Studies on the mechanism of electroreduction of isonicotinic acid and its carboxylic isomers on mercury cathode

✍ Scribed by Wang Zheng-Hao; Hu Zhi-Bin

• Publisher: Elsevier Science
• Year: 1985
• Tongue: English
• Weight: 764 KB
• Volume: 30
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/0013-4686(85)80127-4

✦ Synopsis

A mercury pool of about 10cmZ was used as a cathode and linear potential sweep were used for voltammetric studies of isonicotinic acid and its carboxylic isomers in aqueous solutions. The authors discovered that at every second scanning in isonicotinic acid solution there began to appear a new wave at a half-wave potential more positive than the original one. These new waves seem to be due to a new intermediate species which is the product of electroreduction of isonicotinicacid. The half-wave potentials of these intermediates bear a linear relationship with pH, slopes of these straight lines being 5540 mV pH_'. These active species decayed according to the second order reaction law and the Zk rate constants have been determined. Also, a coloured substance was observed during the electroreduction of isonicotinic acid. The relationship of the formation of the coloured substance and the simultaneous decay of the active intermediates has been demonstrated. A scheme of the electroreduction is suggested: the first step of the reaction is: