(17g) 3D Flow Reactors: Flow, Hydrodynamics, Processes and Performance

Use of miniaturized devices for continuous flow synthesis is now a well known and still more of an art. Miniaturization is necessary to overcome the transport limitations and for rapid mixing. However for enhancing the capacity or production rate, numbering up or increasing the throughput by increasing the volumes while maintaining the miniaturized features is necessary. A vast body of literature is available on the microreactors, their advantages, performance for variety of reactions for synthesis of chemicals and nanomaterials. Several reports exist on the use of miniaturized devices for pilot scale or commercial scale production. Among many, the most prominent candidates that are used for capacity enhancement include, the Corning’s Advanced^TMFlow Reactor, Alfa Laval Plate Reactor, ESK’s ceramic flow reactors and heat exchangers, Hitachi reactors, etc. Here we report high throughput miniaturized flow reactors for carrying out exothermic chemical reactions.

The system comprises of sequence of metallic converging or diverging units aligned either in axisymmetric or non-axisymmetric manner. This configuration is among one of the MAGIC devices (Modular, AGile Intensified and Continuous) that aims at developing high performance low cost devices for processing of fine chemicals and pharmaceutical intermediates. Initial analysis of flow and hydrodynamics (pressure drop, residence time distribution, mass transfer, heat transfer) and the detailed CFD simulations were used for finalizing the geometry that can be used for conducting single phase and multiphase reactions. Upon finalizing the geometry, a highly exothermic aromatic nitration (heat of reaction » -172 kJ/mol) involving fuming nitric acid was studied for the synthesis of the desired isomer at a scale of 10 g/min. The kinetics of nitration were explored and used for further simulating the temperature and velocity variation over the entire sequence. The analysis of the nitration reaction clearly indicated that simple geometries and detailed understanding of the flow can yield a very feasible and economically viable continuous flow option with very small pay back period.