COMMUNICATIONS
P. Selvam et al.
catalyst generated after recycling. Furthermore, the tered residue was then activated at 373 K for 6 h, and the acti-
vated catalyst was used for the recycling studies. Furthermore,
mesoporous nature of the reused catalyst was also con-
the reaction was carried out with the filtrate solution so as to
firmed by nitrogen sorption measurements (B±T sur-
2
À1
3
À1
check the leachability of the active metal ions from the matrix.
In addition, quenching studies were also performed with the fil-
trate obtained under the reaction (hot) conditions.
face area¼890 m g , pore volume¼0.45 cm g ,
and pore size¼26 ä). Thus, the catalyst behaves truly
as a heterogeneous solid acid catalyst by keeping its
structural integrity.
In conclusion, for the first time, a mesoporous mo-
lecular sieve is proposed for the chemoselective reduc-
Product Isolation
tion of a variety of a,b-unsaturated carbonyls having im- In a typical isolation procedure, after the reaction is completed,
the reaction mixture was filtered out and the filtrate was wash-
portance for fine chemicals and drugs. The catalyst,
ed several times with distilled water in order to remove the
CoHMA, was found to be highly selective for this pur-
base, which resulted in the formation of an emulsion. The crude
pose and yields only unsaturated alcohols with 100% se-
product was extracted from this emulsion with CH Cl , dried
2
2
lectivity. The yield and reaction time are highly encour-
aging. The catalyst was found to be heterogeneous in na-
ture for this reaction.
over anhydrous Na SO , and the excess solvent was removed
2
4
under reduced pressure. This was further subjected to column
chromatography to isolate the pure products.
Experimental Section
References
CoHMA Catalyst Preparation
[1] M. Bartok, A. Molnar, The Chemistry of Double-bonded
Functional Groups, S. Patai (±d.), Wiley, New York,
Cobalt(II) substituted hexagonal mesoporous aluminophos-
phate (CoHMA) molecular sieve catalyst was prepared as
per the following procedure. Phosphoric acid was first diluted
with water and then aluminium isopropoxide was added under
vigorous stirring followed by the addition of cobalt acetate sol-
ution. The mixture was kept under constant stirring at 343 K
for 1 h and then tetramethylammonium hydroxide (TMAOH;
1
997, pp. 844.
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[
[
5] R. W. Johnstone, A. H. Wilbey, I. D. ±ntwistle, Chem.
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Catal. 1990, 58, L5.
25 wt % in water) was added drop-wise. The slurry was kept
under stirring for a few hours. Then cetyltrimethylammonium
chloride (CTAC; 25% in water) was added drop-wise and stir-
red for another 12 h. The pH was maintained at 10 with a final
molar gel composition of: 0.96 Al O :P O :0.08 CoO:0.5
[7] G. Szollosi, M. Bartok, J. Mol. Catal. A 1999, 148, 265.
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2
3
2
5
(
CTA) O:1.25 (TMA) O:70 H O ([AlþP]/Co¼50). It was
2
2
2
then transferred into a Teflon-lined autoclave and heated for
crystallization at 373 K for 72 h. The resultant solid product
was washed repeatedly with distilled water, filtered and dried
at 343 K for 12 h. The as-synthesized samples were then cal-
[
cined at 823 K for 1 h under flowing N , followed by 2 h in O .
2
2
[
12] P. Gallezot, Handbook of Heterogeneous Catalysis, Wi-
ley, New York, 1997, Vol. 5, p. 2209.
CTH Reaction Procedure
[13] C. F. Graauw, J. A. Peters, H. van Bekkum, J. Huskens,
Synthesis 1994, 1007.
In a typical CTH reaction procedure, the substrate (20 mmol)
and KOH pellets (20 mmol) dissolved in 20 mL of 2-propanol
[
14] F. Quignard, O. Graziani, A. Choplin, Appl. Catal. A
999, 182, 29.
1
(
20 mL) were stirred in the presence of 100 mg of the catalyst.
[
[
15] T. L. Ho, G. A. Olah, Synthesis 1977, 169.
16] J. C. van der Waal, P. J. Kunkeler, K. Ta, H. van Bekkum,
J. Catal. 1998, 173, 74.
[17] ±. J. Creyghton, R. S. Downing, J. Mol. Catal. A 1998,
134, 47.
The mixture was then refluxed at 356 K for 2±6 h depending
upon the substrate. The resulting products were analyzed using
a gas chromatograph (±shika) fitted with an OV-101 column.
In order to check the reusability of the catalyst, the filtered cat-
alyst was washed with acetone for several times followed by
washing with water to remove alkali, if any present. The fil-
[18] G. Zassinovich, G. Mestroni, Chem. Rev. 1992, 92, 1051.
544
¹ 2004 WIL±Y-VCH Verlag GmbH & Co. KGaA, Weinheim
asc.wiley-vch.de
Adv. Synth. Catal. 2004, 346, 542±544