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Updated: Jun 21, 2026
![[(DPEPhos)(bcp)Cu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F59739.jpg&w=3840&q=50)
[(DPEPhos)(bcp)Cu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst
Published on: May 21, 2019
Photolytic removal and mineralisation of 2-halogenated pyridines
David R Stapleton1, Ioannis K Konstantinou, Dimitra G Hela
1Chemical Engineering, IPSE, School of Process Environmental and Materials Engineering, University of Leeds, Leeds LS2 9JT, UK.
Abstract:
The photolytic destruction and mineralisation of 2-halogenated pyridines (2-HalPYs) was studied in a range of conditions by means of ultraviolet irradiation at 254 nm. In all cases pseudo-first order kinetics satisfactorily describe the degradation process. Key decomposition products were identified and primary reaction pathways are proposed. 2-HalPYs were rapidly dehalogenated with a subsequent sharp pH drop. Complete Total Organic Carbon (TOC) removal was achieved. Their photolytic removal rate is not affected by pH or aeration. The fastest TOC removal was observed in 2-fluoropyridine (2-FPY) photolysis. 2-Hydroxypyridine (2-HPY) was identified as the primary intermediate formed by destruction of 2-chloropyridine (2-CPY), 2-bromopyridine (2-BPY) and 2-iodopyridine (2-IPY). 2-HPY is further destructed to form Dewar pyridinone. 2-FPY only marginally reacted to form 2-HPY. Instead, its major intermediate product is Dewar pyridinone. 2-IPY results in a, most likely aliphatic, photostable product, the production of which appears to increase at low pH and high 2-HPY concentration.
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