H3PW12O40/mpg-C3N4 as an efficient and reusable catalyst in the alkylation of o-xylene and styrene

Article abstract of DOI:10.1002/aoc.5129

A heterogeneous catalyst (HPW/mpg-C₃N₄) for the alkylation of o-xylene and styrene reaction was acquired by the immobilization of phosphotungstic acid (HPW) on mesoporous graphitic carbon nitride (mpg-C₃N₄) through electrostatic interaction. The results of Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA) proved that HPW was successfully immobilized on the protonated mpg-C₃N₄ by electrostatic interaction. The textural properties and morphology of HPW/mpg-C₃N₄ were characterized by N₂ adsorption–desorption, scanning electron microscopy (SEM). Among them, 40% HPW/mpg-C₃N₄ displays the best catalytic performance in the alkylation reaction with 91.8% yield and 96.5% selectivity to 1, 2-diphenylethylane. Moreover, protonated mpg-C₃N₄ not only displays as a support to facilitate great dispersion of HPW but also promotes the alkylation product diffusion effectively. Besides, the HPW/mpg-C₃N₄ catalyst could be recycled easily without significant loss of catalytic activity, which is demonstrate by the recyclability of HPW/mpg-C₃N₄ catalyst test.

Full text of DOI:10.1002/aoc.5129

Received: 18 December 2018
DOI: 10.1002/aoc.5129
Revised: 18 June 2019
Accepted: 28 June 2019
F U L L P A P E R
H3PW12O40/mpg‐C3N4 as an efficient and reusable catalyst
in the alkylation of o‐xylene and styrene
Zhiying Zhu
Yonghui Liu
| Beibei Wang
| Qingzhao Yao | Yuming Zhou | Haiyong Yang |
School of Chemistry and Chemical
Engineering, Southeast University,
Nanjing 211189, P. R. China
A heterogeneous catalyst (HPW/mpg‐C3N4) for the alkylation of o‐xylene and
styrene reaction was acquired by the immobilization of phosphotungstic acid
(HPW) on mesoporous graphitic carbon nitride (mpg‐C3N4) through electro-
static interaction. The results of Fourier transform infrared spectroscopy (FT‐
IR), X‐ray powder diffraction (XRD), X‐ray photoelectron spectroscopy (XPS)
and thermogravimetric analysis (TGA) proved that HPW was successfully
immobilized on the protonated mpg‐C3N4 by electrostatic interaction. The tex-
tural properties and morphology of HPW/mpg‐C3N4 were characterized by N2
adsorption–desorption, scanning electron microscopy (SEM). Among them,
40% HPW/mpg‐C3N4 displays the best catalytic performance in the alkylation
reaction with 91.8% yield and 96.5% selectivity to 1, 2‐diphenylethylane. More-
over, protonated mpg‐C3N4 not only displays as a support to facilitate great dis-
persion of HPW but also promotes the alkylation product diffusion effectively.
Besides, the HPW/mpg‐C3N4 catalyst could be recycled easily without signifi-
cant loss of catalytic activity, which is demonstrate by the recyclability of
HPW/mpg‐C3N4 catalyst test.
Correspondence
Yuming Zhou and Qingzhao Yao School
of Chemistry and Chemical Engineering,
Southeast University, Nanjing, 211189, P.
R. China.
Email: 101006377@seu.edu.cn;
fchem@163.com
Funding information
Transformation of Scientific and Techno-
logical Achievements of Jiangsu Province
of China, Grant/Award Number:
BA2016105; Priority Academic Program
Development of Jiangsu Higher Education
Institutions (PADA), Grant/Award Num-
ber: 1107047002; Scientific Innovation
Research Foundation of College Graduate
in Jiangsu Province, Grant/Award Num-
ber: KYLX16‐0266; Fundamental
Research Funds for the Central Universi-
ties, Grant/Award Number:
KEYWORDS
alkylation, mesoporous catalyst, mpg‐C3N4
2242018 k30008; Prospective Joint
Research Project of Jiangsu Province,
Grant/Award Number: BY2016076‐01;
Natural Science Foundation of Jiangsu
Province, Grant/Award Number:
BK20171357; National Nature Science
Foundation of China, Grant/Award
Numbers: 21376051, 21676056 and
51673040
1 | INTRODUCTION
mesoporous zirconia, displayed high catalytic activity to
different reactions under mild conditions.[1–5] The highly
As we all known, there are many efficient catalysts in
nature, the catalysts that are capable of achieving com-
plex reactions through sophisticated strategies. Different
catalysts, such as graphitic carbon nitride, meta – organic
frameworks, polyoxometalate intercalated layered double
hydroxide composite materials and amine‐functionalized
efficient catalytic abilities of catalysts are due to coopera-
tive interactions between exactly positioned functional
groups present in their active sites.[6,7] The design of
cooperative catalytic systems can be accomplished, which
can through a well‐ordered multi‐functionalization of
inorganic supports such as mesoporous silica and
Appl Organometal Chem. 2019;e5129.
wileyonlinelibrary.com/journal/aoc
© 2019 John Wiley & Sons, Ltd.
