José Martı́nez-Ageitos

Physical and equilibrium properties of diisopropyl ether+isopropyl alcohol+water system

Abstract Molar volume, isentropic compressibility, and molar refraction changes of mixing of the system diisopropyl ether (DIPE)+isopropyl alcohol (IPA)+water were determined at 298.15 K. These deviational properties were satisfactorily correlated with the composition data by means of Redlich–Kister polynomials. Tie line data have been determined at 298.15, 308.15, and 318.15 K for the ternary liquid–liquid equilibria, and were adequately correlated by means of the NRTL and UNIQUAC equation, and compared with results predicted by the UNIFAC method.

Physical aging for an epoxy network diglycidyl ether of bisphenol A/m-xylylenediamine

Abstract The physical aging of the epoxy network consisting of a diglycidyl ether of bisphenol A (BADGE n=0) and m-xylylenediamine (m-XDA) were studied by differential scanning calorimetry. The following aging temperatures have been used in this work: 60, 70, 80, 90, 100 and 110 °C. The glass transition temperature and the variation of the specific heat capacities have been calculated using the method based on the intersection of both enthalpy–temperature lines for glassy and liquid states. The endothermic aging peak, relaxation enthalpy and fictive temperature were also calculated for each aging temperature and aging time.

VLE for water + ethanol + 1-octanol mixtures. Experimental measurements and correlations

Abstract Molar excess Gibbs free energies ( G E RT ) for the ternary system water + ethanol + 1-octanol were evaluated from the corresponding isobaric (101.32 kPa) vapour-liquid equilibrium data. The ( G E RT - composition data were then correlated by means of the Redlich-Kister polynomial and the NRTL and UNIQUAC equations, using an optimized value of 5.50 for the q′ UNIQUAC area parameter of 1-octanol. The experimental data were compared with data predicted using the ASOG, UNIFAC and UNIFAC-Lyngby group contribution methods.

LLE data for the systems water + (methanol or ethanol) + n-amyl acetate

We report new experimental liquid-liquid equilibrium data for the ternary mixtures water + methanol + n-amyl acetate and water + ethanol + n-amyl acetate at 25, 35 and 45 °C, together with the results of fitting the data with UNIQUAC equations. The activity coefficients of water and the alcohol in water + (methanol or ethanol) mixtures were calculated using UNIQUAC parameters obtained from experimental data for each of a number of ternary mixtures including water and the alcohol in question.

(Vapour + liquid) equilibrium of (DIPE + IPA + water) at 101.32 kPa

Thermodynamically consistent (vapour + liquid) equilibrium data at 101.32 kPa have been determined for (diisopropyl ether + isopropyl alcohol + water) and its constituents (diisopropyl ether + isopropyl alcohol) and (isopropyl alcohol + water). The NRTL and UNIQUAC equations for the liquid phase activity coefficients were found to correlate better the experimental data. The ASOG and the original and modified UNIFAC group-contribution methods did not represent adequately the (vapour + liquid) equilibrium data of this study.

Water + ethanol + 2-methoxy-2-methylbutane : Properties of mixing at 298.15 K and isobaric vapour-liquid equilibria at 101.32 kPa

Abstract Excess molar volumes (VE) and deviations in molar refraction (ΔR) and isentropic compressibility (Δκs) upon mixing were determined for homogeneous mixtures of water + ethanol + 2-methoxy-2-methylbutane at 298.15 K and atmospheric pressure. These data were satisfactorily correlated by the Redlich-Kister polynomial. For the same mixtures, vapour-liquid equilibrium (VLE) data at 101.32 kPa were determined using a distillation apparatus recycling both liquid and vapour phases. The Wisniak-L-W and McDermott-Ellis tests confirmed these VLE data to be thermodynamically consistent, and they were satisfactorily correlated using the NRTL equation (with α = 0.3), and satisfactorily predicted using the UNIFAC-Lyngby model to estimate the liquid-phase activity coefficients.

Thermodynamic behaviour of ethanol+methanol+2-ethoxy-2-methylpropane system. Physical properties and phase equilibria

Abstract The densities, refractive indices and speeds of sound of ternary ethanol+methanol+2-ethoxy-2-methylpropane (ETBE) mixtures were determined at 298.15 K and atmospheric pressure, and were used to calculate the corresponding excess molar volumes and the deviations of the molar refractive index and isentropic compressibility from linear dependence on concentration. These excess and deviational quantities were best predicted by the equations of Radojkovic, Kohler and Jacob and Fitzner. Vapour–liquid equilibrium (VLE) data were obtained for the ternary system at 101.32 kPa, shown to pass thermodynamic consistency tests, correlated by means of the equations Wilson, NRTL and UNIQUAC, and compared with the results predicted by the ASOG-KT and original and modified UNIFAC methods and by the equations of Wilson, NRTL and UNIQUAC with interaction parameters obtained from data for the relevant binary systems. The agreement between the experimental data and the latter predictions was as good as was achieved by ASOG-KT and UNIFAC-Dortmund, which were the best of the group contribution methods.

Optimization of UNIQUAC structural parameters for individual mixtures; application to new experimental liquid-liquid equilibrium data for aqueous solutions of methanol and ethanol with isoamyl acetate

Abstract Arce, A., Blanco, A., Martinez-Ageitos, J. and Vidai, I., 1994. Optimization of UNIQUAC structural parameters for individual mixtures; application to new experimental liquid-liquid equilibrium data for aqueous solutions of methanol and ethanol with isoamyl acetate. Fluid Phase Equilibria 93; 285-295. Experimental liquid-liquid equilibrium data for the ternary mixtures water + methanol + isoamyl acetate and water + ethanol + isoamyl acetate at various temperatures are reported, together with the results of correlation by the original UNIQUAC equation using both structural parameters q and r from the literature and qs and rs optimized for each mixture as part of the overall correlation procedure. The improved fit obtained with the optimized parameters (which differed from the “universal” values only for the smaller molecules) may be viewed as being due to the active surface area and volume of a molecule being dependent upon its environment.

Measurement and prediction of isobaric vapour–liquid equilibrium data of the system ethanol+methanol+2-methoxy-2-methylpropane

Abstract Isobaric vapour–liquid equilibria for the system ethanol+methanol+MTBE were determined at 101.32 kPa. These data for this ternary system were then compared with predictions made using the Wilson, NRTL and UNIQUAC equations and the binary interaction parameters for the corresponding constituent binary subsystems. The predictions deviated only slightly from the experimental data. Moreover, these deviations were smaller than those obtained when the equilibrium data were predicted using the ASOG, UNIFAC, UNIFAC-Lyngby or UNIFAC-Dortmund group-contribution methods, among which the latter method afforded the most satisfactory predictions.

Phase equilibria involved in extractive distillation of 2-methoxy-2-methylpropane+methanol using 1-butanol as entrainer

Abstract Consistent vapour–liquid equilibrium (VLE) data at 101.32 kPa have been determined for the ternary system 1-butanol+methanol+2-methoxy-2-methylpropane, correlated by means of the Wilson, NRTL, and UNIQUAC equations, and compared with the results predicted by using the same equations with interaction parameters obtained from data for the relevant binary systems. The predictions deviated only slightly from the experimental data. The Wilson equation provided the most satisfactory prediction. Moreover, deviations were smaller than those obtained when the equilibrium data were predicted using the ASOG-KT and the original and modified UNIFAC group-contribution methods. The results obtained with a commercial simulator (ChemCAD IV) indicate that extractive distillation with 1-butanol as entrainer is a feasible method for the separation of 2-methoxy-2-methylpropane (MTBE) and methanol.