同位素2011，Vol.24Issue(2)：107-112,6.
离子交换色谱中硼同位素交换反应平衡常数的理论预测
Theoretical Estimation of Equilibrium Constants for Boron Isotopic Exchange Reactions in Ion-exchange Chromatography
摘要
Abstract
The equilibrium constant K for isotopic exchange reactions between boric acid B(OH)3 in the external solution and the main species of B(OH)4- ,B3O3 (OH)52- and B3O3 (OH)4- formed in an ion-exchange resin is one of the fundamental parameters in the study of boron isotopes separation by ion-exchange chromatography. Unfortunately, it is very difficult to determine the K value accurately from experiments. Density function theory(DFT) calculations were used to compute the vibrational frequencies of boron isotopomers of the gas-phase B(OH)3 and B(OH)4- at the B3LYP/6-31G level. The values of reduced partition function ratio(RPFR)of the four boron species, B(OH)3, B(OH)4-, B3O3 (OH)52and B3O3 (OH)4-,were estimated following Urey’s model, using the calculated frequencies obtained from DFT calculation. The equilibrium constant K of isotopic exchange reactions were theoretically obtained as the ratio of the RPFRs of two boron species. The results implied that the isotopic effect between B(OH)3 and B(OH)4- was remarkable with a calculated equilibrium constant K of 1. 025 7 at 25 ℃. However, these K valcues for the reactions between B(OH)3 with other two species, B3O3 (OH)52- and B3()3 (OH)4, were smaller around 1. 017 2 and 1. 008 4, respectively.关键词
离子交换色谱/硼同位素/平衡常数Key words
ion-exchange chromatography/ boron isotopes/ equilibrium constant分类
化学化工引用本文复制引用
王贯春,邹从沛,简敏,李刚,王美玲,刘晓珍,付道贵..离子交换色谱中硼同位素交换反应平衡常数的理论预测[J].同位素,2011,24(2):107-112,6.基金项目
反应堆燃料及材料重点实验室基金(9140C7005010804) （9140C7005010804）
