环戊酮-甲醇氢键复合物的热力学性质

Thermodynamic properties of cyclopentanone-methanol hydrogen-bonding complexes

测定了常压下环戊酮(CPN)与CH3OH二元混合体系在283.15—333.15 K之间全摩尔分数范围的密度,并基于密度数据计算了该混合体系的超额摩尔体积。其超额摩尔体积在所测定的温度和全摩尔分数范围内均呈负偏差。表明该二元混合体系中分子间的交叉缔合作用强于分子间的自缔合作用。同时采用B3LYP/6-311++G(d,p)方法研究了CPN与CH3OH氢键复合物的氢键结构和性质。经几何优化和振动分析获得了2种稳定的氢键复合物。基于统计热力学方法计算了200.00—800.00 K之间从单体形成氢键复合物的热力学性质变化,结果表明CPN和CH3OH分子间氢键交叉缔合是一个放热、熵减的热力学非自发过程。

The densities of the cyclopentanone （CPN） and methanol binary mixtures were measured in the entire molar composition range at 283.15-333.15 K and atmospheric pressure. From the experimental data the excess molar volumes were calculated. The results show that the excess molar volumes have negative deviation in the entire composition range and at the determining temperatures, which means the association between unlike molecules is stronger than that between the same molecules. The hydrogen-bonding structures and properties of the CPN- methanol hydrogen-bonding complexes were investigated theoretically by using B3LYP/6-311 ＋ ＋ G（ d ,p） method, and two stable hydrogen-bonding complexes were obtained by geometry optimization and vibration analysis. The changes of thermodynamic properties from the monomers to hydrogen-bonding complexes at 200.00-800.00 K were obtained using the statistical thermodynamic method. It reveals that the formation of the CPN-methanol hydrogen- bonding complex is an exothermic, entropy reduced and non-spontaneous thermodynamic process.