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https://doi.org/10.1002/aoc.5129

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ZHU ET AL.
graphitic carbon nitride.[8–10] In addition, the inorganic
porous supports can carry different and often incompati-
ble catalytic functions separated at appropriate molecular
distances, for example, acids and bases provide site isola-
tion within the inorganic network.[11] In most cases,
space isolation of incompatible active organic groups that
cannot coexist in solution is the key to prepare functional
heterogeneous hybrid catalysts.[12,13] For one thing, more
than half of chemical conversion synthetic materials
involve at least one catalytic step in the process of their
synthesis.[14] It is essential to improve the efficiency of
catalyst, increases product yields, reduces the number
and quantity of unwanted by‐products, or lowers the
energy and cost involved in several industrial catalytic
processes.[15–17] For another, mesoporous materials,
which are synthesized by supramolecular self‐assembly
of various metal oxide precursors, have been effectively
used as solid supports or carrier of various catalytic
groups attribute to their well‐controlled nanometer pore
structures and extremely high surface area.[18–20] For
instance, by introducing a variety of organic groups
including catalytically active sites such as acids, bases,
organometallic complexes, and chiral auxiliary ligands
into their nanometer pores, varieties of solid‐state, recy-
clable, high surface area supported mesoporous catalysts
for a great deal of reactions have been synthesized.[21–24]
Graphitic carbon nitride (g‐C3N4) is consisted of a huge
number of nitrogen atoms with potential base functional-
ity (terminal amino groups ‐NH2 and bridging N atoms ‐
N‐).[25] As a metal‐free semiconductor, graphitic carbon
nitride (g‐C3N4) materials have attracted extensive atten-
tion in the last years because of their unique chemical,
electronic and (photo) catalytic properties.[26,27] The latter
depends on the size, morphology, surface area, dispersion,
light absorption and ability to efficiently separate
charges.[28,29] However, C3N4, which usually has a limited
surface area, is difficulty to disperse in solvents and rather
low photocatalytic activity, if synthesized via traditional
routes from simple monomers (cyanamide, melamine,
dicyandiamide or urea), the synthesis route is complex
and the yield is low.[30] Over the past few years, there are
several templating ways alongside the insertion of other
heteroatoms into C3N4 structure were recommended for
purpose of advance its performance, such as combining
with other semiconductors to found composite
photocatalysts, element doping and morphological modi-
fication, among which doping with other elements is a
characteristic method, such as the Zn,[31] Ag,[32] Fe[33]
doped g‐C3N4 had been structured and got enormous
strides ahead. Because of their distinct structural, physical
and chemical properties, hollow structures proved espe-
cially effectively activity in the area of photo and heteroge-
neous catalysis and could also acquire potential
applications in drug delivery, catalysis, gas storage, lith-
ium batteries and nanodevices.[34,35] Currently, the only
way to synthesize metal‐free hollow structures is to use
soft and hard templating methods. Nevertheless, despite
recent progress, the traditional template approaches has
gained a wide variety of structures, but they still require
multiple steps and are considered complex and time‐
consuming. Besides, the templates are usually removed
by strong acid/base treatment, which can destroy the
organic material. Up to date, the advantages of CM[36]
supramolecular polymers that were precipitated from
diverse solvents as the precursors for well‐ordered C3N4
with controllable chemical and photophysical properties
are proved.[37,38] However, in contrast to the ever‐
expanding families of metal complex catalysts, the catalyt-
ically active hybrid mesoporous materials prepared with
this elegant method are rather limited.[39] In view of the
above, with the exception of the large surface area and
plentiful mesopores, mesoporous graphitic carbon nitride
(mpg‐C3N4) has more nitrogen as active sites, which can
be used as anchors for HPW and displays great catalytic
performance in alkylation of o‐xylene and styrene.[40]
Polyoxometalates (POMs),[41,42] peculiarly phosphotung-
stic acid (H3PW12O40, HPW), as a result of their adminis-
trable redox and acidic properties, which have been used
as available catalysts in oxidation and alkylation reac-
tion.[43] Whereas, HPW has a low specific surface area
and generally cannot be recovered because of its solubility
in multiple polar solvents, besides, it causing hardness in
separation and recycling, which could be limits its utiliza-
tion.[44] Consequently, there is an imperative to develop
recyclable POM based catalysts for practical applica-
tions.[45] Varieties of strategies for immobilization of
HPW on carries have been developed containing embed-
ding HPW into a metal–organic framework, adsorption
on activated carbon and electrostatic attachment to qua-
ternary ammonium functionalized chloromethylated
polystyrene, amine‐grafted graphene oxide, exfoliated
montmorillonite and carbon nitride materials, covalently
grafted POM on mesoporous hybrid silicas and SBA‐
15.[46,47] Up to date, electrostatic attachment of HPW to
positively charged supports are the most developed and
widely used technique. Recently, they prepared a series
of HPW/mpg‐C3N4 catalysts by simple method, which
showed excellent activity and selectivity in alkylation
reactions.[48] Driven by such advantages, they synthesized
a periodic mesoporous hybrid material containing a rho-
dium organophosphine complex in the framework.[49,50]
In this work, HPW was immobilized on protonated
mpg‐C3N4 via electrostatic interaction and used as a cata-
lyst in the alkylation of o‐xylene and styrene reaction.
