Catalytic dehydration of fructose to 5-hydroxymethylfurfural over a mesoscopically assembled sulfated zirconia nanoparticle catalyst in organic solvent

Article abstract of DOI:10.1039/c4ra09585e

The catalytic dehydration of fructose to 5-hydroxymethylfurfural (HMF) in DMSO was performed over a sequence of mesoscopically assembled sulfated zirconium nanostructures (MASZN) derived from zirconyl chloride with a template as a fastening agent. The materials were characterized by X-ray diffraction, FTIR spectroscopy, NH₃ temperature-programmed desorption, pyridine FTIR spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, and N₂ sorption. The heterogeneous catalyst MASZN with Lewis-Bronsted acid sites had a superior performance in the dehydration of fructose to HMF. With MASZN-3 as catalyst, a HMF yield of 91.9% with a 98.5% fructose conversion was obtained at 110°C for 120 min in DMSO. Finally, the catalyst MASZN-3 was recycled in four consecutive cycles with scarcely any loss of activity. The excellent catalytic properties together with its easy synthesis, low cost, and nontoxic nature make this MASZN a promising catalyst for the development of new and efficient processes for biomass-based chemicals.

Full text of DOI:10.1039/c4ra09585e

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PAPER
Catalytic dehydration of fructose to 5-
hydroxymethylfurfural over a mesoscopically
assembled sulfated zirconia nanoparticle catalyst
in organic solvent†
Cite this: RSC Adv., 2014, 4, 57164
Ningning Wang, Yuan Yao, Wei Li, Yan Yang, Zhanxin Song, Wentao Liu, Haijun Wang,*
Xiao-Feng Xia and Haiyan Gao
The catalytic dehydration of fructose to 5-hydroxymethylfurfural (HMF) in DMSO was performed over a
sequence of mesoscopically assembled sulfated zirconium nanostructures (MASZN) derived from
zirconyl chloride with a template as a fastening agent. The materials were characterized by X-ray
diffraction, FTIR spectroscopy, NH
3
temperature-programmed desorption, pyridine FTIR spectroscopy,
sorption. The
field emission scanning electron microscopy, transmission electron microscopy, and N
2
heterogeneous catalyst MASZN with Lewis–Brønsted acid sites had a superior performance in the
dehydration of fructose to HMF. With MASZN-3 as catalyst, a HMF yield of 91.9% with a 98.5% fructose
Received 1st September 2014
Accepted 28th October 2014
ꢀ
conversion was obtained at 110 C for 120 min in DMSO. Finally, the catalyst MASZN-3 was recycled in
four consecutive cycles with scarcely any loss of activity. The excellent catalytic properties together with
its easy synthesis, low cost, and nontoxic nature make this MASZN a promising catalyst for the
development of new and efficient processes for biomass-based chemicals.
DOI: 10.1039/c4ra09585e
www.rsc.org/advances
HMF to bridge the growing gap between supply and demand of
energy and chemicals.
In recent years, great progress has been made on effective
1
. Introduction
15,16
With the diminishing supply of fossil fuels, much effort has
been devoted to the search for innovative strategies and routes for the synthesis of HMF from C6-based carbohydrates.
resources for the sustainable production of fuels and chemicals High HMF yields were obtained from C6-based carbohydrates
1
–4
17–20
from renewable materials. Biomass with an estimated global in various catalytic systems.
Relative to other C6-based
1
1
production of around 1.0 ꢁ 10 Tons per year has received carbohydrates, the production of HMF from fructose is much
enormous attention due to its considerable potential as a raw easier because of the fact that the fructofuranoic structure is
material for the production of green ne chemicals, fuels and more reactive to dehydration. Therefore, fructose has always
5
–8
fuel additives. Carbohydrates are the major components of been chosen as an ideal model substrate to evaluate the
21
biomass. Thus it is highly desirable to convert carbohydrates to performance of catalytic systems for biomass conversion. The
platform molecules selectively under mild conditions, which traditional approach to the synthesis of HMF from fructose
can subsequently be used for the production of various requires the use of homogeneous mineral acids, organic acids
chemicals.
The use of homogeneous catalysts for
-Hydroxymethylfurfural (HMF), a valuable biomass-derived biomass conversion has been extensively studied and is known
22–25
and ionic liquid.
5
platform compound, is usually derived from degradation of to be highly effective. However, there are several drawbacks to
cellulose, and subsequent dehydration of saccharides, can be this approach, including catalyst separation, reactor corrosion,
9,10
converted to numerous various chemical products and liquid and recyclability. In pursuit of economical, simple, efficient,
1
1–14
fuel or fuel additives,
pharmaceuticals, the petroleum industry, and furanose-based heterogeneous catalysts have been tested under different
potentially useful for ne chemicals, and environmentally friendly HMF production process, various
26
27
polymers. This necessitates the development of sustainable conditions, such as zeolites, functionalized silica, sulfonic
processes for the conversion of biomass and carbohydrates into acid-functionalized metal–organic frameworks (MOF-SO
28
H),
3
2
9
30
heteropolyacids (HPAs), acidic TiO
2
nanoparticles, biomass-
31
derived sulfonated carbonaceous materials, and bifunctional
The Key Laboratory of Food Colloids and Biotechnology, Ministry of Education, School
of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, Jiangsu, SO
32
4
/ZrO
2
.
