Liquid–Liquid Equilibria in Binary Solutions Formed by [Pyridinium-Derived][F₄B] Ionic Liquids and Alkanols: New Experimental Data and Validation of a Multiparametric Model for Correlating LLE Data

Abstract

Experimental solubility data are presented for a set of binary systems composed of ionic liquids (IL) derived from pyridium, with the tetrafluoroborate anion, and normal alcohols ranging from ethanol to decanol, in the temperature interval of 275À420 K, at atmospheric pressure. For each case, the miscibility curve and the upper critical solubility temperature (UCST) values are presented. The effects of the ILs on the behavior of solutions with alkanols are analyzed, paying special attention to the pyridine derivatives, and considering a series of structural characteristics of the compounds involved. Miscibility curves are modeled using, for the first time in a LLE study, an adimensional form of a semiempirical model proposed for the Gibbs excess function, Res. 2010, 49, 406], whose particular form in this work isThe results are compared with those of an extended form of the Non-Random Two-Liquids (NRTL) equation, using temperaturedependent parameters. In both cases, a rigorous procedure is carried out to calculate the LLE data, considering the isoactivity criteria, and a global test to check the phase stability for the solutions studied. The final evaluation of the application with the new equation gave satisfactory results.

Multiproperty modeling for a set of binary systems. Evaluation of a model to correlate simultaneously several mixing properties of methyl ethanoate+alkanes and new experimental data

“…Similarly, an important objective of this research is to provide a detailed explanation of the value of an extended form of the model previously used by the authors [40][41][42][43] which, implemented on excess Gibbs function for multicomponent systems g E = g E (p, T, x 1 ), allows a multiproperty representation of solutions, using the same set of parameters for which we try to obtain optimum values. A correlative procedure must be designed for these theoretical models with a thorough analysis of the goodness of fit of the correlation/representation of surface areas such as those in Fig.…”

“…The correlation is made of the properties with a model and procedure previously used by the authors in other works [40][41][42][43]. The general form of the model, based on Gibbs function, and dependent on three variables, is as follows:…”

“…With an even more simplified form, the model was used for the correlation of LLE data [43] alone. However, since in this work data were available in the literature for several properties of the same system, and also for LLE, we decided to try to carry out global correlations of all the quantities found for each binary system.…”

“…The proposed correlation procedure presents an additional difficulty if we compare it with others described in previous works [42,43] since the modeling of LLE with the function g E = g E (x 1 , p, T) cannot be carried out directly, since experimental values for g E are not available for these equilibria. Hence, the combined correlation is carried out by setting up a two-stage procedure, with the following operational aspects:…”

“…Another part of this work, of a more theoretical nature, focuses on presenting a procedure for the simultaneous treatment of data on different thermodynamic properties for a given binary system with a flexible model already used and whose capacity to solve certain complex cases attempts to be evaluated. In previous works [40,43], different situations were proposed that initially presented obstacles to application of the model but that were resolved oneby-one. The model has been shown to have a good flexibility and can be used to set and meet increasingly complex goals.…”