In past few years, continuous flow systems have found widespread application in production of active pharmaceutical ingredients (APIs) instead of conventional batch systems. Microreactor technology is increasingly being used for chemical and biochemical processes, as it offers several advantages and leads to process intensification. Implementation of miniaturized equipment improves process sustainability and safety, enables faster production of APIs, lowers solvent and energy consumption and offers a unique way to perform ultrafast, exothermic reactions that allows the execution of reactions which proceed via highly unstable or even explosive intermediates.
In this thesis, the implementation of microreactor technology in the production of various APIs such as ibuprofen, artemisinin, ketamine, linezolid, imatinib, (S)-warfarin and some others was reviewed. Their production in batch and flow systems comprising also microreactors was compared, where photochemistry was found as a promising approach to obtain APIs with high efficiency. Moreover, it is environmentally friendly, as it utilizes light or photons to activate chemical reactions. Depending on which of these reactors the reaction took place in, their yields, conversion, productivity, retention times and reactor volumes were compared. It was observed whether a catalyst needs to be present for a successful synthesis, how many steps are involved in the reaction or if an intermediate isolation is needed, and which number of reactor systems are required for the synthesis. It has been shown that microreactor technology can run reactions much faster, as the isolation of intermediates produced during the reaction is usually not necessary. We can also improve some of the production steps, which include reducing waste by using significantly less material. This brings us closer to the production of fine chemicals and APIs according to the principles of green chemistry.
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