BiOCl/FeOCl/SiO2 nanocomposite as an efficient novel catalyst toward the synthesis of 2-aryl-1hbenzimidazoles in mild aerobic condition

Article abstract of DOI:10.1080/24701556.2017.1284105

BiOCl/FeOCl nanorods composited by SiO₂ spherical nanoparticles as a novel nanocatalyst and also it has been synthesized using a co-precipitation procedure. Additionally, its structural along with the catalyst activity have been determined by t

Full text of DOI:10.1080/24701556.2017.1284105

Inorganic and Nano-Metal Chemistry
ISSN: 2470-1556 (Print) 2470-1564 (Online) Journal homepage: http://www.tandfonline.com/loi/lsrt21
BiOCl/FeOCl/SiO nano composite as an efficacy
2
novel catalyst toward synthesis of 2-aryl-1H-
benzimidazoles in mild aerobic condition
Hadi Mohammadi, Changiz Karami, Mahboobeh Bahri, Marayam
Mahmoudian Gilany & Mohammad Ali Taher
To cite this article: Hadi Mohammadi, Changiz Karami, Mahboobeh Bahri, Marayam Mahmoudian
Gilany & Mohammad Ali Taher (2017): BiOCl/FeOCl/SiO nano composite as an efficacy novel
2
catalyst toward synthesis of 2-aryl-1H-benzimidazoles in mild aerobic condition, Inorganic and
Nano-Metal Chemistry, DOI: 10.1080/24701556.2017.1284105
To link to this article: http://dx.doi.org/10.1080/24701556.2017.1284105
View supplementary material
Accepted author version posted online: 13
Mar 2017.
Submit your article to this journal
View related articles
View Crossmark data
Full Terms & Conditions of access and use can be found at
http://www.tandfonline.com/action/journalInformation?journalCode=lsrt21
Download by: [The UC San Diego Library]
Date: 13 March 2017, At: 12:02

ACCEPTED MANUSCRIPT
BiOCl/FeOCl/SiO
2
nano composite as an efficacy novel catalyst toward synthesis of 2-aryl-
1
H-benzimidazoles in mild aerobic condition
a
b
e
c
Hadi Mohammadi *, Changiz Karami *, Mahboobeh Bahri , Marayam Mahmoudian Gilany ,
d
Mohammad Ali Taher
a
Young Researchers and Elite Club, Kermanshah Branch, Islamic Azad University,
Kermanshah,Iran.
b
Department of Chemistry, Kermanshah Branch, Islamic Azad University, Kermanshah,Iran.
c
Department of Chemistry, Razi University, Kermanshah, Iran
d
Department of Chemistry, Shahid Bahonar University of Kerman, Kerman, Iran
e
Department of Chemistry, Islamic Azad University, Tonekabon Branch, Mazandaran, Iran.
*
Corresponding authors. E-mails: Changiz.Karami@gmail.com;
Hadimohammadi13@gmail.com
Abstract
BiOCl/FeOCl nano rods composited with spheres nano particles of SiO
2
as a novel nano catalyst
has been synthesized by using a co-precipitation procedure and structural properties of this
catalyst have been characterized by TEM, SEM, XRD, EDS as well as FT-IR spectroscopy. In
addition, this nano composite was utilized to synthesis of 2-arylbenzimidazole derivatives
efficiently that is described by the condensation of some aldehydes and o-phenylenediamines in
present of BiOCl/FeOCl/SiO nano composite as a novel nano catalyst Besides the investigated
2
variables such as the amount of catalyst, reaction temperature, the synergistic effect of BiOCl
and FeOCl, effect of various solvents, considered reusability of the catalyst are studied also. In
1
ACCEPTED MANUSCRIPT

