Friedel-Crafts acylation of anisole with octanoic acid over acid modified zeolites

Article abstract of DOI:10.1039/c4ra02278e

Friedel-Crafts acylation of anisole using octanoic acid as a green acylating agent was studied over zeolites free of solvent. It was found that a mixed organic acid, composed of tartaric acid and oxalic acid, modified Hβ (Mix-Hβ) zeolite showed the best catalytic performance among the catalysts studied. The conversion of octanoic acid and the selectivity for p-octanoyl anisole were 72.7% and 82.5%, respectively. Inductively coupled plasma analysis (ICP) and ²⁷Al MAS NMR indicated dealumination of the parent Hβ zeolite due to the treatment of the mixed organic acid, leading to more accessible active sites and accounting for the better catalytic activity of the Mix-Hβ zeolite. Furthermore, lower strength of Lewis acid sites and Broensted acid sites of the Mix-Hβ zeolite, as demonstrated by Fourier Transform Infrared Spectrometry after adsorption of pyridine (Py-IR), are advantageous to suppress the demethylation of anisole and the subsequent esterification of thus formed phenol, accounting for its higher selectivity toward p-octanoyl anisole.

Full text of DOI:10.1039/c4ra02278e

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Friedel–Crafts acylation of anisole with octanoic
acid over acid modified zeolites
Cite this: RSC Adv., 2014, 4, 27116
Guoyi Bai,* Jie Han, Huanhuan Zhang, Chen Liu, Xingwang Lan, Fei Tian, Zhen Zhao
and Hui Jin
Friedel–Crafts acylation of anisole using octanoic acid as a green acylating agent was studied over zeolites
free of solvent. It was found that a mixed organic acid, composed of tartaric acid and oxalic acid, modified
Hb (Mix-Hb) zeolite showed the best catalytic performance among the catalysts studied. The conversion of
octanoic acid and the selectivity for p-octanoyl anisole were 72.7% and 82.5%, respectively. Inductively
27
coupled plasma analysis (ICP) and Al MAS NMR indicated dealumination of the parent Hb zeolite due to
the treatment of the mixed organic acid, leading to more accessible active sites and accounting for the
better catalytic activity of the Mix-Hb zeolite. Furthermore, lower strength of Lewis acid sites and
Br o¨ nsted acid sites of the Mix-Hb zeolite, as demonstrated by Fourier Transform Infrared Spectrometry
after adsorption of pyridine (Py-IR), are advantageous to suppress the demethylation of anisole and the
subsequent esterification of thus formed phenol, accounting for its higher selectivity toward p-octanoyl
anisole.
Received 15th March 2014
Accepted 12th June 2014
DOI: 10.1039/c4ra02278e
www.rsc.org/advances
the other hand, solid acid catalysts, such as heteropoly acids and
1
. Introduction
19–25
26–29
polyoxometalates
and zeolites,
are regarded as potential
Friedel–Cras acylation of aromatics is by far the most popular green catalysts. Thus, some researches have been carried out
1,2
method for the production of aromatic ketones, which are key using carboxylic acids as acylating agents catalyzed by solid acid
intermediates of ne chemicals, pharmaceuticals, insecticides, catalysts for the purpose of green synthesis. Particularly, zeolites
3–5
plasticizers, dyes, perfumes, and agrochemicals. Presently, have attracted special attention in this transformation due to
Friedel–Cras acylation is usually carried out using acid chlo- their pore structures and unique acid properties. For example,
6
7,8
16
rides or acid anhydrides as the acylating agents and catalyzed Ma et al. have investigated the Friedel–Cras acylation of ani-
9
–14
3 3
by Lewis acids, such as AlCl , BF
, or Br ¨o nsted acids, typically sole with substituted benzoic acids and alkanoic acids over Y
SO
or HF. However, the procedures using acid chlorides and zeolite and found Lewis acid sites were more effective and
H
2
4
18
acid anhydrides suffer from severe corrosion to reactors as well selective for the target reaction. Wagholikar et al. have studied
as waste problems, mainly due to the formed HCl or carboxylic the Friedel–Cras acylation of anisole with different long-chain
acids during the reaction. On the other hand, the above cata- carboxylic acids over three large pore zeolites, and found that
lysts have limitations such as environmental pollution hazards both the type of zeolites and the chain length of carboxylic acids
arising from the disposal of potential toxic wastes, reactor can inuence the reaction results. Although progresses have been
corrosion, and difficulties in their handling. Furthermore, the made by such catalysts, problems still can not be totally solved
catalyst amounts to be employed are sometimes much more because of the prolonged reaction time and/or high molar ratio of
than the stoichiometric quantity required, as the catalysts have aromatics to carboxylic acids, as well as low conversion of
a tendency for complex formation with either the reactants or carboxylic acids. Therefore, it is desirable to develop an efficient
the products. Thus, considering both the acylating agents and catalyst for the green Friedel–Cras acylation.
