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二苯并-18-冠-6-硝基苯,从高浓度的盐酸或氯化物溶液中,能有效地萃取铀(Ⅳ)和铀(Ⅵ)。不同碱金属阳离子对萃取的影响,符合冠醚与阳离子络合作用的顺序:K~+>Na~+>Li~+,少量钾离子的引入能显著提高对铀的萃取效果。通过对有机相中铀性质的研究和固体萃合物的成份分析,指出在被萃取的离子对中铀(Ⅳ)和铀(Ⅵ)是以氯络阴离子[UCl_6]~(2-)、[UO_2Cl_4)~(2-)的形式存在。采用饱和萃取法和等克分子系列法,确定了在盐酸体系中萃合物的组成为:H_2UCl_6·2DBC、H_2UO_2Cl_4·2DBC。当有与冠醚络合作用强的阳离子存在时,萃合物中的氢将被该阳离子所取代。
Dibenzo-18-crown-6-nitrobenzene, uranium (Ⅳ) and uranium (Ⅵ) can be efficiently extracted from high concentration hydrochloric acid or chloride solution. The effect of different alkali metal cations on the extraction is in accordance with the sequence of the complexation between crown ether and cation: K ~ +> Na ~ +> Li ~ +. The introduction of a small amount of potassium ions can significantly improve the extraction effect of uranium. The uranium (Ⅳ) and uranium (Ⅵ) in the extracted ion pairs are characterized by the chloride anions [UCl_6] ~ (2 -), [ UO_2Cl_4) ~ (2-). Saturated extraction and isochromic series were used to determine the composition of the complex in the hydrochloric acid system as follows: H 2UCl 6 · 2DBC and H 2 UO 2 Cl 4 · 2DBC. Hydrogen in the complex will be replaced by the cation when there is a strong cation complexed with the crown ether.