【作者】 徐丽华；

【导师】 袁亚莉；

【作者基本信息】 南华大学 ， 分析化学， 2010， 硕士

【摘要】 第1章:简单介绍了冠醚化合物的配位特性,其中包括冠醚的良好配位能力、独特的配位选择性及影响冠醚配合物稳定性和选择性的因素(配位体、阴阳离子以及溶剂种类的影响),同时简述了冠醚在金属离子分离方面的应用以及铀(Ⅵ)萃取剂的研究进展。最后对本课题的研究意义和研究内容作了归纳和总结。第2章:以二苯并-18-冠-6作为萃取剂,考察了多种稀释剂、盐析剂及有机介质对二苯并-18-冠-6萃取铀(Ⅵ)的影响,确定了乙酸乙酯为稀释剂,0.1mol/L的KH2PO4为盐析剂、水杨酸为酸性介质的溶剂萃取体系。该萃取体系在选定的条件下,对1×10-4mol/L的铀(Ⅵ)一次萃取率可达82.5%,并计算出了萃取反应的表观平衡常数及热力学函数。第3章:在建立了二苯并-18-冠-6-乙酸乙酯对铀(Ⅵ)萃取体系的基础上,深入探讨该体系在萃取后的有机相中铀(Ⅵ)反萃取方法。比较了多种试剂对有机相中铀(Ⅵ)的反萃率,筛选出了满意的反萃取剂,取得了较好的反萃率。并对反萃取的酸度、浓度、温度等条件进行了讨论。第4章:以水杨酸为介质,二苯并-18-冠-6为萃取剂萃取溶液中的铀(Ⅵ)离子,萃取过程为二苯并-18-冠-6与铀(Ⅵ)离子的配位反应。水相与有相分离后,对有机相进行洗脱、干燥、重结晶,进行元素分析,并用红外、热重等手段进行了表征,推测二苯并-18-冠-6铀(Ⅵ)配合物的可能组成为:｛[UO2 (DB18C6)](NO3)(C7H5O3)｝·2H2O。第5章:钍、铀同属锕系元素,本章根据铀(Ⅵ)、钍(Ⅳ)性质的相似性,用二苯并-18-冠-6作为萃取剂,乙酸乙酯为稀释剂,KH2PO4为盐析剂、水杨酸为酸性介质的萃取体系对溶液中的钍(Ⅳ)进行萃取分离。在选定的实验条件下,应用于模拟样品的测定,对1×10-4mol/L的钍(Ⅳ)离子一次萃取率可达88.5%。并计算出了萃取反应的表观平衡常数及热力学函数。更多还原

【Abstract】 In the first chapter, the coordination characteristics of crown ether was introduced in brief, including good coordination ability, unique coordination selectivity and the factors which may affect the stablity and selectivity of crown ethe(effects of ligands, ions and solvent). The progress about the application of crown ether on separating metal ion was also outlined, the research progress of uranium (Ⅵ) extraction reviewed as well. Furthermore, the significance and contents of this topic were inducted and summarized.In the second chapter , in the condition of DB18C6 as extractant, the impact of a variety of diluents was investigated, such as salting agent and organic medium on the extraction of uranium (Ⅵ). Ethyl acetate as determined agent, 0.1mol /L of KH2PO4 as salting agenthe, salicylic acid medium for solvent extraction system was determined. In the selected conditions of the extraction system, the extraction rate of 1×10-4mol/L of uranium (Ⅵ) was 82.5%, and the apparent extraction equilibrium constant and thermodynamic functions were calculated.In the third chapter, after the extraction of uranium(Ⅵ) in the extraction system of DB18C6 as extractant, acid medium as media , ethyl acetate as diluent, the anti-extraction of the uranium (Ⅵ) from organic phase was investigated. By screening strip feed, the acidity, concentration, temperature, various aspects which affecting strip were discussed, and the optimum strip feed which afforded better stripping rate was obtained.In the forth chapter, th extraction process of using DB18C6-ethyl acetate system for uranium (Ⅵ) in solution was coordination reactionit of DB18C6 and uranium (Ⅵ). After the separation of water phase and oil phase , the oil phase was eluted, dried, recrysted, analyzed by elemental analysis, exosyndromed using infrared spectrum, thermogravimetric Analysis and other methods. Then, the composition of [UO2 (DB18C6)] [NO3] [C7H5O3]｝·2H2O was presumedIn the fifth chapter, there was natural similarity between uranium (Ⅵ) and thorium (Ⅳ) . The extraction system of DB18C6 as extractant, ethyl acetate as diluent, KH2PO4 as salting agent and salicylic acid for the acidic medium was used for extraction of thorium (Ⅳ) in solution. In the selected experimental conditions, the simulation samples was determined with this system, the extraction rate is up to 88.5% in 1×10-4 mol/L thorium (Ⅳ) solution, the apparent equilibrium constant and thermodynamic functionst were also calculated.更多还原