Single- and two-phase nitration of mononitrotoluenes

The homogeneous rates of nitration of ortho-, meta- and para-nitrotoluene in aqueous sulphuric acid have been determined over a range of temperatures. Some difficulties were experienced in measuring the rate of nitration of ortho-nitrotoluene because of competition between nitration of the latter and one or more side-reactions, the exact nature of which were not determined. Some possible explanations for this phenomenon are discussed. Combination of the experimental rate data with those published in the literature has enabled predictions to be made of values for the observed second order rate constant k2 as a function of temperature and H2SO4–H2O composition. [Continues.