Journal of Materials Chemistry A
Paper
continues toward the formation of terephthalic acid as shown
below.
5 B. Saha and J. H. Espenson, J. Mol. Catal. A: Chem., 2007, 271,
1–5.
6
B. Saha and J. H. Espenson, J. Mol. Catal. A: Chem., 2005, 241,
3–38.
W. P. Schammel, V. Adamian, S. P. Brugge, W. H. Gong,
P. D. Metelski, P. O. Nubel and C. Zhou, International
Patent WO 133978 A2, 2007.
III
+
Ce(IV) + 2PhCH
3
/ 2Ce –PhCH
3
_ initiation step
O _+ H
(ii)
3
7
III
Ce –PhCH
+
3
2
_ + O / Ce(IV) + 2PhCH
2
2
2
O
(iii)
PhCH O_ + PhCH / PhCH OH + PhCH _ propagation (iv)
2
3
2
2
8
9
B. Saha, N. Koshino and J. H. Espenson, J. Phys. Chem. A,
2
004, 108, 425–531.
B. Saha and J. H. Espenson, J. Mol. Catal. A: Chem., 2004, 207,
23–129.
PhCH
2
_ + O
2
/ PhCH
2
OO_ propagation
(v)
1
2
PhCH OO_ / PhCH OH + PhCHO + O termination (vi)
2 2 2
10 S. A. Chavan, D. Srinivas and P. Ratnasamy, J. Catal., 2001,
Thus, the exposed ceria helped to form the free radical
204, 409–419.
rapidly from para-xylene by self reduction, which then reacts 11 J. M. Tibbitt, W. H. Gong, W. P. Schammel, R. P. Hepper,
with oxygen to nally form terephthalic acid.
V. Adamian, S. P. Brugge, P. D. Metelski and C. Zhou,
International Patent WO 2007/133976 A2, 2007.
2 P. A. T. Hamley, T. Ilkenhans, J. M. Webster, E. Garcia-
Verdugo, E. Venardou, M. J. Clarke, R. Auerbach,
W. B. Thomas, K. Whiston and M. Poliakoff, Green Chem.,
2002, 4, 235–238.
1
Conclusion
We have developed a novel heterogeneous catalyst for aqueous
phase oxidation of para-xylene to bypass all the hazardous steps
involved during the production of industrially important ter- 13 S. Chowdhury and K.-S. Lin, J. Nanomater., 2011, 2011, 1–16.
ephthalic acid. We have synthesized surface active and (111) 14 L. Vivier and D. Duprez, ChemSusChem, 2010, 3, 654–678.
and (100) surface exposed CeO
surface area. The particle size of the monodispersed single
2
nanocrystallite with very high 15 C. Sun, H. Li and L. Chen, Energy Environ. Sci., 2012, 5, 8475–
8505.
crystalline particle is 15 nm. XRD and HRTEM analyses conrm 16 C. Kleinlogel and L. Gauckler, Adv. Mater., 2001, 13, 1081–1085.
the cubic uorite structure of the ceria nanocrystals, which are 17 N. Izu, W. Shin, N. Murayarna and S. Kanzaki, Sens.
grown preferably in h111i and h100i directions due to the
presence of surfactants and high temperature, however, expo- 18 S. Rousseau, O. Marie, P. Bazin, M. Daturi, S. Verdier and
sure of (110) surface in few particles could not be ignored. The V. Harle, J. Am. Chem. Soc., 2010, 132, 10832–10841.
catalytic activity of CeO nanocrystals (present samples) was 19 M. V. Ganduglia-Pirovano, C. Popa, J. Sauer, H. Abbott,
Actuators, B, 2002, 87, 95–98.
2
investigated for the rst time for aerobic oxidation of para-
xylene to terephthalic acid in non-hazardous condition. The
A. Uhl, M. Baron, D. Stacchiola, O. Bondarchuk,
K. Shaikhutdinov and H.-J. Freund, J. Am. Chem. Soc.,
2010, 132, 2345–2349.
result shows the formation of 30–40% terephthalic acid under
ꢁ
mild reaction condition, i.e. at 70 C in water, by avoiding the 20 M. Jiang, N. O. Wood and R. Komanduri, Wear, 1998, 220,
corrosive bromide promoter and acetic acid solvent. The recy-
59–71.
cled catalyst again shows good conversion without the change 21 J. Lv, Y. Shen, L. Peng, X. Guo and W. Ding, Chem. Commun.,
of the uorite crystal structure, morphology and the particle
2010, 46, 5909–5911.
size of ceria.
22 J. Kaspar, P. Fornasiero and M. Graziani, Catal. Today, 1999,
50, 285–298.
2
3 R. Chockalingam, V. R. W. Amarakoon and H. Giesche,
J. Eur. Ceram. Soc., 2008, 28, 959–963.
Acknowledgements
KD is grateful to UGC, India and DG is grateful to CSIR, India for 24 H. Y. Kim, H. M. Lee and G. Henkelman, J. Am. Chem. Soc.,
research fellowship. SD thanks DST, India for nancial support
2012, 134, 1560–1570.
Grant SR/S1/IC-27/2011). BS thanks University of Delhi and 25 S. Carrettin, P. Concepcion, A. Corma, J. M. Lopez Nieto and
(
CSIR, India for nancial support. We thank Dr T. Ahmad for the
V. F. Puntes, Angew. Chem., Int. Ed., 2004, 43, 2538–2540.
help with BET measurements, IIT-Delhi for FESEM, M.Tech. 26 A. Bruix, J. A. Rodriguez, P. J. Ram ´ı rez, S. D. Senanayake,
NSNT centre and USIC, DU for XRD and HRTEM facility.
J. Evans, J. B. Park, D. Stacchiola, P. Liu, J. Hrbek and
F. Illas, J. Am. Chem. Soc., 2012, 134, 8968–8974.
7 D. C. Sayle, S. A. Maicaneanu and G. W. Watson, J. Am. Chem.
Soc., 2002, 124, 11429–11439.
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This journal is ª The Royal Society of Chemistry 2013