ACCEPTED MANUSCRIPT
conclusion, synthesized BiOCl/FeOCl/SiO nano composite with some several remarkable
2
advantages like non-toxic nano catalyst, recovering and recycling for three runs minimally
without significant loss of catalytic activity under aerobic mild condition, short reaction times
and solvent free.
Keyword: Nanocomposite, Inorganic catalysis, Nanostructure, Catalytic properties,
Benzimidazoles
2
ACCEPTED MANUSCRIPT

ACCEPTED MANUSCRIPT
1
. Introduction
Over the past decade, nanomaterials have been widely investigated in the fields of chemistry,
physics, electronics, biology, and medicine because of their unique chemical and physical
characteristics, which are different from those of bulk materials [1]. Nevertheless, the
preparation of an artificially designed structure of nanoparticles with new properties such as high
surface area-to-volume ratios and tunable nanoscale sizes has attracted the attention of many
researchers. [2, 3] Recently, for the synthesis of organic compounds, supported nanoparticle
catalysts have been extensively studied, because the particle size decreases, relative number of
surface atoms increases so that activity will increases [4]. Nanoparticle catalysts can also be
easily separated and recycled with more retention of catalytic activity compare with their bulk
counterparts [5].
Further, an important class of heterocyclic compounds in the pharmaceuticals as cardio tonic
agents is the synthesis of potential antitumor [6], poly (ADP-ribose) phosphorilase inhibitors [7],
Histamine H4 receptor binders [8], anti-parasitic [9], cardiovascular [10], anti-cancers [6],
antimicrobials [11] and anti-hypertensive [11]. Moreover, due to the high importance of 2-aryl-
1
H-benzimidazoles for the preparation of biologically active molecules, their synthesis has
received considerable attention so, many reports have been cited in the literature which describe
the formation of 2-arylbenzimidazoles[12-15].
3
ACCEPTED MANUSCRIPT

ACCEPTED MANUSCRIPT
Nowadays bimetallic nanoparticles have attracted enormous attention as they provide exciting
opportunities not only for developing novel catalysts with unique but also improved activities
[
16]. In addition, one of the bimetallic catalyst heavy post-transition elements like Bismuth,
Lead, or Thallium with metallic transition elements like Pd or Pt for the selective organic
reaction such as oxidation of alcohols into aldehydes and carboxylic acids and catalytic oxidation
of glucose [17]. Additionally the promoting role of other post-transition elements such as Te or
transition metals has also been investigated for some organic reactions [18]. Generally,
bimetallic Co and Mn have been used as a catalyst for the synthesis of bis(indolyl)methanes in
the past [19].
As the purpose of the present work, the innovative BiOCl/FeOCl nano rods composited with
spheres nano particles of SiO
post-transition and transition elements (Bismuth and Iron) with different electronegativity to
investigation catalytic synergistic effect of BiOCl and FeOCl. Additionally, SiO nano particles
2
as a novel nano catalyst. Moreover, this study was designed with
2
not only play role as mediator agent for starting interactions but also as the substrate causes to
increase the catalyst surface throughout the reaction. Furthermore morphology,particle size and
crystal structure of nanocatalyst were explored by TEM, SEM, XRD, EDS, mapping, and FT-IR
spectroscopy. In the application of this catalyst, the impressive synthesis of 2-aryl-1H-
benzimidazoles has been carried out by Bi/Fe/SiO
. Experimental
.1. Measurement
All reagents and solvents were commercially available and were used as such. Silicon Oxide
2
nano composite.
2
2
(
SiO
2
, 25 wt%, 20-30 nm) was purchased from Nanostructured & Amorphous Materials, Inc.
4
ACCEPTED MANUSCRIPT

