Fe(III)与2,3-二羟基苯磺酸钠配位反应的动力学研究

Kinetic Study on the Coordination of Fe(III) and 2,3-Dihydroxy-benzenesulfonate

[H+]在0.01～0.70mol?L-1范围内,离子强度为1.00mol?L-1,[Fe(III)]>>[配体]、[H+]>>[配体]的条件下,研究了Fe(III)与2,3-二羟基苯磺酸钠(Tiron)的配位反应.发现当[H+]≤3.00×10-2mol?L-1时,[Fe(III)]2对反应速率有明显的贡献.求得了相关反应的动力学参数,从而揭示了FeOH2+和FeOH24+与Tiron配位的解离反应途径及FeOH32+的缔合反应机制,并提出了该配位反应的可能机理.

The kinetics of the coordination of Fe（Ⅲ） and 2,3-dihydroxy-benzenesulfonate （Tiron） has been studied under the condition of ionic strength 1.00 mol·L^-1, [H^＋] from 0.01 to 0.70 mol·L^-1 and [Fe（Ⅲ）]〉〉[Tiron]. The reaction rate investigation showed that if [H^＋] ≤3.00×10^-2 mol·L^-1, [Fe（Ⅲ）]^2 has an unusual contribution to the reaction rate. Kinetic parameters for related reactions have been obtained. For an explanation of each rate constant and kinetic results, a dissociation reaction mechanism of complexation of [Fe（Ⅲ）]^2, Fe2（OH）2^4＋ and Tiron, and an association reaction mechanism of FeOH2^3＋, have been disclosed. A possible mechanism for the coordination reaction has been proposed.