Polarographic reduction of phenolphthalein, cresolphthalein, thymolphthalein, and α-naphtholphthalein in aqueous and nonaqueous ethanolic solutions

1979 ◽  
Vol 57 (11) ◽  
pp. 1294-1298 ◽  
Author(s):  
Mohamed M. Ghoneim ◽  
Mohamed A. A. Ashy
Keyword(s):  
Kinetic Parameters ◽  
Aqueous Medium ◽  
Electrode Reaction ◽  
Polarographic Reduction ◽  
The Waves

The polarographic reduction of phenolphthalein, cresolphthalein, thymolphthalein, and α-naphtholphthalein has been studied in ethanolic Britton–Robinson buffer series (pH 2–12), non-aqueous ethanolic medium, and water–ethanol mixtures. The compounds are reduced through a single 2e− wave in non-aqueous medium and aqueous buffered solutions of pH < 9 or 1e− steps for pH > 9. The nature of the waves, mechanism of the electrode reaction, and kinetic parameters has been considered.

Kinetic parameters of the electrode reaction of chloropenta-amminecobalt(III) ions at a gold electrode

1983 ◽  
Vol 28 (8) ◽  
pp. 1037-1040 ◽  
Author(s):  
Shigeo Shibata ◽  
Masae Sumino ◽  
Akifumi Yamada ◽  
Tadatsugu Yoshikuni
Keyword(s):  
Kinetic Parameters ◽  
Gold Electrode ◽  
Electrode Reaction

Physical characteristics and polarographic reduction mechanism of some oxazolones

1991 ◽  
Vol 69 (12) ◽  
pp. 1886-1892 ◽  
Author(s):  
M. I. Ismail
Keyword(s):  
Redox Potential ◽  
Coulomb Repulsion ◽  
Electrode Reaction ◽  
Alkaline Media ◽  
Third Wave ◽  
Polarographic Reduction ◽  
Buffer Solutions ◽  
Rate Of Hydrolysis ◽  
Hydrolysis Of ◽  
Electronic Transition Energy

The redox potential (ΔE1/2), electron affinity (EA), ionization potential (IP), coulomb repulsion integral (J12), and electronic transition energy (ECT) of several oxazolone derivatives in DMF were computed. A linear correlation was shown to exist between ΔE1/2 and ECT• The polarographic reduction was investigated in ethanolic-Theil buffer solutions. At pH ≤ 7.2, two waves were obtained representing the uptake of 2- and 4-electron steps respectively. In alkaline media, a third wave appeared seemingly a result of the hydrolysis of oxazolones. The rate of hydrolysis was determined and the electrode mechanism was elucidated and confirmed via spectrophotometric and coulometric analysis. Key words: oxazolones, polarography, electrochemistry, electrode reaction, spectrophotometry, redox potential.

Polarographic Study of the Electrode Reaction of Zn(II) in Formamide and Dimethylformamide

1975 ◽  
Vol 30 (5-6) ◽  
pp. 350-354 ◽  
Author(s):  
Sudhindra Swarup Sharma ◽  
Mukhtar Singh
Keyword(s):  
Kinetic Parameters ◽  
Organic Solvents ◽  
Metal Ion ◽  
Supporting Electrolyte ◽  
Electrode Reaction ◽  
Polarographic Study ◽  
Aqueous Mixtures ◽  
Diffusion Controlled ◽  
And Diffusion

The reduction of Zn(II) at the d.m.e. has been studied in aqueous mixtures of formamide and dimethylformamide. The general polarographic characteristics have been determined, using 0.1 M NaNO3 as the supporting electrolyte. The reduction of Zn(II) in these organic solvents is irreversible and diffusion controlled. The kinetic parameters, αna and kf,h have been calculated separately by KOTECKY and DELAHAY treatments. The change of polarographic characteristics and kinetic parameters is explained in terms of solvation of the metal ion in these solvents. The electrocapillary curves in the presence of these solvents have also been studied.

scholarly journals A cyclic voltammetric study of the influence of supporting electrolytes on the redox behaviour of Cu(II) in aqueous medium

1970 ◽  
Vol 24 (2) ◽  
pp. 158-164 ◽  
Author(s):  
Aftab Ali Shaikh ◽  
M Badrunnessa ◽  
Jannatul Firdaws ◽  
Md Shahidur Rahman ◽  
Nishat Ahmed Pasha ◽  
...  
Keyword(s):  
Aqueous Medium ◽  
Electrochemical Reaction ◽  
Supporting Electrolyte ◽  
Electrode Reaction ◽  
Chemical Society ◽  
Reduction Peak ◽  
Hydrogen Bridge ◽  
Peak Current ◽  
Bridge Bond ◽  
Electrochemical Redox

The electrochemical redox behavior of Cu(II) has been investigated at glassy carbon electrode (GCE) in Britton-Robinson (BR) buffer as well as in a mixture of BR buffer and potassium chloride media. It is apparent that BR buffer can act as a supporting electrolyte and modify the electrochemical behavior of Cu(II) ion in aqueous medium. In BR buffer medium, Cu(II) undergoes one two-electrons redox process, while in a mixture of BR buffer and KCl media it follows two one-electron electrochemical reaction routes. Because of the formation of hydrogen bridge bond between the supporting electrolyte and GCE surface, the Cu(II) ion follows Cu(II)/Cu(0) electrochemical reaction path, while in presence of KCl such a hydrogen bridge bond is not formed and it undergoes successive Cu(II)/Cu(I) and Cu(I)/Cu(0) electrode reaction processes. Moreover, the linear variation of peak current with the square root of scan rate indicates that the electrochemical redox processes are diffusion controlled. Keywords: Supporting electrolytes; Britton-Robinson buffer; Cu-reduction; Peak current DOI: http://dx.doi.org/10.3329/jbcs.v24i2.9704 Journal of Bangladesh Chemical Society, Vol. 24(2), 158-164, 2011

Polarographic and Cyclic Voltammetric Behaviour of Some Azo Compounds Derived from Sulfonamide in DMF-Aqueous Solutions

1992 ◽  
Vol 57 (2) ◽  
pp. 268-275 ◽  
Author(s):  
El-Sayed M. Mabrouk ◽  
Hamada M. Killa ◽  
Abdel Fattah A. Abdel Fattah ◽  
Shalaby A. Yasen
Keyword(s):  
Reaction Mechanism ◽  
Aqueous Solutions ◽  
Kinetic Parameters ◽  
Alkaline Solution ◽  
Electrode Reaction ◽  
Azo Compounds ◽  
Cyclic Voltammetric ◽  
Ph Range

The polarographic and cyclic voltammetric behaviour of (2-hydroxyphenylazo)-4-benzenesulfonamide and some of its derivatives have been studied in Britton-Robinson buffer series containing 30 vol.% of DMF. Over the entire pH range (2-12), the reduction pathway occurs through an irreversible 4-electron step corresponding to the reduction of N=N center to the amine stage. The voltammograms recorded in acidic and alkaline solution at different scan rates exhibit one or two cathodic peaks depending on the substituent and the pH of the medium. The electrode reaction mechanism was suggested, also the kinetic parameters were calculated.

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