Because of its controllable redox and acidic properties,
HPW can efficiently catalyze the alkylation of o‐xylene

ZHU ET AL.
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and styrene reaction. Additionally, mpg‐C3N4 not only
acts as a support but also promotes the alkylation effec-
tively. HPW/mpg‐C3N4 as a heterogeneous catalyst can
be easily recovered and reused without obvious deteriora-
tion in its structural integrity and activity.
pore size distributions were carried out by Brunauer–
Emmett–Teller (BET) method at −196 °C under an ASAP
2020 system. Fourier transform infrared (FT‐IR) spectra
were recorded on a BRUKERALPHA FT‐IR spectrometer.
FT‐IR spectrophotometer using anhydrous KBr as stan-
dard (1 wt% of the sample). Thermogravimetric Analysis
(TGA) was performed using a Rigaku ThermoPlus
TG8120 system at a rate of 10 °C min−1 under air. The
X‐ray photoelectron spectroscopy (XPS) spectra were per-
formed on a Thermo ESCALAB 250 with Al Kα radiation.
2 | EXPERIMENTAL
2.1 | Materials
All chemicals were analytical grade and were used as
received without further purification. Melamine, cyanuric
acid, dimethyl sulfoxide (DMSO) and Phosphotungstic
acid (HPW) were all purchased from Sinopharm Chemi-
cal Reagent Co. Ltd.
2.4 | Catalyic tests
The alkylation reactions were carried out in a continu-
ously stirred batch reactor under reflux conditions using
a three‐neck 100 ml round‐bottom flask equipped with a
condenser. Preliminary runs were conducted with 4.0 g
(0.03841 mol) of styrene, 30.0 g (0.2826 mol) of o‐xylene
(quality ratio of o‐xylene to styrene, 7.5:1) and 0.30 g of
catalyst at 120 °C for 180 min. The required amount of
o‐xylene was initially added to the reactor at the reaction
temperature, followed by the desired amount of catalyst,
a known amount of styrene was then added to the reac-
tion mixture at the same temperature. After the reaction,
unreacted o‐xylene was distilled out under atmospheric
pressure and then a collected part was called as crude
product. The crude product was analyzed with GC‐
9890A gas chromatograph equipped with OV‐1 capillary
column and a flame ionization detector (FID). The yield
of PXE was defined as follows:
2.2 | Catalyst synthesis
2.2.1 | Preparation of mpg‐C3N4
Carbon nitride porous hollow spheres prepared according
to a method described by Yang et al.[51] In a typical syn-
thesis, 0.5 g melamine and 0.5 g cyanuric acid were dis-
solved in 20 ml and 10 ml DMSO, respectively. Then
melamine solution was added to cyanuric acid solution,
and the mixture was stirred for 1 hr and centrifuged.
The white precipitates were washed with water and etha-
nol several times and dried at 60 °C for 24 hr. Finally, the
powders were heated to 550 °C for 4 hr under a flow of
nitrogen with a heating rate of 2.3 °C min−1. The final
products were named mpg‐C3N4.
Yield of PXE (%) = actual product weight/theoretical
product weight*100%.
actual product weight = crude product weight*PXE
(chromatography) % (1)
2.2.2 | Synthesis of xHPW/mpg‐C3N4
HPW/mpg‐C3N4 was prepared by impregnation accord-
ing to the approach reported in the literature[52] with a
slight modification. In a typical procedure, a certain
amount of HPW was dissolved in 50 ml anhydrous etha-
nol, then 1.0 g mpg‐C3N4 was added to HPW solution.
After 10 mins ultrasound, the dispersion was stirred for
24 hr at 50 °C, the resulting catalyst was obtained. The
final samples were denoted as xHPW/mpg‐C3N4 (where
‘x’ means the weight percentage of HPW in the sample).
