A heteropoly acid ionic crystal containing Cr as an active catalyst for dehydration of monosaccharides to produce 5-HMF in water

Article abstract of DOI:10.1039/c4cy01555j

Cs₂[Cr₃O(OOCC₂H₅)₆(H₂O)₃]₂[α-SiW₁₂O₄₀], a chromium-based heteropoly acid (HPA) ionic crystal, was demonstrated to be an active heterogeneous catalyst for production of 5-hydroxymethylfurfural (HMF) from fructose or glucose. The dependencies of catalytic activity on reaction parameters such as solvent, temperature and reaction time were investigated and the reaction conditions were optimized. Based on fructose, the yield of HMF reaches 86% and 56% when using DMSO and water as solvents, respectively. Starting from glucose, a yield of HMF up to 48% can be achieved for both aqueous and DMSO media. The catalyst was successfully recycled 5 times. This journal is

Full text of DOI:10.1039/c4cy01555j

Catalysis
Science &
Technology
View Article Online
View Journal
PAPER
A heteropoly acid ionic crystal containing Cr as an
active catalyst for dehydration of monosaccharides
to produce 5-HMF in water†
Cite this: DOI: 10.1039/c4cy01555j
ab
b
a
a
a
Xiaohu Yi, Irina Delidovich, Zhong Sun, Shengtian Wang, Xiaohong Wang* and
Regina Palkovits*b
2 3 2 5 6 2 3 2
Cs ijCr OIJOOCC H ) IJH O) ] ijα-SiW12O40], a chromium-based heteropoly acid (HPA) ionic crystal, was
demonstrated to be an active heterogeneous catalyst for production of 5-hydroxymethylfurfural (HMF)
from fructose or glucose. The dependencies of catalytic activity on reaction parameters such as solvent,
temperature and reaction time were investigated and the reaction conditions were optimized. Based on
fructose, the yield of HMF reaches 86% and 56% when using DMSO and water as solvents, respectively.
Starting from glucose, a yield of HMF up to 48% can be achieved for both aqueous and DMSO media. The
catalyst was successfully recycled 5 times.
Received 27th November 2014,
Accepted 16th February 2015
DOI: 10.1039/c4cy01555j
www.rsc.org/catalysis
However, the yields of HMF in aqueous medium are
restricted to ca. 35% owing to the acid-catalyzed rehydration
Introduction
4
Gradual exhaustion of available fossil feedstocks prompts the
search for renewable raw materials. Renewable and abun-
of HMF leading to levulinic acid and formic acid. Only appli-
1
2
cation of rather complex procedures, i.e. reactive extraction
1
1,12
dant cellulosic biomass is a promising alternative for substi-
or adsorption
of HMF, helps to improve the yield of this
2
tution of fossil resources in the chemical industry. C
6
mono-
product. The highest yields of HMF are obtained when using
fructose as substrate, whereas hydrolysis of cellulose gives
rise to glucose. Although glucose is an economically more
suitable substrate for production of HMF, the acidic dehydra-
tion of glucose is very unselective and yields only ca. 20% of
saccharides are readily available via hydrolysis of cellulose
3
and hemicelluloses. Dehydration of these monosaccharides
results in formation of HMF which is a promising platform
substance for production of fuels and chemicals.
4
Dehydration of saccharides takes place in the presence of
HMF. In general, a successful conversion of glucose into
4
catalysts with Brønsted acidic functionalities. The yield of
HMF requires first the isomerization into fructose with sub-
sequent dehydration of the latter in the presence of a tandem
catalytic system for these subsequent reactions, e.g. a combi-
nation of chromium salts (Lewis acid for glucose–fructose
isomerization) with ionic liquids (Brønsted acid for dehydra-
tion of fructose into HMF) results in 60–80% yield of HMF
HMF is very sensitive to reaction parameters such as sub-
strate, solvent, catalyst and temperature. The reaction is ham-
pered by subsequent transformations of HMF, i.e. formation
of humins or hydrolysis of HMF into levulinic acid and
formic acid. Since some organic solvents stabilize HMF mole-
cules protecting them from destruction, the yield of the prod-
uct depends on the choice of solvent as follows: ionic liquids >
polar organic solvents (especially DMSO) > water. Despite
1
3
based on glucose. The same approach was accomplished by
combining a solid Lewis acid Sn-beta zeolite with a Brønsted
1
4
acid such as HCl or Amberlyst. HMF was obtained in ca.
