DTNB电化学行为的探讨

应用电解还原, 紫外和红外光谱及循环伏安等方法, 研究了DTNB在水溶液中和汞电极上的电化学行为。借助于电解还原和ESR技术, 首次检测到在DTNB电解还原中产生的自由基讯号。研究了该自由基的性质和动力学衰变规律。

RESEARCHES ON THE ELECTROCHEMICAL BEHAVIOR OF DTNB

This paper presents an experimental study on the electrochemical behavior of 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB) at hanging mercury drop electrode in aqueous solution. DTNB reduction processes have seen established by means of electrolytic reduction preparation, cyclic voltammetry, UV spectroscopy, IR-spectroscopy and ESR as well as electrochemical methods. It is proved that the disulfide bond (-S-S-) of DTNB is reduced to thiol group at the potential of the reduction wave. It is also confirmed that the nitro group of DTNB is liable to be reduced to amino group during electrochemical reduction. Hence, the final reduction product of DTNB is 5-thio-2-aminobenzoic acid. The carboxyl of DTNB is not likely to be reduced in electrochemical reduction. It has been suggested that DTNB is reduced according to ECE mechanism. The final product of DTNB is oxidizable in reverse cycllic scan. Experimental demonstrations and theoretical analysis of voltammogram giye the following mechanism:...