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Chlorine reactivity

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https://www.readbyqxmd.com/read/27918047/oxidations-of-chromene-annulated-chlorins
#1
Nisansala Hewage, Matthias Zeller, Christian Brückner
A chromene-annulated chlorin is a meso-pentafluorophenyl-2,3-dihydroxychlorin in which one of the hydroxy groups is linked to the ortho-position of a flanking meso-aryl group, thereby forming an annulated chromene moiety; the second hydroxy group is unprotected. This report illustrates the oxidation chemistry of the chromene-annulated chlorin under a number of different oxidation conditions. In some reactions, chromene annulation is retained and the non-protected alcohol is oxidized, generating chlorin-like chromophores carrying pyrroline β-carbons in oxidation states between those found in typical porphyrins and chlorins...
December 5, 2016: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/27914346/tuning-particle-geometry-of-chemically-anisotropic-dumbbell-shaped-colloids
#2
Bas G P van Ravensteijn, Willem K Kegel
Chemically anisotropic dumbbell-shaped colloids are prepared starting from cross-linked polymer seed particles coated with a chlorinated outer layer. These chlorinated seeds are swollen with monomer. Subsequently, a liquid protrusion is formed on the surface of the seed particle by phase separation between the monomer and the swollen polymer network. Solidification of these liquid lobes by polymerization leads to the desired dumbbell-shaped colloids. The chlorine groups remain confined on the seed lobe of the particles, ensuring chemical anisotropy of the resulting particles...
November 15, 2016: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/27894785/simulating-stable-carbon-and-chlorine-isotope-ratios-in-dissolved-chlorinated-groundwater-pollutants-with-biochlor-iso
#3
Patrick Höhener
BIOCHLOR is a well-known simple tool for evaluating the transport of dissolved chlorinated solvents in groundwater, ideal for rapid screening and teaching. This work extends the BIOCHLOR model for the calculation of stable isotope ratios of carbon and chlorine isotopes in chloroethenes. An exact solution for the three-dimensional reactive transport of a chain of degrading compounds including sorption is provided in a spreadsheet and applied for modeling the transport of individual isotopes (12)C, (13)C, (35)Cl, (37)Cl from a constant source...
November 21, 2016: Journal of Contaminant Hydrology
https://www.readbyqxmd.com/read/27873198/fabrication-of-bio-function-preserved-saccharide-microarray-chips-with-cyanuric-chloride-as-a-rotatable-linker
#4
Yi Chen, Chanjuan Liu, Xiao Wang
Microarray-based saccharide chips possess an inherent property of high throughput but remain hard to use in practice due mainly to their fabrication problems, which have led to many strategies proposed but nearly none can immobilize small saccharides without losing their bio-affinity. Herein introduced is an easy strategy able to directly immobilize all intact saccharides on solid surface with excellent preservation of their molecular recognition ability. The core idea is to anchor a saccharide molecule on a universally rotatable molecular frame to free its spatial adjustment during molecular recognition process...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/27797001/sodium-chlorate-a-herbicide-and-major-water-disinfectant-byproduct-generates-reactive-oxygen-species-and-induces-oxidative-damage-in-human-erythrocytes
#5
Shaikh Nisar Ali, Mir Kaisar Ahmad, Riaz Mahmood
Sodium chlorate (NaClO3) is a widely used non-selective herbicide. It is also generated as a byproduct during disinfection of drinking water by chlorine dioxide. In the present work, the effects of NaClO3 on human erythrocytes were studied under in vitro conditions. Incubation of erythrocytes with different concentrations of NaClO3 at 37 °C for 90 min resulted in significant hemolysis. Cell lysates were prepared from NaClO3-treated and untreated (control) erythrocytes and assayed for various biochemical parameters...
October 31, 2016: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/27744694/development-of-a-model-immunoassay-utilizing-monoclonal-antibodies-of-different-specificities-for-quantitative-determination-of-dieldrin-and-heptachlors-in-their-mixtures
#6
Chiwa Kataoka, Masumi Nihei, Masaomi Nimata, Kazuyuki Sawadaishi
The presence of dieldrin and heptachlor residues in cucurbitaceous crops at concentrations exceeding the limits set by the Japanese Food Sanitation Law constitutes a serious problem. To prevent accumulation of these residues in cucurbitaceous crops, development of high-throughput analysis methods for the detection of contaminants in the soil before cultivation is required. In this study, we aimed to develop a model immunoassay using new monoclonal antibodies (MAbs) to quantitatively determine dieldrin and heptachlor contents in their mixtures...
