ChemInform Abstract: ON THE APPLICATION OF OPEN CIRCUIT RELAXATION SPECTROELECTROCHEMISTRY TO THE DIAGNOSIS AND EVALUATION OF THE KINETICS OF SUCCEEDING SECOND ORDER CHEMICAL REACTIONS

AbstractWe have observed a significant light-induced increase in the open-circuit voltage (Voc) of mixed-phase hydrogenated silicon solar cells. In this study, we investigate the kinetics of the light-induced effects. The results show that the cells with different initial Voc have different kinetic behavior. For the cells with a low initial Voc (less than 0.8 V), the increase in Voc is slow and does not saturate for light-soaking time of up to 16 hours. For the cells with medium initial Voc (0.8 ∼ 0.95 V), the Voc increases rapidly and then saturates. Cells with high initial Voc (0.95 ∼ 0.98 V) show an initial increase in Voc, followed bya Voc decrease. All light-soaked cells exhibit a degradation in fill factor. The temperature dependence of the kinetics shows that light soaking at high temperatures causes Voc increase to saturate faster than at low temperatures. The observed results can be explained by our recently proposed two-diode equivalent-circuit model for mixed-phase solar cells.

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Spectrocoulometry – a new spectro-electrochemical technique

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19871386 ◽

1987 ◽

Vol 52 (6) ◽

pp. 1386-1396 ◽

Cited By ~ 3

Author(s):

Ján Mocák ◽

Michal Németh ◽

Mieczyslaw Lapkowski ◽

Jerzy W. Strojek

Keyword(s):

Optical Probe ◽

Optical Signal ◽

Open Circuit ◽

Electrochemical Technique ◽

Kinetics Of Oxidation ◽

Hydrolytic Reaction ◽

Experimental Errors ◽

Mechanism And Kinetics ◽

Kinetics Of

A spectrocoulometric macrocell with a direct-view optical probe was designed and constructed, where the optical signal is transferred by light-conducting glass or quartz fibres permitting to work at wavelengths above 410 or 300 nm. The method of measurement on the proposed equipment is described; it was tested in the study of the mechanism and kinetics of oxidation of Fe(bipy)32+ ions (bipy = 2,2'-bipyridyl) with the use of potentiostatic coulometric electrolysis with open-circuit relaxation at a suitable time. The primary product of electrolysis, Fe(bipy)33+, undergoes a follow-up hydrolytic reaction with the formation of a binuclear complex. The rate constant of the reaction of the first order involves the contributions, kBi, from all bases present in solution; the corresponding values for H2O, OH-, bipy, and CH3COO- ions at a ionic strength 0·5 mol dm-3 and 25 °C were determined as kOH = (5·0 ± 0·6) . 105 mol-1 dm3 s-1, kbipy = (1·3 ± 0·2) . 10-1 mol-1 dm3 s-1, kAc = (5·8 ± 1·0) . 10-2 mol-1 dm3 s-1, and kH2O is not significant with respect to experimental errors.

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New highly efficient coulometric cell with homogenous potential distribution on the working electrode

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19860636 ◽

1986 ◽

Vol 51 (3) ◽

pp. 636-642

Author(s):

Michal Németh ◽

Ján Mocák

Keyword(s):

Chemical Reactions ◽

Potential Distribution ◽

Anaerobic Conditions ◽

Highly Efficient ◽

Working Electrode ◽

Constant Potential ◽

Quantitative Analyses ◽

Mechanism And Kinetics ◽

Kinetics Of

A highly efficient coulometric cell was designed and constructed, ensuring a constant potential over the whole surface of the working electrode and suitable for very rapid electrolysis. It consists of concentric cylindrical Teflon parts; also the working and auxiliary electrodes are cylindrical and concentric. Electrolysis can be carried out under anaerobic conditions. Functioning of the cell was tested on the oxidation of hexacyanoferrate(II) and chlorpromazine and reduction of hexacyanoferrate(III). The new cell is suitable for routine quantitative analyses and in studying the mechanism and kinetics of moderately rapid chemical reactions.

