Isobaric Vapor-liquid Equilibrium Data Research Articles

Isobaric vapor–liquid equilibrium for water + acetic acid + 1-butyl-3- methylimidazolium dibutylphosphate at 101.32 kPa

The removal and recycling of acetic acid from acetic acid+water mixture has a great significance for environmental protection and resource utilization. After the addition of ionic liquid (IL) 1-butyl-3-methylimidazolium dibutylphosphate [BMIM][DBP], the boiling point difference of the water+acetic acid system increased from 17.88K (0 mass % IL) to 41.13K (about 59 mass % IL), and the relative volatility (x1′=0.9) increased from 1.60 (0 mass % IL) to 9.81 (about 57 mass % IL). [BMIM][DBP] showed a remarkable entrainer performance for the separation of acetic acid from aqueous solution. In this work, Isobaric vapor-liquid equilibrium (VLE) data of the systems water+acetic acid, water+[BMIM][DBP], acetic acid+[BMIM][DBP], and water+acetic acid+ [BMIM][DBP] were determined at 101.32kPa by using an improved Rose–Williams equilibrium still. Based on the chemical theory and Hayden–O’Connell (HOC) method, the parameters of NRTL model for the binary systems were obtained, and the predicted values of the ternary systems of water+acetic acid+[BMIM][DBP] fitted the experimental VLE data well.

Phase equilibria and interfacial tensions in the systems ethanol + 2-methoxy-2-methylbutane + hexane

Isobaric vapor–liquid equilibrium data have been measured for the ternary system ethanol+2-methoxy-2-methylbutane+hexane at 94kPa and in the temperature range 331–350K. Equilibrium determinations were performed in a vapor–liquid equilibrium still with circulation of both phases. The dependence of interfacial tensions of the ternary mixture on concentration was also experimentally determined at atmospheric pressure and 303.15K, using the maximum differential bubble pressure technique.From the experimental results, it follows that the ternary mixture exhibits positive deviation from ideal behavior. The application of a model-free data treatment approach allows concluding about the reliability of the present vapor–liquid equilibrium data. Furthermore, the determined interfacial tensions exhibit both positive and negative deviations from linear the behavior, and double aneotropy is observed.The vapor–liquid equilibrium data of the ternary mixture were well-predicted by the NRTL, Wilson and UNIQUAC activity coefficient models using binary parameters only. The interfacial tensions were smoothed using the Myers–Scott expansion, showing a significant contribution of parameters that describe three-body interactions, thus suggesting that the ternary IFT data cannot be directly predicted from the binary contributions.

Isobaric Vapor Liquid Equilibrium at 101.3 kPa for the Binary Mixtures 2-Methyl-2-Butene / TAME and 2-Methyl-1- Butene / TAME

Due to the increased interest for using tertiary ethers as fuel additives (such as TAME – tert-amyl-methylether synthesis), the research intensified to study its thermodynamic aspects. Mathematical modelling of tertiary ethers synthesis includes a number of elements characterizing the process thermodynamics. The liquid – vapour equilibrium data is used to get an insight about the deviations from ideal behaviour of the components in the two phases. This kind of information needed to characterize the process thermodynamics are widely available from literature, but sometimes with doubts related to accuracy, which leads to the necessity of experimental checking. TAME is formed by reaction of isoamylenes present in FCC C 5-fraction (2-methyl-1-butene and 2-methyl-2-butene) with methanol (MeOH). The isobaric vapor liquid equilibrium data (T-x-y) for the binary mixtures of 2-methyl-2-butene and TAME, 2-methyl-1-butene and TAME are experimentally determined at 101.3 kPa. The study performed gives a thorough determination of the whole binary system equilibrium data by means of a dynamic ebullometer Fisher 602 VLE. The analysis of both liquid and vapour phases were performed using a HP 5890 Series II Plus Gas Chromatograph with FID detector.

