this invention relates to an improvement in an process for dinitrating 3 - nitrobenzotrifluoride and 4 - hal0 - 3 - nitrobenzotrifluoride compounds wherein the mononitrobenzotrifluoride composition is contacted with a mixture comprising sulfuric and nitric acid . the improvement constituting the basis of this invention comprises carrying out the dinitration with the sulfuric acid being present in at least a catalytic proportion but not exceeding about 65 mole percent in said mixture .