Scale-up and safety of toluene nitration in a meso-scale flow reactor

In this study, toluene nitration was scaled up in a meso-scale flow reactor and safety was considered. The exothermic characteristic was demonstrated in a batch calorimeter. Parallel flow was observed in the flow channel and numerical simulation was carried out to show the hydrodynamics. Mass transfer coefficient of the reactor mixer was determined. The effects of flow rates, temperatures and molar ratios on toluene nitration in the flow reactor were analyzed. The conversion of toluene increased from 26% to 86% with the increase of flow rates while the impacts of temperatures and molar ratios were comparatively small. A productivity of 2572 kg/a could be achieved by this meso-scale flow reactor but the highest overtemperature inside the channel was more than 21.3 ∘C. A comparison between performances of the batch calorimeter and the flow reactor was also presented. The finding of this study can serve as a reference to design inherently safer meso-scale flow reactors for kinetically fast and highly-exothermic reactions.