乙醇-乙酸乙酯-二甲基亚砜多元系汽液平衡的热力学性质

Thermodynamic Properties for Vapor-Liquid Equilibrium of Ethanol-Ethyl Acetate-Dimethyl Sulfoxide Multicomponent System

用新型泵式沸点仪测定了101.325 kPa下乙醇-二甲基亚砜、乙酸乙酯-二甲基亚砜2个二元系以及乙醇-乙酸乙酯-二甲基亚砜三元系在不同液相组成时的沸点,并用间接法由Tpx推算了2个二元系的汽相平衡气相组成y。2个二元体系活度系数分别用Wilson、NRTL、Margules和van Laar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,所得的液相活度系数来计算2个二元体系的过量吉布斯自由能函数GE/RT。同时,用这些模型参数来计算它们的汽相组成y,并由2个二元系与1个三元系回归出乙醇-乙酸乙酯二元共沸体系的Wilson模型参数。用3个二元系Wilson模型参数对所测的三元系数据进行关联,建立该系统汽液平衡的热力学模型并计算平衡时的汽相组成y和泡点温度。由面积积分法检验这些模型参数计算的乙醇-二甲基亚砜、乙酸乙酯-二甲基亚砜2个二元系相平衡数据,得到很好的热力学一致性。

Isobaric vapor-liquid equilibrium（VLE） data of different liquid phase compositions at 101.325 kPa for the ternary system containing ethanol-ethyl acetate-dimethyl sulfoxide and the two constituent binary systems containing ethanol-dimethyl sulfoxide,and ethyl acetate-dimethyl sulfoxide were determined using the novel pump-ebullionmeter.The vapor-phase compositions were calculated from Tpx by the indirect method.The experimental T-x data were used to estimate Wilson,NRTL,Margules and van Laar model parameters,and these parameters in turn were used to calculate vapor-phase compositions.The activity coefficients were correlated with the Wilson,nonrandom two-liquid（NRTL）,Margules and van Laar models through the least-squares method.The activity coefficients were useful to calculate excess Gibbs function（GE/RT） for the two binary systems.The optimum Wilson model parameters of the ethanol-ethyl acetate binary system were determined by the linear regression based on the two binary systems and the ternary systems.The VLE data of the ternary system were correlated based on Wilson model parameters of these binary systems to build the thermodynamic model and obtained the vapor-phase compositions and the calculated bubble points.The calculated bubble points with the model parameters of activity coefficients were in good agreement with the experimental data.The thermodynamic consistency of the VLE data for the two binary systems were checked by area test method,and the results were satisfactory.