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Kinetics of the reaction between hexamethylenediisocyanate and 1-pentanol

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19833279 ◽

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.

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Evidence for general base catalysis by protic solvents in a kinetic study of alcoholyses and hydrolyses of 1-(phenoxycarbonyl)pyridinium ions under both solvolytic and non-solvolytic conditions

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc2008164 ◽

2009 ◽

Vol 74 (1) ◽

pp. 43-55 ◽

Cited By ~ 1

Author(s):

Dennis N. Kevill ◽

Byoung-Chun Park ◽

Jin Burm Kyong

Keyword(s):

Second Order ◽

Base Catalysis ◽

Substitution Reactions ◽

Third Order ◽

Methoxy Derivative ◽

First Order ◽

General Base ◽

Protic Solvents ◽

Kinetics Of ◽

Pyridinium Ions

The kinetics of nucleophilic substitution reactions of 1-(phenoxycarbonyl)pyridinium ions, prepared with the essentially non-nucleophilic/non-basic fluoroborate as the counterion, have been studied using up to 1.60 M methanol in acetonitrile as solvent and under solvolytic conditions in 2,2,2-trifluoroethan-1-ol (TFE) and its mixtures with water. Under the non- solvolytic conditions, the parent and three pyridine-ring-substituted derivatives were studied. Both second-order (first-order in methanol) and third-order (second-order in methanol) kinetic contributions were observed. In the solvolysis studies, since solvent ionizing power values were almost constant over the range of aqueous TFE studied, a Grunwald–Winstein equation treatment of the specific rates of solvolysis for the parent and the 4-methoxy derivative could be carried out in terms of variations in solvent nucleophilicity, and an appreciable sensitivity to changes in solvent nucleophilicity was found.

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Determination of the Nucleophilicity of Tricarbonyliron Coordinated Cyclohepta-1,3,5-triene

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19991770 ◽

1999 ◽

Vol 64 (11) ◽

pp. 1770-1779 ◽

Cited By ~ 6

Author(s):

Herbert Mayr ◽

Karl-Heinz Müller

Keyword(s):

Gibbs Energy ◽

Ambient Temperature ◽

Rate Constants ◽

Second Order ◽

Order Rate ◽

Electrophilic Additions ◽

Kinetics Of

The kinetics of the electrophilic additions of four diarylcarbenium ions (4a-4d) to tricarbonyl(η4-cyclohepta-1,3,5-triene)iron (1) have been studied photometrically. The second-order rate constants match the linear Gibbs energy relationship log k20 °C = s(E + N) and yield the nucleophilicity parameter N(1) = 3.69. It is concluded that electrophiles with E ≥ -9 will react with complex 1 at ambient temperature.

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Kinetics and mechanism of oxidation of DL-α-alanine by permanganate ion in acid perchlorate media

Canadian Journal of Chemistry ◽

10.1139/v91-292 ◽

1991 ◽

Vol 69 (12) ◽

pp. 2018-2023 ◽

Cited By ~ 30

Author(s):

Refat M. Hassan

Keyword(s):

Amino Acids ◽

Ionic Strength ◽

Acid Solution ◽

Second Order ◽

Perchloric Acid Solution ◽

Oxidation Reduction ◽

Initial Stage ◽

Aqueous Perchloric Acid ◽

Mechanism Of Oxidation ◽

Kinetics Of

The kinetics of permanganate oxidation of DL-α-alanine in aqueous perchloric acid solution at a constant ionic strength of 2.0 mol dm−3 has been investigated spectrophotometrically. The reaction was found to show second-order kinetics overall with respect to each of the reactants in the slow initial stage; the second-order kinetics are not, however, maintained throughout the relatively fast final stage of reaction. The added salts lead to the prediction that Mn(III) and (or) Mn(IV) play a very important role in the reaction kinetics. A tentative mechanism consistent with the kinetics is discussed. Key words: kinetics, oxidation, reduction, amino acids, permanganate.

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