Mixtures of alkanes and ethanol are important in many areas, for example, as fuel blends. This paper describes new experimental data obtained for the liquid-liquid equilibrium phase behavior of normal alkanes (n-alkanes; CnH2n+2; 9 ≤ n ≤ 24) with ethanol. The results were obtained by applying the cloud point method in a temperature range of T = 230-423 K at ambient pressure. All systems are partially miscible with an upper critical solution point. The two phase regions of the phase diagrams show no indication of any obvious optical irregularities, like birefringence, coloring, formation of schlieren, or remarkable turbidity, except critical opalescence. With increasing length of the molecular chain of the n-alkanes, the (liquid-liquid) critical point is shifted to higher temperatures and higher ethanol content. The data are analyzed numerically implying Ising criticality. The nonsymmetric shape of the phase body is considered in different approaches for describing the diameter by presuming (a) the validity of the rectilinear diameter rule, (b) a nonlinear diameter predicted in the theory of complete scaling, and (c) combining both concepts. The numerical analysis yields the critical temperature, the critical composition, the width, and the diameter of the phase diagrams. The results are compared with literature data sets from similar mixtures; these data are also evaluated in terms of the models applied here. Phase diagrams of 13 different sets of mixtures are measured and analyzed to extract general aspects of the behavior of the normal alkane-ethanol mixtures. A simple Flory-Huggins-like approach allows a semiquantitative description of the experimental results of the critical temperatures. Therefore, it confirms the picture of molecular ordering within the solutions.

中文翻译：

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回顾正构烷烃和乙醇的液相行为。

烷烃和乙醇的混合物在许多领域都很重要，例如，作为燃料混合物。本文介绍了有关正构烷烃（正构烷烃； CnH2n + 2； 9≤n≤24）与乙醇的液-液平衡相行为的新实验数据。通过在环境压力下在T = 230-423 K的温度范围内应用浊点法获得结果。所有系统都可以在较高的临界解决方案点上部分混溶。相图的两个相区域没有显示任何明显的光学不规则性，例如双折射，着色，石纹石的形成或明显的浊度，但临界乳光除外。随着正构烷烃分子链长度的增加，（液-液）临界点转移到更高的温度和更高的乙醇含量。对数据进行数值分析以暗示Ising临界度。通过假定（a）直线直径规则的有效性，（b）在完全缩放理论中预测的非线性直径，以及（c）结合这两个概念，在描述直径的不同方法中考虑了相体的非对称形状。数值分析得出相图的临界温度，临界成分，宽度和直径。将结果与相似混合物的文献数据集进行比较；这些数据也将根据此处应用的模型进行评估。测量并分析了13种不同混合物的相图，以提取常规烷烃-乙醇混合物行为的一般方面。一种简单的类似于Flory-Huggins的方法可以对临界温度的实验结果进行半定量描述。因此，它确定了溶液中分子有序的情况。