- Domanska, U; Gonzalez, JA; Solid-liquid equilibria for
systems containing long-chain 1-alkanols. I. Experimental data for
1-dodecanol, 1-tetradecanol, 1-hexadecanol, 1-octadecanol or
1-icosanol-benzene or -toluene mixtures. Characterization in terms of
DISQUAC; Fluid Phase Equilibr,
119 (1-2) 1996 131-151
Solid-liquid equilibrium temperatures
for binary mixtures of long-chain 1-alkanols (1-dodecanol,
1-tetradecanol, 1-hexadecanol, 1-octadecanol and 1-icosanol) and
benzene or toluene have been measured by a dynamic method between 276 K
and the melting point of the alcohol. These data are used, taking into
consideration the two solid-solid first-order transitions observed in
the 1-alkanols, to characterize in terms of DISQUAC the
hydroxyl-aromatic interactions present in the investigated mixtures.
The relative standard deviations for the equilibrium temperatures are
less than 0.01 for most of the systems.
- Gonzalez, JA; de la Fuente, IG; Cobos, JC; Domanska, U;
Thermodynamics of branched alcohols. I. Extension of DISQUAC to
tert-alcohols-n-alkanes or
tert-alcohols-cyclohexane mixtures; Fluid
Phase Equilibr, 119 (1-2) 1996
81-96.
DISQUAC interchange coefficients for
the contacts tertiary OH-aliphatic and tertiary OH-cyclohexane are
reported. The quasichemical parameters are independent of the alkane;
the first and third quasichemical parameters are common for the
alkanols investigated, whereas the second depends on the position of
the OH group. Therefore, two ensembles of alcohols are distinguished:
2-methyl-2-alkanols and 3-methyl-3-alkanols. Tert-butanol behaves
differently owing to its high melting point. Dispersive parameters
change with the alcohol. This behaviour is compared with that observed
for other contacts. Vapor-liquid equilibria and excess functions, even
the excess heat capacity, are well represented by the model. In
contrast, partial molar excess quantities at infinite dilution are
poorly described.
- Gonzalez, JA; de la Fuente, IG; Cobos, JC; DISQUAC analysis
of
binary liquid organic mixtures containing cyclic or linear alkanols and
cycloalkanes or n-alkanes; Thermochima
Acta, 278 1996 57-69
Literature data for cycloalkanol +
cycloalkane or n-alkane
mixtures are critically reviewed and
characterized in terms of the DISQUAC model incorporating
intramolecular effects related to the inclusion of a functional group,
OH, in an aliphatic ring.
Although the interaction parameters follow similar rules to those
encountered for other heterocycles (amines, ethers, ketones), some
differences are found, e.g., the quasichemical coefficients are
independent not only (as usual) of the alkane, but also of the
cycloalkanol.
It is shown that for such systems steric effects are less important
than ring strain.
A treatment of 1-alkanols + cycloalkanes (except C6H12)
mixtures using the interaction parameters determined previously for
cyclohexane is included.
- Domanska, U; Gonzalez, JA; Solid-liquid equilibria for
systems
containing long-chain 1-alkanols. II. Experimental data for
1-dodecanol,
1-tetradecanol, 1-hexadecanol, 1-octadecanol or 1-eicosanol plus CCl4
or plus cyclohexane mixtures. Characterization in terms of DISQUAC; Fluid Phase Equilibr, 123
(1-2) 1996
167-187
Solid-liquid equilibrium (SLE)
temperatures for 1-dodecanol, 1-tetradecanol, 1-hexadecanol,
1-octadecanol or 1-eicosanol + CCl4 mixtures and for
1-dodecanol or 1-tetradecanol + cyclohexane systems have been measured
by a dynamic method between 273 K to the melting point of the alcohol.
First order transitions between different crystal forms (α, β,
γ) of the alcohols were observed, The solid-solid transitions of
these long-chain alcohols changed with the solvent as result of
solute-solvent interactions. This behaviour is also encountered in many
other systems. The hydroxyl/cyclohexane and hydroxyl/CCl4
interactions present in the investigated systems were characterized in
terms of DISQUAC, reporting the interchange coefficients for such
contacts. It is remarkable that these interchange coefficients remain
constant for a given alcohol: from 1-octadecanol for mixtures with
cyclohexane, and from 1-hexadecanol for those systems containing CCl4.
Calculations were developed taking into account the solid-solid
transitions of the 1-alkanols. This is important because of the large
value of the molar heat of the α → β transition. For
mixtures containing alcohols other than 1-eicosanol the relative
standard deviations for the equilibrium temperatures were less than
0.009. For mixtures containing 1-eicosanol the relative standard
deviations were close to 0.020, because the model cannot, using the
proposed interaction parameters, reproduce their negative deviations
from Raoult's law.