5
–8
nearly quantitative yields of HMF in ionic liquids
and
60% yield from glucose applying an extraction-assisted pro-
4,9
8,15,16
17
DMSO, these solvents are hardly applicable in large scale
cess
or using organic solvents. Alternatively, a combi-
9
,10
owing to difficulties with recovery of HMF,
high cost and
nation of a basic catalyst for glucose isomerization and acid-
catalyzed dehydration of fructose might be performed in cas-
toxicity. From ecological and economical points of view,
water is the solvent of choice for production of HMF.
1
8
19,20
cade or even one-pot
processes. Definitely, the design
of a heterogeneous catalyst bearing Lewis and Brønsted
acidic sites would be highly desirable considering not only
recyclability, reduced corrosion potential, and waste forma-
tion but also optimized reaction integration for a technical
application. From this point of view, the derivates of
a
Key Laboratory of Polyoxometalate Science of the Ministry of Education, Faculty
of Chemistry, Northeast Normal University, Changchun, 130024, PR China.
E-mail: wangxh665@nenu.edu.cn; Fax: +86 431 85099759; Tel: +86 431 88930042
b
Chair of Heterogeneous Catalysis and Chemical Technology, RWTH Aachen University,
Worringerweg 2, 52074 Aachen, Germany. E-mail: Palkovits@itmc.rwth-aachen.de
2
1–23
HPAs
are suitable candidates for bifunctional catalysts.
†
Electronic supplementary information (ESI) available. See DOI: 10.1039/
c4cy01555j
Lewis acidity can be introduced to HPAs by exchange of
This journal is © The Royal Society of Chemistry 2015
Catal. Sci. Technol.

View Article Online
Paper
Catalysis Science & Technology
protons for transition metals. Such catalysts were successfully
Catalytic experiments
2
4
tested for hydrolysis of cellobiose and cellulose, production
The catalytic experiments were performed under nitrogen
atmosphere in a Parr reactor (volume 50 mL). A mixture of a
monosaccharide (0.3 g) and a given amount of the catalyst
was added into 10 g of solvent. The mixture was stirred and
heated up. The reaction was stopped by rapid cooling of the
reactor in an ice bath. The catalyst Cs Cr SiW12 was sepa-
2 3
rated by centrifugation and rinsed with water three times.
The catalyst was dried at 80 °C for 3 h to remove water.
2
5–28
of biodiesel, and conversion of cellulose into HMF.
Focusing on the synthesis of HMF, we have recently demon-
strated the catalytic activity of dodeca-tungstophosphoric acid
2
9,30
IJH
3
PW12
O
40) and its cesium or silver salts
for the dehy-
dration of fructose or glucose into HMF. Dehydration of fruc-
tose over Ag PW O was performed in a biphasic water/
3
12 40
methylisobutylketone (MIBK) system at 120 °C for 60 min
yielding 78% of HMF. Owing to the Lewis acidity of the cata-
lyst, a transformation of glucose was also possible, but required
harsher conditions: 76% yield of HMF was obtained at 130
Analysis
°
C for 4 h in the same biphasic system. Although HMF can
The consumption of saccharides was measured by means of
high-performance liquid chromatography (HPLC, Shimadzu
LC-10A) conducted on a system equipped with a refractive
index detector. The saccharides were quantified by HPLC
with an Aminex HPX-87H column, using MilliQ water (pH =
be produced in rather high yield in the biphasic system, it
would be advantageous to elaborate a bifunctional catalyst
with Lewis-Brønsted acidity for the manufacture of HMF
in aqueous medium. Cs ijCr OIJOOCC H ) IJH O) ] ijα-SiW O ]
2
3
2
5 6
2
3 2
12 40
−
1
IJCs
2
Cr
3
SiW12), a chromium-based polyoxometalate (POM)
5.5) as the mobile phase at a flow rate of 0.6 mL min and a
column temperature of 30 °C. The concentration of HMF in
aqueous phase was determined by HPLC with an ION-300H
column using a 2 : 8 v/v methanol : water (pH = 2) eluent at a
ionic crystal, is a suitable candidate for water-tolerant catalyst
for HMF synthesis. Chromium atoms are responsible for the
Lewis acidity of this catalyst, while the Brønsted acidity can
be generated from the HPA molecules' dissociation of coordi-
nated water under the polarizing effect of the cation.
