摘要
The oxidation of Na4Fe(CN)6 complex by S2O8 2- 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-1 HClO4) 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 0.46 V 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.
The oxidation of Na4Fe(CN)6 complex by S2O8 2- 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-1 HClO4) 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 0.46 V 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.
基金
Project supported by the National Natural Science Foundation of China (No. 20171010).
