【摘要】 用停止-流动分光光度法研究了Eu²⁺与二甲酚橙（XO）间快速电子转移反应的动力学规律。求得了速控步骤的动力学参数。如反应级数（n=2）、几个不同温度下的速率常数(k_278K=5.7×10⁸L·mol^-·s^-1,k_s38K=1.01×10⁹L·mol^-1·s^-1)、活化能(E=7.6×10³J·mol^-1),以及指前因子(A=1.5×10¹⁰L·mol^-1·s^-1),并判断出其为溶液中扩散控制型反应。根据实验现象与测试结果,提出了Eu²⁺与XO的反应分别在Eu²⁺相对过量和在XO过量时的反应机理,并判断了各反应步骤速率常数之间的相对关系。更多还原

【Abstract】 The kinetics and mechanism of the reaction between Eu²⁺ and Xylenol orange（XO） in aqueous solution has been studied by means of stop-flow spectrophotometricmethod. The kinetic parameters of the rate-controlling step, i,e, reaction order （n=2）, rate constant at various temperatures (k_278K=5. 7×10⁸L·mol^-1·s^-1,k_338K=1. 01×10⁹L·mol^-1·s^-1…), activation energy (E=7. 6×10³J·mol^-1) and preexponentialfactor (A=1. 5×10¹⁰L·mol^-1·s^-1) have been determined. It has been established thatthe electron transfer reaction between Eu²⁺ and XO is a diffusion controlled reaction. The possible mechanisms of the reaction between Eu²⁺ and XO both in the pre-sence of excess XO and Eu²⁺ also have been suggested. The relation between the rateconstants of each step were estimated.更多还原