Influence of Aqueous Mixtures of Amides on the Kinetics of Electro Reduction of Ni(II) and Co(II) at d. m. e.

1975 ◽  
Vol 30 (11-12) ◽  
pp. 859-861 ◽  
Author(s):  
S. K. Jha ◽  
S. Jha ◽  
S. N. and
Keyword(s):  
Rate Constants ◽  
Electrode Potential ◽  
Gradual Decrease ◽  
Electrode Kinetics ◽  
Aqueous Mixtures ◽  
Aqueous Mixture ◽  
Kinetics Of ◽  
Remarkable Agreement ◽  
Amide Content

Electroreduction of Ni(II) and Co(II) has been carried out in aqueous mixtures of formamide, acetamide and urea. Electrode kinetics in terms of theories of irreversible waves have been studied. After calculating the rate constants by DELAHAY1 and Kou-TECKY2 treatments separately their variation with electrode potential has been used to calculate the product ‘ana’. The rate constants and ‘ana’ calculated from two different approaches show remarkable agreement. `ana’ records a gradual decrease with increasing amide content of the aqueous mixture.

Electrode kinetics of the system V(III)/V(II) in aqueous dimethylsulphoxide

1991 ◽  
Vol 56 (1) ◽  
pp. 90-95 ◽  
Author(s):  
Libuše Kišová ◽  
Libor Reichstädter ◽  
Jaro Komenda
Keyword(s):  
Organic Solvent ◽  
Double Layer ◽  
Rate Constants ◽  
Electrode Surface ◽  
Reaction Rate ◽  
Mercury Electrode ◽  
Electrode Reaction ◽  
Electrode Kinetics ◽  
Kinetics Of ◽  
Lower Basicity

The rate constants for the reduction of V(III) and oxidation of V(II) were measured on a mercury electrode in water and water-dimethylsulphoxide mixtures. Their dependance on the concentration of DMSO differs from that in mixtures of water with an organic solvent of lower basicity. This can be attributed to the existence of different solvates of vanadium in solutions and to different values of the rate constant for these solvates on the electrode surface at different coverages with the organic component. The influence of DMSO both in the primary solvation sphere and in the electrode double layer on the electrode reaction rate is discussed.

Kinetics and mechanism of oxidation of nickel(II) tetraazamacrocycles by the peroxydisulphate anion in aqueous and binary aqueous mixtures

1992 ◽  
Vol 70 (11) ◽  
pp. 2785-2791 ◽  
Author(s):  
Robert I. Haines ◽  
Sandra J. Northcott
Keyword(s):  
Rate Constants ◽  
Metal Ion ◽  
Ion Pairing ◽  
Ion Pair ◽  
Aqueous Mixtures ◽  
Kinetics Of Oxidation ◽  
Steric Factors ◽  
Temperature Dependences ◽  
Mechanism Of Oxidation ◽  
Kinetics Of

The kinetics of oxidation of several nickel(II) tetraazamacrocycles by the peroxydisulphate anion have been studied in water and in binary aqueous mixtures. The reactions proceed via an ion-pairing pre-equilibrium, followed by metal ion-assisted peroxy-bond fissure within the ion-pair solvent shell. The derived rate law is[Formula: see text]Ion-pairing constants have been determined and have been found to be little influenced by steric factors, but do depend on solvent composition. Rate constants have been extracted using the rate expression and activation energies have been estimated from temperature dependences.

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.

Electrode Kinetics of the Ti(IV)/Ti(III) System in Water and in WaterDimethylformamide and WaterDimethyl Sulfoxide Mixed Solvents

1994 ◽  
Vol 59 (6) ◽  
pp. 1279-1286 ◽  
Author(s):  
Libuše Kišová ◽  
Šárka Šotková ◽  
Ivana Komendová
Keyword(s):  
Rate Constants ◽  
Transfer Rate ◽  
Catalytic Effect ◽  
Mixed Solvents ◽  
Electrode Reaction ◽  
Electrode Kinetics ◽  
Electron Transfer Rate ◽  
Standard Rate ◽  
Electrode Coverage ◽  
Kinetics Of

The electron transfer rate constants in the reduction of Ti4+ and oxidation of Ti3+ in water and in water DMF and water DMSO mixtures were determined by square-wave polarography and by analysis of the DC and pulse polarographic curves. The two reactions occur at different potentials due to the rapid consecutive transformation of the primary product of the electrode reaction. Thus the rate constants are no standard rate constants, and depend on the method employed. The effect of the organic co-solvent varies for both reactions as a consequence of dependence of the degree of electrode coverage on potential. Generally, the adsorbed organic substance exerts an accelerating catalytic effect.

