Measurement and prediction of (solid + liquid) equilibria of (alkanediamine + biphenyl) mixtures (original) (raw)
The vapour pressures of {ethanediamine (EDA) + water}, {1,2-diaminopropane (1,2-DAP) + water}, {1,3diaminopropane (1,3-DAP) + water} or {1,4-diaminobutane (1,4-DAB) + water} binary mixtures, and of pure EDA, 1,2-DAP, 1,3-DAP, 1,4-DAB, and water components were measured by means of two static devices at temperatures between (293 and 363) K. The data were correlated with the Antoine equation. From these data, the excess Gibbs function (G E ) was calculated for several constant temperatures and fitted to a fourth-order Redlich-Kister equation using the Barker's method. The {ethanediamine (EDA) + water}, and {1,2-diaminopropane (1,2-DAP) + water} binary systems show negative azeotropic behaviour. The aqueous solutions of EDA, 1,2-DAP, or 1,3-DAP exhibit negative deviations in G E for all investigated temperatures over the whole composition range whereas the (1,4-DAB + water) binary mixture shows negative G E for temperatures (293.15 < T/K < 353.15) and a sinusoidal shape for G E at T = 363.15 K.
Industrial & Engineering Chemistry Research, 2004
All are congruently melting compounds. Compound formation is attributed to a strong A-B interaction. The excess molar volumes, V m E , have been determined for these mixtures at 298.15 K and atmospheric pressure. The systems exhibit very large negative excess molar volumes, V m E , and excess molar enthalpies, H m E. The V m E curves are nearly symmetrical. Strong crossassociation between hydroxyl and amine groups (OH‚‚‚NH 2) is a dominant effect, and it causes high negative values of V m E and H m E and 1:1 congruently melting solid compounds at lower temperatures. Our experimental data on V m E and the literature data on H m E were treated in terms of the ERAS model, DISQUAC, and modified UNIFAC. The ERAS model consistently describes V m E and H m E of the studied mixtures.
Solid–liquid equilibria of the n-alkanes (n-oc-tadecane, n-eicosane, n-tetracosane, n-pentacosane, n-triacon-tane) in biphenyl were measured by DSC 7 (Perkin-Elmer). It was found that all systems are simple eutectic. The solubility of the biphenyl in n-alkanes was studied in the temperature range 301–370 K. The experimental results were correlated using modified UNIFAC (Larsen and Gmehling versions) and ideal models. Good representation of solubility diagrams was obtained using partly readjusted UNIFAC parameters of Larsen version. Taking into account the large range of applicability of UNIFAC and the predictions of the activity coefficients for many other components in different classes of mixtures, we can conclude that the new experimental data for the systems mentioned in this work should be included in the database used by UNIFAC in order to evaluate better interaction parameters and to improve predictions.
Solid–liquid equilibria of biphenyl binary systems
Solid–liquid equilibrium temperatures, obtained by means of a differential scanning calorimetry (DSC) technique , are reported for biphenyl + n-C 21 , or +n-C 31 , or +n-C 41 systems. Biphenyl + alkane, or +heterocyclic compound (diphenyl ether, dibenzofuran, indole, diphenylamine, 1-octadecanol or octadecanoic acid) have been investigated using DISQUAC and the ideal solubility model. This model provides good results for alkane solutions whose components which largely differ in size. Interactional effects are relevant in solutions with hep-tane, octadecane or mixtures involving dibenzofuran, indole, 1-octadecanol or octadecanoic acid.
Fluid Phase Equilibria, 2015
Isobaric vapor-liquid equilibria at p = 101.32 kPa (iso-p VLE) and the mixing properties, h E and v E , are determined for a set of twelve binary solutions: HCOOC u H 2u+1 (1)+C n H 2n+2 (2) with u = (1-4) and n = (7-9). The (iso-p VLE) present deviations from the ideal behavior, which augment as u diminishes and n increases. Systems with [u = 2,3 n = 7] and [u =4 , n = 7,8] present a minimum-boiling azeotrope. The nonideality is also reflected in high endothermic values, h E > 0, and expansive effects, v E > 0, for all the binaries, which increase regularly with n. However, for a same hydrocarbon, the properties diminish with increasing u. This, in turn, causes the dipolar effect of the methanoates to decrease, with the resulting reduction in mixing effects. As a result, other interpretations on the behavioral structural model of these systems are established. Modeling of the experimental quantities is carried out using the authors' model with good results, and comparisons are made with an adapted version of the NRTL model. Energetic properties of the solutions are predicted with the UNIFAC group contribution model, but the values obtained are not as good. Hence, parameters corresponding to the specific interaction HCOO/CH 2 are recalculated using a wider database, resulting in slightly better values. COSMO-RS methodology is also employed to assess the energetic effects of the mixing process. Apart from some exceptions, also mentioned here, the method gives an acceptable estimation of the behavior of these systems. 2015 Elsevier B.V. All rights reserved.
Journal of Chemical & Engineering Data
Liquid-liquid equilibrium (LLE) phase diagrams have been determined, by means of the critical opalescence method with a laser scattering technique, for the mixtures 4phenylbutan-2-one + CH (CH) n CH (n = 10,12,14) and for benzyl ethanoate + CH 3 (CH 2) n CH 3 (n = 12,14). The systems are characterized by having an upper critical solution temperature (UCST), which increases with n. The corresponding LLE curves show a rather horizontal top and become skewed towards higher mole fractions of the polar compound when n is increased. Calorimetric and LLE measurements show that, for mixtures with molecules with a given functional group, interactions between aromatic molecules are stronger than those between homomorphic linear molecules (aromaticity effect). This has been ascribed to proximity effects arising from the presence of the polar group and the aromatic ring within the same molecule. Proximity effects become weaker in the sequence: 1-phenylpropan-2-one > 4-phenylbutan-2one > 1-phenylethanone, and are more important in benzyl ethanoate than in ethyl benzoate molecules. Values of the critical compositions and temperatures calculated with the DISQUAC group contribution model are in good agreement with the experimental results. Accordingly, the shape of the LLE curves is also correctly described by DISQUAC.
Journal of Chemical Thermodynamics, 2006
The extraction of aromatic compound toluene from alkane, dodecane, by mixed solvents (water + methanol), (water + ethanol) and (methanol + ethanol) have been studied by (liquid + liquid) equilibrium (LLE) measurements at three temperatures (298.15, 303.15, and 313.15) K and ambient pressure. The compositions of liquid phases at equilibrium were determined by gas liquid chromatography.The experimental tie-line data for three quaternary mixtures of {(water + methanol) + toluene + dodecane}, {(water + ethanol) + toluene + dodecane}, and {(methanol + ethanol) + toluene + dodecane} are presented. The experimental quaternary LLE data have been satisfactorily correlated by using the UNIQUAC and NRTL activity coefficient models. The parameters of the models have been evaluated and presented. The tie-line data of the studied quaternary mixtures also were correlated using the Hand method. The partition coefficients and the selectivity factor of solvent are calculated and compared for the three mixed solvents.The comparisons indicate that the selectivity factor for mixed solvent (methanol + ethanol) is higher than the other two mixed solvents at the three studied temperatures. However, considering the temperature variations of partition coefficients of toluene in two liquid phases at equilibrium, an optimum temperature may be obtained for an efficient extraction of toluene from dodecane by the mixed solvents.