Abstract: Isobaric vapor-liquid equilibrium (VLE) data at 101.325 kPa for the three binary systems containing dimethyl sulfide-pyridine, dimethyl sulfide-N,N-dimetylacetamide and pyridine-N,N-dimetylacetamide and the ternary system containing dimethyl sulfide-pyridine-N,N-dimetylacetamide were measured by different liquid phase compositions using an ebullionmeter. The activity coefficients were correlated with the Wilson, NRTL, Margules, van Laar and UNIQUAC models. The experimental T-x data are used to these model parameters through the least square method, and these parameters in turn are used to calculate vapor-phase compositions. Moreover, the vapor-phase compositions had been predicted from Tpx according to the function of molar excess Gibbs energy by the indirect method. The activity coefficients are useful to calculate excess Gibbs function for the three binary systems. The VLE data of the ternary system were correlated based on Wilson, NRTL, Margules, van Laar and UNIQUAC model parameters of these binary systems in order to build the thermodynamic model of VLE for the ternary system and obtain the vapor-phase compositions and the calculated bubble points, respectively. The thermodynamic consistency of the experimental VLE data were checked out by means of the Herington test for the binary systems and the McDermott-Ellis test for the ternary system, respectively, and the results showed that VLE data for these systems strictly satisfied thermodynamic consistency.

Key words: dimethyl sulfide, pyridine, N,N-dimethylacetamide, correlation, prediction, vapor-liquid equilibrium

摘要： 在101.325 kPa下用沸点仪测定了二甲基硫醚-吡啶、二甲基硫醚-N,N-二甲基乙酰胺、吡啶-N,N-二甲基乙酰胺3个二元体系以及二甲基硫醚-吡啶-N,N-二甲基乙酰胺三元体系不同液相组成时的汽液平衡数据，3个二元体系活度因子分别用Wilson、NRTL、Margules、van Laar和UNIQUAC模型进行关联，用最小二乘法求出了它们的液相活度因子模型参数，用这些模型参数计算它们的汽相组成。根据过量Gibbs自由能函数，采用间接法由Tpx预测了3个二元系的汽相平衡组成。用所得的液相活度因子计算3个二元体系的过量Gibbs自由能。3个二元体系的Wilson、NRTL、Margules、van Laar和UNIQUAC模型参数分别对所测的三元体系数据进行关联，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和泡点温度。分别由Herington法和McDermott-Ellis法对3个二元体系和三元体系进行热力学一致性检验，结果表明这些相平衡数据满足热力学一致性。

关键词: 二甲基硫醚, 吡啶, N,N-二甲基乙酰胺, 关联, 预测, 汽液平衡