Influence of Nitrogen-Containing Bases on the Rate of the Electrode Processes at the Dropping Mercury Electrode

Nature ◽  
1960 ◽  
Vol 185 (4715) ◽  
pp. 743-745 ◽  
Author(s):  
V. VOLKOVÁ
Keyword(s):  
Mercury Electrode ◽  
Electrode Processes ◽  
Dropping Mercury Electrode

Polarography of azobenzene and its p-sulphonic acids

1964 ◽  
Vol 17 (10) ◽  
pp. 1085 ◽  
Author(s):  
TM Florence ◽  
YJ Farrar
Keyword(s):  
Ph Effect ◽  
Aqueous Media ◽  
Mercury Electrode ◽  
Electrode Reaction ◽  
Ammonium Ions ◽  
Current Time ◽  
Electrode Processes ◽  
Ph Values ◽  
Strong Adsorption ◽  
Dropping Mercury Electrode

The behaviour at the dropping mercury electrode of trans-azobenzene and its p-sulphonic acids has been studied by several techniques including d.c., a.c., single sweep, and Kalousek polarography. Current-potential curves recorded at the streaming mercury electrode provided information on the reversibility of the electrode processes, while current-time and electrocapillary curves aided in elucidating the effects of adsorption. The results show that the rate of the electrode reaction of the azo-hydrazo couple is dependent on pH, the minimum rate occurring near pH 9 for azobenzene-4-sulphonic acid in aqueous media. At very low and high pH values, the couple approaches full reversibility at the dropping mercury electrode. This pH effect is apparently due to strong adsorption of both the azo and hydrazo derivatives near the potential of the electrocapillary maximum. Ammonium ions associate with azobenzene-4-sulphonate, and improve the reversibility in intermediate pH regions.

Adsorption of Triphenyl Phosphine Oxide at the Dropping Mercury Electrode in Methanolic Solutions

1972 ◽  
Vol 27 (6) ◽  
pp. 634-636 ◽  
Author(s):  
S. L. Gupta ◽  
L. Holleck
Keyword(s):  
Phosphine Oxide ◽  
Mercury Electrode ◽  
Potential Range ◽  
Desorption Peak ◽  
Triphenyl Phosphine ◽  
Strong Inhibitor ◽  
Adsorption Activity ◽  
Electrode Processes ◽  
Dropping Mercury Electrode ◽  
Triphenyl Phosphine Oxide

Triphenyl Phosphine Oxide (TPO) which is known as a strong inhibitor of electrode processes in aqueous solutions is progressively adsorbed at the dme from methanol in the potential range -0.5 to -1.3 volts as compared with water, -0.15 to -1.6 volts (Ag/AgCl), for the concentrations studied. Adsorption activity as well as the sharpness of the desorption peak of TPO decrease in the order: water > 50% methanol > methanol and the adsorption region contracts as the solvent is changed from water to methanol. Adsorption isotherms in methanol and 50% methanol follow Langmuir's equation with adsorption coefficients equal to 1.58 x 102 l/mole and 1.62 x 104 l/mole respectively.

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