Vapor-Liquid Equilibria in the Systems Ethyl 1,1-Dimethylethyl Ether + Cyclohexane and + Benzene at 94.00 kPa

Abstract

Consistent vapor-liquid equilibria for the binary systems of ETBE with benzene and cyclohexane at 94.00 kPa have been measured. Both systems show slightly positive deviation from ideal behavior and do no present azeotropic behavior. The activity coefficients and boiling points of the solutions were correlated with its mole fractions by the Redlich-Kister, Wohl, Wilson, UNIQUAC, NRTL, and Wisniak -Tamir equations. The data were also compared with UNIFAC predictions.     

Isobaric Phase Equilibria in the Binary Systems Ethyl 1,1-Dimethylethyl Ether + 1-hexene and + Cyclohexene at 94.00 kPa

Abstract

Consistent vapor-liquid equilibrium has been determined for the binary systems 1-hexene + ethyl 1,1-dimethylethyl ether (ETBE) and ethyl 1,1-dimethylethyl ether + cyclohexene at 94.00 kPa. The two systems present slight positive deviations from ideal behavior, can be considered to behave like regular solutions and do not present azeotropic behavior. Pure component vapor pressures are also reported for 1-hexene and cyclohexene. The phase equilibrium of the systems was correlated well by the Wilson, UNIQUAC, and NRTL models and reasonably predicted by the UNIFAC group contribution method. The boiling points of the binary systems were correlated with the Wisniak-Tamir equation.     

Phase Equilibria in the Systems Ethyl 1,1-Dimethylethyl Ether + Benzene + 2,2,4-Trimethylpentane and Benzene + 2,2,4-Trimethylpentane at 94.00 kPa

Abstract

Consistent vapor-liquid equilibria data at 94.00 kPa have been determined for the ternary system ethyl 1,1-dimethylethyl ether + benzene + 2,2,4-trimethylpentane and for its constituent binary benzene + 2,2,4-trimethylpentane, in the temperature range 343 to 370 K. The systems exhibit slight positive deviations from ideal behavior and the system benzene + 2,2,4-trimethylpentane presents an azeotrope. The VLE data have been correlated with the mole fraction using the Redlich-Kister, Wilson, NRTL, UNIQUAC, and Tamir relations. These models, in addition to UNIFAC, allow good prediction of the VLE properties of the ternary system from those of the pertinent binary systems.     

Phase Equilibria in the Ternary System Methyl 1,1-Dimethylethyl Ether + Benzene + Toluene

Abstract

Consistent vapor-liquid equilibrium data at 94kPa have been determined for the ternary system methyl 1,1-dimethylethyl ether (MTBE) + benzene + toluene. The results indicate that the system deviates positively from ideality and that no azeotrope is present. The ternary activity coefficients of the system have been correlated with the composition using the Redlich-Kister, Wilson, NRTL, UNIQUAC, and UNIFAC, models. It is shown that most of the models allow a very good prediction of the phase equilibrium of the ternary system using the pertinent parameters of the binary systems. In addition, the Wisniak-Tamir relations were used for correlating bubble-point temperatures.     

Phase Equilibria in the Systems Oxolane + Vinyl Acetate,Oxolane + Ethyl 1,1-Dimethylethyl Ether and Vinyl Acetate + Ethyl 1,1-Dimethylethyl Ether

Abstract

Vapor-liquid equilibrium at 94kPa has been determined for the binary systems oxolane (THF) + vinyl acetate, oxolane + ethyl 1,1-dimethylethyl ether (ETBE) and vinyl acetate + ethyl 1,1-dimethylethyl ether. The three systems present slight to moderate positive deviations from ideal behavior and, to a first approximation, can be considered to behave like regular solutions. An azeotrope is present in the system vinyl acetate + ETBE that boils at 340.40 K and contains 49.8% mol vinyl acetate. The activity coefficients of the systems were correlated reasonable well with its composition by the Wohl, Wilson, UNIQUAC and NRTL models. The boiling points of the binary systems were correlated with the Wisniak-Tamir equation.     

Isobaric Vapor-Liquid Equilibria and Densities for the System Ethyl 1,1-Dimethylethyl Ether + 2-Propanol

Vapor-liquid equilibrium (VLE) data at 50, 75, and 94 kPa have been determined for the binary system ethyl 1,1-dimethylethyl ether + 2-propanol, in the temperature range 323-344 K. The measurements were made in an equilibrium still with circulation of both the vapor and liquid phases. Excess volumes have been also determined from density measurements at 298.15 K. The system exhibits positive deviation from ideal behavior and azeotropic behavior in the range of experimental pressures. The excess volume of the system is negative over the whole mole fraction range. The activity coefficients and boiling points of the solutions were well correlated with the mole fraction by the Wohl, Wilson, UNIQUAC, NRTL equations and predicted by the UNIFAC group contribution method. Excess volume data were correlated using the Redlich-Kister expansion.     

