Correlation of three-liquid-phase equilibria involving ionic liquids

Abstract

The difficulty of achieving a good thermodynamic description of phase equilibria is finding a model that can be extended to a large variety of chemical families and conditions. This problem gets worse in the case of systems containing more than two phases or involving complex compounds such as ionic liquids. However, there are interesting applications that involve multiphasic systems, and the promising features of ionic liquids suggest that they will play an important role in many future processes. In this work, for the first time, the simultaneous correlation of liquid-liquid and liquidliquid-liquid equilibrium data for ternary systems involving ionic liquids has been carried out. To that end, the phase diagram for the system water + [P 6 6 6 14 ][DCA] + hexane has been determined at 298.15 K and 323.15 K and atmospheric pressure. The importance of this system lies in the possibility of using the surface active ionic liquid to improve surfactant enhanced oil recovery methods. With those and previous measurements, thirteen sets of equilibrium data of ternary systems water + ionic liquid + oil have been correlated. The isoactivity equilibrium condition, using the NRTL model, and some pivotal strategies are proposed to correlate these complex systems.Good agreement has been found between experimental and calculated data in all the regions (one triphasic and two biphasic) of the diagrams. The geometric aspects related to the Gibbs energy of mixing function obtained with the model, together with the minor common tangent plane equilibrium condition, are valuable tools to check the consistency of the obtained correlation results.

Application of nature‐inspired algorithms with generalized Pitzer‐Debye‐Hückel (PDH) refinement for liquid liquid equilibria (LLE) correlation in cyclic di‐ether systems

“…Alternatively, the use of a suitable objective function coupled with a good optimization algorithm is generally preferred for generating the required binary interaction parameters. Commonly used optimization techniques include gradient-based methods such as the generalized reduced gradient (GRG) method used by Rodriguez-Escontrela et al 28 In this context, the use of evolutionary metaheuristic algorithms such as genetic algorithm (GA), differential evolution (DE), etc. and nature-inspired metaheuristic algorithms such as particle swarm optimization (PSO), firefly algorithm (FA), cuckoo search (CS), etc.…”

Multiscale Exploration and Experimental Insights into Separating Neutral Heterocyclic Nitrogen Compounds Using [emim][NO3] as an Extractant

“…24,29,[55][56][57][58][59][60][61] The LLE measurements procedure and analysis are presented in detail in Part 2 in the Supporting Information. Furthermore, the NRTL model was used to regress the tie-line data that were determined, and the recognized Graphical User Interface (GUI-MATLAB) raised by Reyes-Labarta [62][63][64][65] was adopted to evaluate the experimental tie-line data.…”

Equilibria and correlation of systems involving 1-hexyl-3-methylpyridinium trifluoromethanesulfonate

“…More details can be seen in a previous paper. 11 The optimisation of the NRTL model parameters was carried out using the GRG (Generalized Reduced Gradient) nonlinear method with the objective function dened as:…”

“…Some phase diagrams involving three liquid-phase systems can be found in literature aimed at the proposal of ILs as surfactants 10,11 or co-surfactants 12 in EOR. In addition, Hejazifar et al 7 highlighted the advantages of the use of surfactant ILs with water and oil to form stable microemulsions as media of catalytic reactions.…”

“… 19 The NRTL model was also proposed to simultaneously correlate the different immiscible regions found in these systems. 11 To that aim, some strategies were suggested to successfully apply the isoactivity algorithm. No modelling was found in literature for more complicated systems, for instance those that contain not only equilibria of liquid but also solid phases.…”