Grupo Especializado en Termodinámica de los Equilibrios entre Fasesenglish versionGETEF emblema


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Año 1991

  • Cocero, MJ; Gonzalez, JA; Garcia, I; Cobos, JC; Liquid-vapor equilibrium and excess Gibbs energy of dimethyl carbonate + normal alkanes (C6, C8, C12); Int DATA Ser, Select Data Mixtures, Ser A, 19 (3) 1991 158-166
  • Cocero, MJ; Gonzalez, JA; Garcia, I; Cobos, JC; Mato, F; Liquid-vapor equilibrium and excess Gibbs energy of diethyl carbonate + normal alkanes (C6, C8, C12); Int DATA Ser, Select Data Mixtures, Ser A, 19 (2) 1991 130-138
  • Cocero, MJ; Gonzalez, JA; Garcia, I; Cobos, JC; Mato, F; Liquid-vapor equilibrium and excess Gibbs energy of dimethyl or diethyl carbonate +cyclohexane,  +benzene or +tetrachloromethane; Int DATA Ser, Select Data Mixtures, Ser A, 19 (2) 1991 112-129
  • Gonzalez, JA; de la Fuente, IG; Cobos, JC; Casanova, C;  A characterization of the aliphatic hydroxyl interactions using a group contribution model (DISQUAC); Ber Bunsen-Ges Phys Chem Chem Phys, 95 (12) 1991 1658-1668
The data available in the literature for the molar excess Gibbs energies GE, azeotropes, molar excess enthalpies HE, activity coefficients γi, and partial molar excess enthalpies HiE,∞, at infinite dilution, and molar excess heat capacities CPE, of n-alkan-1-ol (1) + n-alkane (2) mixtures are examined on the basis of the DISQUAC group contribution model. Being available the interaction parameters for systems containing methanol or ethanol, we report the interchange coefficients from propanol to hexadecanol: Cah,lDIS and Cah,lQUAC (l = 1, 2 or 3). For the dispersive coefficients: Cah,1DIS increase with the size of the n-alkan-1-ol; Cah,2DIS decrease as far as propanol, and then increase regularly; an opposite behaviour is encountered for Cah,3DIS. For the quasichemical coefficients: Cah,1QUAC and Cah,3QUAC are constant, and Cah,2QUAC varies in a similar way to the maximum of the HE of the mixtures under study; from decanol, they are constant. The model describes consistently the molar excess functions for the systems investigated, even the CPE and, qualitatively, the temperature dependence of this magnitude. Partial molar excess quantities at infinite dilution are reasonably well represented. Larger differences are obtained for HiE,∞.
  • Kehiaian, HV; Gonzalez, JA; Garcia, I; Cobos, JC; Casanova, C; Cocero, MJ; Steric and inductive effects in binary-mixtures of organic carbonates with aromatic-hydrocarbons or tetrachloromethane; Fluid Phase Equilibr, 69 1991 81-89.
Literature data on molar excess enthalpies, HE, and molar excess Gibbs energies, GE, of organic linear carbonates + aromatic hydrocarbons (benzene or toluene) or + tetrachloromethane are treated in the framework of DISQUAC, an extended group-contribution model. The mixture components are characterized by three types of groups or surfaces: carbonate (O-CO-O group), alkane (CH3 or CH2 groups), and solvent (benzene, C6H6, phenyl, C6H5, or tetrachloromethane, CCl4, groups). The alkane/solvent and alkane/carbonate interaction parameters have been estimated previously, the carbonate/solvent parameters are reported in this work. The solutions of organic carbonates in aromatic hydrocarbons or CCl4 exhibit the features of polar solute + polarizable solvent mixtures, namely, the deviations from ideality are much less positive than in n-alkanes, and may even be negative. The experimental GE and HE curves are best reproduced when the carbonate/solvent contacts are taken to be entirely dispersive. DISQUAC reproduces fairly well GE and HE as a function of concentration.
  • Kehiaian, HV; Gonzalez, JA; Garcia, I; Escarda, R; Cobos, JC; Casanova, C; Prediction of liquid-liquid equilibria and of enthalpies of mixing in alkanoic acid anhydride + normal-alkane mixtures using DISQUAC; Fluid Phase Equilibr, 69 1991 91-98
The liquid-liquid equilibrium (LLE) data from the literature on acetic anhydride + heptane and our molar excess enthalpies measured previously, HE, of butyric or heptanoic anhydrides + n-alkanes (hexane through tetradecane) are examined on the basis of the DISQUAC group-contribution model. These experimental data, along with structure-property relationships derived from the properties of related classes of carbonylic compounds, were used to estimate the interaction parameters for symmetrical or asymmetrical carboxylic acid anhydride [CH3(CH2)u-CO-O-CO-(CH2)-upsilon-CH3]+alkane [CH3(CH2)m-2CH3] mixtures. The anhydride (CO-O-CO group)/alkane (CH3 or CH2 groups) interaction parameters are the same for the anhydrides of all the carboxylic acids (u, upsilon > 1), except for acetic acid anhydride (u, upsilon = 1). The model describes consistently HE, LLE and the vapor-liquid equilibrium diagram of acetic anhydride + cyclohexane.
