Novel Mechanisms of Synergism and Coextraction caused by Metal Chelates as Complex Ligand

1. 2-噻吩甲酰三氟丙酮（HTTA）对镧系元素（Ln），尤其是La^<3+>的萃取，沿着对Al^<3+>、Sc^<3+>和Fe^<3+>等易被萃取到有机相中的金属离子的萃取，即发现了共萃取。通过平衡和红外光谱研究，发现共萃取是由于Ln（tta）_3与M（tta）_3在有机相中形成1：1的加合物或双核配合物。在乙酰丙酮（HATOH）体系中。Cu^<2+>和Zr^<4+>对Ln的共萃取也是由于双核配合物的形成。2. Co（Ta）_3和CO（Ta）_3的加入对HTTA萃取碱土金属（AE）如Sr^<2+>和Ba^<2+>有协同增强作用。这种协同作用归因于AR（tta）_2与Co形成双核配合物。当Al^<3+>或Fe^<3+>以M8 TTA）_3的形式被萃取到有机相中时，HTTA对Sr^<2+>的萃取作用增强。3.研究了4-异丙基托泊酚酮（Hipt）对稀土金属（III）（RE）的共萃取。Co（ipt）_3是HTTA萃取稀土的有效配体，但不影响萃取效果。另一方面，当Sc^&lt;3 +&gt;、Y^&lt;3+&gt;和Lu^&lt;3 +&gt;的萃取量为3 × 10^ M时，LA^&lt;3+&gt;的萃取量（分配比）分别增加了60、80和200倍<-5>。由于已知稀土二聚体在Hipt体系中被萃取，本研究中发现的共萃取可以归因于稀土异双核配合物的形成。

1.Extraction of lanthanide(III) (Ln), especially La^<3+>, with 2-thenoyltrifluoroacetone (Htta) was remarkably enhanced along with the extraction of metal ions such as Al^<3+>, Sc^<3+>, and Fe^<3+> which are readily extracted to the organic phase; that is the coextraction was found out. From the equilibrium and IR studies, the coextraction was found to be ascribed to the formation of a 1:1 adduct or binuclear complex of Ln(tta)_3 with M(tta)_3 in the organic phase. In the acetylacetone (Hacae) system. Cu^<2+> and Zr^<4+> caused the coextraction of Ln, which was also due to the formation of binuclear complexes.2.Synergistic enhancement of the extraction of alkaline earth metals(II) (AE) such as Sr^<2+> and Ba^<2+> with Htta was found by the addition of Co(acae)_3 and CO(tta)_3. The synergism was ascribed to the formation of a binuclear complex of AR(tta)_2 with the Co chelates. Furthermore, the extraction of Sr^<2+> with Htta was enhanced when Al^<3+> or Fe^<3+> was extracted into the organic phase as M8TTA)_3. This phenomenon is the coextraction of AE along with the extraction of AL^<3+> or Fe^<3+>.3.The coextraction of rare earth metals(III) (RE) with 4-isopropyltropolone (Hipt) has been studied. The extraction of RE was not affected by the addition of Co(ipt)_3 although it acted as an effective complex ligand in the extraction of RE with Htta. On the other hand the extraction (distribution ratio) of LA^<3+> was increased by a factor of 60,80, and 200 with the extraction of 3x 10^<-5> M Sc^<3+>, Y^<3+>, and Lu^<3+>, respectively. Since the RE-dimers are known the be extracted in the Hipt system, the coextraction found in this study can be ascribed to the formation of hetero-binuclear complexes of RE.