Electron transfer between ferrocene and hexacyanoferrate(III) across the water/1,2-dichloroethane interface

1988 ◽  
Vol 53 (5) ◽  
pp. 903-911 ◽  
Author(s):  
Josef Hanzlík ◽  
Jan Hovorka ◽  
Zdeněk Samec ◽  
Štefan Toma
Keyword(s):  
Electron Transfer ◽  
Aqueous Phase ◽  
Rate Constant ◽  
Potential Range ◽  
Ion Transfer ◽  
Potential Sweep ◽  
Experimental Conditions ◽  
Chemical Decomposition ◽  
Kinetics Of

Kinetics of electron transfer between ferrocene or its derivative (1,1'-diethyl- or 1,1'-distearoylferrocene) in dichloroethane and hexacyanoferrate(III) in water was studied by means of convolution potential sweep voltammetry. Within the accessible range of experimental conditions no effect of either the potential or concentrations of reactants on the rate constant of electron transfer from the organic to the aqueous phase (ko→w = 1 . 10-7 m4 mol-1 s-1) was observed. Electron transfer was shown to occur far from the potential range, in which the ferricenium ion transfer can take place. However, the reaction was complicated by the chemical decomposition of ferricenium in dichloroethane (k = 0·346 s-1).

Voltammetric investigation of the kinetics of alkali metal cation reduction in N,N-dimethylformamide

1975 ◽  
Vol 28 (2) ◽  
pp. 237 ◽  
Author(s):  
JW Diggle ◽  
AJ Parker ◽  
DA Owensby
Keyword(s):  
Electron Transfer ◽  
Alkali Metal ◽  
Propylene Carbonate ◽  
Rate Constant ◽  
Alkali Metal Cation ◽  
Electrode Reaction ◽  
Amalgam Electrode ◽  
Kinetics Of ◽  
Dipolar Aprotic Solvents

The standard electron-transfer heterogeneous rate constant of lithium, potassium, sodium and caesium amalgams in N,N-dimethylformamide was ascertained employing cyclic voltammetry in an effort to relate the presence of a non-equilibrium electrode reaction at the dropping lithium amalgam electrode to the variation of the lithium amalgam electrode potential with amalgam electrode con- figuration, i.e. whether streaming, dropping or stationary. Such variations are not observed at other alkali metal amalgam electrodes. ��� In the dipolar aprotic solvents the standard electron-transfer heterogeneous rate constant for the Li(Hg) electrode increases as the solvating power for Li+ decreases, i.e. dimethyl sulphoxide < di- methylformamide < propylene carbonate. Water is a much stronger solvator of Li+ than is propylene carbonate, but the electron transfer is faster in water than in propylene carbonate; the important role of entropic contributions in ion solvation is discussed as an explanation.

Kinetics of tunneling electron transfer in the presence of scatter in the parameters of the tunneling rate constant

1985 ◽  
Vol 113 (5) ◽  
pp. 467-470 ◽  
Author(s):  
A.I. Fiksel ◽  
V.P. Zhdanov ◽  
V.N. Parmon
Keyword(s):  
Electron Transfer ◽  
Rate Constant ◽  
Tunneling Rate ◽  
Tunneling Electron ◽  
Kinetics Of

FT-EPR Study of Spin-correlated Radical Pairs Formed by Electron Transfer Quenching of Porphyrin Triplets in Micellar Solution

1998 ◽  
Vol 02 (04) ◽  
pp. 353-361 ◽  
Author(s):  
VOLKER WEIS ◽  
HANS VAN WILLIGEN
Keyword(s):  
Electron Transfer ◽  
Statistical Model ◽  
Rate Constant ◽  
Micellar Solution ◽  
Transfer Reaction ◽  
Electron Transfer Reaction ◽  
Cetyltrimethylammonium Chloride ◽  
Radical Pairs ◽  
Homogeneous Solutions ◽  
Kinetics Of

The spin-correlated radical pairs (SCRPs) formed by photoinduced electron transfer from zinc tetrakis(4-sulfonatophenyl)porphyrin ( ZnTPPS ) to quinones in micelles of the cationic surfactant cetyltrimethylammonium chloride ( CTAC ) were studied by means of Fourier transform EPR (FT-EPR). It is shown that variation of the power of the microwave pulse allows the separation of EPR signals arising from SCRPs and free radicals. The measured kinetics of radical formation can be accounted for in terms of a statistical model taking into account the non-uniform distribution of the solutes over the micelles. The rate constant of electron transfer quenching (kq) of the ZnTPPS triplet state by duroquinone (DQ) is found to be 1.05 × 106 s−1. The FT-EPR measurements gave information also on the kinetics of the homogeneous electron transfer reaction DQ − + DQ → DQ + DQ − in CTAC solution in which the DQ − anion radicals were generated by light-induced electron transfer from ZnTPPS . It is found that the dependence of the rate of this reaction on quinone concentration deviates from the linear relationship found in homogeneous solutions. A statistical model is proposed to account for the data. Based on this model, the rate constant of the self-exchange reaction (k ex ) is 4.1 × 106 s−1. From results obtained with duroquinone and benzoquinone as acceptors, it is concluded that ZnTPPS is located at the micelle/water interface.

