Thermodynamic Characterization of Surface and Solubility of 5-((S)-3,7-Dimethyloctyloxy)-2-[[[4-(octyloxy)phenyl]imino]methyl]phenol Liquid Crystal with Some Solvents

Article abstract of DOI:10.1021/acs.jced.8b00903

The inverse gas chromatography method was used to obtain dispersive surface energy, surface acidity or basicity constants, mole fraction activity coefficients of the solvents at infinite dilution for a new salicylaldimine based chiral calamitic liquid crystal 5-((S)-3,7-dimethyloctyloxy)-2-[[[4-(octyloxy)phenyl]imino]methyl]phenol (DOPIMP). The dispersive surface energy of DOPIMP was estimated as 41.1 mJ/m² at 30 °C and decreased with temperature. The specific free energy, enthalpy, and entropy of adsorption of the selected polar solvents on the liquid crystal were determined. The values of adsorption enthalpy were correlated with both donor and acceptor numbers of the solvents to quantify acidic K_A and basic K_D parameters of the liquid crystal surface. The results indicated that the surface of DOPIMP is basic. The retention diagrams of n-hexane, n-heptane, n-octane, n-nonane, n-decane, undecane, ethyl acetate, n-butyl acetate, iso-butyl acetate, toluene, ethylbenzene, n-propylbenzene, and chlorobenzene on the DOPIMP were plotted as straight lines using the net retention volumes at temperatures between 368.2 and 398.2 K. The values of activity coefficients indicated that DOPIMP was better soluble in long chain alkanes. Negatively signed partial molar Gibbs energies of mixing were obtained at infinite dilution of studied solvents.

Full text of DOI:10.1021/acs.jced.8b00903

Article
Cite This: J. Chem. Eng. Data XXXX, XXX, XXX−XXX
pubs.acs.org/jced
Thermodynamic Characterization of Surface and Solubility of
‑((S)‑3,7-Dimethyloctyloxy)-2-[[[4-
octyloxy)phenyl]imino]methyl]phenol Liquid Crystal with Some
Solvents
5
(
1
2
2
2
,2
Serap Mutlu Yanic, Fatih Cakar, Hale Ocak, Ferdane Karaman, Ozlem Cankurtaran,*
2
and Belkız Bilgin Eran
1
Chemistry Technology Programme, Istanbul Gedik University, Pendik Campus, 34906, Istanbul, Turkey
2
Department of Chemistry, Yildiz Technical University, Davutpasa Campus, 34220, Istanbul, Turkey
*
S Supporting Information
ABSTRACT: The inverse gas chromatography method was used to
obtain dispersive surface energy, surface acidity or basicity constants,
mole fraction activity coefficients of the solvents at infinite dilution for a
new salicylaldimine based chiral calamitic liquid crystal 5-((S)-3,7-
dimethyloctyloxy)-2-[[[4-(octyloxy)phenyl]imino]methyl]phenol
(
4
DOPIMP). The dispersive surface energy of DOPIMP was estimated as
1.1 mJ/m at 30 °C and decreased with temperature. The specific free
2
energy, enthalpy, and entropy of adsorption of the selected polar solvents
on the liquid crystal were determined. The values of adsorption enthalpy
were correlated with both donor and acceptor numbers of the solvents to
quantify acidic K and basic K parameters of the liquid crystal surface.
A
D
The results indicated that the surface of DOPIMP is basic. The retention
diagrams of n-hexane, n-heptane, n-octane, n-nonane, n-decane,
undecane, ethyl acetate, n-butyl acetate, iso-butyl acetate, toluene, ethylbenzene, n-propylbenzene, and chlorobenzene on the
DOPIMP were plotted as straight lines using the net retention volumes at temperatures between 368.2 and 398.2 K. The values
of activity coefficients indicated that DOPIMP was better soluble in long chain alkanes. Negatively signed partial molar Gibbs
energies of mixing were obtained at infinite dilution of studied solvents.
1
. INTRODUCTION
One of the major aims in the design of LC materials is to
understand the molecular interactions induced in the LC
mesophases for developing suitable new applications. Salicy-
laldimine LCs are sufficiently sensitive to various external
effects such as temperature, electric and magnetic fields, and
Liquid crystals (LCs) which exhibit a combination of fluidity
and long-range order are a fascinating class of soft materials
with high technological importance. These ordered soft
materials are used in a wide variety of fields of advanced
technologies such as electron, ion, molecular transporting,
sensing, catalysis, as well as primarily LC display devices.
The mesogenic materials based on rodlike anisometric units
show helical superstructures such as chiral smectics by
introduction of chirality. On the other hand, salicylimine
linking groups are very useful to provide stability on
mesomorphic properties due to intramolecular hydrogen
1
,2
9
deformation of surfaces. Also, the synthetic ease and self-
2
,3
organizing abilities of salicylaldimines offer a viable option to
obtain multifunctional materials. The characterization of
surface and solubility properties of these materials provides
striking benefits to realize electrostatic association, H-bonding,
or donor−acceptor interactions and miscibility to enable the
development of some applications such as sensitive chemical
4
,5
6
bonding.
