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Four different dicyanamide-based ionic liquids (ILs), [Cnmpy][DCA] (n = 4, 6, 8, and 10), were synthesized, characterized, and used to separate ethylbenzene from n-octane. Equilibrium data for the corresponding ternary systems were measured at 313.15 K under atmospheric pressure. A higher selectivity is observed for lower aromatic concentrations in the feed (20% max); this is a key factor in selecting a suitable IL. The distribution ratio and selectivity obtained in this work are comparable to those of commercial solvents. The nonrandom two-liquid model (NRTL) was successfully used to correlate the experimental tie-lines and to calculate the phase compositions of the ternary systems. Moreover, the antimicrobial activities of the ILs were evaluated by examining their 50% effective concentrations (EC50) using the standard microbroth dilution test against four human bacterial pathogens. 1-Butyl 3-methylpyridinium dicyanamide [C4mpy][DCA] was found as the most suitable IL among those investigated because of i...

Chlorophenols (CPs) are synthetic chemicals that are generated and used widely by different industries such as textile, pharmaceutical, metallurgic, oil, and pulp and paper manufacturing. Except water, most of the solvents used in these industries are volatile and toxic. Therefore, there is an imminent need for replacing these solvents by solvents that have less negative impact on the environment. In addition, CPs are considered as hazardous pollutants due to their resistance to biodegradation and persistence in the environment. Their toxic effects are severe including DNA damage, endocrine disruption, cytotoxicity, mutagenicity, and carcinogenicity. Hence, the water contaminated by CPs must be treated before being released to the environment. Ionic liquids (ILs) are molten salts that are liquid below 100 °C, which have been used as solvents for many processes including liquid-liquid extraction and as electrolytes in electrochemical devices. ILs are characterized by negligible vapor pressure and non-flammability. These compounds are liquid over a wide range of temperatures; possess high thermal and chemical stability. ILs are being used as media for many reactions to reduce the negative impact of traditional solvents on the environment. In addition, using ILs as green solvents in water treatment has become a research hotspot. Solubility data of CPs in ILs is important for assessing the potential use of ILs as reaction media and in water treatment, but relevant data for ILs are scarce. To our best knowledge, no solubility data of chlorophenols in ILs were reported in the literature. Thus, in this study, the solubility of 3-chlorophenol (3-CP), 2,5-dichlorophenol (DCP), 2,4,6-trichlorophenol (TCP), and pentachlorophenol (PCP) in six hydrophobic bis(trifluoromethylsulfonyl)imide based ILs at 25 °C, 35 °C and 45 °C was investigated. It was found that the solubility of 3-CP in all studied ILs at 25 °C was greater than 70 wt%, thus the solubility measurements of 3-chlorophenol in the studied IL were stopped at 70 wt% and further measurement was not conducted. The solubility of other CPs in all studied ILs decreased with increasing the number of chlorine atoms in the CP and increased with the increase in temperature, but the degree of increase depended on the structure of both the IL and chlorinated phenol. In general, it was found that the tested chlorophenols have substantial solubility in pyridinium and imidazolium-based ILs. In addition, the non-random two-liquid model (NRTL) and Conductor-like Screening Model for Real Solvents (COSMO-RS) models were applied to predict the solubility of chlorophenols in all ILs used in this study. There was a good quantitative and qualitative agreement between experimental and calculated solubility data in most of the cases.

Separation of styrene from ethylbenzene is challenging because of their close boiling points and similar chemical characteristics. In this study, we utilized three ammonium-based deep eutectic solvents (DESs) with glycols as hydrogen bond donors to separate styrene from ethylbenzene via liquid-liquid extraction at room temperature and atmospheric pressure, with styrene concentration in the feed mixture ranging from (10 to 80) wt%. Consistency of the experimental data was ascertained by Othmer-Tobias and Hand correlations, and the NRTL binary interaction parameters were also validated for thermodynamic consistency. Distribution ratios of styrene were found to be comparable to that obtained using ionic liquids, although the selectivity values were much lower. The ternary liquid-liquid equilibria for the systems {ethylbenzene (1) + styrene (2) + DES (3)} were correlated with the NRTL model and predicted using the COSMO-RS approach. The average RMSD from the experimental data for NRTL correlation is 1.41% and for COSMO-RS prediction is 4.74%.