Dissociation kinetics of potassium anion in methylamine

1980 ◽  
Vol 58 (11) ◽  
pp. 1151-1153 ◽  
Author(s):  
Y. Harima ◽  
H. Kurihara ◽  
S. Aoyagui
Keyword(s):  
Rate Constant ◽  
Supporting Electrolyte ◽  
Order Rate Constant ◽  
Dissociation Kinetics ◽  
Potential Sweep ◽  
Solvated Electrons ◽  
Potential Step ◽  
First Order ◽  
Order Rate ◽  
Kinetics Of

The potential-sweep voltammograms of solvated electrons in methylamine containing KI as the supporting electrolyte demonstrate the coexistence of one- and two-electron species in equilibrium. The it1/2 vs. log t curve obtained with potential-step chronoamperometry exhibits a transient part between two plateaux. The analysis of this curve yields the approximate value of 102 s−1 for the first-order rate constant of the dissociation of the two-electron species, K−.

Kinetics and mechanism of the oxidation of mercury by peroxidase

1985 ◽  
Vol 63 (11) ◽  
pp. 2940-2944 ◽  
Author(s):  
Donald C. Wigfield ◽  
Season Tse
Keyword(s):  
Hydrogen Peroxide ◽  
Electron Transfer ◽  
Horseradish Peroxidase ◽  
Rate Constant ◽  
Order Rate Constant ◽  
Kinetics And Mechanism ◽  
Kinetics Of Oxidation ◽  
First Order ◽  
Iron Heme ◽  
Kinetics Of

The kinetics of oxidation of zero-valent mercury by the horseradish peroxidase system are reported. The reaction is first order in mercury and first order in peroxidase compound 1, and appear to obey these kinetics to completion of the reaction. The second order rate constant is 8.58 × 105 M−1 min−1 at 23 °C. The data are consistent with a simple two-electron transfer from mercury to the iron–heme system of peroxidase with the enzyme acting as a chemical oxidant that is continually being regenerated by reaction with hydrogen peroxide.

scholarly journals Catalytic Effect of 1,4-Dioxane on the Kinetics of the Oxidation of Iodide by Dicyanobis(bipyridine)iron(III) in Water

Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 840
Author(s):  
Rozina Khattak ◽  
Muhammad Sufaid Khan ◽  
Zahoor Iqbal ◽  
Rizwan Ullah ◽  
Abbas Khan ◽  
...  
Keyword(s):  
Ionic Strength ◽  
Rate Constant ◽  
Carrier Transport ◽  
Dye Sensitized Solar Cells ◽  
Catalytic Efficiency ◽  
Spectrophotometric Analysis ◽  
Binary Solvent ◽  
Experimental Conditions ◽  
Reaction Media ◽  
Kinetics Of

Dye-sensitized solar cells (DSSCs) are a technically and financially viable alternative to today’s photovoltaic systems using p-n junctions. The two functions are isolated here, which are unlike traditional systems where the semiconductor is thought to perform both light absorption and charge carrier transport. This article discusses the potential use of dicyanobis(bipyridine)iron(III) to oxidize iodide as a sensitizer in DSSCs. However, it is critical to understand the kinetics of this essential process in order to understand the mechanism of electron transport. The oxidation of iodide by dicyanobis(bipyridine)iron(III) in three reaction media was studied: water, 10% v/v 1,4-dioxane-water, and 20% v/v 1,4-dioxane-water. The reaction was carried out in a regular laboratory setting, with no special sensitive conditions or the use of expensive materials, making it a cost-effective and practical method. Dicyanobis(bipyridine)iron(III) oxidized iodide in selected media at 0.06 M ionic strength and constant temperature. The reaction was subjected to a spectrophotometric analysis. The data were acquired by measuring the rise in visible absorbance as a function of time after the formation of dicyanobis(bipyridine)iron(II). The reaction proceeded with an overall fractional (0.5), first order, and third order in water, 10% media, and 20% media, respectively. The presence of dicyanobis(bipyridine)iron(III) in either of the reaction media had no effect on the rate. The effect of protons (H+) on the rate constant indicated resistance in water and catalysis in dioxane-water media containing 10–20% dioxane. When the ionic strength was raised, there was no change in the rate constant in water, but there was a deceleration in both binary solvent media. In an aqueous medium, the thermodynamic parameters of activation were computed as Ea 46.23 kJ mol−1, 24.62 M s−1, ΔH# 43.76 kJ mol−1, ΔS# −226.5 J mol−1 K−1, and ΔG# 111.26 kJ mol−1 (25 °C). By increasing the rate of the reaction to its maximum, this study discovered the binary solvent media with the highest catalytic efficiency, i.e., 20% v/v 1,4-dioxane-water, which may increase the efficiency of DSSCs without using any expensive material or unusual experimental conditions.

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