Consideration of mutual orientation structure in equations of state for mixtures

对于化学分离过程来说，从开发到设计再到优化的每一步，混合物的热力学性质都是至关重要的。为此，越来越多地使用状态方程，因为这些方程允许描述和部分预测混合物在大压力和温度范围内的热力学性质。虽然在过去的几十年里，状态方程的发展和应用取得了实质性的进展，但仍然有许多物质和混合物不能用普通的理论来描述。如果研究由极性和非极性物质组成的混合物，情况尤其如此。对于极性物质，特别是混合物中的极性组分，由于它们的电荷分布与排斥力中心有强烈的不对称，处理起来比较复杂。这类成分的一个著名代表是水。这些流体倾向于彼此朝向——它们有优先的朝向分布。这种取向分布可以用本文作者在前期工作中开发的共取向流体静电相互作用泛函方程（COFFEE）来考虑，而一般的状态方程不包括流体结构的这一特征。在这个项目中，该理论将扩展到混合物，其中也考虑了局部浓度不同于感兴趣的混合物的整体浓度。这需要特别注意极性和非极性物质的混合物。这项工作是用状态方程描述复杂水混合物的重要一步。

For chemical separation processes, it is decisive that in each step from development over design to optimization, the thermodynamic properties of mixtures are known well. To this end, there is an increased usage of equations of state, since these allow the description and partially prediction of thermodynamic properties of mixtures in large pressure and temperature ranges. Though there has been substantial progress in the development and application of equations of state during the past decades, there are still many substances and mixtures that cannot be described with common theories. This is especially the case, if mixtures constituting substances with polar character and such with unpolar character are investigated. For the polar substances, especially such components in mixtures are complicated to treat that have a strongly asymmetric charge distribution in relation to the repulsive center. A well-known representative of this class of components is water. Such fluids tend to orient towards each other – they have a preferential orientation distribution. This orientation distribution can be considered using Co-Oriented Fluid Functional Equation for Electrostatic interactions (COFFEE), which was developed in preliminary work of the proposer, while common equations of state do not include this feature of fluid structure. In this project, the theory is to be extended to mixtures, where also the local concentration that differs from the global concentration in mixtures of interest, is considered. This is done with special attention to mixtures of polar and unpolar substances. This work is a substantial step to the description of complex aqueous mixtures with equations of state.