ChemInform Abstract: STUDIES ON BIS(AZO) COMPOUNDS. II. POLAROGRAPHIC BEHAVIOR OF 1-(4-(4-SODIUM SULFONATOPHENYLAZO)-3-SODIUM SULFONATOPHENYLAZO)-2-NAPHTHOL IN SOLUTIONS OF VARYING PH AT THE DROPPING MERCURY ELECTRODE

1979 ◽  
Vol 10 (20) ◽  
Author(s):  
Y. M. TEMERK
Keyword(s):  
Mercury Electrode ◽  
Azo Compounds ◽  
Polarographic Behavior ◽  
Dropping Mercury Electrode

Polarography of aromatic azo compounds. II. Kinetic study of the disproportionation of 4-Aminohydrazobenzene-4'-sulphonic acid

1965 ◽  
Vol 18 (5) ◽  
pp. 619 ◽  
Author(s):  
TM Florence
Keyword(s):  
Mercury Electrode ◽  
Sulphonic Acid ◽  
Azo Compounds ◽  
Rate Determining Step ◽  
A Value ◽  
Controlled Potential Electrolysis ◽  
Mercury Cathode ◽  
Dropping Mercury Electrode ◽  
Controlled Potential ◽  
Aromatic Azo Compounds

Solutions of 4-aminoazobenzene-4'-sulphonic acid were reduced by controlled potential electrolysis at a mercury cathode, and the disproportionation rate of the hydrazo derivative determined by spectrophotometry and polarography. The kinetics of the reaction were found to be first-order with respect to both hydrazo and hydrogen ion concentrations, although the overall reaction involved two molecules of the hydrazo compound. In the rate law, -d[hydrazo]/dt = k[H+][hydrazo], k was calculated to be (5.0�0.3) x 106 l. mole-1 sec-1 from spectrophotometric measurements, and (4.5�0.5) x 106 l. mole-1 sec-1 by polarography (25�). A reaction mechanism based on a rate determining step involving a quinonediimine intermediate has been proposed. Another value of the disproportionation rate constant was obtained from the effect of drop time on the limiting currents of 4-aminoazobenzene-4'-sulphonic acid at the dropping mercury electrode. A value of k of (22�5) x 106 l. mole-1 sec-1 was determined by this method. Reasons for the discrepancy between this result, and those found by direct measurement, are discussed.

POLAROGRAPHIC BEHAVIOR OF THE VIOLOGEN INDICATORS

1957 ◽  
Vol 35 (7) ◽  
pp. 646-650 ◽  
Author(s):  
R. M. Elofson ◽  
R. L. Edsberg
Keyword(s):  
Methyl Viologen ◽  
Mercury Electrode ◽  
Single Electron ◽  
Second Step ◽  
Polarographic Behavior ◽  
Benzyl Viologen ◽  
Dropping Mercury Electrode ◽  
Ph Range ◽  
Reversible Reduction

The polarographic behavior of 1,1′-dimethyl- and 1,1′-dibenzyl-4,4′-bipyridinium dichloride has been investigated over the pH range of 1 to 13. Reversible reduction waves are obtained for the first single-electron step for both compounds. The second step is electrochemically irreversible but evidence is presented to indicate that the second step is fleetingly reversible at the dropping mercury electrode for methyl viologen but not benzyl viologen. Minor waves due to adsorption of the reduced viologen on the surface of the mercury have been observed.

Sign in / Sign up

Export Citation Format

Share Document