Phenols are transformed into nitrophenols by the combined action of ozonized oxygen and nitrogen dioxide (Kyodai nitration) in different solvents. Dipole moments of the solvents were correlated with the ortho/para nitration ratio with phenol, showing an influence of the polarity of the solvent on the ortho/para nitration selectivity. A Hammett rho of -0.72 was obtained in the Kyodai nitration of 4-substituted phenols. These facts suggest the formation of a charge-transfer complex which evolves to the addition of NO3 to phenols followed by elimination of nitric acid to give the final nitrophenols. The position of the nitro group in nitrophenols found in air samples may be indicative of a gas- or a liquid-phase nitration occurring in the troposphere
Barletta, B., Bolzacchini, E., Meinardi, S., Orlandi, M., Rindone, B. (2000). The NO3 radical-mediated liquid phase nitration of phenols with nitrogen dioxide. ENVIRONMENTAL SCIENCE & TECHNOLOGY, 34(11), 2224-2230 [10.1021/es990844m].
The NO3 radical-mediated liquid phase nitration of phenols with nitrogen dioxide
BOLZACCHINI, EZIO;ORLANDI, MARCO EMILIO;RINDONE, BRUNO
2000
Abstract
Phenols are transformed into nitrophenols by the combined action of ozonized oxygen and nitrogen dioxide (Kyodai nitration) in different solvents. Dipole moments of the solvents were correlated with the ortho/para nitration ratio with phenol, showing an influence of the polarity of the solvent on the ortho/para nitration selectivity. A Hammett rho of -0.72 was obtained in the Kyodai nitration of 4-substituted phenols. These facts suggest the formation of a charge-transfer complex which evolves to the addition of NO3 to phenols followed by elimination of nitric acid to give the final nitrophenols. The position of the nitro group in nitrophenols found in air samples may be indicative of a gas- or a liquid-phase nitration occurring in the troposphere
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