Redox reaction mechanisms in non-complementary processes. Part I. Redox reactions between the tetrabromobismethylaminoplatinum(IV)–dibromobismethylaminoplatinum(II) and iron(III)–iron(II) systems in the presence of bromide ions

1971 ◽  
Vol 0 (0) ◽  
pp. 725-729 ◽  
Author(s):  
A. Peloso ◽  
M. Basato
Keyword(s):  
Reaction Mechanisms ◽  
Redox Reaction ◽  
Redox Reactions ◽  
Bromide Ions

Cr(vi) removal by combined redox reactions and adsorption using pectin-stabilized nanoscale zero-valent iron for simulated chromium contaminated water

RSC Advances ◽  
2015 ◽  
Vol 5 (80) ◽  
pp. 65068-65073 ◽  
Author(s):  
Dan Chen ◽  
Kai Yang ◽  
Hongyu Wang ◽  
Jun Zhou ◽  
Huining Zhang
Keyword(s):  
Redox Reaction ◽  
Redox Reactions ◽  
Zero Valent Iron ◽  
Contaminated Water ◽  
Nanoscale Zero Valent Iron

Pectin-stabilized nanoscale zero-valent iron was used to removal Cr(vi) and the main mechanisms were redox reaction and adsorption.

scholarly journals Studi Perbandingan Pengajaran Reaksi Reduksi Oksidasi Antara Cara Perubahan Bilangan Oksidasi dengan Cara Setengah Reaksi terhadap Hasil Belajar Siswa Kelas XII IPA 1 dan XII IPA 2

2021 ◽  
Vol 21 (1) ◽  
pp. 353
Author(s):  
Fauziah Fauziah
Keyword(s):  
Redox Reaction ◽  
Redox Reactions ◽  
Oxidation Number ◽  
Reduction Reactions ◽  
Reaction Method ◽  
Oxidation Reduction ◽  
Reaction Coefficient ◽  
Level Of Significance ◽  
Student Grades ◽  
Train Of Thought

Oxidation-Reduction Reactions (Redox) are one of the hardest reactions to equalize, this means that it is hard to determine the suitable Reaction Coefficient. An easier and more logical train of thought is to remember that a Reduction and an Oxidation reaction happens simultaneously. A Redox Reaction has two methods in order to equalize, that which is by using the “Change in Oxidation Number” method or the “Half-Reaction (Ion-Electron)” method. The students’ skills in completing a Redox Reaction can be observed in the grades that they have achieved. This observation is intended to find out if there is a difference in students’ grades if you were to teach them about the equalization of Redox Reactions using either of these two methods (the “Change in Oxidation Number” method and the “Half-Reaction” method).  The population in this observation consists of the students of Class XII IPA 1 and Class XII IPA 2 of SMAS PERTIWI Jambi that are studying Oxidation-Reduction Reactions. Sample members consist of the students of Class XII IPA 1 and the students of Class XII IPA 3 of SMAS Pertiwi Jambi. The measuring instrument used is a test that has fulfilled standards. Normality tests and Homogeneity tests of the sample in question has been done before the Hypothetical test was implemented.  The average grades of students using the “Change in Oxidation Number” method and the “Half-Reaction” method is 11.75 and 10.8 respectively. The T-value of calculations is approximately 1.81 while the T-value of tables is approximately 2.00. With the Level of Significance being 0.05.  From the data provided above, it can be concluded that there is no difference in student grades whether the “Change in Oxidation Numbers” method or the “Half-Reaction” method is used to equalize Redox Reactions in applicative aspects.

