The document summarizes research on synthesizing macrocyclic chelating agents for removing and concentrating perchlorate. It discusses: 1) Background on perchlorate contamination issues and calixarenes as potential extraction reagents. 2) The objectives to synthesize and characterize calix[4]arene-based polymeric materials and apply them to remove perchlorate from water. 3) Experimental methods including synthesis, characterization techniques, and column studies to test perchlorate removal efficiency.

1. 1

2. 2
Asif Ali Bhatti
Supervisors
Dr. Shahabuddin Memon & Dr. Najma Memon
Synthesis of Macrocyclic Chelating
Agents for the Removal and
Preconcentration of Perchlorate

3. 3
Background
Objectives
Experimental
Results and Discussion
Conclusion
Future Plan
Outlines

4. 4
The environment constituent essential life support
system on which we depend.
The chemicals used for industrial processes often create
dangerous forms of waste.
The amount of these chemicals has risen heavily in the
past, as more areas of the world are being industrialized
and new products are produced.
Background of Study

5. 5
Perchlorate
Anion consisting of tetrahedral array
of four oxygens around a chlorine
atom.
Typically found in the form of
perchloric acid and salts such as
ammonium perchlorate.
Perchlorate salts are highly soluble
in water. It migrates to groundwater
through leaching.
It is stable in water for years.

6. 6
Rocket Fuel
Fireworks
High explosives
Flares
Herbicides
Automobile airbags
Detergents
Uses of Perchlorate

7. 7
It acts as a competitive inhibitor of iodide
uptake by the NIS [sodium (Na+) iodide (I-)
symporter (S)] in humans.
Perchlorate can disrupt the production of thyroid
hormones and thus disrupt metabolism.
EPA considers the inhibition of
iodide uptake as the critical effect.
Health Hazards

8. 8
The chemical was placed on the EPA Office of
Water's Contaminant Candidate List (CCL) in
1998.
In 2002, the EPA recommended a maximum
containment level (MCL) for perchlorate of 1 ppb
in drinking water
Guidelines

9. 9
Brine Treatment
Biological Reduction Process
Membrane/Filtration Technologies
Biologically Active Carbon
Reverse Osmosis
Ion Exchange Resins
Remediation Technology

10. 10
In recent years, much attention has been paid to chemical
separation techniques and the design and synthesis of new
extraction reagents for ions and molecules. This attention results
from environmental concerns and efforts to save energy and
enhance recycling at the industrial level.
Among synthetically available materials, macrocyclic oligomers
containing phenolic rings well known as calixarenes have
generated significant interest in the field of host–guest chemistry
as trapping agents for ionic as well as neutral species.
Immobilization of calixarene framework onto a particular resin
not only reduce their solubility but at the same time makes them
efficient for the remediation of industrial undesired molecules

11. 11
 However, it has been planned to synthesize and immobilize
various modified calixarenes onto the polymeric supports in order
to enhance their thermal and extraction properties from organic as
well as aqueous media.
 It has also been planned to synthesize such type of material which
should be regenerated and can be used in multi-disciplines, such
as analytical and industrial fields.
 The “Supramolecular Chemistry” has provided a much better
solution to the search for molecular structures that can serve as
building blocks for producing sophisticated molecules by
anchoring functional groups oriented in such a way that they
delineate a suitable binding site for the recognition of harmful
and toxic species (ions or neutral molecules).

12. 12
This was achieved with the development of macrocyclic molecules such as
synthetic crown ethers, cyclophanes, and cyclodextrins etc.
A relatively new class of synthetic macrocyclic building blocks has recently
been emerged:
“The Calixarenes”

13. 13
Calixarenes

14. 14
Members
OH O
H
O
H
O
H
O
H
OH
OH
OH
t-but
t-but
t-but
t-but
t-but
t-but
t-but
t-but
OH
OH
OH
t-but
t-but
t-but
O
H
O
H
OH
t-but
t-but
t-but
OH
OH
t-but
t-but O
H
OH
t-but
t-but
p-tert-Butylcalix[4]arene p-tert-Butylcalix[6]arene p-tert-Butylcalix[8]arene

15. 15
Synthesis and characterization of
calix[4]arene based polymeric materials.
Application of synthesized calix[4]arene
based polymeric materials for the removal
and preconcentration of perchlorate from
water, soil and complex matrices.
Objectives

16. 16
1. Synthesis and characterization of
Calix[4]arene based polymeric
materials.
2. Application of synthesized Calix[4]arene
based polymeric materials for the
removal of perchlorate.
Experimental

17. 17

18. 18
M.Yilmaz et al. Journal of Macromolecular Science, Part A: Pure and Applied Chemistry, (2006), 43, 477–486.
Scheme 1
O
H
O
H
O
H
OH
OH
O
H
O
H
O
H
OH
O
H
O
H
O
H
OH
CH2
N CH2
N
CH2
N
CH2
N
O
H
O
H
O
H
O
CH2
N CH2
N
CH2
N
CH2
N
CH2
CH CH2
1 2
3
4
i ii
iii
iv
n
i. HCHO/NaOH ii.C6H6O/AlCl3 iii. C6H10N/HCHO. Iv NaH/Merrifield Resin

19. 19
Elemental Analysis
FT-IR Spectroscopy
Scanning Electron Microscopy (SEM)
Characterization

20. 20
OH
OH
O
H
OH
CH2
N CH2
N
CH2
N
CH2
N
3
Elemental Analysis
C52H68N4O4
Elements Calc: Exp:
% of N 6.89 6.59
% of C 76.81 81.45
% of H 8.43 8.715

