Nonrandom Two-liquid Activity Coefficient Models Research Articles

CO2 solubility and amine volatility data for low-concentration solutions of MEA, AMP, PZ and CESAR-1 blend (AMP/PZ)

Water-wash section(s) effectively reduce amine compound emissions in amine-based carbon capture processes. Reliable predictions of the behavior of these emission control technologies depend on detailed understanding of the vapor-liquid equilibrium (VLE) of water wash system. However, existing vapor-liquid equilibrium data in the literature focus primarily on solvent-like amine concentrations in amine–CO2–H2O systems; hence, new low-concentration VLE data are needed. In this work, the CO2 solubility in low-concentration solutions of monoethanolamine (MEA), piperazine (PZ), 2-amino-2-methyl-1-propanol (AMP), and AMP/PZ blend (CESAR-1) was investigated for temperatures between 303 and 353 K at atmospheric pressure. Additionally, amine volatility measurements for CO2-loaded low-concentration solutions of MEA, PZ, AMP and CESAR-1 were performed in the range of 313–373 K and 8–96 kPa. Overall, the data show that the CO2 partial pressure increases with increasing CO2 loading and temperature. Similarly, the amine partial pressure increases with increasing pressure and temperature. The new experimental data were compared with two existing VLE models using electrolyte non-random two-liquid activity coefficient models to evaluate the ability of the latter to predict vapor-liquid equilibrium behavior. Both CO2 solubility and amine volatility predictions by the models tend to show significant deviations. The comparison highlight the need for such low-concentration data for all systems studied. This data shall serve to improve existing water-wash modeling tools.

Measurement and modelling of vapor–liquid phase equilibrium of 1,1-difluoroethane (R152a) + 1,1,2,3,3,3-hexafluoro-1-propene (R1216) at temperatures ranging from 283.15 K to 313.15 K

Compared to pure refrigerants, mixed refrigerants can effectively fulfill the demands of high efficiency, safety, and environmental preservation. An efficient mixture can be created by combining environmentally safe and non-combustible refrigerants with low global warming potential (GWP) and high latent heat hydrofluorocarbons (HFCs) in precise ratios. For this investigation, an experimental apparatus was built to obtain vapor–liquid equilibrium (VLE) data for the R152a + R1216 mixture within temperatures of 283.15 to 313.15 K. To depict the VLE characteristics of the binary systems, the Peng-Robinson (PR) equation of state (EoS) was utilized with the van der Waals (vdW) mixing rule. And to compare, the Huron and Vidal first-order (HV) and the Wong-Sandler (WS) mixing rules were utilized alongside the PR EoS and the non-random two-liquid (NRTL) activity coefficient model to correlate the acquired data. The findings indicated that the models showed strong concurrence with the empirical data. The binary mixture displays a near-azeotropic phenomenon when the mole fraction of R152a is below 0.65. The azeotropic point is fall within the experimental temperature range when the R152a liquid-phase has a mole fraction between 0.3069 and 0.4104.

The performance of [Emim]Br/H2O as a working pair in the absorption refrigeration system

The energy efficiency of the single-effect absorption refrigeration systems (ARS) using ionic liquid (IL) [Emim]Br as an absorbent and water as a refrigerant is evaluated in this study. The thermodynamic properties of the mixture, such as vapor pressures and excess enthalpies, are calculated using the non-random two-liquid (NRTL) activity coefficient model. The coefficient of performance (COP) is estimated with fixed temperatures for the evaporator, absorber, condenser, and generator, set at 10, 30, 40, and 100 °C, respectively. It is found that the COP of the single-effect ARS using [Emim]Br-H2O as the working pair is about 0.8, which is slightly lower than that obtained with LiBr-H2O (0.83), but much higher than that of H2O-NH3 (0.65) systems. The effect of generator temperature on COP has the same trend as that of other IL working pairs. The influence of each component temperature on the system’s performance is investigated, and it is found that the single-effect ARS performs very well under different conditions with [Emim]Br - H2O as the working pair.

