Continuous-Flow Microreactor System for Enhanced Selectivity and Safety in Nitrobenzene Nitration.

Dinitrobenzene, a crucial intermediate in pesticide and dye production, is typically synthesized through the exothermic nitration of nitrobenzene. This study presents a continuous-flow microreactor system integrated with micromixers to enhance selectivity and safety in the nitration process. An open-source Python program was developed to precisely control the mass flow rate ratio of nitrobenzene to the mixed acid. By optimizing reaction conditions and employing sodium dodecyl sulfate (SDS) as a surfactant, the selectivity of p-dinitrobenzene was minimized to 0.44%, while hazardous nitrophenol byproducts were reduced to 112 ppm-a significant improvement compared to the 509 ppm observed in traditional batch processes. Compared to traditional batch reactors, the microreactor system significantly lowered p-dinitrobenzene selectivity and minimized nitrophenol and trinitrobenzene formation, highlighting its suitability for industrial-scale applications.