ACCEPTED MANUSCRIPT
The sample powder was analyzed by X-ray diffraction (XRD). This instrument (Philips,
xpertpro, nitherland) works with voltage and current settings of 40 kV and 30 mA, respectively
and uses Cu–Kα radiation (1.540510 Å). For the qualitative analysis, XRD diagrams were
recorded in the interval of 0°≤2θ≤80° at scan speed of 2°/min. The crystalline size of the
synthesized particle was calculated following Scherrer's equation. The morphology of catalysts
and their precursors were observed by means of a Philips XL30 scanning electron microscopy
(
SEM).
The morphology of the nano catalysts was studied by transmission electron microscopy
TEM). In addition some specimens of synthesized nano catalyst for TEM studies were prepared
(
by ultrasonic dispersion of the catalysts in ethanol, and the suspensions were dropped onto a
carbon-coated copper grid. TEM investigations were carried out using a (LEO 912 AB, 120 kV).
The FT-IR spectra of the samples (as KBr pellets) were recorded using a Rayleigh WQF-510
-
1
spectrophotometer in the range of 400–4000 cm . Melting points were determined using
1
Electrothermal 9300 Melting Point. HNMR spectra were recorded on Bruker 200 MHz NMR
spectrometer.
2
.2. Preparation of nano catalyst
First step was referred to BiCl
Bi/Fe] in ethanol and for different ratio of [Bi/Fe] the molars of BiCl
changed, and amount (15 wt %) of nano SiO were pre-mixed in a round-bottomed flask fitted
with a condenser and the resulting solution heated. Then Aqueous Na CO (0.5 mol/L) was
3
(0.5mol/l), FeCl
3
.6H
2
O (0.5 mol/l) with 1/1 molar ratios
, FeCl .6H O must been
[
3
3
2
2
2
3
added slowly to the mixed chloride solution, which was continuously stirred whilst the
temperature was maintained isothermally in the range of 70–85 °C. The final pH achieved was
5
ACCEPTED MANUSCRIPT

ACCEPTED MANUSCRIPT
1
0; this procedure took approximately 15 min to complete and reflux for 5–6 h. The precipitate
+
was first filtered and then washed several times with warm distilled water until no further Na
was observed in the washings tested by flame atomic absorption. Finally, the precipitate has been
dried at 150 °C for 16 h.
2
.3. Catalytic reaction procedures
A mixture of 1, 2-phenylenediamine (1mmol), aldehyde (1.1 mmol), and BiOCl/FeOCl/SiO
2
nano composite (0.015 g) as catalyst was heated at 70 °C for the appropriate time as mentioned
in. After the progress of reaction was completed that monitored by TLC, then the reaction was
dissolved in 10.0 mL of ethanol and transferred to a centrifuge tube and centrifuged at 4000 rpm
for 10 min to precipitate and recover the BiOCl/FeOCl/SiO
2
nano composite catalyst. The clear
supernatant was collected and the BiOCl/FeOCl/SiO nano composite catalyst was repeatedly
2
washed (dispersion in 3 mL of ethanol followed by centrifugation, three cycles) for recycling
experiments. The reaction mixture that was dissolved in ethanol poured into ice water (30 mL).
As a final point, the pure solid product was filtered, washed with ice water and subsequently
dried completely.
3
. Results and discussion
.1. Characterization of nano catalyst
In this study, BiOCl/FeOCl /SiO nano composite was synthesized by a mixing method
through BiCl (0.5mol/L) and FeCl .6H O (0.5 mol/L) with 1/1 molar ratio [Bi/Fe] in ethanol,
and 15 wt % nano SiO . Furthermore, the nano composite was characterized using X- XRD,
3
2
3
3
2
2
TEM, SEM, EDX, mapping, and FT-IR spectra. According to the XRD patterns of Bi/Fe Nano
6
ACCEPTED MANUSCRIPT