Vapor-liquid equilibrium data and performance analysis on binary mixture of R32 and R1216 for residential air condition system

In order to accurately evaluate the performance of R32 and unsaturated fluorinated olefins (HFOs) binary mixtures in residential air condition (RAC) system, the vapor-liquid phase equilibrium (VLE) data of R32 and R1216 binary mixture has been measured with a liquid phase circulation system in the temperature range from 285 to 315 K. The experimental data were correlated by Peng-Robinson (PR) equation of state with Huron-Vidal (HV) mixing rule and non-random two-liquid (NRTL) activity coefficient model. Maximum deviation of the pressure and the mole fraction was 1.38% and 0.013, respectively. The azeotropic behavior was observed for the R32 and R1216 binary mixture when the mole fraction of R32 was around 0.9. The RAC system with standard refrigeration, heating and variable evaporation temperature operating condition was simulated. The cycle performance of binary mixtures of R32 + R1216, R1234yf and R1234ze(E) at different concentrations was compared. The azeotrope R32/R1216 (molar ratio 0.9/0.1) has an extremely low GWP, the COP, refrigeration/heating capacity per unit volume and condensation pressure close to pure R32, and lower discharge temperature. At the same time, it also has well variable operating conditions performance and can be considered as a drop-in replacement for R32 and R410A in RAC systems.

Extractive distillation process using organic and ionic liquids for the separation of high-GWP refrigerant R410A: A thermodynamic and techno-economic assessment

Reclamation of mixed refrigerants can effectively reduce high global warming potential (GWP) fluorinated gases (F-gases) emissions. Two organic liquids (OLs), Dimethylformamide (DMF) and N, N-Dimethylacetamide (DMAC), were proposed to explore the possibility of separating high GWP and near-azeotropic mixture R410A (50 wt% R32 (difluoromethane) + 50 wt% R125 (pentafluoroethane)) by absorption. Solubilities of R125 in DMF and DMAC were measured from 283.15 to 333.15 K and well correlated with the five-parameter non-random two-liquid (NRTL) activity coefficient model. Ideal selectivity for R32 + R125 of DMAC were higher than that of DMF. Five ionic liquids (ILs) and DMAC on the Pareto front showed good overall performance (integration of capacity and selectivity) for separating R410A, and in the area below the Pareto front, the overall performances of the other solvents were not as good as those from the Pareto front. Subsequently, based on DMAC, 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]), 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([EMIM][Tf2N]) and 1-ethyl-3-methylimidazolium thiocyanate ([EMIM][SCN]), the extractive distillation processes for R410A separation were simulated and evaluated in Aspen Plus. Results showed DMAC was a suitable choice of extractant nowadays due to the lower viscosity and consumption than ILs and the mature corresponding R410A separation process. ILs may be the mainstream extractant for R410A separation in the future, once the price of some ILs such as [BMIM][PF6] can be reduced to $30/kg, the separation process using ILs as extractants will cost less than that of DMAC. Heat pump technology can be further applied for energy integration in the corresponding process of ILs with high ideal selectivity such as [EMIM][SCN]. Thermodynamic and economic analysis of OLs and ILs could provide the key information for the separation of commercial refrigerant R410A, which can also be used as a benchmark to screen more efficient extractants.

Vapor-liquid equilibrium data for binary mixture of 1,1,2,3,3,3-Hexaflfluoro-1-propene (R1216) and trans-1,3,3,3-Tetraflfluoropropene (R1234ze(E)) at temperatures from 275 to 315 K

In this work, the vapor–liquid phase equilibrium (VLE) data of R1234ze(E) and R1216 binary mixtures has been investigated experimentally and theoretically. The VLE data for the binary system of R1234ze(E) + R1216 were measured with a recirculation system at five temperatures range from 275 to 315 K. The experimental results were correlated by Peng-Robinson equation of state combined with Huron-Vidal mixing rule or Wong-Sandler mixing rule and non-random two-liquid activity coefficient model, and van der Waals mixing rule. The calculated values were in well agreement with the experimental results, with the maximum deviations of the pressure and the mole fraction of the vapor phase within 0.87% and 0.016, respectively. The average absolute deviations of the pressure and the mole fraction of the vapor phase between the experimental values and calculated values were 0.35% and 0.005, respectively.

Measurement of vapor-liquid equilibrium for the binary system propene (R1270) + trans-1,3,3,3‑tetrafluoropropene (R1234ze(E)) at temperatures from 288.18 K to 318.18 K

