Liquid Phase Equilibrium Data Research Articles

A study on the vapor–liquid equilibria of vinyl acrylate-acetic acid and vinyl acetate-acetic acid with GEMC method

Vinyl acetate (VAc) is one of the widely utilized industrial organic raw materials. In the acetoxylation of ethylene to vinyl acetate, there is a by-product vinyl acrylate. However, the vapor–liquid phase equilibrium data of this component with acetic acid and vinyl acetate have not been reported. Here, by Density Functional Theory calculations, we fitted the TraPPE-UA force field parameters of vinyl acrylate. The vapor–liquid phase equilibrium data of the vinyl acrylate-acetate and vinyl acrylate-vinyl acetate binary systems were calculated using the Gibbs Ensemble Monte Carlo (GEMC) method. The calculated phase equilibrium data were utilized to fit the binary interaction parameters of the NRTL equations for the binary systems which were used for the separation process simulation of the vinyl acrylate, acetic acid and vinyl acetate systems. It was verified that the TraPPE-UA force field parameters fitted in this paper have high accuracy. The results clarify the concentration distribution of vinyl acrylate gas–liquid phase components in the distillation column, which builds the foundation for the development of the separation process.

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.

Analysis of solid-liquid equilibrium behavior of highly water-soluble beet herbicide metamitron in thirteen pure solvents using experiments and molecular simulations

Metamitron (MET), a highly water-soluble herbicide for sugar beets, has posed a significant threat to aquatic species due to its high solubility in water; therefore, understanding its solid–liquid phase equilibrium data in different solvents is essential for the future development of more environmentally friendly forms. In this study, the solubility data of MET in 12 pure solvents were determined gravimetrically and analyzed using theoretical methods (primarily Molecular electrostatic potential surface analysis, Hirshfeld surface analysis, Reduced Density Gradient analysis, radial distribution function, and solute–solvent interaction energy) to further investigate the solid–liquid equilibrium behavior. Although MET's high solubility in water contributes to environmental contamination, its value is low in comparison to that of other organic solvents. Four models, including the Apelblat equation, the λh equation, the van't Hoff equation, and the NRTL, were used to examine all solid–liquid equilibrium data, and an ARD% below 5 confirmed its good correlation. The MET solubility data is anticipated to provide solid guidance for the future development of more effective and environmentally acceptable green formulations.

Isothermal vapor–liquid equilibrium of ternary system (difluoromethane + propane + trifluoroiodomethane) at temperatures ranging from 263.15 K to 303.15 K

In this paper, a static analytical apparatus has been developed to measure the vapor–liquid phase equilibrium property. The saturated vapor pressures of R32, R290, and R13I1 at temperatures from 253.15 to 303.15 K were measured. Satisfactory agreement with published calculation and experimental data are found and the reliability of the experimental setup is verified. The vapor–liquid phase equilibrium data for R32 + R290 + R13I1 ternary system were measured at 263.15, 283.15, and 303.15 K. The standard uncertainties were estimated to be 13 mK for temperature, 1300 Pa for pressure and 0.008 for mole fraction. The data were regressed by the PR-vdW model and the PR-NRTL-MHV2 model. The PR-NRTL-MHV2 model gives a better description of the experimental values with maximum average absolute relative deviations of 0.9% for pressure and maximum absolute deviation of 0.016 for vapor mole fraction. No azeotropic behaviour can be observed for the ternary system.

Extraction of allyl alcohol from its aqueous solution using two different ionic liquids: Intermolecular interaction and liquid-liquid phase equilibrium explorations

Allyl alcohol is a remarkable chemical intermediate. During its preparation by allyl acetate hydrolysis, an aqueous mixture is usually obtained. Because allyl alcohol can form a minimum boiling point azeotropic mixture with water, it is impossible to separate such a mixture by conventional distillation. In this work, for recovering allyl alcohol by extraction, the ionic liquid extractants (ILs) were adopted by the model of COSMO-SAC and two ILs 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([BMP][Tf2N]) and 1-octyl-3-methylimidazolium trifluoromethanesulfonate ([OMIM][OTf]) were selected. The length of the hydrogen bond and the energy of the interaction between the ILs and (allyl alcohol/water) were calculated by quantum chemical calculations. The experimental liquid–liquid phase equilibrium (LLE) data for the ternary systems (water + allyl alcohol + [OMIM][OTf]/[BMP][Tf2N]) were explored at 298.15 K. The [OMIM][OTf] and [BMP][Tf2N] extraction capability was assessed with selectivity and partition ratio. In addition, the NRTL model was used to fit the measured tie-line values.

