硫在疏质子介质中电化学还原机理的研究 II: 第二步氧化还原过程的研究

用电化学方法研究了硫在DMSO溶剂中的第二步氧化还原过程. 该过程在扫速大于200mV/s时表现为简单的电子转移过程; 扫速小于200mV/s时转化为ECE机理. 发现了S8^4^-, S3^2^-, S4^2^-的氧化峰, 峰电位分别为 -1.50, -0.96, -0.60(相对于银参比电极), 对S8^2^-/S8^4^-电对测定了标准电极电位和标准速率常数, 分别是-1.547±0.002V(相对于银参比电极)和3.3×10^-^3cm/s.

Studies on electroreduction mechanism of sulfur in aprotic medium II: Researches of the second redox step

The mechanism of the 2nd step of electroredn. of S in DMSO was studied by electrochem. methods. The reduction process appears as a simple electron transfer reaction when the scan rate is >200 mV/s and becomes complicated by coupled homogeneous reactions (ECE mechanism) when the scan rate is <200 mV/s. Sep. anodic peaks for S84-, S32- and S42- were discovered at potentials of -1.50, -0.96 and -0.60V, resp. (vs. a Ag ref. electrode). The formal standard potential and standard rate constant for the S82-/S84- couple were calculated to be -1.547 ?0.002V vs. a Ag. ref. electrode and 3.3 ?10-3 cm/s, resp.