Liquid crystalline behavior of binary mixtures of structurally dissimilar mesogens and nonmesogens

Article abstract of DOI:10.1080/15421406.2013.766920

We have studied eight binary systems comprising three enantiotropic nematogens, namely 4-(4′-n-butyloxybenzoyloxy)phenylazo-4″- fluorobenzene, 4-(4′-n-butyloxybenzo yloxy)benzylidene-4″-fluoro aniline, and 4-(4′-n-heptyloxybenzoyloxy)phenylazo-4″-fl uorobenzene; a monotropic nematogen, viz. 4-(4′-n-dodecyloxybenzoyloxy) napthylazo-4″-fluorobenzene; and three nonmesogens, viz. 4-(4′-n-butyloxy benzoyloxy)benzalde hyde, 4-methoxybenzylidene-4′- chloroaniline, and 4-methoxybenzylidene-4′-toluidine. The central linkage, terminal group, and central ring system of the components have been varied systematically and the effect of these variations has been evaluated on the liquid crystalline properties of the binary mixtures. The mixed mesomorphic properties of these systems are discussed on the basis of their phase diagrams.

Full text of DOI:10.1080/15421406.2013.766920

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Liquid Crystalline Behavior of Binary
Mixtures of Structurally Dissimilar
Mesogens and Nonmesogens
Jayrang S. Dave a , Purvang D. Patel a & Himanshu S. Bhatt a
a Applied Chemistry Department, Faculty of Technology and
Engineering , M. S. University of Baroda , Vadodara , India
Published online: 22 Apr 2013.
To cite this article: Jayrang S. Dave , Purvang D. Patel & Himanshu S. Bhatt (2013) Liquid Crystalline
Behavior of Binary Mixtures of Structurally Dissimilar Mesogens and Nonmesogens, Molecular Crystals
and Liquid Crystals, 575:1, 8-21, DOI: 10.1080/15421406.2013.766920
To link to this article: http://dx.doi.org/10.1080/15421406.2013.766920
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Mol. Cryst. Liq. Cryst., Vol. 575: pp. 8–21, 2013
Copyright © Taylor & Francis Group, LLC
ISSN: 1542-1406 print/1563-5287 online
DOI: 10.1080/15421406.2013.766920
Liquid Crystalline Behavior of Binary Mixtures
of Structurally Dissimilar Mesogens
and Nonmesogens
JAYRANG S. DAVE,∗ PURVANG D. PATEL,
AND HIMANSHU S. BHATT
Applied Chemistry Department, Faculty of Technology and Engineering,
M. S. University of Baroda, Vadodara, India
We have studied eight binary systems comprising three enantiotropic nematogens,
namely 4-(4ꢀ-n-butyloxybenzoyloxy)phenylazo-4ꢀꢀ-fluorobenzene, 4-(4ꢀ-n-butyloxybenzo
yloxy)benzylidene-4ꢀꢀ-fluoro aniline, and 4-(4ꢀ-n-heptyloxybenzoyloxy)phenylazo-4ꢀꢀ-fl
uorobenzene; a monotropic nematogen, viz. 4-(4ꢀ-n-dodecyloxybenzoyloxy)napthylazo-
4ꢀꢀ-fluorobenzene; and three nonmesogens, viz. 4-(4ꢀ-n-butyloxy benzoyloxy)benzalde
hyde, 4-methoxybenzylidene-4ꢀ-chloroaniline, and 4-methoxybenzylidene-4ꢀ-toluidine.
The central linkage, terminal group, and central ring system of the components have
been varied systematically and the effect of these variations has been evaluated on the
liquid crystalline properties of the binary mixtures. The mixed mesomorphic properties
of these systems are discussed on the basis of their phase diagrams.
Keywords Binary mixtures; emergence; enantiotropic nematic; monotropic nematic;
nonmesogen; structurally dissimilar
Introduction
Physical properties of individual mesogens may or may not undergo modifications in
their mixtures. Sometimes, the modifications become characteristic, thereby making the
study of mixtures important. Earlier studies [1–7] have suggested the formation of mixed
mesomorphism by mixing compounds where none, one, or both of them are mesogens.
Emergence of the mesophase [8], increase or decrease in the mixed mesomorphic ranges and
thermal stabilities, and study of the factors that influence the modifications have received
greater attention. The binary mixtures of mesogens have provided better formulations for
applications in different field [9].
We have re-reported binary systems of structurally similar and dissimilar mesogens
and nonmesogens [10]. Continuing our research in this field, we report here four binary
systems consisting of structurally dissimilar mesogens and the study of their effect on
mixed mesomorphism, arising due to the differences in structural characteristics of these
components.
∗Address correspondence to Jayrang S. Dave, Applied Chemistry Department, Faculty of Tech-
nology and Engineering, M. S. University of Baroda, Vadodara 390 001, India. Tel.:+91-265-2434188
Ext. 212; Fax: +91-265-2423898. E-mail: jayrangdave@yahoo.com
8

