高等学校化学学报

高等学校化学学报 ›› 1980, Vol. 1 ›› Issue (2): 75.

• 论文 • 上一篇    下一篇

在盐的水溶液中非电解质活度系数的研究(Ⅺ)--正丙酸和正丁酸在苯和盐水溶液间的分配

谢文蕙, 刘文, 刘振义, 马殿坤, 范启家, 黄子卿   

  1. 北京大学物理化学研究所
  • 收稿日期:1980-02-05 出版日期:1980-12-24 发布日期:1980-12-24

STUDIES OF ACTIVITY COEFFICIENTS OF NONELECTROLYTES IN AQUEOUS SALT SOLUTIONS-XI--THE DISTRIBUTION OF n-PROPIONIC ACID AND n-BUTYRIC ACID BETWEEN BENZENE AND AQUEOUS SOLUTIONS OF SALTS WITH SMALL IONS

Xic Wenhui, Liu Wen, Liu Zhenyi, Ma Diankun, Fan Qijia, Huang Ziqing   

  1. Research Laboratory of Physical Chemistry. Beijing University
  • Received:1980-02-05 Online:1980-12-24 Published:1980-12-24

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摘要： 在25℃下分别测定正丙酸和正丁酸在苯相和纯水相中的分配比,以及在苯相和盐水溶液中的分配比,从而求出酸的活度系数。所用的盐有氯化锂、氯化钠、氯化钾、氯化锶、氯化钡、溴化锂、溴化钠、溴化钾等八种。对弱酸算出了未解离部分的活度系数。在所用盐浓度(0-1mol/l)范围内,作lgfu-Cs图,都呈直线。比较直线的斜率,对正丙酸为:SrCl2>BaCl2>LiCl≈NaCl>LiBr≈NaBr>KCl>KBr。对正了酸为:SrCl2>BaCl2>NaCl≈LiC1>NaBr≈KCl≈LiBr>KBr.指出小离子盐对小脂肪酸盐效应主要是静电力作用。

Abstract: The distribution coefficients of n-propionic acid and n-butyric acid have been determined in the benzene phase in equilibrium with the water as well as the aqueous salt solution phases,thus enabling us to get the activity coefficient of each of the acids.The salts used are LiCl,NaCl,KCl,SrCl2,BaCl2,LiBr,NaBr,and KBr.Following the Randall and Failley's treatment of the weak acid,we have calculated the concentrations of its ions and obtained the concentration and finally the activity coefficient of the undissociated part of the acid fuThe salt concentrations Cs used are 0→1 mol e/1.When we plot log fu vs.Csfor the salts,the results obtained are all straight lines.On comparison of the slopes of these lines,the salting-out order is SrCl2> BaCl2>LiCl≈NaCl>LiBr≈NaBr>KCl>KBr for propionic acid,and is SrCl2>BaCl2>NaCl≈LiCl>NaBr≈KCl≈LiBr>KBr for butyric acid.We have calculated the salting-out constants of these acids in the solutions of alkaline and alkaline-earth halides by the formula of (1) Debye-McAulay,(2) McDevit-Long,and (3) Conway-Desnoyes-Smith.With the exception of the lithium salts,they all give the right salting order of the salts,but formula (3) gives the results in better agreement with the experiment than those of (1) and (2).

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