著者

河野 直子 矢野 良子 長島 弘三

出版者

公益社団法人 日本分析化学会

雑誌

分析化学 (ISSN:05251931)

巻号頁・発行日

vol.25, no.9, pp.649-652, 1976

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In order to clarify synergistic effect of organic bases in solvent extraction of rare earth metals, the stability of complexes, HPi<SUP>+</SUP>[M(TTA)<SUB>4</SUB>]<SUP>-</SUP>(HPi<SUP>+</SUP>:&gamma;-picolinium cation, TTA : thenoyltrifluoroacetonate anion, M: Y and La) in basic acetone and in basic dichloromethane was studied by PMR spectroscopy. The La-complex dissociated into a tris-complex in acetone as follows:<BR>HPi<SUP>+</SUP>[M(TTA)<SUB>4</SUB>]<SUP>-</SUP>&rarr;M(TTA)<SUB>3</SUB>+ HTTA+ Pi&hellip;(I)<BR>It was the same reaction that had been proposed by the authors for the Y-complex in acetone. In dichlorometane, both complexes were more stable and the reaction (I) could not be observed. With addition of tributylphosphate (TBP) to acetone solution of the La-complex and to dichloromethane solutions of both complexes, the following reaction, also already proposed for the Y-complex in acetone, occured:<BR>HPi<SUP>+</SUP> [M(TTA)<SUB>4</SUB>]<SUP>-</SUP> <I>n</I>TBP<BR>&rarr;M (TTA)<SUB>3</SUB><I>n</I>TBP+HTTA+Pi&hellip;(II)<BR>Effect of metals or solvents on the equilibrium constant of the reaction (II) could be estimated. The La-complex has a larger constant than the Y-complex, and as for each complex, a larger constant was obtained in acetone than in dichloromethane.