Kinetics of the alkaline ferricyanide-thiocyanate reaction

1979 ◽  
Vol 12 (2) ◽  
pp. 195-197 ◽  
Author(s):  
Suseela B. Sant
Keyword(s):  
Alkaline Ferricyanide ◽  
Kinetics Of

Kinetics and Mechanism of Os(VIII) Catalysed Oxidation of Mandelate Ion by Alkaline Ferricyanide

1972 ◽  
Vol 27 (8) ◽  
pp. 908-910 ◽  
Author(s):  
G. C. Soni ◽  
G. D. Menghani
Keyword(s):  
Mandelic Acid ◽  
Kinetics And Mechanism ◽  
Acid Anion ◽  
Catalysed Oxidation ◽  
Hydroxyl Ion ◽  
Anion Complex ◽  
Mechanism Of Oxidation ◽  
Alkaline Ferricyanide ◽  
Kinetics Of

The kinetics of the reaction between alkaline ferricyanide and mandelic acid catalysed by [Os (VIII) ] has beeen studied. The rate of ferricyanide disappearance was found to be proportional to the concentration of mandelate ion and Os (VIII), but independent of the concentration of ferricyanide. Within a limited concentration range of hydroxyl ion [ [OH-1] < 0.25 M] the rate varies directly as the [OH⁻]. Effects of SO4-2, ΝO3-1NO3-1 and temperature on the rate were studied. ΔΕ, PZ, AS* etc. were evaluated. Mechanism of oxidation of mandelic acid based on the formation of Os (VIII) acid anion complex is suggested.

Oxidation of Hydrazine by Alkaline Ferricyanide in Water-methanol Mixtures

1970 ◽  
Vol 25 (2) ◽  
pp. 188-190 ◽  
Author(s):  
V. K. Jindal ◽  
M. C. Agrawal ◽  
S. P. Mushran
Keyword(s):  
Ion Concentration ◽  
Hydroxide Ion ◽  
First Order ◽  
Order Dependence ◽  
Buffer Solutions ◽  
Entropy Of Activation ◽  
Alkaline Ferricyanide ◽  
Specific Ion Effect ◽  
Kinetics Of

Kinetics of the oxidation of hydrazine by ferricyanide was investigated in water-methanol mixtures using several buffer solutions. The reaction showed first order dependence in both hydrazine and ferricyanide. The order with respect to hydroxide ion concentration was zero. Increase in concentration of methanol had a retarding influence on the rate while the addition of neutral salts showed a specific ion effect. The energy and entropy of activation were calculated as 12.3 kcals. mole-1 and -20.8 cals. deg-1 mole-1 respectively. A suitable mechanism has been proposed which suggests the primary rate determining reaction between N2H4 and Fe (CN)63⊖. Nitrogen was found to be the product of the reaction.

Direct observations of radiation-enhanced transformations in glass

1983 ◽  
Vol 41 ◽  
pp. 354-355
Author(s):  
J. F. DeNatale ◽  
D. G. Howitt
Keyword(s):  
Glass Matrix ◽  
Diffusion Mechanism ◽  
Bubble Formation ◽  
Silicate Glasses ◽  
Phase Decomposition ◽  
Direct Observations ◽  
Thin Foils ◽  
Oxygen Bubble ◽  
Electron Energy Loss ◽  
Kinetics Of

The electron irradiation of silicate glasses containing metal cations produces various types of phase separation and decomposition which includes oxygen bubble formation at intermediate temperatures figure I. The kinetics of bubble formation are too rapid to be accounted for by oxygen diffusion but the behavior is consistent with a cation diffusion mechanism if the amount of oxygen in the bubble is not significantly different from that in the same volume of silicate glass. The formation of oxygen bubbles is often accompanied by precipitation of crystalline phases and/or amorphous phase decomposition in the regions between the bubbles and the detection of differences in oxygen concentration between the bubble and matrix by electron energy loss spectroscopy cannot be discerned (figure 2) even when the bubble occupies the majority of the foil depth.The oxygen bubbles are stable, even in the thin foils, months after irradiation and if van der Waals behavior of the interior gas is assumed an oxygen pressure of about 4000 atmospheres must be sustained for a 100 bubble if the surface tension with the glass matrix is to balance against it at intermediate temperatures.

Irradiation behavior of pyrolytic silicon carbide

1983 ◽  
Vol 41 ◽  
pp. 72-73
Author(s):  
R. J. Lauf
Keyword(s):  
Silicon Carbide ◽  
Fission Products ◽  
Thermodynamics And Kinetics ◽  
Neutron Fluences ◽  
Fuel Particles ◽  
Sic Coatings ◽  
Irradiation Behavior ◽  
Kinetics Of ◽  
Htgr Fuel

Fuel particles for the High-Temperature Gas-Cooled Reactor (HTGR) contain a layer of pyrolytic silicon carbide to act as a miniature pressure vessel and primary fission product barrier. Optimization of the SiC with respect to fuel performance involves four areas of study: (a) characterization of as-deposited SiC coatings; (b) thermodynamics and kinetics of chemical reactions between SiC and fission products; (c) irradiation behavior of SiC in the absence of fission products; and (d) combined effects of irradiation and fission products. This paper reports the behavior of SiC deposited on inert microspheres and irradiated to fast neutron fluences typical of HTGR fuel at end-of-life.

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