Vaporization and Formation Enthalpies of 1-Alkyl-3-methylimidazolium Tricyanomethanides

详细信息    查看全文

• 作者：Vladimir N. Emel鈥檡anenko ; Dzmitry H. Zaitsau ; Sergey P. Verevkin ; Andreas Heintz ; Karsten Vo脽 ; Axel Schulz
• 刊名：Journal of Physical Chemistry B
• 出版年：2011
• 出版时间：October 13, 2011
• 年：2011
• 卷：115
• 期：40
• 页码：11712-11717
• 全文大小：756K
• 年卷期：v.115,no.40(October 13, 2011)
• ISSN：1520-5207

文摘

Thermochemical studies of the ionic liquids 1-ethyl-3-methylimidazolium tricyanomethanide [Cub>2ub>MIM][C(CN)ub>3ub>] and 1-butyl-3-methylimidazolium tricyanomethanide [Cub>4ub>MIM][C(CN)ub>3ub>] have been performed in this work. Vaporization enthalpies have been obtained using a recently developed quartz crystal microbalance (QCM) technique. The molar enthalpies of formation of these ionic liquids in the liquid state were measured by means of combustion calorimetry. A combination of the results obtained from QCM and combustion calorimetry lead to values of gaseous molar enthalpies of formation of [Cub>nub>MIM][C(CN)ub>3ub>]. First-principles calculations of the enthalpies of formation in the gaseous phase for the ionic liquids [Cub>nub>MIM][C(CN)ub>3ub>] have been performed using the CBS-QB3 and G3MP2 theory and have been compared with the experimental data. Furthermore, experimental results of enthalpies of formation of imidazolium-based ionic liquids with the cation [Cub>nub>MIM] (where n = 2 and 4) and anions [N(CN)ub>2ub>], [NOub>3ub>], and [C(CN)ub>3ub>] available in the literature have been collected and checked for consistency using a group additivity procedure. It has been found that the enthalpies of formation of these ionic liquids roughly obey group additivity rules.