Experimental thermodynamic properties of 1-butyl-2-methylpyridinium tetrafluoroborate [b2mpy][BF4] with water and with alkan-1-ol and their interpretation with the COSMO-RS methodology

Abstract

This work provides experimental data on liquid-liquid equilibria in the range 288-328 K and data of Hm E and Vm E at temperatures of 298.15 and 318.15 K, for binary mixtures corresponding to 1-butyl-2-methylpyridinium tetrafluoroborate, [b2mpy][BF 4], with alkanols (methanol to pentan-1-ol) and water. The [b2mpy][BF4] is completely miscible in water, and all the mixtures give positive values of Hm E and Vm E, giving increasing values of excess quantities with temperature. For mixtures with alkanols, values of Hm E > 0 are obtained with Vm E < 0 and (dVm E /dT) p > 0. Experimental data are correlated with a suitable equation and are presented together with those obtained in previous works for another two isomers, [b3mpy][BF4] and [b4mpy][BF4], and the properties of all of them are compared and discussed along with their behavior. The quantum-chemical method COSMO-RS is applied for the first time to predict excess properties of these mixtures containing ionic liquids, and the results show a significant contribution of hydrogen bond interactions in the behavior of the mixtures studied here, generically referred to as [bXmpy][BF4] (X ) 2, 3, 4) + H2O or + CvH2v+1(OH) (v = 1-5). © 2009 American Chemical Society.