Removal of nitrogen compounds is an essential process in the fuel processing industry. In this work, the extraction performance of 1-ethyl-3-methylimidazolium methanesulfonate ([Emim][MeSO3]) ionic liquid in removing pyrrole, indoline, pyridine and quinoline from cyclohexane is investigated. The ternary liquid-liquid equilibria for four systems containing [Emim][MeSO3] + pyrrole/indoline/pyridine/quinoline + cyclohexane were predicted using COSMO-RS and validated experimentally at 298.15 K under atmospheric pressure, with feed concentrations of nitrogen compounds ranging from 5 to 50 wt%. Othmer-Tobias and Hand correlations confirmed the consistency of the experimental data. The tie-lines obtained experimentally and predicted with COSMO-RS were in good agreement. Additionally, the non-random two-liquid (NRTL) model was successfully employed to correlate the experimental tie-lines. The effects of basicity of nitrogen compounds toward extraction efficiency were also investigated. The selectivity and distribution ratio results demonstrated the suitability of [Emim][MeSO3] as an extraction solvent for removing nitrogen compounds from fuel. Finally, the multicomponent extraction confirmed the performance of [Emim][MeSO3] for extractive denitrogenation. In all ternary systems investigated in this work, the concentration of cyclohexane in the extract phase was very small and the presence of the IL in the raffinate phase was negligible indicating minimum cross contamination between the extract and raffinate phases.

In this study, the COSMO-RS approach was used to qualitatively and quantitatively screen five choline chloride-based deep eutectic solvents (DESs) to separate the azeotropic binary formed between benzene and either methanol or ethanol. The activity coefficient at infinite dilution was calculated to evaluate the capacity, selectivity, and performance index of each DES. The interactions between the different species were also analyzed by interpreting the σ-profile and σ-potential of each component. Then, three DESs were selected for experimental validation. They were prepared by combining choline chloride with ethylene glycol, levulinic acid, and 1,2-propanediol. The best performance in terms of distribution ratio and selectivity was achieved with choline chloride/ethylene glycol DES with 1:4 molar ratio. The experimental tie-lines were successfully correlated using the NRTL model. Regardless of the system investigated, no DES was found in the raffinate phase, implying minimal cross-contamination. Finally, ...

In this study, the feasibility of twelve different deep eutectic solvents (DESs) in separating olefins from paraffins was investigated. The DESs were prepared by combining choline chloride (ChCl) or tetrabutyl ammonium bromide (TBAB) with six different hydrogen bond donors. The preliminary COSMO-RS screening revealed that TBAB/TEG (1:4) DES has the high performance index (PI) for both systems. This performance was confirmed by experimental tests at 20% molar ratio of olefins in the feed mixture with the twelve DESs. When TBAB is used, the best distribution ratios were obtained for cyclohexane/cyclohexene system, however for hexane/1-hexene system high selectivities were gotten. In comparison with the performance of ionic liquids, TBAB-based DESs showed better distribution ratios and comparable selectivity. For the cyclohexane/cyclohexene system, TBAB-based DESs exhibited high distribution ratios because of their hydrophobic character represented by butyl chain. In the case of hexane/1-hexene system, TBAB-based DESs are more selective to 1-hexene due to the affinity of TBAB chain and positive charge bringing by ammonium group and 1-hexene. The liquid–liquid equilibrium (LLE) was explored for two ternary systems of {hexane (1) + 1-hexene (2) + DES (3) } and {cyclohexane (1) + cyclohexene (2) + DES (3) } at 298.15 K and 101 kPa using TBAB/TEG (1:4) DES. Furthermore, the NRTL model was successfully used to correlate the experimental LLE data and good predictions were obtained with COSMO-RS for both selected systems. Finally, the extraction mechanism was elucidated by applying 1H NMR analysis and no DESs were found in the raffinate phase.