10
and biological sensors using LC-based materials. The LCs
The molecular shape in LCs is effective in the formation of
mesophase. Calamitic LCs consist of a rigid core with at least
two aromatic rings, which are covalently connected by linking
also have the ability to separate the structural isomers from
their mixtures if they are used as a stationary phase in a
column. Thus, interaction data of LCs with various liquids are
required in the separation techniques.
7
groups and flexible terminal chains. The various functional
groups can be incorporated for certain material properties. For
example salicylaldimines have been favorably employed in the
LC synthesis to establish mesogenic complexes showing novel
desirable physical properties by incorporating transition metal
Received: October 8, 2018
Accepted: February 12, 2019
8
atoms to mesogenic ligands.
©
XXXX American Chemical Society
A
DOI: 10.1021/acs.jced.8b00903
J. Chem. Eng. Data XXXX, XXX, XXX−XXX

Journal of Chemical & Engineering Data
Article
Inverse gas chromatography (IGC) at infinite dilution is a
useful and quite versatile technique applied for thermodynam-
ical characterization of a wide range of systems such as
polymers, LCs, composite materials, pharmaceutical solids,
a surface consisting of only methylene groups, that is,
D
polyethylene, given by, [γ[
= 35.6 + 0.058(293.2 − T)
CH
2
]
and ΔG[CH2] was obtained from the slope of the plot ΔGA
versus C atom numbers of the used n-alkanes.
1
1−13
etc.
The term “inverse” indicates that the stationary phase
The specific component of the Gibbs free energy of
of the chromatographic column is of interest, in contrast to
conventional gas chromatography. The retention data were
obtained by injection of some selected solvents called probes at
suitable temperatures. The surface properties of the material in
the column are determined from the retention data at lower
temperatures while the solubility characteristics are determined
from the retention data at the thermodynamical equilibrium
S
A
adsorption, −ΔG is related to the solid phase’s ability to
act as a donor (basic) or an acceptor (acidic) to the electrons.
D
To determine acid and base constants of the sample, the ΔG
A
values of the corresponding hypothetical n-alkanes are
subtracted from ΔG of the used polar solvents. The distance
A
between the ordinate values of the polar probes and the n-
S
A
14−16
alkane reference line gives − ΔG :
region at higher temperatures.
In this work, we determined the dispersive surface energy,
acid and base constants, and solubility data at higher
temperatures of a new chiral calamitic LC, DOPIMP, by
using the IGC technique.
i
y
V
j
N,n z
S
j
z
−ΔG = RT lnj
z
A
j
j
z
z
V
N,ref
(5)
k
{
where V and V
are the retention volumes for the polar
N,n
N,ref
solvent and the corresponding hypothetical n-alkane on their
reference line, respectively.
2
. THEORETICAL BASIS
.1. Surface Characterization. IGC is known as a
2
S
A
ΔG results from specific components of the adsorption
reasonable technique to measure surface properties of the
samples in the chromatographic column as a stationary
S
A
S
A
enthalpy (ΔH ) and entropy (ΔS ) between the examined
1
7
surface and polar solvent:
phase, and extensively applied for characterization of various
1
5
S
A
S
A
S
A
materials. Dispersive surface energy and acid−base constants
ΔG = ΔH − TΔS
(6)
of the solid material can be determined from the net retention
S
A
ΔH is related to the acidic or the basic character through the
equation given by Gutmann:
volume, V given as
N
2
3
V = QJ (t − t )T/(T )
N
R
A
f
(1)
S
A
−
ΔH = K (DN) + K (AN*)
(7)
A
D
2
where Q is carrier gas flow, J is the pressure correction factor
3
2
3
2
3
term and is given by J = [3(p /p ) − 1]/[2(p /p ) − 1]
where DN and AN* are Gutmann’s donor and modified
acceptor numbers, respectively, whereas K and K are acid
and base constants of the sample surface, respectively, which
are indicators reflecting its Lewis acidity and basicity.
and K can be determined by the slope
and intercept, respectively, of the straight line obtained by
i
0
i
0
where the inlet pressure is p and the outlet pressure is p , t
A
D
i
0
R
and t are retention times of the solvent and air, respectively;
A
Tf(K) and T(K) are temperatures of ambient and column,
respectively.
Consequently, K
A
D
Since the theoretical background is explained in detail in our
1
8−20
S
previous works,
study. VN is linked to the Gibbs free energy of adsorption
ΔG ) of the solvents on the sample in the column;
it is explained in summary in the present
plotting − ΔH /AN* versus DN/AN*. The ratio K /K
A D A
provides an empirical basis for the classification of the surface
with respect to acidity−basicity. The surface is considered to
be basic if the ratio is higher than 1 or vice versa.
