In this work, the method of boundary and temperature diagrams has been applied to the analysis of an industrial nitration process for the production of a pharmaceutical active ingredient, that is, the nitration of N-(2-phenoxyphenyl) methane sulfonamide to N-(4-nitro, 2-phenoxyphenyl) methane sulfonamide, carried out in homogeneous phase in an indirectly cooled semibatch reactor, in which nitric acid is dosed over an acetic acid solution of the reactant. It has been verified through calorimetric experiments performed in an RC1 equipment that the boundary and temperature diagrams allow the safe selection of operating conditions characterized by a rapid nitric acid consumption, which imply a better control of the reaction. Moreover, it has been shown that using the boundary and temperature diagrams method requires the knowledge of the reaction kinetics, at least in terms of a lumped expression corresponding to an optimum fitting of the experimental data. Such information can be obtained through proper calorimetric experiments (e. g., those performed in an adiabatic Phi-TEC II equipment): uncontrolled approximations on the reaction order of the dosed coreactant can lead to unsafe conclusions, whereas the requirements for the reaction order of the reactant initially charged in the reactor are much less stringent.