【摘要】 本文介绍五种长碳链的正烷基亚氨二乙酸(Cn H_2n+1 N（CH₂COOH）₂,其中n=6,8,10,12,14)的合成。在25±0.1℃,表观离子强度0.1（KNO₃）的条件下,用pH电位法测定了上述各酸根离子的三级加质子常数。用HClO₁4标定pH计求取了混合溶剂中H⁺的浓度;推导了线性回归法计算K₂H和K₃H的公式。更多还原

【Abstract】 Five n-alkyl iminodiacetic acids CnH_2n+1 N （CH₂COOH）₂, in whichn=6, 8, 10, 12 or 14, were synthesized from chloroacetic acid and thecorresponding amines according to A.Stein′s method. The protonation constants of the five n-alkyl iminodiacetate ions havebeen determined at 25±℃0.1℃ and the apparent ionic strength 0.1 （KNO₃）with the pH-potentiometric method in the mixed solvent water-dioxane（75% dioxane by volume）. The protonation constant of n-hexyl iminodiac-etate ion has also been determined in the aqueous solution at the sametemperature and the same apparent ionic strength with the same method. For these ligands, K₁^H>>K₂^H, but K₂^H and K₃^H differ not much from eachother. Therefore, Bjerrum′s half n （formation function） method was appliedto evaluating the first protonation constants of these ligands while thesecond and third protonaton constants were evaluated with both thelinear regression method and the formulas derived by ourselves. The protonation constants determined are listed in the following table.Protonation constants of n-alkyl iminodiacetates[25±0.1℃, Apparent ionic strength 0.1 （KNO₃）]更多还原