Discreteness-of-charge effects in electrode kinetics. II. The electroreduction of hexamminocobalt(III) cation in the presence of specifically adsorbed nitrate anions

1983 ◽  
Vol 61 (12) ◽  
pp. 2821-2826 ◽  
Author(s):  
W. Ronald Fawcett ◽  
Kveta Markušová
Keyword(s):  
Ion Pairs ◽  
Electrode Reaction ◽  
Ion Concentration ◽  
Charge Effects ◽  
Interfacial Kinetics ◽  
Rate Of Reaction ◽  
Layer Effect ◽  
Kinetics Of ◽  
Nitrate Anions ◽  
Cation Nature

The kinetics of electroreduction of the hexamminocobalt(III) cation have been studied at a Hg electrode in aqueous solutions of NaNO3 + NaF and KNO3 + KF with an ionic strength of 0.2 M. The rate of reaction was observed to increase with increasing nitrate ion concentration but was independent of the cation nature. Analysis of the double layer effect for this system indicates that ion pairs formed between the reacting cation and anions of the base electrolyte also participate in the electrode reaction, and that attractive interactions between the reactant and adsorbed anions have a significant influence on the interfacial kinetics.

Discreteness-of-charge effects in electrode kinetics. III. The electroreduction of aquopentamminochromium(III) cation in the presence of specifically adsorbed iodide anions

1984 ◽  
Vol 62 (8) ◽  
pp. 1497-1501 ◽  
Author(s):  
W. Ronald Fawcett ◽  
Kveta Markušová
Keyword(s):  
Ionic Strength ◽  
Electrode Kinetics ◽  
Reaction Site ◽  
Charge Effects ◽  
Iodide Concentration ◽  
Rate Acceleration ◽  
Rate Of Reaction ◽  
Layer Effect ◽  
Kinetics Of ◽  
Outer Helmholtz Plane

The kinetics of electroreduction of the aquopentamminochromium(III) cation have been studied at a Hg electrode in acidified aqueous solutions of NaI+ NaClO4 with an ionic strength of 0.25 M. The rate of reaction increased with increase in iodide concentration due to the accelerating effect of this anion when it is adsorbed on the electrode. Analysis of the double layer effect indicates that the rate acceleration is greater than that predicted by the Frumkin theory chiefly because the reaction site is closer to the electrode than to the outer Helmholtz plane.

Discreteness-of-charge effects in electrode kinetics. I. The electroreduction of tetrathionate anion in the presence of specifically adsorbed iodide anions

1982 ◽  
Vol 60 (15) ◽  
pp. 2038-2045 ◽  
Author(s):  
W. Ronald Fawcett ◽  
Kveta Markušová
Keyword(s):  
Ionic Strength ◽  
Electrode Potential ◽  
Ion Concentration ◽  
Electrode Kinetics ◽  
Charge Effect ◽  
Charge Effects ◽  
Potential Analysis ◽  
Rate Of Reaction ◽  
Kinetics Of ◽  
Outer Helmholtz Plane

The kinetics of electroreduction of tetrathionate anion have been studied at a Hg electrode in aqueous solutions of Nal + NaF and KI + KF with an ionic strength of 0.25 M. The rate of reaction was observed to decrease as the iodide ion concentration was increased, and when the cation was changed from K+ to Na+ at constant electrode potential. Analysis of the double layer effects on the basis of the Frumkin model results in an overestimation of the repulsive effect of the adsorbed iodide anions. This result is interpreted on the basis of the discreteness-of-charge effect and the possible non-coincidence of the reaction plane and outer Helmholtz plane.

scholarly journals Redox Conversions of 5-Methyl-6-nitro-7-oxo-4,7-dihydro-1,2,4triazolo[1,5-a]pyrimidinide L-Arginine Monohydrate as a Promising Antiviral Drug

Molecules ◽  
2021 ◽  
Vol 26 (16) ◽  
pp. 5087
Author(s):  
Alexandra Ivoilova ◽  
Ludmila V. Mikhalchenko ◽  
Anton Tsmokalyuk ◽  
Marina Leonova ◽  
Andrey Lalov ◽  
...  
Keyword(s):  
Esr Spectroscopy ◽  
Nitroxyl Radical ◽  
Ion Pairs ◽  
Antiviral Drug ◽  
Electrode Reaction ◽  
Buffer Solution ◽  
Simultaneous Formation ◽  
Two Stages ◽  
Kinetics Of ◽  
Second Peak

