Hydroxyl radical, sulfate radical and nitrate radical reactivity towards crown ethers in aqueous solutions

2012 ◽  
Vol 81 (5) ◽  
pp. 524-530 ◽  
Author(s):  
L.K. Wan ◽  
J. Peng ◽  
M.Z. Lin ◽  
Y. Muroya ◽  
Y. Katsumura ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Hydroxyl Radical ◽  
Crown Ethers ◽  
Sulfate Radical ◽  
Nitrate Radical ◽  
Radical Reactivity

Reactivity of Oxygen Radicals [HO•, RO•, HOO•, ROO-, and RC(O)O•]

1992 ◽  
Author(s):  
Donald T. Sawyer ◽  
R. J. P. Williams
Keyword(s):  
Oxygen Atom ◽  
Hydroxyl Radical ◽  
Gas Phase ◽  
Oxygen Radicals ◽  
Oxygen Radical ◽  
Superoxide Ion ◽  
Radical Reactivity ◽  
The Family ◽  
Hydrocarbon Substrates

Oxygen radicals are defined as those molecules that contain an oxygen atom with an unpaired, nonbonding electron (e.g., HO·). Although triplet dioxygen (·O2·) and superoxide ion (O2 - ·) come under this definition, their nonradical chemistry dominates their reactivity, which is discussed in Chapters 6 (·O2·) and 7 (O2-·). The hydroxyl radical (HO·) is the most reactive member of the family of oxygen radicals [HO·, RO·, ·O·, HOO·, ROO·, and RC(O)O·], and is the focus of most oxygen radical research. In the gas phase the dramatic example of oxygen radical reactivity with hydrocarbon substrates is combustion, which is initiated by HO· (or RO· or MO·) and propagated by ·O2· and ·O·.

scholarly journals Complex Uranyl Dichromates Templated by Aza-Crowns

Crystals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 462 ◽  
Author(s):  
Oleg Siidra ◽  
Evgeny Nazarchuk ◽  
Dmitry Charkin ◽  
Stepan Kalmykov ◽  
Anastasiya Zadoya
Keyword(s):  
Aqueous Solutions ◽  
Crown Ethers ◽  
Room Temperature ◽  
Organic Molecules ◽  
Negative Charge ◽  
Uranyl Compounds ◽  
One Dimensional ◽  
Chain Complexes ◽  
Aza Crown Ethers

Three new uranyl dichromate compounds templated by aza-crown templates were obtained at room temperature by evaporation from aqueous solutions: (H2diaza-18-crown-6)2[(UO2)2(Cr2O7)4(H2O)2](H2O)3 (1), (H4[15]aneN4)[(UO2)2(CrO4)2(Cr2O7)2(H2O)] (H2O)3.5 (2) and (H4Cyclam)(H4[15]aneN4)2[(UO2)6(CrO4)8(Cr2O7)4](H2O)4 (3). The use of aza-crown templates made it possible to isolate unprecedented and complex one-dimensional units in 2 and 3, whereas the structure of 1 is based on simple uranyl-dichromate chains. It is very likely that the presence of relatively large organic molecules of aza-crown ethers does not allow uranyl chromate chain complexes to condense into the units of higher dimensionality (layers or frameworks). In general, the formation of 1, 2, and 3 is in agreement with the general principles elaborated for organically templated uranyl compounds. The negative charge of the [(UO2)(Cr2O7)2(H2O)]2−, [(UO2)2(CrO4)2(Cr2O7)2(H2O)]4− and [(UO2)3(CrO4)4(Cr2O7)2]6− one-dimensional inorganic motifs is compensated by the protonation of all nitrogen atoms in the molecules of aza-crowns.

scholarly journals Efficient Degradation of Acesulfame by Ozone/Peroxymonosulfate Advanced Oxidation Process

Molecules ◽  
2019 ◽  
Vol 24 (16) ◽  
pp. 2874 ◽  
Author(s):  
Yu Shao ◽  
Zhicheng Pang ◽  
Lili Wang ◽  
Xiaowei Liu
Keyword(s):  
Hydroxyl Radical ◽  
Active Sites ◽  
Emerging Contaminants ◽  
Water Solubility ◽  
Advanced Oxidation Process ◽  
Negative Impact ◽  
Degradation Products ◽  
Electrical Energy ◽  
Sulfate Radical ◽  
Electrical Energy Per Order

