高等学校化学学报

高等学校化学学报 ›› 1990, Vol. 11 ›› Issue (9): 1031.

• 研究简报 • 上一篇    下一篇

乙醇-水混合溶剂中次氮基三乙酸离解平衡的研究

史生华, 李天金, 胡荫华   

  1. 西北大学化学系
  • 收稿日期:1988-11-24 出版日期:1990-09-24 发布日期:1990-09-24
  • 通讯作者: 史生华, 710069

A Study of the Dissociation Equilibria of Nitdiotriacetic Acid in Ethanol-Water Mixtures

Shi Shenghua, Li Tian jin, Hu Yinhua   

  1. Department of Chemistry, Nortluvestern University, Xi'an
  • Received:1988-11-24 Online:1990-09-24 Published:1990-09-24

PDF (PC)

被引次数

5

摘要： 次氮基三乙酸(NTA)在非水或混合溶剂中离解常数的测定尚未见报道,本文用电位法测定了乙醇-水混合溶剂中溶解度较小的NTA的离解常数,用标准盐酸溶液返滴定其钾盐可增加NTA浓度,提高测定准确度。

关键词: 次氮基三乙酸, 离解常数, 乙醇-水混合溶剂

Abstract: The pHpotcntiometric titration was used to determine the dissociation constants of nitrilotri-acetic acid (NTA) in ethanol-water mixtures. The potassium nitrilotriacetate was titrated by a stan-dard solution of hydrochloric acid to increase the accuracy of the determination. In the method it was assumed that n is a mean number of dissociated proton in calculation of the acid dissociation constants. According to the characteristic of NTA, the values of K1 and K2 were obtained by treating the system as the first two-step proton dissociation equilibrium at a low pH, and K3 as the last step at a higher pH. It is found that the values of K1 and K2 decrease with the increase of ethanol content in the solvent, but the value of K3 is just contrary'to this result.

Key words: Nitrilotriacetic acid, Dissociation constant, Ethanol-water solvent

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