Magnesium-Lanthanum Mixed Metal Oxide
COMMUNICATIONS
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onate at room temperature, and showing the ability to
work well in relatively concentrated solutions in tol-
uene. In the conditions used here the catalyst can be re-
cycled several times without any thermal treatment.
Since the preparation of this solid includes a calcination
at 923 K it could be regenerated at high temperature by
oxidation of deposited heavy organics in the case of a
possible contamination. This is not possible for organic
catalysts.
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kade, J. Org. Chem. 2002, 67, 3555–3560.
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Tetrahedron 2003, 59, 561–566.
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Experimental Section
Catalyst Characterization
The solids were analysed by ICP after dissolution by acid at-
tack. The surface areas were determined from the isotherms
of adsorption of N2 at 77 K using the BET equation. X-Ray
powder diffraction patterns were recorded on a Phillips instru-
ment using CuKa1radiation. The isotherm for N2 adsorption at
77 K was determined on solids activated at 723 K in N2 or air,
then desorbed in situ at 473 K in vacuum. Basicities were char-
acterised by microcalorimetry using CO2 adsorption at 303 K
with a Tian-Calvet calorimeter on samples activated in vacuum
at 673 K.[27]
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G. Bergeret, R. Montiel, J. Lopez, F. Figueras, J. Catal.
2004, 221, 483–490.
[14] M. Zahouily, B. Bahlaouan, M. Aadil, A. Rayadh, S.
Sebti, Organic Process Research and Development
2004, 8, 275–278.
[15] M. Zahouily, Y. Abrouki, A. Rayadh, S. Sebti, H. Dhi-
mane, M. David, Tetrahedron Lett. 2003, 44, 2463–2465.
[16] B. M. Choudary, B. Kavita, N. S. Chowdari, B. Sreedhar,
M. L. Kantam, Catalysis Lett. 2002, 78, 373–377.
[17] B. M. Choudary, M. Lakshmi Kantam, B. Kavita, C. Ven-
kat Reddy, F. Figueras, Tetrahedron 2000, 56, 9357–9364.
[18] A. Corma, S. Iborra, I. Rodriguez, M. Iglesias, F. San-
chez, Catalysis Lett. 2002, 82, 237–242.
[19] R. Ballini, P. Marziali, A. Mozzicafreddo, J. Org. Chem.
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[20] B. Veldurthy, F. Figueras, Chem. Commun. 2004, 10,
734–735.
[21] A. Corma, V. Fornes, R. M. Martin-Aranda, H. Garcia, J.
Primo, Appl. Catal. 1990, 59, 237–248.
Catalytic Tests
The reactions were performed at room temperature in differ-
ent solvents, using typically 2 mmol of each reactant and
4 mL of solvent with 0.1 g of solid catalyst calcined at 773 K.
The products were separated at the end of the reaction and
characterised by NMR and GC-MS. The reaction usually gives
a single product, with no other side reaction such as Knoevena-
gel condensation. The conversion was estimated from the
changes in the amount of substrate.
[22] F. G. Bordwell, Acc. Chem. Res. 1988, 21, 456–463.
[23] J. Sanchez-Valente, F. Figueras, M. Gravelle, P. Kumbhar,
J. Lopez, J.-P. Besse, J. Catal. 2000, 189, 370–381.
[24] H. Kabashima, H. Tsuji, T. Shibuya, H. Hattori, J. Mol.
Catal. A: Chem. 2000, 155, 23–29.
Acknowledgements
Thanks are due to the technical services of IRC for their help in
catalyst characterization.
[25] M. J. Climent, A. Corma, S. Iborra, A. Velty, J.Mol. Cat-
al. A: Chem. 2002, 182–183, 327–342.
[26] J. Lopez, R. Jacquot, F. Figueras, Stud. Surf. Sci. Catal.
2000, 130A, 491–496.
[27] P. C. Gravelle, Adv. Catal. 1972, 22, 191.
[28] B. M. Choudary, M. Lakshmi Kantam, C. R. Venkat
Reddy, K. Koteswara Rao, F. Figueras, J. Mol. Catal. A:
Chem. 1999, 146, 279–284.
[29] B. M. Choudary, M. Lakshmi Kantam, V. Neeraja, K.
Koteswara Rao, F. Figueras, L. Delmotte, Green Chem.
2001, 3, 257–260.
[30] J.-M. Clacens, D. Genuit, B. Veldurthy, G. Bergeret, L.
Delmotte, A. Garcia-Ruiz, F. Figueras, Appl. Catal. B:
Environmental 2004, 53, 95–100.
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