China. E-mail: wanghj329@outlook.com
Among these heterogeneous catalysts, solid acid ZrO is
most widely used and has inspired great interest in
2
†
Electronic supplementary information (ESI) available. See DOI:
0.1039/c4ra09585e
1
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carbohydrate dehydration systems. Their advantageous cata- chloride and ammonium ions (using AgNO
3
as test reagent).
lytic characteristics stem from not only the strength of the acid, Then the precipitate was transferred to an aqueous acidic
33
but also the type of acidity (Brønsted and Lewis); therefore, (HNO ) solution and was sonicated until a transparent nano-
3
enabling enhanced activity and selectivity. As a result, much particles sol was generated. The nal pH of the solution was <1,
attempt was previously devoted to synthesizing high active and the generated particles remained highly dispersible
sulfated ZrO
bifunctional sulfated zirconia as catalyst for the conversion of
fructose and glucose to HMF in 8.3 and 6.8% yields, respec- using premade ZrO
2
catalyst. Karen Wilson and co-workers used without sedimentation for a prolonged period.
2.2.2 Preparation of MAZN. MAZN were constructed by
nanoparticles as building blocks. In the
solid catalysts are synthetic procedure, premade ZrO nanoparticles (1 mmol)
2
32
tively. Although the bifunctional SO
4
/ZrO
2
2
promising in terms of recyclability and easy separation, they were added to SDS solution (0.320 g, 1.1 mmol) in water (80 mL)
suffer from poor yield and selectivity. More recently, Yadong Yin at vigorous stirring at ambient temperature. The slurry was
reported the synthesis of sulfated ZrO hollow nanostructures stirred for 2 h at ambient temperature, then stirred further in an
2
with controllable physical and chemical properties and their oil bath at 353 K for 3 h and slowly cooled down to RT. The self-
ꢀ
catalytic application in the dehydration of fructose to HMF assembled nanoparticles were ltered and dried at 80 C over-
3
4
(
64%).
It has been demonstrated that catalytic systems that contain obtain template-free MAZN. This sample was designated as
both Lewis and Brønsted acidity are more benecial for HMF MAZN-1.
night, and then calcined at 873 K for 5 h in the presence of air to
35
production than Lewis or Brønsted acidic catalysts alone.
The other three materials were prepared by varying the molar
Herein, we report the synthesis of mesoscopically assembled ratio of the precursors, such as XZrO /YSDS/ZH O. In all these
2
2
sulfated zirconia nanoparticles (MASZN) with special physical cases X ¼ 1, and only Y and Z were varied. The four sets of
and chemical properties and their catalytic application in the variation were Y ¼ 0.56, Z ¼ 2224; Y ¼ 0.28, Z ¼ 1112; and Y ¼
dehydration of fructose to 5-hydroxymethylfurfural (HMF). A 0.14, Z ¼ 556. The sample abbreviations were MAZN-2, MAZN-3,
high surface area facilitates the integration of the sulfate and MAZN-4, respectively.
functionality and an open framework structure provides easy
2.2.3 Preparation of MASZN. Mesoporous sulfated zirconia
access to the active sites in the chemical reactions. The exible was synthesized by treating 1 g of the above prepared calcined
synthetic procedure allows easy structural optimization and mesoporous zirconia sample twice with 15 mL of 1 N sulfuric
produces MASZN with higher catalytic performance than solid acid followed by calcination in air at 833 K for 2 h.
particles. The mesoporous nano-assemblies provided efficient
catalytic reusability in the fructose reaction with negligible loss
of activity.
2.3. Characterisation techniques
X-ray diffraction (XRD) analyses of the samples were performed
by using a D8 Advance Bruker AXS diffractometer operated at 18
kW and calibrated with a standard silicon sample. XRD patterns
were obtained using a X-ray diffractometer with Ni-ltered Cu-
Ka (l ¼ 0.15406 nm) radiation and a beam voltage of 40 kV and
2
. Experimental
2
.1. Chemicals
Anionic structure-directing agent CH
zirconyl chloride (ZrOCl $8H O), ammonia (NH
solution), and nitric acid (HNO , 60%), fructose (BR) were
obtained from the Sinopharm Chemical Reagent Co. Ltd.
Shanghai, China). DMSO, 1-allyl-3-methylimidazolium chlo-
3
(CH
2
)
11OSO
3
Na (SDS) and
2
2
3
, 28%, aqueous
40 mA beam current.
3
Transmission electron micrographs (TEM) of catalysts were
obtained by using a JEOL JEM model 2100 microscope operated
at 200 kV. TEM images were obtained by using a CCD camera.
Samples were dispersed in ethanol and a drop of the dispersion
was placed on a carbon coated copper grid (300 mesh) and
allowed to dry.
Field emission scanning electron microscopy (FESEM)
micrographs were taken on a HITACHI S-4800 emission scan-
ning microscope at an accelerating voltage of 3 kV with a beam
(
ride ([AMIM]Cl) and other chemicals (AR) are commercially
available and used without further purication unless other-
wise stated. Deionized water was produced by using a laboratory
water-purication system (RO DI Digital plus).
