A potential micro-industrial plant for on-chip catalytic hydrogenation of organic liquid

A micro-industrial plant of a gas-liquid-solid micro-reaction system is designed and built (constructed), that employs a simple on-chip, single-line monolithic microreactor system constructed in silicon for the heterogeneous hydrogenation of organic liquids, coupled with an in-situ microbubble slug/annular regime generation. The integration of catalyst (Pd) on the channel walls is well described. The organic liquid (nitrobenzene in this case) was syringe-pumped as the main channel flow, whilst the hydrogen gas was introduced through a side pore. Using the nitrobenzene as organic liquid, a reactor channel of 200 µm width and a gas inlet channel of 5 µm width in this work, the gas inlet angle, the liquid in-flow velocity and gas in-flow rate were monitored to optimize the bubble slug (annular flow regime) generation. The 90^◦ inlet channel was found to be the optimum angle for the creation of a thin liquid film on the channel wall. The operation of the system for the execution of reactions under pressure, and the system cleaning and system shut-down after experiments, and emergency shutdown procedures for safety purposes are presented. Nitrobenzene hydrogenation reaction yields as high as 93% were achieved with the microplant.