2 3
Cs Cr SiW12 was firstly reported by the Mizuno group as a
channel-selective material with hydrophilic and hydrophobic
pores. The narrowest and widest openings of the hydropho-
bic channel are 4.0 Å and 5.2 Å, respectively. Importantly,
incorporation of Cr into the easily separable solid catalyst
diminishes the hazardous effect of Cr . Therefore, in this
work, we tested Cs Cr SiW12 as catalyst for HMF formation
−
1
flow rate of 0.7 mL min and a column temperature of 30 °C
using a UV detector. The concentration of HMF in the
organic phases was determined by gas chromatography using
an Agilent 6890 system equipped with an Agilent 19091J-416
capillary column and a flame ionization detector. Qualitative
analysis was performed by gas chromatography-mass spectro-
metry (GC-MS, Agilent 5970) with scan parameters as follows:
low mass 20.0, high mass 700.0, and threshold 150.
3
1
3
2
3
+
2
3
based on fructose and glucose as substrates in combination
with DMSO and water as solvents.
Results and discussion
Fructose dehydration reactions
The heteropoly acids Cs Cr SiW and H SiW O were char-
2
3
12
4
12 40
Experimental
Catalyst preparation and investigation
acterized and studied as catalysts for fructose dehydration
into HMF. H SiW12 40 is a soluble Brønsted acid with an
acid content of 1.34 mmol g . Cs Cr SiW is a solid
4
O
−
1 37
Solvents and reagents were obtained from commercial
sources and were used without further purification.
2
3
12
bifunctional catalyst with dual Brønsted-Lewis acidity. The
contents of Brønsted acid and Lewis acid sites were obtained
3
3,34
H
4
SiW12
O
40 was prepared following literature studies.
was prepared
according to a previously reported procedure. IR spectra
3
8
Cs ijCr OIJOOCC H ) IJH O) ] ijα-SiW O ]
from titration and the FT-IR spectra of pyridine absorption.
The Brønsted acidity of Cs Cr SiW evaluated by means of
2
3
2
5 6
2
3 2
12 40
3
2
2
3
12
−
1
−1
(4000–400 cm ) were recorded in KBr discs on a Nicolet
sorption of p-nitroaniline is equal to 0.89 mmol g , while
the Lewis acidity of 0.54 mmol g was estimated from the
ratio of the intensities of peaks corresponding to Brønsted
sites at 1540 and 1639 cm and those corresponding to
Lewis sites at 1450 and 1610 cm in the IR spectra of pyri-
dine adsorption. Similar concentrations of acidic sites were
−
1
Magna 560 IR spectrometer. Elemental analyses were carried
out using a Leeman Plasma Spec (I) ICP-ES. The data on ele-
mental analysis reveal a good agreement of the calculated
composition for Cs ijCr OIJOOCC H ) IJH O) ] ijα-SiW O ]
−
1
−
1
2
3
2
5 6
2
3 2
12 40
(W, 48.78; Cr, 6.90; Cs, 5.88; Si, 0.62 wt.%) with the obtained
results (W, 49.37; Cr, 6.83; Cs, 5.85; Si, 0.61 wt.%).