ACCEPTED MANUSCRIPT
particles that shown in Figure1 which demonstrates the reflections characteristic of BiOCl crystal
with the tetragonal structure (JCPDS Card 82 0485: a 3.888 Å and c 7.357 Å) and FeOCl crystal
with the tetragonal structure (JCPDS Card 24-1005: a 3.7715 Å and c 3.3026 Å).As can be seen
from XRD patterns the formation of BiOCl and FeOCl crystals have been supported on SiO
2
obviously [20, 21]. Additionally the crystal system of them were Tetragonal and Orthorhombic
along with space group of P4/nmm as well as Pmnm respectively.
According to the half-height of peck list of BiOCl/FeOCl nano rods, the crystallite diameters
of them were calculated using the Scherrer equation (Eq1).Therefore the estimated crystallite
diameters of BiOCl/FeOCl nano rods were around 21.35 nm. In addition, Figure 1 shows X-ray
pattern of BiOCl/FeOCl.
Figure 1
The TEM image in Figure 2 reveals that the product consisted of nanorod structure with the
average size of 10–15 nm. The characterization of new catalyst synthesized from the 1/1 sample
of BiOCl/FeOCl /SiO nano composite was carried out using SEM also. An additional all the
2
electronic micrographs of SEM-EDX were obtained from the powder specimens of these
materials, in addition SEM was used to obtain information on morphology and structure of
products, which was shown in rod-like nanostructures (Figure 3a). In general, the SEM
micrographs were in good agreement with the TEM observations. SEM-EDX aimed to obtain
information on their microstructural and metal dispersion properties (Figure 3 b). Since metal
7
ACCEPTED MANUSCRIPT

ACCEPTED MANUSCRIPT
mapping studies were used to understand the dispersion of metals and their agglomeration
behaviors on the support surface of nano catalyst including the Bi and Fe species over the
composition process were determined by EDX so that metal mappings analysis obtained from
different samples are given in Figure 3c. Overall, the EDX spectra of the nano composite has
been collected to evaluate their elemental composition along with percentage distribution , to
sum up Figure 3b presents a representative spectrum showing well-resolved peaks for both Bi
and Fe along with Si in synthesized nano catalyst.
Figure 2
Figure 3
In particular, BiOCl and FeOCl were observed that dispersed homogeneously amongst the
SiO
2
nano particles during the catalyst prepared by co-precipitations properly. As Figure 4 shows
nano particles, where the peaks of around
60 cm and 1400 cm were assigned to Bi-O of BiOCl and Fe-Cl respectively. Subsequently a
the FT-IR spectrum of the BiOCl /FeOCl among SiO
2
-1
-1
6
-1
-1
peak observed at 1100 cm indicated the Si-O and the one at 3600 cm could be attributed to the
O-H bond in the nano SiO surface.
2
Figure 4
.2. The catalytic synergistic effect of BiOCl /FeOCl/SiO nano composite
3
2
8
ACCEPTED MANUSCRIPT

ACCEPTED MANUSCRIPT
Thereafter catalytic synergistic effect of BiOCl and FeOCl in the range of 100% Bi to 100%
Fe for the synthesis of 2-(4-chlorophenyl)-1H-benzo[d]imidazole was studied (Figure 5a). The
result was shown that the yield of reaction for the synthesis of 2-(4-chlorophenyl)-1H-
benzo[d]imidazole increased with increasing the concentration of Bi so that the maximum yield
(
[
95%) of 2- (4-chlorophenyl)-1H-benzo[d]imidazole was achieved with the ratio of
Bi]/[Fe]=3/1. Since not Bi nor Fe nanoparticles are very active for the synthesis of 2-(4-
chlorophenyl)-1H-benzo[d]imidazole, it is difficult to attribute this enhancement to anything
other than a synergistic modification of BiOCl by FeOCl nanoparticles through the SiO nano
2
spheres as mediator agent.
3
.3. The investigated catalytic activity effect
The benzimidazole derivatives have been synthesized from the reaction of o-
phenylenediamine (1 mmol) and 4-chlorobenzaldehyde (1.1 mmol) as a model in the both
absence and presence of BiOCl /FeOCl nano rods, besides other catalyst such as nano-SiO
2
and
SiO under thermal solvent-free conditions for investigating optimum situations. As shown in
2
table1, this transformation required amount 0.015 g of a BiOCl /FeOCl nano rods as a nano
catalyst at 70°C for 17 min it has been chosen for the preparation of benzimidazole derivatives.
To summarize the optimized conditions were further extended for the synthesis of benzimidazole
derivatives.
3
.4. The efficacy of temperature on the rate of reaction
Dependency the rate of reaction with effect of temperature were carried out at different range
temperatures for the preparation of 2-(4-chlorophenyl)-1H-benzo[d]imidazole. According to the
result can observe that the reaction was not completed at room temperature, yet the reaction has
9
ACCEPTED MANUSCRIPT

