Zr-MCM-41 nanoreactors as efficient and reusable catalysts in the synthesis of new aminonitriles by the strecker reaction

Article abstract of DOI:10.1016/S1872-2067(10)60189-1

The synthesis and characterization of Zr-MCM-41 nanoreactors and their catalytic activity in the synthesis of new amino nitrile derivatives by the Strecker reaction in high yields and in short reaction times is reported.

Full text of DOI:10.1016/S1872-2067(10)60189-1

CHINESE JOURNAL OF CATALYSIS
Volume 32, Issue 4, 2011
Online English edition of the Chinese language journal
Cite this article as: Chin. J. Catal., 2011, 32: 532–535.
RESEARCH PAPER
Zr-MCM-41 Nanoreactors as Efficient and Reusable
Catalysts in the Synthesis of New Aminonitriles by the
Strecker Reaction
Zohreh DERIKVANDa, Fatemeh DERIKVANDb
Department of Chemistry, Faculty of Science, Islamic Azad University, Khorramabad Branch, Khorramabad, Iran
Abstract: The synthesis and characterization of Zr-MCM-41 nanoreactors and their catalytic activity in the synthesis of new amino nitrile
derivatives by the Strecker reaction in high yields and in short reaction times is reported.
Key words: Zr-MCM-41; Strecker reaction; aminonitrile; three component one-pot reaction
The three-component condensation of aldehydes, amines,
and trimethylsilyl cyanide (TMSCN) in the Strecker reaction is
an important reaction in organic synthesis. The products are
Į-aminonitrile derivatives, which are versatile intermediates
that can be transformed into a variety of building blocks such
as Į-amino acids, 1,2-diamines, and nitrogen-containing het-
erocycles [1]. A variety of acid catalysts have been used in this
reaction [2–8]. The tedious work-up procedure, long reaction
time, toxic catalysts, and the use of an inert atmosphere are
some of the drawbacks of these methods. For example,
Al-MCM-41 has been used under an argon atmosphere [8].
New green legislation requires a decrease in waste creation
and the use of more environmentally friendly alternative
catalysts, which makes the current homogeneous organic re-
actions environmentally unacceptable [9].
Zr-MCM-41, its characterization, and its catalytic activity in a
three-component one-pot synthesis of Į-aminonitrile deriva-
tives by condensing aldehydes, amines, and trimethylsilyl
cyanide.
1 Experimental
1.1 Preparation of Zr-MCM-41
Fumed silica (8 g) was added to a solution of sodium hy-
droxide (2 g) in distilled water (150 ml) in a baker at 80 °C. The
resulting mixture was continuously stirred until a clear solution
was obtained. Cethyltrimethyl ammonium bromide (CTAB, 3
g) was slowly added to this solution under vigorous stirring at
room temperature. The resulting gel was stirred for an addi-
tional 2 h. In the next stage zirconium (IV) oxide chloride
octahydrate (5 g) was dissolved in distilled water (100 ml) by
adding concentrated H2SO4 (2.5 ml) until a clear solution was
obtained. This solution was added to the resulting gel in a
dropwise manner over 2 h under vigorous stirring. The ob-
tained gel was transferred into a Teflon-lined stainless steel
autoclave for hydrothermal treatment at 100 °C over 3 d. The
resulting solid product was recovered after filtration and
washing several times with deionized water. The obtained
white solid was dried in air at 100 °C for 5 h. Finally, the
Considerable attention has been given to M41S (Mobil
Composition of Matter) mesoporous materials but particularly
the MCM-41 family because of their unique properties
[10–12]. They have high specific surface areas, high pore
volumes, and tunable pore sizes with a narrow distribution.
However, Si-based MCM-41 exhibits only mild acidity, which
is much weaker than that of the microporous zeolites [13]. The
incorporation of zirconium into the MCM-41 framework in-
creases both the Lewis and Brönsted acidity [13].
Herein, we report a new approach toward the synthesis of
Received 1 November 2010. Accepted 15 December 2010.
aCorresponding author. Tel/Fax: +98-661-6200399; E-mail: zderik@yahoo.com
bCorresponding author. Tel/Fax: +98-661-6200399; E-mail: f_derikvand@yahoo.com
Copyright © 2011, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier BV. All rights reserved.
DOI: 10.1016/S1872-2067(10)60189-1

