Kinetics of nitration of aromatic hydrocarbons in purified acetic anhydride; identification of the electrophile

Abstract

For nitric acid concentrations less than 0.9 mol dm^–3. the rate of nitration in acetic anhydride and the order with respect to nitric acid are sensitive to the prior treatment of the solvent. The conductivity of the solutions suggests that this effect derives from the presence of trace impurities in the reagent grade solvent, and that these on protonation give rise to nitrate ions. Rates of nitration in the purified solvent are particularly sensitive to added nitrate ions and water but are almost unchanged by added acetic acid. A new mechanistic criterion based on the true rate constant for the reaction of the electrophile with the aromatic compound indicates that reaction occurs through the nitronium ion.