2,30
the catalysts are not eco-friendly for current methods, there has
been great demand to develop a green method due to the report our recent studies on the green Friedel–Cras acylation
environmental and economical concerns.
with the acylation of anisole with octanoic acid to p-octanoyl
In the continuation of our previous works,
we herein
Carboxylic acids are regarded as potential green acylating anisole (p-OA) being chosen as a model system. A series of
agents in the Friedel–Cras acylation because water is the only zeolites was tested and a mixed organic acid, composed of tar-
15–18
byproduct derived from carboxylic acid aer the acylation.
On taric acid and oxalic acid, modied Hb (Mix-Hb) zeolite showed
the best catalytic performance among the catalysts studied. The
activities of the zeolites were correlated with their structures
Key Laboratory of Chemical Biology of Hebei Province, College of Chemistry and using appropriate characterizations and a possible mechanism
Environmental Science, Hebei University, Baoding 071002, PR China. E-mail:
was also proposed.
baiguoyi@hotmail.com; Fax: +86-312-5937102; Tel: +86-312-5079359
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2. Experimental
2.1. Materials
Most reagents were purchased from Baoding Huaxin Reagent
and Apparatus Co., Ltd. and were used as received without
further purication. Particularly, the HZSM-5, HY, MCM-41 and Scheme 1 Friedel–Crafts acylation of anisole with octanoic acid.
Hb zeolites were commercial samples purchased from Tianjin
Chemist Catalyst Co., Ltd.
petroleum ether–dichloromethane ¼ 4 : 1 as eluent and further
1
identied by H-NMR (Bruker Avance III 600 MHz).
2
.2. Catalyst preparation
1
p-OA. Colorless crystals. H NMR (600 MHz, CDCl
J ¼ 8.4 Hz, 2H), 6.96 (d, J ¼ 9.0 Hz, 2H), 3.89 (s, 3H), 2.94 (t, J ¼
.2 Hz, 2H), 1.77–1.72 (m, 2H), 1.41–1.28 (m, 8H), 0.92 (t, J ¼ 6.6
Hz, 3H).
3
) d 7.98 (d,
Oxalic acid modied Hb zeolite was prepared by impregnating
1
solution of oxalic acid at 80 C for 1 h. Then, the sample was

.0 g of the parent Hb zeolite into 25 mL of an aqueous 1 M
7
ꢀ
ltered, washed with deionized water for 5 times, dried at
ꢀ
ꢀ
130 C and calcined at 500 C for 4 h. The prepared catalyst was
3
. Results and discussion
labeled as OA-Hb. Moreover, lactic acid, citric acid and tartaric
acid modied Hb zeolites were prepared by the same method 3.1. Catalyst selection
and labeled as LA-Hb, CA-Hb, TA-Hb, respectively. 2 M-OA-Hb, 2
It is well known that carboxylic acids are not active enough as
acylating agents in the Friedel–Cras acylations. Therefore,
M-TA-Hb and Mix-Hb zeolites were prepared by impregnating
.0 g of the parent Hb zeolite into 25 mL of an aqueous 2 M
solution of oxalic acid, tartaric acid, or mixed organic acid
16
1
selection of a suitable catalyst is crucial to the efficient acylation
of anisole with octanoic acid. Thus, some commercial zeolites,
such as HZSM-5, HY, and Hb zeolite, were rst examined and
the representative results are listed in Table 1. It is clear that the
Hb zeolite was the most effective one among them, which can
be ascribed to the special structure of Hb zeolite and the char-
acteristics of this reaction. The conversion of octanoic acid was
ꢀ
(
oxalic acid-to-tartaric acid molar ratio ¼ 1 : 1) at 80 C for 1 h.