Zohreh DERIKVAND et al. / Chinese Journal of Catalysis, 2011, 32: 532–535
1
sample was calcined at 600 °C for 16 h in air. The heating rate
zylamino)acetonitrile). H NMR (300 MHz, CDCl3): į 1.86
(2H, br. s, 2NH), 2.03 (6H, s, 2Me), 3.86 (4H, s, 2CH2), 6.92
(4H, d, J = 9 Hz, 4CHAr), 7.33 (4H, d, J = 9 Hz, 4CHAr), 7.60
(4H, s, 4CHAr). Mass: 395.3, 373.4. Anal. Calcd (%): C, 79.16;
H, 6.64; N, 14.20; Found: C, 78.76; H, 6.44; N, 14.50.
Compound 2: 2-(4-chlorophenyl)-2-(4-morpholinoph-
enylamino)acetonitrile. 1H NMR (300 MHz, CDCl3): į
3.06–3.09 (4H, m, 2CH2), 3.85–3.88 (4H, m, 2CH2), 5.36 (1H,
d, J = 9, CH), 6.77 (2H, d, J = 9 Hz, 2CHAr), 6.92 (2H, d, J = 9
Hz, 2CHAr), 7.44 (2H, d, J = 9 Hz, 2CHAr), 7.57 (2H, d, J = 9
Hz, 2CHAr).
was 1.5 °C/min and the molar ratio of Si/Zr was 8.
1.2 Characterization of Zr-MCM-41
X-ray diffraction (XRD) patterns were obtained using a
Siefert 3003 PTS diffractometer with Cu KĮ radiation (Ȝ =
0.15406 nm). Fourier transform infrared (FT-IR) spectra were
recorded using a Bruker Tensor 27 IR spectrometer and KBr
pellets in a range of 400–4000 cm–1 under atmospheric condi-
tions. Scanning electron micrographs (SEM) were obtained on
a Holand Philips XL-30 microscope with an accelerating
voltage of 25 kV. The sample was deposited on a sample holder
with an adhesive carbon foil and sputtered with gold. Nitrogen
adsorption studies were performed at liquid nitrogen tem-
perature using a BELSORP-miniII.
Compound 3: 2-(2-(1H-imidazol-4-yl)ethylamino)-2-(4-
chlorophenyl)acetonitrile. 1H NMR (300 MHz, CDCl3): į (2H,
t, J = 6, CH2), 2.96–3.09 (2H, m, CH2), 4.81 (1H, s, CH), 6.84
(1H, s, CHAr), 7.35–7.46 (4H, m, 4CHAr), 7.56 (1H, s, CHAr).
Mass (m/z): 260, 254, 234. Anal. Calcd (%): C, 59.89; H, 5.03;
Cl, 13.60; N, 21.19; Found: C, 59.95; H, 5.13; N, 21.19.
1.3 Synthesis of Į-aminonitrile derivatives
1.4 Recycling the catalyst
All solvents and reagents were purchased from Aldrich and
Merck and were of high-grade quality, and used without any
purification.
The catalyst is not soluble in boiling acetonitrile and it was
removed by hot filtration after reaction completion. In the
synthesis of 2-(4-chlorophenyl)-2-(4-methylbenzylamino)
acetonitrile the catalyst was recovered three times, washed
with diethyl ether, and reused in a similar reaction.
In a general procedure, a solution of an aromatic aldehyde (1
mmol), a primary amine (1.2 mmol), TMSCN (1 mmol), and
Zr-MCM-41 (0.03 g) in CH3CN (5 ml) was stirred under reflux
conditions for an appropriate time. After reaction completion
(monitored by TLC) the catalyst, which is not soluble in boil-
ing acetonitrile, was easily filtered off and the mixture was
cooled to room temperature. The solid products were collected
by filtration, washing with water and aqueous ethanol, and
purified by recrystallization from ethanol. For the oily products
the reaction mixture was poured into distilled water (15 ml) and
the product was extracted with chloroform (20 ml × 2) and
dried over MgSO4. The solvent was removed under reduced
pressure and crude product was purified by column chroma-
tography over silica gel (hexane–Et2O). Compounds 1, 2, and 3
are new products (Scheme 1) and the other products are known
compounds, and their physical and spectroscopic data have
been reported in the literature. Melting points were measured
using the capillary tube method with an electrothermal 9200
2 Results and discussion
Mesoporous silicate materials contain a chemically inert
silicate framework. To induce specific catalytic activity re-
searchers have tried to incorporate a variety of metals into the
mesostructure by either direct synthesis/ion-exchange or im-
pregnation. Among the transition metals, zirconium is consid-
ered to be important because of the possible strong polarization
of the Si–O–į···Zr+į linkages [14].
The surface acidity of the mesoporous solids is significantly
influenced by the incorporation of zirconium ions into the
framework. The addition of zirconium creates Brönsted acid
sites and also enhances the acid strength of both the Lewis and
Brönsted acid sites. The diameter of Zr4+ is much larger than
that of Si4+ and when smaller Si4+ ions are replaced by larger
Zr4+ ions in the framework of the solid the bond length of
Zr–O–Si clearly differs from that of Si–O–Si. This must lead to
the deformation of some structures and the generation of mi-
1
apparatus. H NMR spectra were recorded on a Bruker AQS
AVANCE-300 MHz or a 500 MHz spectrometer using TMS as
an internal standard (CDCl3 or DMSO-d6 solution).
Compound 1: 2,2'-(1,4-phenylene)bis(2-(4-methylben-
Cl
NH
NC
N
O
N
HN
H
H
N
N
Cl
NH
CN
NC
CN
Compound 1
Compound 2
Scheme 1. Structure of compound 1, 2, and 3.
Compound 3