2.2. Catalyst preparation
The synthesis involved two steps: (1) the synthesis of ZrO2 current of 1 mA.
nanoparticles and (2) the fabrication of a mesoscopic nano-
The Brunauer–Emmett–Teller (BET) surface areas were
determined by adsorption/desorption measurements
(Micromeritics ASAP 2020) done at 77 K. Prior to the gas
nanoparticles were prepared by using adsorption/desorption measurements, all samples were
assembly architecture.
N
2
2
.2.1 Preparation of a sol of uniform monodisperse ZrO
nanoparticles. ZrO
suitable modication of previous work published elsewhere.
2
2
36
degassed at 473 K for 4 h to remove water and other physically
First of all, zirconium hydride Zr(OH) was synthesized by dis- adsorbed species. Surface areas were calculated using the Bru-
4
solving 3.22 g of zirconyl chloride (ZrOCl $8H O, 10 mmol) in nauer–Emmett–Teller (BET) method over the range P/P ¼ 0.05–
2
2
0
100 mL distilled water, followed by precipitation with ammo- 0.30, where a linear relationship was maintained. Pore size
nium hydroxide solution controlled at a pH of 10. The precipi- distributions were calculated using the Barrett–Joyner–Halenda
tate was repeatedly washed with distilled water till free of (BJH) model.
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NH
experiments were carried out on a chemisorption apparatus
Micromeritics; AutoChem II 2920) equipped with a TCD
detector. Prior to the adsorption of NH , ca. 100 mg sample was
3
3
temperature-programmed desorption (NH -TPD)
(
3

rst preheated at 383 K under owing He for 0.5 h to remove
undesirable physisorbed species, followed by heating under He
environment at 873 K for 1 h, then cooled to 393 K. Subse-
quently, the sample was exposed to owing ammonia gas
3
mixture (5% NH in He) for 1 h, then purged by He gas for 40
min to remove excessive physisorbed ammonia. All NH -TPD
3
proles were carried out by ramping the temperature from 373
ꢂ1
to 873 K at a rate of 10 K min
.
The FTIR spectra of these samples were obtained by using an
IR FTLA2000-104 spectrophotometer from ABB-Bomem Inc.
FTIR spectra of adsorbed pyridine were also recorded on this
spectrometer. Prior to the measurements, the catalysts were
pressed in self-supporting disks and activated in the IR cell
ꢀ
attached to a vacuum line at 300 C for 4 h. Adsorption of
Fig. 1 (a and b) FE-SEM images of calcined samples MASZN-3. (c and
ꢀ
pyridine (Py) was performed at 150 C for 30 min. The excess of d) TEM images of calcined samples MASZN-3 seen through the
Py was further evacuated at 150 C for 1 h in vacuum.
ꢀ
direction perpendicular to the pore axis.
2
.4. Catalytic reactions
from the gure, this mesoporous zirconia material is composed
of similar spherical particles, which shows a regular self-
assembled arrangement. Since we sonicated the sample before
the TEM measurement, these zirconia nanoparticles lost their
regular self-assembled arrangement as seen in the TEM image.
The TEM images conrmed the nano-size nature of synthesized
The batch catalytic experiments were conducted in a 50 mL
stainless steel autoclave with glass liner tube. Fructose (1 mmol)
as substrate and 3 mL of DMSO as solvent were rstly added in
the reactor and then 10 mg of catalyst was added into the
ꢀ
mixture, the mixture was vigorously stirred at 110 C for the
desired duration of time. Under these conditions the mass
transfer effect was eliminated. When the reaction was
completed, the reactor was cooled to room temperature, the
catalyst was separated by centrifugation and the post-reaction
sample was diluted with deionized water, and analyzed by
high-performance liquid chromatography (HPLC).
The liquid samples were analyzed with HPLC using a Agilent
Alliance System instrument (1100 series) equipped with a
refractive index detector and a UV detector, and a Shodex
SUGAR SP0810 (300 ꢁ 8.0) columns for analysis. Deionized
water was used as the eluent phase, with a ow rate of 0.7 mL
ZrO particles (Fig. 1(c) and (d)). In the image, low electron density
2
spots (pores) are seen throughout the specimen, and the particles
of size approximately 7.0–8.0 nm are arranged in a regular
mesoscopic order. Interparticle pores as seen in this image (low
electron density spots) vary from 4.0 to 6.0 nm in the length scale.
The TEM image shows that the powder sample consists of
aggregated nanoparticles and estimated pore size were consistent
2
with N adsorption/desorption measurements, as shown in
Table 1. Otherwise, the nano singular structure (in Fig. 1(d)) may
37
be result of the oriented aggregation of nanoparticles.
.1.2 Powder X-ray Diffraction (XRD). The powder X-ray
3
ꢂ1
ꢀ
min and 70 C column temperature. Product yields were
calculated from response factors determined from multi-point
calibration curves. Conversion of the reactant, yield and selec-
tivity of the products were calculated as follows:
diffraction patterns for calcined self-assembled zirconia and
sulfated self-assembled zirconia materials are shown in Fig. 2
and 3, respectively. The XRD results for both types of materials
exhibited a mixture of well-resolved characteristic of monoclinic
38–41
2
and tetragonal phases of individual ZrO nanoparticles.