21. 21
FT-IR Spectra
OH
OH
O
H
OH
CH2
N
CH2
N
CH2
N
CH2
N
3
5,11,17,23-Tetrakis(N-piperidinomethyl)-25,26,27,28-tetrahydroxycalix[4]arene

22. 22
A B
SEM
Before After

24. 24
The column sorption technique is more efficient
than batch sorption because of systematic
surface contact between sorbate and sorbent.
It can be kept in continual operation for long time.
It has large scale industrial application in various
engineering processes.
Column Study

25. 25
Height: 60 cm
Diameter: 8 mm
Flow Rate: 2 ml/min
Bed heights : 3.5 mm
: 4.5 mm
: 5.7 mm
Effluent
Bed
Glass Wool
Column Parameters

26. 26
Ion Chromatography
Sensitivity
Selectivity
Simultaneous Determination
Stability of Separator
Perchlorate Determination

27. Results and Discussion

28. 28
R
2
= 0.9699
0
5
10
15
20
25
0 1 2 3 4 5 6
Conc. (ppm)
Peak
Area
(
uS/cm*sec
)
Concentration range: 0.05 ppm - 5 ppm
Calibration Curve

29. 29
2ml/min, 5 ppm Perchlorate
50
55
60
65
70
75
80
85
90
95
100
0 1 2 3 4 5 6 7 8
pH
%Sorption
pH Effect

30. 30
Breakthrough curve can be defined as “ it is a
plot of concentration measured at fixed point in
column versus time”
It gives insight picture of the column sorption
process i.e. column exhaustion or equilibrium of
sorption etc.
Breakthrough Curve

31. 31
0
0.5
1
1.5
2
2.5
3
3.5
0 5 10 15 20 25 30 35 40
Time (min)
Ceff/Co
3mg
5mg
7mg
Theoritical 3mg
Breakthrough Curve

32. 32
Q
(Lmin-1)
Ƭ
(min)
Co
(mgL-1)
qo
(mg/g)
0.002
13.8 5 0.14
20.5 5 0.21
26.0 5 0.26
Adsorption Capacity

 Q
C
Q
C
q o
o
o 
 )
2
(
2
1

33. 33
Hutchins originally developed this model based
on the physically measuring the capacity of the
bed at different breakthrough values.
The rate of adsorption is controlled by the
surface reaction between adsorbate and the
unused capacity of the adsorbent.
Adsorbate is adsorbed only on the surface of the
adsorbent.
Bed Depth Service Time (BDST) Model

34. 34
• C = Effluent Concentration (mg/L)
• Co = Initial Concentration (mg/L)
• No = Adsorption Capacity (mg/L)
• K = Rate Constant (L/mg.min)
• X = Bed Depth (mm)
• t = Service time (min)
• V = Flow Rate (ml/min)
t
KC
V
X
KN
C
C
C
o
o
o










ln

35. 35
y = 4.533x - 0.7005
R
2
= 0.9973
0
5
10
15
20
25
30
3 3.5 4 4.5 5 5.5 6
Bed Heights
Service
Time

36. 36
BDST Parameters
No
(mgL-1)
K
(L.mg-1.min-1)
R2
55.13 0.054 0.99

37. 37
Single Component analysis.
YN
ln k
t
k
C
C
C
YN
o




kYN = Rate constant (Lmin-
1)
 = Time required for 50% breakthrough (min)
t = breakthrough time (min)
Yoon-Nelson Model

38. 38
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
0 10 20 30 40 50
Time (min)
ln(C/Co-C)
3 mg
5 mg
7 mg
Theoritical
Concentration: 5 ppm, Flow Rate: 2mL/min

39. 39
X
(mm)
kYN
(min-1)
τ
(min)
R2
3.5 0.09 5.07 0.87
4.5 0.07 11.24 0.95
5.7 0.06 29.20 0.96
Yoon-Nelson Model Parameters

40. 40
Results achieved from present study reveals
that calix[4]arene based resin possess high
efficiency for the removal of perchlorate from
water.
The models used for mechanism of sorption best
fit the experimental data.
The study will find its applicability in the field of
material, analytical, and environmental sciences
Conclusion

41. 41
Synthesis and characterization of calix[4]arene
based resins that are selective for perchlorate, in
this regard two schemes are under process of
synthesis in our synthetic labs.
The study will be extended to evaluate the
efficacy of the resins toward the real samples of
drinking water through preconcentration.
Future Plan

42. 42
 It has been proposed that new convenient methods will
be developed to synthesize the novel polymeric calixarene
compounds.
 The synthesized compounds will be characterized by
applying different analytical techniques, for instance,
chromatographic techniques, FTIR, NMR, MALDI-MS
and elemental analysis.
 For analytical applications of synthesized compounds, it
has been planned to use them in the field of separation
science and their properties will be explored with the help
of UV-Visible spectrophotometer, FTIR, DSC, TGA and
AAS.
Future plan

43. 43
OH
OH
O
H
OH
OH
OH O
OH
NO2
NO2
OR
OR
O
OH
NH2
OR
OR
O
OH
NO2
Br
N
H
OR
OR
O
OH
O
N
H
OR
OR
O
OH
O
n
m
O
Cl
1 2
3
4
Acetonitrile
Acetone/ K2CO3
Ethyl acetate/Methanol
Raney-Ni/N2H4 H2O
.
(i) BrCH2COOC2H5
(ii) R-NH2
Toluene/Methanol
R = CH2CONH(CH2)3N(CH2CH2CH3)2
5
6
CH2=CH-C Pyridine
CHCl3
Toluene
AIBN / styrene
/
R = CH2CONH(CH2)3N(CH2CH2CH3)2

44. 44

45. 45