Ternary liquid–liquid equilibrium data for n-Hexane-Benzene-DES (choline chloride/ethylene glycol, choline chloride/glycerol, choline chloride/urea) at 303 K and 101.3 kPa

Abstract

In this study, deep eutectic solvents (DESs) were prepared using choline chloride as hydrogen bond acceptor (HBA) and ethylene glycol (EG) or glycerol (GLY) or urea (U) as hydrogen bond donor (HBD) and were evaluated as solvents in the extraction of benzene from n-hexane. Six of such solvents were prepared using different molar ratios of HBA: HBD and code named DES1, DES2, DES3, DES4, DES5 and DES6. Liquid–liquid equilibria (LLE) data for the ternary systems of n-hexane-benzene-DESs were measured at 303 K and 101.3 kPa. Solubility data and mutual solubilities between n-hexane and DES were measured using the traditional cloud point method. The tie lines were obtained using titration and refractive index measurements on both phases (n-hexane phase and DES-phases). The ternary systems exhibit type-1 phase behavior. The Othmer-Tobias and Hands equations were applied to examine the reliability of the LLE data. The tie-line data were correlated using the nonrandom two-liquid (NRTL) and universal quasichemical (UNIQUAC) thermodynamic models, and their corresponding binary interaction parameters were determined. The results show that the maximum separation factors were 31.24, 462.00, 15.24, 37.83, 174.60 and 126.00 for DES1, DES2, DES3, DES4, DES5 and DES6, respectively. The glycerol based DES (DES2 and DES5) show the highest separation factors and thus considered the most suitable for separating benzene from hexane. The regression coefficient for both Othmer-Tobias and Hand equations are higher than 0.99 for all DESs, indicating the reliability and consistency of the data. Both NRTL and UNIQUAC models adequately capture the experimental data.

ASPEN plus simulation of liquid–liquid equilibria data for the extraction of aromatics from waste tyre pyrolysis gasoline using organic and deep eutectic solvents: a comparative study

“…The glycerol-based DES therefore show superior performance as extracting solvent for aromatics (BTX). This is in agreement with the findings of our earlier work [19].…”

“…Other more recent works in this regard include Shekaari et al [14][15][16] and Warrag et al [17]. Drawing from the classification of some chlorine chloride-based DES (Choline chloride/urea, choline chloride/glycerol, choline chloride/ethylene glycol) as polar solvents because of their relatively higher values of the Hildebrand and Hansen solubility parameters compared to molecular solvents and ILs [18], our group recently investigated the performance of these DESs in the extraction of benzene from n-hexane [19].…”

Binary mixtures of choline chloride-based deep eutectic solvents as green extractants for the extraction of benzene from n-hexane

“…To the best of our knowledge, there has not been any study on the effect of mixing DESs on its extraction capacity. Yet, the marked differences between reline, glyceline, and ethaline in their extraction performance for aromatics, as reported in our previous contributions [10,11], suggest a possible synergy for a more suitable extractant.…”

“…The materials used for this investigation are same as enumerated in our previous contribution [10]. Benzene, n-hexane, choline chloride, ethylene glycol, urea, and glycerol were purchased from Sigma-Aldrich (Germany) with a mass fraction purity higher than 0.98.…”

“…They show preferential solvency for aromatics as evident in their promising values of distribution coefficient and selectivity, but are challenged by their higher viscosities as compared to the commonly used organic solvent (sulfolane). In our previous contributions, the superiority of glyceline (choline chloride: glycerol in 1:2 molar ratio), ethaline (choline chloride: ethylene glycol in 1:2 molar ratio), and reline (choline chloride:urea in 1:2 molar ratio) over sulfolane was eloquently demonstrated [10,11]. However, the viscosities of these DESs at 298 K are profoundly higher with the following values: glyceline (281 cP) [12], ethaline (42 cP) [13], and reline (750 cP) [14] as against sulfolane (10.35 cP) [15].…”