ACCEPTED MANUSCRIPT
°
been continued smoothly and almost complete conversion of the product was observed at 50 C.
Further, increasing in temperature to 70, 100, and 110°C enhancement the rate of reaction (Table
1
). Therefore, the reaction temperature is kept at 70°C (providing short reaction time and high
yield).
3
.4. The effect of solvent
Certainly, solvent plays a critical role in chemical reactions therefore, we decided to
investigate the efficacy of various solvents and select an appropriate condition for the
preparation of benzimidazole. Moreover, we screened different solvents such as acetonitrile,
ethyl acetate, ethanol, methanol, dichloromethane, water, and solvent-free for the preparation of
benzimidazole as a typical example and the 4-chlorobenzaldehyde as well as 1,2-
phenylendiamine as the substrates in the presence of 0.015 g catalyst in different solvents
(
Table1). As a final point solvent-free was found to be the most efficient one for this conversion
in which the reactions in other solvents required longer reaction time and low yield. In addition,
the optimized conditions were further extended for the synthesis of substituted benzimidazole
1
13
(
Table 2), HNMR and CNMR spectra of compound was reported in supplementary
information (SI).
.5. The investigate of weight catalyst
3
In the next step, the effect of catalyst weight was studied to find the optimized amount of
nanocomposite catalyst as shown in Table 1, which the reaction was carried out by varying the
amount of the catalyst on the conversion of 2-(4-chlorophenyl)-1H-benzo[d]imidazole. As result
shows, it increased linearly with the catalyst weight up to 0.015g and then became constant so
that these results indicated the amount of nanocatalyst required for the conversions.
10
ACCEPTED MANUSCRIPT

ACCEPTED MANUSCRIPT
Table 1
3
.6. Plausible mechanism of the reaction
The Scheme 1 has been illustrated of proposed mechanism for the synthesis of the
benzimidazoles. As the best of our knowledge, firstly the BiOCl/FeOCl /SiO nano composite
activated the aldehyde group through forming a coordinate bond with the Lewis acid site of a
BiOCl/FeOCl over the surface of SiO as mediator agent. Next step involved of nucleophilic
2
2
addition by phenylene-1,2-diamine on the aldehyde produced intermediate (A). Since, ring
closure provided a five-member ring by catalyst (B). Then, the oxidation of the (B) might be
initiated by air as the oxidant agent for the preparation of (C) compound [20].
Scheme. 1
Table 2
3
.7. Reusability of the nano catalyst
For testing the reusability, the separated catalyst was reused in four consecutive reactions
between 4-chlorobenzaldehyde and o-phenylenediamine, by the way the conversion of the
reactant after four cycles was almost constant and catalytic activity was observed as compared
with the fresh catalyst (Figure 5b)
Figure 5
4
. Conclusions
11
ACCEPTED MANUSCRIPT

ACCEPTED MANUSCRIPT
Spheres nano particles of SiO composited with BiOCl/FeOCl nano rods was prepared by
2
using a co-precipitation procedure and investigated for affecting synthesis of benzimidazole
derivatives. Particularly, the optimum preparation conditions were identified with respect to
catalytic performance for the conversion of synthesis benzimidazole derivatives. Furthermore,
this catalyst have several advantages including short reaction times, excellent yields,
inexpensiveness, mild conditions, non-toxic catalyst, as well as simple operation and work-up.
Additionally, the nanocatalyst did not require volatile and hazardous organic solvents and an
additional ultrasound or microwave oven. Above all elimination of the solvent has obvious
environmental benefits in terms of the depletion of solvent waste. Overall, the nano catalyst
could recover and recycle for three times at least without any significant loss in catalytic activity
successfully.
Supporting Information
1
13
H NMR, and C NMR of material are provided in supporting information.
Acknowledgments
The authors are grateful to the Department of Chemistry, Kermanshah Branch, Islamic Azad
University of Kermanshah, Iran for the financial support for this research.
12
ACCEPTED MANUSCRIPT