(
A
ΔG = −RT ln(V ) + K
(2)
A
N
2.2. Solubility of the DOPIMP in the Solvents. If the
stationary phase is in the molten state in the chromatography
where R is the universal gas constant and K is a constant
column, the measured retention data can be used to determine
related the reference state. ΔG is the sum of its two
A
∞
D
the mole fraction activity coefficients at infinite dilution, γ , for
components, that is, dispersive (ΔG ) and specific (acid−
12
A
S
A
the probe solvents by using the equations developed by
base) (ΔG ). When n-alkanes are used as solvents, ΔG equals
A
24
25
D
A
Everett and Cruickshank
to ΔG because of the absence of specific interaction between
21
n-alkanes and the sample in the column.
In this case, ΔG is related to the dispersive components of
0
1
0
3
∞
i
y
jn RT z
p (B11 − V1 )
p J (2B13 − V1 )
ln γ1 ∞2 = ln
j
2
z
−
+
0
2
A
j
z
D
S
D
L
j
0 z
surface energies of the sample, γ and n-alkanes, γ ,
j V p z
RT
RT
N
1
{
22
k
respectively, as proposed by Schultz
(
8)
D
A
D D 1/2
−
ΔG = −ΔG = 2N a(γ γ )
where n is the number of moles of the nonvolatile material
used as the stationary phase in the column, p , B , and V are
the saturated vapor pressure, gaseous state second virial
coefficient, and molar volume of the solvent probe,
respectively, at column temperature, T(K). B13 is the mixed
second virial coefficient of the solvent probe and carrier gas.
A
A
S
L
(3)
2
0
1
0
1
11
where N is the Avogadro’s number and a is the cross-sectional
A
area of the solvent molecule.
2
3
On the other hand, Dorris and Gray proposed to
determine γ DS from the Gibbs free energy of adsorption
increment per mole of methylene group (ΔG[CH2]) using the
26
Guillett et al. stated that the last term in eq 8 can be ignored
relationship:
at moderate carrier gas pressures (less than 202.65 kPa). In this
case, eq 8 becomes
D
D
)1/2
−
ΔG[CH2] = 2N a
(γ γ
A [CH ]
S
[CH2]
(4)
2
0
1
0
i
y
jn RT z
p (B11 − V1 )
ln γ1 ∞2 = lnj
j
2
z
j
z
where a[CH2] is the surface area covered by one methylene
j
j
0 z
z
RT
V p
2
D
[
N
(9)
1
{
group (0.06 nm ) and γ
is the dispersive surface energy of
2
CH ]
k
B
DOI: 10.1021/acs.jced.8b00903
J. Chem. Eng. Data XXXX, XXX, XXX−XXX

Journal of Chemical & Engineering Data
Article
Table 1. Purities and Purification Methods of the Reagents
chemical name
S)-(-)-β-citronellol
palladium on carbon 10 wt. % loading (dry basis)
methanol
hydrobromic acid
sulfuric acid extra pure
abbreviation
source
Aldrich
ALFA.A120120
technical grade
ABCR-AB203595
Merck
Sigma-Aldrich
Aldrich
Merck
Merck
Merck
Supelco
Supelco
Supelco
Supelco
Sigma-Aldrich
Sigma-Aldrich
Merck
Supelco
Supelco
Sigma-Aldrich
Sigma-Aldrich
Supelco
CASRN
initial mole fraction purity purification method
(
7540-51-4
≥0.99
none
none
distillation
none
none
none
none
none
none
none
none
none
none
none
none
none
none
none
none
none
none
none
none
none
none
none
none
none
MeOH
HBr
48%
H SO
7664-93-9
32503-27-8
95-01-2
298-14-6
68-12-2
0.95−0.98
≥0.97
≥0.98
ACS
2
4
tetrabutylammonium hydrogen sulfate
TBAHS
2
,4-dihydroxy benzaldehyde
potassium hydrogen carbonate
N,N-dimethilformamid
p-toluenesulfonic acid monohydrate
chloroform
n-hexane
n-heptane
n-octane
n-nonane
n-decane
undecane
KHCO3
ACS
6192-52-5
67-66-3
TCM
Hx
Hp
O
N
D
≥0.99
≥0.99
≥0.99
≥0.99
≥0.99
≥0.99
≥0.99
≥0.998
≥0.995
≥0.98
≥0.99
≥0.998
≥0.998
≥0.997
≥0.995
≥0.99
≥0.995
≥0.998
110-54-3
142-82-5
111-65-9
111-84-2
124-18-5
16416-29-8
141-78-6
123-86-4
110-19-0
103-65-1
109-99-9
67-64-1
60-29-7
75-09-2
100-41-4
108-90-7
108-88-3
UD
EA
ethyl acetate
n-butyl acetate
iso-butyl acetate
n-propylbenzene
tetrahydrofurane
acetone
diethyl ether
dichloromethane
ethylbenzene
nBA
iBA
nPB
THF
Ace
DEE
DCM
EB
Supelco
Supelco
Supelco
Sigma-Aldrich
Sigma-Aldrich
Supelco
chlorobenzene
toluene
CB
T
∞
The values of γ of a solvent probe for the liquid material used
was injected into the chromatograph by injecting the air filled
up after all of the small amount solvent in the micropipette is
discharged into the air. Before the experiments, it was
determined that the retention time does not depend on the
sample size and flow rate of the carrier gas and eluted peaks are
sharp and reproducible. The column was conditioned at 373 K
for 24 h under a helium atmosphere. Transition temperatures
were measured, and optical investigations were carried out
using a Mettler FP-82 HT hot stage and a control unit in
conjunction with a Leica DM2700P polarizing microscope and
Leica DMC2900 digital camera. The associated enthalpies
were obtained from DSC-thermograms which were recorded
1
2
as stationary phase provide information related to their
intermolecular interaction. The fact that γ12 is equal to 1
indicates ideal mixing, while smaller and larger values than 1
show favorable and unfavorable interactions, respectively.
