Binary System Carbon Dioxide Research Articles

High-pressure phase behavior of systems with ionic liquids: II. The binary system carbon dioxide+1-ethyl-3-methylimidazolium hexafluorophosphate

In this work the phase behavior of a binary mixture consisting of a supercritical fluid and an imidazolium-based ionic liquid (IL) was studied experimentally. Carbon dioxide was selected as the supercritical fluid and 1-ethyl-3-methylimidazolium hexafluorophosphate was considered as the IL. A synthetic method was used to measure vapor–liquid boundaries. Results are reported for carbon dioxide concentrations ranging from 10.4 up to 61.9 mol%, and within temperature and pressure ranges of 308.14–366.03 K and 1.49–97.10 MPa, respectively. Also, the experimental results obtained in this work were compared with other available binary systems of supercritical fluid+IL.

Vapor–liquid equilibrium data for the carbon dioxide (CO 2) + difluoromethane (R32) system at temperatures from 283.12 to 343.25 K and pressures up to 7.46 MPa

Isothermal vapor–liquid equilibrium (VLE) data have been measured for the binary system carbon dioxide (CO 2)+difluoromethane(R32) at eight temperatures between 283.12 and 343.25 K, and at pressures in the range 1.11–7.46 MPa. The experimental method used in this work is of the static-analytic type, taking advantage of two pneumatic capillary samplers (Rolsi™, Armines’ Patent) developed in the Cenerg/TEP laboratory. The data were obtained with uncertainties within ±0.02 K, ±0.002 MPa, and ±1% for molar compositions. The isothermal P, x, and y data are well represented with the Peng–Robinson equation of state (PR EoS) using the Mathias Copeman alpha function and the Wong–Sandler mixing rules involving the NRTL model.

Styrene–carbon dioxide phase equilibria at high pressures

High pressure vapor–liquid equilibrium data for the binary system styrene and carbon dioxide were measured using the static method. Experiments were carried out at temperatures and pressures between 333.15 and 348.15 K, and 6 and 13 MPa, respectively. Experimental results were correlated with the Peng–Robinson equation of state using conventional mixing rules with one interaction parameter.

High-pressure phase behavior of systems with ionic liquids: Part III. The binary system carbon dioxide + 1-hexyl-3-methylimidazolium hexafluorophosphate

The phase behavior of a binary mixture consisting of a supercritical fluid and an imidazolium-based ionic liquid was studied experimentally. Carbon dioxide and 1-hexyl-3-methylimidazolium hexafluorophosphate were the selected supercritical fluid and ionic liquid, respectively. A synthetic method was used to measure vapor-liquid boundaries. Results are reported for carbon dioxide concentrations ranging from 9.8 to 72.7 mol% and within temperature and pressure ranges of 298.31–363.58 K and 0.64–94.60 MPa, respectively. The experimental results obtained in this work were compared with phase behavior data of the binary system of carbon dioxide together with another member of the same homologous ionic liquid family (1-ethyl-3-methylimidazolium hexafluorophosphate). The CO 2 + [hmim][PF 6] binary system has a two-phase region liquid–vapor extending up to very high pressures.

High-Pressure Vapor−Liquid Equilibria in the System Carbon Dioxide and 2-Propanol at Temperatures from 293.25 K to 323.15 K

Isothermal (P, T, x, y) data have been measured for the binary system carbon dioxide + 2-propanol at temperatures from (293 to 323) K. The pressure range under investigation was between (0.68 and 8.6) MPa. The new experimental data are correlated with the Soave−Redlich−Kwong (SRK) equation of state coupled with the HVID mixing rules. A correlation of the HVID parameters with temperature is proposed by using all reliable published data and those of this study.

Measurement and modelling of bubble and dew points in the binary systems carbon dioxide + cyclobutanone and propane + cyclobutanone

The fluid phase behaviour for the binary systems carbon dioxide+cyclobutanone and propane+cyclobutanone has been determined experimentally, using Cailletet equipment. For both the systems bubble points have been determined for a number of isopleths covering the whole mole fraction range. Additionally, for the binary system carbon dioxide+cyclobutanone dew points and critical points could be observed for a number of overall-compositions rich in carbon dioxide. The temperature and pressure range were, respectively, from 278 to 369 K and from 0.1 to 14.0 MPa. Correlation of the experimental data of both systems has been performed using the Soave–Redlich–Kwong (SRK) equation of state. Satisfactory results have been achieved using only one binary interaction parameter.

