Transformations of Benzene Photoinduced by Nitrate Salts and Iron Oxide |
| |
| Authors: | Daniele?Borghesi Davide?Vione Valter?Maurino Email author" target="_blank">Claudio?MineroEmail author |
| |
| Institution: | (1) Dipartimento di Chimica Analitica, Università di Torino, Via P. Giuria 5, 10125 Torino, Italy |
| |
| Abstract: | This paper reports the results of a study on the transformation of benzene in the presence of solid nitrate salts (NaNO3, NH4NO3) under irradiation in a gas-solid photoreactor. Sodium and ammonium nitrate have been chosen as representative of the composition
of atmospheric particulate, benzene as a model aromatic molecule. The purpose is to simulate the transformations that aromatic
compounds undergo on the surface of dispersed particles in the atmosphere. Irradiation of sodium nitrate causes hydroxylation
and nitration of benzene, yielding phenol and nitrobenzene. This is most likely due to the generation of •OH and •NO2 radicals upon nitrate photolysis, with •OH + O2 leading to the formation of phenol and •OH + •NO2 yielding nitrobenzene. The percentage of oxygen in the reaction environment influences the transformation pathways, with
phenol formation being favoured and nitrobenzene formation depressed by high O2 concentration. In the presence of hematite (α-Fe2O3, another component of atmospheric particulate) very relevant formation of nitrobenzene takes place even with 21% oxygen (simulated
air), indicating that the interaction between hematite and nitrate can lead to the formation of aromatic nitroderivatives
on the surface of atmospheric particulate. The effect of hematite is possibly due to protonation of peroxynitrite, formed
upon nitrate photoisomerisation, to peroxynitrous acid, a powerful nitrating agent. A similar effect leads to relevant formation
of nitrobenzene under atmospheric conditions upon irradiation of the acid salt ammonium nitrate. |
| |
| Keywords: | aromatic pollutants atmospheric photochemistry heterogeneous reactions particulate matter |
| 本文献已被 SpringerLink 等数据库收录！ |
|
