Oxygen sensors for flow reactors – measuring dissolved oxygen in organic solvents. Issue 12 (3rd September 2019)

• Record Type: Journal Article
• Authors: Sulzer, Philipp; Lebl, René; Kappe, C. Oliver; Mayr, Torsten
• Is Part Of: Reaction chemistry & engineering. Volume 4:Issue 12(2019)
• Page Start: 2081
• Page End: 2087
• Publication Date: 2019-09-03
• Subjects: Reaction mechanisms (Chemistry) -- Periodicals; Chemical engineering -- Periodicals; Chemical engineering; Reaction mechanisms (Chemistry); Periodicals; 547.705
• DOI: 10.1039/c9re00253g
• Languages: English
• ISSNs: 2058-9883

Abstract

Abstract : We are demonstrating a solvent resistant optical sensor for measuring dissolved oxygen in pressurized micro flow reactors. Abstract : In an effort to push the boundaries of optical oxygen sensors, this contribution shows the development of a measurement system for high O2 content in organic solvents specifically designed for flow reactors. Presented sensors were prepared by directly melting an oxygen indicator dye into a highly resistant polymer matrix, leading to the ability to measure oxygen contents up to 59 mmol L −1 in tetrahydrofuran, toluene, acetone, dimethylformamide, cyclohexane and methyl tert -butyl ether. Long-term effects to the solvent were investigated by exposing the sensors for 22 hours to the respective solvent at 25 °C. Linearity according to Stern–Volmer was obtained for every single sensor in order to provide a system that can be easily initialized by two-point calibration into continuous flow reactors. To demonstrate the applicability of the sensor under reaction conditions, an oxidation of a Grignard reagent with molecular oxygen was performed in a flow reactor. The sensors were able to show the oxygen decrease during reaction and allowed online reactant quantification.