Zohreh DERIKVAND et al. / Chinese Journal of Catalysis, 2011, 32: 532–535
3900 3400 2900 2400 1900 1400 900
400
Wavenumber (cmꢀ1)
Fig. 3. SEM micrograph of the freshly activated Zr-MCM-41.
Fig. 1. FT-IR spectrum of the calcined Zr-MCM-41.
zylamino)acetonitrile by the condensation of 4-methylben-
zylamine, 4-chlorobenzaldehyde, and TMSCN in different
solvents under heating as a model reaction. As shown in Table
1 the best results were obtained in refluxing acetonitrile. We
also determined the most efficient amount of catalyst required
and the reaction temperature as well as the best results were
obtained when using 0.03 g per 1 mmol of starting material
(Table 1). As shown in Table 1 this reaction is slower without
the catalyst and after 20 min we obtained 45% of the product
but the yield in the presence of 0.03 g of catalyst using the same
time was 95%.
1
2
3
4
5
6
7
2T/(o )
Fig. 2. XRD pattern of Zr-MCM-41.
This method was further employed to synthesize a variety of
new or known amino nitrile derivatives. To show the general
applicability of the method terephthaldehyde and a variety of
crostrain in the lattice cell [15]. This feature can be useful for
reactions that require both types of acid sites.
benzaldehyde
derivatives
such
as
aldehydes,
4-morpholinoaniline, histamine, and benzylamine derivatives
as an amine source were used in this reaction. The obtained
results are summarized in Table 2. Separation and purification
was very simple in these reactions. Zr-MCM-41 is not soluble
in boiling acetonitrile but the products are soluble in boiling
acetonitrile and the catalyst was separated by simple filtration.
Most of the products are not soluble in the reaction media at
room temperature and they were separated by filtration. For the
oily products the reaction mixture was poured into distilled
water and the product was extracted using chloroform and then
the solvent was removed under reduce pressure. The crude
products were purified by recrystallization from absolute EtOH
or in some cases (oily products) by column chromatography
over silica gel (hexane-Et2O). For the new products, com-
2.1 Characterization of the catalyst
The FT-IR spectrum of the prepared Zr-MCM-41 is given in
Fig. 1. The observed bands between 809 and 468 cm–1 are
assigned to the symmetric stretching and bending vibrations of
the Si–O–Si groups, respectively [16]. The stretching and
bending vibration modes of O–H in the Si–OH groups are
present at 3431 and 1631 cm–1, respectively.
MCM-41 samples are typically characterized by an intense
X-ray diffraction in the vicinity of 2ș = 2° and several other
peaks in the 2ș range from 3° to 8° [17]. The XRD pattern of
Zr-MCM-41 (Fig. 2) has a high-intensity (100) and two
low-intensity reflections ((110) and (200)). These are charac-
teristics of a hexagonal structure [18]. They exhibit long-range
order and good textural uniformity of the mesoporous struc-
ture.
Table
1
Synthesis of 2-(4-chlorophenyl)-2-(4-methylbenzylamino)
acetonitrile in a 20 min reaction
The SEM image revealed that the synthesized Zr-MCM-41
particles are composed of irregular large particles (Fig. 3).
The specific surface area, pore volume, and average pore
diameter of the Zr-MCM-41 was 676.2 m2/g, 1.2854 cm3/g,
and 2.06 nm, respectively.
Solvent (temperature)
EtOH (reflux)
Catalyst loading (g)
Yielda (%)
0.03
0.03
0.03
0.03
0.05
0.01
0.00
0.03
68
70
40
95
95
75
45
78
H2O (reflux)
Solvent free (80 °C)
CH3CN (reflux)
CH3CN (reflux)
CH3CN (reflux)
CH3CN (reflux)
CH3CN (r.t)
2.2 Catalytic activity
To study the catalytic activity of Zr-MCM-41, we initially
studied the synthesis of 2-(4-chlorophenyl)-2-(4-methylben-
aYields are related to the isolated pure products.

