Investigation on molecular interactions of binary mixtures of
isobutanol with 1-alkanols (C
1
e C
6
) at different temperatures.
Application of the PengeRobinsoneStryjekeVera (PSRV) equation of
state (EOS)
K. Khanlarzadeh, H. Iloukhani
*
, M. Soleimani
Department of Physical Chemistry, Faculty of Chemistry, Bu-Ali Sina University, Hamedan, Iran
article info
Article history:
Received 17 January 2017
Received in revised form
3 March 2017
Accepted 6 March 2017
Keywords:
Excess molar volumes
Isobutanol
1-Alkanols
RedlichKister
PSRV equation of state
abstract
Densities were measured for binary mixtures of isobutanol with 1-alkanols, namely: methanol, ethanol,
1-propanol, 1-butanol, 1-pentanol and 1-hexanol at the temperatures of (288.15, 298.15 and 308.15) K
and ambient pressure. Excess molar volumes, V
E
m
, thermal expansion coefficients a, excess thermal
expansion coefficients a
E
, and isothermal coefficients of pressure excess molar enthalpy, ðvH
E
m
=vPÞ
T;x
,
were derived from the experimental data and the computed results were fitted to the RedlicheKister
equation. The PengeRobinsoneStryjekeVera (PRSV) equation of state was applied, in combination with
simple mixing rules to predict the excess molar volume. The V
E
m
results were positive for the mixtures of
isobutanol with methanol, ethanol, 1-propanol, 1-butanol, and negative for isobutanol with 1-pentanol
and 1-hexanol over the whole composition range. The results showed very small deviations from the
behavior of ideal solutions in these mixtures and were analyzed to discuss the nature and strength of
intermolecular interactions.
© 2017 Published by Elsevier B.V.
1. Introduction
Binary mixtures consisting of two alcohols seem to be rather
interesting because of very small deviations from the behavior of
ideal solutions. In the last decade, investigations dealing with
mixture properties of this kind have been rather rarely reported
[1e6]. The behavior of systems consisting of compounds able to
create hydrogen bonding in the pure state as well as in mixtures
with another active component is easy to explain. It is well-known
that during mixing, the original hydrogen bonds existing in the
pure components become partially broken and simultaneously
those bonds are formed between molecules of different kinds.
These two effects have opposite contributions to all the excess
molar quantities. Besides, a very important role plays non-specific
interactions an occurrence which is usually underestimated in
mixtures of two alcohols. In recent years there has been consider-
able advancement in the experimental investigation of the excess
thermodynamic properties (excess molar volumes, partial excess
and partial molar volumes, phase equilibrium, excess molar en-
thalpies, etc.). These factors have been increased in study due to
their simplicity as models, having low data requirements and
versatility in operational conditions. This paper is a continuation of
our earlier work related to the study of thermodynamic and
transport properties of binary mixtures [7e10]. Our research group
purpose of the preceding papers of this series was to provide a set
of thermodynamic data for the analysis and characterization of
molecular interactions in organic solvents at different tempera-
tures. In continuation with these investigations the present paper
reports the excess molar volumes V
E
m
, thermal expansion co-
efficients a, excess thermal expansion coefficients a
E
, and
isothermal coefficients of pressure excess molar enthalpy,
ðvH
E
m
=vPÞ
T ;x
, for the binary systems of isobutanol þ (methanol,
ethanol, 1-propanol, 1-butanol, 1-pentanol and 1-hexanol). Excess
thermodynamic properties have also been used as a qualitative and
quantitative guide to predict the extent of complex formation in
this kind of mixtures [11e 13]. Knowledge of several properties at
different temperatures is required for engineering design and for
subsequent operations [14].
The equations of state (EOS
0
) are the simplest way for devel-
oping of fluid state theories as well as in modeling fluid behavior for
* Corresponding author.
E-mail address: iloukhani@basu.ac.ir (H. Iloukhani).
Contents lists available at ScienceDirect
Journal of Molecular Structure
journal homepage: http://www.elsevier.com/locate/molstruc
http://dx.doi.org/10.1016/j.molstruc.2017.03.023
0022-2860/© 2017 Published by Elsevier B.V.
Journal of Molecular Structure 1139 (2017) 78e86