Department of Chemical and Biomolecular Engineering, University of Notre Dame, 182 Fitzpatrick Hall, Notre Dame, Indiana 46556, USA.
J Phys Chem B. 2010 Aug 19;114(32):10496-501. doi: 10.1021/jp1012736.
Experimental excess enthalpies of ionic liquid and water mixtures in combination with calculated CHELPG atomic charges were used to investigate the interactions between the species in solution. The excess enthalpies of ionic liquids in water were obtained by calorimetry, using a Setaram C80 calorimeter, including temperatures from (313.15 to 348.15) K and the entire range of composition. The ionic liquids investigated all contain the 1-ethyl-3-methylimidazolium cation except one, which has an added hydroxyl group on the cation (1-(2-hydroxyethyl)-3-methylimidazolium cation). The anions investigated are ethylsulfate, methylsulfate, hydrogensulfate, trifluoromethanesulfonate, methanesulfonate, and trifluoroacetate, and these will demonstrate the effect of systematically varying the substituents on the anion. The CHELPG atomic charges on the cations and anions were calculated using the Gaussian 03 program. The CHELPG atomic charges are consistent with the observed trends in excess enthalpy and provide insight into cation/water, anion/water, and cation/anion interactions.
实验测定了离子液体与水混合物的过量焓，并结合 CHELPG 原子电荷计算结果，用于研究溶液中各物质间的相互作用。离子液体在水中的过量焓通过量热法获得，使用 Setaram C80 量热计，测定温度范围为（313.15 至 348.15）K 和整个组成范围。所研究的离子液体均含有 1-乙基-3-甲基咪唑阳离子，除了一种在阳离子上增加了一个羟基（1-(2-羟乙基)-3-甲基咪唑阳离子）。所研究的阴离子为硫酸乙酯、硫酸甲酯、硫酸氢根、三氟甲烷磺酸根、甲烷磺酸根和三氟乙酸根，这将展示系统改变阴离子取代基对其的影响。阳离子和阴离子的 CHELPG 原子电荷使用 Gaussian 03 程序计算。CHELPG 原子电荷与过量焓的观察趋势一致，有助于深入了解阳离子/水、阴离子/水和阳离子/阴离子相互作用。
