正己烷基亚氨二乙酸与锌(Ⅱ)、镍(Ⅱ)离子络合平衡的研究

来源期刊：中南大学学报(自然科学版)1984年第3期

论文作者：殷群生 张祥麟 陈超球

文章页码：95 - 102

关键词：亚氨二乙酸； 多核络合物； 金属离子浓度； 生成常数； 络合平衡； 配位体； 水混合溶剂； 烷基； 氧己环； 离子强度

摘    要：本文在25±0.1℃,表观离子强度0.1（KNO₃）条件下,用pH电位法测定了正己烷基亚氨二乙酸和Zn²⁺,Ni²⁺在混合溶剂（75％V二氧己环,25%V水）和水溶液中所形成络合物的生成常数;提出了将过量金属离子法与过量配位体法相结合,协同求取络合物生成常数的处理方法。

Abstract: The stability constants of the complexes formed by n-hexyl iminodiacetic acid with Zn （Ⅱ） and Ni （Ⅱ） have been determined pH-potentiometrically at 25 ± 0.1℃ and the apparent ionic strength 0.1 （KNO₃） both in the aqueous solution and in the mixed solvent water-dioxane （75% dioxane by volume）. By applying the method of the excess metal ion, thestability constants K_MA and K_MHA^HA, where M stands for Zn²⁺ or Ni²⁺ and A for C_nH_2n+1N （CH₂COOH）₂, have been evaluated simultaneously. The experimental data were treated with the linear regrossion method and the polynuclear complexes were proved to be absent. The values of stability constant have been refined by successive approximation. The overall stability constant β₂, of the complexes MA₂ has been determi- ned with the method of excess ligand. In the treatment of the experimental data for calculation of β₂, the present authors have derived formulas by combining the excess metal ion method with the excess ligand method. The stabiliy constants evaluated ard tabulated in the following table （25 ± 0.1℃ Apparent ionic strength 0.1 （KNO₃）） catioon logK in aqueous in water dioxane solution （75%dioxane by volume） logK₁ 8.46 11.33 Zn³⁺ logk₂ 6.12 7.93 logk_MHA^HA1.99 3.43 logk₁ 8.97 12.14 Ni_-²⁺ logk₂ 6.71 8.65 logk_MHA^HA1.41 3.05