2 3 4 2 3
found for Cs Cr SiW12 and H SiW12O40. Cs Cr SiW12 con-
Acidity of Cs Cr SiW was evaluated by a combination of
tains hydrophilic channels with diameters comparable with
the dimensions of fructose (ca. 5 Å). Therefore we expected
2
3
12
3
5,36
39
spectroscopic and Hammett methods.
A sample of cata-
lyst (100 mg) and Hammett indicator IJ p-nitroaniline, 50 mg)
fructose to be adsorbed in these micropores. The IR spectra
of Cs Cr SiW and the spectra after adsorption of fructose
were dispersed in H O (20 mL). The mixture was sealed,
2
2
3
12
stirred for 12 h at room temperature and subsequently sepa-
rated by filtration. The concentration of p-nitroaniline in the
filtrate was measured by using a Cary 500 UV/Vis/NIR
spectrophotometer at λ = 380 nm.
confirmed the adsorption of the substrate on the catalyst
−
1
(Fig. S1†). IR vibration bands at 982 cm (νas W–O
oxygen bonding to W atom), 920 cm (νas Si–O), 876 cm
d
, terminal
−
1
−1
−
1
(νas W–O , edge-shared oxygen connecting W), 792 cm
b
Catal. Sci. Technol.
This journal is © The Royal Society of Chemistry 2015

View Article Online
Catalysis Science & Technology
Paper
(
νas W–O , corner-shared oxygen connecting W O units),
acidic catalysts is expected, taking into account the high
c
3 13
−
1
4,9
and 540 cm (νas Cr–O) were detected for the parent material
Cs Cr SiW12 (Fig. S1b†). shift to higher frequencies
occurred after adsorption of fructose (Fig. S1a†) with 984
cm , 936 cm , and 878 cm and a wide band located at 738
to 806 cm indicating an interaction between fructose and
the SiW O anion. We screened the catalytic activity of
reactivity and tendency of HMF to resinification.
Fig. 2
2
3
A
shows temperature- and time-dependent HMF yields over
Cs Cr SiW in aqueous medium. The trends observed for
2
3
12
−
1
−1
−1
DMSO are in agreement with the findings for the water-based
system. In both solvents, the highest yields of HMF are
reached at 130 °C within 1.5–2 h and equal 83% and 48% in
DMSO and water, respectively. Longer reaction times do not
improve the formation of HMF, mainly due to catalyst deacti-
vation (at T < 130 °C) or preferential formation of soluble
polymers and humins (at T > 130 °C).
−
1
1
2 40
Cs Cr SiW and H SiW O using water, DMSO and MIBK
2
3
12
4
12 40
as solvents at 130 °C for 30 min (Table 1). The conversion of
fructose is nearly the same for all solvents with a decreasing
selectivity for HMF in the following order: DMSO > MIBK >
water. This tendency is not surprising as DMSO is known to
stabilize HMF, while water gives rise to levulinic and formic
acids as by-products.
active compared to Cs
acidity. Nevertheless, a comparable conversion of fructose in
the presence of both HPAs indicates Cs Cr SiW as a very
Literature reports suggest that HMF yield and selectivity
depend on the starting fructose concentrations (Fig. 3). The
formation of humins is one of the side reactions of fructose
dehydration. The yield of humins can be as high as 35% for
18 wt.% fructose solution and 20% for 4.5 wt.% fructose solu-
4
,9
H SiW O was more catalytically
4 12 40
2
Cr
3
SiW12 owing to the higher Brønsted
9
tion. Surprisingly, the HPA is catalytically active and pro-
2
3
12
promising solid catalyst for this process.
duces HMF in nearly equal yields based on fructose concen-
trations as high as 30 wt.%. The reactions were performed at
130 °C for 30 min with yields of HMF in DMSO and water of
ca. 45% and 34%, respectively. A further increase of the fruc-
tose concentration to 50 wt.% results in a decrease of the
HMF yield accompanied by extensive formation of a brown
precipitate. Nevertheless, even when using 50 wt.% of sub-
strate, a rather high catalytic activity of Cs Cr SiW is
Taking into account that the subsequent hydration of
+
HMF is catalyzed by H , optimization of the Brønsted acidic
functionality is an important factor for HMF selectivity. We
presumed that HMF is more stable in the presence of solid
Cs Cr SiW12 than over highly acidic soluble H SiW12O .
