Physical properties of aqueous mixtures of N-methyldiethanolamine (MDEA) and ionic liquids

In the present study, experiments have been conducted to measure the surface tension and heat capacity of aqueous mixtures of N-methyldiethanolamine (MDEA) and ionic liquids (ILs) at atmospheric pressure. Two types of ILs, 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4] and 1-buty1-3-methylimidazolium dicyanamide [bmim] [DCA]) were used in these experiments. The surface tension was found to decrease with increasing temperature and ionic liquid concentration. Furthermore, the heat capacity of the mixtures increases with decreasing ionic-liquid concentration and increasing temperature. Linear equations were used to correlate the measured surface tension values, quadratic equations were applied to correlate the heat capacity at different compositions and temperatures. (C) 2013 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.