On the effect of pH in aromatic photonitration upon nitrate photolysis.
This paper studies the pH effect on the photonitration of catechol, 1-naphthol, naphthalene, and benzene. The pH trend is influenced by the generation of HNO(2) and peroxynitrous acid (HOONO) upon nitrate photolysis. HNO(2) can be involved in a direct and an indirect nitration process. Direct nitration follows the pH distribution of HNO(2) (flexus around 3). Indirect nitration, possibly involving nitrosation+oxidation, would be highest around pH3. HOONO can be involved in electrophilic nitration, where the initial formation rate of the nitroderivatives is proportional to [H(+)], or take part in nitration directly, in which case a less important pH effect in photonitration is observed. The relative importance of the various nitration pathways for each substrate determines the resulting pH effect in photonitration upon nitrate photolysis.
Minero
Claudio
C
Dipartimento di Chimica Analitica, Università di Torino, Via P. Giuria 5, 10125 Torino, Italy.
Bono
Francesca
F
Rubertelli
Francesca
F
Pavino
Davide
D
Maurino
Valter
V
Pelizzetti
Ezio
E
Vione
Davide
D
D001554:Benzene / Q000494:pharmacology*; D002396:Catechols / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D007259:Infrared Rays; D009281:Naphthalenes / Q000494:pharmacology*; D009284:Naphthols / Q000494:pharmacology*; D009566:Nitrates / Q000737:chemistry*; D010782:Photolysis / Q000187:drug effects*
D002396:Catechols; D009281:Naphthalenes; D009284:Naphthols; D009566:Nitrates; C031721:naphthalene; C029350:1-naphthol; D001554:Benzene; C034221:catechol