定标粒子理论预测乙醇－水体系汽液平衡盐效应

Prediction of Salt Effect on Vapor-Liquid Equilibrium in Ethanol-Water System by Scaled Particle Theory

测定了７０℃下３个１－１型电解质（ＮａＣｌ、ＮａＢｒ、ＫＣｌ）在各种不同浓度的乙醇－水体系中的汽液平衡盐效应参数，并给出用定标粒子理论计算盐效应参数的方法。硬球作用项采用Ｍａｓｔｅｒｔｏｎ－Ｌｅｅ方程，软球作用项采用胡英的径向分布函数。分子间力在Ｌｅｎｎａｒｄ－Ｊｏｎｅｓ位能函数基础上计入偶极－偶极、偶极－诱导偶极、电荷－偶极、电荷－诱导偶极的贡献，其中离子－分子间的静电作用项仅限于规则排列的第一配位圈之内。将混合溶剂的局部介电常数视为液相浓度的函数，函数关系由实验拟合。在乙醇浓度变化的很大范围内，３个体系的预测与实验结果基本相符。

The salt effect parameters(from Furter's equation)of three electrolytes (NaCl ,NaBr, KCl) for various ethanol-water mixtures were determined by vapor-liquid equilibriumexperiments.A calculation method of this parameter(K)by the scaled particle theory wassuggested.The term of hard sphere interactions was calculated by using Masterton-Lee's equation.and that of soft sphere interactions was treated by using Y.Hu's radial distributionfunction method, i.e.taking the first coordination shell as in order,and out of the shell asrandom mixing.The interactions between the charge of ions and dipole or induced dipole ofthe central molecule were considered effectively within the limits of the first coordinationshell,and the ions out of the shell were regarded as L-J molecules. In this paper a correlation equation for the located dielectrical constant and liquid concentration was proposed andthe predicted results of the salt effect parameters were in agreement with the experiments bythis equation.