文献类型：期刊文献

英文题名：Activity Coefficients of CaCl2 in Glycine plus Water and Alanine plus Water Mixtures at 298. 15 K

作者：Zhang Xin-Kuan[1,2];Zhuo Ke-Lei[1];Ma Jing-Jing[1];Liu Hong-Xun[1];Wang Jian-Ji

第一作者：张心宽;Zhang Xin-Kuan

通讯作者：Zhuo, KL[1]

机构：[1]Henan Normal Univ, Sch Chem & Environm Sci, Xinxiang 453007, Peoples R China;[2]Xinxiang Univ, Sch Chem & Chem Engn, Xinxiang 453003, Peoples R China

第一机构：Henan Normal Univ, Sch Chem & Environm Sci, Xinxiang 453007, Peoples R China

通讯机构：[1]corresponding author), Henan Normal Univ, Sch Chem & Environm Sci, Xinxiang 453007, Peoples R China.

年份：2009

卷号：30

期号：9

起止页码：1844-1850

外文期刊名：CHEMICAL JOURNAL OF CHINESE UNIVERSITIES-CHINESE

收录：;WOS:【SCI-EXPANDED(收录号:WOS:000270417800032)】；

语种：英文

外文关键词：Activity coefficient; Gibbs free energy; CaCl2; Glycine; Alanine

摘要：Activity coefficients of CaCl2 in glycine + water and alanine + water mixtures at 298.15 K were determined by cell potential measurements using Ion selective electodes (ISE). The molalities of CaCl2 ranged from 0.01 to 0.20 mol/kg, and those of amino acides ranged from 0.1 to 0.4 mol/kg. The cell potentials were analyzed by the Debye-Huckel extended equation and the Pitzer equation to calculate activity coefficients. The results obtained from the two theoretical models are in good agreement with each other. Standard transfer Gibbs free energy, pair interaction parameters (g(EA)) and salting constants (k(S)) were also evaluated. The results are disscussed in terms of the stereo-chemistry of amino acid molecules and structures and electrostatical interaction models. Activity coefficient of CaCl2 increases with increasing of molalities of amino acids. Standard transfer Gibbs free energy decreases with increasing molalities of amino acids, indicating that the interactions of the amino acides with CaCl2 are thermodynamically attractive in aqueous Solution. Values of g(EA) are negative, indicating that the interactions of these two amino acides with CaCl2 result mainly from the electrostatical attraction.