ACCEPTED MANUSCRIPT
References
1
2
.
.
Rengaraj, S. and S.-H. Moon, Kinetics of adsorption of Co (II) removal from water and
wastewater by ion exchange resins. Water research, 2002. 36(7): p. 1783-1793.
Guo, Y., et al., Colorimetric detection of mercury, lead and copper ions simultaneously
using protein-functionalized gold nanoparticles. Biosensors and Bioelectronics, 2011.
2
6(10): p. 4064-4069.
3
.
Ghodrati, K., et al., Nano Silica Sulfuric Acid an Efficient and Recoverable
Heterogeneous Catalyst for the Preparation of Amidoalkyl Naphthols Under Solvent-
Free Conditions. Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal
Chemistry, 2015. 45(1): p. 15-20.
4
5
6
.
.
.
Mohanpuria, P., N.K. Rana, and S.K. Yadav, Biosynthesis of nanoparticles:
technological concepts and future applications. Journal of Nanoparticle Research, 2008.
1
0(3): p. 507-517.
Veisi, H., et al., Magnetically palladium catalyst stabilized by diaminoglyoxime-
functionalized magnetic Fe 3 O 4 nanoparticles as active and reusable catalyst for Suzuki
coupling reactions. Journal of Molecular Catalysis A: Chemical, 2015. 396: p. 216-223.
Denny, W.A., G.W. Rewcastle, and B.C. Baguley, Potential antitumor agents. 59.
Structure-activity relationships for 2-phenylbenzimidazole-4-carboxamides, a new class
of minimal DNA-intercalating agents which may not act via topoisomerase II. Journal of
Medicinal Chemistry, 1990. 33(2): p. 814-819.
13
ACCEPTED MANUSCRIPT

ACCEPTED MANUSCRIPT
7
.
White, A.W., et al., Potentiation of cytotoxic drug activity in human tumour cell lines, by
amine-substituted 2-arylbenzimidazole-4-carboxamide PARP-1 inhibitors. Bioorganic
& Medicinal Chemistry Letters, 2004. 14(10): p. 2433-2437.
8
.
Lee-Dutra, A., et al., Identification of 2-arylbenzimidazoles as potent human histamine
H4 receptor ligands. Bioorganic & Medicinal Chemistry Letters, 2006. 16(23): p.
6
043-6048.
9
1
.
Cedillo-Rivera, R.M., O, J. Med. Microbiol, 1992. 37: p. 221.
0.
Gungor, T., et al., Cardiotonic agents. Synthesis and cardiovascular properties of novel
2
-arylbenzimidazoles and azabenzimidazoles. Journal of Medicinal Chemistry, 1992.
5(23): p. 4455-4463.
3
1
1
1.
2.
Seyhan, E.S., N.; Nilgun, A.; Noyanalpan, N. Arzneimittel-Forschung, 1997. 47: p. 410-
12.
4
Heravi, M.M., et al., Synthesis of 2, 4, 5-triaryl-imidazoles catalyzed by NiCl 2· 6H 2 O
under heterogeneous system. Journal of Molecular Catalysis A: Chemical, 2007. 263(1):
p. 279-281.
1
1
3.
4.
Shaabani, A. and A. Rahmati, Silica sulfuric acid as an efficient and recoverable catalyst
for the synthesis of trisubstituted imidazoles. Journal of Molecular Catalysis A: Chemical,
2
006. 249(1): p. 246-248.
Trivedi, R., S.K. De, and R.A. Gibbs, A convenient one-pot synthesis of 2-substituted
benzimidazoles. Journal of Molecular Catalysis A: Chemical, 2006. 245(1): p. 8-11.
14
ACCEPTED MANUSCRIPT

