Isaias Garcia

Excess properties of mixtures of some n-alkoxyethanols with organic solvents: III. VE and CEp with butan-1-ol at 298.15 K

The excess molar volumes, VE, and the excess molar heat capacities, CEp are determined as a function of mole fraction, X, at atmospheric pressure and 298.15 K for 2-methoxyethanol (1), 2-ethoxyethanol (1), 2-butoxyethanol (1), 2-(2-methoxyethoxy)ethanol (1), 2-(2-ethoxyethoxy)ethanol (1), 2-(2-butoxyethoxy)ethanol (1) with butan-1-ol (2) mixtures. The VE values decrease in magnitude as the alkyl chain length of the n-alkoxyethanol increases for the two homologous series; they are positive except for the mixtures containing 2-butoxy-ethanol and 2-(2-butoxyethoxy)ethanol for which they are negative over the whole mole-fraction range. The CEp values are positive and relatively small for all the mixtures studied.

Thermodynamics of binary mixtures containing organic carbonates: Part VI. Isothermal vapor-liquid equilibria for dimethyl carbonate + normal alkanes

Abstract Cocero, M.J., Garcia, I., Gonzalez, J.A. and Cobos, J.C., 1991. Thermodynamics of binary mixtures containing organic carbonates. Part VI. Isothermal vapor-liquid equilibria for dimethyl carbonate + normal alkanes. Fluid Phase Equilibria , 68: 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 G E by means of an iterative procedure similar to the Barkers 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.

Prediction of excess functions of some ternary organic mixtures containing ethanol with a group contribution model

Abstract A study has been made of the performance of the Kehiaian-Guggenheim-Barker group contribution model in the characterization of the excess molar functions of ternary organic mixtures. The present work reports the predictions of the model for the concentration dependence of one set of G E ternary data and eight sets of H E ternary data. The nine mixtures, of ethanol, as first component, with n -alkanes, cyclohexane 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 H E or excess molar Gibbs functions G E and the maximum values of those excess functions are less than 0.11 for all the systems. Previously obtained parameters for alcohol-aliphatic, alcohol-aromatic and alcohol-cyclic interactions were tested with the binary excess functions H E , G E and the excess heat capacity C E p , liquid-liquid equilibria and activity coefficients at infinite dilution.

Prediction of vapour—liquid and liquid—liquid equilibria and of enthalpies of mixing in linear carbonates + n-alkane or + cyclohexane mixtures using DISQUAC

Abstract 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.

Excess enthalpies of (3,6,9-trioxaundecane + an n-alkan-1-ol) at 298.15 K

Abstract The excess molar enthalpy H m E has been determined as a function of mole fraction x at atmospheric pressure and 298.15 K for five { x (CH 3 CH 2 OCH 2 CH 2 ) 2 O + (1 − x ) n -C ν H 2 ν +1 OH} mixtures (ν = 3, 4, 5, 7, and 9). All the mixtures show positive and nearly symmetrical excess molar enthalpies which increase with increasing chain length ν of the alkanol.

Excess properties of mixtures of some n-alkoxyethanols with organic solvents: IV. HE, VE and CEP with 2-methoxyethanol at 298.15 K1

Abstract Molar excess enthalpies H E , molar excess volumes V E and molar excess heat capacities C E p of mixtures of 2-methoxyethanol (1) with 2-ethoxyethanol (2), 2-butoxyethanol (2) and 2-(2-methoxyethoxy)ethanol (2) and H E of mixtures of 2-methoxyethanol (1) with 2-(2-ethoxyethoxy) ethanol (2) and 2-(2-butoxyethoxy)ethanol (2) were determined as a function of composition at 298.15 K and atmospheric pressure. As expected, owing to the similar chemical nature of the components, the excess functions of these mixtures are relatively small.

Prediction of liquid-liquid equilibria and of enthalpies of mixing in alkanoic acid anhydride + n-alkane mixtures using DISQUAC☆

Abstract Kehiaian, H.V., Gonzalez, J.A., Garcia, I., Escarda, R., Cobos, J.C. and Casanova, C, 1991. Prediction of liquid-liquid equilibria and of enthalpies of mixing in alkanoic acid anhydride + n -alkane mixtures using DISQUAC. Fluid Phase Equilibria, 69: 91-98. The liquid-liquid equilibrium (LLE) data from the literature on acetic anhydride + heptane and our molar excess enthalpies measured previously, H E , 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 [CH 3 (CH 2 ) u -1 -CO-O-CO-(CH 2 )[ v -1 CH 3 ] + alkane [CH 3 (CH 2 ) m -2 CH 3 ] mixtures. The anhydride (CO-O-CO group)/alkane (CH 3 or CH 2 groups) interaction parameters are the same for the anhydrides of all the carboxylic acids ( u, v > 1), except for acetic acid anhydride ( u, v = 1). The model describes consistently H E , LLE and the vapor-liquid equilibrium diagram of acetic anhydride + cyclohexane.

Excess heat capacities of 1-butanol + toluene from 298 to 368 K

Abstract Cobos, J.C., Garcia, I., Casanova, C., Roux, A.H., Roux-Desgranges, G. and Grolier, J.-P.E., 1991. Excess heat capacities of 1-butanol + toluene from 298 to 368 K. Fluid Phase Equilibria, 69: 223-233. Excess heat capacities at constant atmospheric pressure CEP 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 CEP decrease from 298.15 K to 323.15 K for mole fractions of the alcohol less than ~ 0.2, and increase for higher concentrations. From 323.15 K to 368.15 K the CEP decrease with increasing temperature. A negative region at low mole fractions of 1-butanol appears when the temperature is increased.

Steric and inductive effects in binary mixtures of organic carbonates with aromatic hydrocarbons or tetrachloromethane

Abstract Kehiaian H.V., Gonzalez J.A., Garcia I., Cobos J.C., Casanova C. and Cocero M.J., 1991. Steric and inductive effects in binary mixtures of organic carbonates with aromatic hydrocarbons or tetrachloromethane. Fluid Phase Equilibria , 69: 81-89. Literature data on molar excess enthalpies, H E , and molar excess Gibbs energies, G E , 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 (CH 3 or CH 2 groups), and solvent (benzene, C 6 H 6 , phenyl, C 6 H 5 , or tetrachloromethane, CCl 4 , 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 CCl 4 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 G E and H E curves are best reproduced when the carbonate/solvent contacts are taken to be entirely dispersive. DISQUAC reproduces fairly well G E and H E as a function of concentration.

Prediction of excess enthalpies of some ternary systems involving a binary mixture with a miscibility gap using a group contribution model

Abstract 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 ( H E ) of ternary organic mixtures. The present work reports the predictions of the model for seven sets of H E 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 H E , G E and excess heat capacity C p E , liquid-liquid equilibria, and activity coefficients at infinite dilution.