3 | RESULTS AND DISCUSSION
3.1 | Catalyst characterization
3.1.1 | Fourier transform infrared spec-
troscopy (FT‐IR) analysis
The FT‐IR spectra of mpg‐C3N4, HPW and HPW/mpg‐
C3N4 are presented in Figure 1. The typical band of
mpg‐C3N4 shows a framework band at 808 cm−1, which
corresponds to the representative mode of the triazine
units. The band at 1641 cm−1 is related with a C=N
stretching vibration mode, while the bands at 1243 cm
−1, 1318 cm−1 and 1405 cm−1 are ascribed to aromatic
C‐N stretching. The characteristic spectrum of HPW with
a Keggin structure is 1077 cm−1, while is assigned to the
asymmetric vibrations of the P‐O of tetrahedral PO4,
2.3 | Catalyst characterization
Phase composition of the obtained samples were ana-
lyzed using X‐ray diffractometer RINTUltima III (Rigaku)
with Cu Kα radiation: 40 kV and 200 mA. Scanning elec-
tron microscopy (SEM) images were recorded on a JEOL
JSM‐5600 L SEM instrument. Specific surface areas and

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ZHU ET AL.
FIGURE 1 FT‐IR spectra (left) and partial enlarged details (right) of HPW (a), mpg‐C3N4(b), 20% HPW/mpg‐C3N4 (c), 30% HPW/mpg‐
C3N4 (d), 40% HPW/mpg‐C3N4(e) and 50% HPW/mpg‐C3N4 (f)
and the bands at 985 cm−1, 892 cm−1 and 807 cm−1 are
attributed to the stretching modes of the terminal W=O,
respectively. It was obviously observed of these typical
bands of the Keggin structure in the FT‐IR spectrum of
HPW/mpg‐C3N4. Besides, there is a slightly red‐shift
(1079 cm−1 to 1077 cm−1, 892 cm−1 to 890 cm−1) between
the representative bands of HPW in the FT‐IR spectrum
of HPW/mpg‐C3N4 and those of HPW, suggesting a tough
interaction between [PW12O40]3− and mpg‐C3N4. The
results of FT‐IR show that HPW could be immobilized
on mpg‐C3N4.
For HPW, the diffraction peaks at 2θ (in degrees) of 9–
11°, 18–21°, 25–30° and 34–40° are typical of HPW with a
Keggin structure have ever reported in previous litera-
ture.[53] For mpg‐C3N4, the tough peak located at 26.7° is
contributed to the interlayer stacking (002) peak of the aro-
matic segments of the carbon nitride sheets. Furthermore,
there is a low‐angle reflection at 10.6° is linked to the (100)
plane, which is a smaller in‐planar distance than one tri‐s‐
triazine unit, probably initiated from the in‐planar tri‐s‐
triazine units with a small tilt angularity to the main layers.
As can be seen, the XRD patterns of HPW/mpg‐C3N4,
which intensity of the mpg‐C3N4 characteristic peak at
26.5° diminished gradually and the intensity of the HPW‐
related peak at 26.2° increase gradually with an increase
in HPW loading (20–50%). The results of typical peaks of
HPW in the XRD patterns of HPW/mpg‐C3N4 suggested
that HPW was successfully immobilized on the mpg‐
C3N4 and its structure was well preserved.
3.1.2 | X‐ray powder diffraction (XRD)
analysis
Figure 2 shows the XRD patterns of mpg‐C3N4 and
HPW/mpg‐C3N4 with different HPW loadings (20–50%).
3.1.3 | X‐ray photoelectron spectroscopy
(XPS) analysis
XPS was carried out to analyze the composition and
valence states of the elements in the 40% HPW/mpg‐C3N4
(Figure 3). The results of XPS wide scan spectrum shows
that 40% HPW/mpg‐C3N4 is composed of P, W, O, C and
N. The C 1 s spectrum can be observed three peaks at
288.3 eV, 285.1 eV and 284.3 eV, which was appointed
to the pure graphitic sites in the CN matrix (C‐C), sp2‐
bonded to N inside the s‐triazine units (N=C‐N) and sp2
C atoms bonded to aliphatic amine in the aromatic rings
(N=C(‐N)‐N), respectively. Besides, the N 1 s spectrum
can be acquired four peaks at 403.8 eV, 400.3 eV,
399.4 eV and 398.7 eV, suggesting four types of N with
different bonding states on the surface of g‐C3N4. Fur-
thermore, the three peaks of 398.3 eV, 399.9 eV and
FIGURE 2 XRD patterns of mpg‐C3N4 (a), 20% HPW/mpg‐C3N4
(b), 30% HPW/mpg‐C3N4 (c), 40% HPW/mpg‐C3N4 (d) and 50%
HPW/mpg‐C3N4 (e)

ZHU ET AL.
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FIGURE 3 XPS wide scan spectra of 40% HPW/mpg‐C3N4 (A) and P 2p, W 4f, C 1 s and N 1 s XPS spectra of 40% HPW/mpg‐C3N4 (B‐E)
401.3 eV are characteristic to the sp2‐bonded aromatic N
in the triazine units (C‐N=C), the bridging N bonding
to carbon atoms (N‐(C)3 or C‐N(‐H)‐C) and the terminal
amino groups (C‐NH2) due to incomplete condensation
individually. The peak at 403.8 eV is caused to the posi-
tive charge effect in the heterocycles due to a tiny amount
of protonated N of mpg‐C3N4. The P 2p spectrum
displayed a wide signal peak at about 133.8 eV, ascribing
the existence of P5+ in the oxidation state. Additionally,
the W 4f spectrum is deconvoluted into two vital peaks
at 35.1 eV (4f5/2) and 37.2 eV (4f7/2), respectively, which
are typically attributed to W in the W‐O bond configura-
tion and W6+ in HPW. Combining XPS spectrum of P2p
and W4f, it can be demonstrate Keggin structure of 12‐
tungstophosphoric acid was loaded in the channels
successfully. The results were corresponding with FT‐IR
and XRD of HPW/mpg‐C3N4.