This article presents the results of a study of electrochemical transformations in aqueous and aprotic media of 5-methyl-6-nitro-7-oxo-4,7-dihydro-1,2,4-triazolo[1,5-a]pyrimidinide l-arginine monohydrate (1a, Triazid) obtained by electrochemical methods and ESR spectroscopy. The effect of pH on the current and the reduction potential of 1a in an aqueous Britton–Robinson buffer solution was studied. It was found that 1a is irreversibly reduced in aqueous acidic media on a glassy carbon electrode in one stage with the participation of six electrons and the formation of 5-methyl-6-amino-7-oxo-1,2,4-triazolo[1,5-a]pyrimidin. The electroreduction of 1a in DMF on a background of tetrabutylammonium salts proceeds in two stages, controlled by the kinetics of second-order reactions. In the first stage, the reduction of 1a is accompanied by protonation by the initial compound of the basic intermediate products formed in the electrode reaction (self-protonation mechanism). The second quasi-reversible stage of the electroreduction 1a corresponds to the formation of a dianion radical upon the reduction of the heterocyclic anion 5-methyl-6-nitro-7-oxo-4,7-dihydro-1,2,4-triazolo[1,5-a]pyrimidin, which is formed upon the potentials of the first peak. The ESR spectrum of the radical dianion was recorded upon electroreduction of Triazid in the presence of Bu4NOH. The effect of the formation of ion pairs on the reversibility of the second peak of the 1a transformation is shown. A change in the rate and regioselectivity of the protonation of the dianion radical in the presence of Na+ and Li+ ions is assumed. The results of studying the electroreduction of 1a by ESR spectroscopy with a TEMPO trap make it possible to assume the simultaneous formation of both a nitroxyl radical and a radical with the spin density localized on the nitrogen at the 4 position of the six-membered ring.

scholarly journals The mechanism of the iodination of aminochromes

1967 ◽  
Vol 45 (15) ◽  
pp. 1721-1725 ◽  
Author(s):  
G. L. Mattok ◽  
D. L. Wilson
Keyword(s):  
Potassium Iodide ◽  
Molecular Iodine ◽  
Reactive Species ◽  
Base Catalysis ◽  
Ion Concentration ◽  
Zwitterionic Form ◽  
General Base ◽  
Rate Of Reaction ◽  
Reaction Proceeds ◽  
Kinetics Of

The kinetics of the iodination of several aminochromes by iodine in aqueous potassium iodide, to form the 7-iodo derivatives, have been studied. The rate of iodination is directly dependent on the concentrations of the aminochrome and iodine and varies inversely with the first power of the iodide ion concentration. The rate of reaction is independent of pH, but the reaction is subject to general base catalysis. A mechanism for the iodination of aminochromes is proposed. The reactive species are molecular iodine and the zwitterionic form of adrenochrome, and the reaction proceeds via a quinonoid intermediate. The rate-controlling process is the removal of the C-7 proton.

In Operando Detection of the Physical Properties Change of the Interfacial Electrolyte during Li-Metal Electrode Reaction by Atomic Force Microscopy

2020 ◽  
Author(s):  
Mitsunori Kitta
Keyword(s):  
Atomic Force Microscopy ◽  
Energy Dissipation ◽  
Physical Properties ◽  
Electrode Surface ◽  
Electrode Reaction ◽  
Metal Electrode ◽  
Ion Concentration ◽  
Force Microscopy ◽  
Atomic Force ◽  
Discharge Reaction

This manuscript propose the operando detection technique of the physical properties change of electrolyte during Li-metal battery operation.The physical properties of electrolyte solution such as viscosity (η) and mass densities (ρ) highly affect the feature of electrochemical Li-metal deposition on the Li-metal electrode surface. Therefore, the operando technique for detection these properties change near the electrode surface is highly needed to investigate the true reaction of Li-metal electrode. Here, this study proved that one of the atomic force microscopy based analysis, energy dissipation analysis of cantilever during force curve motion, was really promising for the direct investigation of that. The solution drag of electrolyte, which is controlled by the physical properties, is directly concern the energy dissipation of cantilever motion. In the experiment, increasing the energy dissipation was really observed during the Li-metal dissolution (discharge) reaction, understanding as the increment of η and ρ of electrolyte via increasing of Li-ion concentration. Further, the dissipation energy change was well synchronized to the charge-discharge reaction of Li-metal electrode.This study is the first report for direct observation of the physical properties change of electrolyte on Li-metal electrode reaction, and proposed technique should be widely interesting to the basic interfacial electrochemistry, fundamental researches of solid-liquid interface, as well as the battery researches.

The Effect of Concentration and Nature of Different Supporting Electrolytes on the Kinetics of the Electrode Reaction of Benzalacetophenone

1988 ◽  
Vol 269O (1) ◽  
Author(s):  
M. M. Srivastava ◽  
S. Srivastava ◽  
S. N. Srivastava
Keyword(s):  
Electrode Reaction ◽  
Kinetics Of

Copolymerization of Isobutene and Isoprene at “High” Temperature with Syncatalyst Systems Based on Aluminum Organic Compounds

1976 ◽  
Vol 49 (4) ◽  
pp. 937-959 ◽  
Author(s):  
S. Cesca ◽  
M. Bruzzone ◽  
A. Priola ◽  
G. Ferraris ◽  
P. Giusti
Keyword(s):  
Energy Savings ◽  
Ion Pairs ◽  
Great Part ◽  
Methyl Chloride ◽  
Reactivity Ratio ◽  
Experimental Conditions ◽  
Noticeable Increase ◽  
Catalyst Systems ◽  
Kinetics Of ◽  
Kinetics Of Vulcanization

