Outcalt Stephanie L, Laesecke Arno
, Material Measurement Laboratory, Applied Chemicals and Materials Division, 325 Broadway.
J Mol Liq. 2019 Dec;279. doi: 10.1016/j.molliq.2018.12.123.
Compressed-liquid densities of the binary system dimethyl carbonate + heptane have been measured with a vibrating-tube densimeter over the temperature and pressure ranges of 270 K to 470 K, and 1 MPa to 50 MPa at three compositions of the mixture. The measurements are part of an effort to better understand the molecular interactions of polar/non-polar mixtures. These types of mixtures often exhibit very non-ideal behavior. By measuring the mixture at three compositions and over a large range of temperature and pressure, the non-ideality can be assessed. There are no high-pressure liquid density data for this binary system in the literature, thus data reported here could only be compared to literature data at atmospheric pressure to establish their quality. The majority of literature data agree well with the presented results which have a maximum expanded uncertainty of 1.63 kg·m (for the composition with the greatest mole fraction of dimethyl carbonate). The non-ideality for the mixture, in the temperature, pressure and composition range of this study was found to be minimal. This is rationalized by considering the molecular sizes, shapes, and charge distributions of the pure components and the attractive parts of their intermolecular force fields as they are reflected in the temperature ranges of their vapor pressure curves.
使用振动管密度计，在270 K至470 K的温度范围以及1 MPa至50 MPa的压力范围内，对碳酸二甲酯 + 庚烷二元体系的压缩液体密度进行了测量，测量时混合物有三种组成。这些测量是为了更好地理解极性/非极性混合物分子间相互作用所做努力的一部分。这类混合物通常表现出非常不理想的行为。通过在三种组成以及大范围的温度和压力下测量混合物，可以评估其非理想性。文献中没有该二元体系的高压液体密度数据，因此这里报告的数据只能与大气压下的文献数据进行比较以确定其质量。大多数文献数据与给出的结果吻合良好，给出结果的最大扩展不确定度为1.63 kg·m（对于碳酸二甲酯摩尔分数最大的组成）。在本研究的温度、压力和组成范围内，发现该混合物的非理想性最小。通过考虑纯组分的分子大小、形状和电荷分布以及它们分子间力场的吸引部分（这在它们蒸气压曲线的温度范围内有所体现），可以对此做出合理解释。