Conversion of reactant (%) ¼ [C
ꢂ Creactant]/Creactant,t¼0
reactant,t¼0
100%
Calcined MAZN possessed a tetragonal phase, which is its major
characteristic (Fig. 2). Aer sulfating integration, the mono-
clinic phase became more prominent, as observed in the Fig. 3.
Thus, integrated sulfate ions had a strong inuence on phase
ꢁ
Yield of product i (%) ¼ C
Selectivity of product i (%) ¼ C
i
/Creactant,t¼0 ꢁ 100%
/[Creactant,t¼0 ꢂ Creactant] ꢁ 100% modication. Sulfate ions converted the metastable tetragonal
i
phase to its more thermodynamically stable monoclinic
32
here, C is the molar concentration of species i.
i
phase. In the research, the particle sizes of catalysts were
calculated by using the Scherrer equation. The estimated
particle sizes varied from 7.0 to 8.0 nm (see the ESI†). These
results were in agreement with the TEM image analysis results
3
3
. Results and discussion
.1. Catalyst characterisation
(
Fig. 1(c) and (d)). Otherwise, more monoclinic ZrO generated
2
3
.1.1 TEM and FE-SEM analysis. FE-SEM image of the via calcination, which had been reported to exhibit predomi-
42,43
mesoporous zirconia sample is shown in Fig. 1(a) and (b). As seen nantly Lewis acidity.
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Table 1 Physico-chemical properties of mesoscopic-assembly zirconia and sulfated zirconia nanoparticles
2
ꢂ1
3
ꢂ1
a
ꢂ1
Entry
Sample type
Surface area [m g
]
Pore volume [cm g
]
Average pore size [nm]
Acid concentration [mmol g
]
1
2
3
4
5
6
7
8
MAZN-1
MAZN-2
MAZN-3
MAZN-4
MASZN-1
MASZN-2
MASZN-3
MASZN-4
124.2
113.7
102.8
66.5
92.7
86.3
0.283
0.245
0.214
0.101
0.175
0.134
0.203
0.127
5.91
4.39
4.36
4.10
5.73
4.57
4.19
4.82
0.032
0.027
0.018
0.022
0.124
0.137
0.165
0.110
95.4
53.8
a
3
Acid concentration values were determined through NH -TPD.
and pore volume for the calcined and sulfated mesoporous
MAZN are shown in Table 1 (entries 1–4 for the calcined MAZN
and entries 5–8 for the MASZN). The BET surface area of the
calcined MAZN-1, MAZN-2, MAZN-3, and MAZN-4 were 124.2,
2
ꢂ1
1
13.7, 102.8, and 66.5 m g , respectively. The surface area of
the MASZN-1, MASZN-2, MASZN-3 and MASZN-4 were 92.7,
2
ꢂ1
8
6.3, 95.4 and 53.8 m g , respectively. These average pore
sizes in Table 1 are consistent with the above-mentioned TEM
experimental data. The pore volumes of the corresponding
calcined materials decreased aer the incorporation of the
sulfate group, as shown in Table 1 (entries 5–8). Thus, the
surface areas as well as the pore volumes of the calcined
matrices decreased upon sulfate integration, which can be
attributed to the dispersion of sulfate groups on the surface of
the porous framework. Moreover, a kind of pore blocking can
44
also occur. Material MASZN-3 acid site concentration of 0.165
ꢂ1
Fig. 2 Wide-angle PXRD patterns of mesoscopic-assembly zirconia mmol g was estimated using the NH -TPD. The higher acid
3
samples: (a) MAZN-1, (b) MAZN-2, (c) MAZN-3; (d) MAZN-4 (*)
site concentration of MASZN-3 could be attributed to a high
ꢀ
monoclinic phase, ( ) tetragonal phase.
external surface area because of the tiny nanoparticle
morphology, large pore size, and high pore volume that expose
a larger number of acid sites at the surface of the material,
comparing with other MASZN materials.
3.1.4 FTIR spectroscopy. The IR spectra of the calcined and
sulfated MASZN are shown in Fig. 4. The absence of bands at
ꢂ1
approximately n ¼ 2854 and approximately 2925 cm in these
samples, which are ascribed to the symmetric and asymmetric
vibrations of the C–H groups, indicated the complete removal of
SDS molecules aer calcination. A broad band in the range of
ꢂ1
ꢂ1
3
000–3600 cm and 1620 cm can be assigned to asymmetric
OH stretching vibrations of the adsorbed water molecule,
45
respectively.
ꢂ1
The spectral feature ranging from n ¼ 1400 to 900 cm was
very important in characterizing the presence of sulfate moie-
ties in MASZN, and all MASZN materials exhibited almost
similar spectral features. Vibrational bands are observed
attributable to n
at 1380 cm , consistent with bidentate or tridentate SO
s
(S–O) at 1010, nas (S–O) at 1128, and nas (S]O)
Fig. 3 Wide-angle PXRD patterns of sulfated samples: (a) MASZN-1,
ꢂ1
2ꢂ 46,47
ꢀ
4
.
(
b) MASZN-2, (c) MASZN-3; (d) MASZN-4 (*) monoclinic phase, ( )
This spectral investigation described the integration of sulfate
moieties into the ZrO nanoparticles. The partial ionic nature of
the S–O bonds was responsible for the strong Brønsted acidity
tetragonal phase.