Aer that, the samples were ltered, washed with deionized
ꢀ
ꢀ
water for 5 times, dried at 130 C and calcined at 500 C for 4 h.
2.3. Catalyst characterization
4
3.3% and the selectivity for p-OA was 73.4% over Hb zeolite,
X-ray diffraction (XRD) measurements were carried out on a
Bruker D8 advance diffractometer with Cu Ka radiation. Bulk
compositions were identied by inductively coupled plasma
analysis (ICP) on a Thermo VISTA-MPX spectrometer. BET
surface area and total pore volume were calculated using a
but still lower than our expectation. Considering the benet of
acid modication,
28–30
a series of organic acid modied Hb
zeolites was then investigated. As envisaged, these modied
zeolites showed better catalytic performance than the parent Hb
zeolite, especially in the cases of the OA-Hb and TA-Hb zeolites.
The conversion of octanoic acid was increased to 66.2% over the
TA-Hb zeolite and the selectivity for p-OA was increased to
2
7
Micromeritics Tristar II 3020 surface area and pore analyzer. Al
MAS NMR spectra were recorded on a Varian Innityplus 300M
Hz spectrometer. NH
3
temperature programmed desorption
8
3.7% over the OA-Hb zeolite, both being the best results
(
NH -TPD) experiments were performed on a TP-5000 instru-
3
among the modied zeolites. However, the high conversion and
ment equipped with a thermal conductivity detector. Fourier
Transform Infrared Spectrometer aer adsorption of pyridine
(
Py-IR) was measured on a Bruker EQUINOX55 spectrometer to
Table 1 Results of different zeolites for Friedel–Crafts acylation of
anisole with octanoic acid
determine the surface acidity of zeolites. Zeolite wafers were

a
rst mounted in a vacuum cell. The samples were then pre-
ꢀ
treated at 500 C under vacuum for 0.5 h, aer that pyridine
Selectivity (%)
vapor was adsorbed onto the sample, followed by infrared
ꢀ
ꢀ
Conversion of
octanoic acid (%)
Methyl
octanoate
Phenyl
octanoate
spectrometer characterization at 150
respectively.
C and 450 C,
Zeolite
p-OA
HZSM-5
HY
MCM-41
1.2
2.5
0.2
25.0
84.3
80.0
73.4
68.3
69.5
83.7
73.5
82.5
84.9
76.0
56.7
4.9
0
14.7
18.0
17.2
9.0
14.9
7.4
15.6
6.4
0
2
.4. Catalyst activity test
Friedel–Cras acylation of anisole with octanoic acid, as shown Hb
43.3
50.9
49.8
51.2
66.2
72.7
62.5
75.8
8.0
9.3
5.8
4.9
7.0
4.8
6.0
5.7
LA-Hb
in Scheme 1, was carried out in a 25 mL round-bottom ask. In a
typical run, anisole (2.70 g, 25.0 mmol), octanoic acid (1.80 g,
CA-Hb
OA-Hb
TA-Hb
Mix-Hb
12.5 mmol), and catalyst (0.5 g) were charged into the ask and
ꢀ
stirred at 155 C for 6 h under nitrogen atmosphere. The reac-
tion mixtures were analyzed by a gas chromatography (GC) 2 M-OA-Hb
7.1
12.6
2
M-TA-Hb
using a 30 m SE-30 capillary column and the products were
conrmed by GC-MS (Agilent 5975C). p-OA was also isolated by
a
Reaction conditions: octanoic acid-to-anisole molar ratio: 1 : 2,
ꢀ
column chromatography on 200–300 mesh silica gel using reaction time: 6 h, zeolite amount: 0.5 g, reaction temperature: 155 C.