Eutectic solvents (ESs) have been extensively studied in the literature for the purification of fuels. Nevertheless, most studies investigated the extraction of a single type of aromatic from n-alkanes. In this work, aiming to provide insights about the performance of ESs in a process that mimics the multicomponent dearomatization used industrially, a salt-acid-based ES, comprised of methyltriphenyl-phosphonium bromide and acetic acid, was applied in simultaneously extracting toluene, thiophene, quinoline, and pyrrole from n-decane. First, the DES was characterized for its eutectic composition, physicochemical, and critical properties. Then, an initial screening to determine the molecular-level interactions and extraction mechanism were studied experimentally and using COSMO-RS screening charge density profiles and potentials. A physical mechanism was confirmed for the extraction of pyrrole, thiophene, and toluene while for quinoline, an acid-base reaction was the predominant extraction mechanism. The phase diagrams of each impurity were also experimentally determined, predicted using the COSMO-RS model, and correlated using the NRTL model in Aspen Plus. Lastly, a parametric investigation studying the impact of key parameters including stirring time, initial concentration, mixing effects, solvent-to-feed ratio, multi-stage extraction, and repetitive usage of solvent was conducted. On multi-stage extraction, full recovery of pyrrole and quinoline ( ≈ 99.9%) was achieved in only 2-stages, whereas for thiophene and toluene efficiencies of 82.2% and 58.4% were reached after the 5th stage, respectively.

Separation of azeotropic mixtures is a topic of great industrial interest. In this work, liquid-liquid extraction using deep eutectic solvents (DESs) is explored to separate binary azeotropic mixtures of ethanol and n-hexane, n-heptane or n-octane. Ten DESs were screened using the COSMO-RS approach by predicting the activity coefficient at infinite dilution, γ∞ of ethanol and n-alkanes in each DES. Then, three DESs were selected for experimental validation where Tetrabutylammonium bromide/Levulinic acid (TBAB/LA) with a molar ratio (1:2) gave the best extractive performance for all systems. Ternary liquid-liquid extraction experiments were conducted at room temperature with this DES. It was found that the tie-lines of all systems have positive slopes, indicating that a small amount of solvent is required to extract ethanol. Moreover, the distribution ratio and selectivity values are all greater than unity and the DES was not detected in the raffinate phase which indicate minimal cross-contamination between extract and raffinate phases. Finally, COSMO-RS predictions of the ternary tie-lines were in excellent agreement with experimental data, with an average RMSD value of 1.65%. The experimental data were also successfully correlated with NRTL model with an average RMSD value of 1.50%.

The separation of benzene and cyclohexane is considered one of the most challenging processes in the petrochemical industry. For this study, 40 deep eutectic solvents (DESs) were screened by using the COSMO-RS model. The screening was achieved based on a comparison of selectivity, capacity, and the performance index, all derived from the activity coefficient at infinite dilution. In addition, the sigma σ-profile and σ-potential of each component were used to analyse the interactions between the different species during the extraction process. After screening, five DESs were selected for experimental validation. The liquid–liquid extraction process was conducted, and the ternary diagrams were plotted for the selected DESs at 25 °C under atmospheric pressure. The NRTL model was successfully employed to correlate the experimental tie lines. The results revealed that COSMO-RS was a useful tool for screening potential DESs qualitatively. In addition, observations revealed strong agreement between NRTL and the experiment results, with a root mean square deviation of less than unity for all systems. The findings showed that the selected DESs are feasible for use as extracting solvents for this separation, whereby in all systems no trace of DES was found in the cyclohexane layer.