2 3 4 40
Fig. 1 shows that the decomposition of HMF into levulinic
acid and formic acid slows down over Cs Cr SiW compared
2
3
12
2
3
12
to H
Cs Cr
tection of HMF, as the less polar HMF molecule exhibits a
4
SiW12
O
40. Moreover, the hydrophobic channels of the
observed.
2
3
SiW12 ionic crystal probably also contribute to the pro-
4
0
Glucose dehydration reactions
high affinity for hydrophobic sorption sites.
The activity of Cs Cr SiW12 for fructose dehydration was
2
3
HMF production from glucose is more challenging compared
to that from fructose. Thus, a Brønsted acid such as
H SiW O demonstrates poor catalytic activity for the con-
studied at different temperatures and reaction times using
DMSO as solvent (Fig. S2†). The reaction was carried out at
4
12 40
1
10, 120, 130 and 140 °C. Increasing temperature accelerates
version of glucose, producing HMF in yields of 10–29% in
DMSO and 8–14% in an aqueous medium (Fig. 4). Owing to
the presence of chromium in the framework, Cs Cr SiW
the dehydration of fructose. Interestingly, at 110 and 120 °C
the reaction stops after 2 h at a fructose conversion of ca.
2
3
12
7
5% and further increasing the reaction time does not signif-
can serve as a bifunctional catalyst with Brønsted and Lewis
acidity. The yield of HMF in the presence of Cs Cr SiW is
icantly improve the conversion pointing towards deactivation
of the catalyst. Probably, at temperatures lower than 130 °C
the organic substrates or/and products are strongly adsorbed
on the surface of the catalyst causing deactivation. For higher
temperatures, desorption is enhanced, and at 130 and 140 °C,
full conversion of fructose can be achieved within 1.5 h.
Interestingly, degradation of HMF was observed for tempera-
tures above 130 °C, while the product was stable at a lower
temperature. Decomposition of HMF in the presence of
2
3
12
much higher than over H SiW O and reaches ca. 56% and
4
12 40
48% in DMSO and water, respectively. The optimal condi-
tions for the reaction are 140 °C and 4 h. Interestingly, the
HMF yield in DMSO considerably decreases from 83% to
56% when using glucose as substrate instead of fructose. At
the same time, the HMF yield is the same (48%) for both sub-
strates when water serves as solvent. In addition to HMF,
levulinic and formic acids were detected by HPLC as by-
Table 1 The activity and selectivity of different catalysts for fructose dehydrationa
Catalysts
SiW12
Solvent
Conversion (%)
Yield (%)
Selectivity (%)
H
4
O
40
DMSO
MIBK
Water
DMSO
MIBK
Water
87.6
89.2
91.4
76.6
78.3
73.2
47.3
44.9
19.7
45.1
36.2
33.4
54.0
50.3
21.5
58.9
46.2
45.6
Cs Cr SiW12
2 3
a
Reaction conditions: 0.3 g of fructose, 0.007 mmol of catalyst, 10 g of solvent, 130 °C, 30 min.
This journal is © The Royal Society of Chemistry 2015
Catal. Sci. Technol.

View Article Online
Paper
Catalysis Science & Technology
2 3 4
Fig. 1 Stability of HMF over (left) Cs Cr SiW12 and (right) H SiW12O40 catalysts at 130 °C.
