Application of magnetic dicationic ionic liquid phase transfer catalyst in nuclophilic substitution ractions of benzyl halides in water

Article abstract of DOI:10.13005/ojc/320348

Magnetic dicationic ionic liquid (MDIL) was successfully prepared and evaluated as phase-transfer catalyst for nucleophilic substitution reactions. The reactions was occurred in water and furnished the corresponding benzyl derivatives in high yields. No evidence for the formation of by-product for example benzyl alcohol of the reaction was observed and the products were obtained in pure form without further purification.

Full text of DOI:10.13005/ojc/320348

ISSN: 0970-020 X
CODEN: OJCHEG
2016, Vol. 32, No. (3):
Pg. 1691-1695
ORIENTAL JOURNAL OF CHEMISTRY
An International Open Free Access, Peer Reviewed Research Journal
www.orientjchem.org
Application of Magnetic Dicationic Ionic Liquid Phase Transfer
Catalyst in Nuclophilic Substitution Ractions of Benzyl Halides
in Water
MANOUCHEHR AGHAJERI1, ALI REZA KIASAT2 and BIJAN MOMBENI GOODAJDAR1*
1Department of Chemistry, Islamic Azad University Omidiyeh Branch, Omidiyeh, Iran
2Department of Chemistry, College of Science, Shahid Chamran University, Ahwaz,
*Corresponding author E-mail: bmombini@gmail.com
http://dx.doi.org/10.13005/ojc/320348
(Received: February 24, 2016; Accepted: April 02, 2016)
ABSTRACT
Magnetic dicationic ionic liquid (MDIL) was successfully prepared and evaluated as phase-
transfer catalyst for nucleophilic substitution reactions. The reactions was occurred in water and
furnished the corresponding benzyl derivatives in high yields. No evidence for the formation of by-
product for example benzyl alcohol of the reaction was observed and the products were obtained
in pure form without further purification.
Keywords: Green chemistry, Substituted reaction, Phase transfer catalyst.
INTRODUCTION
One of the most important strategies to
overcome this limitation is the utilization of phase
transfer catalyst such as ionic liquid (IL).
Green chemistry is a major issue of modern
chemistry currently. The use of environmentally
benign solvent instead of traditional organic solvents
is the important and efficient strategy in green
chemistry.Water is a promising green solvent for use
in chemistry because it is cheap, readily available,
and nontoxic. There is increasing recognition that
organic reactions carried out in water may offer
advantages over those in organic solvents
However, the poor solubility of reactants in water
is the main obstacle to the use of water as reaction
solvent.3
Phase-Transfer Catalysis (PTC) is a well-
known method of promoting reactions between
reagents with opposite solubility preferences.In such
systems each reactant is dissolved in the appropriate
solvent. Commonly, the two solvents are immiscible
to one another, and then a phase-transfer catalyst
is added to facilitate the transport of one reactant
into the other phase. By means of the catalytic
step, the enhanced reactivity between the ionic
species leads to increase of the rate of the desired
1-2
.
reaction 3-6
.

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As a part of our program aiming at with NaN3 in water at room temperature and under
developing selective and environmental friendly reflux conditions.Circumscribe in reflux condition that
methodologies for the preparation of fine chemicals results is better. This catalyst acted very efficiently
and in continuation of our interest in magnetic ionic and it converts different benzyl halides to their
liquid promoted organic reactions 7, in this paper, we corresponding benzyl azide in high isolated yields.
report on the evaluation of nucleophilic substitution The obtained results of the reaction are given in
reactions of benzyl halides in the H2O-MDIL system. Table 1.
The method is straightforward and furnish the
corresponding benzyl derivatives in high yields.
1HNMR spectra of the crude products
clearly showed the formation of benzyl azide and
no evidence for the hydrolysis of benzyl halides to
the alcohols was observed, which proved that the
RESULTS AND DISCUSSION
The magnetic dicationic ionic liquid as a reactions proceeded cleanly. On the other hand, in
catalyst was synthesized according to previously the absence MDIL, the reaction was sluggish and,
8
our reported . Scheme 1 illustrates the synthetic even after prolonged reaction time, a considerable
route for the preparation of MRTDIL synthesized and amount of starting material remained. Moreover,
characterized in this study.
the reaction mixture was contaminated with alcohol.
This observation was confirmed with the presence
To evaluate the catalytic activity of PEG- of alcohol on the TLC plate.
MDIL, the reaction of benzyl halides with NaN3
was examined as a model reaction. The results are
summarized in Table 1.
The effect of the reaction temperature on the
reaction time of benzyl bromide was investigated at
reaction temperatures ranging from 25 to 90°C.The
We first examined the catalytic ability of results show that the suitable reaction temperature
MDIL for conversion of benzyl halides to benzyl azide is 90°C.
Step 1
(CH2)3
Cl
Cl
(CH2)3
N
N
N
N
N
N
2
MeOH
reflux, 24h
Cl-
Cl-
[C4(mim)2]Cl2
RDIL (A)
FeCl3 neat condition
Stepe 2
(CH2)3
N
N
N
N
2-
2 FeCl4
2-
[C4(mim)2](FeCl4
)
2
(MRTDIL) (B)
Scheme 1: Synthesis of MDIL