A novel dynamic recirculating apparatus for vapour–liquid equilibrium measurements at moderate pressures and temperatures

A novel dynamic recirculating apparatus has been constructed for the measurement of isobaric and isothermal vapour–liquid equilibrium (VLE) measurements for pressures up to 750kPa and temperatures up to 600K. The apparatus has been constructed from 316 stainless steel (SS) and features Pyrex sight glasses in strategic positions to allow for the observation of flow patterns and circulation rates. The capabilities of the apparatus have been demonstrated through the measurement of pure component vapour pressures and binary vapour–liquid equilibrium data. Vapour pressure measurements were undertaken for cyclohexane, n-heptane, n-octane, ethanol and 1-propanol. Isobaric VLE data have been measured for the (cyclohexane+ethanol) system at pressures of 40.00, 69.81, 97.72 and 150.0 kPa and isothermal VLE data have been obtained for the (2-propanone+2-butanol) system at a temperature of 373.15K. The experimental azeotropic temperatures and compositions for the cyclohexane+ethanol isobaric data sets have been determined and correlated to linear functions. The experimental VLE data were correlated to the Wilson, NRTL and UNIQUAC models using the γ−ϕ approach with the truncated two-term virial equation of state (with the Hayden and O’Connell method for second virial coefficients). Thermodynamic consistency testing for the VLE data sets was performed with the Herington area test for the isobaric data and the point test of Van Ness and Fredenslund for the isothermal data.

Experimental Measurements and Correlations Isobaric Vapor-Liquid Equilibria for Water + Acetic Acid + Sec-butyl Acetate at 101.3 kPa

Isobaric vapor-liquid equilibrium(VLE) data for acetic acid + sec-butyl acetate and water + acetic acid + sec-butyl acetate systems were determined at 101.3 kPa using a modified Rose type. The nonideality of the vapor phase caused by the association of the acetic acid was corrected by the chemical theory and Hayden-O'Connell method. Thermodynamic consistency was tested for the binary VLE data. The experimental data were correlated successfully with the Non-Random Two Liquids (NRTL) model. The Root Mean Square Deviation (RMSD) of the ternary system was 0.0038. The saturation vapor pressure of sec-butyl acetate at 329 to 385 K was measured by means of two connected equilibrium cells. The vapor pressures of water and sec-butyl acetate were correlated with the Antoine equation. The binary interaction parameters and the ternary VLE data were obtained from this work.

Isobaric Vapor–Liquid Equilibrium Data for Binary System of Glycerol Ethyl Acetal and Acetonitrile at 60.0 kPa and 97.8 kPa

Isobaric vapor–liquid equilibrium (VLE) data for the binary mixture of glycerol ethyl acetal (GEA) and acetonitrile were measured at 60.0 kPa and 97.8 kPa, using a dynamic recirculating still. The VLE data were correlated using the nonrandom two-liquid (NRTL) and universal quasichemical activity coefficient (UNIQUAC) models, and the interaction parameters of this mixture were estimated. The experimental procedure was checked by measuring VLE data at 97.8 kPa of the well-known system acetone/methanol showing high conformity, as given by applying a set of VLE consistency tests. The vapor pressure of GEA was measured, for the first time, in the temperature range from 371.85 K to 456.85 K, and it is described by the following expression: ln PGEAsat(Pa) = 24.17 – 5781/T(K). The information collected is of utmost importance for the purification of GEA synthesized using simulated moving bed reactor technology.

Isobaric Vapor–Liquid Equilibria for the Binary and Ternary Systems of 2-Methyl-1-butanol, 2-Methyl-butanol Acetate, and Dimethylformamide (DMF) at 101.3 kPa

Isobaric vapor–liquid equilibrium data (VLE) for two binary systems, 2-methyl-1-butanol (1) + dimethylformamide (DMF) (3) and 2-methyl-butanol acetate (2) + DMF (3), and the ternary system 2-methyl-1-butanol (1) + 2-methyl-butanol acetate (2) + DMF (3) were measured in a modified Rose recirculation still at 101.3 kPa. Wilson and nonrandom two-liquid (NRTL) models were applied to correlate the binary systems’ VLE data, which had been examined by thermodynamic consistency test in the first place, and the model parameters were obtained. These parameters were used to predict the ternary VLE data, which yielded a good agreement with the experimental values.

