纯物质挥发能力评估的热力学分析

Thermodynamic Analysis of Pure Substances Volatilization

一个大气压下的沸点和特定温度下的饱和蒸气压常用来评估纯物质的挥发能力，但仍缺乏这2个指标为什么能够进行挥发能力评估的热力学分析。以纯液体为对象，依据热力学第二定律，建立热力学模型，对沸点和饱和蒸气压评估纯物质挥发能力的热力学本质进行了分析。同时，对在一个大气压和沸腾温度下的摩尔蒸发焓能否作为纯物质挥发能力的判据进行了热力学分析。分析表明，摩尔蒸发焓可以作为纯物质挥发能力的新评估标准。摩尔蒸发焓越小，则纯物质越容易挥发，反之亦然。

Boiling point under atmospheric pressure and saturated vapor pressure are commonly used to assess the ability of pure substances＇ volatilization. The reason why these two in- dicators can used to evaluate pure substances＇ volatilization is not clear and thermodynamic analy- sis is not completed. In this paper, thermodynamic analysis of pure liquid＇s volatilization was studied, and the thermodynamic model was established according to the second law of thermody- namics. Meanwhile, thermodynamic analysis of whether the molar enthalpy of vaporization at boiling temperature under atmospheric pressure act as a criterion for the volatilization of pure substances was carried out. The results show that the molar enthalpy of vaporization can be used as a new criterion for the volatilization of pure substances. The smaller the molar enthalpy of vaporization, the more easily the pure substances volatilize, and vice versa.