AGHAJERI et al., Orient. J. Chem., Vol. 32(3), 1691-1695 (2016)
1693
The reaction was carried out in diethyl
ether, n-hexane, acetonitrile, dichloromethane, ethyl
acetate and water.From the results, it fallows that the
best solvent for this reaction is water.Thus, water is
an excellent solvent in terms of cost, availability, and
environmental impact and shorter reaction times.
Benzyl halide bearing activated and deactivated
groups were quickly and efficiently converted to the
virtually pure corresponding products in high isolated
yields. No evidence for the formation of alcohol by
products of the reactions was observed and the
products were obtained in pure form without further
purification.
MDIL(20 % mol)
5 ml H2O, ref lux
CH2X
+
NaN3
CH2N3
G
G
Scheme 2: Synthesis of Benzyl Azide from Benzyl halide in the presence of magnetic phase
transfer catalyst
Table 1: Reaction of various benzyl halids with sodium
azide in the presence of MDIL in water
Entry
Benzyl halide
product
Time (min) Yield (%)
Br
Cl
N3
1
2
60
55
82
84
N3
3
4
5
6
Br
N3
60
50
86
87
N3
Cl
H3CO
H3CO
Cl
60
50
82
80
Cl
N3
Cl
Cl
Br
N3

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H
-
H
FeCl4
C4mim
X
O
H
H
-
FeCl4
Na+
O
O
Y-
O
H
X
H
Y= N3 , CN-
-
H
H
Scheme 3: Postulated roles of H2O-MDIL in the nucleophilic substitution
MDIL showed remarkable reactivity as a
Typicalprocedureforthenucleophilicsubstitution
benzyl halides with sodium azide
Lewis acid reagent and considerably accelerated
the reactions. It seems that H2O units in H2O-MDIL
encapsulate alkali metal cations, much like crown
ethers, and these complexes cause the anion to
be activated. The 1-methylimidazol-3-ium units
introduced ionic liquid property to the catalyst. In
addition, FeCl4- groups at the IL, probably, facilitates
the substitution reaction (Scheme 3).
To a mixture of the benzyl halide (1.0 mmol)
and NaN3 (3 mmol) in water (5 ml), MDIL (20 % mol)
was added.The suspension was magnetically stirred
under reflux conditions for the time shown in Table
1. After complete consumption of starting material
as judged by TLC (using n-hexane–ethyl acetate
as eluent), the mixture was extracted with ether
(2 × 10 ml). The combined organic extracts (dried
over CaCl2) were evaporated under reduced
pressure.The desired benzyl azide was obtained in
good to excellent isolated yields
MATERIAL AND METHODS
Melting points were measured on an
Electro thermal 9100 apparatus and are uncorrected.
1H & 13CNMR spectra were recorded on a Bruker
Advanced DPX 400 MHz instrument spectrometer
using TMS as the internal standard in CDCl3. IR
spectra were recorded on a BOMEM MB-Series
1988 FT-IR spectrometer. Raman spectroscopy
were recorded on a Bruker RFS 100/s Raman
spectrometer. Benzyl halides were purchased
from Merck Company in high purity. Products were
characterized by comparison of their physical and
spectroscopic data with those of known samples.
The purity of products and reaction monitoring was
accomplished by TLC on silica gel Poly Gram SILG/
UV 254 plates.
CONCLUSION
In conclusion, we have successfully
developed a simple and green catalytic procedure for
the efficient synthesis of benzyl azides using MDIL
and under mild reaction conditions.MDIL can replace
the ILs and other homogeneous catalysts with
reasonable recovery and reusability and therefore
suitable for industrial applications.
ACKNOWLEDGMENTS
We gratefully thank Islamic Azad University,
Science and Research Branch Omidiyeh for financial
support.
REFERENCES
1.
2.
3.
Lindström, U.M.Chem.Rev. 2002, 102, 2751-
2771.
Siskin, M.; Katritzky, A. R. Chem. Rev. 2001,
101, 825-836.
2005, 64, 179-185.
4.
5.
Xue, S. J.; Ke, S.-Y.; Wei, T.-B.; Duan, L.-P.;
and Guo, Y.-L. J. Chin. Chem. Soc. 2004, 51,
1013-1018.
Mahdavi, H.;Tamami, B.React.Funct.Polym.
El-Saied, A. A.; Mohamed, A. A.; and El-

1695
AGHAJERI et al., Orient. J. Chem., Vol. 32(3), 1691-1695 (2016)
Gharably, A. A. J. Chin. Chem. Soc. 2004, 51,
983-990.
Kiasat, A. R.; Fallah Mehrjardi, M. J. Chin.
Chem. Soc. 2008, 55, 639-642.
559-570. (c) Godajdar, B. M.; Kiasat, A. R. J.
Chil. Chem. Soc. 2013, 58, 1850-1852. (d)
Godajdar, B. M.; Soleimani, S. J. Chin. Chem.
Soc. 2014, 61, 447-452
6.
7.
(a) Godajdar, B. M.; Kiasat, A. R.; Hashemi, 8.
M. M. J. Mol. Liq. 2013, 183, 14-19. (b) B.
M. Godajdar, B. M.; A. R. Kiasat, A. R.; M.
M. Hashemi, M. M. Heterocycles, 2013, 87,
Mombaini Godajadar, B.; Kiasat, A. R.;
Ezabadi, A. Orient. J. Chem. 2015, 31, 483-
487.