2
48
3
.1.3 N sorption studies. N sorption studies are impor- of the sulfate-modied ZrO
2
nanoparticles. The non-surface
tant to determine the porous nature of the materials. In the MAZN samples were also investigated by FTIR spectroscopy
current research, the BET surface area, average pore diameter (see ESI, Fig. S4†). When the mesoporous ZrO samples were
2
2
2
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sites. The results indicate that catalysts MASZN have Lewis–
Brønsted acid sites simultaneously. NH -TPD experiments were
3
conducted to determine the relative strengths of acid sites of
MASZN-3 (see ESI, Fig. S1†). In this prole, a major desorption
ꢀ
occurred between 250 to 500 C, and one broad peak centered at
ꢀ
3
55 C was observed. Compared to the desorption peak
observed for sulfated zirconia supported over mesoporous silica
ꢀ
50
at 257 C, our self-assembled mesoporous sulfated zirconia
ꢀ
sample showed a peak at much higher temperature (355 C).
This peak (TCD signal maxima) can be assigned because of the
formation of strongly bound (chemisorbed) ammonia on highly
acidic sulfated zirconia surface.
Fig. 4 FTIR spectra of the sulfated samples: (a) MASZN-1, (b) MASZN-
3
.2. Catalytic study
2
, (c) MASZN-3 and (d) MASZN-4. In the inset, the FTIR spectra of
ꢂ1
3.2.1 Dehydration of fructose over MAZN and MASZN. The
MASZN-3 ranging from n ¼ 1800 to 600 cm are shown.
catalytic dehydration of fructose to HMF in DMSO using MAZN
and MASZN as catalysts at 110 C was investigated. Fig. 6 shows
ꢀ
ꢀ
the reaction results of the MAZN and MASZN samples varying
the molar ratio of XZrO /YSDS/ZH O, respectively. Obviously,
2 2
directly calcined at 600 C without introducing any sulfate ions,
it shows only broad absorption bands in the range of 500–650
ꢂ1
catalytic performance of the catalysts was noticeably affected by
the molar ratio of precursors. The MAZN-1 and MASZN-3 have
the superior performance in conversion of fructose into HMF
among the series of MAZN materials. When the reaction was
and 990–1250 cm
without any clear peaks related to the
sulfate groups. The high surface area of the mesoporous MAZN
facilitated the integration of the sulfate functionality to a suit-
able extent within its framework; hence, acid-catalyzed reac-
tions were accelerated.
ꢀ
carried out at 110 C, the results showed that the catalyst
MASZN-3 gave the highest yield of HMF, which is closely related
with its structure and surface acidity. The sample MASZN-3 is
mesoporous, and it has the higher BET surface area and the
highest concentration of acid sites (entry 7, Table 1). The
Fig. 6(c) also indicates that HMF yield monotonously increases
with the reaction time, attaining the maximum value of 91.9%
aer 120 min. Nevertheless, higher reaction times barely
improve the formation of HMF, possibly due to the preferential
formation of soluble polymers and humins, as well as the
deposition of residues formed from intermediates condensa-
tion on the active sites.
3
.1.5 Acidity characterization by pyridine-IR spectroscopy
and NH -TPD. In order to gain more information about acid
3
sites on the surface of these sulfate catalysts, the infrared
spectra of pyridine adsorbed on the MASZN samples were
recorded and the results were shown in Fig. 5. In the pyridine-
adsorption FTIR spectrum, four peaks were observed in the
region between 1400–1600 cm due to C–C stretching vibra-
tions of pyridine. The peak at 1450 cm was assigned to pyri-
dine adsorbed on Lewis acid sites; the peak at 1540 cm and
640 cm are characteristic of pyridine adsorbed on Brønsted
acid sites, whereas the band at 1495–1500 cm is normally
attributed to a combination band associated with both B- and L-
ꢂ1
ꢂ1
ꢂ1
ꢂ1
1
49
ꢂ1
3.2.2 Effect of reaction temperature and MASZN-3 loading
on dehydration. Temperature and dosage of catalyst as the most
critical parameters were initially investigated in the systematic
evaluation process. To conrm the best conditions, the degra-
dation of fructose in DMSO media was studied. Firstly, the
inuence of the temperature on the catalytic reaction has been
evaluated by using the MASZN-3 catalyst. The catalytic results
reect that HMF yield rises with increase of temperature and
ꢀ
time at rst, achieving a value close to 92% at 110 C (Fig. 7(a)).
ꢀ
Then the drastic decreasing in HMF yield from 110 to 130 C
can be explained by the rapid formation of humins on the
catalyst surface, thus covering some acid sites and limiting the
transformation of fructose; in fact, the catalyst became brown
ꢀ
aer 20 min of reaction at the highest temperature (130 C). As
is shown in Fig. 7(a), both too high temperature and too long
time were not conducive to the stability of HMF due to the side
reaction. The highest yield of HMF was 91.9% obtained at 110
ꢀ
ꢀ
C for 120 min. From these date, 110 C was considered as
optimal reaction temperature to study other parameters of the
catalytic process.
Fig. 5 FTIR spectra of pyridine adsorbed over MASZN: (a) MASZN-1, (b)
MASZN-2, (c) MASZN-3 and (d) MASZN-4.
