Calorimetric and Structural Studies of Tetrabutylammonium Bromide Ionic Clathrate Hydrates

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• 作者：Tatyana V. Rodionova ; Vladislav Yu. Komarov ; Galina V. Villevald ; Tamara D. Karpova ; Natalia V. Kuratieva ; Andrey Yu. Manakov
• 刊名：Journal of Physical Chemistry B
• 出版年：2013
• 出版时间：September 12, 2013
• 年：2013
• 卷：117
• 期：36
• 页码：10677-10685
• 全文大小：570K
• 年卷期：v.117,no.36(September 12, 2013)
• ISSN：1520-5207

文摘

In the present work, characteristic properties of tetrabutylammonium bromide (TBAB) ionic clathrate hydrates structures were studied by single-crystal X-ray structure analysis. The structures of three different tetragonal TBAB ionic clathrate hydrates that were formed in our experiments were based on the same water lattice of tetragonal structure I (TS-I) differing in the ways of including bromide anions and arranging tetrabutylammonium cations. We demonstrated that (1) Br^{鈥?/sup> can be included into the water lattice, replacing two water molecules, (2) the butyl group of the cation can be inserted not only in large T and P cavities but also in small D cavities of the water lattice TS-I, and (3) one of the reasons for polytypism of ionic clathrate hydrates on the basis of TS-I is the occurrence of alternative modes of arrangements of four-compartment cavities in adjacent layers of the water framework. The compositions of three TBAB ionic clathrate hydrates TBAB路38.1H₂O, TBAB路32.5H₂O, and TBAB路26.4H₂O were determined by chemical analysis, and their enthalpies of fusion were measured by differential scanning calorimetry (DSC). From the obtained results, the enthalpies of the TBAB hydrate formation from TBAB and water were calculated thermodynamically.}