Isobaric vapor–liquid equilibrium data for the binary system methyl acetate + isopropyl acetate and the quaternary system methyl acetate + methanol + isopropanol + isopropyl acetate at 101.3 kPa

Isobaric vapor–liquid equilibrium(VLE) data for the quaternary system methyl acetate+methanol+isopropanol+isopropyl acetate and the constituent binary system methyl acetate+isopropyl acetate have been determined at 101.3kPa with a modified Rose still. The rest of binary systems VLE data were obtained from the literature. The measured experimental data were found to be thermodynamically consistent according to the Herington analysis. Experimental binary data have been correlated by Wilson, NRTL and UNIQUAC activity coefficient models. The three models with their best-fitted parameters were used to predict the quaternary vapor–liquid equilibrium. A comparison of performances was made by using the criterion of average absolute deviations in boiling point and in vapor-phase composition. The results showed that the NRTL model yielded a good prediction for the quaternary system from the parameters of the correlated binary systems.

Isobaric vapor–liquid equilibrium data of the binary systems of octane with p, o, m-xylene at 20 kPa

Isobaric vapor–liquid equilibrium (VLE) data were determined at 20kPa for the three binary mixtures composed of octane+p, o, m-xylene by using a recirculation type still. All the data passed the thermodynamics test and no azeotropic behavior was observed. The experimental results were used as a basis to check the validity of two predictive models, the UNIFAC (DORTMUND) and COSMO-RS. These new VLE data were also correlated with the Wilson, NRTL, and UNIQUAC activity coefficient models.

Isobaric Vapor–Liquid Equilibrium Data for the System of 1-Methyl-2-Ethylbenzene + 1,2,4-Trimethylbenzene at 10 kPa

Vapor–liquid equilibrium (VLE) data of 1-methyl-2-ethylbenzene (1M2EB) + 1,2,4-trimethylbenzene (124TMB) at 10 kPa were measured by using a modified Rose–Williams type recirculation still. The thermodynamic consistency of the VLE data was examined by the Herrington and Fredenslund methods. Experimental data were correlated by the Wilson, nonrandom two-liquid (NRTL), and universal quasichemical activity coefficient (UNIQUAC) models. All of the models were satisfactorily correlated with the VLE data. The result showed that the UNIQUAC model was slightly more suitable to correlate the experimental data and no azeotropic behavior was observed.

Isobaric vapor–liquid equilibrium (VLE) for pinane, dihydromyrcene (DHM) and dihydromyrcenol (DHMOH) at 6 kPa

The isobaric VLE data for three binary systems (DHM+pinane, DHM+DHMOH, pinane+DHMOH) and one ternary system (pinane+DHM+DHMOH) at 6kPa were measured with a Rose-Williams still. The binary VLE data were correlated with the Wilson and NRTL models. With the obtained model parameters, the ternary (pinane+DHM+DHMOH) VLE data was predicted and compared with the experimental data and the result shows that the parameters also have a good performance in the prediction of the ternary VLE data.

Phase equilibria for the ternary systems ethanol, water + ethylene glycol or + glycerol at 101.3 kPa

Two solvents, ethylene glycol and glycerol, are proposed as possible entrainers for the extractive distillation of the binary azeotropic mixture formed by ethanol and water. In this way, consistent isobaric vapour–liquid equilibrium data at 101.3kPa were measured for the ternary systems ethanol+water+ethylene glycol and ethanol+water+glycerol. The data were correlated by local compositions models Wilson, NRTL and UNIQUAC. Parameters of these models were later employed to evaluate ability of the candidates to break the original azeotrope. The obtained results led to consider the ethylene glycol and the glycerol as valid entrainers for the extractive distillation process of ethanol and water.