3.1.4 | Thermogravimetric analysis (TGA)
The TGA curves of HPW, HPW/mpg‐C3N4 (20–50%) and
mpg‐C3N4 are display in Figure 4. As can be seen, HPW
was subjected to three steps of mass loss on TGA. The
first loss of 5.9% between 23 °C and 110 °C is due to the
weight loss of physically absorbed water. The second step
is a loss of 5.6% between 110 °C and 260 °C as a result of
the weight loss of structural water, while the third step is
a loss of 0.9% at approximately 580 °C results from the
loss of acidic protons and the decomposition of the

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ZHU ET AL.
40% HPW/mpg‐C3N4 and 50% HPW/mpg‐C3N4 are
shown in Figure 5. From Figure 5 (left), the all samples
show a type‐IV curve with a wide capillary condensation
step at p/p0 of 0.8–1.0, indicating the porous structure of
the sample. The weight percentage of HPW in the sample
had a significant influence on BET surface area and aver-
age pore size from Table 1. With the weight percentage of
HPW from 20% to 50%, the BET surface area of mpg‐C3N4
from 101 m2/g decrease to 55m2/g, correspondingly, the
pore volume of each sample decrease gradually. This is
due to the collapse of some of the pores during the treat-
ment of phosphotungstic acid. Pore size distribution of
the samples is shown in Figure 5 (right), to be exact, the
channels size of HPW/mpg‐C3N4 between 20–50 nm,
which suggests that the mesoporous structure of mpg‐
C3N4 can be preserved even after immobilization of
HPW. Therefore, because of its larger surface area and
porosity, HPW/mpg‐C3N4 is prospective to show great
catalytic performance in the tandem reaction.
FIGURE 4 TGA analysis of HPW (a), 50% HPW/mpg‐C3N4 (b),
40% HPW/mpg‐C3N4 (c), 30% HPW/mpg‐C3N4 (d), 20% HPW/
mpg‐C3N4 (e) and mpg‐C3N4 (f)
Keggin structure. Mpg‐C3N4 was experienced two steps of
mass loss on TGA, a first weight loss of 9.3% up to 330 °C
is attribute to the removal of adsorbed water, and second
weight loss of 89.1% between 330 °C and 685 °C is
because of the direct thermal dissolution of mpg‐C3N4.
According to the TGA curves, the results also show that
HPW/mpg‐C3N4 (20%, 30%, 40% and 50%) has brilliant
chemical stability from 20 to 420 °C. From the above
results, the practical HPW loadings in HPW/mpg‐C3N4
are about 16.3%, 25.1%, 34.6% and 44.0%, respectively,
which are similar to the corresponding theoretical values
of 20%, 30%, 40% and 50%, respectively.
3.1.6 | Scanning electron microscopy
(SEM) analysis
The morphologies of precursor‐C3N4, mpg‐C3N4 and 40%
HPW/mpg‐C3N4 were shown in Figure 6. As expected,
TABLE 1 Physicochemical properties of the HPW/mpg‐C3N4
BET
Surface
Area (m2/g)
Pore
Volume
(cm3/g)
Average
Pore
Size (nm)
Sample
Name
CN
126
101
82
0.60
0.58
0.72
0.66
0.28
37.02
34.67
35.21
35.19
33.11
3.1.5 | Brunauer–Emmett–teller (BET)
20%
30%
40%
50%
analysis
The N2 adsorption–desorption isotherms and the corre-
sponding pore size distribution curves (PSD curves) of
mpg‐C3N4, 20% HPW/mpg‐C3N4, 30% HPW/mpg‐C3N4,
77
55
FIGURE 5 N2 adsorption–desorption isotherms of mpg‐C3N4 (a), 20% HPW/mpg‐C3N4 (b), 30% HPW/mpg‐C3N4 (c), 40% HPW/mpg‐
C3N4 (d) and 50% HPW/mpg‐C3N4 (e) (left), pore size distributions (right)

ZHU ET AL.
