Continuous photo-oxidation in a vortex reactor: efficient operations using air drawn from the laboratory

Lee, Darren S. and Amara, Zacharias and Clark, Charlotte A. and Xu, Zeyuan and Kakimpa, Bruce and Morvan, Herve and Pickering, S.J. and Poliakoff, Martyn and George, Michael W. (2017) Continuous photo-oxidation in a vortex reactor: efficient operations using air drawn from the laboratory. Organic Process Research and Development, 21 (7). pp. 1042-1050. ISSN 1520-586X

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Abstract

We report the construction and use of a vortex reactor which uses a rapidly rotating cylinder to generate Taylor vortices for continuous flow thermal and photochemical reactions. The reactor is designed to operate under conditions required for vortex generation. The flow pattern of the vortices has been represented using computational fluid dynamics, and the presence of the vortices can be easily visualized by observing streams of bubbles within the reactor. This approach presents certain advantages for reactions with added gases. For reactions with oxygen, the reactor offers an alternative to traditional setups as it efficiently draws in air from the lab without the need specifically to pressurize with oxygen. The rapid mixing generated by the vortices enables rapid mass transfer between the gas and the liquid phases allowing for a high efficiency dissolution of gases. The reactor has been applied to several photochemical reactions involving singlet oxygen (1O2) including the photo-oxidations of α-terpinene and furfuryl alcohol and the photodeborylation of phenyl boronic acid. The rotation speed of the cylinder proved to be key for reaction efficiency, and in the operation we found that the uptake of air was highest at 4000 rpm. The reactor has also been successfully applied to the synthesis of artemisinin, a potent antimalarial compound; and this three-step synthesis involving a Schenk-ene reaction with 1O2, Hock cleavage with H+, and an oxidative cyclization cascade with triplet oxygen (3O2), from dihydroartemisinic acid was carried out as a single process in the vortex reactor.

Item Type: Article
Schools/Departments: University of Nottingham, UK > Faculty of Engineering > Department of Mechanical, Materials and Manufacturing Engineering
Identification Number: 10.1021/acs.oprd.7b00153
Depositing User: Morvan, Herve
Date Deposited: 07 Aug 2017 15:02
Last Modified: 07 Aug 2017 15:02
URI: http://eprints.nottingham.ac.uk/id/eprint/44732

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