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selectivity can not be achieved simultaneously over one catalyst. Table 2 Structural properties of the zeolites
Thus, to obtain a more efficient catalyst, we prepared a mixed
2
ꢁ1
3
ꢁ1
a
Zeolite
Surface area (m g
)
Pore volume (cm g
)
Si/Al
organic acid, composed of tartaric acid and oxalic acid, modi-
ed Hb zeolite and tested in this reaction. As expected, both
good conversion and selectivity are obtained over this novel Mix-Hb
catalyst. The conversion of octanoic acid and the selectivity for TA-Hb

Hb
432
543
508
498
0.28
0.34
0.32
0.33
12
44
28
46
OA-Hb
p-OA were 72.7% and 82.5%, respectively. The catalytic perfor-
a
mance of 2 M-OA-Hb and 2 M-TA-Hb zeolites were also tested
for comparison. As can be seen, the conversions of octanoic acid
were both improved at about 10.0% with the increase of the
concentration of organic acids used for modication. However,
the selectivities for p-OA were nearly unchanged, indicating that
the selectivity is not affected by the concentration of organic
acids used for modication. Thus, there should be certain
synergistic effect between tartaric acid and oxalic acid during
modication, accounting for the best catalytic performance of
Mix-Hb zeolite in this transformation. Therefore, Mix-Hb zeolite
was selected as the catalyst of choice for further investigation.
Calculated from the ICP results.
due to their strong coordination complexation with aluminum
cation of the Hb zeolite and in line with the previous reports.
In order to further investigate the dealumination effect of the
mixed organic acid, Al MAS NMR spectra of the parent Hb and
Mix-Hb zeolites were tested and presented in Fig. 2. Both
samples show two major peaks at about 0 and 53 ppm, corre-
sponding to octahedrally coordinated nonframework Al sites
3
0–32
2
7
33
and tetrahedrally coordinated framework Al sites, respectively.
It is obvious that the strength of both peaks markedly decreased
by roughly 70% aer the mixed organic acid treatment, ascribed
to the dealumination of the parent Hb zeolite and in accordance
with the ICP results. Consequently, combined with the experi-
mental data (Table 1), we suggested that dealumination of the
parent Hb zeolite resulted in the Mix-Hb zeolite having more
accessible active sites and then accounted for its higher activity.
NH -TPD analyses were carried out to determine the number
3
and types of acidic sites on the surfaces of the parent Hb, Mix-
Hb, TA-Hb and OA-Hb zeolites by the measurement of the
3
.2. Catalyst characterization
XRD patterns of the parent Hb, Mix-Hb, TA-Hb and OA-Hb
zeolites are shown in Fig. 1. As can be seen, the characteristic
diffraction peaks of the modied zeolites are at about 7.5 and
ꢀ
ꢀ
22.5 , just like those of the parent Hb zeolite, indicating that the
modied zeolites still kept the Hb type. However, the intensity
of the characteristic diffraction peaks of the modied zeolites
all decreased, especially for the Mix-Hb zeolite, indicating that
acid treatments led to small crystals of the modied zeolites.
BET surface areas and pore volumes of the parent Hb, Mix-
Hb, TA-Hb and OA-Hb zeolites are listed in Table 2. We found
that the BET surface areas and pore volumes of the three
modied Hb zeolites both increased aer the acid treatments
and Mix-Hb zeolite exhibited the largest surface area and pore
volume. Furthermore, the bulk Si/Al molar ratios of the parent
Hb, Mix-Hb, TA-Hb and OA-Hb zeolites were calculated from the
ICP results and are also listed in Table 2. The Si/Al molar ratios
markedly increased aer the organic acid treatments, especially
for the oxalic acid modied zeolite, and thus dealumination of
the zeolites should occur under the acid treatments, probably
amounts of NH desorbed at different temperatures, as shown
3
ꢀ
in Fig. 3. The strong peaks centered at about 250 C are assigned
to the weakly acidic sites and the peaks located approximately at
ꢀ
4
00 C to the moderately-strong acidic sites according to the
34,35
literatures.
