The Influence of N,N'-Dialkylthioureas on the Two-Step Electroreduction of Zn(II) Ions

1998 ◽  
Vol 63 (6) ◽  
pp. 749-760 ◽  
Author(s):  
Grażyna Dalmata
Keyword(s):  
Electron Transfer ◽  
Double Layer ◽  
Rate Constant ◽  
Electrode Surface ◽  
Mercury Electrode ◽  
Impedance Method ◽  
Dropping Mercury Electrode ◽  
Wide Potential ◽  
Orientation Of Molecules

A two-step reduction of Zn(II) ions at the dropping mercury electrode in 1 M NaClO4/0.001 M HClO4 in the presence of N,N'-dialkylthioureas was examined in wide potential and frequency ranges, using the impedance method. The rate constant of the first electron transfer increases with increasing concentration of N,N'-dialkylthioureas, whereas that of the second electron transfer depends largely on the double layer effects, particularly, on the orientation of molecules on the electrode surface.

The Effect of p-Toluidine on the Two-Step Electroreduction of Zn(II) in Water-Methanol and Water-Dimethylformamide

1999 ◽  
Vol 64 (4) ◽  
pp. 585-594 ◽  
Author(s):  
Barbara Marczewska
Keyword(s):  
Electron Transfer ◽  
Binary Mixtures ◽  
Rate Constant ◽  
Rate Constants ◽  
Electrode Surface ◽  
Mercury Electrode ◽  
Forward Rate ◽  
Solvent Molecules ◽  
Activated Complex

The acceleration effect of p-toluidine on the electroreduction of Zn(II) on the mercury electrode surface in binary mixtures water-methanol and water-dimethylformamide is discussed. The obtained apparent and true forward rate constants of Zn(II) reduction indicate that the rate constant of the first electron transfer increases in the presence of p-toluidine. The acceleration effect may probably be accounted for by the concept of the formation on the mercury electrode an activated complex, presumably composed of p-toluidine and solvent molecules.

Reduction of the Ni(II) ion at the dropping mercury electrode from amoxicillin water solution

1991 ◽  
Vol 56 (1) ◽  
pp. 152-156 ◽  
Author(s):  
Milenko R. Erceg ◽  
Vera P. Kapetanović ◽  
Desanka Ž. Sužnjević
Keyword(s):  
Complex Formation ◽  
Double Layer ◽  
Rate Constant ◽  
Electrical Double Layer ◽  
Water Solution ◽  
Mercury Electrode ◽  
Reduction Mechanism ◽  
Dropping Mercury Electrode ◽  
Heterogenous Reaction

The nature of polarographic precurrents of Ni(II) ion in the presence of amoxicillin as well as the behaviour of amoxicillin in the electrical double layer has been investigated. It has been established the formation of the mono complex of Ni(II) ion with amoxicillin adsorbed at the mercury. The reduction mechanism of the complex has been proposed. Taking into account the effect of the double layer on the kinetics, the rate constant of the heterogenous reaction of the complex formation has been found to be 5.8 · 103 l mol-1 s -1.

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