协同萃取体系的研究——Ⅰ.DMHMP和HEHEHP协同萃取钍的机理
INVESTIGATION OF SYNERGISTIC EXTRACTION Ⅰ. SYNERGISTIC EXTRACTION OF THORIUM BY DMHMP AND HEHEHP
-
摘要: 本文研究了甲基膦酸二(1-甲庚)酯(DMHMP)和2-乙基己基膦酸单(2-乙基己基)酯(HEHEHP)在硝酸介质中对钍的协同萃取。用斜率法测得协萃络合物的组成为Th(NO_3)_2·(HA_2)_2·DMHMP。在20℃时维持离子强度μ=0.5,协萃反应平衡常数logβ_(12)=7.65。并求得了该反应的热力学函数△H,△Z和△S分别为～7.14kcal·mol~(-1)、-10.3kcal·mol~(-1)和10.6cal·mol~(-1)·K~(-1)。依据锥角堆积模型讨论了协萃反应的机理。Abstract: In this paper single and synergistic extraction by di-(1-methyl heptyl) methyl phosphonate(DMHMP)and 2-ethyl hexyl hydrogen 2-ethyl hexyl phos-phonic acid (HEHEHP) for thorium has been investigated respectively. There are three kinds of equilibria in the Th(No3)4-DMHMP-HEHEHP-C8C6 system:The equilibrium constants are determined by the usual slope method and found to be lgβ10=4.47, lgβ20=4.90, lgβ12 = 7.65 (20℃) .By determining the effects of temperature on the distribution ratio, △H , △Z and △S of reaction (2) and (3) are evaluated as follows; △H=-3.34 kcal· mol-1 , △Z=-6.57 kcal·moL-1, △S=-11.0 cal· mol-1·K-1 , for the second reaction. △S=-7.14 kcal ·mol-1 , △Z=-10.3 kcal·mol-1 , △S=-10.6 cal· mol-1·K-1, for the third reaction, In term of cone packing model a possible structure of the synergic extracting complex is proposed.
-
Keywords:
- DMHMP /
- HEHEHP /
- Synergistic extraction /
- Th /
- Equilibrium constants
-
-
[1] 刘本耀等,科技,5,626(1983) 。 [2] 陈洛娜等,核化学与放射化学,6,240(1984) 。 [3] Peppard, D. F. et al., J. Inorg. Nucl. Chem., 24, 979 (1962) . [4] Genov, L. et al., Monotsh. Chem., 100, 594 (1969) . [5] Patil, S. K. et al., J. Radioanal. Chem., 54, 159 (1979) . [6] Patil, S. K. et al., Radiochem. Radioanal. Lett., 44, 239 (1980) . [7] 夏源贤等,核化学与放射化学,7,147(1985) . [8] 钱和生等,核化学与放射化学4,115(1982) . [9] Peppard, D. F. et al., J. Inorg, Nucl. Chem., 7, 231 (1958) . [10] Blake, C. A. et al., PUAE, 28, 289 (1958) . [11] Kennedy, J., AERE C/M-369, Harwell, 1958． [12] Bagnall, K.W. et al., J. Chem. Soc. Dalton. Trans., 1365 (1982) [13] 李醒夫等,堆积饱和原理--锕系元素萃取化学规律研究,放射化学分离学术讨论会论文集,承德,1984年9月.
计量
- 文章访问数: 1753
- HTML全文浏览量: 0
- PDF下载量: 1151
下载:
