Abstract: A refined solution theory for solid solubility in upercritical fluid is developed in this paper.For a dilute solution often encountered in heavy solid／fluid binary system,an expression for the chemical potential of solute is obtained by using implifyied OZ equation.The infinitely dilute chemical potential of solute in solution is separated into three parts,the contribution of repulsive force,the contribution of local structure around solute molecule and the long range attraction force in terms of direct correlation function.Concentration effect on the chemical potential of solute is calculated by a modified Wilson model based on Kirkwood-Buffs solution theory.The approach is used to model experimental values for 45 solid／fluid binary systems from literature.The model gives an AAD 11.7％ in contrast with 14.9％ of PR-EOS with vdW-2 mixing rule for all 862 data points and for polar solvent systems the model gives much better results.The partial molar volumes of naphthalene in carbon dioxide predicted by this model are in good agreement with experimetal data．

摘要： 从分子热力学基础出发提出一个适用于固体-超临界流体相平衡的理论模型，溶液中溶质的化学位分解为无限稀溶液化学位及溶质浓度效应两部.无限稀溶液化学位由简化的Oz方程计算，其中包括斥力贡献、局部组成及长程引力项浓度对化学位的贡献由作者根据Kirkwood-Buff溶液理论提出的修正Wilson模型计算．用45个二元系862个数据点对此模型进行检验并和PR方程（vdw-2混合规则）计算结果进行比较，本模型的平均绝对误差为11.7％，而PR方程的结果为14.9％，对极性溶剂体系的计算结果有显著改善.用此模型直接推算的萘-Co_2体系萘的偏摩尔焓和文献数据相吻合