Reduction of azo-compounds—I. Polarographic behaviour of some 4-hydroxymonoazo compounds at the dropping mercury electrode

Electrochemical reduction of disperse orange 1 textile dye at a boron-doped diamond electrode

“…It is known that reduction of aromatic azo compounds, involving breakage of the N-N bond, is difficult in neutral media [42]. The cleavage of the azo group should be a four-electron process, while a reduction to a hydrazo compound should involve only two electrons.…”

Electrochemical Behavior of 2′-Halogenated Derivatives of N,N-Dimethyl-4-aminoazobenzene at Mercury Electrode

“…The second cathodic peak is most probably due to the catalytic hydrogen wave, as mentioned in the literature. 12,20,21 The first reduction peak of 2′-I-N,N-dimethyl-4-aminoazobenzene was observed at Ep,c = -72 mV in an acidic medium (pH 2.00) and Ep,c = -455 mV in a basic medium (pH 6.83). An anodic peak appears corresponding to the first reduction peak of 2′-halogeno-N,N-dimethyl-4-aminoazobenzene derivatives above a pH value of 4.0.…”

“…This is in complete accordance with the literature. 9,12,[21][22][23] The effect of the concentration is shown in Fig. 4.…”

“…12,20,21 This conclusion is based upon the fact that the peak current decreases and the E1/2 value shifts to a negative potential with increasing pH, while the peak currents become stabilized after a certain pH value, and suppression of the peak after the addition of surface-active compounds, such as TritonX-100. These are the most important features of catalytic hydrogen waves.…”

Polarographic behaviour of 3-(2?-thiazolylazo)-2, 6-diaminopyridine using DC and differential pulse polarography

“…Aromatic azo dyes are a commercially important class of compounds and have been the subject of many polarographic investigations [1][2][3].…”