The benzene adiabatic nitration process has been carried out in a pilot plant to enable the studyof this reaction under relevant industrial operating conditions, aiming to increase the reactionconversion and selectivity by reducing the nitrophenols. The influence of relevant operatingparameters such as the reaction temperature, benzene-to-nitric acid molar feed ratio (FB/FN),and stirring speed was studied. The operation ranges covered were as follows: reactiontemperature, 80-135 °C; FB/FN, 0.96-1.15; stirring speed, 360-1700 rpm. The residence timeand the sulfuric acid concentration were fixed at 2 min and 68 wt %, respectively. The productionof cleaner mononitrobenzene (MNB) requires lower nitration temperatures; higher FB/FN ratiosthan in current industrial practice; and high stirring speeds, allowing the interfacial area inthis liquid-liquid mixture to be increased and the decrease in temperature to be compensated.The results reported here highlight the relevance of combining operating parameters to improvethe performance of the reactor. In this study, it was possible to accomplish the same MNBproduction with a significant reduction in nitrophenols concentration. This work presents resultsthat might be useful for conventional industrial benzene adiabatic nitration plants, to improvethe prevention of pollution in this process and allow competitiveness with new plants in fulfilmentof environmental law requirements.
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