Abstract
AbstractMolecular oxygen (O2) is the ultimate “green” oxidant for organic synthesis. There has been recent intensive research within the synthetic community to develop new selective liquid phase aerobic oxidation methodologies as a response to the necessity to reduce the environmental impact of chemical synthesis and manufacture. Green and sustainable chemical processes rely not only on effective chemistry but also on the implementation of reactor technologies that enhance reaction performance and overall safety. Continuous flow reactors have facilitated safer and more efficient utilization of O2, whilst enabling protocols to be scalable. In this article, we discuss recent advancements in the utilization of continuous processing for aerobic oxidations. The translation of aerobic oxidation from batch protocols to continuous flow processes, including process intensification (high T/p), is examined. The use of “synthetic air”, typically consisting of less than 10% O2 in N2, is compared to pure O2 (100% O2) as an oxidant source in terms of process efficiency and safety. Examples of homogeneous catalysis and heterogeneous (packed bed) catalysis are provided. The application of flow photoreactors for the in situ formation of singlet oxygen (1O2) for use in organic reactions, as well as the implementation of membrane technologies, green solvents and recent reactor solutions for handling O2 are covered.
Highlights
Molecular oxygen (O2) is inexpensive, the most readily available oxidant on Earth, and completely harmless to the environment. O2 is perhaps the greenest reagent available to the organic chemist [1]
The aerobic oxidation within a vortex fluidic device (VFD) configuration performed significantly better compared to in batch where only 5% conversion was observed after 1 h reaction time
Liquid phase aerobic oxidation reactions offer a valuable alternative to classical oxidation methods using stoichiometric quantities of toxic inorganic oxidants
Summary
Molecular oxygen (O2) is inexpensive, the most readily available oxidant on Earth, and completely harmless to the environment. O2 is perhaps the greenest reagent available to the organic chemist [1]. The bulk chemicals sector deals with low value, high volume products and the corresponding production plants are generally designed and engineered as dedicated continuous processes, whereas fine chemicals and the pharmaceutical sec‐ tor have historically favored the use of multipurpose batch reactors for the manufac‐ ture of high value, low volume products [7]. Aerobic oxidation reactions are typically highly exothermic, meaning the heat generated needs to be efficiently removed. These challenges, and the fact that the reaction utilizes potentially flamma‐ ble O2 under certain conditions, increase the perceived scale-up risk, which has rendered the use of O2 virtually unacceptable for pharmaceutical and fine chemical synthesis. The advantages and challenges associated with the utilization of continuous processing for liquid phase aerobic oxi‐ dations are highlighted throughout
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
