Kinetic Studies on the Reaction of Sodium Hexacyanoferrate(Ⅱ) Complex with Peroxydisulfate Anion

• 来源期刊: 中国化学（英文版）
• 年，卷（期）: 2004,（8）
• 页码范围: 841-844
• 页数: 4页
• 语种: 英文

摘要

The oxidation of Na4Fe(CN)6 complex by S2O82- anion was found to follow an outer-sphere electron transfer mechanism. We firstly carried out the reaction at pH= 1. The specific rate constants of the reaction, kox, are (8.1 ±0.07)×10-2 and (4.3±0.1)×10-2 mol-1·L·s-1 at μ=1.0 mol·L-1 NaClO4, T=298 K for pH=1 (0.1 mol· L-1HC1O4) and 8, respectively. The activation parameters, obtained by measuring the rate constants of oxidation 283-303 K, were △H≠=(69.0±5.6) kJ·mol-1, △S≠=(-0.34±0.041)× 102 J·mol-1·K-1 at pH=1 and △H≠=(41.3 ±5.5) kJ·mol-1, △S≠=(- 1.27±0.33)× 102 J·mol-1·K-1 at pH=8, respectively. The cyclic voltammetry of Fe(CN)36-/4- shows that the oxidation is a one-electron reversible redox process with E1/2 values of 0.55 and 0.46V vs. Normal hydrogen electrode at μ= 1.0 mol·L- 1 LiClO4, for pH= 1 and pH= 8 (Tris), respectively. The kinetic results were discussed on the basis of Marcus theory.