化学学报 ›› 1992, Vol. 50 ›› Issue (2): 135-138. 上一篇    下一篇

研究论文

稀土与L-苯丙氨酸配合物的PH电位法及量热滴定法研究

张亚飞;牛春吉;倪嘉缵   

  1. 中国科学院长春应用化学研究所
  • 发布日期:1992-02-15

Study on complexes of rare earth with L-Phenylalanine by potentiometry and Calorimetry

ZHANG YAFEI;NIU CHUNJI;NI JIAZUAN   

  • Published:1992-02-15

本文在25℃和0.15mol.dm^-^3(NaCl)离子强度下, 用pH电位法和量热滴定法测定了十五个稀土元素(Y和除Pm外的镧系元素)与L-苯丙氨酸1:1配合物的稳定常数及热力学函数。L-苯丙氨酸通过-CO^-~2和-NH~2与稀土离子配位, 生成较稳定的1:1配合物。配合物稳定性呈"四分组效应"。配合物稳定性顺序中Y的位置向轻稀土方向移动。体系的熵变是配位反应驱动力。离子的去水化在配位反应中起重要作用。

关键词: 稳定常数, 热力学函数, 稀土金属络合物, 丙氨酸 P, 量热滴定, 配位, 电位法

The stability constants and thermodn. functions for complexes of rare earth with L-phenylalanine were determine by potentiometry and calorimetry at 25?and ionic strength of 0.15 mol/dm3 (NaCl). Stability of the complexes shows the "tetrad effect". The entropy change makes a predominant contribution to the stability of these complexes. The ligand is coordinated to rare earth ions through its-CO2- and -NH2 group, and dehydration of ions plays an important role in coordination reaction.

Key words: STABILITY CONSTANT, THERMODYNAMIC FUNCTION, RARE EARTH METAL COMPLEX, ALANINE P, CALORIMETRIC TITRATION, COORDINATION

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