AN ISOTOPIC EXCHANGE STUDY OF THE U(IV)-U(V)-U(VI) EQUILIBRIUM IN AQUEOUS PERCHLORATE SOLUTIONS
AN ISOTOPIC EXCHANGE STUDY OF THE U(IV)-U(V)-U(VI) EQUILIBRIUM IN AQUEOUS PERCHLORATE SOLUTIONS
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高氯酸盐水溶液中U(IV)-U(V)-U(VI)平衡的同位素交换研究
DOI：
10.1021/ja01473a006
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发表时间：
1961
影响因子：
15
通讯作者：
L. Schwartz
中科院分区：
文献类型：
--
作者：
B. Masters;L. Schwartz
在离子强度为2.0的高氯酸盐介质中，用U (IV)-U*(VI)交换测量法研究了U (IV)+ LT (VI) fc> 2U (V)的化学平衡反应。在U （IV）浓度低于0.01 M、温度为25℃及以上的条件下，这条交换路径与竞争性交换反应成功分离。发现平衡反应服从速率定律i？xg=¿[U+ 4][U02++][+]~ 8，速率常数k= 2.13 X 10-7 M1秒。发现活化的热力学量为AH*= 37.5 kcal./mol, AS*= 36 eu，结果与U (IV)-U (V)-U （VI）平衡和U (V)歧化反应的极谱测量结果一致。紫外照射可显著加速U (IV)-U*(VI)的交换速率。
Measurements of U (IV)-U*(VI) exchange have been employed in an investigation of the reaction U (IV)+ LT (VI) fc> 2U (V) under conditions of chemical equilibrium in perchlorate media of ionic strength 2.0. A successful separation of this exchange path from the competitive exchange reaction was found possible at U (IV) concentrations below 0.01 M and tem-peratures of 25 and higher. The equilibrium reaction was found to obey the rate law i? xg=¿[U+ 4][U02++][+]~ 8, with a rate constant of k= 2.13 X 10-7 M1 sec.-1 being observed at 25. Thethermodynamic quantities of activation were found to be AH*= 37.5 kcal./mole and AS*= 36 eu The results are consistent with polarographic measurements of the U (IV)-U (V)-U (VI) equilibrium and of the U (V) disproportionationreaction. The U (IV)-U*(VI) exchange rate was found to be strongly accelerated by ultraviolet irradiation.