混合多元系的间接二次微扰理论及其应用

对于极性混合物体系,本文提出了混合多元系的间接二次微扰理论,通过引入间接微扰参量和对体系的自由能作二次展开,使得具有多层次相互作用的体系的自由能可由相应的硬球混合物体系和相互作用能来计算。由此我们导出了相应的等温汽液平衡计算公式,它不仅能应用于液体混合物体系,而且还能用于含盐体系,因此为含盐体系的汽液平衡计算提供了较为严格的理论基础.通过对平均分布近似引入校正,我们对含LiCl的水—甲醇、水—乙醇体系进行了具体计算,其总压相对偏差分别为5.5％和3.7％,结果令人满意。

THE INDIRECT SECOND ORDER PERTURBATION THEORY AND ITS APPLICATION

In this paper, the indirect second order perturbation theory for multicomponent system of polar mixtures has been presented. By introducing the indirect perturbation parameter and taking twice expansion, the free energy of the system with complicated interactions can be calculated from the relative hard sphere system and interaction potential. From the free energy function derived above, we. can obtain the formula used for the calculation of isothermal Lipuid-Vapor equilibrium,, The treatment and the result obtained appliable not only for liquid-liquid system but also for salted binary mixtures. With the aime of verifying our treatment, we have measured the isothermal Vapor-Liquid equilibrium of LiCl-H_2O-CH_3OH,LiCl-H_2O -C_2H_5OH by the static total pressure method. When compared with experimental value, the result obtained from the present theory is atifactory, the relative percent difference of pressure is 5.5% for Li Cl-H_2O-CH_3OH and 3.69% for LiCl-H_2O-C_2 H_5OH.