Measurement and Correlation of Liquid–Liquid Equilibria of Water (1) + 1-Methylimidazole (2) + [Bmim][PF6] (3) Ternary Systems between 303.15 and 323.15 K

To obtain the basic data for the recovery of 1-methylimidazole from wastewater by extraction, the ternary liquid–liquid phase equilibrium data of the water (1) + 1-methylimidazole (2) + 1-butyl-3-m...

Measurement and modelling of ternary solid–liquid phase equilibrium of (DL-malic acid + maleic acid + water) from 283.15 K to 333.15 K

The solid–liquid phase equilibrium data of (DL-malic acid + maleic acid + water) in binary and ternary systems were measured by high performance liquid chromatography (HPLC) method at 283.15 K, 293.15 K, 303.15 K, 313.15 K, 323.15 K and 333.15 K under atmospheric pressure, and then six isothermal ternary phase diagrams were established. Each isothermal ternary phase diagram included one co-saturated point (invariant), two saturated boundary curves, and three crystallization regions (DL-malic acid, maleic acid, and mixture of both). For extending the application of measured solid–liquid phase equilibrium data, the Wilson model and NRTL model were used for correlation and prediction, and the relative average deviation (RAD) and root-mean-square deviation (RMSD) were applied to assess the calculation precision. The maximum values of RAD and RMSD were 2.61 × 10−2 and 1.87 × 10−3 with Wilson model, 3.31 × 10−2 and 1.86 × 10−3 with NRTL model, respectively, which demonstrated that the calculated data were close to the experimental data, and accurate theoretical data under other experimental conditions were able to acquire through the two models in DL-malic acid + maleic acid + water system. The study provided reliable and accurate data for separating the mixture of DL-malic acid and maleic acid in water.

New Vapor–Liquid Phase Equilibrium Data of CO2 in Several Heavy n-Alkanes at High Pressures

New phase equilibrium data of CO2 in n-hexadecane, n-heptadecane, n-octadecane, n-nonadecane, and n-eicosane were measured at temperatures from 333.15 to 373.15 K up to 23.73 MPa by a constant-volu...

Isobaric Vapor–Liquid Phase Equilibrium Measurements of the Dichloromethane–Titanium Tetrachloride System at 101,325 Pa

Isobaric vapor–liquid phase equilibrium (VLE) data of the titanium tetrachloride (1) + dichloromethane (2) system were measured by a modified Rose equilibrium still at 101,325 Pa. Raman spectroscopy was employed to quantitatively analyze the concentrations of titanium tetrachloride and dichloromethane in the samples from the still. The Herington method and the McDermott–Ellis method were used to check the thermodynamic consistency of the experimental data, which were correlated by the Wilson and NRTL models to obtain binary interaction parameters. The results show that the calculated values of mole fraction of the vapor phase and boiling temperature by the Wilson and NRTL models agree well with the experimental data. Finally, the T–x–y diagram was drawn according to the VLE data and calculated data from the Wilson and NRTL models. There is a negative deviation of the new binary system from ideal solution and no azeotropic behavior was found. All these results could guide the separation of dichloromethane and titanium tetrachloride.

Measurement and correlation of the vapor-liquid equilibrium of cyclohexane + ethanol containing ILs and the thermophysical properties of these ILs at 101.3 kPa

Some important topics and issues related to possible extractive distillation separation of cyclohexane + ethanol system using ionic liquids (ILs) are presented in this manuscript. Three ILs with acetate anion (methyl-trioctyl-ammonium acetate [N1,8,8,8][Ac], 1-decyl-3-methyl-imidazolium acetate [DMIM][Ac] and 1-hexadecyl-3-methyl-imidazolium acetate [C16MIM][Ac]) were selected as entrainers. The vapor–liquid phase equilibrium (VLE) data for cyclohexane + ethanol + ILs system were determined at 101.3 kPa and correlated by Wilson and NRTL models. The separation effect of these ILs on the basis of the NRTL model follows this order: [N1,8,8,8][Ac] > [DMIM][Ac] > [C16MIM][Ac]. The binary VLE data of the cyclohexane-ethanol mixture obtained by this device were compared with previously published data and tested by the Herington thermodynamic consistency test. Temperature dependence of some thermophysical properties (density, viscosity and heat capacity) of these ILs were obtained and correlated within the range of possible distillation operating temperatures.