The search for alternative refrigerants that are environmentally friendly and highly efficient has become one of the most urgent and important issues facing the refrigeration industry. R1270 has excellent thermodynamic properties, but its high flammability limits its range of applications. R1234ze(E) is an environmentally friendly refrigerant with negligible flammability though it has the drawback of poor heat transfer performance. R1270 can be blended with R1234ze(E) as a new mixture refrigerant. vapor–liquid equilibrium (VLE) is the basic physical property of mixtures. The vapor–liquid equilibrium data have been measured for the binary system R1270/ R1234ze(E) based on the liquid-phase cycling method at four temperatures (288.15 K, 298.15 K, 308.15 K, 318.15 K). All the experimental data were regressed by the Peng-Robinson (PR) equation of state (EoS) with the Huron–Vidal (HV) mixing rule involving the non-random two-liquid (NTRL) activity coefficient model, and the PR EoS relating to the van der Waals (vdWs) mixing rule. The results show that the predicted values by the two models are in good agreement with the experimental data, and the prediction accuracy of the PR + HV + NTRL model was higher than that of the PR + vdWs model. In addition, azeotropic behaviors of the binary mixture have been found in the measured temperature range.

Vapor-liquid equilibrium of carbon dioxide solubility in a deep eutectic solvent (choline chloride: MDEA) and a mixture of DES with piperazine-experimental study and modeling

In recent decays, many investigators have carried out the CO2 absorption in ionic liquids, but these green solvents are expensive and hard to prepare. In recent years, researchers have introduced deep eutectic (DES) solvents composed of a hydrogen bond donor and a hydrogen bond acceptor. DES melting point is usually lower than the ideal solution of its constituents' components and is in the liquid phase at room temperature. In this work, we have measured CO2 solubility in a deep eutectic solvent composed of choline chloride and methyldiethanolamine (MDEA) in a molar ratio of 1–6. We carried out experiments at 323.15, 333.15, and 343.15 K within the 1–50 bar pressure range. Besides, we added piperazine (Pz) as a physical solvent at 5, 10, and 15 wt% to the DES. Based on the obtained results, we observed enhancing pressure and reducing temperature led to increasing CO2 absorption. Also, increasing piperazine caused to intensify the CO2 absorption in the mixture of the DES + Pz system. Finally, we used a thermodynamic approach for the computation of the vapor–liquid equilibria of the present systems. We applied the Peng-Robinson (PR) equation of state to calculate the gas fugacity coefficient in the vapor phase. The non-random two-liquid (NRTL) activity coefficient model was used to compute the non-ideality of the liquid mixture. The modeling results were in very good agreement with the experimental data.

Isobaric Vapor–Liquid Equilibrium for Ethyl Acetate + Chloroform with Ionic Liquids [EMIM][OAc], [BMIM][OAc], and DMSO + [EMIM][OAc] as Entrainers at 101.3 kPa

Ionic liquid 1-ethyl-3-methylimidazolium acetate ([EMIM][OAc]), 1-butyl-3-methylimidazolium acetate ([BMIM][OAc]), and a mixture of [EMIM][OAc] and dimethyl sulfoxide (DMSO) were used as solvents to separate the maximum boiling azeotropic mixture of ethyl acetate and chloroform. The ternary vapor–liquid equilibrium (VLE) data of ethyl acetate + chloroform + [EMIM][OAc] were measured at 101.3 kPa. The liquid phase is partially soluble when the concentration of ethyl acetate and [EMIM][OAc] is high in the ternary system, and DMSO is employed to enhance the solubility of [EMIM][OAc] in ethyl acetate. Different entrainers were compared by measuring the VLE of ethyl acetate + chloroform + DMSO, ethyl acetate + chloroform + [BMIM][OAc], and ethyl acetate + chloroform + [EMIM][OAc] + DMSO at 101.3 kPa. All of the entrainers can improve the relative volatility of ethyl acetate to chloroform. The salting-out effects of the ILs [EMIM][OAc] and [BMIM][OAc] are significantly greater than that of DMSO. Organic solvent DMSO can enhance the selectivity of [EMIM][OAc] at high ethyl acetate concentration. The effects of the entrainers were analyzed by sigma-profiles. The nonrandom two-liquid (NRTL) activity coefficient model was adopted to correlate the experimental data. The binary interaction parameters of the NRTL equation were obtained, and the correlation results agreed well with experimental results.

Thermodynamic modeling of aqueous lithium salt solutions with association electrolyte nonrandom two-liquid activity coefficient model

The high charge density of lithium ion and the resulting strong association phenomena make thermodynamic modeling of aqueous lithium electrolyte solutions extremely challenging. In this study, the association electrolyte nonrandom two-liquid activity coefficient model of Lin et al. (AIChE J. 2022, 68(2), e17422) is utilized to correlate and predict thermodynamic properties and solubility behavior of aqueous single electrolyte solutions of LiCl, LiBr, LiI, and LiNO3, and their mixed electrolyte solutions. Capturing self-association of water, cross-association of ion and water for hydration, and cross-association of cation and anion for ion-pairing, the association model accurately represents the literature experimental data up to saturation concentrations and at the temperature ranging from 263 K to 523 K. This study further investigated the effect of anions of the lithium salts, and re-confirmed that the order of solution non-ideality as LiI > LiBr > LiCl > LiNO3 because the anions with stronger association strengths are more likely to form ion pairs and thus lower the mean ionic activity coefficients.

Vapor-liquid equilibrium measurements and models for the ternary mixtures of R1234yf + R32 + R125 and R1234yf + R32 + CO2

R1234yf as the environmental friendly refrigerant has a low volumetric refrigeration capacity and light flammability. The refrigerant mixtures are expected to achieve excellent thermophysical performance, safety and environmental performance. The vapor-liquid equilibrium (VLE) is one of the most important properties of the mixtures. In this work, the VLE property of R1234yf + R32 + R125 and R1234yf + R32 + CO2 ternary mixtures were measured along 5 isotherms from 273.15 K to 313.15 K by a recirculation analytical apparatus. The Peng-Robinson (PR) equation of state combined with the van der Waals (vdW) mixing rule (PR + vdW), as well as the PR equation of state combined with the Wong-Sandler (WS) mixing rule and the non-random two-liquid (NRTL) activity coefficient model (PR + WS + NRTL) were used to correlate the VLE data. The model parameters were temperature-dependent and could describe the VLE properties of the ternary and binary subsystems. The results showed that the PR + WS + NRTL model was better than the PR + vdW model. The average absolute relative deviation of pressure (AARD(p)) and average absolute deviation of compositions (AAD(y)) of the PR + WS + NRTL model were 0.4% and 0.003 for R1234yf + R32 + R125 ternary mixture, and were 0.7% and 0.007 for R1234yf + R32 + CO2 ternary mixture. Experimental results and model calculations showed that both the ternary mixtures were zeotropic.

Thermodynamic modeling of adsorption at the liquid-solid interface

Adsorptive separation techniques are significantly energy efficient in comparison to conventional thermal separation techniques such as distillation. Despite extensive research and development activities undertaken for mixed-gas adsorption, the use of adsorption techniques for the separation of multicomponent liquid mixtures is still limited. A major barrier is the lack of accurate adsorption thermodynamic models, which form the scientific foundation of process simulation of such systems, making the translation to industrial scale challenging. In this work, we have rigorously computed the surface excess of adsorption for six binary liquid mixtures on silica gel at 303 K using the frameworks of the generalized Langmuir isotherm (gL) and the adsorbed solution theory (AST). The six binary liquid mixtures were formed by the pair-wise combinations of four components: benzene, 1,2-dichloroethane, cyclohexane, and n-heptane. We have based our calculations by considering simultaneous equilibria of three phases: saturated vapor phase, bulk liquid phase, and adsorbed phase. The composition of the corresponding saturated vapor phase was estimated by the Nonrandom Two-Liquid activity coefficient model and experimental vapor-liquid equilibria data. The activity coefficients of the adsorbed phase, the central issue of multicomponent adsorption thermodynamics, were calculated using the adsorption Nonrandom Two-Liquid activity coefficient model. Devoid of simplifying assumptions, gL and AST provide rigorous thermodynamic frameworks for adsorption equilibria of multicomponent liquid mixtures.

Vapor-liquid equilibrium measurements for binary mixtures of carbon dioxide (CO2) + 2,3,3,3-Tetrafluoroprop-1-ene (R-1234yf) and carbon dioxide (CO2) + 3,3,3-Trifluoropropene (R-1243zf)

The verification experiments of vapor-liquid equilibrium (VLE) for the CO2 + R-1234yf mixture were carried out along three isotherms from (283.15 to 313.15) K by a recirculation-analytical apparatus. The experimental data were in good agreement with the literature, which proved the reliability of the measurement apparatus and method for the binary system containing CO2. The VLE experiments for the CO2 + R-1243zf mixture were carried out along six isotherms from (273.15 to 313.15) K. The standard measurement uncertainty of temperature, pressure and mole fraction were 5 mK, 2.2 kPa and 0.0035, respectively. The Stryjek-Vera version of the Peng-Robinson (PRSV) equation of state combined with the Wong-Sandler (WS) mixing rule and the non-random two-liquid (NRTL) activity coefficient model (PRSV + WS + NRTL) was used to correlate the VLE data. For the CO2 + R-1234yf mixture, the average relative deviation of pressure (ARD(p)) and the average absolute deviation of compositions (AAD(y)) was 0.41% and 0.0028, respectively. For the CO2 + R-1243zf mixture, the ARD(p) and AAD(y) were 0.29% and 0.0021 for the data of this work; the literature data of CO2 + R-1243zf mixture show a systematic positive deviation from the data of this work and the established PRSV + WS + NRTL model.