ACCEPTED MANUSCRIPT
1
5.
Kidwai, M., et al., One-pot synthesis of highly substituted imidazoles using molecular
iodine: a versatile catalyst. Journal of Molecular Catalysis A: Chemical, 2007. 265(1): p.
1
77-182.
1
1
1
6.
7.
8.
Toshima, N. and T. Yonezawa, Bimetallic nanoparticles—novel materials for chemical
and physical applications. New Journal of Chemistry, 1998. 22(11): p. 1179-1201.
Kowshik, M., et al., Extracellular synthesis of silver nanoparticles by a silver-tolerant
yeast strain MKY3. Nanotechnology, 2003. 14(1): p. 95.
Hayashi, H., et al., Formation of an intermetallic compound Pd3Te with deactivation of
Te/Pd/C catalysts for selective oxidation of sodium lactate to pyruvate in aqueous phase.
Catalysis letters, 1993. 19(4): p. 369-373.
1
9.
Karami, C., et al., A novel method for synthesis of cobalt manganese oxide nano catalysts
as a recyclable catalyst for the synthesis of some bis (indolyl) methane derivatives.
Catalysis Communications, 2012. 27: p. 92-96.
2
2
0.
1.
Lin, S. and L. Yang, A simple and efficient procedure for the synthesis of benzimidazoles
using air as the oxidant. Tetrahedron Letters, 2005. 46(25): p. 4315-4319.
Li, L., et al., Template synthesis of hierarchical Bi2E3 (E= S, Se, Te) core− shell
microspheres and their electrochemical and photoresponsive properties. The Journal of
Physical Chemistry C, 2009. 113(42): p. 18075-18081.
15
ACCEPTED MANUSCRIPT

ACCEPTED MANUSCRIPT
Table 1. Optimum conditions for the preparation of 2-(4-chlorophenyl)-1H-benzo[d]imidazol
a
Entry
Solvent
Catalyst
Weight (g)
Catalyst
Temp.
(°C)
Time (h) Yield (%)
Effect of catalyst
No
1
2
3
4
Solvent-free
Solvent-free
Solvent-free
Solvent-free
70
70
70
70
24
24
24
0.015
0.015
0.015
SiO
nano particles
2
SiO
2
BiOCl/FeOCl/SiO
nano composite
2
17
95
Effect of temperature
5
6
7
8
9
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
0.015
0.015
0.015
0.015
0.015
BiOCl/FeOCl/SiO
nano composite
BiOCl/FeOCl/SiO
nano composite
BiOCl/FeOCl/SiO
nano composite
BiOCl/FeOCl/SiO
nano composite
BiOCl/FeOCl/SiO
nano composite
2
2
2
2
2
25
50
24
45
17
10
9
90
95
95
95
95
70
100
110
Effect of solvent
1
1
1
1
1
1
1
0
1
2
3
4
5
6
CH
AcOEt
CH Cl
3
CN
0.015
0.015
0.015
0.015
0.015
0.015
0.015
BiOCl/FeOCl/SiO
nano composite
BiOCl/FeOCl/SiO
nano composite
BiOCl/FeOCl/SiO
nano composite
BiOCl/FeOCl/SiO
nano composite
BiOCl/FeOCl/SiO
nano composite
BiOCl/FeOCl/SiO
nano composite
BiOCl/FeOCl/SiO
nano composite
2
Refluxed
Refluxed
Refluxed
Refluxed
Refluxed
70
25
20
25
28
25
17
25
90
95
90
90
90
95
95
2
2
2
2
2
2
2
2
MeOH
EtOH
Solvent-free
H
2
O
Refluxed
Effect of catalyst weight
1
1
1
7
8
9
Solvent-free
Solvent-free
Solvent-free
0.005
0.01
BiOCl/FeOCl/SiO
nano composite
BiOCl/FeOCl/SiO
nano composite
BiOCl/FeOCl/SiO
nano composite
2
2
2
70
70
70
17
17
17
40
80
95
0.015
16
ACCEPTED MANUSCRIPT

