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![7-Ethane/ethylene ideal selectivity versus ethylene absorption (left-hand side) and propane/propylene ideal selectivity versus propylene absorption (right-hand side) in the ionic liquids: , [C 1 C 2 Im][NTf 2 ]; , [C 1 C 4 Im][NTf 2 ]; , [C 1 (C 3 H 5 CH 2 )Im][NTf 2 ]; ▲, [C 1 C 6 Im][NTf 2 ]*; , [C 1 (CH 2 C 6 H 5 )Im][NTf 2 ]; , [C 1 C 3 CNIm][NTf 2 ]*; ▲, [(C 3 CN) 2 Im][NTf 2 ]*; ▼, [C 1 C 2 Im][PF 6 ]; , [C 1 C 4 Im][PF 6 ]*; ▼, [C 1 C 2 Im][DCA]; ▼, [C 1 C 4 Im][BF 4 ]; , [C 1 C 2 Im][CF 3 SO 3 ]; , [P 4444 ][TMPP]; ▲, [P (14)666 ][TMPP]; ▲, [C 1 C 4 Pyrr][NTf 2 ] and , [C 1 C 6 Pyr][NTf 2 ] at 313 K. * at 303 K for the ethane/ethylene separation.](profile/Leila-Moura/publication/305488598/figure/fig20/AS:614372812546056@1523489301980/Ethane-ethylene-ideal-selectivity-versus-ethylene-absorption-left-hand-side-and.png)
7-Ethane/ethylene ideal selectivity versus ethylene absorption (left-hand side) and propane/propylene ideal selectivity versus propylene absorption (right-hand side) in the ionic liquids: , [C 1 C 2 Im][NTf 2 ]; , [C 1 C 4 Im][NTf 2 ]; , [C 1 (C 3 H 5 CH 2 )Im][NTf 2 ]; ▲, [C 1 C 6 Im][NTf 2 ]*; , [C 1 (CH 2 C 6 H 5 )Im][NTf 2 ]; , [C 1 C 3 CNIm][NTf 2 ]*; ▲, [(C 3 CN) 2 Im][NTf 2 ]*; ▼, [C 1 C 2 Im][PF 6 ]; , [C 1 C 4 Im][PF 6 ]*; ▼, [C 1 C 2 Im][DCA]; ▼, [C 1 C 4 Im][BF 4 ]; , [C 1 C 2 Im][CF 3 SO 3 ]; , [P 4444 ][TMPP]; ▲, [P (14)666 ][TMPP]; ▲, [C 1 C 4 Pyrr][NTf 2 ] and , [C 1 C 6 Pyr][NTf 2 ] at 313 K. * at 303 K for the ethane/ethylene separation.
Source publication
The goal of this research was to synthesize, characterize and study the potential of selected ionic liquids as solvents for the separation of ethane and ethene. The influence on ethene absorption of the presence of three different metallic cations, lithium (I), nickel (II) and copper (II) in an ionic liquid was also studied.
The selected ionic liqu...
Citations
... The proficiency of the systems in terms of Tc changes is almost the Fig. 14. A review of the literature shows that various factors, such as enthalpy of adsorption, entropic effects, solvent-solvent interactions, etc. affect the gas solubility in different liquids, especially ILs [79,80]. In experimental studies, Henry's constants are usually utilized to inquire the phase behaviour of gas-liquid systems [81,82]. ...
... Therefore, the effect of changes in pressure, temperature, type of anion and cation on solubility is affected by changes in enthalpy and entropy. In other words, the endothermic or exothermic nature of the dissolution process, which is also depends on the interactions between the gas and the ionic liquid, affects how the gas solubility changes with the increase of each of the mentioned parameters 84 . ...
... Generally, the dependency of solubility on temperature is thermodynamically related to the enthalpy of dissolution. For example, in exothermic processes (such as dissolution of CO 2 in ILs) the solubility of the gas decreases with increasing temperature, and in endothermic processes (such as dissolution of N 2 in ILs) the increase in temperature increases the solubility 83,84 . Also, increasing the alkyl chain length increases the solubility of hydrocarbons in ILs 87 . ...
... Also, increasing the alkyl chain length increases the solubility of hydrocarbons in ILs 87 . The reason for this subject is the increased entropy of solvation for ILs 84 . According to Fig. 17, although increasing the alkyl chain length does not show a specific trend in ethane solubility in the proposed systems, increasing the temperature has reduced the ethane solubility in the proposed systems. ...