Isobaric Vapor-Liquid Equilibria and Densities for the Binary Systems Oxolane + Ethyl 1,1-Dimethylethyl Ether,Oxolane + 2-Propanol and Propan-2-One + Trichloromethane

Vapor-liquid equilibrium data have been determined at 50 kPa for the binary systems oxolane (THF) + ethyl 1,1-dimethylethyl ether (ETBE) and oxolane + 2-propanol, and at 94 kPa for the system propan-2-one + trichloromethane. Excess volumes have also been determined from density measurements at 298.15 K. The systems oxolane + ethyl 1,1-dimethylethyl ether and oxolane + 2-propanol exhibit slight to moderate positive deviations from ideal behavior and no azeotrope is present. The system propan-2-one + trichloromethane exhibits negative deviations from ideal behavior and presents an azeotrope. The excess volumes of the system oxolane + ethyl 1,1-dimethylethyl ether are negative over the whole mole fraction range while those of the system oxolane + 2-propanol are positive. Excess volumes of the system propan-2-one + trichloromethane, change from negative to positive as the concentration of propan-2-one increases. The activity coefficients and boiling points of the solutions were correlated with the mole fraction by the Wohl, Wilson, UNIQUAC, and NRTL equations, and predicted by the UNIFAC group contribution method. Excess volume data were correlated using the Redlich-Kister expansion. The chemical association theory was applied for explaining the equilibrium behavior of the systems oxolane + 2-propanol and propan-2-one + trichloromethane.     

Vapor-Liquid Equilibria in the Binary System Formed by Methyltertiarybutylether with Benzene at 490 and 709 mm Hg

Abstract

Isobaric vapor-liquid equilibria over the entire composition range are obtained from the measurement of the liquid phase composition versus boiling temperatures by means of a Swietoslawski type ebulliometer at 490 and 709 mm Hg for the methyl-tertiary-butylether(1) + benzene(2) system. The experimental composition (x) versus temperature (t) values could be represented well by both the Wilson and NRTL models. The optimum Wilson parameters have been used to calculate the excess Gibbs free energy.     

Liquid–Liquid Equilibria of Oxygenate Fuel Additives with Water at 298.15 K: Ternary and Quaternary Aqueous Systems of Diisopropyl Ether and Hydrocarbons with 2-Propanol

Experimental tie-line data were determined for one ternary system, water + diisopropyl ether + n-heptane and two quaternary systems, water + diisopropyl ether + 2-propanol + n-heptane or toluene at 298.15 K and ambient pressure. The experimental liquid–liquid equilibrium data were successfully correlated using a modified UNIQUAC model with ternary and quaternary mixture parameters, in addition to the binary ones. The calculated results were also compared with those obtained from an extended UNIQUAC model of Nagata [Fluid Phase Equilib. 54, 191 (1990)].     

Solid-liquid Equilibria in the Ternary System (NaCl+SrCl2+H2O) and (KCl+SrCl2+H2O) at 288.15 K and 0.1 Mpa

Solid-liquid phase equilibria of the two ternary systems (NaCl+SrCl₂+H₂O) and (KCl+SrCl₂+H₂O) at T=288.15 K and p=0.1 MPa were studied using the isothermal dissolution equilibrium method. Solubilities of the equilibrium liquid phase were determined, and the solids were also investigated by the Schreinemaker method of wet residues. In the ternary system (NaCl+SrCl₂+H₂O) at 288.15 K, there is one invariant point corresponding to (NaCl+SrCl₂·6H₂O) and two crystallization regions corresponding to NaCl and SrCl₂·6H₂O. The crystallized area of SrCl₂·6H₂O decreased with the increasing temperature, while that of NaCl increased slightly. In the ternary system (KCl+SrCl₂+H₂O) at 288.15 K, there is one invariant point(KCl+SrCl₂·6H₂O) and two crystallization regions corresponding to KCl and SrCl₂·6H₂O. Both systems belong to a simple eutectic type, and neither double salts nor solid solutions were formed. On the basis of Pitzer-Harvie-Weare model, the solubilities of the two systems at 288.15 K were demonstrated. A comparison showed that the calculated solubilities agreed well with the experimental data.     

Cationic Heteroconjugation Constants in the OHN+ and NHO+ Systems in Propylene Carbonate: Dependence on Difference in Basicity

Cationic heteroconjugation equilibria of more than ninety systems consisting of substituted pyridines, their N-oxides, and trimethylamine N-oxide, i. e., in systems with mixed hydrogen bridges of type OHN⁺ (NHO⁺) were studied in propylene carbonate. Both experimental systems without proton transfer, BH⁺/B₁, and those with proton transfer, B₁H⁺/B, were explored. The stability of the mixed hydrogen bridges, OHN⁺ (NHO⁺), is compared with that of the OHC⁺-type bridges. The influence of the difference in basicity of the conjugate base of the proton donor and the proton acceptor on the presence of the proton transfer equilibria, and, consequently, the possibility of determination of the cationic heteroconjugation constant values is discussed.