Since γ1 contains all of the deviations from the ideality, the
partial molar residual enthalpic (ΔH
components of the interaction at infinite dilution can be
estimated from the slope and intercept of a straight line
between logarithm of γ12 and reciprocal of the absolute
temperature according to eq 10
∞
∞
2
E,∞
E,∞
̅
) and entropic (ΔS
̅
)
1
1
∞
ΔH̅ E,∞
ΔS̅E,∞
ln γ1∞2
=
1
−
1
on a Perkin-Elmer DSC-7 with a heating and cooling rate of 10
(10)
−1
RT
R
°
C min . The purity of reagents and their purification
methods are given in Table 1.
3
. EXPERIMENTAL METHODS
.1. Materials and Instrumentations. Chromosorb-W
AW-DMCS-treated, 80/100 mesh) support material was
3.2. Synthesis and Characterization of DOPIMP.
DOPIMP was synthesized according to the procedure
3
27−29
described previously in the literature.
(S)-(-)-β-Citronel-
(
lol was reduced to (S)-3,7-dimethyl-1-octanol under catalytic
supplied from Merck AG Inc. Silane treated glass wool, used to
plug the ends of the column, was obtained from Alltech
Associates, Inc. Before measurements, we also confirmed that
the column walls and Chromosorb W (AW-DMCS) and
silanized glass wool did not adsorb any solvent.
hydrogenation conditions (H , 10% Pd/C in MeOH) in the
2
first reaction step of the DOPIMP. Then, (S)-3,7-dimethyloc-
tyl bromide was prepared from (S)-3,7-dimethyl-1-octanol by
reaction with 48% aq HBr/concn H SO using TBAHS as
2
4
30
catalyst. The aldehyde carrying the (S)-3,7-dimethyloctyloxy
A Hewlett-Packard 6890N model gas chromatograph with a
thermal conductivity detector was used to measure the
retention times of the solvents. The column was made of
stainless steel tubing with 3.2 mm outside diameter and 1 m
length. The LC was coated on the support by slow evaporation
of TCM as stirring the Chromosorb W (AW-DMCS) in the
LC solution. The amount of coated LC on the support was
determined as 9.15% by calcination. A trace amount of solvent
group was obtained by the reaction of 2,4-dihydroxybenzalde-
hyde with (S)-3,7-dimethyloctyl bromide, using KHCO as
3
base in DMF solvent. Finally, the condensation of the 4-((S)-
3,7-dimethyloctyloxy)-2-hydroxybenzaldehyde and 4-
(octyloxy)aniline in T using p-toluenesulfonic acid mono-
hydrate as catalyst yields new salicylaldimine-based chiral
31
calamitic LC, DOPIMP. Spectroscopic data and mesomor-
C
DOI: 10.1021/acs.jced.8b00903
J. Chem. Eng. Data XXXX, XXX, XXX−XXX

Journal of Chemical & Engineering Data
Article
phic properties for the DOPIMP LC were given in Mutlu
Yanic et al..
The phase transition temperatures and chemical structure of
DOPIMP are shown in Figure 1.
4. RESULTS AND DISCUSSION
.1. Surface Characterization of DOPIMP. At first, the
3
1
4
retention data were recorded at the temperatures between
room temperature and 125 °C in order to see the thermal
transition points if any. A transition point at 57 °C was
detected in the retention diagram drawn between ln V versus
N
1
/T, belonging to the crystalline-SmC* transition. Detection
of a different transition temperature in the IGC test compared
to DSC is common since the measured properties and
experimental conditions of these two techniques are quite
different. DSC measures the heat taken or given by the
substance, whereas IGC measures the retention time of the
sorbed probe molecules. In addition, DSC is a dynamic
technique but IGC is a static technique. The retention data at
the thermodynamic equilibrium region for which the variation
is a straight line should be used to obtain accurate results.
The adsorption properties of the DOPIMP surface were
investigated by IGC technique between 303.2 and 328.2 K at
the thermodynamic equilibrium absorption region which was
linear straight lines as seen in Figures 3 and 4. The net
Figure 1. Chemical structure and phase transition temperatures t
−
1
(
7
°C) and enthalpies ΔH [kJmol ] of DOPIMP (Perkin-Elmer DSC-
−
1
; heating rates 10 °C min ; abbrevations, Cr = crystalline, SmC* =
chiral smectic C phase, Iso = isotropic liquid phase).