Estimation and Correlation of Phase Equilibrium of CO2–Hydrocarbon Systems with PRMHV2-UNIFAC and PRMHV2-NRTL Models

In this work, the Peng–Robinson (PR) equation of state (EoS) and MHV2 mixing rule that were combined with UNIFAC and NRTL GE models were used to predict vapor–liquid phase equilibrium (VLE) data for CO2–hydrocarbon systems. These systems included 12 binary systems and three ternary systems. The PRMHV2-UNIFAC model was used to calculate the bubble pressure, and the average absolute relative deviations (AARD %) were 17.49–32.20% for 12 binary systems. For the PRMHV2-NRTL model, the binary interaction parameters of the NRTL model dependent on temperature were regressed based on the binary VLE data. These new interaction parameters were used to estimate CO2–hydrocarbon VLE data for binary and ternary systems. The bubble pressure was predicted by the PRMHV2-NRTL model, and the AARD % values were 1.52–9.44% for binary systems, which were lower than the value of the PRMHV2-UNIFAC model. The PRMHV2-UNIFAC and PRMHV2-NRTL models were also used to calculate the liquid phase mole fraction of CO2–hydrocarbon ternary ...

Phase equilibrium measurement, thermodynamics modeling and process simulation for extraction of phenols from coal chemical wastewater with methyl propyl ketone

The extraction of phenols from coal chemical industry wastewater with methyl propyl ketone was studied in this work by experimental determination and process simulation. Phenol and hydroquinone were separately selected as the representatives of phenolic pollutants in the phenols-containing coal chemical industry wastewater. The liquid–liquid phase equilibrium data for methyl propyl ketone+phenol+hydroquinone+water quaternary system were measured at 40°C and 101.3kPa. The NRTL and UNIQUAC models were used to correlate the experimental data to achieve binary interaction parameters. The process simulation for the extraction of phenols from coal chemical industry wastewater with methyl propyl ketone was developed to obtain optimized operation parameters with the binary interaction parameters fitted from the experiment. The simulation results show that, the concentration of total phenols in the coal chemical industry wastewater could be reduced from 12,700mgL−1 to 313mgL−1 in the stream of the bottom in the stripping column, which is suitable for further biochemical treatment of the wastewater. The extraction solvent could be recycled through the distillation column and the stripping column. The crude phenols would be as by product in the phenols extraction and solvent recovery.

Calculation of the Phase Equilibrium of CO2–Hydrocarbon Binary Mixtures by PR-BM EOS and PR EOS

The phase equilibrium data of CO2–hydrocarbon binary mixtures are important for the design and operation of CO2 flooding, coal liquefaction, and supercritical extraction processes. Numerous pieces of binary phase equilibrium data have been obtained. Thus, models for the accurate calculation of binary and multicomponent mixtures must be developed on the basis of existing data. In this work, 3578 vapor–liquid phase equilibrium data points for 10 CO2–hydrocarbon binary mixtures, including CO2–butane, CO2–pentane, CO2–isopentane, CO2–hexane, CO2–benzene, CO2–heptane, CO2–octane, CO2–nonane, CO2–decane, and CO2–undecane, were collected. The PR and PR-BM equations of state (EOS) in combination with relevant mixing rules were used to calculate the phase equilibrium data of the CO2–hydrocarbon binary mixtures. The binary interaction parameter kij in the PR EOS was temperature independent, whereas parameters in the PR-BM EOS were functions of temperature. Thus, the phase equilibrium data and other thermodynamic properties of the binary and multicomponent mixtures at different temperatures and pressures can be calculated by using the parameters obtained in this work. The PR-BM EOS performed better than the PR EOS, and the average absolute deviations over the temperature range of 255.98–408.15 K calculated by the PR EOS and PR-BM EOS were less than 5.74% and 3.36%, respectively. The results calculated by the two EOS were compared with those calculated by other models, such as PPR78, PR + LCVM + UNIFAC, KIE + PR EOS + HV, and PSRK. The phase equilibrium data of CO2–butane–decane, CO2–hexane–decane, and CO2–octane–decane ternary mixtures were calculated by the two EOS. The average overall deviations for the CO2 mole fractions calculated by the two EOS were less than 7.66%.