Zohreh DERIKVAND et al. / Chinese Journal of Catalysis, 2011, 32: 532–535
proceeded efficiently in acetonitrile under heating. The mild
Table 2 Synthesis of Į-aminonitrile in the presence of a catalytic
conditions and the use of a green, non toxic, inexpensive, and
reusable catalyst in high yields and in relatively short reaction
times are some of the advantages of this reaction.
amount of Zr-MCM-41 under heating in acetonitrile
H
Zr-MCM-41
NC
N
RCHO + R'NH + TMSCN
2
R'
CH CN
3
R
Entry
1
2c
3d
4e
5
Aldehyde
Amine
4-CH3C6H4CH2NH2
CHOC6H4CHO 4-CH3C6H4CH2NH2
Time (min) Yielda (%)
References
4-ClC6H4CHO
20
20
45
45
15
20
20
25
30
25
95, 85, 78b
95
92
85
89
95
90
89
95
84
1
2
3
4
5
6
7
8
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2,3-Cl2C6H3CHO 4-CH3C6H4CH2NH2
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to be identical [19]. In most cases the products were obtained in
quantitative yield and we did not detect any cyanohydrin
trimethylsilyl ethers as byproducts in this reaction.
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3 Conclusions
In summary, we report a simple and convenient procedure
for the synthesis and characterization of Zr-MCM-41 nanore-
actors. We used the synthesized nanoreactors as a green solid
acid catalyst for the preparation of Į-amino nitriles, which
18 Behrens P, Stucky G D. Angew Chem, Int Ed, 1993, 32: 696
19 Oskooie H A, Heravi M M, Bakhtiari K, Zadsirjan V,
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