Liquid Crystalline Behavior of Binary Mixtures
9
We have also reported binary systems of mesogens and nonmesogens [11]. Continuing
our research in this field, we report here eight binary systems consisting of nonmesogen
(A1 = BBB [12], A2 = MBCA, A3 = MBT), monotropic nematogen (A4 = DNFB), and
enantiotropic nematogen (B1 = BPFB [13], B2 = BBFA, B3 = HPFB [13]) (Scheme 1).
The binary systems studied are (I) BBB + BPFB, (II) BBB + BBFA, (III) MBCA +
BBFA, (IV) MBCA + HPFB, (V) MBT + BBFA, (VI) MBT + HPFB, (VII) DNFB +
BPFB, and (VIII) DNFB + BBFA.
Scheme 1. The structural formula of the components.

10
J. S. Dave et al.
Experimental
All the chemicals are of Merck grade and used as received. 4-n-alkoxybenzoicacids
and 4-n-alkoxy benzoylchlorides are synthesized by the modified method of Dave
and Vora [14]. 4-hydroxy phenylazo-4ꢀ-fluorobenzene and 4-hydroxynapthylazo-4ꢀ-fluoro
benzene are synthesized by the reported method in Ref. [15]. Condensation of (1) 4-
hydroxybenzaldehyde with 4-n-butyloxybenzoylchloride, (2) 4-hydroxynapthylazo-4ꢀ-fluo
robenzene with 4-n-dodecyloxybenzoylchloride, (3) 4-hydroxy phenylazo-4ꢀ-fluorobenz
ene with 4-n-butyloxybenzoylchloride, and (4) 4-hydroxyphenylazo-4ꢀ-fluorobenzene with
4-n-heptyloxybenzoylchloride are done by known methods [16].
4-methoxybenzylidene-4ꢀ-choroaniline (A2), 4-methoxybenzylidene-4ꢀ-toluidine
(A3), and 4-(4ꢀ-n-butyloxybenzoyloxy)benzylidene-4ꢀꢀ-fluoroaniline (B2) are synthe-
sized by taking equimolar quantities of 4-methoxybenzaldehyde with 4-chloroaniline,
4-methoxybenzaldehyde with 4-toluidine, and 4-(4ꢀ-n-butyloxybenzoyloxy)benzaldehyde
with 4-fluoroaniline, respectively, in minimum quantity of ethanol with a few drops of
glacial acetic acid and refluxing it for a period of 6–8 hours. The product is filtered, dried,
and recrystallized from ethanol until constant transition temperatures are obtained. The
synthetic route is shown in Scheme 2. Their infrared (IR) spectra are recorded on a Perkin
Elmer GX-FTIR:
Scheme 2. Synthetic route for components A1, A2, A3, A4, B1, B2, and B3.

