甲醇-水、水-丙酸和甲醇-丙酸体系汽液平衡的热力学性质

用新型泵式沸点仪测定了在101.325kPa下甲醇-水、水-丙酸、甲醇-丙酸3个二元系在不同液相组成时的沸点,并用间接法Tpx推算了甲醇-水、水-丙酸、甲醇-丙酸3个二元系的汽相平衡组成y.3个二元体系活度系数的关联分别用W ilson模型、NRTL模型、Margules模型和VanLaar模型进行关联,用最小二乘法求出了它们的液相活度系数模型参数.同时,用这些模型参数来计算它们的汽相组成y.所得的液相活度系数来计算3个二元体系的过量吉布斯自由焓函数GE/RT,并且研究的所有体系之间不存在共沸点.计算的沸点温度与实验的所测得的沸点温度吻合良好,由面积积分法检验这些模型参数计算的3个二元体系相平衡数据得到很好的热力学一致性.

Thermodynamic Properties for Vapor-liquid Equilibrium of Binary System Containing Methanol-Water, Propionic Acid-Water and Methanol-Propionic Acid

Isobaric vapor-liquid equilibrium(VLE) data at 101.325kPa for the three binary systems containing methanol-water,water-propionic acid and methanol-propionic acid are determined by different liquid phase compositions using a novel pump-ebullionmeter.The vapor-phase compositions y are calculated from Tpx by the indirect method.The experimental T-x data are used to estimate Wilson,NRTL,Margules and van Laar model parameters,and these parameters in turn are used to calculate vapor-phase compositions y.The activity coefficients arc correlated are the Wilson,NRTL,Margules and van Laar models through the least square method.The activity coefficients are useful to calculate excess Gibbs function(G~E/RT) for the three binary systems,and all the systems studied here do not exhibit azeotropes.The calculated bubble point temperatures with the model parameters of(activity) coefficients are in good agreement with the experimental data.The thermodynamic consistency of the experimental data for the three binary systems is checked by area test method and is(satisfactory).