高等学校化学学报

高等学校化学学报 ›› 1993, Vol. 14 ›› Issue (10): 1405.

• 研究论文 • 上一篇    下一篇

二价金属离子萃取速率常数与软硬酸碱规则

孙思修1, 高自立1, 沈静兰1, 杨天林2   

  1. 1. 山东大学化学系, 济南 250100;
    2. 宁夏大学化学系
  • 收稿日期:1992-10-06 修回日期:1993-03-05 出版日期:1993-10-24 发布日期:1993-10-24
  • 通讯作者: 孙思修, 男, 48岁, 副教授.
  • 作者简介:孙思修, 男, 48岁, 副教授.
  • 基金资助:

    国家自然科学基金

The Correlation Between the Extraction Rate Constants of Divalent Metal Ions by HEHEHP and the HSAB Rule

SUN Si-Xiu1, GAO Zi-Li1, SHEN Jing-Lan1, YANG Tian-Lin2   

  1. 1. Chem.Dept., Shandong Univ., Jinan, 250100;
    2. Chem.Dept., Ningxia Univ., Yinchuan
  • Received:1992-10-06 Revised:1993-03-05 Online:1993-10-24 Published:1993-10-24

PDF (PC)

被引次数

4

摘要： 用上升液滴法测定了2-乙基己基膦酸单(2-乙基己基)酯-正辛烷从硝酸介质中萃取镁、钙、锌、镍、铜和铅等二价金属离子的正向初始速率,建立了速率方程,计算出正向萃取反应的速率常数、活化能及活化熵,首次将软硬酸碱规则与金属溶剂萃取速率常数关联.结果表明,在萃取机理相同时,萃取速率常数的大小与金属离子的软硬酸碱标度一致,即萃取过程中,作为酸的被萃取金属离子,其硬度越大,萃取速率常数亦越大,萃取反应的活化能越小.

关键词: 2-乙基己基膦酸单(2-乙基己基)酯, 萃取动力学, 软硬酸规则, 二价金属

Abstract: The kinetics and mechanism of extraction of Mg(Ⅱ), Ca(Ⅱ), Zn(Ⅱ), Ni(Ⅱ), Cu (Ⅱ) and Pb(Ⅱ) from nitrate medium with 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (HEHEHP) in octane by means of the single drop method were studied at 298 K.The reaction rate constants (kf), the activation energies (Ea) and the activation entropies (ΔS≠) were calculated.The experimental results indicate that the extraction process may be controlled by the following interfacial reactions: M2+ +HA(i)=MA(i)+H+(fast)MA(i)+ 2H2A2(O)=MA2 · 2HA(O)+HA(i)+H+(slow) and their kf and Ea vary regularly with the change of hardness of Lewis acid.

Key words: 2-Ethylhexyl phosphonic acid mono-2-ethylhexyl ester, Extraction kinetics, Rule of hard and soft acids and bases(HSAB), Divalent metal ions

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