Publication Date

5-13-1994

Abstract

The photolysis of aqueous nitrite ion, N02-, yields the free radicals nitric oxide, NO*, and hydroxyl radical, *OH. It has been found by Treinin and Hayon and supported in this laboratory that no net reaction occurs when nitrite is photolyzed in pure water. Zafiriou has extensively studied the solar photolysis of nitrite-containing seawater, and has detected increased partial pressures of NO* during the day, as well as decreased nitrite concentrations, which both suggest that net photolysis of nitrite has occurred. In pure water, the *OH and NO* radicals produced from the photolysis of NO2- presumably recombine and ultimately reproduce NO2-. In the presence of benzene, a known radical scavenger, this process is interrupted and net photolysis of nitrite is observed. This particular scavenging process is of primary interest to this research. Aqueous nitrite saturated with benzene has been photolyzed at 366nm, a wavelength present in solar radiation at which nitrite absorbs. The effect of varying the pH as well as the solvent for maximal extraction of the scavenger product has been studied. Ideally, the identity of the product will be obtained, leading to the quantification of the scavenging process. The reaction has been monitored both spectrophotometrically as well as by a nitrite-specific electrode. In addition to the photochemical reaction, the thermal reaction of nitrite in the presence of benzene has been tested. The scavenging of the hydroxyl radical by benzene has also been studied by producing *OH via hydrogen peroxide and a catalyst. Long range goals include the determination of the quantum yield with respect to nitrite disappearance, with the results compared to the photolysis of nitrous acid, a process that occurs in polluted atmospheres.

Disciplines

Chemistry

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