CIESC Journal ›› 2017, Vol. 68 ›› Issue (2): 567-574.DOI: 10.11949/j.issn.0438-1157.20161256

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Force field construction for DMF and vapor-liquid phase equilibrium simulation of acetonitrile-methanol-DMF

ZHANG Qi, CHEN Wenqi, ZENG Aiwu   

  1. State Key Laboratory of Chemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
  • Received:2016-09-08 Revised:2016-10-15 Online:2017-02-05 Published:2017-02-05
  • Supported by:

    supported by the National Key Technology Research and Development Program of the Ministry of Science and Technology of China (2007BAB24B05).

DMF的力场构建及乙腈-甲醇-DMF三元体系的汽液相平衡模拟

张旗, 陈文奇, 曾爱武   

  1. 化学工程联合国家重点实验室, 天津大学化工学院, 天津 300072
  • 通讯作者: 曾爱武
  • 基金资助:

    国家科技支撑计划项目(2007BAB24B05)。

Abstract:

An extensional TraPPE-UA force field for N,N-dimethyl-formamide(DMF) was developed by combination of the quantum chemistry calculation and Gibbs ensemble Monte Carlo simulation, which lays the foundation for the simulation of vapor-liquid phase equilibrium with DMF. First of all, the vapor-liquid phase equilibrium for DMF was calculated in the NVT-Gibbs ensemble by using this new force filed. The results show that the new force field can be used to accurately calculate the saturated liquid densities, vapor pressures, normal boiling point, critical point and heats of vaporization of DMF. Secondly, the vapor-liquid equilibrium for binary mixtures of acetonitrile-methanol, DMF-methanol, DMF-acetonitrile were computed in the NPT-Gibbs ensemble by adopting the TraPPE-UA force field. These simulation results were in good agreement with the experimental data, which validated the reliability of this model. Finally, the vapor-liquid equilibrium data of ternary mixture of acetonitrile-methanol-DMF were predicted in the NPT-Gibbs ensemble, which can provide basic data for design and optimization of the separation process of acetonitrile and methanol.

Key words: N,N-dimethylformamide, Monte Carlo simulation, TraPPE-UA force field, acetonitrile, methanol, vapor-liquid equilibrium, statistical thermodynamics

摘要:

采用量子化学和Gibbs系综Monte Carlo模拟相结合的方法,对TraPPE-UA力场中缺失的N,N-二甲基甲酰胺(DMF)力场参数进行了补充,为含DMF多元体系的汽液相平衡模拟奠定了基础。采用新构建的力场参数,在NVT-Gibbs系综中计算了DMF的汽液相平衡性质,结果表明该力场能准确计算出DMF的饱和液相密度、蒸气压、沸点、临界值和蒸发焓。在NPT-Gibbs系综中,采用TraPPE-UA力场分别计算了乙腈-甲醇、DMF-甲醇、DMF-乙腈二元混合物的汽液相平衡性质,并与实验值进行了比较。模拟结果与实验值较为吻合,验证了力场模型的可靠性。最后在NPT-Gibbs系综中采用TraPPE-UA力场对乙腈-甲醇-DMF三元体系的汽液相平衡数据进行了预测,为设计和优化乙腈和甲醇的萃取分离过程提供了基础数据。

关键词: N,N-二甲基甲酰胺, Monte Carlo模拟, TraPPE-UA力场, 乙腈, 甲醇, 汽液平衡, 统计热力学

CLC Number: