Nonrandom Two-liquid Research Articles

Ternary Liquid-Phase Equilibria of an Azeotropic Mixture (Heptane + Isopropyl Alcohol) with Deep Eutectic Solvents

The present study reports the result of the measurement and analysis of the solubility curve and tie-line data of four ternary systems containing heptane–isopropyl alcohol azeotrope mixtures and deep eutectic solvents (DESs) at T = 298.2 K and p = 0.1 MPa. This investigation is aimed to evaluate the efficiency of the prepared DESs as extractants in the separation of the heptane–alcohol azeotropic mixtures through liquid–liquid extraction (LLE) processes. In this study, four choline chloride-based DESs were prepared by a heating process. Two hydrogen bond donor (HBD) compounds (i.e., ethylene glycol and propylene glycol) were chosen in the preparation of the DESs. The solubility curves show that the effect of DESs on the immiscibility region is small. The studied systems display the type-1 LLE behavior. The measured tie-line values were adequately fitted through the nonrandom two-liquid (NRTL) thermodynamic model, and the interaction parameter values were determined. The correlation data appeared to be in good agreement with the measured tie-lie data. The extraction capacity (distribution constants and selectivities) of the studied DESs was determined. The DESs had high and similar selectivity values for the studied systems. Moreover, the distribution constants were larger than unity, indicating a favorable solvent-to-feed ratio.

Thermodynamic solubility modeling of 2, 2ʹ, 4, 4ʹ, 6, 6ʹ - hexanitrostilbene (HNS)

Accurate thermodynamic modeling is essential for chemical process research and development. In this work, four thermodynamic models: UNIFAC, COSMO-SAC, Hansen Solubility Parameter (HSP) and Nonrandom Two-liquids Segment Activity Coefficient (NRTL-SAC) are examined for their utility to estimate the solubility of 2, 2ʹ, 4, 4ʹ, 6, 6ʹ - hexanitrostilbene (HNS) [CAS# 20062-22-0] in pure and mixed solvents. UNIFAC yields qualitatively correct HNS solubility predictions for a few solvents while COSMO-SAC fails to provide reliable predictions. In comparison to the two group contribution-based predictive models, the hybrid correlative and predictive model HSP gives qualitatively correct results for pure solvents while the other hybrid model NRTL-SAC provides qualitative to semi-quantitative predictions for HNS solubility in both pure and mixed solvents. NRTL-SAC is then used to predict the solubilities of HNS and 2, 2ʹ, 4, 4ʹ, 6, 6ʹ - hexanitrobibenzyl (HNBB) [CAS# 5180-53-0], an important byproduct of HNS synthesis, in Shipp reaction media for HNS synthesis. Moreover, n-octanol-water partition coefficients of HNS and HNBB are predicted with NRTL-SAC.

Simulation separation of triglycerides from Calophyllum inophyllum oil with continuous countercurrent extraction process using Aspen HYSYS

The trends of industry 4.0 transform a process design to a cost-effective development with digital simulation. The objective of this study was to simulate the separation and purification of triglycerides from crude Calophyllum inophyllum oil with a continuous countercurrent extraction method using Aspen HYSYS V.11 to find the appropriate binary parameter coefficients and predict the optimal conditions. It is expected that the oil’s purity suitable with the edible oil standards (minimum 96% triglycerides and 0.3% free fatty acids). The variables used are the flow rate (n-hexane + oil) to methanol and the total mass ratio of solvent to oil. The C. inophyllum oil used contains 63.91% triglycerides, 15.76% free fatty acids, 12.25% diglycerides, and 4.66% monoglycerides. It was evaluated by applying NRTL (Non-Random Two Liquid) and UNIQUAC (Universal Quasi Chemical) fluid packages with binary interaction parameters of UNIFAC-VLE, UNIFAC-LLE, Immiscible, and Modified (fitting parameters). The most suitable fluid package and binary interaction parameter pairing was achieved by combining NRTL fluid package with Modified binary interaction. The highest purity of triglycerides was 92.86%alongside a simulation error of 0.01% while the free fatty acid was 2.17% and 0.91%, respectively, at solvents (hexane and methanol) to oil mass ratio of 6:1 with a hexane-oil to methanol flow rate ratio of 6:15 (LPH/LPH). By upscaling the n number in the extractor, this model can predict the best result of separation and purification of triglycerides with the highest purity of triglycerides and free fatty acids were 96.736% and 0,0001%, respectively. Thus, the edible oil standards can be met.

Isothermal Vapor–Liquid Equilibrium for the Tetrafluoromethane (R14) + Octafluoropropane (R218) Binary Mixture at Five Temperatures from 173.150 to 213.150 K

Tetrafluoromethane (R14) and octafluoropropane (R218) are essential nonflammable refrigerants for mixed-refrigerant Joule Thomson refrigerators. In this paper, the vapor–liquid equilibrium (VLE) data were acquired for the R14 + R218 binary mixture from 173.150 to 213.150 K by a vapor-phase single-cycle method. The VLE data were regressed by the Soave–Redlich–Kwong (SRK) equation of state plus van der Waals (vdW) mixing rule model (SRK-vdW) and the Soave–Redlich–Kwong (SRK) equation of state combined with modified Huron–Vidal first-order (MHV1) mixing rule plus non-random two liquids (NRTL) activity coefficient model (SRK-MHV1-NRTL). The maximum average absolute relative deviation of pressure (AARDp) and the maximum average absolute deviation of vapor-phase mole concentration (AADy) are 2.42% and 0.0019 for the SRK-vdW model, respectively. A better correlation result was obtained by the SRK-MHV1-NRTL model, and the maximum AARDp and AADy are 1.04% and 0.0019, respectively. Based on the experimental and calculated results, a strong non-azeotropic behavior was found.

Measurement and Correlation of the Liquid-Liquid Equilibria of Tertiary-Butyl Alcohol – Water – Benzene System at 30°C and 1 Atmosphere Pressure

The Liquid-Liquid equilibria of Tertiary-Butyl Alcohol – Water – Benzene System were measured experimentally at 30°C and 1atm pressure. The experimental binodal curve compositions were obtained using the cloud point method. The compositions of the two equilibrium phases were analysed using Agilent 7820A series Gas Chromatograph. The consistency of the experimental data was determined using the Hand, Othmer-Tobias and Bachman- Brown correlation equations while the plate point was determined using the Treybal’s method. The effectiveness of the solvent in the extraction was determined by calculating the distribution coefficients and separation factors. The experimental tie-line data were correlated with the Universal Quasi-Chemical (UNIQUAC) and Non-Random Two Liquid (NRTL) activity coefficient models. Also, the deviation between the experimental and calculated equilibrium compositions were calculated using the root mean squared deviation equation. The UNIQUAC predicted data gave a closer resemblance to the experimental.

Solubility of carbon dioxide in promising methylimidazolium-based ionic liquids

One of the most pressing environmental concerns facing humanity today is the limitation of carbon dioxide emissions. In the field of natural gas sweetening, carbon capture is equally critical. CO2 solubility in three promising ionic liquids {1-Hexyl-3-methylimidazolium bis(trifluoro-methyl-sulfonyl) imide [HMIM][Tf2N], 1-Butyl-3-methylimidazolium dimethyl-phosphate [BMIM][DMP], and 1-Propyl-3-methylimidazolium (trifluoromethylsulfonyl)imide [PMIM][Tf2N]} was measured at (303.15, 323.15 and 343.15) K and pressures up to 1.4 MPa. The densities of the three ionic liquids were determined at atmospheric pressure (98.5 ± 0.8 kPa) and temperatures ranging from (293.15 to 343.15) K.The lowest Henry's Law constant (highest capacity) for CO2 was that of [HMIM][Tf2N] followed by [PMIM][Tf2N] and [BMIM][DMP]. [HMIM][Tf2N] also had a higher absorption capacity than Selexol/Genesorb 1753 and was second best only to 1-Octyl-3-methylimidazolium bis (trifluoro-methane sulfonyl) imide [OMIM][Tf2N] among all ionic liquids, based on solubility data published in the literature. Note that [BMIM][DMP] was also found to be among the best four ionic liquids according to the Henry's Law data collected from the literature.Three distinct mixing rules were used to correlate the experimental CO2 solubility data with the Peng-Robinson equation of state (PR-EoS) using the van der Waals one (vdW1), van der Waals two (vdW2), and the Wong-Sandler mixing rule along with the Non-Random Two-Liquid model (WS-NRTL). The average absolute deviations for vdW1, vdW2, and WS-NRTL mixing rules, when calculated for the three ionic liquid systems at the three temperatures, were 4.89 %, 0.82 %, and 0.84 %, respectively.

Vapor–Liquid Equilibrium for the Binary System of 2-Phenylethanol + 2-Ethylphenol at 50.0, 20.0, and 10.5 kPa

The vapor–liquid equilibrium (VLE) data for binary systems 2-PE and 2-EP were measured at 50.0, 20.0, and 10.5 kPa using a modified Rose equilibrium still. The Redlich–Kister area test and Fredenslund point test were applied to test the thermodynamic consistency of the VLE data, respectively. In addition, experimental data were successfully matched using nonrandom two-liquid (NRTL), Wilson, and Universal Quasi-Chemical (UNIQUAC) activity coefficient models. Binary interaction parameters (BIPs) corresponding to three models were obtained by maximum likelihood target function regression. This paper would help the distillation design of 2-phenylethanol and 2-ethylphenol in industrial applications.

Effect of electrolyte solubility and column inclination on the performance of monoethylene glycol regeneration process

AbstractIn this study, the solubilities of potassium‐chloride (KCl) in aqueous monoethylene glycol (MEG) solution and the vapour pressure of aqueous MEG solution containing KCl were investigated. A thermodynamic model was modified based on the data obtained to predict the solubilities of KCl, which was then applied to optimize the MEG regeneration process that is widely used in offshore gas fields. The solubility of KCl in the aqueous MEG solution decreased with an increase in MEG concentration and a decrease in temperature. The presence of KCl in aqueous MEG solution decreased the vapour pressure, thus increasing the boiling temperature at the corresponding pressure. A thermodynamic model based on the electrolyte non‐random two‐liquid (NRTL) coupled with the Redlich–Kwong (RK) equation of state was employed by modifying the binary interaction parameters using the experimental data. The modified model predicted the solubilities of KCl and the vapour pressure of aqueous MEG solutions, which were in good agreement with the experimental data. Moreover, the distillation column in pilot‐scale MEG regeneration was inclined to simulate the movement of the offshore platform, showing decreasing MEG concentration, possibly due to the distribution issues inside the column.

Liquid-liquid extraction of phenolic compounds from aqueous solution using hydrophobic deep eutectic solvents

This work evaluates the efficiency of extracting phenolic compounds (phenol, guaiacol, eugenol and pyrocatechol) from aqueous solution using Hydrophobic Deep Eutectic Solvents (HDESs). Four solvents were selected by screening HDESs database using the predictive model COSMO-RS (Conductor like Screening Model for Real Solvent): menthol: dodecanoic acid [2:1], decanoic acid: dodecanoic acid [2:1], octanoic acid: menthol [2:1] and thymol: menthol [1:1]. Experimental liquid–liquid equilibria of ternary systems {water – HDESs – phenolic compounds} measured at 298.15 K under atmospheric pressure were used to determine the distribution coefficient and selectivity values. Experimental data were used to determine the interaction parameters of the thermodynamic Non-Random Two-Liquid model (NRTL). NRTL model represents with good accuracy experimental data. COSMO-RS model predicts well the ternary systems containing phenolic compounds except those containing pyrocatechol. Finally, extraction of the four phenolic compounds from synthetic oil and kinetics study were performed. The extraction process using HDES: octanoic acid: menthol [2:1] exhibits the highest efficiency and more than 85 % of phenolic compounds are extracted after 5 min.

CO2 and H2S absorption in aqueous MDEA with ethylene glycol: Electrolyte NRTL, rate-based process model and pilot plant experimental validation

Acid gas absorption with aqueous amines is an important industrial technology for natural or flue gas treatment. To lower the high energy required for the regeneration process it has previously been proposed to replace a significant part of the water by a physical co-solvent with a lower specific heat. To investigate this idea, as well as the overall impact of adding a physical co-solvent, a detailed process model for CO2 and H2S absorption using an aqueous mixture of N-methyl diethanolamine (MDEA) – ethylene glycol (EG) is developed based on lab-scale experimental measurements of physical, thermodynamic, and kinetic properties. Those experiments indicate that the addition of EG reduces the solubility of the acid gases and that, despite the higher viscosity of the solvent, the impact on the rate of acid gas absorption is minor. Pilot plant tests further confirmed this. The vapor-liquid equilibrium (VLE) experiments were used to regress the thermodynamic electrolyte e-NRTL (Non-Random Two-Liquid) model parameters. In parallel, the kinetic measurements allowed to develop a rate-based model. All models were implemented in a commercial process simulator that was validated with high-pressure absorption–regeneration pilot tests with the solvent composition of 34 wt% MDEA, 44.5 wt% EG and 21.5 wt% H2O and with the raw gas composition of 2.5 mol% H2S and 2.5 mol% CO2. Comparison with aqueous MDEA (50 wt% MDEA, and 50 wt% H2O) shows that a reduction of 25 % in reboiler duty can be obtained when adding EG. Nevertheless, an 80 % increase in solvent flow rate is needed to get a similar acid gas absorption performance, and a higher co-absorption of hydrocarbons is observed.

Separation of Azeotropic Hydrofluorocarbon Refrigerant Mixtures: Thermodynamic and Kinetic Modeling for Binary Adsorption of HFC-32 and HFC-125 on Zeolite 5A.

Hydrofluorocarbons (HFCs) have been used extensively as refrigerants over the past four decades; however, HFCs are currently being phased out due to large global warming potentials. As the next generation of hydrofluoroolefin refrigerants are phased in, action must be taken to responsibly and sustainably deal with the HFCs currently in circulation. Ideally, unused HFCs can be reclaimed and recycled; however, many HFCs in circulation are azeotropic or near-azeotropic mixtures and must be separated before recycling. Previously, pure gas isotherm data were presented for both HFC-125 (pentafluoroethane) and HFC-32 (difluoromethane) with zeolite 5A, and it was concluded that this zeolite could separate refrigerant R-410A (50/50 wt % HFC-125/HFC-32). To further investigate the separation capabilities of zeolite 5A, binary adsorption was measured for the same system using the Integral Mass Balance method. Zeolite 5A showed a selectivity of 9.6-10.9 for HFC-32 over the composition range of 25-75 mol % HFC-125. Adsorbed phase activity coefficients were calculated from binary adsorption data. The Spreading Pressure Dependent, modified nonrandom two-liquid, and modified Wilson activity coefficient models were fit to experimental data, and the resulting activity coefficient models were used in Real Adsorbed Solution Theory (RAST). RAST binary adsorption model predictions were compared with Ideal Adsorbed Solution Theory (IAST) predictions made using the Dual-Site Langmuir, Tóth, and Jensen and Seaton pure gas isotherm models. Both IAST and RAST yielded qualitatively accurate predictions; however, quantitative accuracy was greatly improved using RAST models. Diffusion behavior of HFC-125 and HFC-32 was also investigated by fitting the isothermal Fickian diffusion model to kinetic data. Molecular-level phenomena were investigated to understand both thermodynamic and kinetic behaviors.

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.

Thermophysical characterization of terpenoid based hydrophobic deep eutectic solvent and its Vapour-Liquid equilibrium studies with furfural

The sustainable transition to cleaner production techniques over the last decade has projected deep eutectic solvents as alternative solvents to replace toxic volatile organic solvents especially in green extraction technologies. However, processes based on such newly developed solvents pose hindrances in industrial applicability due to lack of sufficient data for process design and scale up. Prospectively, a new hydrophobic deep eutectic solvent (HDES) that has been utilized for the selective extraction of biomass derived furfural from its aqueous solutions composed of thymol and 1-tetradecanol in 2:1 M ratio has been subjected to exhaustive thermo-physical characterization and phase equilibrium measurements in the present study. The various physico-chemical properties of the HDES such as density, viscosity, ionic conductivity as well as refractive index and acidity were measured as a function of temperature from 293.15 K to 333.15 K and suitably correlated. The thermal limit of operation for the HDES was analyzed through thermo-gravimetric analysis while its structural characterization was conducted by Fourier transform infrared spectroscopy. A modified Othmer type ebulliometer was used for the vapour pressure measurements of the HDES from 2.4 to 10.4 kPa and the experimental data was fit to the Antoine and Clark-Glew equations. Further, the isobaric vapour liquid equilibrium data at different sub-atmospheric pressures for the HDES and furfural system was generated and data regression using the non-random two liquid (NRTL) model was used to derive the optimized binary interaction parameters.

Solubility determination and mixing thermodynamic properties of R1243zf in two 1-butyl-3-methyl-imidazolium based ionic liquids

3,3,3-Trifluoropropene (R1243zf), as a new-type hydrofluoro-olefin refrigerant with extremely low GWP and thermophysical properties similar to R134a, has received more and more attention. Ionic liquids (ILs) with 1-butyl-3-methyl-imidazolium ([BMIM]+) cation are a promising kind of absorbent in absorption refrigeration cycle (ARC) owing to their low viscosity level and good stability. Towards better understanding the phase behavior of R1243zf/[BMIM]+ IL mixtures and promoting their application in ARC, the solubilities of R1243zf in [BMIM][TFO] and [BMIM][PF6] were experimentally determined using isochoric saturation method in this work. The non-random two liquid (NRTL) and Krichevsky-Kasarnovsky (K-K) model were utilized to correlate the experimental data, and both models exhibited reasonable results. In addition, the dissolution thermodynamic properties (enthalpy, entropy and Gibbs energy) and Henry’s law constants of R1243zf in the two ILs were calculated, and the variation with solubility was analyzed. Furthermore, the absorption capacities of [BMIM][TFO] and [BMIM][PF6] to different refrigerants were compared based on the reported data in the literatures.

Thermodynamic analysis of H2O − 3-aminopropyl tributyl phosphonium glycinate as a working pair for absorption refrigeration system

In this paper, A hydrophilic dual amino-functionalized ionic liquid 3-aminopropyl tributyl phosphonium glycinate ([aP4443][Gly]) with high thermal stability was used as absorbent and the refrigerant was water for the absorption refrigeration system (ARS). The heat capacities of the system were estimated by the differential scanning calorimetry (DSC) with various water mass fractions (w1) (0.004 to 0.6993) and temperatures (285 K to 365 K), and a polynomial equation on temperature and mass fraction of ionic liquid (w2) was associated. Between the experimental and estimated values, the average relative deviation (ARD) was 0.66%. The vapor–liquid equilibrium (VLE) data of the H2O–[aP4443][Gly] binary mixture was correlated using the electrolyte nonrandom two-liquid (eNRTL) model, and the binary mixture's excess thermodynamic properties were simulated. The first and second laws of thermodynamics were used to simulate the performance of a single-effect ARS with a solution heat exchanger (SHE). The ARS simulation results show that the coefficient of performance (COP) of the system with H2O–[aP4443][Gly] as the working pair is higher than that of the conventional working pair NH3-H2O but slightly lower than that of H2O-LiBr. Furthermore, the effect of generator temperature (Tg) on ARS is investigated; simulation results show that the ARS of the novel working pair has a higher COP value at higher generator temperature, indicating that H2O–[aP4443][Gly] has the potential to be a new type of absorption refrigeration working pair.

