Alkhatib Ismail I I, Vega Lourdes F
Chemical Engineering Department, Khalifa University of Science and Technology, P.O. Box 127788, Abu Dhabi, United Arab Emirates.
J Chem Phys. 2021 Apr 28;154(16):164503. doi: 10.1063/5.0046034.
In this work, polar soft-Statistical Associating Fluid Theory (SAFT) was used in a systematic manner to quantify the influence of polar interactions on the phase equilibria, interfacial, and excess properties of binary mixtures. The theory was first validated with available molecular simulation data and then used to isolate the effect of polar interactions on the thermodynamic behavior of the mixtures by fixing the polar moment of one component while changing the polar moment of the second component from non-polar to either highly dipolar or quadrupolar, examining 15 different binary mixtures. It was determined that the type and magnitude of polar interactions have direct implications on the vapor-liquid equilibria (VLE), resulting in azeotropy for systems of either dipolar or quadrupolar fluids when mixed with non-polar or low polar strength fluids, while increasing the polar strength of one component shifts the VLE to be more ideal. Additionally, excess properties and interfacial properties such as interfacial tension, density profiles, and relative adsorption at the interface were also examined, establishing distinct enrichment in the case of mixtures with highly quadrupolar fluids. Finally, polar soft-SAFT was applied to describe the thermodynamic behavior of binary mixtures of experimental systems exhibiting various intermolecular interactions (non-polar and polar), not only demonstrating high accuracy and robustness through agreement with experimental data but also providing insights into the effect of polarity on the interfacial properties of the studied mixtures. This work proves the value of having an accurate theory for isolating the effect of polarity, especially for the design of ad hoc polar solvents.
在这项工作中，系统地运用了极性软统计缔合流体理论（SAFT）来量化极性相互作用对二元混合物的相平衡、界面性质和过量性质的影响。该理论首先通过现有的分子模拟数据进行验证，然后通过固定一种组分的极矩，同时将第二种组分的极矩从非极性改变为高偶极或四极，研究15种不同的二元混合物，以分离极性相互作用对混合物热力学行为的影响。结果表明，极性相互作用的类型和强度对气液平衡（VLE）有直接影响，当偶极或四极流体与非极性或低极性强度流体混合时会导致共沸现象，而增加一种组分的极性强度会使VLE向更理想的方向移动。此外，还研究了过量性质和界面性质，如界面张力、密度分布和界面处的相对吸附，发现在与高四极流体的混合物中存在明显的富集现象。最后，极性软SAFT被应用于描述表现出各种分子间相互作用（非极性和极性）的实验系统二元混合物的热力学行为，不仅通过与实验数据的一致性证明了其高精度和稳健性，还深入了解了极性对所研究混合物界面性质的影响。这项工作证明了拥有一个准确的理论来分离极性影响的价值，特别是对于特殊极性溶剂的设计。