October 17, 2016: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/27722305/reactivity-of-electrophilic-chlorine-atoms-due-to-%C3%AF-holes-a-mechanistic-assessment-of-the-chemical-reduction-of-a-trichloromethyl-group-by-sulfur-nucleophiles
#7
Guillermo Caballero-García, Moisés Romero-Ortega, Joaquín Barroso-Flores
σ-Holes are shown to promote the electrophilic behavior of chlorine atoms in a trichloromethyl group when bound to an electron-withdrawing moiety. A halogen bond-type non-covalent interaction between a chlorine atom and a negatively charged sulfur atom takes place, causing the abstraction of such a chlorine atom while leaving a carbanion, subsequently driving the chemical reduction of the trichloromethyl group to a sulfide in a stepwise process. The mechanism for the model reaction of trichloromethyl pyrimidine 1 with thiophenolate and thiophenol to yield phenylsulfide 4 was followed through (1)H-NMR and studied using DFT transition state calculations, and the energy profile for this transformation is fully discussed...
October 5, 2016: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/27711891/transformation-of-mackinawite-to-greigite-by-trichloroethylene-and-tetrachloroethylene
#8
Ying Lan, Andrew S Elwood Madden, Elizabeth C Butler
Trichloroethylene (TCE) and tetrachloroethylene (PCE) are common ground water contaminants susceptible to reductive dechlorination by FeS (mackinawite) in anaerobic environments. The objective of this study was to characterize the mineral-associated products that form when mackinawite reacts with TCE and PCE. The dissolved products of the reaction included Cl(-) and Fe(2+), and trace amounts of cis 1,2-dichloroethylene (for TCE) and TCE (for PCE). Selected area electron diffraction (SAED) analysis identified greigite as a mackinawite oxidation product formed after reaction between TCE or PCE and FeS over seven weeks...
October 12, 2016: Environmental Science. Processes & Impacts
https://www.readbyqxmd.com/read/27711775/dehalogenation-of-chloroalkanes-by-nickel-i-porphyrin-derivatives-a-computational-study
#9
L Szatkowski, M B Hall
The nickel(i) octaethylisobacteriochlorin anion ([OEiBCh-Ni((I))](-)) is commonly used as a synthetic model of cofactor F430 from Methyl-Coenzyme M Reductase. In this regard, experimental studies show that [OEiBCh-Ni((I))](-) can catalyze dehalogenation of aliphatic halides in DMF solution by a highly efficient SN2 reaction. To better understand this process, we constructed theoretical models of the dehalogenation of chloromethane by a simple nickel(i) isobacteriochlorin anion and compared its reactivity with that of similar Ni((I)) complexes with other porphyrin-derived ligands: porphyrin, chlorin, bactreriochlorin, hexahydroporphyrin and octahydroporphyrin...
September 28, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/27708235/a-next-generation-bifunctional-photosensitizer-with-improved-water-solubility-for-photodynamic-therapy-and-diagnosis
#10
Hirotada Nishie, Hiromi Kataoka, Shigenobu Yano, Jun-Ichi Kikuchi, Noriyuki Hayashi, Atsushi Narumi, Akihiro Nomoto, Eiji Kubota, Takashi Joh
Photodynamic therapy (PDT) exploits light interactions and photosensitizers to induce cytotoxic reactive oxygen species. Photodynamic diagnosis (PDD) uses the phenomenon of photosensitizer emitting fluorescence to distinguish some tumors from normal tissue. The standard photosensitizer used for PDD is 5-aminolevulinic acid (5-ALA), although it is not entirely satisfactory. We previously reported glucose-conjugated chlorin (G-chlorin) as a more effective photosensitizer than another widely used photosensitizer, talaporfin sodium (TS); however, G-chlorin is hydrophobic...
