384
BRAHMKHATRI, PATEL
Table 3. Main characteristics of TPA3/SiO2 and TPA3/ZrO2
Thermal stability
(TGA), °C
Catalyst
IEC, meq/g
Surface area, m2/g Yield of butyl acetate, %
TON
TPA3/SiO2
TPA3/ZrO2
500
430
0.62
0.62
234
146
71
53
3545
2650
4. Yang, L., Qi, Y., Yuan, X., et al., J. Mol. Catal. A: Chem.
2005, vol. 229, p. 199.
5. Shanmugam, S., Viswanathan, B., and Varadarajan, T.K.,
J. Mol. Catal. A: Chem., 2004, vol. 223, p. 143.
6. Pizzio, L.R., Vázquez, P.G., Cáceres, C.V., and
Blanco, M.N., Appl. Catal., A, 2003, vol. 256, p. 125.
7. Janik, M.J., Davis, R.J., and Neurock, M., J. Catal.
2006, vol. 244, p. 65.
8. Kamiya, Y., Ooka, Y., Obara, C., et al., J. Mol. Catal. A:
Chem., 2007, vol. 262, p. 77.
,
catalyst than TPA3/ZrO2 since higher TON are
expected for more efficient catalyst.
Surface area of catalyst also plays an important role
in catalytic reactions. The surface area of SiO2 is
higher than that of ZrO2. Increase in surface area may
be due to the nature of support. The higher value of
surface area for TPA3/SiO2 as compared to that of
TPA3/ZrO2 is also responsible for higher catalytic
activity.
,
Thermal stability of the catalyst at higher temperaꢀ
ture decides its applicability in extreme conditions.
The thermal stability of TPA increases from
TPA3/ZrO2 to TPA3/SiO2 as observed from TGA and
DSC results. This increased thermal stability of TPA
on SiO2 could be explained due to the nature of supꢀ
port.
9. Pizzio, L.R., Vázquez, P.G., Cáceres, C.V., et al., Appl.
Catal., A, 2005, vol. 287, p. 1.
10. Nandhini, K.U., Arabindoo, B., Palanichamy, M., and
Murugesan, V., J. Mol. Catal. A: Chem., 2004, vol. 223,
p. 201.
11. Yadav, G.D. and Doshi, N.S., J. Mol. Catal. A: Chem.
2003, vol. 194, p. 195.
,
Thermal study shows that the TPA keeps its Keggin 12. Mao, J., Kamiya, Y., and Okuhara, T., Appl. Catal., A
2003, vol. 255, p. 337.
SiO2. The present catalyst is proved to be successful in 13. Sarsani, V.R., Lyon, C.J., Hutchenson, K.W., et al.,
J. Catal., 2007, vol. 245, p. 184.
tions as compared with the traditional liquid acid catꢀ 14. Yadav, G.D. and Bhagat, R.D., J. Mol. Catal. A: Chem.
2005, vol. 235, p. 98.
,
structure undegraded up to 500°C when supported on
esterification of primary alcohols under mild condiꢀ
alyst. The TPA3/SiO2 was found to be more active as
,
compared to TPA3/ZrO2. The difference in the cataꢀ 15. Cardoso, L.A.M., Alves, W., Gonzaga, A.R.E., et al.,
J. Mol. Catal. A: Chem., 2004, vol. 209, p. 189.
lytic activity may be due to the more acidic nature of
SiO2 than ZrO2.
16. Castro, C.D., Primo, J., and Corma, A., J. Mol. Catal.
A: Chem., 1998, vol. 134, p. 215.
17. Sharma, P. and Patel, A., Bull. Mater. Sci., 2006,
ACKNOWLEDGMENTS
vol. 29, p. 439.
18. Bhatt, N., Shah, C., and Patel, A., Catal. Lett., 2007,
vol. 117, p. 146.
19. Bhatt, N. and Patel, A., Catal. Lett., 2007, vol. 113,
One of the authors, Ms. Varsha Brahmkhatri, is
thankful to BRNS (Project no. 2007/37/20/
BRNS/917, Mumbai) for the financial assistance.
p. 99.
20. Patel, S., Purohit, N., and Patel, A., J. Mol. Catal.
2003, vol. 192, p. 195.
21. Misono, M., Mizuno, N., Katamura, K., et al., Bull.
Chem. Jpn., 1985, vol. 55, p. 400.
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Catal. A: Chem., 2000, vol. 161, p. 223.
,
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2010