This study presents the influence of molecular interaction and molecular ordering on the physicochemical properties and the excess values of the binary mixtures containing several alkanediols and a symmetric cyclic ketone (cyclopentanone) at 298.15 K and 101.3 kPa. Thus, experimental values of the permittivity, density, and refractive index were determined for the alkanediol–cyclopentanone systems over the entire range of mole fraction. A series of straight-chain primary alkanediols, each having two primary hydroxyl groups, were 1,2-ethanediol, 1,3-propanediol, 1,4-butanediol, and 1,5-pentandiol. Meanwhile, the other alkanediols (1,2-propanediol and 1,3-butanediol) possesses both primary and secondary hydroxyl groups. The measured data were coherently analyzed by the conventional methods, leading to different excess values. The calculated excess quantities indicate the existence of hydrogen-bonding network in the studied systems. The excess values of relative permittivity, molar volume, and Kirkwood correlation factors were found to be negative for all of the binary mixtures, suggesting the formation of multimer structures, the reduction of the effective dipole moments, and the opposite alignment of dipoles in the mixtures. In order to support the experimental data, theoretical calculations were performed using density functional theory (DFT). The optimization of the structures were performed by the B3LYP/6-311G (d,p) DFT level.

中文翻译：

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环戊酮-烷二醇体系：氢键配合物形成的实验和理论研究

这项研究提出了分子相互作用和分子有序化对在298.15 K和101.3 kPa下含有几种链烷二醇和对称环酮（环戊酮）的二元混合物的理化性质和过量值的影响。因此，确定了链烷二醇的介电常数，密度和折射率的实验值–在整个摩尔分数范围内的环戊酮体系。一系列各自具有两个伯羟基的直链伯链烷二醇是1,2-乙二醇，1,3-丙二醇，1,4-丁二醇和1,5-戊二醇。同时，其他链烷二醇（1,2-丙二醇和1,3-丁二醇）同时具有伯羟基和仲羟基。通过常规方法对测量数据进行连贯分析，得出不同的过剩值。计算出的过量表明在研究的系统中存在氢键网络。发现所有二元混合物的相对介电常数，摩尔体积和柯克伍德相关因子的过量值均为负值，表明形成了多聚体结构，降低了有效偶极矩，以及混合物中偶极子的相反排列。为了支持实验数据，使用密度泛函理论（DFT）进行了理论计算。结构的优化是通过B3LYP / 6-311G（d，p）DFT水平进行的。