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Catalysis Science & Technology
Page 8 of 10
DOI: 10.1039/C5CY01034A
ARTICLE
Journal Name
3.3.3
Preparation of Cs-g-PCPA
chelate: Fe / Cs-g-PCPA
–
supported Iron(III) heterogeneous catalysts for Michael addition reactions. The
results of this study show that Cs-g-PCPA (G = 64%) serves as a
superior catalyst for Michael additions as compared to
An aqueous solution containing Fe(NO3)3 was used to absorb
Fe(III) ions on the surface of Cs-g-PCPA grafted chitosan beads
of 64 %G.20,21 The degree of adsorption was calculated based
on the difference of Fe3+ concentration in aqueous solution
before and after adsorption at wavelength 248 nm. For Fe(III)
adsorption onto Cs-g-PCPA, a contact time of 5 h at pH 1.8 was
used for stirred mixture of Cs-g-PCPA beads (0.05 g) and 100
mL (10 mM) of Fe(NO3)3 solution in 250 mL beaker. The
amount adsorbed on the beads was calculated according to
the following equation:
chitosan itself and suggest that the new basic catalyst can
replace other more toxic old organic catalysts, like piperidine
and pyridine, in Michael additions. The chitosan graft cross-
linked copolymer Cs-g-PCPA was found to have higher thermal
stability than chitosan and, as a result, it can be used
effectively for higher temperature reactions. Finally, the iron
(III)-supported chitosan copolymer complex, Cs-g-PCPA (G =
64%)/Fe (III), was shown to be a promising catalyst for
selective methyl group oxidation reactions of methyl
substituted heterocycles.
( C0 - Ce ) V
Adsorption Capacity (qe)
=
W
Acknowledgements
Where C0 is the initial Fe(III) concentration (ppm), Ce is the
final concentration of Fe(III) after the adsorption time, V is the
volume of Fe(III) solution (mL) and W is the used weight of
graft copolymer Cs-g-PCPA beads (g). The yellowish-coloured
beads containing adsorbed Fe3+ were washed thoroughly with
distilled water and stored in the distilled water for further use.
Under the previous conditions, the maximum adsorption
capacity was obtained as 0.091 mmol Fe3+/g chitosan.
The authors wish to acknowledge financial support provided
by the Kuwait University. They also their appreciation for
technical support from the E.M unit and the general facilities
projects GS01/01, GS01/03, GS01/05, GS03/01, GS 03/08
under the GFS program. Also, the authors would like to thank
the Nanoscopy Science Center at Kuwait University.
Notes and references
1. Brundtland, Our common future, "Our common future:
The World Commission on Environment and
Development", Oxford: Oxford University Press, 1987.
3.3.4
Conversion of catalyst powder to the form of spherical
beads
2. A. S. Bommarius, B. R. Riebel, Biocatalysis:
Fundamentals and Applications,Wiley-VCH, Verlag
GmBH & KGaA: Weinheim (Germany), 624 pp, 2004.
Chitosan (or modified chitosan) was converted to spherical
bead shapes as previously reported35 by dissolving 2.00 g of
powder in 60 mL of 5% (v/v) acetic acid solution. The viscous
solution was sprayed into 500 mL of a stirred 0.50 M NaOH
solution as a precipitation bath. In the bath neutralization of
the acetic acid occurred within the chitosan gel and thereby
promoting coagulation to form spherical uniform chitosan gel
beads. Impurities trapped in the pores of chitosan beads were
removed by rinsing with distilled water. Filtration and air-
drying gave beads that could be stored under distilled water.
3. J. Clark, D. Macquarrie, Handbook of Green Chemistry
and Technology, Blackwell Science Ltd., (Eds),
Abingdon, Oxford, UK, 2002.
4. P. T. Anastas, J. C. Warner, Green Chemistry: Theory
and Practice, Oxford University Press., New York, p. 30,
1998.
5. D. Warren, Green Chemistry. A Teaching Resource.
Royal Society of Chemistry, Cambridge, 2001.
6. R. H. Crabtree, Handbook of Green Chemistry – Green
Catalysis, Platinum Metals Re 54, 2010, 233.
7. G. Centi, S. Perathoner, Catal. Today, 2003, 77, 287.
8. S. K. Ritter, Chem. Eng. News, 2003, 81, 66.
Conclusions
In the investigation described above, we have shown that the
grafted chitosan, Cs-g-PCPA (G = 64%) beads were employed
as an efficient basic, recyclable, reusable, and green
9. J. E. Hardy, S. Hubert, D. J. Macquarrie, A. J. Wilson,
Green Chem., 2004, 6, 53.
8 | J. Name., 2012, 00, 1-3
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