This work is devoted to the study of azeotropes by the method of solvation thermodynamics. In the present work the thermochemistry of alkane solutions in binary mixtures was studied. The infinite dilution solution enthalpies of n -hexane, n -octane, and n -dodecane in binary mixtures were measured at 298.15 K. Alkanes were used as solutes since they are not capable of specific interactions with solvents. It should be noted that the differences in the solution of alkanes in a series of solvents are caused by differences in the interactions between the solvent molecules. Binary mixtures (benzene–cyclohexane) and ( n -hexane–acetone) at different molar ratios, including the compositions corresponding to azeotropes, were used. The composition of both azeotropes obtained by distillation was determined by means of densimetry, and was found to be in good agreement with published data. The compositions of chosen azeotropes insignificantly change with temperature. The excess solution enthalpies of n -alkanes in binary solvents were calculated. It was found that the extremum value of the excess solution enthalpy corresponds to their azeotrope composition.

中文翻译：

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二元混合物中烷烃溶液的热化学：共沸物

这项工作致力于用溶剂化热力学方法研究共沸物。在目前的工作中，研究了二元混合物中烷烃溶液的热化学。正己烷、正辛烷和正十二烷在二元混合物中的无限稀释溶液焓在 298.15 K 下测量。烷烃用作溶质，因为它们不能与溶剂发生特定的相互作用。需要注意的是，烷烃在一系列溶剂中的溶液差异是由溶剂分子间相互作用的差异引起的。使用了不同摩尔比的二元混合物（苯-环己烷）和（正己烷-丙酮），包括对应于共沸物的组成。通过密度测定法测定通过蒸馏获得的两种共沸物的组成，并被发现与公布的数据非常吻合。所选共沸物的组成随温度变化不显着。计算正构烷烃在二元溶剂中的过量溶液焓。发现过量溶液焓的极值对应于它们的共沸物组成。