Liquid Crystalline Behavior of Binary Mixtures
Fourier Transform Infrared (Nujol, KBr pellets, cm−1):
11
Component A1 4-(4ꢀ-n-butyloxybenzoyloxy)benzaldehyde (BBB)
2953, 2939, 1729 (ester), 1680 (aldehyde), 1600, 1253, 1066 (ether), 690
Component A2 4-methoxybenzylidene-4ꢀ-chloroaniline (MBCA)
2957, 2915, 1602, 1390, 1170 (azomethane), 1255, 1082 (ether), 692
Component A3 4-methoxybenzylidene-4ꢀ-toludine (MBT)
2939, 2924, 1608, 1393, 1170 (azomethane), 1255, 1078 (ether), 694
Component A4 4-(4ꢀ-n-dodecyloxybenzoyloxy)napthylazo-4ꢀꢀ-fluorobenzene (DNFB)
2950, 2926, 1733 (ester), 1606, 1359, 1170 (azo), 1259, 1064 (ether), 690
Component B1 4-(4ꢀ-n-butyloxybenzoyloxy)phenylazo-4ꢀꢀ-fluorobenzene (BPFB)
2958, 2920, 1729 (ester), 1597, 1496, 1389, 1199 (azo), 1258, 1073 (ether), 969, 761,
692.
Component B2 4-(4ꢀ-n-butyloxybenzoyloxy)benzylidene-4ꢀꢀ-fluoroanilinne (BBFA)
2955, 2916, 1737 (ester), 1606, 1396, 1170 (azomethane), 1259, 1064 (ether), 694
Component B3 4-(4ꢀ-n-heptyloxybenzoyloxy)phenylazo-4ꢀꢀ-fluorobenzene (HPFB)
2959, 2928, 1739 (ester), 1608, 1359, 1174 (azo), 1255, 1062 (ether), 692
Preparation and Study of Binary Mixtures
The components are weighted in known proportions and melted together in fusion tubes.
They are thoroughly mixed in their melt to obtain a homogeneous mixture, after which they
are cooled. This procedure is repeated three times. The solid obtained is finally ground and
used for determining transition temperatures, by using a Leitz laborlux 12 POL polarizing
microscope fitted with a Kofler heating stage. Figure 1 shows the photomicrographs of
some of the representative mixtures.
Results and Discussion
Binary System I: BBB (A1) + BPFB (B1)
In this system (Table 1, Fig. 2), component A1 is nonmesogen (Cr 91.5 I), whereas
B1 is nematogen (Cr 110 N 209 I), showing the nematic mesophase with marble texture.
The phase diagram of this system shows that the nematic phase emerges in enantiotropic
form by the addition of as low as 10.97 mole% of B1 and continues to be exhibited till the
addition of 90.69 mole% of B1. The mixed nematic phase also shows marble texture. As
the concentration of B1 increases, the mixed nematic mesophase range increases; eutectic
point is obtained at 47◦C at 40.25 mole% of B1 and maximum mesophase range of 131◦C
is observed at 90.69 mole% of B1. In this system, the N–I curve shows rising tendency,
with steep increase from 70.10 mole% of B1 and then a fall of 12◦C at 100 mole% of B1.
Thus, the N–I curve shows nonlinear behavior. Some of the binary mixtures supercool up
to about 40◦C.

12
J. S. Dave et al.
Table 1. Binary system I: BBB (A1) + BPFB (B1)
Transition temperature (◦C)
Mole% B1
Nematic
Isotropic
0
—
58
60
59
47
58
60
80
82
90
110
91.5
85
98
10.97
20.92
30.77
40.25
50.60
60.73
70.10
80.46
90.69
100
118
132
151
151
175
210
221
209
Figure 1. Photomicrographs of the textures of some of the representative mixtures.

Liquid Crystalline Behavior of Binary Mixtures
13
Figure 2. Phase diagram of binary system I: BBB (A1) + BPFB (B1).
Binary System II: BBB (A1) + BBFA (B2)
In this system (Table 2, Fig. 3), component A1 is nonmesogen (Cr 91.5 I), whereas
B2 is nematogen (Cr 108 N 244 I), showing the nematic mesophase with marble texture.
Here also, the nematic phase emerges in enantiotropic form by addition of as low as 10.54
mole% of B2 and continues to be exhibited till the addition of 90.57 mole% of B2. The
mixed nematic phase also shows marble texture. As the concentration of B2 increases,
the mixed nematic mesophase range increases. Eutectic point is obtained at 65◦C at 69.94
mole% and maximum mesophase range of 140◦C is observed at 90.57 mole% of B2. In this
Table 2. Binary system II: BBB (A1) + BBFA (B2)
Transition temperature (◦C)
Mole% B2
Nematic
Isotropic
0
—
47
52
50
48
70
80
65
91.5
87
10.54
19.52
30.25
40.98
49.46
60.51
69.94
80.66
90.57
100
105
162
145
150
191
200
224
245
244
100
105
108