September 30, 2016: Oncotarget
https://www.readbyqxmd.com/read/27678495/mechanically-robust-and-transparent-n-halamine-grafted-pva-co-pe-films-with-renewable-antimicrobial-activity
#11
Yang Si, Andrea Cossu, Nitin Nitin, Yue Ma, Cunyi Zhao, Bor-Sen Chiou, Trung Cao, Dong Wang, Gang Sun
Antimicrobial polymeric films that are both mechanically robust and function renewable would have broad technological implications for areas ranging from medical safety and bioengineering to foods industry; however, creating such materials has proven extremely challenging. Here, a novel strategy is reported to create high-strength N-halamine incorporated poly(vinyl alcohol-co-ethylene) films (HAF films) with renewable antimicrobial activity by combining melt radical graft polymerization and reactive extrusion technique...
September 28, 2016: Macromolecular Bioscience
https://www.readbyqxmd.com/read/27677119/a-comparative-study-of-microcystin-lr-degradation-by-electrogenerated-oxidants-at-bdd-and-mmo-anodes
#12
Shiqing Zhou, Lingjun Bu, Yanghai Yu, Xu Zou, Yansen Zhang
This study investigated the electrochemical degradation of microcystin-LR (MC-LR) using boron-doped diamond (BDD) anode and mixed metal oxides (MMO, IrO2Ta2O5/Ti) anode in different medium. In-situ electrogenerated oxidants including hydroxyl radical, active chlorine, and persulfate were confirmed in phosphate, chloride, and sulfate medium, respectively. Different from MMO anode, hydroxyl radical was observed to play a significant role in chlorine generation at BDD anode in chloride medium. Besides, BDD anode could activate sulfate electrochemically due to its high oxygen evolution potential, and MC-LR degradation rate increased with the decrease of solution pH...
December 2016: Chemosphere
https://www.readbyqxmd.com/read/27664542/effect-of-chloride-on-the-formation-of-volatile-disinfection-byproducts-in-chlorinated-swimming-pools
#13
Yue E, Hui Bai, Lushi Lian, Jing Li, Ernest R Blatchley
Chloride can accumulate in chlorinated swimming pool water. Although substantial efforts have been made to examine the effects of halide ions on the formation of volatile disinfection byproducts (DBPs), most have focused on bromide. The effects of chloride ion concentration on the formation of volatile DBPs in swimming pools remain largely unstudied. In this study, chlorination of typical precursors and body fluid analogue (BFA) were investigated with variable chloride concentration and pH. The formation of three volatile DBPs (NCl3, CHCl3 and CNCHCl2) was observed to be linearly correlated with chloride concentration, both in bench experiments and in actual swimming pool water samples...
November 15, 2016: Water Research
https://www.readbyqxmd.com/read/27643481/comparison-of-n-nitrosodimethylamine-formation-mechanisms-from-dimethylamine-during-chloramination-and-ozonation-a-computational-study
#14
Yong Dong Liu, Rugang Zhong
N-nitrosodimethylamine (NDMA) as a disinfection by-product has recently become the focus of considerable research interest due to its unusually high carcinogenicity. In this study, the formation mechanisms of NDMA from dimethylamine (DMA) during chloramination and ozonation were investigated by using the quantum chemical G4 method. The reactivity of haloamines and hydroxylamine reacting with DMA was found in the order: NHCl2∼NHBrCl (Br-leaving)>NHBr2>NH2Cl∼NH2Br>NH2OH. This offers a theoretical support for the experimentally proposed mechanism that dimethylamine reacts with NHCl2 rather than NH2Cl to form chlorinated unsymmetrical dimethylhydrazine intermediate and the existence of bromochloramine in the presence of bromide during chloramination, and explains the observation that NDMA yield during ozonation is much lower than that during chloramination...
September 12, 2016: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/27640160/theoretical-investigation-of-loratadine-reactivity-in-order-to-understand-its-degradation-properties-dft-and-md-study
#15
Stevan Armaković, Sanja J Armaković, Biljana F Abramović
Antihistamines are frequently used pharmaceuticals that treat the symptoms of allergic reactions. Loratadine (LOR) is an active component of the second generation of selective antihistaminic pharmaceutical usually known as Claritin. Frequent usage of this type of pharmaceuticals imposes the need for understanding their fundamental reactive properties. In this study we have theoretically investigated reactive properties of LOR using both density functional theory (DFT) calculations and molecular dynamics (MD) simulations...
