文献类型：期刊文献

英文题名：Activity coefficients of CaCl2 in (serine or proline + water) mixtures at T = 298.15 K

作者：Ma, Jingjing[1]; Zhang, Xinkuan[1,2]; Zhuo, Kelei[1]; Liu, Hongxun[1]; Wang, Jianji[1]

第一作者：Ma, Jingjing

通讯作者：Zhuo, K.

机构：[1] School of Chemistry and Environmental Science, Henan Normal University, Xinxiang, Henan 453007, China; [2] School of Chemistry and Chemical Engineering, Xinxiang University, Xinxiang, Henan 453003, China

第一机构：School of Chemistry and Environmental Science, Henan Normal University, Xinxiang, Henan 453007, China

年份：2010

卷号：42

期号：5

起止页码：689-694

外文期刊名：Journal of Chemical Thermodynamics

收录：EI(收录号：20100912743635);Scopus(收录号：2-s2.0-77549087085)

基金：Financial supports from the Innovation Foundation of Colleges and Universities of Henan Province and the National Natural Science Foundation of China (No. 20673033 ) are gratefully acknowledged.

语种：英文

外文关键词：Activity coefficients - Amino acids - Free energy - Gibbs free energy - Ion selective electrodes

摘要：Activity coefficients for the (CaCl2 + amino acid + water) system were determined at a temperature of 298.15 K using ion-selective electrodes. The range of molalities of CaCl2 is (0.01 to 0.20) mol · kg-1, and that of amino acids is (0.10 to 0.40) mol · kg-1. The activity coefficients obtained from the Debye-Hückel extended equation and the Pitzer equation are in good agreement with each other. Results show that the interactions between CaCl2 and amino acid are controlled mainly by the electrostatic interactions (attraction). Gibbs free energy interaction parameters (gEA) and salting constants (kS) are positive, indicating that these amino acids are salted out by CaCl2. These results are discussed based on group additivity model. ? 2010.