Department of Chemistry, University of Pecs, Ifjusag utja 6., H-7624 Pecs, Hungary.
J Phys Chem A. 2010 May 13;114(18):5752-8. doi: 10.1021/jp101458e.
The thiosulfate-iodate reaction has been studied spectrophotometrically in slightly acidic medium at 25.0 +/- 0.1 degrees C in acetate/acetic acid buffer by monitoring the absorbance at 468 nm at the isosbestic point of iodine-triiodide ion system. The formation of iodine after the Landolt time follows a rather complex kinetic behavior depending on the pH and on the concentration of the reactants as well. It is shown that the key intermediate of the reaction is I(2)O(2), its equilibrium formation from the well-known Dushman reaction along with their further reactions followed by subsequent reactions of HOI, HIO(2), S(2)O(3)OH(-), and S(2)O(3)I(-) adequately accounts for all the experimentally measured characteristics of the kinetic curves. A 19-step kinetic model is proposed and discussed with 13 fitted and 7 fixed parameters in detail.
硫代硫酸盐-碘酸盐反应在 25.0 ± 0.1°C 的醋酸/乙酸缓冲介质中进行了分光光度研究，在碘三碘离子体系的等色点处监测 468nm 处的吸光度。在兰多尔特时间之后形成的碘遵循相当复杂的动力学行为，这取决于 pH 值和反应物的浓度。结果表明，反应的关键中间体是 I(2)O(2)，其从众所周知的 Dushman 反应中平衡形成，以及它们的进一步反应，随后是 HOI、HIO(2)、S(2)O(3)OH(-)和 S(2)O(3)I(-)的后续反应，充分说明了动力学曲线的所有实验测量特性。提出并讨论了一个 19 步的动力学模型，其中包括 13 个拟合参数和 7 个固定参数。