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Fig. 6 Fructose transformation into HMF using mesoscopic assembly zirconia and sulfated zirconia nanoparticles as catalysts. Reaction
ꢀ
conditions: initial reactant (1 mmol), catalysts (10 mg), solvents system DMSO (3 mL), 110 C.
Fig. 7 (a) Effect of the reaction temperature on the yield of HMF from the dehydration of fructose catalyzed by MASZN-3. Conditions: fructose (1
mmol), DMSO (3 mL), MASZN-3 weight (10 mg); (b) results of the experiment into the dosage of MASZN-3 on the direct transformation of
ꢀ
fructose into HMF in DMSO. Conditions: fructose (1 mmol), DMSO (3 mL), T ¼ 110 C, reaction time: all reactions were performed at the same
catalyst space time; blue bar: HMF yield, red bar: fructose conversion.
ꢀ
Next, the inuence of the MASZN-3 loading at 110 C for of MASZN-3 increases, thus meaning that the increased
1
20 min was evaluated. The variation of the amount of catalyst amounts of catalyst has not facilitated the transformation of
5–15 mg) shows that the fructose conversion barely improves fructose into HMF but into undesired products such as soluble
with increasing MASZN-3 loading, possibly as a consequence of polymers and humins.
(
the higher activity of MASZN-3 in conversion of fructose in
3.2.3 HMF synthesis from various substrates. The prom-
DMSO (Fig. 7(b)). When the dosage of MASZN-3 was 10 mg, the ising catalytic activity of the mesoporous MASZN for fructose
reaction time was setted as 2 h. The other reactions would be dehydration has prompted us to test the effectiveness of this
conducted at the same catalyst space time (e.g. for double the catalyst for HMF synthesis from glucose and other carbohydrate
amount of catalyst taking half the reaction time). Initially, the such as sucrose, inulin in [AMIM]Cl.
HMF yield augments with the increase of catalyst weight.
The reaction conditions of glucose, sucrose, inulin dehy-
However, when the loading of MASZN-3 is above 10 mg, the dration reactions and corresponding HMF yields, conversions
HMF yield begins to monotonically decrease, while the dosage and HMF selectivity were summarized in Table 2. Under
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Table 2 Conversion, yield and product selectivity following sugars dehydration over mesoscopic assembly zirconia and sulfated zirconia
a
nanoparticles
ꢀ
b
Entry
Substrate
Catalysis
t (min)
T ( C)
Conversion (%)
HMF yield (%)
HMF selectivity (%)
1
2
3
4
5
6
7
8
9
Fructose
Fructose
Fructose
Glucose
Glucose
Glucose
Glucose
Sucrose
Inulin
MASZN-3
MASZN-3
MASZN-3
MASZN-1
MASZN-2
MASZN-3
MASZN-4
MASZN-3
MASZN-3
30
120
180
60
60
60
60
180
120
110
110
110
120
120
120
120
120
110
97.1
98.5
99.6
42.6
67.8
45.2
49.5
98.8
95.3
72.8
91.9
73.7
5.6
15.4
7.4
9.2
43.7
54.8
75.0
92.9
74.0
13.1
22.7
16.3
18.6
44.2
57.5
a
b
Conditions: initial reactant (1 mmol), each catalyst is 10 mg; solvent of fructose is DMSO (3 mL); solvent of other sugar is [AMIM]Cl (3 mL). HMF
yield was equal to mol (HMF)/mol (total monomer).
Fig. 8 (a) HMF yields in various runs, upon catalyst recycling for transformation of fructose with DMSO by using sulfated MASZN-3 catalyst. (b)
Recyclability study of the MASZN-3 catalyst for the conversion of fructose. Reaction conditions: fructose (1 mmol), catalysts (10 mg), solvents
ꢀ
system DMSO (3 mL), 110 C.
comparable reaction conditions, MASZN-3 catalyzed reaction in separation of the solid catalyst, which was then reused with
DMSO from fructose produced 72.8%, 91.9%, and 73.7% HMF fresh reagents in the same reaction conditions.
for various reaction time, respectively (entries 1–3, Table 2).
No loss of catalytic activity was observed. Aer each catalytic
These results clearly indicates that mesoporous MASZN-3 is an run the catalyst was recovered by ltration, washed thoroughly
effective catalyst for HMF synthesis from fructose. Several with methanol, and drying in an oven at 373 K overnight. The
experiments were designed for screening the catalytic effec- catalyst was subsequently activated at 473 K for 4 h under air
tiveness of various MASZN catalysts for HMF production from ow, and was then utilized for the following reaction. In all four
glucose in [AMIM]Cl, and MASZN-2 was regarded as the opti- consecutive catalytic runs, the HMF yield remained constant at
mized catalyst, leading to 67.8% of glucose conversion, 15.4% of about 90–92% for 2 h, as shown in Fig. 8(a). Otherwise, the loss
HMF yield and 22.7% of HMF selectivity; this activity could be of activity of the catalyst, in terms of conversion of fructose,
assigned to the participation of the Lewis and Brønsted acid aer four cycles was negligible (Fig. 8(b)). The loss of activity
sites. When MASZN-3 acted as catalyst, 43.7% and 54.8% HMF was mainly caused by the formation of carbon deposition on the
yields were achieved from sucrose and inulin dehydration in catalyst surface. This clearly demonstrates that the catalytic
[AMIM]Cl, respectively. Under identical reaction conditions, performance of the MASZN-3 is preserved in the consecutive
glucose dehydration reaction produced less HMF than that of runs, and that the catalyst system is highly suitable for reuse.
sucrose dehydration reaction. The probable reason is that Thus, the sulfated mesoporous MASZN described herein have a
sucrose is a disaccharide consisting of glucose and fructose, great potential to be used as a stable and highly active recyclable
and only the ketose product (fructose) could efficiently convert solid acid catalyst in biomass dehydration.
into HMF.
