甲基咪唑类衍生物对镧、锕系元素的萃取研究

发布时间：2018-05-03 04:03

本文选题：甲基咪唑 + 离子液　；参考：《兰州大学》2015年硕士论文

【摘要】：本项研究中,我们发现了一类新型的萃取剂：甲基咪唑(MIM)类衍生物。它们易溶于水相和咪唑基离子液相,并易与软金属配合,可以把镧、锕系元素与钇从水相萃取到离子液相或有机溶剂相。相同实验条件下,我们分别对甲基咪唑类衍生物在离子液与正戊醇稀释剂中萃取镧、锕系元素的情况进行了研究,结果表明在正戊醇中其萃取能力远低于离子液中；我们也研究了NO3-对甲基咪唑类萃取镧、锕系元素的影响,证明NO3-本身参与了萃取反应；此外,我们通过斜率分析研究,证明甲基咪唑在离子液相的萃取过程中与La3+，，Y3+和UO22+等离子形成了1：1的配合物,而与Eu3+,Lu3+和Th4+等形成了1：4的配合物；通过FTIR和ESI-MS等方法对其配合物进行表征,我们得知甲基咪唑类衍生物在离子液中对镧、锕系元素萃取是中性溶剂化机理与阳离子交换机理并存的,而在正戊醇中仅为中性溶剂化机理；我们也开展了竞争性萃取研究,发现甲基咪唑可在镧系元素,碱金属及碱土金属的混合溶液中选择性萃取镧系元素,在镧系元素与铀、钍的混合溶液中选择性萃取钍,表明甲基咪唑对镧系元素和钍有良好的选择性萃取能力；反萃研究中,我们发现甲基咪唑萃取了镧、锕系元素之后可通过较小浓度的硝酸实现反萃；此外,我们对萃取热力学也做了研究,并计算了热力学参数(△H,△S和△G)值,数据表明甲基咪唑萃取镧、锕系元素是一个自发吸热的过程。甲基咪唑作为萃取剂时存在着循环使用性能差和强酸下萃取能力弱等缺点,后续研究中,我们找到了同等萃取机理的2-甲基-2恶唑啉,并将其化学改性而合成了一类固相萃取剂,这类固相萃取剂可有效的改善甲基咪唑类的缺点，在镧、锕系元素的萃取方面有着重要的研究意义。
[Abstract]:In this study, we found a new kind of extractant: methyl imidazolium MIM derivatives. They are easily soluble in aqueous phase and imidazolyl ionic liquid phase, and can be easily combined with soft metal. Lanthanum, actinides and yttrium can be extracted from aqueous phase to ionic liquid phase or organic solvent phase. Under the same experimental conditions, the extraction of lanthanum and actinides in ionic liquid and n-pentanol diluent by methyl imidazole derivatives were studied respectively. The results show that the extraction ability of methyl imidazole derivatives in n-pentanol is much lower than that in ionic liquid. We have also studied the effect of no _ 3- on the extraction of lanthanum and actinides by methyl imidazole, which proves that no _ 3- itself is involved in the extraction reaction; in addition, we have studied it by slope analysis. It was proved that the complexes of methyl imidazole with La3 Y 3 and UO22 plasma were formed at 1:1 while those with Eu3 Lu3 and Th4 formed at 1:4 in the extraction process of ionic liquid phase. The complexes were characterized by FTIR and ESI-MS. We know that the extraction of lanthanum and actinides by methyl imidazole derivatives in ionic solution is a neutral solvation mechanism and a cationic exchange mechanism, but only a neutral solvation mechanism in n-pentanol. We have also carried out competitive extraction studies. It was found that methyl imidazole can selectively extract lanthanide in mixed solution of lanthanide, alkali metal and alkaline earth metal, and thorium in mixed solution of lanthanide, uranium and thorium. The results show that methyl imidazole has good selective extraction ability for lanthanide and thorium. In the back extraction study, we found that lanthanum can be extracted by methyl imidazole, and actinides can be extracted by nitric acid at a lower concentration. We have also studied the extraction thermodynamics and calculated the thermodynamic parameters (H, S and G). The data show that the extraction of lanthanum by methyl imidazole is a spontaneous endothermic process. When methyl imidazole is used as extractant, it has some shortcomings such as poor recycle performance and weak extraction ability under strong acid. In the follow-up study, we found 2-methyl-2 oxazoline with the same extraction mechanism. A kind of solid phase extractant was synthesized by chemical modification. This kind of solid phase extractant can effectively improve the shortcomings of methyl imidazole. It is of great significance in the extraction of lanthanum and actinides.
【学位授予单位】：兰州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O626;TQ028

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