Aqueous Phase Reactivity of Nitrate Radicals (NO3) Toward Dicarboxylic Acids

Abstract

Abstract Laser photolysis technique was used to study the reactivity of nitrate radical towards four dicarboxylic acids. The temperature dependence of the reactions was investigated in the range from 278K to 318K. The effect of the acid-base equilibrium was examined by measuring the activation parameters of the dissociated and undissociated acids at different pH. For droplets or aerosols under moderate acidic conditions, the charge exchange reaction at the carboxylate group might compete with the oxidation by the hydroxyl radical. On liquid particles enriched in nitrate (such as a deliquescent ammonium nitrate), the lifetime of carboxylic groups towards the NO3 radical may be as short as few hours (or less).