3
.2.4 Catalyst recycles. The stability of the MASZN catalysts
4. Conclusions
as well as the heterogeneous nature of the catalysis were tested
by recycling the catalyst. The hot ltration of a MASZN-3 catalyst In summary, we have presented a synthesis route for meso-
solution in optimized reaction conditions allowed the scopically assembled sulfated zirconia nanoparticles with an
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average diameter of ca. 5.0 nm and high crystalline pore walls of 12 S. Zhong, R. Daniel, H. Xu, J. Zhang, D. Turner,
mesoscopic order through evaporation-induced self-assembly
method using SDS as the template. The presence of sulfonic
M. L. Wyszynski and P. Richards, Energy Fuels, 2010, 24,
2891.
acid groups and Lewis acidic ZrO2 in the material has been 13 J. P. Lange, E. van der Heide, J. van Buijtenen and R. Price,
conrmed by FTIR and pyridine-desorption FTIR spectroscopy, ChemSusChem, 2012, 5, 150.
NH temperature-programmed desorption, XRD, FESEM, TEM, 14 M. J. Climent, A. Corma and S. Iborra, Green Chem., 2014, 16,
and N
3
2
adsorption/desorption. The total surface acid density of
MASZN-3 was 0.165 mmol g . The material shows a good 15 J. B. Binder and R. T. Raines, J. Am. Chem. Soc., 2009, 131,
516.
ꢂ1
catalytic activity for the dehydration of biomass-derived
glucose, sucrose, and inulin to 5-hydroxymethylfurfural 16 T. Wang, M. W. Nolte and B. H. Shanks, Green Chem., 2014,
HMF), which enables maximum yields of 21.5, 43.7, and 54.8%, 16, 548.
respectively, in a [AMIM]Cl solvent system. MASZN-3 catalyst 17 H. Yan, Y. Yang, D. Tong, X. Xiang and C. Hu, Catal.
1979.
(
has demonstrated to be the most active, exhibiting high fruc-
tose conversion (98.5%) and HMF yield (91.9%) at 110 C and 18 Q. Zhao, L. Wang, S. Zhao, X. Wang and S. Wang, Fuel, 2011,
Commun., 2009, 10, 1558.
ꢀ
aer 120 min of reaction time in DMSO. The recyclability
experiments show that the catalyst retained full activity aer 19 H. Zhao, J. E. Holladay, H. Brown and Z. C. Zhang, Science,
four consecutive cycles, and the loss in activity, in terms of HMF 2007, 316, 1597.
yield, was only 2%. These newly discovered mesoscopically 20 M. Dashtban, A. Gilbert and P. Fatehi, RSC Adv., 2014, 4,
assembled sulfated zirconia nanoparticles for biomass conver- 2037.
sion open up a new avenue of cost effective biomass renery 21 R. Liu, J. Chen, X. Huang, L. Chen, L. Ma and X. Li, Green
90, 2289.
processes toward the production of affordable biochemicals
Chem., 2013, 15, 2895.
and biofuels.
22 Y.-N. Li, J.-Q. Wang, L.-N. He, Z.-Z. Yang, A.-H. Liu, B. Yu and
C.-R. Luan, Green Chem., 2012, 14, 2752.
2
3 Z. Kelemen, O. Holl ´o czki, J. Nagyc and L. Nyul ´a szi, Org.
Biomol. Chem., 2011, 9, 5362.
Acknowledgements
2
2
4 J. O. Metzger, Angew. Chem., Int. Ed., 2006, 45, 696.
5 T. Buntara, S. Noel, P. H. Phua, I. Melian-Cabrera, J. G. de
Vries and H. J. Heeres, Angew. Chem., Int. Ed., 2011, 50, 7083.
6 J. Gonz ´a lez-Rivera, I. R. Galindo-Esquivel, M. Onor,
E. Bramanti, I. Longo and C. Ferrari, Green Chem., 2014,
The authors are grateful to the National Natural Science Foun-
dation of China (21206057), the Natural Science Foundation of
Jiangsu Province, China (BK2012118) and (BK2012547), and
MOE & SAFEA for the 111 Project (B13025) for nancial support.
2
2
16, 1417.
7 A. J. Crisci, M. H. Tucker, M.-Y. Lee, S. G. Jang, J. A. Dumesic
Reference
and S. L. Scott, ACS Catal., 2011, 1, 719.
1
Y.-S. Jang, B. Kim, J. H. Shin, Y. J. Choi, S. Choi, C. W. Song, 28 J. Chen, K. Li, L. Chen, R. Liu, X. Huang and D. Ye, Green
J. Lee, H. G. Park and S. Y. Lee, Biotechnol. Bioeng., 2012, 109,
Chem., 2014, 16, 2490.
