Continuous processing, or flow chemistry, has been used for decades in the chemical industry. Recently, it has been gaining interest in the pharmaceutical and fine chemical industries due to the inherent increased safety, improved product quality and cost efficiency, and overall production flexibility. Continuous flow chemistry opens options with exothermic synthetic steps that are not possible in batch reactors, and new developments in flow reactor design provide alternatives for reactions that are mixing limited in batch reactors.
Continuous flow chemistry begins with two or more streams of different materials pumped at a pre-determined flow rates into a single chamber, tube or in some cases a microreactor. The product is collected at the outlet in a flask or container of some type or directed to another flow reactor loop for a secondary step and so on for as many steps required to generate the final product. Only small amounts of material are needed, which dramatically enhances process safety. A higher reaction temperature is generally possible thanks to shorter reaction time (residence time). This often results in better product quality and higher yield.