A review of non-precious metal single atom confined nanomaterials in different structural dimensions (1D–3D) as highly active oxygen redox reaction electrocatalysts

2020 ◽  
Vol 8 (5) ◽  
pp. 2222-2245 ◽  
Author(s):  
Jin Liu ◽  
Hao Zhang ◽  
Ming Qiu ◽  
Zehua Peng ◽  
Michael K. H. Leung ◽  
...  
Keyword(s):  
Redox Reaction ◽  
Precious Metal ◽  
Redox Reactions ◽  
Active Oxygen ◽  
Single Atom ◽  
Highly Active ◽  
Structural Dimensions

Different dimensional supports for non-precious-metal single-atom catalysts play significant roles in their fabrication and electrocatalytic activities for oxygen redox reactions.

scholarly journals A synthetic chemist's guide to electroanalytical tools for studying reaction mechanisms

2019 ◽  
Vol 10 (26) ◽  
pp. 6404-6422 ◽  
Author(s):  
Christopher Sandford ◽  
Martin A. Edwards ◽  
Kevin J. Klunder ◽  
David P. Hickey ◽  
Min Li ◽  
...  
Keyword(s):  
Reaction Mechanisms ◽  
Redox Reactions ◽  
Synthetic Chemistry

A range of electroanalytical tools can be applied to studying redox reactions, probing key mechanistic questions in synthetic chemistry.

The effect that comparing molecular animations of varying accuracy has on students’ submicroscopic explanations

2017 ◽  
Vol 18 (4) ◽  
pp. 582-600 ◽  
Author(s):  
Resa M. Kelly ◽  
Sevil Akaygun ◽  
Sarah J. R. Hansen ◽  
Adrian Villalta-Cerdas
Keyword(s):  
General Chemistry ◽  
Experimental Evidence ◽  
Reaction Mechanisms ◽  
Redox Reaction ◽  
Molecular Level ◽  
Electron Exchange ◽  
The Other ◽  
First Semester ◽  
Chemistry Students ◽  
Solid Copper

In this qualitative study, we examined how a group of seventeen first semester General Chemistry students responded when they were shown contrasting molecular animations of a reduction–oxidation (redox) reaction between solid copper and aqueous silver nitrate for which they first viewed a video of the actual experiment. The animations contrasted in that they portrayed different reaction mechanisms for the redox reaction. One animation was scientifically accurate and reflected an electron exchange mechanism, while the other was purposefully inaccurate and represented a physical exchange between the ions. Students were instructed to critique each animation for its fit with the experimental evidence and to ultimately choose the animation that they felt best depicted the molecular level of the chemical reaction. Analyses showed that most students identified that the electron exchange animation was the more scientifically accurate animation; however, approximately half of the students revised their drawings to fit with the inaccurate physical exchange animation. In addition, nearly all students thought that both animations were correct and useful for understanding salient information about the redox reaction. The results indicate that when students are shown contrasting animations of varying accuracy they make errors in deciding how the animations are supported and refuted by the evidence, but the treatment is effective. Contrasting animations promote students to think deeply about how animations fit with experimental evidence and is a promising way to engage students to think deeply about animations.

scholarly journals One-electron oxidation of ergothioneine and analogues investigated by pulse radiolysis: redox reaction involving ergothioneine and vitamin C

1996 ◽  
Vol 315 (2) ◽  
pp. 625-629 ◽  
Author(s):  
Klaus-Dieter ASMUS ◽  
René V. BENSASSON ◽  
Jean-Luc BERNIER ◽  
Raymond HOUSSIN ◽  
Edward J. LAND
Keyword(s):  
Oxidative Stress ◽  
Vitamin E ◽  
Vitamin C ◽  
Redox Reaction ◽  
Redox Reactions ◽  
Pulse Radiolysis ◽  
Antioxidant Properties ◽  
Transient Species ◽  
Rapid Reduction ◽  
The One

Redox reactions of endogenous and exogenous sulphur-containing compounds are involved in protection against oxidative damage arising from the incidence and/or treatment of many diseases, including cancer. We have investigated, via pulse radiolysis, the one-electron oxidation of ergothioneine, a molecule with antioxidant properties which is detected at millimolar concentrations in certain tissues and fluids subject to oxidative stress, including erythrocytes and plasma. The spectrum of the transient species, assigned to the product of one-electron oxidation, observed after reaction of ergothioneine with the oxidizing radicals OH•, N3• and CCl3O2• has a maximum absorption at 520 nm and is very similar to that obtained by oxidation of analogous molecules such as 2-mercaptoimidazole, 1-methyl-2-mercaptoimidazole, S-methyl- and S,N-dimethyl-ergothioneine. In the presence of vitamin C, the oxidized form of ergothioneine is repaired by a rapid reduction (k = 6.3×108 M-1·s-1) producing ascorbyl radicals. This co-operative interaction between ergothionine and ascorbate, similar to that previously observed between vitamin E and ascorbate, may contribute to essential biological redox protection.