14
J. S. Dave et al.
Figure 3. Phase diagram of binary system II: BBB (A1) + BBFA (B2).
system, the N–I curve shows rising tendency, with a jump at 30.25 mole% of B2; thus, the
N–I curve shows nonlinear behavior. Some of the binary mixtures supercool up to about
40◦C.
Binary System III: MBCA (A2) + BBFA (B2)
This system (Table 3, Fig. 4) consists of component A2, which is nonmesogen (Cr 94 I),
and component B2, which is nematogen (Cr 108 N 244 I), showing the nematic mesophase
with marble texture. The mesogenic characteristic emerges in monotropic form by the
Table 3. Binary system III: MBCA (A2) + BBFA (B2)
Transition temperature (◦C)
Mole% B2
Nematic
Isotropic
0
8.93
—
(79)
(75)
80
71
86
83
91
106
105
108
94
80
83
19.60
28.13
39.71
50.17
59.95
69.24
79.57
90.06
100
89
128
176
157
200
192
206
244
Note. Values within parentheses indicate monotropic transitions.

Liquid Crystalline Behavior of Binary Mixtures
15
Figure 4. Phase diagram of binary system III: MCBA (A2) + BBFA (B2).
addition of as low as 8.93 mole% of B2, which becomes enantiotropic by addition of 28.13
mole% of B2 and continues to be exhibited till the addition of 90.06 mole% of B2. The
mixed nematic phase shows marble texture. As the concentration of B2 increases, the mixed
nematic mesophase range increases. Eutectic point is obtained at 71◦C at 39.71 mole% of
B2 and maximum mesophase range of 109◦C is observed at 69.24 mole% of B2. In this
system, the N–I curve shows nonlinear behavior with overall rising tendency, with increase
in concentration of B2. Some of the binary mixtures supercool up to about 50◦C.
Binary System IV: MBCA (A2) + HPFB (B3)
Table 4. Binary system IV: MBCA (A2) + HPFB (B3)
Transition temperature (◦C)
Mole% B3
Nematic
Isotropic
0
9.76
—
—
(38)
60
64
62
66
50
60
66
83
94
90
83
86
89
98
92
122
129
136
182
19.34
29.32
39.75
49.77
59.56
69.22
79.48
89.08
100
Note. Values within parentheses indicate monotropic transitions.

16
J. S. Dave et al.
Figure 5. Phase diagram of binary system IV: MBCA (A2) + HPFB (B3).
Phase diagram of this system (Table 4, Fig. 5) shows that the nematic phase emerges as
monotropic form by the addition of 19.34 mole% of nematogen B3 (Cr 83 N 182 I) in
nonmesogen A2 (Cr 94 I). The monotropic nematic phase is transformed into enantiotropic
form by addition of 29.32 mole% of B3 and continues to be exhibited till the addition of
89.08 mole% of B3. The mixed nematic phase shows threaded texture. As the concentration
of B3 increases, the mixed nematic mesophase range also increases. Eutectic point is
obtained at 50◦C at 69.22 mole% of B3 and maximum mesophase range of 72◦C is observed
at the same concentration. In this system, the N–I curve shows nonlinear behavior, with
overall rising tendency with increase in the concentration of B3. Some of the binary mixtures
supercool up to about 45◦C.
Table 5. Binary system V: MBT (A3) + BBFA (B2)
Transition temperature (◦C)
Mole% B2
Nematic
Isotropic
0
9.43
—
—
96
78
19.55
29.03
39.72
49.80
59.25
69.01
79.43
89.07
100
(54)
78
75
71
60
82
111
126
146
169
191
211
226
244
80
106
100
108
Note. Values within parentheses indicate monotropic transitions.

