Solute-solute interactions and the kinetics of chemical reactions in aqueous solutions

The kinetics of oxidation of alkenes by thallic sulphate in aqueous solutions, involving the two reaction steps-the hydroxythallation and the dethallation - was studied, and the effect of salts on the kinetics was examined; this made it possible to specify more precisely the reaction mechanism and to suggest a qualitative model of the reaction coordinate. It was found that in homogeneous as well as in heterogeneous reaction conditions, the reaction can be accelerated appreciably by adding tetraalkylammonium salts. These salts not only operate as catalysts of the phase transfer, but also exert a significant kinetic effect, which can be explained with a simplification in terms of a stabilization of the transition state of the reaction.

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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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Preparation and Evaluation of Skeletal Cobalt-Molybdenum Hydrodesulfurization Catalysts

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19950568 ◽

1995 ◽

Vol 60 (4) ◽

pp. 568-575

Author(s):

Karel Sporka ◽

Jiří Hanika ◽

Vladimír Jůn

Keyword(s):

Aqueous Solutions ◽

Active Component ◽

Catalyst Activity ◽

Gas Oil ◽

Gamma Alumina ◽

Molybdenum Sulfides ◽

Hydrodesulfurization Catalysts ◽

Hds Catalysts ◽

Kinetics Of ◽

Preparation And Evaluation

Preparation of skeletal Co-Mo catalysts by controlled impregnation of aluminosilicate skeletons containing deposited gamma-alumina with aqueous solutions of active component precursors has been investigated. The activity of the laboratory catalysts in gas oil hydrodesulfurization has been determined. Kinetics of impregnation of skeletal supports, the effect of their type, and the dependence of catalyst activity on the content of cobalt and molybdenum sulfides are reported. HDS skeletal catalysts prepared were compared with the extruded types. It was found that skeletal HDS catalysts show the higher activity (related to the content of alumina and Co-Mo sulfides) than the extruded ones due to the less significant effect of internal diffusion. However, if the activity is related to the same volume of catalyst bed, the activity of skeletal catalysts is only one fourth of that of the extruded types.

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Study of potential oscillations during reaction of an aluminium single crystal with an aqueous KOH solution

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19900345 ◽

1990 ◽

Vol 55 (2) ◽

pp. 345-353 ◽

Cited By ~ 4

Author(s):

Ivan Halaša ◽

Milica Miadoková

Keyword(s):

Aqueous Solutions ◽

Single Crystal ◽

Single Crystals ◽

Periodic Potential ◽

Optimum Conditions ◽

Potential Oscillations ◽

Dilute Aqueous Solutions ◽

Experimental Findings ◽

Kinetics Of

The authors investigated periodic potential changes measured on oriented sections of Al single crystals during spontaneous dissolution in dilute aqueous solutions of KOH, with the aim to find optimum conditions for the formation of potential oscillations. It was found that this phenomenon is related with the kinetics of the reaction investigated, whose rate also changed periodically. The mechanism of the oscillations is discussed in view of the experimental findings.

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