Fig. 2 Influence of temperature and reaction time at 130 °C on conversion of fructose. Reaction conditions: 0.3 g of fructose, 0.007 mmol of
catalyst, 10 g of water, 130 °C, 30 min.
Fig. 3 Influence of initial concentration of fructose on HMF yield in water and DMSO solvents. Reaction conditions: 10 g of solvent, 0.007 mmol
of catalyst, 130 °C, 30 min.
products. Moreover, formation of humins was observed.
Overall, these results emphasize the excellent efficiency of
Cs Cr SiW for isomerization of glucose into fructose in
2 3 12
aqueous medium. However, the productivity of fructose
Catal. Sci. Technol.
This journal is © The Royal Society of Chemistry 2015

View Article Online
Catalysis Science & Technology
Paper
Fig. 4 Glucose conversion and HMF yield in the presence of Cs
2
Cr
3
SiW12 and H
4
SiW12O
40. Reaction conditions: 0.3 g of glucose, 10 g of solvent,
0
.056 mmol of catalyst, 4 h.
formation over Cs
2
Cr
3
SiW12 in DMSO is obviously much
fructose in DMSO (Fig. 5) and water (Fig. 6) with only a
minor decrease in catalytic activity. The leaching of
Cs Cr SiW into water after five recycling runs of the cata-
lower than in water. Remarkably, a sole bifunctional catalyst
Cs Cr SiW enables the aqueous-phase production of HMF
2
3
12
2
3
12
based on glucose in yields of 48% compared to a maximum
of 60% yield reported in the literature for rather complex sys-
tems composed of mixtures of a Lewis acid, a Brønsted acid,
a saturated aqueous solution of NaCl, and an organic solvent
lyst was ca. 4.7 wt.% determined by UV-spectroscopy. The IR
spectrum of the recycled Cs Cr SiW12 (Fig. S1c†) basically
corresponds to the parent material. It contains the vibration
2
3
−
1
−1
bands at νas(W–O) 976 cm , νas(W–O–W) 896 cm , νas(W–O–W)
1
5,16
−1
−1
for reactive extraction of HMF.
806 cm and νas(Cr–O) 521 cm , indicating that the original
frameworks of HPAs are not destroyed after the reaction.
However, some shifts of the bands in the IR spectrum and
the appearance of new bands indicate minor structural
changes. For instance, we failed to identify the position of
a weak band corresponding to νas(Si–O) and located at ca.
Reusability of the catalyst
Recyclability is a crucial parameter of a catalyst. Cs Cr SiW
12
2
3
was separated from the product mixture by centrifugation
and reused after washing with water. The catalyst was suc-
cessfully recycled 5 times for synthesis of HMF based on
−
1
920 cm . Nevertheless, the catalytic activity of the material
was not dramatically affected by recycling. Probably, these
changes in IR spectrum take place due to strong adsorption
Fig. 5 Catalyst activity in five reaction cycles. Reaction conditions: 0.3 g
of fructose, 10 g of DMSO, 0.007 mmol of catalyst, 130 °C, 90 min.
Fig. 6 Catalyst activity in five reaction cycles. Reaction conditions: 0.3 g
of fructose, 10 g of water, 0.007 mmol of catalyst, 130 °C, 90 min.
This journal is © The Royal Society of Chemistry 2015
Catal. Sci. Technol.

View Article Online
Paper
Catalysis Science & Technology
of fructose or products. The future work will aim to search References
for a more efficient regeneration procedure for Cs Cr SiW
12
2
3
than washing with water. Noteworthy, ease at recycling of the
solid Cs Cr SiW is a great advantage of this catalyst over
1 M. A. Harmer, A. Fan, A. Liauw and R. K. Kumar, Chem.
Commun., 2009, 6610–6612.
2
3
12
classical HPAs. For example, we failed to perform a recyclabil-
ity test of H SiW12 40 which is soluble in high-boiling DMSO.
Moreover H SiW O is not sufficiently soluble in potential
extracting solvents (e.g. diethyl ether), therefore cannot be
easily isolated.