Liquid Crystalline Behavior of Binary Mixtures
17
Figure 6. Phase diagram of binary system V: MBT (A3) + BBFA (B2).
Binary System V: MBT (A3) + BBFA (B2)
In this system (Table 5, Fig. 6), component A3 is nonmesogen (Cr 96 I), whereas component
B2 is nematogen (Cr 108 N 244 I), showing the nematic mesophase with marble texture. The
nonmesogenic component A3 is transformed into monotropic nematogen by the addition of
19.55 mole% of B2. The monotropic nematic phase is transformed into enantiotropic form
by the addition of 29.03 mole% of B2 and continues to be exhibited till the addition of 89.07
mole% of B2. The mixed nematic phase also shows marble texture. As the concentration of
B2 increases, the mixed nematic mesophase range also increases. Eutectic point is obtained
at 60◦C at 59.25 mole% of B2 and maximum mesophase range of 126◦C is observed at
89.07 mole% of B2. In this system, the N–I curve shows nonlinear behavior, with steep
rising tendency with increase in the concentration of B2. Some of the binary mixtures
supercool up to about 45◦C.
Binary System VI: MBT (A3) + HPFB (B3)
In this system (Table 6, Fig. 7), component A3 is nonmesogen (Cr 96 I), whereas component
B3 is nematogen (Cr 83 N 182 I), showing the nematic mesophase with marble texture. The
nonmesogenic A3 is transformed into monotropic nematic phase by the addition of as low
as 8.96 mole% of B3. The monotropic nematic phase is transformed into enantiotropic form
by the addition of 59.15 mole% of B3 and continues to be exhibited till the addition of 89.84
mole% of B3. The mixed nematic phase also shows marble texture. As the concentration
of B3 increases, the mixed nematic mesophase range increases. Eutectic point is obtained
at 60◦C at 68.83 mole% of B3 and maximum mesophase range of 54◦C is also observed at
68.83 mole% of B3. In this system, the N–I curve shows nonlinear behavior, with zig-zag
tendency with increase in the concentration of B3. Some of the binary mixtures supercool
up to about 50◦C.

18
J. S. Dave et al.
Table 6. Binary system VI: MBT (A3) + HPFB (B3)
Transition temperature (◦C)
Mole% B3
Nematic
Isotropic
0
8.96
—
—
(50)
80
71
65
73
60
77
79
83
96
70
79
20.51
29.13
38.77
50.26
59.15
68.83
79.42
89.84
100
106
110
100
121
114
126
129
182
Note. Values within parentheses indicate monotropic transitions.
Binary System –VII: DNFB(A4) + BPFB(B1)
In this system (Table 7, Fig. 8), both components A4 and B1 are mesogenic in nature; A4 is
monotropic nematogen (Cr (50) N 90 I), whereas B1 is enantiotropic nematogen (Cr 110 N
209 I); the nematic mesophase shows schlieren texture in A4, whereas marble texture in
B1. The monotropic nematic phase of A4 is transformed into enantiotropic nematic phase
by the addition of as low as 11.06 mole% of B1 and continues to be exhibited till the
addition of 90.79 mole% of B1. The mixed nematic phase shows schlieren texture. As
the concentration of B1 increases, the mixed nematic mesophase range increases. Eutectic
point is obtained at 79◦C at 71.40 mole% of B1 and maximum mesophase range of 121◦C
Figure 7. Phase diagram of binary system VI: MBT (A3) + HPFB (B3).

Liquid Crystalline Behavior of Binary Mixtures
19
Table 7. Binary system VII: DNFB (A4) + BPFB (B1)
Transition temperature (◦C)
Mole% B1
Nematic
Isotropic
0
(50)
68
71
75
90
95
96
79
109
89
90
98
11.06
20.76
30.18
40.43
50.47
60.83
71.40
80.47
90.79
100
106
114
130
145
159
170
184
210
209
110
Note. Values within parentheses indicate monotropic transitions.
is observed at 90.79 mole% of B1. In this system, the N–I curve shows rising tendency,
with slight increase at 90.79 mole% of B1; thus, the N–I curve shows nonlinear behavior.
Some of the binary mixtures supercool up to about 50◦C.
Binary System VIII: DNFB (A4) + BBFA (B2)
Figure 8. Phase diagram of binary system VII: DNFB (A4) + BPFB (B1).

20
J. S. Dave et al.
Table 8. Binary system VIII: DNFB (A4) + BBFA (B2)
Transition temperature (◦C)
Mole% B2
Nematic
Isotropic
0
(50)
64
66
82
90
92
88
106
99
110
108
90
89
86
10.92
21.52
30.78
40.85
51.27
60.44
70.78
80.16
90.94
100
104
118
118
135
173
180
225
244
Note. Values within parentheses indicate monotropic transitions.
In this system (Table 8, Fig. 9), both components A4 and B2 are mesogenic in nature;
A4 is monotropic nematogen (Cr (50) N 90 I), whereas component B2 is enantiotropic
nematogen (Cr 108 N 244 I); the nematic mesophase shows schlieren texture in A4,
whereas marble texture in B2. The monotropic nematic phase of A4 is transformed into
enantiotropic nematic phase by the addition of as low as 10.92 mole% of B2 and continues
to be exhibited till the addition of 90.94 mole% of B2. The mixed nematic phase also shows
schlieren texture. As the concentration of B2 increases, the mixed nematic mesophase
range increases. No eutectic point is obtained and maximum mesophase range of 81◦C is
observed at 80.16 mole% of B2. In this system, the N–I curve shows rising tendency, with
steep rise from 80.16 mole% of B2; thus, the N–I curve shows nonlinear behavior. Some
of the binary mixtures supercool up to about 50◦C.
Figure 9. Phase diagram of binary system VIII: DNFB (A4) + BBFA (B2).