Ionic liquids (ILs) have emerged as suitable options for gas storage applications over the past decade. Consequently, accurate prediction of gas solubility in ILs is crucial for their application in the industry. In this study, four intelligent techniques including Extreme Learning Machine (ELM), Deep Belief Network (DBN), Multivariate Adaptive Regression Splines (MARS), and Boosting-Support Vector Regression (Boost-SVR) have been proposed to estimate the solubility of some gaseous hydrocarbons in ILs based on two distinct methods. In the first method, the thermodynamic properties of hydrocarbons and ILs were used as input parameters, while in the second method, the chemical structure of ILs and hydrocarbons along with temperature and pressure were used. The results show that in the first method, the DBN model with root mean square error (RMSE) and coefficient of determination (R2) values of 0.0054 and 0.9961, respectively, and in the second method, the DBN model with RMSE and R2 values of 0.0065 and 0.9943, respectively, have the most accurate predictions. To evaluate the performance of intelligent models, the obtained results were compared with previous studies and equations of the state including Peng–Robinson (PR), Soave–Redlich–Kwong (SRK), Redlich–Kwong (RK), and Zudkevitch–Joffe (ZJ). Findings show that intelligent models have high accuracy compared to equations of state. Finally, the investigation of the effect of different factors such as alkyl chain length, type of anion and cation, pressure, temperature, and type of hydrocarbon on the solubility of gaseous hydrocarbons in ILs shows that pressure and temperature have a direct and inverse effect on increasing the solubility of gaseous hydrocarbons in ILs, respectively. Also, the evaluation of the effect of hydrocarbon type shows that increasing the molecular weight of hydrocarbons increases the solubility of gaseous hydrocarbons in ILs.
... The influence in ethylene solubility of the presence of three different cations, lithium (I), nickel (II) and copper (II) in [C 1 (CH 2 C 6 H 5 )Im][NTf 2 ] ionic liquid was studied by Moura [30]. The authors concluded that cations such as lithium and nickel slightly affect the solubility of ethylene. ...
The functionalization of the side chains on the cation or the anion of an ionic liquid is a common approach to tailor its properties for different processes including the separation of gases. In this paper, we present the current state of the art concerning the usage of ionic liquids for hydrocarbon separations. We also show how the functionalization of ionic liquids or the appropriate anion/cation combinations can contribute to the increase of the performance of the ionic liquids for the separation of gaseous hydrocarbons - either by improving the capacity of the ionic liquid to absorb a given gas or by increasing the selectivity towards a particular hydrocarbon. Original results concerning the usage of olefin-complexing metal salts of lithium (I), nickel (II) and copper (II) dissolved in ionic liquids for selectively absorbing light olefins are presented. It is observed that the absorption capacity of an imidazolium-based ionic liquid is doubled by the addition of a copper (II) salt. This result is compared with the effect of the functionalization of the ionic liquid and the advantages and difficulties of the two approaches are analyzed.
Solutions of [Bmim][BF4] ionic liquid (IL) mixed with three alkali metal tetrafluoroborate salts, i.e. LiBF4, NaBF4 and KBF4, were used to capture and separate CO2/CH4 at 303.15, 313.15 and 323.15 K under different pressures ranged from 500 to 3000 kPa. CO2 solubility in three alkali metal doped solutions decreases with the increase of temperature and decreasing pressure. High concentration of alkali metal salts does not show a very improvement for CO2 absorption, and even reduce CO2 capture instead in the presence of high concentration of LiBF4 in ionic liquid. Unexpectedly, KBF4 has the least solubility in [Bmim][BF4] and LiBF4 dissolved most in [Bmim][BF4] ionic liquid. On the contrary, the solubility of metal complex ionic liquids to CH4 decreased after adding alkali metal salts of any concentration. 0.01 mol·L⁻¹ KBF4-IL showed the best CO2/CH4 solubility selectivity at 303.15 K, up to 54.5. On a basis of Quantum chemical calculations, binding energies between metal-doped ionic liquids and CO2/CH4 were calculated, following an order of KBF4-IL-CO2 > NaBF4-IL-CO2 > LiBF4-IL-CO2 and LiBF4-IL-CH4 > NaBF4-IL-CH4 > KBF4-IL-CH4, which is consistent with the experimental results. [BF4]⁻ anions are approaching the metal ions and the larger metal cations, i.e. Na⁺ and K⁺, have longer distances with the anions than Li⁺, which explains the reason of reduced CO2 solubility when Li⁺ becomes more. Generally, high concentration of metal ions in ionic liquids are inferior for CO2 absorption because of the association of MBF4 with the ionic liquid. Therefore, the results of this paper can lay a theoretical foundation for CO2/CH4 capture separation.
