constants for Reactions of NO, Radicals with Organic Compounds in Water and Acetonitrile, J. Phys. Chem., 97, 3780-3782 (1993). Allen, H. C., J. M. Laux, R. Vogt, B. J. Finlayson-Pitts, and J. C. Hemminger, Water-Induced Reorganization of Ultrathin Nitrate Films on NaCI—Implications for the Tropospheric Chemistry of Sea Salt Particles, J. Phys. Chem., 100, 6371-6375 (1996). Allen, H. C., D. E. Gragson, and G. L. Richmond, Molecular Structure and Adsorption of Dimethyl Sulfoxide at the Surface of Aqueous Solutions, J. Phys. Chem. B, 103, 660-666 (1999). Anthony, S. E R. T. Tisdale, R. S. Disselkamp, and M. A. Tolbert, FTIR Studies of Low Temperature Sulfuric Acid Aerosols, Geophys. Res. Lett., 22, 1105-1108 (1995). 

The OH radical reactions with a number of nitrogen-, sulfur- and phosphorus-containing organic compounds appear to proceed, at least in part, by an initial addition reaction (Atkinson, 1989,1994 Kwok et al., 1996), although the products observed may in some cases be those expected from H-atom abstraction. Note that the recent study of Talukdar et al. (1997) indicates that the reactions of the OH radical with alkyl nitrates proceed only by H-atom abstraction, and Table 14.1 gives the applicable substituent group factors for alkyl nitrates. 

Gas- and particle-phase organic compounds can undergo chemical change via a number of routes.76,77 For gas-phase chemicals, these involve photolysis and reaction with the hydroxyl (OH) radical, reaction with the nitrate (N03) radical and reaction with ozone (03).76,77 84 The formation of OH radicals, N03 radicals and 03 in the troposphere, and the requirements for photolysis to occur in the troposphere, are briefly discussed below, prior to presenting the experimental data for the PCBs, PCDDs and PCDFs for these processes. 

As discussed in the previous sections reaction of NO3 radicals with organic compounds results in the formation of HNO3 and organic nitrates. In the stratosphere CIO radicals react with N02 to give C10N02 which undergoes hydrolysis. 

Atkinson, R. (1991), Kinetics and mechanisms of the gas-phase reactions of the nitrate (NO3) radical with organic compounds, J. Phys Chem. Ref. Data, 20, 459-507. 

In addition to reactions with HO, tropospheric organic compounds may be oxidized by ozone (via ozonation of non-aromatic carbon/carbon double bonds, Atkinson 1990) and in some cases by reaction with nitrate radical, described below. Table I gives representative trace-gas removal rates for these three processes. In spite of these competing reactions, HO largely serves as... 

Chemical radicals—such as hydroxyl, peroxyhydroxyl, and various alkyl and aryl species—have either been observed in laboratory studies or have been postulated as photochemical reaction intermediates. Atmospheric photochemical reactions also result in the formation of finely divided suspended particles (secondary aerosols), which create atmospheric haze. Their chemical content is enriched with sulfates (from sulfur dioxide), nitrates (from nitrogen dioxide, nitric oxide, and peroxyacylnitrates), ammonium (from ammonia), chloride (from sea salt), water, and oxygenated, sulfiirated, and nitrated organic compounds (from chemical combination of ozone and oxygen with hydrocarbon, sulfur oxide, and nitrogen oxide fragments). ... 

As shown, NO3 radical leads to different chemistry than does HO radical the peroxy radical can decompose to yield several products, including acetaldehyde, formaldehyde, 1,2-propanediol dinitrate (PDDN), nitroxyperoxypropyl nitrate (NPPN), and a-nitrooxyacetone. The reactions of the peroxy radicals with NO , species can lead to highly functionalized (and oxidized) organic compounds. 

Aldehydes are emitted directly into the atmosphere from a variety of natural and anthropogenic sources and are also formed in situ from the atmospheric degradation of volatile organic compounds (VOCs). The atmospheric fate of aldehydes is controlled by photolysis and reaction with hydroxyl (OH) or nitrate (NO3) radicals and, in the case of unsaturated compounds, reaction with ozone (Atkinson, 1994). The photolysis of aldehydes is of particular importance because it is a source of free radicals in the troposphere, and thus may significantly influence the oxidizing capacity of the lower atmosphere (Finlayson-Pitts and Pitts, 1986). 

Aldehydes are emitted by combustion processes and also are formed in the atmosphere from the photochemical degradation of other organic compounds. Aldehydes undergo photolysis, reaction with OH radicals, and reaction with N03 radicals in the troposphere. Reaction with N03 radicals is of relatively minor importance as a loss process for these compounds, but can be a minor contributor to the H02 (from formaldehyde) and peroxyacetyl nitrate (PAN) formation during nighttime hours (Stockwell and Calvert, 1983 Cantrell et al., 1985). Thus, the major loss processes involve photolysis and reaction with OH radicals. 

Note that this reaction pathway will operate only in the nighttime, as during the daytime NO3 photolyzes rapidly. The NO3 radical formed during the nighttime also reacts with a series of organic compounds, producing organic nitrates. Aqueous-phase production of ni-... 

Detailed reviews of the reactions of hydroxyl radicals, ozone, and nitrate radicals with different classes of organic compounds are available. In addition, lUPAC sponsors a continuing program to evaluate and compile kinetic information on these reactions and these reports are published in the Journal of Physical Chemical reference Data. The analysis lists among other data the preferred rate constants and where possible, information on temperature effects. A recent analysis focuses primarily on reactions of hydroxyl and nitrate radicals. This extensive database provides an opportunity for developing systematic approaches to predicting reaction rates. 

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