Influence of a microwave irradiation field on vapor–liquid equilibrium

Based on the modified Othmer still, an instrument is developed for vapor–liquid equilibrium (VLE) measurements in a microwave field. The isobaric conventional binary VLE experimental data compare favorably with the literature data and the results predicted from the universal quasi-chemical (UNIQUAC) model, which also verifies the reliability of the new instrument. A systematic experimental study of the effects of a microwave field on the VLE for the binary mixtures is reported herein for the first time to the best of the author's knowledge. Isobaric VLE data for two binary systems, benzene/ethanol and DOP/iso-octanol, at 101.33kPa are determined under conventional conditions and various microwave fields. The results clearly demonstrate that the VLE of benzene/ethanol in a microwave field is shifted compared to the conventional condition; no change is observed in the DOP/iso-octanol binary system. It is concluded that the ethanol can be vaporized selectively because the rate of microwave energy absorption of ethanol is higher than the rate of heat transfer from ethanol to benzene. Furthermore, various microwave irradiation powers and the dielectric constants of the binary mixture are chosen to investigate the influence of the microwave irradiation on the VLE. The results indicate that microwave field strengths from 25W to 200W have varying effects on the VLE. The results also show that the effect of the microwave field on VLE is more prominent in the binary system with a larger dielectric constant difference between the two substances.

Isobaric Vapor-Liquid Equilibrium for Ethyl Acetate-Isopropanol-1-Octyl-3-Methylimidazolium Tetrafluoroborate

Abstract: In order to study the possibility of separating ethyl acetate and isopropanol by extractive distillation with ILs as an entrainer. Isobaric vapor-liquid equilibrium data for ethyl acetate + isopropanol+1-octyl-3-methylimidazolium tetrafluoroborate ([OMIM]BF4) ternary system at 101.32 kPa were determined using a recirculating still. The results showed that the ionic liquid (IL) studied produced a notable salting-out effect, which enhanced the relative volatility of ethyl acetate to isopropanol and eliminated the azeotrope when the mole fraction of IL in the liquid phase was greater than 0.10. Therefore, [OMIM]BF4 can be used as the extraction agent of extractive distillation for ethyl acetate + isopropanol systerm, the suitable mole fraction of [OMIM]BF4 is about 20%. The experimental data were correlated with the NRTL model, the correlated results agreed well with the experimental data.

Vapor–Liquid Equilibrium for the 2-Ethoxyethanol–2-Ethoxyethyl Acetate System

Isobaric vapor–liquid equilibrium data for pure components as well as binary mixtures of 2-ethoxyethanol–2-ethoxyethyl acetate was generated using a modified ebulliometer. Measurements are reported...

Isobaric Vapor–Liquid Equilibria of Tertiary Amine and n-Alkane/Alkanol Binary Mixtures: Experimental Measurements and Modeling with GC-PPC-SAFT

New isobaric vapor–liquid equilibria data were measured for N,N-dimethyl-1-butanamine + n-hexane, n-heptane, 1-propanol, 1-butanol, or 1-pentanol and N,N-dimethyl-1-octanamine + n-heptane or 1-butanol binary mixtures. The boiling temperatures of both pure amines were also investigated. For this, an ebulliometer based on Cottrell’s apparatus was used. Thus, 180 new mixture data points displayed on 35 isobars were obtained in a pressure range from (29.84 to 99.83) kPa and in the full composition range. The experiments were compared with the Group contribution polar perturbed chain statistical associating fluid theory (GC-PPC-SAFT) equation of state predictions for pure amines and the mixtures containing an alkane. In the case of the systems containing an alkanol, the binary interaction parameters needed to be fitted.

