Porous hierarchical magnesium oxide-based heterogeneous catalyst for the Knoevenagel condensation

Article abstract of DOI:10.1134/S1070363217050310

Herein, an operationally facile and efficient Knoevenagel reaction catalyzed by porous hierarchical MgO/Mg(OH)₂ is presented. Condensation of various aldehydes with malononitrile proceeds under mild conditions and gives the target products with

Full text of DOI:10.1134/S1070363217050310

ISSN 1070-3632, Russian Journal of General Chemistry, 2017, Vol. 87, No. 5, pp. 1085–1086. © Pleiades Publishing, Ltd., 2017.
Porous Hierarchical Magnesium Oxide-Based Heterogeneous
Catalyst for the Knoevenagel Condensation1
K. Deilami and S. Sayyahi*
Department of Chemistry, Mahshahr Branch, Islamic Azad University, Mahshahr, Iran
*e-mail: sayyahi.soheil@gmail.com
Received April 1, 2017
Abstract—Herein, an operationally facile and efficient Knoevenagel reaction catalyzed by porous hierarchical
MgO/Mg(OH)2 is presented. Condensation of various aldehydes with malononitrile proceeds under mild
conditions and gives the target products with high yields.
Keywords: porous hierarchical metal oxide, heterogeneous catalyst, Knoevenagel condensation, aqueous medium
DOI: 10.1134/S1070363217050310
INTRODUCTION
through a solution of MgO (200 mL, 16 g/L) for
45 min. Upon addition of EtOH (100 mL) the mixture
was stirred vigorously at 80°C for 5 min after which
the solution was stored at 80°C for 2 h. Upon cooling
down to room temperature, the precipitated solid was
filtered off, washed with water (10 mL) and EtOH
(3×10 mL) and dried under reduced pressure to give
PHMgO/Mg(OH)2.
Magnesium oxide and hydroxide as heterogeneous
basic catalysts or solid-supported catalysts have been
widely used in organic synthesis [1–5] due to their
specific stoichiometry, redox properties, acid/base
character, and crystalline and electronic structures. Method
and conditions of their preparation are important
factors affecting their surface and catalytic properties [6].
Characteristics of the produced catalyst demon-
strated a good match with the earlier reported ones. FT–
IR spectrum, ν, cm–1: the bands at ~3700 (sharp),
~3422 (broad), ~1430, and ~1000–500 could be
attributed to free O–H, H-bonded O–H, pre-adsorbed
CO2 at room temperature on MgO and overtone of a
fundamental lattice vibration of Mg–O stretching [9],
respectively. The SEM image indicated spongy shapes
with irregular pores of the synthesized catalyst. The
XRD pattern recorded of the as-prepared catalyst
displayed highest intensity at 2θ = 18.34°, 30.27°,
38.56°, 59.08°, and 37.77°, 42.90°, 61.76°, in the
region of 0°–80° that corresponded to Mg(OH)2 and
MgO phases, respectively [10].
In 2013 Tian and co-workers [7] reported synthesis
of porous hierarchical MgO (PHMgO) with high
specific surface area.
The Knoevenagel condensation in water under
heterogeneous catalysis has attracted close attention
due to its environmentally clean and benign character
[8]. Based on the above, we studied the catalytic
activity of PHMgO/Mg(OH)2 in the Knoevenagel
condensation in water medium (see the figure).
EXPERIMENTAL
The materials were purchased from Sigma-Aldrich
and Merck and used without further purification. All
reactions were monitored by TLC on aluminum-
backed silica gel 60 F254 plates (0.2 mm thickness,
Merck). Scanning electron microscopy (SEM) analyses
was carried out on a Philips XL30 instrument. FT-IR
spectra were recorded on a BOMEM MB-Series spec-
trophotometer using KBr pellets. The products were
identified and characterized by comparison of their
physico-chemical characteristics with those reported earlier.
RESULTS AND DISCUSSION
The catalytic performance of PHMgO/Mg(OH)2 in
the Knoevenagel reaction was tested by condensation
of 4-nitrobenzaldehyde with malononitrile under
different conditions (see the table, entry 5). Treatment
of the reactants in the presence of 0.1 g of the catalyst
in water at 60°C led to the best results. Following
study of the reaction was extended to a range of benzal-
dehydes and heterocyclic aldehydes under the same
conditions (see the table). Aldehydes with both
electron-withdrawing and -donating functional groups
Preparation of MgO/Mg(OH)2. In accordance with
the known procedure, CO2 was passed (200 mL/min)
1 The text was submitted by the authors in English.
1085