The salicylaldimine-based chiral calamitic LC with a (S)-3,7-
dimethyloctyloxy group at one of the terminals, DOPIMP,
exhibits enantiotropic chiral smectic C* mesophase in a wide
temperature range. When the LC was cooled from the
isotropic liquid, the fingerprint texture of Cr and SmC*
phase was observed under the polarizing microscope as shown
in Figure 2a,b.
retention volumes, V , were obtained by the retention times
which were precise and reproducible to ± 0.01 min according
to the eq 1.
N
Figure 3. Net retention volumes V of nonpolar solvents: N (1), O
N
(2), Hp (3), and Hx (4).
Figure 2. Texture of the Cr and SmC* phase obtained between
crossed polarizers at 35 °C (a) and 60 °C (b) on cooling.
Figure 4. Net retention volumes V of polar solvents: THF (1), TCM
(2), DCM (3), Ace (4), and DEE (5).
N
D
DOI: 10.1021/acs.jced.8b00903
J. Chem. Eng. Data XXXX, XXX, XXX−XXX

Journal of Chemical & Engineering Data
Article
Using eqs 1−5, a dispersive component of the surface energy
D
S
γ of DOPIMP was calculated by the methods of Schultz and
Doris-Gray. The details of the methods were given in our
3
2,33
D
earlier papers.
The obtained γL values were given in a
linear line with their corresponding regression coefficients at a
temperature range from 303.2 to 328.2 K.
D
−2
Schultz:
γ /mJ m = 40.8 − 0.273 (T/K, 303.2)
S
2
R = 0.988
D
−2
Dorris-Gray: γ /mJ m = 41.4 − 0.215 (T/K, 303.2)
S
2
R = 0.975
It can be seen that there is not much discrepancy between
the values obtained from these two methods. The dispersive
−
2
surface energy of DOPIMP can be accepted as 41.1 mJ m at
0 °C as a mean of the values found from these methods. This
value is in agreement with the values of LCs reported as about
3
−
2
18,33
4
0 mJ m in the literature.
The acid−base characterization was implemented by means
Figure 6. Net retention volumes, V , of UD (1), D (2), N (3), O (4),
N
Hp (5), and Hx (6) on DOPIMP.
S
of ΔG which is the difference between the Gibbs free energies
A
S
A
of adsorption of polar and nonpolar probes. Then, ΔH of
polar probes was obtained from the slope of the straight line of
S
A
S
A
−
ΔG /T against 1/T. The values of ΔH were specified as
the degree of interaction between the surface of DOPIMP and
the selected polar solvents.
S
A
A plot of −ΔH /AN* versus DN/AN* was drawn with K
as the slope and K as the intercept using eq 7, and it is shown
A
D
in Figure 5. The obtained K and K are found to be 0.056 ±
A
D
Figure 7. Net retention volumes, V , of nPB (1), CB (2), EB (3),
N
nBA (4), T (5), IBA (6), and EA (7) on DOPIMP.
isomers of butyl acetates, that is, nBA and IBA, from their
mixtures by gas chromatography since their net retention
volumes are quite different.
The mole fraction activity coefficient of the probe solvents at
infinite dilution γ ∞1 were obtained from eq 9 and their values
2
0
1
0
1
were given in Table 2. The values of B , V , and p of the
S
11
Figure 5. Plot of −ΔH /AN* versus DN/AN*.
A
probe solvents were estimated by means of the data given in
34
the literature.
0
.014 and 0.118 ± 0.010, respectively. The ratio of K /KA
It can be seen obviously that the values of γ∞ decrease
D
12
(
=2.1) suggests that the surface of DOPIMP has a basic
considerably with increasing chain length of n-alkanes. It can
character at temperatures between 303.2 and 328.2 K. This can
be attributed to a lone pair of electrons on the nitrogen atom
of the DOPIMP structure.
be stated that the mixture of DOPIMP with n-octane
∞
represents almost ideal behavior at 388.2 K since γ1 equals
2
to 0.974. The data denote that the solubility of DOPIMP
increases considerably with molar mass and eventually the best
one is UD among the studied solvents. This implies that the
dominant interaction is through the long alkyl tails of
DOPIMP. This is also confirmed by increasing the solubility
of the aromatic hydrocarbons as the chain length of their alkyl
groups increases.
4.2. Solubility of DOPIMP. The net retention volumes, VN
of the solvents such as Hx, Hp, O, N, D, UD, CB, EB, nBA, T,
IBA, and EA on the liquid state DOPIMP were determined by
using eq 1 at temperatures between 368.2 and 398.2 K. The
percentage errors in V were not higher than ±0.3 using four
N
or five consecutive measurements of each data. The linearity of
the plots in Figures 6 and 7 indicates that a thermodynamic
equilibrium region is attained. It means that reasonable
thermodynamic data related to the solubility of DOPIMP
can be obtained at the region between 368.2 and 398.2 K.
It can be seen from the retention diagram in the Figure 7
that DOPIMP can be used as a stationary phase to separate the
It can be stated from the Table 2 that there is a specific
attractive interaction between the chlorine group of CB and
∞
DOPIMP since the values of γ decrease considerably with the
1
2
introduction of chlorine group instead of methyl group of T.
