Preparation of some polyamides of aminodibenzo-18-crown-6 ,studying their liquid
crystalline properties ,and using in solid-liquid extraction
By
Nawal Mahgoub Suleman ,Abelgasim A.Abd Elrasoul and El Jali E.El Hassan
21-1‫ص‬-2012, ‫مجلة كلية التربية –جامعة الخرطوم –العدد السادس‬
LOGO
Abstract
Results
This study had been aimed for preparation of four models of polyamides of
dibenzo-18-crown-6 with mono acid chlorides . The prepared compounds
have been characterized using (IR) spectra ,and (CHN) mass spectra.. The
inherent viscosity of these polymers was measured , and was found to have
intermediate molecular weight .The liquid crystalline properties of these
polymers was also studied using deferential scanning Calorimeter(DSC),and
hot-stage microscope . These compounds have been used in the extraction of
the alkaline metal nitrates. The value of E% (D) was found to be increased
and the extraction of these ions was found in the manner
(K+>Rb+>Cs+>Na+>Li+),this due to that ion and the crown ether cavity are
The extraction percentage of polymers was found to be higher compared to
that of the monomers ,this may due to their liquid –crystalline polymers .
identical .
Introduction
These polymers were synthesized by solution polymerization of cis or transDADB18C6, with diacid chlorides in DMA .TMA was used as acid acceptor .
The structures of the synthesized polymers were verified by elemental
analysis and IR spectroscopy. The (CHN) are in good agreement with
calculated values based on repeating unit(table (1),together with yield %of
these polymers .The IR spectra shows characteristics absorption bands ,at
1500cm-1 (amide 11), 1580-1640cm-1 (amide 1),and 3130cm-1 (NH
stretching),see (Figure 2) ) which is chosen as representative example. The
liquid crystalline properties of these polymers was also studied using
deferential scanning Calorimeter(DSC),and hot-stage microscope (Figure 3)
The experimental data for the extraction of alkali metal nitrates by these
compounds was presented in tables, (2).Examining the data obtained ,several
observations can be drawn out regarding the studied parameters :
In general the data of extraction of these metal ions showed an increase in
E%(or D) values with time ,which is in agreement with the trend of the slow
kinetic solid –liquid extraction processes (Table 2) .
Crown compounds are, generally described 1 as macrocyclic compounds ,
having hetero atoms such as O, N, or S as electron donor atoms. Pedersen
synthesized a number of aromatic and alicyclic crown ethers 2,3, and
discovered that they are capable of complexation with salts of various metal
cations comprising all of group 1a, almost all of group 1b metal ions ,and
some of 11b,111a,1Vb metal ions .
Feigenbaum and Michel 4 prepared 4,4'-diaminodibenzo-18-crown-6
.Polyamides were prepared using cis-4,4'-diaminodibenzo-18-crown-65,6
.The mobility of Na+ and Rb+ in poly(dibenzo-18-crown-6)has been studied7.
The first example of main chain liquid-crystalline polymers containing
dibenzo-18-crown-6 was reported by Percec and Rodenhouse 8.
Methods and Materials
All chemical used are of high purity (98 %or more ).Techniques used :the
melting point measurement apparatus was designed by Electro Thermal
Company .Infra –red was recorded using Pye-Unicame IR spectrophotometer
modle SP1025 ,and Perkin-Elemer model 1310.1HNMR were recorded in
dutrated dimethylsulphoxide (10%wt/v)on Hitachi R24-60MHz
spectrophotometer. Elemental Analysis (CHN) was performed by 240C
Perkin-Elemer Elemental Analyzer .All DSC measurement were with DSC-7of
perkin company .Texture observationwere carried out using Olympous
Polarizing Microscope equipped with photomicrographic system type PM10AD .Hot-stage type HTM600 supplied by Meter Company (Switzerland)was
used for heating the sample placed between glass slide and overslip.
The shaking apparatus was Scientific Technicals Suppliers Frankfurt WGermany.UV-Visible Spectrophotometer 4050 LKB Biochrom Ultraspec
11,with tow matched quartz cells was used .Viscosity was measured using
viscosity apparatus type AVS400 by Schott Gerate .