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FIGURE 6 SEM images of precursor‐C3N4 (A), mpg‐C3N4 (B) and 40% HPW/mpg‐C3N4 (C)
the SEM image of precursor‐C3N4 displays sphere‐like
particles with holes on the surface (Figure 6 A), while
mpg‐C3N4 shows a tortile flake‐like texture and resulted
almost in a full preservation of the starting spherical mor-
phology even after calcination at high temperatures
(Figure 6 B). Figure 6 C shows the SEM image of 40%
HPW/mpg‐C3N4, in which the mpg‐C3N4 sheets are
shaggy with a number of wrinkles, which may be because
of the changes in the morphology of mpg‐C3N4 by proton-
ation. Moreover, there is no HPW aggregation on the
mpg‐C3N4 surface, which demonstrated the stability of
the catalyst.
can be obviously seen that Phosphotungstic acid possess
excellent activities both yield (98.3%) and selectivity
(98.3%) for this reaction, it's consistent with expected
result. However, the product is difficult to purify. Addi-
tionally, the dual‐mesoporous supports themselves show
chemical inertia in the alkylation process because of their
lack of acidic sites. Moreover, the HPW/mpg‐C3N4 pos-
sessed multiple advantages, such as strong acidity, high
specific surface area, easy to recycle, etc. Furthermore,
compared with a pure HPW, this catalyst was simply sep-
arated from the mixture. As shown in Table 2, it can be
clearly seen that all catalysts possess high PXE yield and
good selectivity, indicating that HPW/mpg‐C3N4 catalyst
was prepared successfully via anion exchange with
HPW. Among them, 40% HPW/mpg‐C3N4 shows the
highest product yield (91.8%) and best selectivity
(96.5%). The excellent catalytic performance of 40%
HPW/mpg‐C3N4 is due to both the appropriate pore
structure and strong acid sites distribution.
3.2 | Catalytic performance evaluation
3.2.1 | Activity of various supported
HPW/mpg‐C3N4catalysts
The catalytic activity of HPW/mpg‐C3N4 was proved in
the alkylation of styrene with o‐xylene (scheme 1) and
the results were shown in Table 2. From the table, it
3.2.2 | Recyclability of HPW/mpg‐C3N4
catalyst
In addition to the thermal stability shown by TGA, the
recovery and utilization of catalyst may be another effec-
tive method to judge the performance of catalyst.
Although the activity of catalyst showed good perfor-
mance in the alkylation of o‐xylene and styrene, which
can be demonstrated by both the styrene conversion rate
(%) and 1, 2‐diphenylethylane yield (%), stability still
needs to be considered. The cyclicity of the catalyst
HPW/mpg‐C3N4 has been tested by the reaction with
used catalyst under the optimized conditions. After each
reaction, the catalyst was recovered by filtration, then
centrifuged, washed with ethanol, dried at 60 °C over-
night and used again. The summary of resulting data is
summarized in Figure 7. It is important to note that the
recovery of the catalyst is not as stable as we expected.
Take the HPW/mpg‐C3N4 as an example, it can be seen
5.6% reduction in the activity is observed after 5 runs
for the catalyst. The catalytic stability of HPW/mpg‐
SCHEME
heterogeneous catalyst.
1
Reaction of o‐xylene with styrene over a
TABLE 2 Activity of various supported HPW/mpg‐C3N4 catalysts
Catalyst
Yield (%)
Selectivity (%)
HPW
98.3
80.3
82.7
91.8
87.1
98.3
88.7
90.5
96.5
94.1
20% HPW/mpg‐C3N4
30% HPW/mpg‐C3N4
40% HPW/mpg‐C3N4
50% HPW/mpg‐C3N4
Reaction conditions: o‐xylene: styrene = 7.5:1, reaction temperature = 393 K
reaction time = 3.0 hr

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ZHU ET AL.
Jiangsu Province (BY2016076‐01), the Fundamental
Research Funds for the Central Universities
(2242018 k30008), Scientific Innovation Research Foun-
dation of College Graduate in Jiangsu Province
(KYLX16‐0266), a Project Funded by the Priority Aca-
demic Program Development of Jiangsu Higher Educa-
tion Institutions (PADA) (1107047002), Fund Project for
Transformation of Scientific and Technological Achieve-
ments of Jiangsu Province of China (BA2016105).
CONFLICT OF INTEREST
There are no conflicts of interest to declare.
ORCID
FIGURE 7 Catalytic stability of the 40% HPW/mpg‐C3N4
catalyst in the alkylation of o‐xylene with styrene. Reaction
conditions: o‐xylene: styrene = 7.5: 1, reaction temperature = 393 K,
reaction time = 3.0 hr
Zhiying Zhu https://orcid.org/0000-0001-9606-1833
Beibei Wang https://orcid.org/0000-0001-6550-1074
REFERENCES
C3N4 decreased, which may be because of the possibility
that HPW leached from the catalyst carrier into the liquid
reaction system resulting in the loss of acidic site. How-
ever, there is also a great catalytic performance after 5
runs compared with others similar catalyst.
[1] L. C. Lee, J. Lu, M. Weck, C. W. Jones, ACS Catal. 2016, 6, 784.
[2] G. B. Varadwaj, S. Rana, K. M. Parida, Dalton Trans. 2013, 42,
5122.
