B. E. de Cominges

Derived Properties of Binary Mixtures Containing (Acetone or Methanol) + Hydroxil Compounds

Abstract This work reports values of the density, refractive index and speed of sound of the binary mixtures acetone or methanol with (2-methyl, 1-propanol, 3-methyl, 1-butanol, 1,2-ethanediol, 1,2-propanediol and 1,3-propanediol) at 298.15 K and atmosphere, as a function of the mole fraction. From the experimental values, the corresponding excess and derived magnitudes were computed (excess molar volumes, changes of refractive index on mixing and changes of isentropic compressibility on mixing), variable-degree polynomials being fitted to the results. Only expansive trend was observed for those mixtures enclosing branched alcohols. The influence of the hydroxil group in the nonideal behaviour of these mixtures were analyzed in terms of the partial molar excess volumes.

Estimation of parameters of Nitta–Chao model for ester+1-alkanol mixtures

Abstract An updated database with experimental values on vapor–liquid equilibria, activity coefficient at infinite dilution, enthalpies of mixing and excess molar volumes of alkyl alkanoate+1-alkanol binary systems was used to redetermine structure and interaction parameters of the Nitta–Chao model. We have compared the theoretical results obtained with the Nitta–Chao model and our parameters with the experimental data. The percentual mean deviations with the parameters calculated in this work are quite good for all properties studied. We have used the same database to analyse the quality of the predictions of three versions of UNIFAC model for this type of mixtures.

Temperature dependence of thermophysical properties of octane+1-butanol system

The aim of this work is to complete our studies on physical properties of binary mixtures of alkane+1-alkanols. This work reports densities, refractive indices, speeds of sound and isentropic compressibilities of the mixture octane + 1-butanol at different temperatures, from 288.15 to 308.15 K. From the experimental values, the corresponding excess and deviation values were computed (excess molar volumes, changes of refractive index on mixing, changes of speed of sound on mixing and changes of isentropic compressibilities on mixing). The results were fitted to variable-degree polynomials. Excess molar volumes were compared with the predictions of Nitta-Chao Group Contribution Model.

Relative permittivities of binary mixtures of 1-butanol + n-alkane AT 298.15 k

A previous study on the physical properties of 1-alkanol + n-alkane has establised a correlation between dielectric permittivity at 1 GHz and excess molar volumes for all binary systems that were studied. In order to determine whether this behaviour is similar at lower frequencies, relative permittivity was measured at 100 kHz. The refractive index was measured to explore the effects at higher frequencies. Mixtures under study are in particular the systems (1-butanol + n-hexane, or n-octane, or n-decane) at the temperature of 298.15 K and atmospheric pressure, over the entire composition range.

Excess permittivity behaviour of some mixtures n-alcohol + alkane : an interpretation of the underlying molecular mechanism

A molecular mechanism is proposed that underlies the macroscopic behaviour of excess dielectric permittivity of some mixtures {n-alcohol + alkane} at low (100 kHz) and microwave frequencies (1 GHz). This behaviour has been determined experimentally at 298 K, as a function of molar fraction, for the mixtures {n-hexane + (pentan-1-ol, hexan-1-ol or heptan-1-ol)} and {cyclohexane + (pentan-1-ol, hexan-1-ol or heptan-1-ol)}. From the magnitudes inherent to the process of dielectric relaxation the results obtained have been explained in terms of the behaviour of thermodynamic magnitudes such as the excess molar enthalpy and the excess molar volume, as well as the consideration that the total dipole moment of a multimere is greater than the sum of all dipole moments of the monomeres in which it can be decomposed (when hydrogen bonds are broken), in agreement with the linear association model of Malecki (LAM). Measurements of the relaxation times for the mixtures under study at various molar fractions using time-domain reflectometry (TDR) (DC–5 GHz) at ambient temperature confirm the considerations that support the proposed interpretation.

Temperature dependence of volumetric behaviour for methyl tert-butylether+1-butanol system

Excess molar volumes and excess isoentropic compressibilities of methyl tert-butylether (MTBE)+1-butanol at 288.15, 293.15, 298.15, 303.15 and 308.15 K and atmospheric pressure have been studied. In order to analyse the temperature dependence of this mixture, isobaric expansibility a, (dVme dT)P,xand (dHme dP)T,x, were computed by analytical differentiation of the density and excess molar volume fitting equations. Cubic equation of state (Soave-Redlich-Kwong) has been applied to excess molar volume correlation obtaining binary interaction parameters using different mixing rules.

Application of Different Group Contribution Models and Empirical Methods to Excess Enthalpies of Ternary Mixtures

Studies were previously made of the excess molar enthalpies, HmE, at 298.15 K and normal atmospheric pressure of the ternary mixtures (ethyl propanoate or 3-pentanone) + (n-hexane) + (n-decane, n-dodecane or n-tetradecane) and (1-propanol) + (3-pentanone) + (n-hexane, n-heptane, n-octane, 1-hexanol or 1-heptanol). In the present work, experimental values of HmE were correlated through use of the Cibulka and Nagata equations, and a new correlation equation is proposed. Experimental data were compared with the predictions of the UNIFAC I (version of Tassios), UNIFAC II (version of Larsen) and Nitta-Chao group contribution models. HmE values were used to test several empirical predictive methods, both symmetric (Kohler, Jacob-Fitzner, Colinet and Knobeloch-Schwartz), and asymmetric (Tsao-Smith, Toop, Scatchard, Hillert and Mathieson-Tynne).

Excess molar volume of dimethyl carbonate +p-xylene + n-decane at 288.15 and 298.15 k

Densities for dimethyl carbonate + p-xylene + n-decane ternary system, at 288.15 and 298.15 K and at atmospheric pressure, were measured. The corresponding excess molar volumes were calculated from the experimental data and were fitted by means of Cibulka equation.

Temperature dependence of the refractive index for the mixtures {CH3(CH2)xOH, x=1, 2}+ {(CH3)2CH(CH2)yOH, y=0, 1, 2} and estimation by means of cubic equations of state

The applicability of cubic equations of state for refractive index estimation for binary alcohol mixtures {CH3(CH2)xOH, x=1, 2}+{(CH3)2CH(CH2)yOH, y=0, 1, 2} at different temperatures was evaluated by using a derivation of the Heller equation. A qualitatively accurate response was obtained from the cubic equations and mixing rules applied, and the binary parameter obtained can be used for multicomponent refractive index prediction, or even for other thermodynamic properties.

Analysis of the interaction between cycloalkanes and 1-alkanols by means of Nitta Chao group contribution model

Abstract The interaction between cyclic alkane (CH 2 r ) and hydroxyl (OH) structural groups was revised within the framework of Nitta Chao group contribution model. New interaction parameters were calculated using an updated database, and previous results were clearly improved. Comparison was established with other group contribution models (UNIFAC, DISQUAC).