Preparation of the polyamides of diaminodibenzo18-crown-6
These compounds were prepared under dry nitrogen atmosphere by
adding dropwise the appropriate acid or diacid chloride (3 mmole) to
0.59g(1.5mmole),and 1.2g (3mmole)of DADB18C6 in a mixture of 5ml of
DMAC ,and 5ml of TEA. The reaction mixture was stirred overnight at room
temperature ,then poured into cold water(100ml).The precipitate was
separated by filtration ,washed with 0.1 M HCl Solution ,saturated solution of
soduium bicarbonate ,and then distilled water ,finally dried under reduced
pressure at 500C (Figure 1).
CHART or
PICTURE
Figure_1 polyamides of diaminodibenzo18-crown-6
Extraction of alkali metals nitrates (LiNO3,Na NO3, KNO3,CS NO3,andRb
NO3
Taking different concentrations of KNO3,a calibration curve of nitrates
was elaborated ,measuring the absorbance at 302 nm. For extraction of the
alkali metals nitrates the experiments were performed by shaking the mixture
of o.o36 g ofDB18C6 and 10 ml of the extracted solution (10-4 M) for
5,10,…….60 minutes ,and overnight , then the absorbance of the nitrate
solution was measured at each time (represent the absorbance of the
unreacted nitrate ion).The percentage of the extracted nitrate ion was
determined by difference between the absorbance of nitrate ion at zero time
and that at appropriate time of extraction .Similar procedure was repeated for
DNDB18C6(0.045 g),DADB18C6(0.039 g)and polyamide of DADB18C6(0.1
g).
Figure_2 IR spectra of model
compound (II)
Figure_3 DSC thermograms of
polyamides (V-VIII)
Table_1 CHN data , inhᶯ dl/g and yield % for polyamides
No
Model
Calculated
Found
C%
H%
N%
C%
yield %
ᶯinh
dl/g
H% N%
V
-[CO-(CH2)3-CO-NH-Trans-NH-]n-
61.72
6.22
5.80
61.88
6.22
5.76
83.9
0.8
V1
-[CO-(CH2)4-CO-NH-Trans-NH-]n-
62.39
6.22
5.29
62.19
6.22
5.60
76.5
0.4
V11
-[CO-(CH2)7-CO-NH-Trans-NH-]n-
63.95
6.22
5.01
63.89
6.22
5.14
71.4
0.9
V111
-[CH-(CH2)8-CO-NH-Trans-NH-]n-
64.50
6.22
5.89
64.38
6.22
5.01
99.2
0.6
1X
-[CO-(CH2)3-CO-NH-Cis-NH-]n-
61.72
6.22
5.62
61.60
6.22
5.76
98.7
0.3
X
-[CO-(CH2)4-CO-NH- Cis -NH-]n-
62.39
6.22
5.34
62.01
6.22
5.60
17.5
0.4
X1
-[CO-(CH2)8-CO-NH- Cis -NH-]n-
64.50
6.22
4.92
64.39
6.22
5.01
83.3
0.3
Table_2 Effect of time on extraction by polyamide of DADB18C6 (V1)
Time (min)
E%
Li+
Na+
K+
5
9.5
13.3
62.9
10
14.3
18.1
71.4
15
19.1
27.7
20
23.8
25
D
Rb+
Cs+
Li+
Na+
K+
Rb+
Cs+
29.6
21..3
10
15
169
41.9
27
40.9
34..0
16
22
250
96.2
54
75.7
54.6
40.4
23
38
311
120
67
27.7
85.7
61.4
46.8
31
38
600
158
88
23.8
33.7
90.0
65.9
51.1
31
50
900
193
104
30
23.8
38.6
92.9
72.4
55.3
31
62
1300
266
123
35
28.6
42.2
94.3
75.0
57.5
40
72
1650
300
135
40
28.6
44.6
94.3
77.3
61.7
40
80
1650
340
161
45
33.3
48.2
94.3
77.3
63.8
57
93
1650
340
176
50
38.1
53.0
95.7
79.6
66.0
61
112
2233
388
193
55
42.9
65.6
95.7
81.8
70.2
57
130
2233
450
235
60
42.9
63.9
97.1
81.8
72.3
57
176
3400
450
261
1440
47.6
66.3
98.6
84.1
74.5
90
196
6900
528
291
Overnight
Conclusions
1. Solution polymerization is a good method for the synthesis of these
polymers.
2. All polymers are of moderate molecular weight.
3. All models and polymers derived from trans -DADB18C6 moiety exhibited
liquid crystalline properties ,while those derived from cis- DADB18C6 did not
show any liquid crystalline properties .
4.
References
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3235(1991).
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