To investigate whether the catalytic process is homoge-
neously or heterogeneously catalyzed, a leaching test was
2 3
performed. Cs Cr SiW12 was thermostated at 130 °C in aque-
2 Y. Román-Leshkov, J. N. Chheda and J. A. Dumesic, Science,
2006, 312, 1933–1937.
3 M. E. Zakrzewska, E. Bogel-Łukasik and R. Bogel-Łukasik,
Chem. Rev., 2011, 111, 397–417.
4 A. A. Rosatella, S. P. Simeonov, R. F. M. Frade and C. A. M.
Afonso, Green Chem., 2011, 13, 754–793.
5 G. Yong, Y. G. Zhang and J. Y. Ying, Angew. Chem., Int. Ed.,
2008, 47, 9345–9348.
4
O
4
12 40
ous medium for 90 minutes without addition of fructose.
Afterwards the catalyst was separated from the liquid phase
by centrifugation. Then fructose was added to the aqueous
supernatant, and the reaction was carried out for 30 min at
6 M. E. Zakrzewska, E. Bogel-Łukasik and R. Bogel-Łukasik,
Energy Fuels, 2010, 24, 737–745.
7 I. J. Kuo, N. Suzuki, Y. Yamauchi and K. C.-W. Wu, RSC Adv.,
2013, 3, 2028–2034.
1
1
30 °C resulting in fructose conversion and HMF yields of
1.8% and 3.5%, respectively. Conversion of fructose and yield
8 Y. Y. Lee and K. C.-W. Wu, Phys. Chem. Chem. Phys.,
2012, 14, 13914–13917.
of HMF in the blank experiment without HPA were 11.4% and
.2%, accordingly. This result demonstrates that Cs Cr SiW12
catalyzes dehydration of fructose heterogeneously.
9 B. F. M. Kuster, Starch/Staerke, 1990, 42, 314–321.
10 I. Delidovich, K. Leonhard and R. Palkovits, Energy Environ.
Sci., 2014, 7, 2803–2830.
3
2
3
1
1
1 P. Vinke and H. van Bekkum, Starch/Staerke, 1992, 44, 90–96.
2 P. Dornath and W. Fan, Microporous Mesoporous Mater.,
Conclusion
2
014, 191, 10–17.
The heteropoly acid ionic crystal Cs Cr SiW has been stud-
13 J. B. Binder and R. T. Raines, J. Am. Chem. Soc., 2009, 131,
1979–1985.
14 I. I. Ivanova and E. E. Knyazeva, Chem. Soc. Rev., 2013, 42,
3671–3688.
2
3
12
ied as a catalyst for the selective conversion of fructose and
glucose into HMF in DMSO and water. The activity of
Cs Cr SiW is comparable to that of H SiW O for dehy-
2
3
12
4
12 40
dration of fructose to HMF. However, HMF is more stable in
the presence of Cs Cr SiW12 than over H SiW12 40 owing to
15 E. Nikolla, Y. Román-Leshkov, M. Moliner and M. E. Davis,
ACS Catal., 2011, 1, 408–410.
2
3
4
O
lower Brønsted acidity of the former and possible stabiliza-
tion of low polar HMF molecules in the hydrophobic chan-
nels of the ionic crystal. Cs Cr SiW12 produces HMF in high
2 3
16 Y. J. Pagán-Torres, T. F. Wang, J. M. R. Gallo, B. H. Shanks
and J. A. Dumesic, ACS Catal., 2012, 2, 930–934.
17 J. M. R. Gallo, D. M. Alonso, M. A. Mellmer and J. A.
Dumesic, Green Chem., 2013, 15, 85–90.
18 L. Weisgerber, S. Palkovits and R. Palkovits, Chem. Ing.
Tech., 2013, 85, 512–515.
19 W. H. Peng, Y. Y. Lee, C. Wu and K. C.-W. Wu, J. Mater.
Chem., 2012, 22, 23181–23185.