- Gonzalez, JA; de la Fuente, IG; Cobos, JC; Estimation of
DISQUAC
interchange energy parameters for linear secondary alcohols plus n-alkanes or plus
cyclohexane mixtures; Fluid Phase
Equilibr, 123 (1-2) 1996
39-57
The data available in die literature on
vapor-liquid equilibria (VLE), molar excess Gibbs energies (GE),
molar enthalpies (HE),
molar excess heat capacities (CPE),
activity coefficients (γi∞) and partial molar
excess
enthalpies (HiE,∞)
at infinite dilution of
linear secondary alkanols (1) + n-alkanes
(2) or + cyclohexane (2)
systems are examined on the basis of the DISQUAC group contribution
model.
The components in the mixtures are characterized by three types of
groups of surfaces: hydroxyl (OH group); aliphatic (CH3, CH2
and CH
groups); and cyclohexane(c-CH2 group). The purely dispersive
parameters of the aliphatic/cyclohexane contacts are available in the
literature. The parameters for the secondary OH/aliphatic and secondary
OH/cyclohexane interactions are reported in this work. The
quasi-chemical parameters are independent of the alkane. The first and
third parameters are common for the alkanols investigated. The second
quasi-chemical parameter depends on the position of the OH group. So,
on the basis of available data, two groups of alcohols are
distinguished: 2-alkanols and 3-alkanols. The dispersive parameters
change with the alcohol.
The model describes consistently the phase equilibria and molar excess
functions. Dependence on temperature of CPE
is
well represented,
except at very low temperatures. The absolute mean deviation for γi∞
is about 6.6%, For i = 1, the deviation is 9.2%; for
i = 2, it is 3.9%, DISQUAC cannot represent HiE,∞,
i.e. the
calculated HE
curves vs. x1, the
mole fraction,
are not as steep as
the experimental ones at very high dilution of the alcohol. This may be
considered the major limitation of the model.
So, in terms of DISQUAC, the investigated mixtures behave similarly to
1-alkanol (1) + alkane (2) systems.
- Gonzalez, JA; Martinez, JMF; de la Fuente, IG; Cobos, JC;
DISQUAC
characterization of the carbonyl-oxygen interactions in binary liquid
organic mixtures containing linear molecules: Ketones and a monoether,
diether, or triether; Can J Chem-Rev Can Chim, 74 (10) 1996 1815-1823
The available data in the literature on
vapor-liquid equilibria, excess Gibbs energies, and excess enthalpies
for linear ketones + linear mono- or poly-ether mixtures are examined
in terms of the DISQUAC group contribution model. Interaction
parameters are reported. The quasichemical interchange coefficients are
independent of the compounds in the systems; the dispersive interchange
coefficients depend on the intramolecular environment of the carbonyl
and (or) oxygen groups. Proximity effects, which seem to lead to an
important increase of the interaction parameters, are briefly
considered in treating systems including 1-methoxy-2-propanone or
dimethyl carbonate molecules. DISQUAC consistently describes the
experimental data of the mixtures investigated. The rather good
representation obtained for vapor-liquid equilibria at high
temperatures is noteworthy. A discussion in terms of effective and
reduced dipole moments of binary mixtures containing carbonyl and
oxygen groups in the same or different molecules is also presented.
- Gonzalez, JA; de la Fuente, IG; Cobos, JC; Application of a
purely physical model (DISQUAC) to binary mixtures of phenol and
organic solvents; Ber Bunsen-Ges
Phys Chem Chem Phys, 100 (10) 1996
1746-1751
A whole set of literature data on phase
equilibria, vapor-liquid equilibria, VLE, liquid-liquid equilibria,
LLE, and solid-liquid equilibria, SLE, and on molar excess Gibbs
energies, GE,
molar excess enthalpies, HE
and on
activity
coefficients at infinite dilution for phenol + organic solvents
mixtures are examined in terms of the DISQUAC group contribution model.
The interchange coefficients for OH(phenol)/aromatic;
OH(phenol)/aliphatic and for OH(phenol)/C6H12
interactions are reported.
DISQUAC yields a good representation of VLE, GE and HE,
as well as
of the temperature dependence of GE.
DISQUAC predictions on
SLE are
similar to those encountered in other alcoholic solutions previously
investigated, and are slightly worse than those given by the mean
association number theory. LLE data are critically reviewed. The
necessity of different third interchange coefficients for the
OH(phenol)/aliphatic interactions in the series phenol + n-alkanes for
the longer n-alkanes in order
to improve LLE predictions is discussed.
The larger discrepancies are found when predicting activity
coefficients at infinite dilution.