Kinetics of Electrochemical Reductive Dissolution of Iron(III) Hydroxy-oxides

1995 ◽  
Vol 60 (8) ◽  
pp. 1261-1273 ◽  
Author(s):  
Tomáš Grygar
Keyword(s):  
Rate Constants ◽  
Electrode Potential ◽  
Surface Reaction ◽  
Stripping Voltammetry ◽  
Dissolution Process ◽  
Reductive Dissolution ◽  
Working Electrode ◽  
Natural Iron ◽  
Kinetics Of

Abrasive stripping voltammetry was applied to the chronoamperometric and voltammetric investigation of the kinetics of reductive dissolution of synthetic and natural iron(III) hydroxy-oxides. Conditions were found under which the dissolution process can be described by equations derived for and applied to the surface reaction of the particles. The rate constants obtained were employed to compare the electrochemical and chemical reductive dissolution and to quantitatively evaluate the effect of adsorbing ions, pH, and working electrode potential.

Submerged upflow biotower operation and computer simulation

1994 ◽  
Vol 30 (11) ◽  
pp. 143-146
Author(s):  
Ronald D. Neufeld ◽  
Christopher A. Badali ◽  
Dennis Powers ◽  
Christopher Carson
Keyword(s):  
Computer Simulation ◽  
Benzoic Acid ◽  
Computer Model ◽  
Rate Constants ◽  
Batch Mode ◽  
Operational Conditions ◽  
First Order ◽  
Low Concentrations ◽  
Biological Transformation ◽  
Kinetics Of

A two step operation is proposed for the biodegradation of low concentrations (< 10 mg/L) of BETX substances in an up flow submerged biotower configuration. Step 1 involves growth of a lush biofilm using benzoic acid in a batch mode. Step 2 involves a longer term biological transformation of BETX. Kinetics of biotransformations are modeled using first order assumptions, with rate constants being a function of benzoic acid dosages used in Step 1. A calibrated computer model is developed and presented to predict the degree of transformation and biomass level throughout the tower under a variety of inlet and design operational conditions.

Kinetics of hydrolysis of peroxodisulphate ions in acidic medium to peroxomonosulphuric acid

1981 ◽  
Vol 46 (5) ◽  
pp. 1229-1236 ◽  
Author(s):  
Jan Balej ◽  
Milada Thumová
Keyword(s):  
Ionic Strength ◽  
Rate Constants ◽  
Acidic Medium ◽  
Measured Data ◽  
Molar Ratios ◽  
Starting Solution ◽  
Kinetics Of Hydrolysis ◽  
Rate Of Hydrolysis ◽  
Kinetics Of ◽  
Hydrolysis Of

The rate of hydrolysis of S2O82- ions in acidic medium to peroxomonosulphuric acid was measured at 20 and 30 °C. The composition of the starting solution corresponded to the anolyte flowing out from an electrolyser for production of this acid or its ammonium salt at various degrees of conversion and starting molar ratios of sulphuric acid to ammonium sulphate. The measured data served to calculate the rate constants at both temperatures on the basis of the earlier proposed mechanism of the hydrolysis, and their dependence on the ionic strength was studied.

Kinetics of the reaction between hexamethylenediisocyanate and 1-pentanol

1983 ◽  
Vol 48 (11) ◽  
pp. 3279-3286
Author(s):  
Slavko Hudeček ◽  
Miloslav Bohdanecký ◽  
Ivana Hudečková ◽  
Pavel Špaček ◽  
Pavel Čefelín
Keyword(s):  
Liquid Chromatography ◽  
Rate Constants ◽  
Reversed Phase ◽  
Order Reaction ◽  
Second Order ◽  
Second Order Reaction ◽  
Reversed Phase Liquid Chromatography ◽  
Consecutive Reactions ◽  
Phase Liquid ◽  
Kinetics Of

The reaction between hexamethylenediisocyanate and 1-pentanol in toluene was studied by means of reversed-phase liquid chromatography. By employing this method, it was possible to determine all components of the reaction mixture including both products, i.e. N-(6-isocyanate hexyl)pentylcarbamate and N,N'-bis(pentyloxycarbonyl)hexamethylenediamine. Relations for the calculation of kinetic constants were derived assuming a competitive consecutive second-order reaction. It was demonstrated that the reaction involved in this case is indeed a second-order reaction, and the rate constants of the first and second consecutive reactions were determined.

Kinetics of esterification of monoisopropylphenols with phosphoryl trichloride

1989 ◽  
Vol 54 (5) ◽  
pp. 1311-1317
Author(s):  
Miroslav Magura ◽  
Ján Vojtko ◽  
Ján Ilavský
Keyword(s):  
Liquid Phase ◽  
Rate Constants ◽  
Reaction Rates ◽  
Activation Energies ◽  
The Individual ◽  
Kinetics Of

The kinetics of liquid-phase isothermal esterification of POCl3 with 2-isopropylphenol and 4-isopropylphenol have been studied within the temperature intervals of 110 to 130 and 90 to 110 °C, respectively. The rate constants and activation energies of the individual steps of this three-step reaction have been calculated from the values measured. The reaction rates of the two isomers markedly differ: at 110 °C 4-isopropylphenol reacts faster by the factors of about 7 and 20 for k1 and k3, respectively. This finding can be utilized in preparation of mixed triaryl phosphates, since the alkylation mixture after reaction of phenol with propene contains an excess of 2-isopropylphenol over 4-isopropylphenol.

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