Abstract: The study on solubilities of substances in dense gases is one of the most important tasks in supercritical fluid extraction(SFE).On the basis of the association laws and the adsorption theories,this paper puts forward a kind of physicochemical mechanism of SFE.Based on this mechanism an adsorption/association model for calculating solubilities of substances in a supercritical fluid(SCF)has been derived.Some experimental results from the literature were reproduced by means of this model.Very good agreement with these experimental results is found.The physicochemical mechanism reasonably accords with the real process of SFE．

摘要： 根据溶剂化缔合理论及吸附理论，提出了超临界流体萃取的物理化学机理，据此推导出物质在超临界流体中溶解度的吸附／缔合数学模型.并用文献发表的实验数据对模型的适用性进行验算，获得了较满意的结果.说明提出的物理化学机理比较符合真实超临界流体萃取过程.