For the practical application of ionic liquids as possible solvents for the removal of thiophenic compounds in the diesel fuel, the liquid–liquid equilibrium (LLE) data of such systems is necessary for the design and optimization of process equipment. In this work, LLE experiments were carried out on four ternary systems consisting of one of two pyrrolidinium or phosphonium-based ionic liquids (IL), one of two sulfur compounds and hexadecane as a representative for diesel fuel. For benzothiophene, the system consisting of the [HMPyrr][TFSI] IL as a solvent possesses the highest solute distribution coefficient (2.754) while a solute distribution coefficient of 3.722 was recorded for dibenzothiophene using the [P4444][MeSO3] as an extraction solvent. The LLE data were fairly correlated with the NRTL model especially at the region of low mole fraction of the sulfur compounds. The data presented in this work can therefore be integrated into process simulators and can be used for preliminary techno-economic evaluation of an ionic liquid-based deep extractive desulfurization of diesel fuel.

This work investigates the use of deep eutectic solvents (DESs) to extract sulfur-based compounds from n-heptane as model diesel compounds. Four DESs were prepared by combining tetrabutylammonium bromide or methyltriphenylphosphonium bromide with ethylene glycol, triethylene glycol, or sulfolane. All DESs showed good ability to extract thiophene with the best extraction efficiency (35%) being observed for the sulfolane-based DES. The extraction efficiency can be further enhanced to reach 98% when five extraction cycles are performed. Moreover, the DESs were easily regenerated using rotary evaporation. In addition,1H NMR analysis is used to elucidate the extraction mechanism. Finally, the COSMO-RS model was used to predict the ternary tie lines for the studied systems and the NRTL model allowed, correlating the experimental data with an average root-mean-square deviation of

Recently, we published the results of screening the performance of 94 deep eutectic solvents (DESs) by COSMO-RS for potential use in the extractive denitrogenation of diesel. In this work and based on our previous predictions, tetrabutylammonium bromide + ethylene glycol and tetrabutylphosphonium bromide + ethylene glycol DESs at molar ratio 1:2 were explored experimentally for the removal of pyrrole, pyridine, indoline and quinoline from a model diesel compound, n-hexadecane. Ternary (liquid + liquid) equilibrium experiments were conducted at room temperature with nitrogen concentrations in the feed ranging from (5 to 50) wt%. 1H NMR spectroscopy was used for compositional analysis of the extract and raffinate phases. No amount of the solvent in the raffinate phases was detected; indicating minimal cross contamination. Also, it was found that all systems exhibit Type I phase behavior with positive slopes which indicate that small amount of solvents is required to remove the nitrogen compounds. Moreover, the distribution ratio and selectivity values are all greater than unity with higher values reported for non-basic nitrogen compounds. COSMO-RS predictions of the ternary tie lines were in good agreement with experimental data with average RMSD value of 2.51%. The experimental data were also well correlated with NRTL model with average RMSD value of 0.60%.

In our previous work, we showed that phosphonium-based deep eutectic solvents (DESs) are good candidates for the extractive denitrogenation of oil fuels. In particular, pyridine was successfully extracted from n-hexane and n-heptane via liquid-liquid extraction. The extraction using ‘methyltriphenylphosphonium bromide and ethylene glycol’ DES yielded high distribution ratios and selectivities of pyridine. In this work, two phosphonium-based DESs were prepared, the first one was a “binary DES” composed of methyltriphenylphosphonium bromide and glycerol and the second one was a “ternary DES” composed of methyltriphenylphosphonium bromide, glycerol, and ethylene glycol. One objective was to assess the extraction properties of the DESs for pyridine from n-alkanes. Another objective of this work was to study the influence of n-alkane chain length on the extraction performance. Thus, the oil models selected were n-hexane/pyridine, n-heptane/pyridine, and n-octane/pyridine. First, the prepared DESs were characterized for their water content, density, viscosity, and the degradation temperatures. Then the solubility of n-hexane, n-heptane, n-octane, and pyridine in the DESs was measured at 298.2 K and 1.01 bar. Afterward, the liquid-liquid equilibrium (LLE) data of the pseudo-ternary systems {n-alkane + pyridine + DES} were determined at a temperature of 298.2 K and a pressure of 1.01 bar. The consideration of a pseudo-ternary system was validated by showing that none of the DES constituents appears in the n-alkane-rich phase “the raffinate”. The solute distribution ratios and the selectivities were calculated from the experimental LLE data and compared to our previous work and some relevant literature. Furthermore, the LLE data were correlated with the non-random two-liquid (NRTL) model using ASPEN Plus. There was good agreement between the calculated experimental results. Finally, the COnductor like Screening MOdel for Real Solvents (COSMO-RS) model was used to predict the ternary tie lines for the studied systems. Based on the good distribution ratios and selectivities obtained, the studied DESs can be considered as potential solvents for extractive denitrogenation processes.

