恒电位库仑法研究硫在有机溶剂中的还原过程

实验证明,第1步还原E_(1/2)=-0.96V(文中所有的电位均相对于Ag参比电极);第2步E_(1/2)=-1.56V。该体系的特征是伴随的均相反应具有较低的速率常数,在一般的循环伏安法扫描时间内很难觉察到均相反应的进行。若采取时间窗较长的实验方法,将有利于观察伴随均相反应的动力学效应。恒电位库仑法时间域约为100～

Researches on Reduction of Sulfur in Organic Medium by Controlled Potential Coulometry

The controlled "potential coulometry is suitable for examining the effects of slower reactions coupled to the electron transfer process such as in sulfur-DMSOsystem, since the time window of this method is longer. The theorietical treatment for the first step of sulfur reduction was completed, while the working curve of T_1/2 -lgr that allowst he determination of apparent rate constant for reaction S₈^2-= S₆^2-+ (1/4)S₈ with a value of k=6×10^-3s^-1 was given. In the second step of sulfur reduction, the electrolysis curve with almost a horizontal at begining and a wave shape at some later were found. The experimental phenomena were explained on the base of results obtained previously.