It is obvious that the amounts of the weakly
acidic sites of the modied Hb zeolites markedly decreased
compared with the parent Hb zeolite. In contrast, the amounts
of the moderately-strong acidic sites kept relatively stable. Thus,
careful inspection of the reaction data (Table 1) together with
the NH -TPD results suggests that a catalyst having an
3
27
Fig. 1 XRD patterns of the parent Hb (a), Mix-Hb (b), TA-Hb (c) and Fig. 2
Al MAS NMR patterns of the parent Hb (a) and Mix-Hb (b)
OA-Hb (d) zeolites.
zeolites.
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3
Fig. 3 NH -TPD profiles of the parent Hb (a), Mix-Hb (b), TA-Hb (c)
and OA-Hb (d) zeolites.
Scheme 2 Possible mechanism for the acylation of anisole with
octanoic acid.
Br ¨o nsted acid sites decreased at about 68% (from 0.84 to 0.27),
more than that of Lewis acid sites (Table 3), indicating that the
acid modication causes different variation on different acid
sites. When the desorption temperature further increased to
ꢀ
4
50 C, the amounts of both Lewis acid sites and Br ¨o nsted acid
sites of the two catalysts decreased in different extent, indi-
cating the desorption of pyridine adsorbed on the weakly acid
sites of zeolites (Table 3). It is obvious that the Mix-Hb zeolite
possesses a little more weakly Br ¨o nsted acid sites and much less
both strongly Lewis acid sites and Br ¨o nsted acid sites,
compared with the parent Hb zeolite. Thus, we can conclude
that the treatment by a mixed organic acid mainly reduced the
amount of the strongly Lewis acid sites and Br ¨o nsted acid sites;
whereas, the weakly acid sites still kept in a high level in the
Fig. 4 Py-IR spectra of the parent Hb (a) and Mix-Hb (b) zeolites at Mix-Hb zeolite.
ꢀ
1
50 C.
3.3. Reaction mechanism
A possible mechanism is nally proposed based on the GC-MS
results (Scheme 2). The main reaction is the C-acylation of
anisole with octanoic acid over Mix-Hb zeolite to generate p-OA
appropriate amount of weakly acidic sites is in favor of the
desired transformation, in agreement with our previous
report.
30
38,39
1, the target product.
This transformation is ascribed to the
Py-IR was then carried out to study the effect of acid treat-
presence of Lewis acid sites on Hb zeolites, which could
chemisorb octanoic acid via coordination. Then, the octanoic
acid coordinated on Lewis acid sites would preferentially attack
at the aromatic ring in its para-position to generate product 1; in
contrast, the attack at its ortho-position is markedly inhibited
due to the steric effect of octyl group, making the ortho-position
substituted byproduct not detectable by GC-MS.
ment on the Lewis acid and Br ¨o nsted acid properties of the
zeolites. Py-IR spectra of the parent Hb and Mix-Hb zeolites at
ꢀ
1
50 C are shown in Fig. 4. It is clear that the amounts of both
ꢁ
1
Lewis acid sites (at about 1450 cm ) and Br ¨o nsted acid sites (at
about 1540 cm ) markedly decreased aer the mixed organic
acid treatment.
ꢁ
1
36,37
Furthermore, the relative amount of
a
Table 3 Br o¨ nsted acid sites and Lewis acid sites of the zeolites
ꢀ
ꢀ
Total acid sites 150 ( C)
Strongly acid sites 450 ( C)
Weakly acid sites
Zeolite
Br ¨o nsted acid sites
Lewis acid sites
Br ¨o nsted acid sites
Lewis acid sites
Br ¨o nsted acid sites
Lewis acid sites
Hb
Mix-Hb
0.84
0.27
3.54
1.71
0.77
0.16
2.11
0.31
0.07
0.11
1.43
1.40
a
Relative amounts calculated from the Py-IR results.
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In addition, octanoic acid will be protonated in the presence
of Br ¨o nsted acid sites on Hb zeolites. The protonated octanoic
acid will attack at the oxygen atom of anisole (O-acylation) to
produce phenyl octanoate 2, together with the formation of
6 C. Anand, B. Sathyaseelan, L. Samie, A. Beitollahi, R. Pradeep
Kumar, M. Palanichamy, V. Murugesan, E.-R. Kenawy,
S. S. Al-Deyab and A. Vinu, Microporous Mesoporous Mater.,
2010, 134, 87–92.
