Separation of the Minor Actinides Americium(III) and Curium(III) by Hydrophobic and Hydrophilic BTPhen ligands: Exploiting Differences in their Rates of Extraction and Effective Separations at Equilibrium
Separation of the Minor Actinides Americium(III) and Curium(III) by Hydrophobic and Hydrophilic BTPhen ligands: Exploiting Differences in their Rates of Extraction and Effective Separations at Equilibrium
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DOI：
10.1080/07366299.2018.1429358
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发表时间：
2018-01-01
影响因子：
2
通讯作者：
Distler, Petr
中科院分区：
文献类型：
--
作者：
Lewis, Frank W.;Harwood, Laurence M.;Distler, Petr
研究了疏水性和亲水性的2，9-双（1，2，4-三嗪-3-基）-1，10-菲咯啉（BTPhen）配体对邻位次锕系元素Am（III）和Cm（III）的络合萃取作用。已经表明，Am（III）在非平衡萃取条件下被疏水CyMe4-BTPhen配体萃取到不同的有机稀释剂中比Cm（III）更快，导致Am对Cm的分离因子（SFAm/Cm）高达7.9。此外，Am（III）相对于Cm（III）的选择性可以通过仔细选择萃取条件（有机稀释剂、接触时间、混合速度、配体浓度）来调节。这种动力学效应归因于较高的假定动力学不稳定性的Am（III）的水络合物对配体取代。还观察到Am（III）/Cm（III）选择性对连接到三嗪环的烷基的结构的依赖性，并且带有直链烷基的BTPhen比CyMe4-BTPhen更不能区分Am（III）和Cm（III）。在平衡萃取条件下，亲水性四磺酸化BTPhen配体络合选择性Am（III）超过Cm（III），并防止Am（III）从硝酸中被疏水性O-供体配体N，N，N，N-四辛基二甘醇酰胺萃取，得到Cm（III）超过Am（III）的分离因子（SFCm/Am）高达4.6。这些结果进一步强调了BTPhen配体用于具有挑战性的化学相似的次要锕系元素Am（III）和Cm（III）的分离的效用。
The complexation and extraction of the adjacent minor actinides Am(III) and Cm(III) by both hydrophobic and hydrophilic pre-organized 2,9-bis(1,2,4-triazin-3-yl)-1,10-phenanthroline (BTPhen) ligands has been studied in detail. It has been shown that Am(III) is extracted more rapidly than Cm(III) by the hydrophobic CyMe4-BTPhen ligand into different organic diluents under nonequilibrium extraction conditions, leading to separation factors for Am over Cm (SFAm/Cm) as high as 7.9. Furthermore, the selectivity for Am(III) over Cm(III) can be tuned through careful choice of the extraction conditions (organic diluent, contact time, mixing speed, ligand concentration). This kinetic effect is attributed to the higher presumed kinetic lability of the Am(III) aqua complex toward ligand substitution. A dependence of the Am(III)/Cm(III) selectivity on the structure of the alkyl groups attached to the triazine rings is also observed, and BTPhens bearing linear alkyl groups are less able to discriminate between Am(III) and Cm(III) than CyMe4-BTPhen. Under equilibrium extraction conditions, hydrophilic tetrasulfonated BTPhen ligands complex selectively Am(III) over Cm(III) and prevent the extraction of Am(III) from nitric acid by the hydrophobic O-donor ligand N,N,N,N-tetraoctyldiglycolamide, giving separation factors for Cm(III) over Am(III) (SFCm/Am) of up to 4.6. These results further underline the utility of the BTPhen ligands for the challenging separation of the chemically similar minor actinides Am(III) and Cm(III).