Isothermal vapor–liquid equilibria for binary mixtures of carbon dioxide with diethylene glycol (diethyl, butyl, hexyl, or dibutyl) ether at elevated pressures

Isothermal vapor–liquid equilibrium (VLE) phase compositions were measured for four binary systems of carbon dioxide with diethylene glycol diethyl ether, diethylene glycol butyl ether, diethylene glycol hexyl ether, and diethylene glycol dibutyl ether at temperatures from 333.15 to 413.15 K and pressures up to 20 MPa. The saturated vapor composition of the ethers follows the order of diethylene glycol diethyl ether>diethylene glycol butyl ether>diethylene glycol dibutyl ether>diethylene glycol hexyl ether, while the solubility of carbon dioxide in the liquid obeys the sequence of diethylene glycol diethyl ether≈diethylene glycol dibutyl ether>diethylene glycol hexyl ether ≈ diethylene glycol butyl ether. Henry’s constants were calculated by fitting the Krichevsky–Ilinskaya (KI) equation to the isothermal equilibrium data. The constants increase with increasing temperature for each binary system. The new phase equilibrium data were correlated with several cubic equations of state with the van der Waals one-fluid mixing rules. Generally the Peng–Robinson (PR) equation of state with two binary interaction parameters yielded the best results.

Phase equilibria of carbon dioxide with phenol and diphenyl carbonate

We report the vapor–liquid equilibria (VLE) of the two binary systems (carbon dioxide–phenol) and (carbon dioxide–diphenyl carbonate (DPC)). The bubble points are measured using a Cailletet apparatus in the temperature range 70–180 °C and pressures up to 130 bar. The experimental data are adequately represented by the Peng–Robinson equation of state (PR EOS) with quadratic mixing rules. The two binary interaction parameters k ij and l ij are obtained by fitting, and were found to have a linear dependency with temperature. The data available from literature for the CO 2–phenol system could also be predicted very well by the same model and parameter values.

Compressed Liquid Densities and Excess Volumes for the Binary Systems Carbon Dioxide + 1-Propanol and Carbon Dioxide + 2-Propanol Using a Vibrating Tube Densimeter up to 25 MPa

The PvT behavior was determined for the binary systems carbon dioxide + 1-propanol and carbon dioxide + 2-propanol in the homogeneous state. The measurements were performed for different compositions at temperatures ranging from 313 to 363 K and pressures up to 25 MPa using a vibrating tube densimeter. The accuracy of the density determinations was better than ±0.05%, and the densities presented in this work agree well with data reported in the literature. The excess volumes were calculated from the experimental PvT data.

Measurements and modeling of bubble points in binary carbon dioxide systems with tetrahydropyran and methylcyclohexane

Using a Cailletet apparatus, bubble points in the binary systems of carbon dioxide with methylcyclohexane and tetrahydropyran, were measured. The temperature ranges from 263 up to 353 K, and pressures from 0.4 up to 11.5 MPa were applied. The experimental results were modeled using the predictive Soave–Redlich–Kwong and Universal-Quasi-Chemical (PSRK/UNIQUAC) method. The lacking binary interaction parameters of the UNIQUAC model were evaluated and reported. The average absolute deviations between the experimental and predicted bubble point pressures are 1.53 and 1.72% for the carbon dioxide + methylcyclohexane and the carbon dioxide + tetrahydropyran systems, respectively.

