物理化学学报 >> 2001, Vol. 17 >> Issue (10): 952-955.doi: 10.3866/PKU.WHXB20011018

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乙醇-水混合溶剂中氨基酸解离热力学性质

王琴萍;吕殿祯;申丽;杨家振   

  1. 辽宁大学化学系,沈阳 110036
  • 收稿日期:2001-04-13 修回日期:2001-06-21 发布日期:2001-10-15
  • 通讯作者: 王琴萍 E-mail:ludianzhen@263.net

Thermodynamic Properties of Dissociation of Amino Acid in Mixed Solvents

Wang Qin-Ping;Lü Dian-Zhen;Shen Li;Yang Jia-Zhen   

  1. Department of Chemistry,Liaoning University,Shenyang 110036
  • Received:2001-04-13 Revised:2001-06-21 Published:2001-10-15
  • Contact: Wang Qin-Ping E-mail:ludianzhen@263.net

摘要: 在乙醇和水混合溶剂中恒定乙醇质量分数x=0.2,应用经典的电动势方法测定无液体接界电池的电动势: Pt,H2(1.013×105 Pa)│HCl(0.01 m),乙醇(x),H2O(1-x)│AgCl-Ag(A) Pt,H2(1.013×105 Pa)│GHCl(m1),G±(m2),乙醇(x),H2O(1-x)│AgClAg(B) 其中GHCl代表甘氨酸的盐酸盐,根据电池(A)和(B)的电动势,用传统的 Debye  Hückel外推方法和该文提出的多项式逼近法,确定了甘氨酸在278.15~318.15 K范围内5个温度下的一级热力学解离常数,两种方法得出的结果在实验误差范围内一致.计算了甘氨酸一级解离过程的其它热力学参数.

关键词: 热力学, 电动势, 解离常数, 甘氨酸

Abstract: The primary thermodynamic dissociation constants of glycine were studied by means of EMF measurements of the cell without liquid junction at different temperatures from 278.15 to 318.15 K in the 0.2 mass fraction of ethanolwater mixed solvent.   The first dissociation constants of glycine were calculated by using the polynomial approach proposed on the basis of Pitzer′s electrolytic solution theory and traditional extrapolation on the basis of extended DebyeHückel equation.The results show that both methods are in agreement with each other.The thermodynamic quantities of the first dissociation process of glycine in the mixed solvent were calculated and the results were discussed.

Key words: Thermodynamic, EMF, Dissociation constant, Glycine