Computation of Isobaric Vapor-Liquid Equilibrium Data for Binary and Ternary Mixtures of Methanol, Water, and Ethanoic Acid from T, p, x, and HmE Measurements

Vapor-liquid equilibrium (VLE) data for the strongly associated ternary system methanol + water + ethanoic acid and the three constituent binary systems have been determined by the total pressure-temperature-liquid-phase composition-molar excess enthalpy of mixing of the liquid phase (p, T, x, HmE) for the binary systems using a novel pump ebulliometer at 101.325 kPa. The vapor-phase compositions of these binary systems had been calculated from Tpx and HmE based on the Q function of molar excess Gibbs energy through an indirect method. Moreover, the experimental T, x data are used to estimate nonrandom two-liquid (NRTL), Wilson, Margules, and van Laar model parameters, and these parameters in turn are used to calculate vapor-phase compositions. The activity coefficients of the solution were correlated with NRTL, Wilson, Margules, and van Laar models through fitting by least-squares method. The VLE data of the ternary system were well predicted from these binary interaction parameters of NRTL, Wilson, Margules, and van Laar model parameters without any additional adjustment to build the thermodynamic model of VLE for the ternary system and obtain the vapor-phase compositions and the calculated bubble points.

Isobaric Vapor–Liquid Equilibrium Data of 2-Methyl-propan-2-ol (1) + Heptan-1-ol (2), Methanol (1) + Heptan-1-ol (2), Ethanol (1) + Heptan-1-ol (2), and Propan-1-ol (1) + Heptan-1-ol (2) at 96.5 kPa

Isobaric vapor–liquid equilibrium data at a local atmospheric pressure of 96.5 kPa is reported for the four binary systems, namely, 2-methyl propan-2-ol (1) + heptan-1-ol (2), methanol (1) + heptan-1-ol (2), ethanol (1) + heptan-1-ol (2), and propan-1-ol (1) + heptan-1-ol (2). The experiments are done using a Swietoslawski-type ebulliometer. The liquid-phase activity coefficients are modeled using the well-established Wilson model and the universal functional (UNIFAC) group contribution method. The data are found to be thermodynamically consistent.

Isobaric Vapor–Liquid Equilibrium Data for Binary Mixtures of 1-Phenylethanone with a Few Alcohols at 95.2 kPa

Bubble point temperatures at atmospheric pressure of 95.2 kPa are measured for the binary systems propan-1-ol (1) + 1-phenylethanone (2), propan-2-ol (1) + 1-phenylethanone (2), 2-methyl-1-propanol (1) + 1-phenylethanone (2), and 2-butanol (1) + 1-phenylethanone (2) using a Swietoslawski-type ebulliometer. The liquid-phase mole fraction, x1, versus bubble point temperature, T, measurements are found to be well represented by the Wilson model. The optimum Wilson parameters are used to calculate the vapor-phase composition, activity coefficients, and excess Gibbs free energy and the results compared with the values of activity coefficients of the mixtures calculated using the UNIFAC group contribution method. The results are discussed.

Isobaric vapor-liquid equilibrium for toluene, 3-methylthiophene and N-formylmorpholine at 101.33 kPa

Isobaric vapor-liquid equilibrium (VLE) data were measured for binary mixtures of toluene+N-formylmorpholine, toluene+3-methylthiophene and 3-methylthiophene+N-formylmorpholine at 101.33 kPa. The VLE data of the binary systems were found to be thermodynamically consistent. The saturated vapor pressure calculated by CSGC-PR equation of the pure component had higher accuracy than that calculated by Antoine equation. The liquid-phase activity coefficients of the binary systems were calculated by the Wilson, NRTL and UNIFAC models, and the binary interaction parameters of the three models were determined by the VLE data. The Wilson model was selected as the most suitable model to predict the VLE data of the ternary system of toluene+3-methylthiophene+Nformylmorpholine. The relative volatility between toluene and 3-methylthiophene was also calculated. Moreover, the effect of N-formylmorpholine as solvent was studied. When the molar ratio of solvent to feed (S/F) was 7, the relative volatility reached 1.904, which is almost twice the relative volatility without solvent. Therefore, N-formylmorpholine can be considered as an effective extracting agent for the separation of the close-boiling mixture of toluene+3-methylthiophene by extractive distillation.