Publications associées à Halogénation radicalaire

Reactivity of Bromine Radical with Dissolved Organic Matter Moieties and Monochloramine: Effect on Bromate Formation during Ozonation

Bromine radical (Br center dot) has been hypothesized to be a key intermediate of bromate formation during ozonation. Once formed, Br center dot further reacts with ozone to eventually form bromate. However, this reaction competes with the reaction of Br c ...

AMER CHEMICAL SOC2023

Chlorination of amides: Kinetics and mechanisms of formation of N-chloramides and their reactions with phenolic compounds

Urs von Gunten, Tianqi Zhang

Amides are common constituents in natural organic matter and synthetic chemicals. In this study, we investi-gated kinetics and mechanisms of the reactions of chlorine with seven amides, including acetamide, N-meth-ylformamide, N-methylacetamide, benzamide, ...

2023

Diverting the 5-exo-Trig Oxypalladation to Formally 6-endo-Trig Fluorocycloetherification Product through 1,2-O/Pd(IV) Dyotropic Rearrangement

Qian Wang, Jieping Zhu, Jing Gong

Pd-catalyzed cyclizative functionalization of γ-hydroxyalkenes affords tetrahydrofuran derivatives via a key 5-exo-trig oxypalladation step. Herein, we report a palladium(II)-catalyzed, Selectfluor-mediated formal 6-endo-trig fluorocycloetherification of γ ...

2023

Detecting the metabolism of individual yeast mutant strain cells when aged, stressed or treated with antioxidants with diamond magnetometry

Mayeul Sylvain Chipaux

Free radicals play a key role in the ageing process. However, free radicals are small, reactive and short lived and thus challenging to measure. We utilize a new technique called diamond magnetometry for this pur-pose. We make use of nitrogen vacancy cente ...

ELSEVIER SCI LTD2023

Probing Water Dissociation and Oxygen Replacement on Partially Oxygen-Covered Cu(111) by Reflection Absorption Infrared Spectroscopy

Rainer Beck, Mateusz Suchodol, Harmina Vejayan

The presence of chemisorbed oxygen on the Cu(111) surface is known to strongly reduce the activation barrier for water dissociation as compared to bare Cu(111). Here, we present direct experimental evidence for the hydrogen abstraction mechanism responsibl ...

2023

Widespread detection of chlorine oxyacids in the Arctic atmosphere

Julia Schmale, Ivo Fabio Beck, Hélène Paule Angot

Observations are reported of HClO3 and HClO4 in the atmosphere and their widespread occurrence over the pan-Arctic during spring, providing further insights into atmospheric chlorine cycling in the polar environment. ...

Nature Portfolio2023

Chlorination of arenes via the degradation of toxic chlorophenols

Paul Joseph Dyson, Mingyang Liu, Xuemei Yang

Aryl chlorides are among the most versatile synthetic precursors, and yet inexpensive and benign chlorination techniques to produce them are underdeveloped. We propose a process to generate aryl chlorides by chloro-group transfer from chlorophenol pollutan ...

2022

Construction of Fe3O4 bridged Pt/g-C3N4 heterostructure with enhanced solar to fuel conversion

Michael Graetzel, Shaik Mohammed Zakeeruddin

In this study, we report the effects of co-catalysts of Pt nanoparticles and Fe3O4 clusters on photocatalytic behaviors of g-C3N4 (CN) and the use of the resulting photocatalyst for CO2 photoreduction to solar fuels in a flow reactor operated at room-tempe ...

ELSEVIER2022

Isolation, Characterisation and Reactivity of N-Heterocyclic Diazoolefins

Paul Varava

Examples for applications of nitrous oxide in organic synthesis remain rare up until today. First mayor contributions of our group were published in 2012, when nitrous oxide was successfully captured by N-heterocyclic carbenes. Subsequent studies investiga ...

EPFL2022

Nanodiamond Relaxometry-Based Detection of Free-Radical Species When Produced in Chemical Reactions in Biologically Relevant Conditions

Mayeul Sylvain Chipaux

Diamond magnetometry is a quantum sensing method involving detection of magnetic resonances with nanoscale resolution. For instance, T1 relaxation measurements, inspired by equivalent concepts in magnetic resonance imaging (MRI), provide a signal that is e ...