Biopolymer Solution Viscosity Stabilization - Polymer Degradation and Antioxidant Use

1983 ◽  
Vol 23 (06) ◽  
pp. 901-912 ◽  
Author(s):  
Scott L. Wellington
Keyword(s):  
Free Radicals ◽  
Chemical Treatment ◽  
Reaction Mechanisms ◽  
Redox Reactions ◽  
Polymer Degradation ◽  
Mobility Control ◽  
Solution Viscosity ◽  
Degradation Mechanisms ◽  
Literature Study ◽  
Shear Stability

Abstract Dilute solutions of polymers used to provide mobility control for EOR often lose viscosity. especially at higher temperatures. This loss of viscosity with time brings into question the feasibility of using polymers as mobility-control agents. A literature study of the many possible reaction mechanisms indicated that oxidation/reduction (redox) reactions involving free radicals probably caused polymer degradation and concomitant viscosity loss. A preliminary search for antioxidants known to retard free-radical reactions located several types and positive synergistic formulations that significantly retarded biopolymer solution viscosity loss during accelerated tests at high temperature. The most effective type formulation found contained (1) a radical transfer agent; (2) a sacrificial, easily oxidizable alcohol; (3) a compatible oxygen scavenger; and (4) sufficient brine concentration. Samples prepared with this technology have not lost viscosity after 1-year storage at 207 deg. F [97 deg. C]. A high-surface-area effect (so-called "wall effect") known to retard radical propagation, was also found to operate in the presence of sandpacks; this should be beneficial in porous media. The variables and beneficial antioxidant formulations identified in this study allow tentative conclusions and recommendations regarding biopolymer mixing and handling procedures prior to injection. Introduction Two commercially available polymers are currently considered suitable for mobility control. They are (1) the synthetically prepared polyacrylamides, and (2) the biopolymer (xanthan gum) prepared by fermenting the bacterium Xanthomonas campestris and collecting the exude gum. The major advantages of the biopolymer over polyacrylamides are the good shear stability and the good thickening power at high salinity. The major disadvantages of the biopolymer have been the high cost, the difficulty of preparing solutions that do not plug core material, and the prevention of viscosity loss from biochemical or chemical reactions. The requirement of shear stability and tolerance to salts, especially multivalent cations, significantly reduces the number of reservoirs where polyacrylamides can be used. Biopolymer solution-preparation problems have been overcome by development of solution processes including proper mixing equipment, chemical addition-both caustic and enzymes-and filtration techniques. Biopolymer broths, which preclude the need to wet and disperse a dry powder, are also available. Chemical stability of the polymer is the subject of this report. A literature study of the various reaction mechanisms indicates that redox reactions involving free radicals probably cause polymer degradation and concomitant viscosity losses. This is undoubtedly the type of reaction responsible for polyacrylamide decomposition. Removal of oxygen with excess sodium dithionite appears to provide sufficient chemical treatment to prevent autoxidation of polyacrylamide. This straightforward chemical treatment did not prevent biopolymer-solution viscosity loss, and further antioxidant addition was required to stabilize the solution viscosity. Polysaccharide Degradation Mechanisms A literature review of polysaccharide chemistry suggested thermal, biological, mechanical, radiation, and chemical as the most important degradation mechanisms. Thermal- and radiation-induced degradation mechanisms were discounted since biopolymers should not be used if the reservoir is too hot or too radioactive. SPEJ P. 901^

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