[3] H. Fu, C. Qin, Y. Lu, Z. M. Zhang, Y. G. Li, Z. M. Su, W. L. Li,
E. B. Wang, Angew. Chemie 2012, 51, 7985.
[4] D. Wang, Z. H. Li, Catal. Sci. Technol. 2015, 5, 1623.
4 | CONCLUSIONS
[5] W. J. Ang, Y. S. Chng, Y. L. Lam, RSC Adv. 2015, 5, 81415.
[6] Y. Leng, P. P. Zhao, M. J. Zhang, J. Wang, J. Mol. Catal. A:
Chem. 2012, 358, 67.
An efficient and reusable catalyst HPW/mpg‐C3N4 with
different HPW loadings was prepared by a facile impreg-
nation method through electrostatic interaction between
HPW and protonated mpg‐C3N4. According to the results
of performance evaluation, 40% HPW/mpg‐C3N4 has
excellent catalytic performance in the alkylation reaction
for styrene. The high catalytic performance of 40%
HPW/mpg‐C3N4 (91.8% yield and 96.5% selectivity to
1,2‐diphenylethylane), which is attributed to the excellent
catalytic performance of HPW in the alkylation reaction,
respectively. Contemporaneously, the great catalytic per-
formance is also due to the excellent dispersion of HPW
over mpg‐C3N4 and the cooperative effects of HPW and
mpg‐C3N4 for the alkylation reaction. What's more, the
current approach supplies a hopeful and widespread
strategy for the construction of hybrid catalysts based on
HPW and mesoporous materials for alkylation reaction.
[7] H. H. Zhao, N. Y. Yu, J. Q. Wang, D. Y. Zhuang, Y. Ding, R.
Tan, D. H. Yin, Microporous Mesoporous Mater. 2009, 122, 240.
[8] V. N. Panchenko, M. M. Matrosova, J. Jeon, J. W. Jun, M. N.
Timofeeva, S. H. Jhung, J. Catal. 2014, 316, 251.
[9] F. Z. Su, M. Antoniettia, X. C. Wang, Catal. Sci. Technol. 2012,
2, 1005.
[10] J. J. Wua, N. Lia, H. B. Fanga, X. T. Lia, Y. Z. Zheng, X. Tao,
Chem. Eng. J. 2019, 358, 20.
[11] E. Gianotti, U. Diaz, A. Veltya, A. Corma, Catal. Sci. Technol.
2013, 326, 77.
[12] J. W. Sun, Y. S. Fu, G. Y. He, X. Q. Sun, X. Wang, Appl. Catal.
B: Environ. 2015, 165, 661.
[13] H. W. Huang, R. R. Cao, S. X. Yu, K. Xu, W. C. Hao, Appl.
Catal. B: Environ. 2017, 219, 526.
[14] J. Xu, K. Shen, B. Xue, Y. X. Li, J. Mol. Catal. A: Chem. 2013,
372, 105.
[15] G. Postole, B. Chowdhury, B. Karmakar, K. Pinki, J. Banerji, A.
Auroux, J. Catal. 2010, 269, 110.
[16] A. Dhakshinamoorthy, M. Opanasenko, H. Garcia, Catal. Sci.
Technol. 2013, 3, 2509.
ACKNOWLEDGEMENTS
This work was supported by the National Nature Science
Foundation of China (51673040, 21676056 and 21376051),
the Natural Science Foundation of Jiangsu Province
(BK20171357), the Prospective Joint Research Project of
[17] K. K. Sharma, R. P. Buckley, T. Asefa, Langmuir 2008, 24,
14306.
[18] Q. G. Han, F. Zhao, C. G. Hu, L. X. Lv, Z. P. Zhang, N. Chen, L.
T. Qu, Nano Res. 2015, 8, 1718.

ZHU ET AL.
9 of 9
[19] R. Fei, L. Yang, Nano Lett. 2014, 14, 2884.
[39] Z. Zhu, X. Tang, Y. S. Yan, Appl. Catal. B: Environ. 2019, 241,
319.
[20] A. G. Slater, L. M. Perdigao, P. H. Beton, N. R. Champness, Acc.
Chem. Res. 2014, 47, 3417.
[40] J. Xu, Y. Wang, J. K. Shang, Q. Jiang, Y. X. Li, Catal. Sci.
Technol. 2016, 6, 4192.
[21] Y. Z. Hong, C. S. Li, Z. Y. Fang, B. F. Luo, W. D. Shi, Carbon
2017, 121, 463.
[41] F. J. Ma, S. X. Liu, C. Y. Sun, D. D. Liang, G. J. Ren, F. Wei, Y.
G. Chen, Z. M. Su, J. Am. Chem. Soc. 2011, 133, 4178.
[22] J. W. Sun, J. S. Xu, A. Grafmueller, X. Huang, C. Liedel, G. A.