Isothermal vapor–liquid equilibria of binary systems of carbon dioxide and 1-butyne, compared to other binary CO2 + C4Hn systems in terms of global parameters

Isothermal vapor–liquid equilibria have been measured for binary systems carbon dioxide and 1-butyne at 303, 313, and 333 K. In advance, the accuracy of the experimental method was checked with the binary system carbon dioxide+n-butane in comparison to literature data. The measurements were performed using an analytical method with a recirculation view cell apparatus. The experimental data were correlated with the Peng–Robinson equation of state. The interaction parameters kij of the binary systems of carbon dioxide and n-butane, isobutane, 1-butene, and 1,3-butadiene were calculated and compared. The kij-values turned out to decrease with increasing degree of unsaturation of the hydrocarbons. The binary mixtures of carbon dioxide with C4-hydrocarbons were located in a global phase diagram calculated for the Peng–Robinson equation of state for the first time here. The analysis of the global phase diagram shows that the unsaturation of the C4 molecules has a quantitative effect on the phase behaviour in contrast, for example, to the chain length effect.

Vapor−Liquid Equilibrium for Binary Systems of Carbon Dioxide + Methanol, Hydrogen + Methanol, and Hydrogen + Carbon Dioxide at High Pressures

Vapor−liquid equilibrium data and density of the liquid phase for binary systems of carbon dioxide + methanol, hydrogen + methanol, and carbon dioxide + hydrogen at high pressures were determined. A dynamic technique with liquid-phase recirculation and on-line gas chromatography was used in this study. The equilibrium data and density were measured at temperatures between 278.15 K and 308.15 K, and pressures between 15 bar and 192.53 bar. The isothermal volume expansion behavior for the carbon dioxide + methanol system at various temperatures was also determined.

Isothermal Vapor−Liquid Equilibria of the Carbon Dioxide (CO2)−N,N-Dimethylformamide (DMF) System at Temperatures from 293.95 K to 338.05 K and Pressures up to 12 MPa

Vapor−liquid equilibrium data are presented for the binary system carbon dioxide−N,N-dimethylformamide at 293.95, 313.05, and 338.05 K and pressures up to 12 MPa. The data are correlated using the Peng−Robinson equation of state with Wong−Sandler mixing rules. Agreement between the calculated and the measured equilibrium data has been found within 0.03% for vapor mole fractions and within 0.6% for pressures.

Isothermal Vapor−Liquid Equilibria for Binary Mixtures of Carbon Dioxide with Hexyl Acetate, Cyclohexyl Acetate, or Phenyl Acetate at Elevated Pressures

Isothermal vapor−liquid equilibrium phase compositions were measured for three binary systems of carbon dioxide with different C6-acetateshexyl acetate, cyclohexyl acetate, and phenyl acetateat temperatures from 333.15 K to 413.15 K and pressures up to 20 MPa. The solubility isotherm of the acetates in the vapor phase exhibits a minimum value at subcritical pressures of carbon dioxide. Henry's constants were calculated by fitting the Krichevsky−Ilinskaya equation to the isothermal equilibrium data. The constants increase with increasing temperature for these three binary systems. The new phase equilibrium data were correlated with the Soave−Redlich−Kwong, the Peng−Robinson, and the Patel−Teja equations of state. The Peng−Robinson equation with two-parameter (ka12 and kb12) van der Waals mixing rules is marginally better than other methods for the investigated systems.

Bubble-point pressures of the binary system carbon dioxide+linalool

A synthetic method was used to investigate high-pressure vapor–liquid equilibria of the binary system carbon dioxide+linalool. The bubble points of this system were measured at carbon dioxide mole fractions from 0.2 up to 0.993 and within temperature and pressure ranges of 283–371 K and 1.4–14.7 MPa, respectively. Critical points of this binary system were also determined experimentally for a carbon dioxide mole fraction range from 0.93 up to 0.993. The results were correlated by the Stryjek–Vera modified version of the Peng–Robinson equation of state using one-fluid van der Waals mixing rules with both one and two interaction parameters.

