物理化学学报 >> 1991, Vol. 7 >> Issue (06): 688-693.doi: 10.3866/PKU.WHXB19910610

研究论文 上一篇    下一篇

邻、间、对位二甲苯在盐的水溶液中的活度系数(II)

谢文蕙; 王豫兴; 姬泓巍   

  1. 北京大学化学系,北京 100871
  • 收稿日期:1990-06-26 修回日期:1991-04-20 发布日期:1991-12-15
  • 通讯作者: 谢文蕙

Activity Coefficients of o-, m-, p- Xylenes in Aqueous Salt Solutions(II)

Xie Wen-Hui; Wang Yu-Xing; Ji Hong-Wei   

  1. Department of Chemistry, Peking University, Beijing 100871
  • Received:1990-06-26 Revised:1991-04-20 Published:1991-12-15
  • Contact: Xie Wen-Hui

摘要: 本文用分光光度法测定了25 ℃下邻、间、对位二甲苯分别在Na_2SO_4、K_2SO_4、(NH_4)_2SO_4、MgSO_4及MgCl_2五种高价盐水溶液中的活度系数f, 所作lgf—c_S(盐浓度)图均呈直线, 并基本通过原点, 符合Setschenow盐效应经验公式。得到的三种二甲苯的盐析次序均为: Na_2SO_4>K_2SO_4>(NH_4)_2SO_4>MgSO_4>MgCl_2。本文还用Debye-MacAulay和Conway-Desnoyers-Smith两种静电理论、Masterton-Lee定标粒子理论、McDevit-Long内压力理论以及改进后的内压力理论(XIPT)对研究体系进行了计算, 结果表明; XIPT计算值比其它理沦计算值更符合实际, 且具有方法简单、适用体系广, 误差小, 盐析常数符号与实际一致等显著优点。

关键词: 盐效应, 盐析, 活度系数, 二甲苯

Abstract: The activity coefficients and sahing-out constants of o-, m-, p-xylenes in six aqueous salt solutions at 25 ℃ are determined by spectrophotometric method. The salts used are Na_2SO_4, K_2SO_4, (NH_4)_2SO_4, MgSO_4 and MgCl_2. The relations logf-c_s are found to he all straight lines through the origin, in agreement with the Setschenow empirical formula. The order of salting-out ability is Na_2SO_4>K_2SO_4>(NH_4)_2SO_4>MgSO_4>MgCl_2
The experimental results of three xylenes are compared respectively with the calculated results of Debye-MacAulay and Conway-Desnoyers-Smith electrostatic theories, Masterton-Lee scaled particle theory and McDevit-Long internal pressure theory and internal pressure theory modified by Xie. The numerical calculation of the modified internal pressure theory agree with experimental data better.

Key words: Salt effect, Salting-out, Activity coefficient, Xylene