  • Cobos, JC; Garcia, I; Casanova, C; Roux, AH; Roux-Desgranges, G; Grolier, JPE;  Excess heat-capacities of 1-butanol + toluene from 298 K to 368 K; Fluid Phase Equilibr, 69 1991 223-233
Excess heat capacities at constant atmospheric pressure CPE of the binary system 1-butanol + toluene have been determined at 298.15 K, 323.15 K, 348.15 K and 368.15 K. The instrument used was a programmable differential scanning calorimeter based on the Calvet principle. The CPE decrease from 298.15 K to 323.15 K for mole fractions of the alcohol less than approximately 0.2, and increase for higher concentrations. From 323.15 K to 368.15 K the CPE decrease with increasing temperature. A negative region at low mole fractions of 1-butanol appears when the temperature is increased.
  • Cocero, MJ; Garcia, I; Gonzalez, JA; Cobos, JC; Thermodynamics of binary-mixtures containing organic carbonates. VI. Isothermal vapor-liquid-equilibria for dimethyl-carbonate + normal-alkanes; Fluid Phase Equilibr, 68 1991 151-161
Vapor and liquid equilibrium phase compositions were determined at 298.15 K for binary mixtures containing dimethyl carbonate and n-hexane, n-octane or n-decane. The direct experimental isothermal x-y data have been reduced to obtain the molar excess Gibbs energies GE by means of an iterative procedure similar to the Barker's method, using the Redlich-Kister equation with coefficients determined by regression through minimization of the sum of deviations in vapor-phase compositions. The data were compared on the basis of the DISQUAC group contribution model. Previously published data on vapor-liquid equilibria of dimethyl carbonate and cyclohexane, benzene or tetrachloromethane have been reduced with the same method.
  • Gonzalez, JA; Garcia, I; Gonzalez, JA; Cobos, JC; Casanova, C; Predictions of excess-enthalpies of some ternary-systems involving a binary mixture with a mixcibility gap using a group contribution model; Thermochim Acta, 189 (1) 1991 115-127
A new study has been made of the performance of the Kehiaian-Guggenheim-Barker group contribution model in the characterization of the excess molar enthalpies (HE) of ternary organic mixtures. The present work reports the predictions of the model for seven sets of HE ternary data. The seven mixtures of methanol, as first component, with n-alkanes and aromatic hydrocarbons were treated in the framework of the DISQUAC model. The ratios of the standard deviations between experimental and predicted excess molar enthalpies and the maximum value of this excess function are less than 0.38 for all the systems. Previously obtained parameters for alcohol-aliphatic and alcohol-aromatic interactions were tested with the binary excess functions HE, GE and excess heat capacity CPE, liquid-liquid equilibria, and activity coefficients at infinite dilution.
  • Kehiaian, HV; Gonzalez, JA; Garcia, I; Cobos, JC; Casanova, C; Cocero, MJ;  Prediction of vapor-liquid and liquid-liquid equilibria and of enthalpies of mixing in linear carbonates +n-alkane or +cyclohexane mixtures using DISQUAC; Fluid Phase Equilibr, 64 1991 1-11
Previously measured data on phase equilibria (vapour-liquid and liquid-liquid) and enthalpies of mixing of dimethyl carbonate or diethyl carbonate +n-alkanes or +cyclohexane were examined on the basis of the DISQUAC group contribution model. The interaction parameters for the carbonate/alkane and carbonate/cyclohexane contacts are reported. The dispersive parameters are the same for the two carbonates but are slightly larger for cyclohexane, compared to n-alkanes. The quasichemical parameters are the same for n-alkanes and cyclohexane, but are smaller for diethyl carbonate compared to dimethyl carbonate (steric effect). The parameters of the other di-n-alkyl carbonates were estimated. The model provides a fairly consistent description of phase equilibria and enthalpies of mixing using the same set of parameters.
  • Gonzalez, JA; Garcia, I; Cobos, JC; Casanova, C;  Thermodynamics of binary-mixtures containing organic carbonates. IV. Liquid-liquid equilibria of dimethyl-carbonate + selected n-alkanes; J Chem Eng Data, 36 (2) 1991 162-164
Liquid-liquid equilibrium (LLE) data are reported for dimethyl carbonate +n-decane, +n-dodecane, +n-tetradecane or +n-hexadecane at atmospheric pressure, between 277 K and the upper critical temperatures. The solubility curve of pure solid n-hexadecane in liquid dimethyl carbonate is also presented. The coexistence curves are very asymmetrical with respect to mole fraction, the asymmetry increasing with the size of the n-alkane. The critical solution points vary almost linearly with the number of carbon atoms of the n-alkane. The data are used in the framework of regular solution theory to obtain the solubility parameter of dimethyl carbonate.



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