We present new experimental data on the isobaric vapor–liquid equilibria (VLE) of four binary mixtures of water with ethylene glycol, diethylene glycol, triethylene glycol, or tetraethylene glycol, measured at three different system pressures (0.05, 0.07, and 0.1 MPa). Water activity coefficients were estimated from the mixtures boiling temperatures and used to rationalize the effect of the increasing glycols chain length on the molecular interactions with water. The soft statistical associating fluid theory (SAFT) equation of state was used to describe the experimental VLE data of these highly nonideal systems, providing insights into the molecular interactions leading the macroscopic behavior of the mixtures. Glycols and water were both modeled as associating molecules, with models and parameters from previous works, in a transferable manner. Soft-SAFT accurately reproduces the experimental data using one single, state independent, binary interaction parameter to correct the mixtures dispersive energy. It is further shown that the parametrization obtained from the pure glycols can be used to provide accurate predictions of the water activities in aqueous solutions of PEGs of higher molecular weight (600–6000 g/mol) highlighting the soft-SAFT robustness and the soundness of the parametrization used.

中文翻译：

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水和乙二醇等压蒸气-液体平衡的测量和建模

我们提供了水与乙二醇，二甘醇，三甘醇或四甘醇的四种二元混合物的等压汽液平衡（VLE）的新实验数据，在三种不同的系统压力（0.05、0.07和0.1 MPa）下进行了测量。从混合物的沸腾温度估算出水活度系数，并将其用于合理化增加的乙二醇链长对与水的分子相互作用的影响。使用软统计缔合流体理论（SAFT）状态方程来描述这些高度非理想系统的实验VLE数据，从而洞悉导致混合物宏观行为的分子相互作用。乙二醇和水都以可转移的方式建模为关联分子，具有先前工作的模型和参数。Soft-SAFT使用一个单一的，独立于状态的二元相互作用参数准确地再现了实验数据，以校正混合物的分散能。进一步表明，从纯乙二醇中获得的参数化可用于提供对分子量较高（600-6000 g / mol）的PEG水溶液中水活度的准确预测，突出了软SAFT的稳健性和稳固性。使用的参数化。