ACCEPTED MANUSCRIPT
1
9
Solvent-free
0.025
BiOCl/FeOCl/SiO
nano composite
2
70
17
95
a
Isolated yield.
17
ACCEPTED MANUSCRIPT

ACCEPTED MANUSCRIPT
Table 2. Synthesis of benzimidazole derivatives
H
N
O
BiOCl/FeOCl/SiO2 nano composite
NH2
NH2
+
C H
Solvent- Free,70 °C
N
R
R
1
2
3
a,
ENTRY
R
Time (min)
Yield(% (
b
1
2
3
4
5
6
7
8
9
4- OH
4-Me
4- Cl
25
18
17
96
95
95
80
95
93
90
95
95
95
95
94
96
3a
3b
3c
3d
3e
3f
3g
3h
3i
4- (CH
3
)
2
N
20
20
25
23
20
50
50
50
17
20
H
2-OH
4- MeO
4-Ph
4-CHO
3-NO2
1
1
1
1
0
1
2
3
3j
3k
3l
4-NO
2-Cl
4-F
2
3m
A
THE PRODUCTS WERE CHARACTERIZED BY
COMPARISON OF THEIR SPECTROSCOPIC AND
PHYSICAL DATA WITH AUTHENTIC SAMPLES
SYNTHESIZED BY REPORTED PROCEDURES.
B
YIELDS REFER TO PURE ISOLATED PRODUCTS.
18
ACCEPTED MANUSCRIPT

ACCEPTED MANUSCRIPT
Figure 1. XRD pattern of BiOCl/FeOCl nano rods.
19
ACCEPTED MANUSCRIPT

ACCEPTED MANUSCRIPT
Figure 2. TEM images of the catalyst BiOCl/FeOCl/SiO nano composite.
2
20
ACCEPTED MANUSCRIPT

ACCEPTED MANUSCRIPT
21
ACCEPTED MANUSCRIPT

ACCEPTED MANUSCRIPT
Figure 3. a) SEM images of the catalyst, b) EDX spectrum, c) mapping graph of BiOCl/FeOCl /
SiO nano composite.
2
22
ACCEPTED MANUSCRIPT

ACCEPTED MANUSCRIPT
a)
1
50
00
1
50
b)
3450 cm-1
1400 cm-1
600 cm-1
1100 cm-1
0
3900
3400
2900
2400
Wavenumber (cm )
1900
1400
900
400
-1
Figure 4. a) FT-IR spectrum of SiO
2
nano particles, b) BiOCl/FeOCl/SiO
2
nano composite.
23
ACCEPTED MANUSCRIPT

ACCEPTED MANUSCRIPT
24
ACCEPTED MANUSCRIPT

ACCEPTED MANUSCRIPT
Figure 5. a) Effect of Bi/Fe molar ratio on the catalytic performance 1=0/100%, 2=50/50%,
3
=75/25%, 4=25/75%, 5=100/0% of Bi/Fe, b) Reusability of the BiOCl/FeOCl nano rods.
25
ACCEPTED MANUSCRIPT

ACCEPTED MANUSCRIPT
NH2
NH2
NH2
N
H
H
R
O
+
A
R
H
H
N
O Air
H
NH2
N
H
R
N
R
N
N
C
B
R
BiOCl/FeOCl/SiO2 nano composite
Scheme. 1. The proposed mechanism for the synthesis of the benzimidazoles by BiOCl/FeOCl
SiO nano composite.
/
2
26
ACCEPTED MANUSCRIPT