Positive and Negative Contributions in the Solvation Enthalpy due to Specific Interactions in Binary Mixtures of C1鈥揅4 n-Alkanols and Chloroform with Butan-2-one

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• 作者：Mikhail A. Varfolomeev ; Ilnaz T. Rakipov ; Boris N. Solomonov ; Piotr Lodowski ; Wojciech Marczak
• 刊名：Journal of Physical Chemistry B
• 出版年：2015
• 出版时间：June 25, 2015
• 年：2015
• 卷：119
• 期：25
• 页码：8125-8134
• 全文大小：450K
• ISSN：1520-5207

文摘

In the paper, results of calorimetric measurements, IR spectra, and calculated ab initio stabilization energies of dimers are reported for binary systems butan-2-one + (methanol, ethanol, propan-1-ol, butan-1-ol, and chloroform). Changes in the total enthalpy of specific interactions due to dissolution of butan-2-one in the alcohols, calculated using equations derived in previous works, are positive. That results from the endothermic breaking of the O鈥擧路路路O鈥擧 bonds not completely compensated by the exothermic effects of formation of the O鈥擧路路路O鈺怌 ones. Moreover, the concentration of nonbonded molecules of butan-2-one is significant even in dilute solutions, as is evidenced by the shape of the C鈺怬 stretching vibrations band in the IR spectra. Apart from that, the spectra do not confirm 1:2 complexes in spite of two lone electron pairs in the carbonyl group of butan-2-one capable of forming the hydrogen bonds. The changes in enthalpy of specific interactions are negative for dilute solutions of alcohols and chloroform in butan-2-one and of butan-2-one in chloroform, because no hydrogen bonds occur in pure butan-2-one. The experimental results are positively correlated with the enthalpies estimated from the ab initio energies using a simple 鈥渃hemical reaction鈥?approach.