Solid-liquid equilibrium measurements using DSC for three binary mixtures of 2-methylbenzoic acid + 3-methylbenzoic acid, 2-methoxybenzoic acid + 3-methylbenzoic acid, and N-phenylacetamide + benzamide

This study reports the solid-liquid equilibrium (SLE) data for three binary mixtures of 2-methylbenzoic acid + 3-methylbenzoic acid, 2-methoxybenzoic acid + 3-methylbenzoic acid, and N-phenylacetamide + benzamide. These phase equilibrium data were measured using the Differential Scanning Calorimetry (DSC). The solidus and liquidus temperatures for each binary mixture at various compositions are presented. All three binary mixtures show the simple eutectic behavior. The eutectic temperatures and compositions for these binary mixtures were determined using the fractional transformation method. The fractional transformation is defined as the fraction of the mixture that is liquefied during the heating process using DSC. The fractional transformation data at the eutectic point, denoted as the eutectic fraction, were evaluated from the experimental DSC results over various time intervals during the measurements. A triangular plot of the eutectic fractions against various compositions of a binary mixture effectively illustrated the eutectic point condition. The liquidus curves for each binary system were correlated using the Wilson and NRTL (Non-Random Two-Liquid) activity coefficient models. The optimally fitted model parameters for each binary mixture are presented in this study. Satisfactory correlation results are also demonstrated for all binary systems.

Thermodynamic modeling of aqueous polyelectrolyte solutions with mixed-valent counterions

Thermodynamic modeling of aqueous polyelectrolyte solutions with salts is of significant interest for many industrial applications. This study applies the polyelectrolyte Nonrandom Two-liquid activity coefficient model to aqueous polyelectrolyte solutions with mixed-valent counterions. A modified Delocalized Binding Theory was proposed to determine the polyion condensation fractions of the mixed counterions. This modified theory accounts for the electrostatic binding of the counterions on the polyion, the dissociation entropy of the counterions, and the electrostatic interactions between the uncondensed ionic species. Given the polyion condensation fractions, the critical value of Manning’s parameter ξ and the amounts of uncondensed polyions and counterions can be calculated along with the activity coefficients of mobile ions. The model successfully correlates experimental data for various aqueous polyelectrolyte systems with mixed-valent counterions.

Phase equilibrium for the binary mixture of 1,1,2,3,3,3-hexafluoro-1-propene (R1216) + propane (R290) at temperatures from 283.15 to 313.15 K

Based on the study of the mixture containing 1,1,2,3,3,3-hexafluoro-1-propene (R1216) and propane (R290) by a set of static-analytical type experimental apparatus, this paper presents a series of vapour-liquid equilibrium data at the temperature from 283.15 K to 313.15 K. It is the first time to report the VLE data at a temperature below 313.15 K. Moreover, the uncertainties of pressure, temperature, and mole fraction in this experiment were determinate. The PR equation of state (EoS) combined with the following two models respectively, the van der Waals (vdWs) mixing rule and the Huron-Vidal (HV) mixing rule relating to the non-random two-liquid (NRTL) activity coefficient model were used to correlate the experimental VLE data of the binary system. Two models all presented an extremely content correlation of the experimental data for the R290 + R1216 mixtures, and the second model is more suitable as the pressure's maximum average relative and absolute deviation are 0.003 and 0.0026, respectively, and the maximum average absolute deviation of the vapor phase mole fraction AAD(y) is 0.0045. Near azeotropic phenomenon occurred within the temperature range of the experiment when the proportion of R290 is about 0.6 to 0.7.

