radical species
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2022 ◽  
Vol 65 ◽  
pp. 433-438
Author(s):  
Dongyoon Shin ◽  
Sabita Bhandari ◽  
Marc F. Tesch ◽  
Shannon A. Bonke ◽  
Frédéric Jaouen ◽  
...  

Processes ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 124
Author(s):  
Xiao Ma ◽  
Zhenjun Wang

Ciprofloxacin (CIP), as a common antibiotic used in human clinical and livestock farming, is discharged into natural water bodies and its concentration has increased in the last years. Its stable chemical structure is difficult to remove by conventional techniques. Residual ciprofloxacin in the environment has become an emerging micropollutant that promotes the generation of resistance genes of bacteria and endangers ecosystem balance and human health. Removal of ciprofloxacin from water by the system of ultrasound/electric field/sodium persulfate (US/E/PS) was investigated. Firstly, CIP degradation affects by different oxidation methods, such as ultrasonic oxidation, electro-oxidation, and persulfate oxidation, and their four combined oxidation methods (ultrasound-activated persulfate oxidation, electro-activated persulfate oxidation, ultrasound-enhanced electro-oxidation, and ultrasound-enhanced electro-activated persulfate oxidation), on the target contaminants were compared. Secondly, the influences of parameters on the CIP degradation by an ultrasound-enhanced electro-activation-persulfate reaction system were investigated. Thirdly, the possible free radical species in the ultrasound-enhanced electro-activation-sulfate reaction system were identified and the dominant free radical species in the system were analyzed. Finally, the samples of CIP in the US/E/PS system were tested by liquid mass spectrometry, and the possible intermediate products and degradation path were speculated. The results indicate that the US/E/PS system is of great potential application value in the removal of organic pollution and environmental purification.


Author(s):  
Yusuke Makino ◽  
Megumi Ueno ◽  
Yoshimi Shoji ◽  
Minako Nyui ◽  
Ikuo Nakanishi ◽  
...  

Author(s):  
Maja Milojević-Rakić ◽  
Daliborka Popadić ◽  
Aleksandra Janosevic ◽  
Anka Jevremović ◽  
Bojana Nedić Vasiljević ◽  
...  

Ecotoxicity caused by neonicotinoid pesticides is largely due to oxidative stress on non-target species. Due to the fact that reactive radical species reach the environment, materials intended for pesticide removal...


2021 ◽  
Author(s):  
Abhishek Dewanji ◽  
Leendert van Dalsen ◽  
James Rossi-Ashton ◽  
Eloise Gasson ◽  
Giacomo Crisenza ◽  
...  

The photoactivation of electron donor-acceptor (EDA) complexes has emerged as a sustainable, selective and versa-tile strategy for the generation of radical species. However, when it comes to aryl radical formation, this strategy remains hamstrung by the electronic properties of the aromatic radical precursors and electron-deficient aryl halide acceptors are required. This has prevented the implementation of a general synthetic platform for aryl radical for-mation. Our study introduces triarylsulfonium salts as acceptors in photoactive EDA-complexes, used in combina-tion with catalytic amounts of newly-designed amine donors. The sulfonium salt label renders inconsequential the electronic features of the aryl radical precursor and, more importantly, it is installed regioselectively in native aro-matic compounds by C–H sulfenylation. Using this general, site-selective aromatic C–H functionalization approach, we have developed metal-free protocols for the alkylation and cyanation of arenes, and showcased their application in both the synthesis and the late-stage modification of pharmaceuticals and agrochemicals.


Author(s):  
Soraya Boukhedoua ◽  
Razika Zouaghi ◽  
Oualida Nour El Houda Kaabeche

Abstract In the present work, a comparative study of the photooxidation of an aqueous solution of Methyl Orange (MeO) has been realized using H2O2 and IO3 −, BrO3 −, ClO3 −, ClO4 −, BO3 − ions in the presence of UV low pressure mercury lamp (UV-C light at λ max = 254 nm). The initial concentration of MeO in all experiments was 6 × 10−5 mol L−1. The degradation rate of MeO follows pseudo-first-order kinetics in all UV/Oxidant systems. The highest degradation rate of MeO was in the BrO3 −/UV254nm system. Different systems were compared for an oxidant concentration of 10−2 mol L−1 and the obtained results showed that decolorization followed the decreasing order: BrO 3 − /UV 254 nm  > IO 3 − /UV 254 nm  > H 2 O 2 /UV 254 nm  > BO 3 − /UV 254 nm  > ClO 3 − /UV 254 nm  = ClO 4 − /UV 254 nm  = UV 254 nm . The optimization of oxidants concentration for each process was determined (10−2 mol L−1 for IO3 − which gives almost the same k app for 5 × 10−3, 10−2 mol L−1 for BO3 − and 5 × 10−2 mol L−1 for H2O2). No degradation of MeO in presence of ClO3 − and ClO4 − because these ions do not absorb at 254 nm, therefore they do not generate radical species which degrade organic pollutants. The mineralization was also studied where it was reached 97% after 5 h of irradiation for both H2O2/UV254 nm and BO3 −/UV254 nm systems.


Molecules ◽  
2021 ◽  
Vol 26 (22) ◽  
pp. 6843
Author(s):  
Xiang-Kui He ◽  
Juan Lu ◽  
Hai-Bing Ye ◽  
Lei Li ◽  
Jun Xuan

An acyl radical generation and functionalization strategy through direct photoexcitation of benzothiazolines has been developed. The formed acyl radical species can either be trapped by quinoxalin-2-ones to realize their C(3)-H functionalization or trigger a cascade radical cyclization with isonitriles to synthesise biologically important phenanthridines. The synthetic value of this protocol can be further illustrated by the modification of quinoxalin-2-ones, containing important natural products and drug-based complex molecules.


Synthesis ◽  
2021 ◽  
Author(s):  
Yong-liang Su ◽  
Michael P. Doyle

α-Aminoalkyl radicals are easily accessible through multiple pathways from various precursors. Apart from their utilization as N-containing building blocks, they have recently been used as halogen atom abstraction reagents or single-electron reductants to transform organic halides or sulfonium salts to their corresponding highly reactive radical species. Benefiting from the richness of various halides and the diverse reactivity of radical intermediates, new transformations of halides and sulfonium salts have been developed. This short review summarizes this emerging chemistry that uses α-amino radicals as the reaction activators.


2021 ◽  
pp. 133493
Author(s):  
Zexiu An ◽  
Mingxue Li ◽  
Yanru Huo ◽  
Jinchan Jiang ◽  
Yuxin Zhou ◽  
...  

Polymers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 3517
Author(s):  
Horst Berneth ◽  
Friedrich Karl Bruder ◽  
Thomas Fäcke ◽  
Sven Hansen ◽  
Koichi Kawamura ◽  
...  

Versatile substituted electron-deficient trichloromethylarenes can easily be synthesized and combined with a Safranine O/triarylalkylborate salt to form a highly efficient three-component photo-initiation system that starts free radical polymerization to finally form holographic gratings with a single-pulsed laser. The mechanism of this photo-initiation most likely relies on an electron transfer from the borate salt into the semi-occupied HOMO of the excited dye molecule Safranine O, which after fragmentation generates an initiating alkyl radical and longer-lived dye radical species. This dye radical is most probably oxidized by the newly introduced trichloromethylarene derivative as an electron acceptor. The two generated radicals from one absorbed photon initiate the photopolymerization and form index gratings in a suitable holographic recording material. This process is purely photonic and does not require further non-photonic post treatments.


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