The increase of γ ∞1 with temperature indicates the exothermic
2
solubility of DOPIMP in the studied probe solvents.
E
DOI: 10.1021/acs.jced.8b00903
J. Chem. Eng. Data XXXX, XXX, XXX−XXX

Journal of Chemical & Engineering Data
Article
Table 2. Values of the Mole Fraction Activity Coefficients at
5. CONCLUSIONS
The dispersive surface energy, γ of DOPIMP was found as
∞
Infinite Dilution (γ ) of the Probe Solvents for DOPIMP at
D
S
1
2
a
Different Temperatures
2
4
1.1 mJ/m at 30 °C by averaging the values found from the
∞
2
methods proposed by Schultz and Dorris−Gray and decreased
with temperature. The value of K /K (=2.1) suggests that the
(
γ )×10
1
2
D
A
T(K)
368.2
76.96
373.2
80.07
378.2
80.40
383.2
388.2
81.95
393.2
83.77
398.2
84.51
surface of DOPIMP has somewhat basic character. DOPIMP
can be used as a stationary phase to separate the nBA and IBA
from their mixtures by gas chromatography.
p − p
i
0
(
kPa)
80.39
solvent
Hx
Hp
O
N
D
UD
EA
IBA
nBA
nPB
EB
The mole fraction activity coefficients of the probe solvents
734
140
938
191
1150
258
1470
322
1840
420
2270
549
129
2880
718
176
44.1
11.3
2.88
18.6
226
∞
at infinite dilution, (γ ) suggest that among the studied probe
1
2
solvents, UD is the best one for DOPIMP. The probe solvents
can be sorted according to their decreasing power as UD > D >
nPB > EA > N > EB > CB > nBA > O > T > Hp > Hx. All the
studied solvents show exothermic solubility behavior.
It can be concluded that IGC is a convenient method to
obtain quantitative data related to surface energetics and
solubility of a LC in various solvents to use in convenient
designs in new application fields.
27.5
5.63
1.18
0.233
4.21
34.6
18.6
2.50
7.77
40.8
8.37
38.4
8.24
1.80
0.379
5.48
48.5
27.2
3.60
10.9
53.3
11.9
53.4
12.1
2.58
0.578
7.19
68.2
36.8
4.97
14.6
76.0
15.9
71.5
16.3
3.81
0.902
8.99
91.9
51.2
7.46
21.6
98.4
22.9
97.4
22.6
5.45
1.37
11.3
125
70.3
10.1
29.1
134
31.2
7.78
1.88
14.7
166
95.2
13.9
38.7
176
127
19.6
53.7
231
ASSOCIATED CONTENT
T
CB
■
31.1
40.8
56.4
*
S
Supporting Information
a
∞
Standard uncertainties u are as follows: u(γ ) = 0.05; u(T) = 0.1 K,
The Supporting Information is available free of charge on the
ACS Publications website at DOI: 10.1021/acs.jced.8b00903.
1
2
u(p) = 0.07 kPa.
̅
Characterization of the DOPIMP based on H-, 13C
1
E,∞
The residual partial molar heat, ΔH
̅
and residual partial
1
E,∞
NMR (PDF)
molar entropy, ΔS
̅
of mixing were determined from the
slope and intercept, of the plot ln γ , versus 1/T, respectively,
1
∞
12
according to eq 10, and their values were given in Table 3. The
AUTHOR INFORMATION
■
Corresponding Author
E-mail: kurtaran90@yahoo.com.
Table 3. Values of Partial Molar Residual Gibbs Energy
*
E,∞
E,∞
E,∞
(
ΔG
̅
), Enthalpy (ΔH
̅
), and Entropy (ΔS
̅
) of the
1
1
1
ORCID
Probe Solvents for DOPIMP at 368.2 K
Fatih Cakar: 0000-0001-6192-1370
Ozlem Cankurtaran: 0000-0002-8383-1170
Funding
This research has been supported by Scientific Research
Projects Coordination Center of Yildiz Technical University,
Turkey (2015-01-02-DOP01).
E,∞
E,∞
E,∞
−
ΔH
̅
(kJ/mol)
55.1
−ΔS
̅
(kJ/mol K)
−ΔG
̅
(kJ/mol)
1
1
1
Hx
Hp
O
N
D
UD
nBA
IBA
EA
nPB
EB
ClB
T
0.166
0.181
0.193
0.200
0.210
0.224
0.197
0.197
0.175
0.196
0.192
0.189
0.185
−6.08
65.2
74.8
82.4
91.1
−1.07
3.94
8.76
13.6
18.5
5.06
3.22
−4.40
11.3
7.85
7.58
2.79
101
Notes
77.7
75.8
60.1
83.4
75.5
77.1
71.0
The authors declare no competing financial interest.
REFERENCES
■
(
1) Lagerwall, J. P. F.; Scalia, G. A new era for liquid crystal research:
Applications of liquid crystals in soft matter nano-, bio- and
microtechnology. Curr Appl Phys 2012, 12, 1387−1412.