Artificial sweeteners (ASWs), a class of emerging contaminants with good water solubility, have attracted much attention recently because of their wide use and negative impact on the aquatic environment and drinking water. Efficient technologies for removing ASWs are in urgent need. This study investigated degradation of typical ASW acesulfame by ozone-activated peroxymonosulfate process (O3/PMS) in prepared and real waters. O3/PMS can degrade >90% acesulfame in prepared water within 15 min at a low dosage of O3 (60 ± 5 µg∙min−1) and PMS (0.4 mM). Ozone, hydroxyl radical (HO•), and sulfate radical (SO4•−) were identified as contributors for ACE degradation and their contribution proportion was 27.1%, 25.4%, and 47.5% respectively. O3/PMS showed the best degradation performance at neutral pH and were sensitive to constituents such as chloride and natural organic matters. The qualitative analysis of degradation products confirmed the involvement of hydroxyl radical and sulfate radical and figured out that the active sites of ACE were the C=C bond, ether bond, and C-N bond. The electrical energy per order ACE degradation were calculated to be 4.6 kWh/m3. Our findings indicate that O3 is an efficient PMS activator and O3/PMS is promising due to its characteristic of tunable O3−HO• SO4•− ternary oxidant involving.

Hydroxyl radical-induced crosslinking and radiation-initiated hydrogel formation in dilute aqueous solutions of carboxymethylcellulose

2014 ◽  
Vol 112 ◽  
pp. 412-415 ◽  
Author(s):  
Radoslaw A. Wach ◽  
Bozena Rokita ◽  
Nina Bartoszek ◽  
Yosuke Katsumura ◽  
Piotr Ulanski ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Hydroxyl Radical ◽  
Hydrogel Formation ◽  
Dilute Aqueous Solutions

New insights into secondary organic aerosol from nitrate oxidation of isoprene in the atmospheric simulation chamber SAPHIR

2020 ◽  
Author(s):  
Juliane L. Fry ◽  
Bellamy Brownwood ◽  
Thorsten Hohaus ◽  
Avtandil Turdziladze ◽  
Philip Carlsson ◽  
...  
Keyword(s):  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Organic Nitrate ◽  
Nitrate Radical ◽  
Peroxy Radicals ◽  
Radical Reactivity ◽  
No3 Radical ◽  
Chemical Conditions ◽  
Seed Aerosol ◽  
Simulation Chamber

<p>Experiments at a set of atmospherically relevant conditions were performed in the atmospheric simulation chamber SAPHIR, investigating the oxidation of isoprene by the nitrate radical (NO3). A comprehensive set of instruments detected trace gases, radicals, aerosol properties and hydroxyl (OH) and NO3 radical reactivity. The chemical conditions in the chamber were varied to change the fate of the peroxy radicals (RO2) formed after the reaction between NO3 and isoprene, and seed aerosol of varying composition was added to initiate gas/aerosol partitioning. This presentation discusses observed gas/aerosol partitioning of the major organic nitrate products and summarizes the observations of secondary organic aerosol yield.</p>

Conductometric Pulse Radiolysis Study on the Reaction of the Solvated Electron with 5-Bromouracil in Aqueous Solutions at Different pH Values

1974 ◽  
Vol 29 (1-2) ◽  
pp. 86-88b ◽  
Author(s):  
Burkhard O. Wagner ◽  
Herbert Klever ◽  
Dietrich Schulte-Frohlinde
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Atom ◽  
Aqueous Solutions ◽  
Hydroxyl Radical ◽  
Rate Constant ◽  
Pulse Radiolysis ◽  
Solvated Electron ◽  
Ph Values

To study the reaction of the solvated electron with 5-bromouracil an aqueous solution has been examined by conductometric pulse radiolysis at pH values between 4.68 and 8.74. Alcohol was added to scavenge the hydrogen atom and the hydroxyl radical. G(Br—) = (2.64 ± 0.08)/100 eV was found to be independent of the pH. The mobility of the bromouracil mono-anion was measured to be (2.7 ± 0.2) 10-4 cm2 V-1 s-1 at 20°C, and the rate constant of reaction (3b) was determined to be k(H+ BrUr-) = (2.3 ± 0.2) 1010 I mole-1 s-1*.

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