7 M. J. Earle, U. Hakala, C. Hardacre, J. Karkkainen,
B. J. McAuley, D. W. Rooney, K. R. Seddon,
J. M. Thompson and K. W ¨a h ¨a l ¨a , Chem. Commun., 2005,
903–906.
16
methanol. At the same time, Br ¨o nsted acid sites on Hb zeolites
will favor of the demethylation of anisole to produce phenol 3 as
4,31
a major intermediate, which will possibly react with octanoic
40
acid to produce phenyl octanoate 2. Moreover, the esterica-
tion of octanoic acid with methanol produces methyl octanoate
8 F. Zayed, L. Greiner, P. S. Schulz, A. Lapkin and W. Leitner,
Chem. Commun., 2008, 79–81.
16
4. According to the reaction data (Table 1), compound 2 and 4
are the two major byproducts and the better selectivity for p-OA
over Mix-Hb zeolite is mainly attributed to the decrease of them.
9 M. Kawamura, D. M. Cui, T. Hayashi and S. Shimada,
Tetrahedron Lett., 2003, 44, 7715–7717.
Thus, lower strength of Lewis acid sites and Br ¨o nsted acid sites 10 M. Kawamura, D. M. Cui and S. Shimada, Tetrahedron, 2006,
of Mix-Hb zeolite, as demonstrated by Py-IR, are advantageous 62, 9201–9209.
to suppress the demethylation of anisole and the subsequent 11 Y. Matsushita, K. Sugamoto and T. Matsui, Tetrahedron Lett.,
side reactions, accounting for its higher selectivity for p-OA in
2004, 45, 4723–4727.
this reaction.
12 D. Plazuk and J. Zakrzewski, J. Organomet. Chem., 2009, 694,
1
802–1806.
3 D. Plazuk and J. Zakrzewski, Synth. Commun., 2004, 34, 99–
07.
4 U. Hakala and K. W ¨a h ¨a l ¨a , Tetrahedron Lett., 2006, 47, 8375–
378.
5 A. E. W. Beers, T. A. Nijhuis, N. Aalders, F. Kapteijn and
J. A. Moulijn, Appl. Catal., A, 2003, 243, 237–250.
6 Y. D. Ma, Q. L. Wang, W. Jiang and B. J. Zuo, Appl. Catal., A,
1
1
1
1
4
. Conclusions
1
In conclusion, Friedel–Cras acylation of anisole with octanoic
acid over a novel Mix-Hb zeolite is rst established in this paper.
Noticeably, all factors in this reaction system including the
acylating agent, catalyst as well as the modifying agent are eco-
friendly. Modication by a mixed organic acid markedly
improved the catalytic performance of the parent Hb zeolite.
8
1997, 165, 199–206.
2
7
17 H. Yamashita, Y. Mitsukura and H. Kobashi, J. Mol. Catal. A:
Chem., 2010, 327, 80–86.
ICP and
Al MAS NMR results demonstrated the deal-
umination of the Hb zeolite under the mixed organic acid
treatment, promoting an increase in BET surface area and the
accessibility of reactants to the active sites, accounting for the
best catalytic performance of Mix-Hb zeolite. Moreover, lower
strength of Lewis acid sites and Br ¨o nsted acid sites of Mix-Hb
zeolite are advantageous to suppress the demethylation of ani-
sole and in turn accounts for its higher selectivity toward p-
octanoyl anisole.
18 S. G. Wagholikar, P. S. Niphadkar, S. Mayadevi and
S. Sivasanker, Appl. Catal., A, 2007, 317, 250–257.
19 G. Bond, J. A. Gardner, R. W. Mccabe and D. J. Shorrock,
J. Mol. Catal. A: Chem., 2007, 278, 1–5.
2
2
0 I. V. Kozhevnikov, Appl. Catal., A, 2003, 256, 3–18.
1 J. Kaur and I. V. Kozhevnikov, Chem. Commun., 2002, 2508–
2509.
22 H. Firouzabadi, N. Iranpoor and F. Nowrouzi, Tetrahedron
Lett., 2003, 44, 5343–5345.