Solid-liquid equilibrium of 3,3-dilauryl thiodipropionate/lauryl alcohol in melt crystallization and model based process design

Melt crystallization is a promising and widely used method for obtaining pure compounds. Nonetheless, separation of 3,3-dilauryl thiodipropionate (DLTP) has not yet been realized by melt crystallization. Solid-liquid equilibrium is the fundamental for the separation process design. In this work, we evaluated the feasibility of the purification of DLTP from the DLTP/lauryl alcohol (LA) binary mixture by melt crystallization technique. For this purpose, the solid-liquid equilibrium data were measured using differential scanning calorimetry (DSC) technique. The experimental data were correlated by Wilson, Margules-3-suffix and Non-Random Two-Liquid (NRTL) activity coefficient models to obtain the binary parameters of the three models. Eutectic composition and temperature were calculated using NRTL model, which were xLA = 0.961 (molar fraction) and 295.79 K, respectively. On the basis of the solid–liquid equilibrium, the multistage countercurrent separation configurations were proposed for the separation of the binary system. The formulated Mixed Integer Nonlinear Programming (MINLP) problem was solved using the branch-and-bound algorithm. The conceptual designs for multistage countercurrent configuration were derived based on MINLP optimization by comparing results at various conditions. Results showed that at least 3 crystallization stages with keff ≤ 0.4 are required to obtain the 99% (mass fraction) DLTP product within the initial concentration range from10% to 30% (mass fraction).

Phase equilibrium measurements and correlation for {tetrafluoromethane (R14) + propane (R290)} system

In this work, a study on the (vapour + liquid) equilibrium (VLE) and (vapour + liquid + liquid) equilibrium (VLLE) for the tetrafluoromethane (R14) + propane (R290) system was carried out using an apparatus based recirculation method at temperatures ranging from (173.150–212.470) K. The uncertainties of the composition, temperature, and pressure were less than 0.005, 5 mK and 2% or 0.0008 MPa, respectively. All of the experimental data were correlated by the Peng–Robinson equation of state (PR EoS) with the Modified Huron–Vidal second-order (MHV2) mixing rule involving the non-random two-liquid (NRTL) activity coefficient model. The results show good agreement with the experimental data, and the maximum root mean square deviations for (R14 + R290) system are Rp =0.0239 MPa, Rx = 0.009, respectively.

Potential of phosphonium-based ionic liquids to purify 1-propanol from water by liquid–liquid extraction at mild conditions

In order to reduce the environmental of the separation of 1-propanol from water in a residual industry stream for its reuse, the capability as solvents of two different trihexyl(tetradecyl)phosphonium ionic liquids (ILs) – trihexyl(tetradecyl)phosphonium chloride ([TDTHP][Cl]) and trihexyl(tetradecyl)phosphonium bromide ([TDTHP][Br])-, was studied. The liquid–liquid equilibria data for both ternary systems, {water + 1-propanol + [TDTHP][Cl]} and {water + 1-propanol + [TDTHP][Br]} at different mild work temperatures, (283.2, 303.2 and 323.2) K, and atmospheric pressure were measured. The thermodynamic parameters for both ternary systems at different work conditions were obtained by the non-random two-liquid activity coefficient model (NRTL) in order to achieve a posterior correct equipment design. Finally, the selectivity and distribution coefficient of [TDTHP][Cl] and [TDTHP][Br] were bibliographically benchmarked with different ILs, trihexyl(tetradecyl)phosphonium bis(2,4,4-trimethylpentyl)phosphinate ([TDTHP][Phosph]) and 1-decyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([dmim][Tf2N]), achieving a solubility of 1-propanol in the IL around 20 times greater than in water and a capability of [TDTHP][Br] to incorporate 1-propanol in its phase instead of in water rich phase around 40, which means, a great selectivity and values of the distribution coefficient close to the double in respect to the ILs researched. It could be concluded that both ILs, [TDTHP][Cl] and [TDTHP][Br], are capable to purify 1-propanol from water with great technical, environmental and economic advantages, in respect of the classical solvents and other ILs researched.

Binary mixture isothermal vapour-liquid equilibrium: Trifluoromethane (R23) + octafluoropropane (R218) at the temperature from 223.150 K to 263.150 K

The mixed-refrigerant Joule-Thomson refrigerator (MJTR) is simple in structure, safe and reliable, and is suitable for temperatures from 80 to 230 K. Trifluoromethane (R23) and octafluoropropane (R218) are satisfactory as non-flammable refrigerants in MJTR. In this paper, the gas-phase single-cycle method was used to conduct a vapor–liquid equilibrium (VLE) experiment on the R23 + R218 binary system in the temperature range from 223.150 K to 263.150 K. The VLE experimental data were correlated using the Peng-Robinson (PR) equation of state and the Huron-Vidal (HV) mixing rule combined with non-random two-liquid (NRTL) activity coefficient model. The maximum average absolute relative deviation of pressure (AARDp) and the maximum average absolute deviation of vapor phase composition (AADy) are 0.67% and 0.005, respectively.