Separation of benzene and cyclohexane remains a challenging process in petrochemical industry due to their almost similar boiling temperatures. The present work validated the performance of a reportedly benzene-selective ionic liquid (IL), i.e. 1-ethyl-3-methylimidazolium tetrafluoroborate ([C2Mim][BF4]) to extract benzene from its mixture with cyclohexane via liquid–liquid extraction. The ternary liquid–liquid equilibria of benzene+cyclohexane+[C2Mim][BF4] was investigated at 25 °C and under 1 atm with feed concentration of benzene ranging from 10 to 60 wt %. Good agreement was achieved between COSMO-RS prediction and the experimental data for the tie-lines obtained, whereby the root mean square deviation (RMSD) was 2.5%. The non-random two-liquid (NRTL) model was also successfully employed to correlate the experimental tie-lines, whereby the RMSD was 0.5%. The extractive performance of [C2Mim][BF4] was compared with other organic solvents in the literature and a few common ILs employed in our previous work. At equilibrium, IL was not present in the cyclohexane-rich layer, and the molar concentration of cyclohexane in the IL-rich layer was less than 0.01. The results indicated an efficient extraction process as the cross-contamination between the phases was minimal, and relatively less energy was required to recover the IL.

1-Ethyl-3-methylimidazolium ethyl sulfate ([EMIM][EtSO4]), 1-ethyl-3-methylpyridinium ethyl sulfate ([EMPY][EtSO4]) and 1-ethyl-3-methylimidazolium methanesulfonate ([EMIM][MeSO3]) ionic liquids were investigated to remove pyrrole, indoline, pyridine and quinoline nitrogen compounds from n-hexadecane. Twelve sets of ternary liquid–liquid equilibrium experiments were conducted at room temperature and atmospheric pressure with feed concentrations of nitrogen compounds ranging between 5 and 50 wt%. The ternary phase diagrams for all systems show positive slope, indicating that small amount of solvent is sufficient to remove the nitrogen compounds. Based on the values of distribution coefficient and selectivity, all three ionic liquids are potential solvents for removal of nitrogen compounds, but more effective in removing 5-membered compounds (pyrrole, indoline) than 6-membered compounds (pyridine and quinoline). COSMO-RS predictions of the ternary tie-lines were in good agreement with experimental results (RMSD

In this work, the liquid–liquid extraction of toluene from hydrocarbons mixtures (toluene/heptane) was investigated using deep eutectic solvents as solvents. Ethyltriphenylphosphonium iodide as a salt with either ethylene glycol or sulfolane as hydrogen-bond donors (HBDs) were utilized for synthesizing six DESs. (Liquid + liquid) equilibria data were determined experimentally for the ternary system (toluene + heptane + DES) at (30, 40, 50, and 60) °C and atmospheric pressure. Hand correlation was applied to establish the reliability of the experimental data. In many cases the correlation factor is found close to unity which indicates high reliability of the data. The selectivities and distribution coefficients were used to determine the suitability of these DESs as solvents for this extraction process. Higher selectivities than those published for sulfolane as a commercial solvent were observed. The DES made from ethyltriphenylphosphonium iodide and sulfolane at salt:HBD of 1:4 showed the best separation capability at 30 °C. Thus, it was further characterized by measuring its viscosity and refractive index at a range of temperatures to help understand its physical behaviour needed for process design. The non-random two-liquid (NRTL) model was applied successfully to correlate the experimental tie-lines and to calculate the phase compositions of the ternary systems. It has been found that the third non-randomness parameter varies linearly with the HBD number of moles.