437.
2
29 S. Zhao, M. Cheng, J. Li, J. Tian and X. Wang, Chem.
Commun., 2011, 47, 2176.
2
3
4
A. I. Rushdi, K. F. Al-Mutlaq, S. K. Sasmal and
B. R. T. Simoneit, Fuel, 2013, 103, 970.
D. M. Alonso, J. Q. Bond and J. A. Dumesic, Green Chem.,
30 C.-H. Kuo, A. S. Poyraz, L. Jin, Y. Meng, L. Pahalagedara,
S.-Y. Chen, D. A. Kriz, C. Guild, A. Gudz and S. L. Suib,
Green Chem., 2014, 16, 785.
2010, 12, 1493.
P. N. Vennestrom, C. M. Osmundsen, C. H. Christensen and 31 X. Qi, H. Guo, L. Li and R. L. Smith Jr, ChemSusChem, 2012,
E. Taarning, Angew. Chem., Int. Ed., 2011, 50, 10502.
5, 2215.
A. Corma, S. Iborra and A. Velty, Chem. Rev., 2007, 107, 2411. 32 A. Osatiashtiani, A. F. Lee, D. R. Brown, J. A. Melero,
P. Daorattanachai, P. Khemthong, N. Viriya-empikul,
G. Morales and K. Wilson, Catal. Sci. Technol., 2014, 4, 333.
N. Laosiripojana and K. Faungnawakij, Carbohydr. Res., 33 T. Wang, Y. J. Pag ´a n-Torres, E. J. Combs, J. A. Dumesic and
012, 363, 58. B. H. Shanks, Top. Catal., 2012, 55, 657.
S. Singh, M. A. Nahil, X. Sun, C. Wu, J. Chen, B. Shen and 34 J. B. Joo, A. Vu, Q. Zhang, M. Dahl, M. Gu, F. Zaera and
P. T. Williams, Fuel, 2013, 105, 585. Y. Yin, ChemSusChem, 2013, 6, 2001.
A. J. Ragauskas, C. K. Williams, B. H. Davison, G. Britovsek, 35 E. Nikolla, Y. Rom ´a n-Leshkov, M. Moliner and M. E. Davis,
J. Cairney, C. A. Eckert, W. J. Frederick Jr, J. P. Hallett,
ACS Catal., 2011, 1, 408.
D. J. Leak, C. L. Liotta, J. R. Mielenz, R. Murphy, 36 A. S. Deshpande, N. Pinna, P. Beato, M. Antonietti and
5
6
2
7
8
R. Templer and T. Tschaplinski, Science, 2006, 311, 484.
J. Lewkowski, ARKIVOC, 2001, 17.
M. Niederberger, Chem. Mater., 2004, 16, 2599.
37 H. Z. Cui, J. Q. Sun and Y. Wang, Mater. Rev., 2009, 23, 138.
9
1
0 Y. Rom ´a n-Leshkov, J. N. Chheda and J. A. Dumesic, Science, 38 H. Chen, J. Shi, Z. Liu, J. Gao, M. Ruan and D. Yan, Adv.
006, 312, 1933. Mater., 2005, 17, 2010.
1 G. Tian, R. Daniel, H. Li, H. Xu, S. Shuai and P. Richards, 39 B. M. Reddy, P. M. Sreekanth and P. Lakshmanan, J. Mol.
Energy Fuels, 2010, 24, 3898. Catal. A: Chem., 2005, 237, 93.
2
1
This journal is © The Royal Society of Chemistry 2014
RSC Adv., 2014, 4, 57164–57172 | 57171

View Article Online
RSC Advances
Paper
4
4
4
4
4
0 J. R. Sohn, T.-D. Kwon and S.-B. Kim, Bull. Korean Chem. Soc., 45 S. K. Das, M. K. Bhunia, M. Motin Seikh, S. Dutta and
001, 22, 1309. A. Bhaumik, Dalton Trans., 2011, 40, 2932.
1 Y.-S. Hsu, Y.-L. Wang and A.-N. Ko, J. Chin. Chem. Soc., 2009, 46 S. J. HUG, J. Colloid Interface Sci., 1997, 188, 415.
6, 314. 47 F. Haase and J. Sauer, J. Am. Chem. Soc., 1998, 120, 13503.
2 C. M. Vera Bolis, M. Volante, L. Orio and B. Fubini, Langmuir, 48 T. Yamaguchi, T. Jin and K. Tanabe, J. Phys. Chem., 1986, 90,
990, 6, 695. 3148.
3 V. Bolis, G. Cerrato, G. Magnacca and C. Morterra, 49 F. Babou, G. coudurier and J. C. Vedrine, J. Catal., 1995, 152,
Thermochim. Acta, 1998, 312, 63. 341.
4 M. K. Bhunia, S. K. Das, P. Pachfule, R. Banerjee and 50 X.-R. Chen, Y.-H. Ju and C.-Y. Mou, J. Phys. Chem. C, 2007,
A. Bhaumik, Dalton Trans., 2012, 41, 1304. 111, 18731.
2
5
1
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This journal is © The Royal Society of Chemistry 2014