Liquid Crystalline Behavior of Binary Mixtures
21
Conclusion
All the eight binary systems studied show nonlinear behavior in the N–I curve. This may
be due to the fact that all of these binary systems consist of two structurally dissimilar com-
ponents [17,18]. It is observed that all the binary mixtures exhibit good mixed mesophase
range, which is more than the mesophase range of individual components. In the binary
systems with the nonmesogen as one of the components, the nematic phase emerges either
in monotropic or in enantiotropic form with the addition of as low as 10 to 20 mole% of
the nonmesogenic component in the mixture.
Acknowledgments
The authors are thankful to Prof. P.T. Deota, Head, Applied Chemistry Department, Faculty
of Technology and Engineering, M. S. University of Baroda, Vadodara, India, for providing
laboratory facilities and encouragement.
References
[1] Dave, J. S., & Vasanth, K. L. (1966). Mol. Cryst. Liq. Cryst., 2, 125–133.
[2] Dave, J. S., Patel, P. R., & Vasanth, K. L. (1969). Mol. Cryst. Liq. Cryst., 8, 93–100.
[3] Dave, J. S., Menon, M. R., & Patel, P. R. (2003). Mol. Cryst. Liq. Cryst., 392, 83–95.
[4] Vora, R. A., Gupta, R., & Patel, K. (1991). Mol. Cryst. Liq. Cryst., 209, 251–263.
[5] Prajapati, A. K., Patel, N. S., & Lad, V. G. (2000). Mol. Cryst. Liq. Cryst., 348, 41–51.
[6] Vora, R. A. & Rajput, S. J. (1991). Mol. Cryst. Liq. Cryst., 209, 265–277.
[7] Govindaiah, T. N., Nagappa, Sathyanarayana, P. M., Mahadeva, J., & Sreepad, H. R. (2011).
Mol. Cryst. Liq. Cryst., 548, 55–60.
[8] Lohar, J. M., & Dave, J. S. (1983). Mol. Cryst. Liq. Cryst., 103, 181–192.
[9] Hird, M., Goodby, J. W., & Toyne, K. J. (2001). Mol. Cryst. Liq. Cryst., 360, 1–15.
[10] Dave, J. S., Menon, M. R., & Patel, P. R. (2002). Proc. Indian Acad. Sci., 114(3), 213–221.
[11] Dave, J. S., & Menon, M. R. (1997). J. Indian Chem. Soc., 74, 809.
[12] Dave, J. S., & Kurian, G. (1975). J. Physique, 36, C1-403-C1-407.
[13] Dave, J. S., Upasani, C. B., & Patel, P. D. (2010). Mol. Cryst. Liq. Cryst., 533, 73–81.
[14] Dave, J. S., & Vora, R. A. (1970). Photochemical and Thermal stability Studies on a Liquid
Crystal Mixture of Cyanobiphenyls. In: J. F. Johnson & R. S. Porter (Eds.), Liquid Crystals and
Ordered Fluids, Plenum Press: New York, p. 477.
[15] (1989). B. S. Furniss, A. J. Hannford, P. W. G. Smith, & A. R. Tatchell (Eds.). (1989), Aliphatic
Compounds. Vogel’s Textbook of Practical Organic Chemistry (4th ed.), Singapore: Longman
Singapore, pp. 563–649.
[16] (1989). B. S. Furniss, A. J. Hannford, P. W. G. Smith, & A. R. Tatchell (Eds.). (1989), Aliphatic
Compounds. Vogel’s Textbook of Practical Organic Chemistry (4th ed.), Singapore: Longman
Singapore, pp. 697–698.
[17] Gupta, R., & Vora, R. A. (1984). Mol. Cryst. Liq. Cryst., 106, 147–159.
[18] Dave, J. S., Menon, M. R., & Patel, P. R. (2001). Mol. Cryst. Liq. Cryst., 365, 581–591.