PHOTOCHEMICAL NITRATION OF BENZOIC-ACID DERIVATIVES BY IRRADIATION TO NITRATE IONS

Photochemical nitration of p-hydroxybenzoate, HBA, initiated by UV irradiation to sodium nitrate or sodium nitrite was observed in aqueous solutions. 4-Hydroxy-3-nitrobenzoate was formed, with maximum quantum yields of 0.007 and 0.09 for NaNO3 and NaNO2, respectively. From the dependence of the yields on the pH and concentrations of oxygen and OH-scavengers, we propose a mechanism involving the addition of OH. to the aromatic ring of HBA and electron abstraction from NO2 by the OH. adduct for the photonitration.