1086
DEILAMI, SAYYAHI
(b)
(a)
200 nm
1 μm
Fig. 1. SEM images of the porous hierarchical (a) MgO and (b) Mg(OH)2.
underwent the catalyzed condensation efficiently with
good to excellent yields (see the table). Finally, we
investigate reusability of the catalyst. The catalyst,
PHMgO/Mg(OH)2, was extracted from the filtrate by
hot ethanol and used in the same process for not less
than four times without any loss of it activity.
CONCLUSIONS
The efficient magnesium-based catalytic system for
the Knoevenagel condensation of malononitrile with
aldehydes under environmentally friendly conditions is
developed. The catalyst can be readily recovered and
used repeatedly in the same process without loss of its
activity.
ACKNOWLEDGMENTS
Yield of the Knoevenagel condensation catalyzed by
PHMgO/Mg(OH)2
a
This work was supported by the Mahshahr Branch,
Islamic Azad University. Also, the authors acknowledge
Fanavaran Petrochemical Company for their corporation.
H
CN
CN
CN
CN
PHMgO/Mg(OH)2 (0.1 g)
+
O
H2O, 60°C, 5 min
Ar
Ar
REFERENCES
Entry
no.
Ar
Isolated yield, %
1. Jia, C.-J., Liu, Y., Bongard, H., and Schüth, F., J. Am.
Chem. Soc., 2010, vol. 132(5), p. 1520. doi 10.1021/
ja909351e
2. Seifi, M. and Sheibani, H., Catal. Lett., 2008, vol. 126(3),
p. 275. doi 10.1007/s10562-008-9603-5
3. Karmakar, B., Nayak, A., and Banerji, J., Tetrahedron
Lett., 2012, vol. 53(37), p. 5004. doi 10.1016/
j.tetlet.2012.07.030
4. Pagadala, R., Maddila, S., Moodley, V., van Zyl, W.E.,
and Jonnalagadda, S.B., Tetrahedron Lett., 2014,
vol. 55(29), p. 4006. doi 10.1016/j.tetlet.2014.05.089
5. Di Cosimo, J.I., Diez, V.K., Ferretti, C., and
Apesteguia, C.R., Catalysis, 2014, vol. 26, p. 1. doi
10.1039/9781782620037-00001
6. Julkapli Nurhidayatullaili, M. and Bagheri, S., Rev.
Inorg. Chem., 2016, vol. 36, p. 1. doi 10.1515/revic-
2015-0010
7. Tian, P., Han, X.-Y., Ning, G.-L., Fang, H.-X., Ye, J.-W.,
Gong, W.-T., and Lin, Y., ACS, 2013, vol. 5(23),
p. 12411. doi 10.1021/am403352y
8. Bigi, F. and Quarantelli, C., Curr. Org. Synth., 2012,
vol. 9(1), p. 31. doi 10.2174/157017912798889198
9. Puriwat, J., Chaitree, W., Suriye, K., Dokjampa, S.,
Praserthdam, P., and Panpranot, J., Catal. Commun.,
2010, vol. 12(2), p. 80. doi 10.1016/j.catcom.2010.08.015
10. Ding, Y., Zhang, G., Wu, H., Hai, B., Wang, L., and
Qian, Y., Chem. Mater., 2001, vol. 13(2), p. 435. doi
10.1021/cm000607e
1
2
C6H5
91
4-ClC6H4
92
3
4-BrC6H4
92
4
4-FC6H4
90
5
4-NO2C6H4
3-NO2C6H4
4-MeC6H4
2,4-Cl2C6H3
2-ClC6H4
12b, 30c, 65d, 91
6
93
81
89
79
75
90
94
86
80e
83
7
8
9
10
11
12
13
14
15
4-(CH3)2NC6H4
3-Furyl
4-PropylC6H4
4-MeOC6H4
3-Indolyl
4-OHC6H4
a
Reaction conditions: a mixture of aldehyde (1.0 mmol),
malononitrile (1.0 mmol), water (3.0 mL) and the catalyst (0.1 g)
was stirred at 60°C for 5 min. b Without catalyst. c Room
temperature. d 0.05 g catalyst, e Conversion, %.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 87 No. 5 2017