AMER CHEMICAL SOC2020

Generation of hydroxyl radical during chlorination of hydroxyphenols and natural organic matter extracts

Urs von Gunten, Eva Maria Rodriguez Franco

The generation of hydroxyl radicals ((OH)-O-center dot) during the chlorination of air saturated solutions of different hydroxyphenols (hydroquinone, resorcinol, catechol, gallic and tannic acids) at pH 7 has been determined by the formation of phenol (in ...

2020

A wearable electrochemical sensing system for non-invasive monitoring of lithium drug in bipolar disorder

Giovanni De Micheli, Sandro Carrara, Irene Taurino, Francesca Criscuolo

Lithium represents the main drug for the treatment of Bipolar Disorder (BD) as it acts as a mood stabilizer. However, because of its narrow therapeutic window, psychiatric patients are obliged to frequent tests in hospital to control their lithium blood co ...

2021

Indirect CO2 Methanation: Hydrogenolysis of Cyclic Carbonates Catalyzed by Ru-Modified Zeolite Produces Methane and Diols

Paul Joseph Dyson, Felix Daniel Bobbink, Antoine Philippe Van Muyden, Wei-Tse Lee, Zhangjun Huang

We report a ruthenium‐modified zeolite which efficiently transforms propylene carbonate to propylene glycol and methane, under solvent‐free conditions. The catalyst achieved high product selectivity and no significant ageing effect was observed after multi ...

Wiley-VCH Verlag GmbH2019

In Situ Formation of Free Chlorine During ClO2 Treatment: Implications on the Formation of Disinfection Byproducts

Urs von Gunten

Chlorine dioxide (ClO2) is commonly used as an alternative disinfectant to chlorine in drinking water treatment because it produces limited concentrations of halogenated organic disinfection byproducts. During drinking water treatment, the primary ClO2 byp ...

AMER CHEMICAL SOC2018

Impact of Combined Chlorination and Chloramination Conditions on N-Nitrosodimethylamine Formation

Urs von Gunten

Bench-scale chloramination under uniform formation conditions was used to examine N-nitrosodimethylamine (NDMA) formation in settled and (bio)filtered drinking water and treated wastewater. In this study, water temperature, pH, postchloramination time, and ...

WILEY2018

Room temperature C(sp(2))-H oxidative chlorination via photoredox catalysis

Xile Hu, Lei Zhang

Photoredox catalysis has been developed to achieve oxidative C-H chlorination of aromatic compounds using NaCl as the chlorine source and Na2S2O8 as the oxidant. The reactions occur at room temperature and exhibit exclusive selectivity for C(sp(2))-H bonds ...

Royal Soc Chemistry2017

Electrochemical Detection of Free Chlorine at Inkjet Printed Silver Electrodes

Hubert Girault, Andreas Stephan Lesch, Fernando Cortes Salazar, Véronique Amstutz, Hongyan Bi, Milica Jovic

A low-cost, reliable and sensitive electrochemical method for free chlorine analysis in water using inkjet printed silver electrodes is presented. Free chlorine detection was based on linear sweep voltammetry (LSV) analysis of AgCl/Ag2O films formed over a ...

Elsevier Science Sa2015

Antioxidant Promotion of Tyrosine Nitration in the Presence of Copper(II)

Hubert Girault, Liang Qiao

Copper(II) is known to catalyze the generation of reactive nitrogen species in the presence of hydrogen peroxide, nitrite or nitric oxide, leading to tyrosine nitration, a biomarker for free radical species associated diseases. Here, we find that biologica ...

Royal Society of Chemistry2013

Reactivity of BrCl, Br2, BrOCl, Br2O and HOBr toward dimethenamid in solutions of bromide + aqueous free chlorine

Jeremy Samuel Arey, Peter Rudolf Tentscher

HOBr, formed via oxidation of bromide by free available chlorine (FAC), is frequently assumed to be the sole species responsible for generating brominated disinfection byproducts (DBPs). Our studies reveal that BrCl, Br-2, BrOCl, and Br2O can also serve as ...

Amer Chemical Soc2013

Significant decrease of THMs generated during chlorination of river water by previous photo-Fenton treatment at near neutral pH

César Pulgarin

An important issue in chlorine drinking water disinfection is the generation from natural organic matter (NOM) of disinfection by-products (DBPs), especially trihalomethanes (THMs). The THMs generation can be limited by reducing the levels of NOM prior to ...

2012