Acknowledgements
23 H. Firouzabadi, N. Iranpoor and F. Nowrouzi, Tetrahedron,
004, 60, 10843–10850.
4 K. Shimizu, K. Niimi and A. Satsuma, Catal. Commun., 2008,
, 980–983.
5 C. Castro, J. Primo and A. Corma, J. Mol. Catal. A: Chem.,
002, 177, 273–280.
6 V. Mohan, C. Raghavendra, C. V. Pramod, B. D. Raju and
K. S. R. Rao, RSC Adv., 2014, 4, 9660–9668.
7 Z. X. Song, A. Takahashi, I. Nakamura and T. Fujitani, Appl.
Catal., A, 2010, 384, 201–205.
2
Financial support by the National Natural Science Foundation
of China (20806018 and 21376060) and the Natural Science
Foundation of Hebei Province (B2014201024) are gratefully
acknowledged.
2
2
2
2
9
2
Notes and references
1
E. Fillion and D. Fishlock, J. Am. Chem. Soc., 2005, 127,
3144–13145.
G. Y. Bai, Y. H. Yang, Z. Ma, J. Z. Xu, M. D. Qiu, F. He,
1
28 J. N. Park, J. Wang, S. I. Hong and C. W. Lee, Appl. Catal., A,
2005, 292, 68–75.
2
X. L. Yan and H. Y. Dou, Res. Chem. Intermed., 2012, 38, 29 R. Srivastava, N. Iwasa, S. I. Fujita and M. Arai, Catal. Lett.,
95–806.
2009, 130, 655–663.
A. Da ¸s tan, A. Kulkarni and B. T ¨o r ¨o k, Green Chem., 2012, 14, 30 G. Y. Bai, Z. Ma, L. J. Shi, X. W. Lan, Y. L. Wang, J. Han,
7
3
4
5
1
7–37.
M. D. Qiu, H. L. Fu and P. D. Liu, Appl. Catal., A, 2012,
427–428, 114–118.
A. E. W. Beers, T. A. Nijhuis, F. Kapteijn and J. A. Moulijn,
Microporous Mesoporous Mater., 2001, 48, 279–284.
31 A. E. W. Beers, J. A. Bokhoven, K. M. Lathouder, F. Kapteijn
and A. Moulijn, J. Catal., 2003, 218, 239–248.
M. Bejblov ´a , D. Proch ´a zkov ´a and J. Cejka, ChemSusChem,
ˇ
2009, 2, 486–499.
27120 | RSC Adv., 2014, 4, 27116–27121
This journal is © The Royal Society of Chemistry 2014

View Article Online
Paper
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3
2 L. R. Aramburo and L. Karwacki, Chem.–Eur. J., 2011, 17, 36 Z. K. Zhang, S. L. Liu, X. X. Zhu, Q. X. Wang and L. Y. Xu, Fuel
3773–13781. Process. Technol., 2008, 89, 103–110.
3 Z. M. Yan, D. Ma, J. Q. Zhuang, X. C. Liu, X. M. Liu, 37 X. X. Guan, N. Li, G. J. Wu, J. X. Chen, F. X. Zhang and
1
3
X. W. Han, X. H. Bao, F. X. Chang, L. Xu and Z. M. liu, J.
Mol. Catal. A: Chem., 2003, 194, 153–167.
N. J. Guan, J. Mol. Catal. A: Chem., 2006, 248, 220–225.
38 A. K. Pandey and A. P. Singh, Catal. Lett., 1997, 44, 129–133.
3
4 N. Narender, K. V. V. K. Mohan, S. J. Kulkarni and 39 A. P. Singh and A. K. Pandey, J. Mol. Catal. A: Chem., 1997,
I. A. K. Reddy, Catal. Commun., 2006, 7, 583–588. 123, 141–147.
5 M. Ghiaci, A. Abbaspur, R. Kia, C. Belver, R. Trujillano, 40 A. Prabhu, L. Kumaresan, M. Palanichamy and
V. Rives and M. A. Vicente, Catal. Commun., 2007, 8, 49–56. V. Murugesan, Appl. Catal., A, 2009, 360, 59–65.
3
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