文献类型：期刊文献

中文题名：CaCl_2在甘氨酸+水和丙氨酸+水混合溶剂中的活度系数

英文题名：Activity Coefficients of CaCl_2 in Glycine+Water and Alanine+Water Mixtures at 298.15 K

作者：张心宽[1,2];卓克垒[1];马晶晶[1];刘宏勋[1];王键吉[1]

第一作者：张心宽

机构：[1]河南师范大学化学与环境科学学院;[2]新乡学院化学与化工学院

第一机构：河南师范大学化学与环境科学学院,新乡453007

年份：2009

卷号：30

期号：9

起止页码：1844-1850

中文期刊名：高等学校化学学报

外文期刊名：Chemical Journal of Chinese Universities

收录：CSTPCD;;Scopus;北大核心:【北大核心2008】；CSCD:【CSCD2011_2012】；

基金：国家自然科学基金(批准号:20673033);河南省高等学校创新人才基金(批准号:豫高教[2002]129)资助

语种：中文

中文关键词：活度系数;Gibbs自由能;氯化钙;甘氨酸;丙氨酸

外文关键词：Activity coefficient; Gibbs free energy; CaC12; Glycine; Alanine

摘要：利用离子选择性电极(ISE)测定了298.15K时CaCl2在甘氨酸+水和丙氨酸+水混合溶剂中的活度系数.CaCl2的质量摩尔浓度变化范围为0.01～0.20mol/kg,氨基酸的质量摩尔浓度变化范围为0.10～0.40mol/kg.用Debye-Hckel扩展方程和Pitzer方程进行理论计算得到的活度系数基本一致.依据McMillan-Mayer理论,计算了CaCl2从纯水到氨基酸水溶液的标准转移Gibbs自由能,利用最小二乘法拟合求得了对相互作用参数(gEA)和盐效应常数(ks).讨论了这两种氨基酸的加入对CaCl2的活度系数、热力学稳定性及盐效应常数的影响.
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-Htickel 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 （gEA） and salting constants （ks ） 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 aeides with CaCl2 are thermodynamically attractive in aqueous solution. Values of gEA are negative, indicating that the interactions of these two amino acides with CaCl2 result mainly from the electrostatical attraction.