Liquid–liquid extraction of sulfur compounds from heptane with tricyanomethanide based ionic liquids

Liquid–liquid phase equilibrium (LLE) data for the {tricyanomethanide-based ionic liquid (1) + tiophene, or benzothiophene (2) + heptane (3)} ternary systems were experimentally determined at T = 308.15 K and at pressure p = 0.1 MPa. In this work three ILs, that is: 1-butyl-1-methylmorpholinium tricyanomethanide, [BMMOR][TCM], 1-butyl-1-methylpyrrolidinium tricyanomethanide, [BMPYR][TCM] and 1-hexyl-1-methylmorpholinium tricyanomethanide, [HMMOR][TCM] have been investigated. The high solubility of sulfur compounds and practically complete immiscibility of heptane with the tested ionic liquids have been observed. The selectivity, S12 and solute distribution ratio, k12 derived from the experimental equilibrium data, were calculated and used to determine the efficiency of these ionic liquids as solvents for the extraction of sulfur compounds from model fuels. The experimental results have been compared to literature data for other tricyanomethanide-based ILs and were discussed in terms of the selectivity and solute distribution ratio of separation of related systems. The NRTL equation was successfully used to correlate the experimental tie-lines. The average root mean square (RMSD) of the phase composition was less than 0.8%. Additionally, the oxidative-extractive desulfurization of model fuels has been studied using tricyanomethanide-based ionic liquid (IL): [BMMOR][TCM] and [BMPYR][TCM] and deep eutectic solvent (DES): ([BMMOR] [Br] + diethylene glycol). Model liquid fuel was prepared by dissolving benzothiophene in octane, 500 ppm of sulfur. Oxidation was achieved by adding hydrogen peroxide and acetic acid to the mixture. Different parameters such as a type of extractant, extraction time, and oxidant to sulfur molar ratio and temperature were optimized. The addition of oxidizing agent improves the efficiency of sulfur extraction and the highest extraction efficiency, equal to 69.1%, was obtained for [BMMOR][TCM] at T = 318.15 K.

The influence of bromide-based ionic liquids on solubility of {LiBr (1) + water (2)} system. Experimental (solid + liquid) phase equilibrium data. Part 1

In this work, nine ILs are investigated as anti-crystallization additives to (LiBr+water) binary systems conventionally used as a working pair in absorption refrigeration technology. The solubility of {LiBr (1)+IL (2)+water (3)} ternary systems within wide temperature and composition range was determined by the dynamic method. In this work, the following ILs: 1-ethyl-1-methylmorpholinium bromide, [C1C2MOR][Br], 1-butyl-1-methyl-morpholinium bromide, [C1C4MOR][Br], 1-hexyl-1-methylmorpholinium bromide, [C1C6MOR][Br], 1-butyl-3-methylimidazolium bromide, [C1C4IM][Br], 1-ethyl-1-methyl-piperidinium bromide, [C1C2PIP][Br], 1-butyl-1-methylpiperidinium bromide, [C1C4PIP][Br], 1-butyl-1-methyl-pyrrolidinium bromide, [C1C4PYR][Br], 1-butylpyridinium bromide, [C4Py][Br] and tri(ethyl)-butylammonium bromide, [N2,2,2,4][Br] were investigated. The experimental (solid+liquid) phase equilibria have been determined for different IL to LiBr mass fractions from w2=(0.1 to 0.3). For all of the tested system, the transition point between lithium bromide dihydrate and monohydrate form was observed. Additionally, the simple model based on the multicomponent Redlich-Kister equation and a reference state of pure chemical compounds was used to successfully describe solubility of lithium bromide in aqueous systems containing an ionic liquid. The influence of ILs cation's core on the crystallization temperature of aqueous lithium bromide system was discussed and the best IL as an anti-crystallization additive has been proposed.

Solubility Measurement, Modeling, and Thermodynamic Functions for para-Methoxyphenylacetic Acid in Pure and Mixed Organic and Aqueous Systems

The solubility of para-methoxyphenylacetic acid in different solvents is of critical significance for the design and optimization of its purification process via crystallization. The present study illustrates new solid–liquid phase equilibrium data of para-methoxy phenyl acetic acid in water, acetonitrile, propan-2-ol, morpholine, toluene, anisole, and binary (propan-2-ol + water, propan-2-ol + toluene) mixed solvents using a static analytical method from 283.15 to 323.15 K at atmospheric pressure. The highest solubility of para-methoxyphenylacetic acid was observed in propan-2-ol and lowest in water, with the maximum solubility effect for propan-2-ol + toluene binary system obtained at 0.5001 solute-free mole fraction of propan-2-ol. The modified Apelblat equation, λh (Buchowski) equation, and nonrandom two-liquid (NRTL) activity coefficient model were used to correlate the experimental solubility data in pure solvents, whereas the binary solvent systems were modeled using the van’t Hoff–Jouyban–Acree, A...