October 2016: Journal of Molecular Modeling
https://www.readbyqxmd.com/read/27639466/the-rate-determining-step-in-a-low-temperature-pcdd-f-formation-from-oxidative-breakdown-of-native-carbon-in-mswi-fly-ash
#16
Elena Collina, Marina Lasagni, Elsa Piccinelli, Manuela Nadia Anzano, Demetrio Pitea
We developed a phenomenological approach to explain the kinetic experimental data of PCDD/F formation/destruction based on a reaction mechanism model at the congener group level. In the present work, we investigated the formation and destruction of PCDD/F on fly ash as a function of time at 280 °C, chlorine mass balance, evolution of the total equivalent toxicity and kinetic modelling. We determined that the volatilization process is negligible and that the reactive processes at short reaction times only become important above 300 °C...
December 2016: Chemosphere
https://www.readbyqxmd.com/read/27611888/levels-of-inflammation-and-oxidative-stress-and-a-role-for-taurine-in-dystropathology-of-the-golden-retriever-muscular-dystrophy-dog-model-for-duchenne-muscular-dystrophy
#17
Jessica R Terrill, Marisa N Duong, Rufus Turner, Caroline Le Guiner, Amber Boyatzis, Anthony J Kettle, Miranda D Grounds, Peter G Arthur
Duchenne Muscular Dystrophy (DMD) is a fatal skeletal muscle wasting disease presenting with excessive myofibre necrosis and increased inflammation and oxidative stress. In the mdx mouse model of DMD, homeostasis of the amino acid taurine is altered, and taurine administration drastically decreases muscle necrosis, dystropathology, inflammation and protein thiol oxidation. Since the severe pathology of the Golden Retriever Muscular Dystrophy (GRMD) dog model more closely resembles the human DMD condition, we aimed to assess the generation of oxidants by inflammatory cells and taurine metabolism in this species...
August 30, 2016: Redox Biology
https://www.readbyqxmd.com/read/27607930/formation-of-iodo-trihalomethanes-iodo-acetic-acids-and-iodo-acetamides-during-chloramination-of-iodide-containing-waters-factors-influencing-formation-and-reaction-pathways
#18
Shaogang Liu, Zhenlin Li, Huiyu Dong, Bernard A Goodman, Zhimin Qiang
This study investigated systematically the factors influencing the formation of iodinated disinfection by-products (I-DBPs) during chloramination of I(-)-containing waters, including reaction time, NH2Cl dose, I(-) concentration, pH, natural organic matter (NOM) concentration, Br(-)/I(-) molar ratio, and water matrix. Among the I-DBPs detected, iodoform (CHI3), iodoacetic acid (IAA), diiodoacetic acid (DIAA), triiodoacetic acid (TIAA), and diiodoacetamide (DIAcAm) were the major species produced from reactions between reactive iodine species (HOI/I2) and NOM...
August 30, 2016: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/27598293/rapid-hydrogen-and-oxygen-atom-transfer-by-a-high-valent-nickel-oxygen-species
#19
Teresa Corona, Apparao Draksharapu, Sandeep K Padamati, Ilaria Gamba, Vlad Martin-Diaconescu, Ferran Acuña-Parés, Wesley R Browne, Anna Company
Terminal high-valent metal-oxygen species are key reaction intermediates in the catalytic cycle of both enzymes (e.g., oxygenases) and synthetic oxidation catalysts. While tremendous efforts have been directed toward the characterization of the biologically relevant terminal manganese-oxygen and iron-oxygen species, the corresponding analogues based on late-transition metals such as cobalt, nickel or copper are relatively scarce. This scarcity is in part related to the "Oxo Wall" concept, which predicts that late transition metals cannot support a terminal oxido ligand in a tetragonal environment...
October 5, 2016: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/27589240/impact-of-prechlorination-on-organophosphorus-pesticides-during-drinking-water-treatment-removal-and-transformation-to-toxic-oxon-byproducts
#20
Wei Li, Ruiqing Wu, Jinming Duan, Christopher P Saint, John van Leeuwen
Prechlorination is commonly used to minimize operational problems associated with biological growth as well as taste and odor control during drinking water treatment. However, prechlorination can also oxidise micropollutants into intermediate byproducts. This could impose profound effects on the safety of the finished water if the transformed byproducts are more toxic and less removable. This study investigated the effect of prechlorination on decomposition and subsequent removal of the four organophosphorus pesticides (OPPs): chlorpyrifos, diazinon, malathion and tolclofos-methyl using a simulated conventional water treatment process of powdered activated carbon assisted coagulation-sedimentation-filtration (PAC-CSF) and postchlorination...
November 15, 2016: Water Research
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