In this work, new solvents are introduced to conduct the task of removing aromatic hydrocarbons from the feed stream to ethylene cracker. Liquid–liquid equilibrium (LLE) data for ternary systems of toluene and heptane with two newly introduced deep eutectic solvents (DESs) were estimated experimentally at 40, 50 and 60 °C and atmospheric pressure. The DESs are made from tetrabutylphosphonium bromide as salt and either ethylene glycol or sulfolane as hydrogen bond donor (HBD). The reliability of the LLE data were ascertained by applying the Othmer–Tobias and Hand correlations. The non-random two liquid (NRTL) model was used to correlate the experimental tie-lines and to calculate the phase compositions of the ternary systems. The results showed a very good agreement between calculated and experimental compositions. Further LLE data are presented to estimate the improvement of the separation by changing the salt:HBD molar ratio used to synthesize the DES at 30, 40, 50 and 60 °C. This work illustrates the possibility of applying these two DESs as solvents for this extraction task.

Separation of benzene and cyclohexane is a challenging process in petrochemical industry due to the difficulty to separate them by a simple distillation. Recognizing ionic liquid as a potential alternative, this work investigated the performance of 1-butyl-3-methylimidazolium acetate ([C4Mim][Ac]) as an extracting solvent in the separation of benzene and cyclohexane via liquid–liquid extraction. The ternary liquid-liquid equilibria for this IL with benzene and cyclohexane was investigated at 25°C and 1 atm, with feed concentration of benzene ranging from 10 to 60 wt %. Good agreement was achieved for the tie-lines obtained from the COSMO-RS model and experimental data. The NRTL model was successfully employed to correlate the experimental tie lines. The performance of [C4Mim][Ac] was compared with organic solvent and other ILs reported in literature. The selectivity and distribution ratio of benzene were in the range of 4.17–5.47 and 0.51–0.72, respectively. At equilibrium, no IL was present in the cyclohexane layer and the concentration of cyclohexane in the IL layer was very low. This observation indicated that there was minimum cross-contamination between the phases and less energy was required for solvent recovery.

In this work, we have investigated the possibility of using low cost ionic liquid analogues, namely deep eutectic solvents (DESs), for the liquid-liquid extraction of ethylbenzene from n-octane. The DESs used in this work were synthesized from ammonium salt with ethylene glycol and sulfolane as complexing agents. Equilibrium data for the ternary system consisting of ethylbenzene, n-octane and the DES were measured at 25°C and atmospheric pressure. The solvent formed by mixing tetraethyl-ammonium p-toluenesulfonate and sulfolane showed the best performance, i.e., the highest distribution ratio and selectivity. The complexing agents were not found in the raffinate phase. This will facilitate the separation process protocol and hence reduce the cost of the process. Finally, the experimental data was satisfactorily correlated using the NRTL model, showing that this classical model can easily be adopted with systems such as DESs.

Separation of aromatics from aliphatics is challenging because of the close range of their boiling points and the formation of several combinations of azeotropes. Until now, no feasible separation process is available for aromatic concentrations below 20 wt%. In this work, we have investigated the possibility of using selected Deep Eutectic Solvents (DESs) for the liquid-liquid extraction of aromatics. DESs have emerged as green solvents that may offer several industrial alternatives. The DESs used in this work were synthesized from ammonium salt with ethylene glycol, lactic acid and sulfolane as Hydrogen Bond Donor (HBD). Equilibrium data for the ternary system consisting of ethylbenzene and n-octane with all DESs were measured at 25°C and atmospheric pressure. The results showed comparable distribution ratio and selectivity with commercial solvents. The absence of the HBD in the hydrocarbon layer, means the reduction of the number of separation stages. In addition, the Non-Random Two Liquid (NRTL) model was successfully used to correlate the experimental tie-lines and to calculate the phase compositions of the ternary systems.