Continuous Flow Synthesis: Laboratory Approach & Protocol for Scale-up

Amol Kulkarni, Scientist, National Chemical Laboratory

Process intensification is a design philosophy that can lead to substantial benefits in the areas of energy, capital investment, reduced process wastes and safety through radical changes in the processes. Though there are several ways of achieving it, advent of microreactor technology has revolutionized the concept of process intensification. Over last two decades, radical reduction in characteristic flow dimension of the device and hence of the process equipment and subsequently of the process plant has been under exploration and exploitation by developing new, compact multifunctional devices and contacting techniques, which provide very high heat and mass transfer rates and rapid mixing. Typically, microreactors mean the miniaturized and compact process equipment (which include reactors, mixers, heat exchangers, distillation devices, extractors, etc.) which operate in continuous mode. They are used for the reactions and processes where heat transfer, interfacial mass transfer and mixing can help enhance the overall yield in a safer manner. Typically, these are fast and exothermic reactions or the reactions where selectivity is an issue. Representative examples include aromatic nitrations, exothermic oxidations, sulfoxidation, Grignard reactions, Bu-Li chemistry, etc. While the technology is matured in certain application domains, it is still at its infancy in many, including the design and scale-up guidelines. In this talk I will bring out the fundamental of flow synthesis, typical laboratory approach and scale-up guidelines.