The effect of O2 and NO2 on the ring retaining products of the reaction of toluene with hydroxyl radicals

The reaction of toluene with hydroxyl radicals produces ring retaining products either from H-atom abstraction from the methyl group: benzaldehyde and benzylalcohol or from the addition of the hydroxyl radical to the aromatic ring: o-, m+p-cresol. The yields obtained in experiments carried out in nitrogen and in air matrix were statistically not significantly different. The addition of NO2 to the reactants had no effect on the formed o-cresol, indicating that reaction of the hydroxy-methylcyclohexadienyl radical with NO2 is not contributing significantly to the formation of o-cresol. This is in agreement with recent studies postulating the more stable toluene oxide as the intermediate resulting from the reaction of hydroxy-methylcyclohexadienyl with oxygen rather than the peroxy radical. m-nitrotoluene was the major nitrotoluene formed in the presence of NO2, increasing linearly with increasing the initial concentration of NO2 with zero intercept. The observed 2-methyl 1,4 benzoquinone and traces of phenol and benzene were determined to be secondary products.