A New Method for the Determination of Vaporization Enthalpies of Ionic Liquids at Low Temperatures

详细信息    查看全文

• 作者：Sergey P. Verevkin ; Dzmitry H. Zaitsau ; Vladimir N. Emel虁yanenko ; Andreas Heintz
• 刊名：Journal of Physical Chemistry B
• 出版年：2011
• 出版时间：November 10, 2011
• 年：2011
• 卷：115
• 期：44
• 页码：12889-12895
• 全文大小：812K
• 年卷期：v.115,no.44(November 10, 2011)
• ISSN：1520-5207

文摘

A new method for the determination of vaporization enthalpies of extremely low volatile ILs has been developed using a newly constructed quartz crystal microbalance (QCM) vacuum setup. Because of the very high sensitivity of the QCM it has been possible to reduce the average temperature of the vaporization studies by approximately 100 K in comparison to other conventional techniques. The physical basis of the evaluation procedure has been developed and test measurements have been performed with the common ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide [C₂mim][NTf₂] extending the range of measuring vaporization enthalpies down to 363 K. The results obtained for [C₂mim][NTf₂] have been tested for thermodynamic consistency by comparison with data already available at higher temperatures. Comparison of the temperature-dependent vaporization enthalpy data taken from the literature show only acceptable agreement with the heat capacity difference of 鈭?0 J K^鈥? mol^鈥?. The method developed in this work opens also a new way to obtain reliable values of vaporization enthalpies of thermally unstable ionic liquids.