High-pressure (vapor+liquid) equilibrium in binary mixtures of (carbon dioxide+water or acetic acid) at temperatures from 313 to 353 K

Experimental results for the high-pressure (vapor+liquid) equilibrium of binary systems of carbon dioxide+(either water or acetic acid) are reported for temperatures from 313 to 353 K and pressures between 1 and 14 MPa. The experimental results are correlated using the modification of Melhem et al. [G.A. Melhem, R. Saini, B.M. Goodwin, A modified Peng–Robinson equation of state, Fluid Phase Equilibr. 47(1989) 189] for the Peng–Robinson equation of state and the mixing rule of Panagiotopoulos and Reid [A.Z. Panagiotopoulos, R.C. Reid, Equations of state: theories and applications, in: K.C. Chao, R.L. Robinson (Eds.), ACS Symposium Series, vol. 300, American Chemical Society, Washington, DC 1986 pp. 571]. The correlation of the experimental data for (carbon dioxide+water) required temperature-dependent binary interaction parameters. Correlating the data for (carbon dioxide+acetic acid) was not very successful as long as the dimerization of acetic acid was neglected. However, including dimerization resulted in a reliable correlation and even a successful prediction of the high-pressure (vapor+liquid) equilibrium from pure component data alone.

Supercritical fluid extraction of solids. Statistical thermodynamic approachZ

To study the effect of non-sphericity of solvent and solute molecules on the main characteristics of supercritical fluid extraction we consider the fourth-order virial expansion in which the individual virial coefficients (and cross terms) were determined from the formula proposed recently for the Kihara generalized pair potential. The Kihara four-step square-well potential was assumed; its form makes it possible to write analytic expressions for the considered virial coefficients and, consequently, for the main thermodynamic functions—the residual chemical potential of solute and total pressure. The method is applied to determine the dependence of the mole fraction of solute on temperature or pressure in the binary systems carbon dioxide–naphthalene and ethylene–naphthalene and the effect of the cosolvent on the solute concentration in the system ethylene–naphthalene–acetone at 308 K. Fair agreement with the simulation and experimental data was found.

Experimental Pressure−Temperature Data on Three- and Four-Phase Equilibria of Fluid, Hydrate, and Ice Phases in the System Carbon Dioxide−Water

Pressure−temperature data of three-phase lines, quadruple points, and critical end points of the binary system carbon dioxide−water were taken in a high-pressure view cell at temperatures between 270 and 305 K and pressures up to 7.4 MPa. The phase equilibria involve both fluid (liquid and vapor) phases and solid phases (hydrate and ice). The present results are in good agreement with most data from the literature. Correlations of the experimental data with Clausius−Clapeyron type equations are given. The literature data are reviewed critically in comparison to the correlations. The global phase behavior of the system carbon dioxide−water is discussed and compared to the phase behavior of similar binary systems.

Vapor–liquid equilibria for binary mixtures of carbon dioxide with 1,2-dimethoxybenzene, 2-methoxyphenol, or p-cresol at elevated pressures

Vapor–liquid equilibrium (VLE) phase compositions were measured for three binary systems of carbon dioxide with 1,2-dimethoxybenzene, 2-methoxyphenol, or p-cresol at temperatures from 323.15 to 423.15 K and pressures up to 20 MPa. The solubilities of these close-boiling heavy components in the vapor phase were compared over the experimental conditions. Henry's constants were calculated from the isothermal equilibrium data. The temperature effects on the Henry's constants and the solubilities of carbon dioxide in the liquid phase were discussed. The new phase equilibrium data were correlated by the Soave–Redlich–Kwong (SRK), the Peng–Robinson (PR), and the Patel–Teja (PT) equations of state (EOS) with the van der Waals (vdW) one-fluid mixing rules. The two-parameter ( k a 12 and k b 12 ) vdW mixing rule was found to yield satisfactory results for the investigated systems.

Vapor–liquid equilibria for the binary system of carbon dioxide and 1,3-butadiene at 303, 313 and 333 K

In this work, the vapor–liquid equilibria for the binary system carbon dioxide—1,3-butadiene was measured at three temperatures, 303, 313 and 333 K. The measurements were carried out analytically in a recirculation apparatus. The experimental data were correlated with a modified Peng–Robinson equation of state and the Predictive Soave–Redlich–Kwong model. At 311 K, a parallel was drawn with the binary systems of n-butane, isobutane, 1-butene and carbon dioxide by means of the distribution coefficients K( i).