(2) Kato, T.; Mizoshita, N.; Kishimoto, K. Functional liquid-
crystalline assemblies: Self-organized soft materials. Angew. Chem., Int.
Ed. 2006, 45, 38−68.
(
3) Bisoyi, H. K.; Kumar, S. Liquid-crystal nanoscience: an emerging
E,∞
negative values of ΔH
̅
for all of the studied solvents refer to
1
avenue of soft self-assembly. Chem. Soc. Rev. 2011, 40, 306−319.
(4) Tschierske, C. Liquid crystal engineering − new complex
mesophase structures and their relations to polymermorphologies,
nanoscale patterning and crystal engineering. Chem. Soc. Rev. 2007,
the exothermic solubility. It can be seen that all the residual
thermodynamic parameters (ΔG
negative sign and their absolute values increase with the
increasing solubility, that is, the smaller is the γ12 value, the
higher is the absolute value of the residual thermodynamic
parameters. The negative sign of ΔH
interactions between DOPIMP and probe solvents at infinite
E,∞
E,∞
E,∞
̅
, ΔH
̅
and ΔS
̅
) have a
1
1
1
∞
3
(
6, 1930−1970.
5) Kitzerow, H. S.; Bahr, C. Chirality in Liquid Crystals; Springer-
Verlag: New York, 2001.
6) Ocak, H.; Bilgin-Eran, B.; Tschierske, C.; Baumeister, U.; Pelzl,
E,∞
̅
refers to favorable
1
(
G. Effect of fluorocarbon chains on the mesomorphic properties of
chiral imines and their complexes with copper(II). J. Mater. Chem.
E,∞
dilution. The negatively signed ΔS
̅
implies that the probe
1
solvents make the DOPIMP more regular. However, since the
enthalpic contribution is higher than entropic contribution, the
values of Gibbs energy become negative for all of the probe
solvents except to Hx, Hp and EA.
2
(
009, 19, 6995−7001.
7) Goodby, J. W.; Collings, P. J.; Kato, T.; Tschierske, C.; Gleeson,
H.; Raynes, P. Fundamentals of Liquid Crystals. Handbook of Liquid
Crystals, 2nd ed.; Wiley-VCH: Weinheim, Germany, 2014; Vol 1.
F
DOI: 10.1021/acs.jced.8b00903
J. Chem. Eng. Data XXXX, XXX, XXX−XXX

Journal of Chemical & Engineering Data
Article
(
8) Hoshino, N. Liquid crystal properties of metal−salicylaldimine
(26) Guillet, J. E.; Romansky, M.; Price, G. J.; Mark, R. V. D. Inverse
Gas Chromatography, Characterization of Polymers and Other Materials;
ACS Symposium Series; American Chemical Society: Washington,
DC, 1989; Chapter 3.
complexes. Chemical modifications towards lower symmetry. Coord.
Chem. Rev. 1998, 174, 77−108.
(
9) Nesrullajev, A.; Bilgin Eran, B. Study of mesomorphism,
thermotropic properties and pitch in new chiral smectogenic imine
(27) Bilgin-Eran, B.; Ocak, H.; Tschierske, C.; Baumeister, U.
Synthesis and mesomorphism of fluoroalkylated platinum complexes.
Liq. Cryst. 2012, 39, 467−476.
compounds. J. Mol. Liq. 2015, 209, 25−32.
(
10) Xiaokang, D.; Kun-Lin, Y. Liquid crystal based optical sensor
for detection of vaporous butylamine in air. Sens. Actuators, B 2012,
73, 607−613.
11) Corpart, J. M.; Girault, S.; Juhue, D. Structure and surface
(28) Bilgin-Eran, B.; Tschierske, C.; Diele, S.; Baumeister, U.
Synthesis and mesomorphism of fluoroalkylated organometallic
mesogens. J. Mater. Chem. 2006, 16, 1136−1144.
1
(
properties of liquid crystalline fluoroalkyl polyacrylates: Role of the
(29) Nesrullajev, A.; Bilgin-Eran, B. Study of mesomorphism,
thermotropic properties and pitch in new chiral smectogenic imine
compounds. J. Mol. Liq. 2015, 209, 25−32.
spacer. Langmuir 2001, 17, 7237−7244.
(
12) Boudriche, L.; Hamdi, B.; Kessaissia, Z.; Calvet, R.; Chamayou,
A.; Dodds, J. A.; Balard, H. An assessment of the surface properties of
milled attapulgite using inverse gas chromatography. Clays Clay Miner.
(30) Guzeller, D.; Ocak, H.; Bilgin-Eran, B.; Prehm, M.; Tschierske,
C. Development of tilt, biaxiality and polar order in bent-core liquid
crystals derived from 4′-hydroxybiphenyl-3-carboxylic acid. J. Mater.
Chem. C 2015, 3, 4269−4282.
2
(
010, 58, 143−153.
13) Shillcock, I. M.; Price, G. J. Inverse gas chromatography study
of poly(dimethyl siloxane)-liquid crystal mixtures. Polymer 2003, 44,
027−1034.
