Principal Miembros Historia Investigación Laboratorio Publicaciones Proyectos Enlaces

Año 1998

- Rubio, MA; Gonzalez, JA; de la Fuente, IG; Cobos, JC;
Thermodynamic properties of n-alkoxyethanols
plus organic solvents
mixtures - VIII. Liquid-liquid equilibria of systems containing
2-methoxyethanol and alkanes (C
_{6}H_{12}and CH_{3}-(CH_{2})_{u}-CH_{3}, u=3, 4, 6, 8); Fluid Phase Equilibr, 143 (1-2) 1998 111-123

Liquid-liquid equilibria (LLE) data are
reported for 2-methoxyethanol + n-pentane,
+ n-hexane, + n-octane, + n-decane, or + cyclohexane mixtures
at atmospheric pressure, between
281 K and the upper critical solutions temperatures (UCST). The
coexistence curves were determined visually. These curves are rather
symmetrical, with the asymmetry increasing with the size of the n-alkane. The UCSTs increase almost
linearly with the number of the
carbon atoms of the n-alkane.
The system with cyclohexane shows the
lower UCST. The (x,T) data were fitted to the equation
T = T_{c}
+
k_{c}^{m} where y = γ x_{1}/{1
+ x_{1}(γ - 1)} and y_{c}
=
γ x_{1c}/{1 + x_{1c}(γ - 1)}. T_{c} and x_{1c}
are the coordinates
of the critical points fitted together with k, m and γ using a
Marquardt algorithm. The critical exponents of the order parameter for
the mixtures studied are calculated. Its mean value is 0.363.

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- Domanska, U; Gonzalez, JA; Thermodynamics of branched alcohols - II. Solid-liquid equilibria for systems containing tert-butanol and long-chain n-alkanes. Experimental results and comparison with DISQUAC predictions; Fluid Phase Equilibr, 147 (1-2) 1997 251-270

Solid-liquid equilibrium temperatures
for tert-butanol + n-alkanes
(C_{18}, C_{19}, C_{20},
C_{21}, C_{22}, C_{23}, C_{24},
C_{25}, C_{26}, C_{28}) systems have been
measured by a dynamic method from
298.15 K to the melting point of the alkane. All the systems present an
eutectic point at very low concentration of the alcohol. A first-order
transition was observed for many of the n-alkanes considered. The
experimental values are compared with those given by the DISQUAC model
using the interaction parameters previously determined on the basis of
vapor-liquid equilibria, VLE, and molar excess enthalpies, H^{E}, of
systems containing the lower n-alkanes
(n-C-6, n-C-7). Calculations
were developed taking into account the solid-solid transition of the
alkanes. The mean relative standard deviation for the equilibrium
temperatures is 0.0073. Differences between experimental data and
calculated results for SLE and H^{E}
are analysed in terms of
the
Patterson effect. The possibility of improving predictions by modifying
only the third dispersive interchange coefficient is discussed. Two
values for this parameter are proposed depending on n, hereafter the
number of C atoms in the n-alkane
(n less than or equal to 8 and n
greater than or equal to 9). In this way, the variation with the
temperature of H^{E}
is better represented by the model for
those systems
including the longer n-alkanes.
Predictions on SLE remain unchanged,
because they depend essentially on the first interchange coefficients
when the range of temperature considered, as in this case, is rather
narrow.

- Rubio, MA; Gonzalez, JA; de la Fuente, IG; Cobos, JC; Thermodynamic properties of n-alkoxyethanols plus organic solvent mixtures. IX. Liquid-liquid equilibria of systems containing 2-methoxyethanol or 2-ethoxyethanol and selected n-alkanes; J Chem Eng Data, 43 (5) 1998 811-814

Liquid-liquid equilibria (LLE) data are
reported for 2-methoxyethanol + dodecane, and for 8-ethoxyethanol +
dodecane, + tetradecane, or + hexadecane mixtures between 275.7 K and
the upper critical solution temperatures (UCST). The solubility curve
of pure solid hexadecane in liquid 2-ethoxyethanol is also presented in
the range of 0 to 0.1833 of mole fraction in 2-ethoxyethanol. The
coexistence curves were determined visually. For a given alkoxyethanol,
the LLE curves are rather asymmetrical, with the asymmetry increasing
with the size of the n-alkane.
Moreover, the UCSTs increase almost
linearly with the number of the carbon atoms of the n-alkane. The (x,
T) data were fitted to the
equation T = T_{c} +
k_{c}^{m} where y = γ x_{1}/[1
+ x_{1}(γ - 1)] and y_{c}
=
γ x_{1c}/[1 + x_{1c}(γ - 1)].
T_{c} and x_{1c} are the coordinates of the critical
points fitted together
with k, m, and alpha using a Marquardt algorithm.

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Principal Miembros Historia Investigación Laboratorio Publicaciones Proyectos Enlaces