The correlation of the overall rate constant to the dose intensity in the kinetic equation for radio-oxidation of cystine in aqueous solutions

1967 ◽  
Vol 32 (8) ◽  
pp. 3024-3028
Author(s):  
R. Brdička ◽  
A. Fojtík
Keyword(s):  
Kinetic Equation ◽  
Aqueous Solutions ◽  
Rate Constant ◽  
Dose Intensity

scholarly journals Kinetics of thiamin cleavage by sulphite

1969 ◽  
Vol 113 (4) ◽  
pp. 611-615 ◽  
Author(s):  
J. Leichter ◽  
M. A. Joslyn
Keyword(s):  
Aqueous Solutions ◽  
Rate Constant ◽  
Sulphur Dioxide ◽  
First Order ◽  
Ph Values ◽  
Rate Of Reaction ◽  
Kinetics Of

Results are presented on the rate of thiamin cleavage by sulphite in aqueous solutions as affected by temperature (20–70°), pH(2·5–7·0), and variation of the concentration of either thiamin (1–20μm) or sulphite (10–5000μm as sulphur dioxide). Plots of the logarithm of percentage of residual thiamin against time were found to be linear and cleavage thus was first-order with respect to thiamin. At pH5 the rate was also found to be proportional to the sulphite concentration. In the pH region 2·5–7·0 at 25° the rate constant was 50m−1hr.−1 at pH5·5–6·0, and decreased at higher or lower pH values. The rate of reaction increased between 20° and 70°, indicating a heat of activation of 13·6kcal./mole.

Kinetics and mechanism of destruction of cobalt phthalocyanine derivatives in aqueous solutions

2000 ◽  
Vol 04 (07) ◽  
pp. 684-688 ◽  
Author(s):  
S. A. BORISENKOVA ◽  
E. P. DENISOVA ◽  
E. A. BATANOVA ◽  
E. G. GIRENKO ◽  
O. L. KALIYA ◽  
...  
Keyword(s):  
Kinetic Equation ◽  
Aqueous Solutions ◽  
Partial Pressure ◽  
Initial Solution ◽  
Cobalt Phthalocyanine ◽  
Oxidative Destruction ◽  
Partial Pressure Of Oxygen ◽  
Concentration Interval ◽  
Kinetics Of ◽  
Bleaching Rate

The kinetics of the oxidative destruction of cobalt phthalocyanine derivatives in aqueous solutions has been investigated in the concentration interval 10−4–10−5 M as a function of the concentration of alkali and the partial pressure of oxygen in the system. The kinetic equation for the initial solution bleaching rate is obtained. A mechanism of cobalt phthalocyanine destruction involving an intermediate Co (II) → Co (III) oxidation step is suggested.

Conductometric Pulse Radiolysis Study on the Reaction of the Solvated Electron with 5-Bromouracil in Aqueous Solutions at Different pH Values

1974 ◽  
Vol 29 (1-2) ◽  
pp. 86-88b ◽  
Author(s):  
Burkhard O. Wagner ◽  
Herbert Klever ◽  
Dietrich Schulte-Frohlinde
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Atom ◽  
Aqueous Solutions ◽  
Hydroxyl Radical ◽  
Rate Constant ◽  
Pulse Radiolysis ◽  
Solvated Electron ◽  
Ph Values

To study the reaction of the solvated electron with 5-bromouracil an aqueous solution has been examined by conductometric pulse radiolysis at pH values between 4.68 and 8.74. Alcohol was added to scavenge the hydrogen atom and the hydroxyl radical. G(Br—) = (2.64 ± 0.08)/100 eV was found to be independent of the pH. The mobility of the bromouracil mono-anion was measured to be (2.7 ± 0.2) 10-4 cm2 V-1 s-1 at 20°C, and the rate constant of reaction (3b) was determined to be k(H+ BrUr-) = (2.3 ± 0.2) 1010 I mole-1 s-1*.

The pH Dependence of the Ruthenium-Catalyzed Ferricyanide Oxidation of Cyclohexanol

1989 ◽  
Vol 42 (8) ◽  
pp. 1273 ◽  
Author(s):  
RW Kaziro ◽  
JK Beattie
Keyword(s):  
Aqueous Solutions ◽  
Rate Constant ◽  
Ph Dependence ◽  
Catalytic Cycle ◽  
Ph Range ◽  
Catalyst Lifetime ◽  
Reduced State

The oxidation of cyclohexanol to cyclohexanone by ferricyanide in alkaline aqueous solutions is catalysed by the addition of chlororuthenium compounds. In solutions of pH less than 11 the progress of the reaction is limited by the decomposition of the catalyst in its reduced state. The catalyst lifetime can be lengthened by an increase in the concentration of the ferricyanide oxidant. In solutions of pH 11.3-11.9 either of the oxidation or the reduction steps of the catalytic cycle can be made rate determining, by adjustment of the relative concentrations of cyclohexanol and ferricyanide . The decrease in rate with increase in pH is due to the pH dependence of the reaction of the oxidized catalyst. The rate constant decreases from 26 to 15 dm3 mol-1 s-l between pH 11.3 and 11.9. The rate constant for the ferricyanide oxidation of the reduced catalyst is pH-independent at (6 � 2)×102 dm3 mol-1 s-1 at 298 K, over the same pH range.

scholarly journals Kinetics of gibbsite leaching in sodium hydroxide aqueous solution

2002 ◽  
Vol 56 (9) ◽  
pp. 381-385
Author(s):  
Ljubica Pavlovic ◽  
Zagorka Acimovic-Pavlovic ◽  
Ljubisa Andric ◽  
Aurel Prstic
Keyword(s):  
Activation Energy ◽  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Sodium Hydroxide ◽  
Kinetic Parameters ◽  
Rate Constant ◽  
Reaction Rate ◽  
Reaction Rate Constant ◽  
Kinetics Of ◽  
Mechanism Of The Reaction

In order to study the kinetics and mechanism of the reaction, laboratory leaching was carried out with industrially produced gibbsite ?-Al(OH)3 in aqueous solutions containing an excess of sodium hydroxide. The results obtained reaction temperature, duration and base concentration varied. The basic kinetic parameters were determined from: the reaction rate constant k=8.72?107 exp (-74990/RT) and the process activation energy in the range Ea=72.5-96.81 kJ/mol.

Temperature-dependence of electrochemical kinetic parameters: Electrode reaction of the Zn(Hg)/Zn(II) system

1982 ◽  
Vol 47 (5) ◽  
pp. 1433-1443 ◽  
Author(s):  
S. Kang ◽  
K. Matsuda ◽  
R. Tamamushi
Keyword(s):  
Aqueous Solutions ◽  
Temperature Dependence ◽  
Kinetic Parameters ◽  
Rate Constant ◽  
Activation Parameters ◽  
Electrode Reaction ◽  
Thermodynamic Quantities ◽  
Empirical Correlations ◽  
Square Wave ◽  
Different Temperatures

The electrochemical kinetic parameters of the D.M.E./Zn(II) electrode reaction in aqueous solutions containing perchlorate, nitrate, chloride and bromide ions were measured at different temperatures (5-50 °C) by the modified square-wave polarographic technique. The Arrhenius activation parameters and thermodynamic quantities of the electrode reaction were determined from the temperature dependence of the rate constant and conditional potential, respectively. Empirical correlations were observed between some pairs of kinetic and thermodynamic quantities.

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