协同萃取规律的研究 Ⅷ.AAB类三元体系(TTA+PMBP+TOPO)协萃硝酸铀酰研究
INVESTIGATION OF THE REGULARITY OF SYNERGISTIC EXTRACTION Ⅶ.SYNERGISTIC EXTRACTION OF URANYL NITRATE BY THE TERNARY SYSTEM OF AAB SPECIES COMPOSED OF TTA-PMBP-TOPO
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摘要: 本文研究铀(Ⅵ)的三元协萃规律。AAB类是在研究了ABC类(PMBP+TBP+(C_6H_5)_4AsCl)、(TTA+DBSO+(C_6H_5)_4AsCl),ABB类(PMBP+TBP+DPSO)、(HTTA+TBP+DPSO)分别从硫氰酸和硝酸底液萃取U(Ⅵ)基础上,新找到的三元协萃体系。本文报道α-噻吩甲酰三氟丙酮(TTA)与1-苯基3-甲基4-苯甲酰基吡唑啉酮-5(PMBP)、三辛基氧化膦(TOPO)的氯仿溶液,萃取硝酸铀酰的协萃效应。用斜率法确定了二元及三元协萃络合物的组成UO_2(TTA)_2·TOPO、UO_2(PMBP)_2·TOPO、UO_2(TTA)(PMBP)·TOPO,分别求得其协萃反应平衡常数的平均值为1gβA_1B=3.85(TTA+TOPO);1gβA_2B=5.29(PMBP+TOPO);1gβA_1A_2B=4.87(TTA+PMBP+TOPO)。并用锥角模型计算了配位体的立体角系数和,确定了协萃络合物的空间堆积程度。Abstract: The synergistic extraction of uranyl nitrate with binary system of thenoyltrifluoroacetone (TTA) and 1-phenyl-3-methyl-4-benzoyl-pyrazolone (PMBP) with trioctyl phosphine oxide (TOPO) and ternary system of TTA-PMBP-TOPO in chloroform solution are studied.The binary synergistic equilibrium constants are determined to be lgβA1B=3.85(TTA+TOPO system) and lgβA1B=5.29(PMBP + TOPO system) respectively.The purpose of this study is to investigate the ternary synergistic extracting mechanism of AAB species. It is found that synergic effect occured during the extraction of uranyl nitrate with the chloroform solution of TTA+PMBP + TOPO. The formation of a ternary extracted complex UO2(TTA)(PMBP)TOPO is confirmed by the usual slope method. According to the solid angle sum rule, the ternary synergic complex UO2(TTA)(PMBP)TOPO is predicted to be stable. A method proposed by Wang Wenqing3 is used for the calculation of the ternary synergistic equilibrium constant which is evaluated to be lgβA1A2B=4.87.
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