Gas-phase reaction of phenol with NO3

The fast gas-phase reaction of NO3 radicals with phenol was found to yield 2-nitrophenol as the only relevant nitration product. The yield of this pro duct was high and independent of the concentration of NO2 at the concentrat ions applied. In the presence of ozone, also significant amounts of 4-nitro phenol and p-benzoquinone were formed. The rate constant of the reaction be tween NO3 radicals and phenol was determined to be 5.8 x 10(-12) cm(3) mole cule(-1) s(-1) The selective formation of 2-nitrophenol (2) is suggested to derive from either the concerted keto-enol tautomerism in the reaction of a phenoxy radical with NO2 or the concerted elimination of nitric acid from a cyclohexa-3,5-diene intermediate.