Siller, M. Willinger, C. Yang, Y. S. Fu, X. Wang, Appl. Catal. B:
Environ. 2017, 205, 1.
[42] M. B. Ansari, H. L. Jin, M. N. Parvin, S. E. Park, Catal. Today
2012, 185, 211.
[23] X. B. Shao, X. K. Jiang, S. Z. Zhu, Z. T. Li, Tetrahedron 2004, 60,
[43] C. Yvon, A. J. Surman, M. Hutin, J. Alex, B. O. Smith, D. L.
9155.
Long, L. Cronin, Angew. Chemie 2014, 3336.
[24] H. Q. Yang, G. Li, Z. C. Ma, J. B. Chao, Z. Q. Guo, J. Catal.
2010, 276, 123.
[44] Y. J. Chen, R. Tan, W. G. Zheng, D. G. Yin, Catal. Sci. Technol.
2014, 4, 4084.
[25] X. Wang, K. Maeda, A. Thomas, K. Takanabe, G. Xin, J. M.
[45] N. Essayem, A. Holmqvist, P. Y. Gayraud, J. C. Vedrine, Y. B.
Carlsson, K. Domen, M. Antonietti, Nature Mater. 2009, 8, 76.
TaaritIn, J. Catal. 2001, 197, 273.
[26] D. D. Tang, G. K. Zhang, Appl. Surf. Sci. 2017, 391, 415.
[46] L. Yang, Y. T. Qi, X. X. Yuan, J. Mol. Catal. A: Chem. 2005, 229,
199.
[27] Z. Zhu, W. Q. Fan, Z. Liu, H. Dong, Y. Yan, J. Photoch.
Photobio. A. 2018, 359, 102.
[47] R. Tan, C. Liu, A. Zheng, D. H. Yin, Microporous and Mesopo-
rous Mater. 2012, 158, 77.
[28] F. L. Wang, P. Chen, F. L. Wang, Appl. Catal. B: Environ. 2017,
207, 103.
[48] D. L. Long, E. Burkholder, L. Cronin, Chem. Soc. Rev. 2007, 36,
105.
[29] H. Q. Li, Y. X. Liu, X. Gao, C. Fu, X. C. Wang, ChemSusChem
2015, 8, 1189.
[49] Y. Leng, J. Wang, D. R. Zhu, Green Chem. 2011, 13, 1636.
[30] C. Han, Y. D. Wang, Y. P. Lei, B. Wang, N. Wu, Q. Shi, Q. Li,
[50] B. Nohra, H. El Moll, L. M. Rodriguez Albelo, P. Mialane, J.
Marrot, C. Mellot‐Draznieks, M. O'Keeffe, R. Ngo Biboum, J.
Lemaire, B. Keita, L. Nadjo, A. Dolbecq, J. Am. Chem. Soc.
2011, 133, 13363.
Nano Res. 2015, 8, 1199.
[31] C. Chang, Y. Fu, M. Hu, C. Y. Wang, G. Q. Shan, L. Y. Zhu,
Appl. Catal. B: Environ. 2013, 142, 5.
[51] H. Y. Yang, Y. M. Zhou, J. Mater. Chem. A 2018, 6, 16485.
[32] S. W. Hu, L. W. Yang, Y. Tian, X. L. Wei, J. W. Ding, J. X.
Zhong, P. K. Chu, Appl. Catal. B: Environ. 2015, 163, 611.
[52] Y. F. Zhu, M. Y. Zhu, L. H. Kang, Ind. Eng. Chem. Res. 2015, 54,
2040.
[33] S. Tonda, S. Kumar, S. Kandulab, V. Shanker, J. Mater. Chem.
A 2014, 2, 6772.
[53] H. Wang, C. Wang, Y. Yang, M. Zhao, Y. Wang, Catal. Sci.
Technol. 2017, 7, 405.
[34] Y. S. Jun, E. Z. Lee, X. C. Wang, W. H. Hong, G. D. Stucky, A.
Thomas, Adv. Funct. Mater. 2013, 23, 3661.
[35] L. B. Jiang, X. Z. Yuan, G. M. Zeng, H. Wang, ACS Sustainable
Chem. Eng. 2017, 5, 5831.
How to cite this article: Zhu Z, Wang B, Yao Q,
Zhou Y, Yang H, Liu Y. H3PW12O40/mpg‐C3N4 as
an efficient and reusable catalyst in the alkylation
of o‐xylene and styrene. Appl Organometal Chem.
2019;e5129. https://doi.org/10.1002/aoc.5129
[36] J. Xu, T. J. Brenner, L. Chabanne, D. Neher, M. Antonietti, M.
Shalom, J. Am. Chem. Soc. 2014, 136, 13486.
[37] H. Wang, X. Z. Yuan, Y. Wu, Appl. Catal. B: Environ. 2015, 174,
445.
[38] Y. Li, X. Y. Wua, J. Lia, K. Wang, G. K. Zhang, Appl. Catal. B:
Environ. 2018, 229, 218.