Modeling of CH4/CO2 hydrate phase behavior in organic and electrolyte inhibitors by dickens’ model

The main purpose of this study is investigating a reliable and convenient model based on Dickens and Quinby-Hunt approach to predict CH4/CO2 gas hydrate equilibrium temperature in presence of organic inhibitors (e.g., methanol, ethanol, ethylene glycol, triethylene glycol, glycerol), and electrolyte inhibitors (e.g., NaCl, KCl, NaBr, KBr, CaCl2, CaBr2, MgCl2, EMIM-Cl, BMIM-Cl, BMIM-Br, BMIM-I, BMIM-DCA, EMIM-HSO4, EMIM-EtSO4, and EMIM-MeSO4). This model named as Dickens’ model is an activity-based model and to calculate water activity of organic solutions the nonrandom two-liquid (NRTL) and Margules was used. Also, Pitzer model was employed to calculate activity of water in electrolyte solutions. A correlation was suggested to determine enthalpy of hydrate dissociation in terms of inhibitor weight percent and equilibrium pressure. Due to no data in open literature, the virial coefficients of Pitzer model in ionic liquid solutions were adjusted. The model results were compared with available experimental data from open literature and observed to be in good agreement with the reported literature.

Vapor-liquid equilibrium measurements of 3, 3, 3‑trifluoropropene with pentaerythritol tetraheptanoate and pentaerythritol tetranonanoate

Vapor-liquid equilibrium measurements for 3, 3, 3‑trifluoropropene (R1243zf) with pentaerythritol tetraheptanoate (PEC7) and pentaerythritol tetranonanoate (PEC9) were performed using isochoric saturation method over temperatures from 278.15 K to 343.15 K and pressures up to 1.0 MPa. The experimental data were regressed by non-random two liquid (NRTL) activity coefficients model. In addition, the dissolving abilities of different refrigerants (R1243zf, R600a, RE170, R1234ze(E), R152a, R134a, R1234yf) in PEC7 and PEC9 were compared and analyzed.

Effect of cosolvent on the solubility of glucose in ionic liquids: Experimental and molecular dynamics simulations

The present study attempts to measure the solubility of glucose in three neat ionic liquids (ILs), namely 1-ethyl-3-methylimidazolium methylsulfonate [Emim][MeSO3], 1-ethyl-3-methylimidazolium ethyl sulfate [Emim][EtSO4], 1-ethyl-3-methylimidazolium thiocyanate [Emim][SCN] and IL/cosolvent mixtures as a function of temperature. The IL [Emim][MeSO3] has shown higher solubility of glucose than other ILs. The experimental glucose solubility data was further correlated with Apelblat empirical equation along with regression using a local thermodynamic model such as NRTL (non-random two-liquid). The thermodynamic functions of dissolution, such as enthalpyΔdissol∘H, Gibbs energy Δdissol∘G and entropy Δdissol∘S were also determined using the modified van't Hoff equation. The dissolution functions for all the systems studied were positive, indicating that the process is endothermic, non-spontaneous, and entropically viable. Dimethyl sulfoxide (DMSO) was added as a cosolvent to enhance the solubility of glucose in ILs by reducing viscosity, which leads to a higher mass transfer rate of solute in solvent even at low temperatures. Furthermore, we performed molecular dynamics (MD) simulations to understand the microscopic interactions of glucose-IL and glucose-IL/DMSO systems. From the MD simulations, it was observed that anions of IL dominate the solvation of glucose, whereas the cation plays a secondary role. The addition of DMSO to ILs, weakens the stronger interactions between anion and cation of IL, thereby enhancing the solvation of glucose by increasing the interaction energies and contact probabilities between glucose and anion of ILs.

Solubility measurement, correlation and mixing properties of thioacetamide in fifteen pure solvents

The solubility of thioacetamide in fifteen pure solvents (methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, n-pentanol, isopentanol, ethyl acetate, 2-butanone, 2-pentanone, acetone, acetonitrile, ethyl formate and methyl acetate) was determined by a gravimetric method from 272.85 K to 323.95 K under ambient pressure. Four thermodynamic models, including the modified Apelblat equation, Buchowski-Ksiazaczak λh equation, non-random two-liquid (NRTL) model and the Wilson model were used to correlate the solubility data. And the NRTL model provides the best data fitting results among the four models. To elucidate the dissolution behavior of thioacetamide, the KAT-LSER model was introduced to analyze the solvent effect. The results revealed that hydrogen bond basicity and bipolarity/polarizability had a similar and significant favorable effect to the dissolution of thioacetamide. The mixing thermodynamic properties such as enthalpy, entropy and Gibbs free energy were calculated and the results indicated that the dissolution process of thioacetamide was spontaneous and favorable.

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.