Polarography of 7-nitro-8-hydroxyquinoline-5-sulphonic acid

The–NO2 group reduction in 4-nitrophthalic acid (NPA) at dropping mercury electrode over a wide range of PH, is irreversible and diffusion controlled. Ill defined waves preceded the —NO2 group wave, were observed between PH 7 and 12 whereas at PH 5.0, a rounded maximum appears. The a. c. reduction of NPA at PH 12.0, provides two peaks, first peak corresponds to d. c. pre-step, is essentially due to adsorption phenomena whereas other peak is the reduction wave. Using McBain Down cell and King-cathcart equation the diffusion coefficient of NPA is 0.713×10-3 cm2sec-1. Six electrons are being involved in nitro group reduction and mechanism of the reduction was suggested. The kinetic parameters in absence and presence of ionic and non-ionic surfactants were determined. The reduction process becomes more and more irreversible as surface activity of organic compounds increases. Ionic surfactants are effective in increasing the value of —log K° than the non-ionic surfactants. The value of ana decreases regularly by the presence of compounds having regular increase of surface activity.

N. Kishore

Papers

Polarography of 5-nitro-ace-naphthene