Atmospheric Reactions of Selected Nitrogen and Sulfur Compounds

Atmospheric Reactions of Selected Nitrogen and Sulfur Compounds 

Reduced nitrogen compounds emitted into the atmosphere include ammonia (NH3) and hydrogen cyanide (HCN), and possibly their higher homologues such as the aliphatic and aromatic amines RNH2, RR NH, and RR R N and the nitriles RCN, where R, R, R = alkyl or aryl group. 

The major atmospheric reactions of the amines identified to date involve the gas-phase reaction with the OH radical  

The reactions of amines with the OH radial are rapid, with lifetimes during daylight hours being on the order of hours. Ammonia, however, being highly soluble and reactive with atmospheric acids, will be removed preferentially by those routes rather than through reaction with the OH radical. Particulate-nitrate salts will undergo dry and/or wet deposition to surfaces. 

The available experimental data suggest that this class of reduced nitrogen compounds will react mainly with OH radicals under tropospheric conditions. Hydrogen cyanide (HCN) reacts only slowly with OH radicals, with a room-temperature rate constant at atmospheric pressure of 3 X 10-14 cm3 molecule-1 s-1 (Atkinson, 1989). For the organic nitriles, the available evidence shows that the OH reaction occurs via H-atom abstraction from the alkyl groups, for example, 

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VIII. Atmospheric Reactions of Selected Nitrogen and Sulfur Compounds... 

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