Abstract New catalyst systems based on alkylaluminum derivatives and halogen or interhalogen compounds were found highly efficient in the synthesis of high-molecular-weight IIR at temperatures above − 50°C. The reaction mechanism was studied in detail for the system Et2AlCl + Cl2. The reactions occurring between chlorine, isobutene, Et2AlCl, and the solvent (CH3Cl) were elucidated and studied under various experimental conditions (e.g. presence or absence of light, simultaneous presence of the copolymerization system components, temperature, type of halogen, use of model compound of isobutene). It was concluded that halogenium ions, i.e. Cl+, Br+, or I+, are the initiating species. Kinetic and conductometric investigations showed that scarcely dissociated ion pairs, e.g. Cl+[Et2AlCl2]−, were formed in the absence of monomer; but in the presence of isobutene, a noticeable increase of the electrical conductivity and rapid polymerization occurred. The maximum polymerization rate was first order with respect to the concentrations of monomer, Cl2, and Et2AlCl. In the homopolymerization of isobutene, transfer to monomer and termination reactions were negligible. The MW of IIR was found to be mainly dependent on the concentrations of the catalyst components, on isoprene concentration, and on temperature. The reactivity ratio of isobutene with isoprene was found to be r1=2.5±0.5 at −35°C, while the activation energies relative to MW were −5.8 ± 0.4, kcal/mol for polyisobutene, and −5.7 ± 0.7 and − 4.3 ± 0.5 kcal/mol for IIR containing, respectively, 1.3 and 1.9 mol% of isoprene. The evaluation of some physicochemical and technological properties of typical IIR produced with the system Et2AlCl + Cl2, indicated that isoprene is randomly distributed along the chains and that the MWD is monomodal, while the glass transition temperature, tensile properties, mechanical-dynamic spectra, and kinetics of vulcanization are very similar to those of commercial IIR. Very preliminary data, referring to several classes of new catalyst systems yielding IIR having good properties, were also obtained. The syncatalyst systems here described can work in a homogeneous phase consisting of an aliphatic hydrocarbon besides methyl chloride, still giving IIR with high MW. Therefore, a completely homogeneous process can be envisioned for the synthesis of IIR at −50°C thus avoiding a great part of the fouling problems of the slurry process. The economic advantage of using “high” temperatures of polymerization is briefly discussed in terms of energy savings.

THE ALKALINE CLEAVAGE OF o-NITROBENZYLTRIMETHYLSILANE SOLVENT EFFECTS IN THE DIOXANE–WATER SYSTEM

1963 ◽  
Vol 41 (6) ◽  
pp. 1525-1530 ◽  
Author(s):  
H. R. Allcock
Keyword(s):  
Transition State ◽  
Solvent Effects ◽  
Water System ◽  
Solvent Polarity ◽  
High Water ◽  
Aqueous Dioxane ◽  
Alkaline Cleavage ◽  
Rate Of Reaction ◽  
Kinetics Of

The kinetics of alkaline cleavage of o-nitrobenzyltrimethylsilane were examined in aqueous dioxane media. At high water concentrations, increases in solvent polarity retard the cleavage, as required by a mechanism involving charge dispersion in the transition state. At high dioxane concentrations, solvent polarity increases are accompanied by increases in the rate of reaction, a result which may reflect association between the solvent components.

Automated Fluoride Ion Determination

1977 ◽  
Vol 14 (1-6) ◽  
pp. 269-274 ◽  
Author(s):  
David C. Cowell
Keyword(s):  
Continuous Flow ◽  
Ion Concentration ◽  
Fluoride Ion ◽  
Selective Electrode ◽  
Automated Method ◽  
Electrode Response ◽  
Kinetics Of ◽  
Fluoride Ion Selective Electrode ◽  
Flow Techniques

An automated method is described, using standard continuous flow techniques, for the determination of urine fluoride ion concentration using a fluoride ion selective electrode. It is shown that the kinetics of the electrode response to changes in fluoride ion can be used for the accurate measurement of fluoride ion concentration in urine, and that equilibration of the electrode response is not a prerequisite for the measurement of fluoride ion. Recovery experiments are in the range 83 to 90%; in-batch precision is between 0·9 and 1·6% and carryover 2·5% or less.

Kinetics of the Variation in the Magnetic Impurity Ion Concentration in Pb1–x–ySn x V y Te Alloys upon Doping

2018 ◽  
Vol 52 (7) ◽  
pp. 828-835
Author(s):  
E. P. Skipetrov ◽  
N. S. Konstantinov ◽  
L. A. Skipetrova ◽  
A. V. Knotko ◽  
V. E. Slynko
Keyword(s):  
Magnetic Impurity ◽  
Ion Concentration ◽  
Impurity Ion ◽  
Kinetics Of
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