(31) Mutlu Yanic, S.; Ocak, H.; Cakar, F.; Bilgin-Eran, B.; Gu
̈
zeller,
D.; Cankurtaran, O. Morphology and preparation of polymer
dispersed liquid crystals by solvent-induced phase separation method.
Optoelectron. Adv. Mater. 2017, 11 (1−2), 77−81.
1
(
14) Shi, B.; Wang, Y.; Jia, L. Comparison of Dorris−Gray and
Schultz Methods for the calculation of surface dispersive free energy
(
32) Eken Korkut, S.; Yazici, O.; Cakar, F. Surface and
by inverse gas chromatography. J Chromatogr A 2011, 1218, 860−
thermodynamic characterizations and secondary transition of novel
8
(
62.
phthalocyanine glass. J. Chem. Eng. Data 2018, 63, 1146−1153.
15) Benkacem, T.; Hamdi, B.; Chamayou, A.; Balard, H.; Calvet, R.
(33) Erol, I.; Cakar, F.; Ocak, H.; Cankurtaran, H.; Cankurtaran, O.;
Physicochemical characterization of a diatomaceous upon an acid
treatment: a focus on surface properties by inverse gas chromatog-
raphy. Powder Technol. 2016, 294, 498−507.
Bilgin Eran, B.; Karaman, F. Thermodynamic and surface character-
isation of 4-[4-((S)-citronellyloxy) benzoyloxy] benzoic acid thermo-
tropic liquid crystal. Liq. Cryst. 2016, 43, 142−151.
(
16) Uhlmann, P.; Schneider, S. Acid−base and surface energy
(34) Poling, B. E.; Prausnitz, J. M.; O’Connell, J. P. The properties of
characterization of grafted polyethylene using inverse gas chromatog-
gases and liquids; McGraw-Hill Companies, Inc.: 2001.
raphy. J Chromatogr A 2002, 969, 73−80.
(
17) Adamska, K.; Voelkel, A.; Berlinska, A. The solubility parameter
for biomedical polymers-application of inverse gas chromatography. J.
Pharm. Biomed. Anal. 2016, 127, 202−206.
(
18) Ocak, H.; Mutlu Yanic, S.; Cakar, F.; Bilgin Eran, B.; Guzeller,
D.; Karaman, F.; Cankurtaran, O. A study of the thermodynamical
interactions with solvents and surface characterisation of liquid
crystalline 5-((S)-3,7-dimethyloctyloxy)-2-[[[4-(dodecyloxy) phenyl]
imino]-methyl]phenol by inverse gas chromatography. J. Mol. Liq.
2
(
016, 223, 861−867.
19) Cakar, F.; Ocak, H.; Ozturk, E.; Mutlu-Yanic, S.; Kaya, D.; San,
N.; Cankurtaran, O.; Bilgin-Eran, B.; Karaman, F. Investigation of
thermodynamic and surface characterisation of 4-[4-(2-
ethylhexyloxy)benzoyloxy]benzoic acid thermotropic liquid crystal
by inverse gas chromatography. Liq. Cryst. 2014, 9, 1323−1331.
(
20) Ocak, H.; Sakar, D.; Cakar, F.; Cankurtaran, O.; Bilgin-Eran, B.;
Karaman, F. Use of inverse gas chromatography for the
physicochemical characterisation of a new synthesised liquid crystal:
(
S)-5-(2-methylbutoxy)-2-{[(4-dodecyloxyphenyl)imino]methyl}-
phenol. Liq. Cryst. 2008, 12, 1351−1358.
21) Karakehya, N.; Bilgic, C. Surface characterisation of
(
montmorillonite/PVC nanocomposites by inverse gas chromatog-
raphy. Int. J. Adhes. Adhes. 2014, 51, 140−147.
(
22) Hamieh, T.; Schultz, J. New approach to characterise
physicochemical properties of solid substrates by inverse gas
chromatography at infinite dilution: I. Some new methods to
determine the surface areas of some molecules adsorbed on solid
surfaces. J Chromatogr A 2002, 969, 17−25.
(
23) Dorris, G. M.; Gray, D. G. Adsorption of n-alkanes at zero
surface coverage on cellulose paper and wood fibres. J. Colloid
Interface Sci. 1980, 77, 353−362.
(
24) Everett, D. H. Effect of Gas Imperfection on G.L.C.
Measurements: A refined method for determining activity coefficients
and second virial coefficients. Trans. Faraday Soc. 1965, 61, 1637−
1
(
645.
25) Cruickshank, A. J. B.; Gainey, B. W.; Hicks, C. P.; Letcher, T.
M.; Moody, R. W.; Young, C. L. Gas-liquid chromatographic
determination of cross-term second virial coefficients using glycerol.
Benzene + nitrogen and benzene + carbon dioxide at 50°C. Trans.
Faraday Soc. 1969, 65, 1014−1031.
G
DOI: 10.1021/acs.jced.8b00903
J. Chem. Eng. Data XXXX, XXX, XXX−XXX