School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom.
J Phys Chem B. 2010 Mar 25;114(11):3879-86. doi: 10.1021/jp909769c.
Gibbs ensemble Monte Carlo simulations were used to study the vapor-liquid equilibrium of binary mixtures of carbon dioxide + methane and carbon dioxide + difluoromethane. The potential forcefields we employ are all atomistic models, and have not previously been mixed together to study the vapor-liquid equilibrium of the binary mixtures. In addition, we characterize the microscopic structure of these liquid mixtures. In carbon dioxide + methane at 230 K and 56 bar, the microscopic structure of carbon dioxide in the mixture is the same as that in the pure liquid. In carbon dioxide + difluoromethane at 283 K and 56 bar, the presence of carbon dioxide does not noticeably perturb the liquid structure of difluoromethane, but the structure of carbon dioxide is subtly changed, due to a strong interaction between it and difluoromethane. The simulations in the isobaric-isothermal (NPT) ensemble agree well with the experimental data, except at the two extreme regions of the pressure range. The good agreement of most simulated state points with experimental data encourages one to develop more accurate potentials for predicting the thermodynamic properties of these systems as well as other complicated systems, which are less amenable to measurement by experiment.
吉布斯系综蒙特卡罗模拟被用于研究二氧化碳+甲烷和二氧化碳+二氟甲烷二元混合物的汽液平衡。我们使用的势能场都是原子模型，以前没有混合在一起研究二元混合物的汽液平衡。此外，我们还对这些液体混合物的微观结构进行了表征。在 230 K 和 56 巴的二氧化碳+甲烷中，混合物中二氧化碳的微观结构与纯液体中的相同。在 283 K 和 56 巴的二氧化碳+二氟甲烷中，二氧化碳的存在并没有明显干扰二氟甲烷的液体结构，但由于二氧化碳与二氟甲烷之间的强烈相互作用，二氧化碳的结构发生了微妙的变化。等压等温热力学（NPT）系综中的模拟与实验数据吻合良好，除了在压力范围的两个极端区域。大多数模拟状态点与实验数据的良好一致性鼓励人们开发更准确的势来预测这些系统以及其他更难通过实验测量的复杂系统的热力学性质。