Measurement and Correlation of Isobaric Vapor–Liquid Equilibrium for Binary Systems of Allyl Alcohol with Isobutyl Acetate, Butyl Acetate, and Butyl Propionate at 101.3 kPa

For separation of the azeotrope of allyl alcohol and water, three extractive agents—isobutyl acetate, butyl acetate, and butyl propionate—were selected to extract allyl alcohol from the azeotrope. To recover the extractive agents by distillation, the isobaric vapor–liquid phase equilibrium (VLE) data for allyl alcohol + isobutyl acetate, allyl alcohol + butyl acetate, and allyl alcohol + butyl propionate were measured at 101.3 kPa. With the VLE data, there is no azeotrope formed in three systems. The consistency of the measured VLE data was validated by the Herington, infinite dilution, pure component consistency, and van Ness tests. Moreover, the Wilson, UNIQUAC, and NRTL models were used to fit the measured VLE data. All of the calculated results agreed with the VLE experimental data. Meanwhile, the parameters of the Wilson, UNIQUAC, and NRTL were regressed, which can be employed for the development and optimization of the separation process. Furthermore, the VLE data were predicted by the UNIFAC model ...

The experimental investigation of the vapour liquid phase equilibrium for (ammonia + 2,3,3,3-tetrafluoroprop-1-ene) system

Searching for mixed alternative refrigerants with less influence on global warming is one of the main tasks of the refrigeration industry. This paper presents the vapour liquid phase equilibrium and vapour liquid liquid phase equilibrium data of (ammonia+3,3,3-tetrafluoroprop-1-ene) system at temperature from 243.150K to 283.150K. The vapour pressures of 3,3,3-tetrafluoroprop-1-ene were compared with Refprop 9.1, and the maximum deviation of pressure is 0.0007MPa. The VLE and VLLE data were regressed by the PR-MHV2-NRTL model. Good reproduction was shown with the maximum RT=0.009K, Rp=0.0040MPa, Rx=0.013 and Ry=0.013. The homogeneous or heterogeneous azeotropic behaviours were found for the systems concerned over the temperature ranges investigated. The present results suggest that the volumetric refrigeration capacity of (ammonia+2,3,3,3-tetrafluoroprop-1-ene) azeotropic mixture is 15% higher than that of ammonia and 79% higher than that of 2,3,3,3-tetrafluoroprop-1-ene.

Experimental measurement and thermodynamic modeling of binary and ternary solid–liquid phase equilibrium for the systems formed by l -arabinose, d -xylose and water

Solid–liquid phase equilibrium data for binary (l-arabinose–water) and (d-xylose–water) systems at temperatures from (269.85–298.05) K and ternary (l-arabinose–d-xylose–water) system at temperatures of 273.85 K, 278.85 K and 284.45 K were measured at atmospheric pressure. The ternary phase diagrams of the systems were constructed on the base of the measured solubility. Two pure solid phases were formed at given temperatures, including pure l-arabinose and pure d-xylose, which were confirmed and determined by the method of Schreinemakers' wet residue. At the same temperature, the crystallization region of l-arabinose was larger than d-xylose's. The acquired solubility data were then correlated using the NRTL model, Wilson model and Xu model. The calculated solubility with the three models agreed well with the experimental values.

Vapour–Liquid Equilibrium for N, N-Dimethylformamide + Benzene + Thiophene via Gibbs Ensemble Molecular Simulation

The selection and design of an optimal solvent for extractive distillation require reliable vapour–liquid phase equilibrium data and knowledge of extraction mechanisms. Compared with time-consuming experiments, molecular simulation presents great potential in research on the properties of fluids. Therefore, in this work, Gibbs ensemble Monte Carlo was applied to successfully predict the vapour–liquid phase equilibrium data of binary and ternary systems containing benzene, thiophene and N, N-dimethylformamide (DMF) at P = 101.3 kPa. The explicit hydrogen version of the transferable potentials for phase equilibria potential model was chosen for benzene and thiophene, whereas the OPLS potential model was selected for DMF. The predicted phase diagrams were compared with experimental data and the UNIQUAC thermodynamic model. A good agreement was obtained, which corroborated the validity of the potential models. In addition, the extraction mechanism was explored by radial distribution function (RDF) of the liquid-phase structure. The RDFs showed that thiophene and benzene shared a similar liquid-phase structure because of the intermolecular interaction. The distinct difference between the RDFs of DMF/benzene and those of DMF/thiophene is that the oxygen atom of DMF is more associated with hydrogen atoms of thiophene than that of benzene, which may be responsible for the extraction effect of DMF.