20 A. Takagaki, M. Ohara, S. Nishimura and K. Ebitani, Chem.
Commun., 2009, 6276–6278.
yields based on fructose solutions with initial concentrations
of 3–30 wt.%. Temperatures higher than 130 °C are required
to avoid deactivation of the catalyst via strong adsorption of
the substrate and/or products. The yields of HMF from fruc-
tose and glucose in DMSO media are 83% and 56%, respec-
tively. The catalyst is very active in aqueous medium produc-
ing HMF from glucose and fructose in nearly the same yield
of 48%. This result suggests Cs Cr SiW as a very efficient
21 K. Suzuki, M. Sugawa, Y. Kikukawa, K. Kamata, K. Yamaguchi
and N. Mizuno, Inorg. Chem., 2012, 51, 6953–6961.
22 C. Boglio, G. Lemière, B. Hasenknopf, S. Thorimbert, E. Lacôte
and M. Malacria, Angew. Chem., Int. Ed., 2006, 45, 3324–3327.
2
3
12
catalyst for aqueous-phase glucose-based synthesis of HMF.
The catalyst was recycled 5 times with only minor loss of
activity.
2
3 Y. Ogasawara, S. Itagaki, K. Yamaguchi and N. Mizuno,
ChemSusChem, 2011, 4, 519–525.
Acknowledgements
2
4 K. Shimizu, H. Furukawa, N. Kobayashi, Y. Itayab and A.
Satsumaa, Green Chem., 2009, 11, 1627–1632.
This work was supported by the National Natural Science
Foundation of China (20871026, 21371029 and 21171032), by
25 S. Zhao, M. X. Cheng, J. Z. Li, J. Tian and X. H. Wang, Chem.
Commun., 2011, 47, 2176–2178.
“the Fundamental Research Funds for the Central Universities”
(
10JCXK011), and by the major projects of Jilin Provincial
26 J. Li, X. Wang, W. Zhu and F. Cao, ChemSusChem, 2009, 2,
177–183.
27 J. Zhao, H. Guan, W. Shi, M. Cheng, X. Wang and S. Li,
Catal. Commun., 2012, 20, 103–106.
28 W. Shi, J. Zhao, Y. Xin, S. T. Wang, X. H. Wang and M. X.
Huo, Chem. Eng. Technol., 2012, 35, 347–352.
Science and Technology Department (20100416, 201105001,
and 20140204085GX). Xiaohu Yi thanks the China Scholar-
ship Council for financial support. Irina Delidovich thanks
the Alexander von Humboldt Foundation and the Bayer
Foundation for financial support.
Catal. Sci. Technol.
This journal is © The Royal Society of Chemistry 2015

View Article Online
Catalysis Science & Technology
Paper
2
3
9 C. Y. Fan, H. Y. Guan, H. Zhang, J. H. Wang, S. T. Wang and
X. H. Wang, Biomass Bioenergy, 2011, 35, 2659–2665.
0 Q. Zhao, L. Wang, S. Zhao, X. H. Wang and S. T. Wang, Fuel,
35 T. Okayasu, K. Saito, H. Nishide and M. T. W. Hearn, Green
Chem., 2010, 12, 1981–1989.
36 C. Thomazeau, H. Olivier-Bourbigou, L. Magna, S. Luts and
B. Gilbert, J. Am. Chem. Soc., 2003, 125, 5264–5265.
37 F. J. Berry, G. R. Derrick, J. F. Marco and M. Mortimer,
Mater. Chem. Phys., 2009, 114, 1000–1003.
2
011, 90, 2289–2293.
3
3
1 H. Yamamoto, Proc. Jpn. Acad., Ser. B, 2008, 84, 134–146.
2 A. Lesbani, R. Kawamoto, S. Uchida and N. Mizuno, Inorg.
Chem., 2008, 47, 3349–3357.
38 S. H. Zhu, X. Q. Gao, F. Dong, Y. L. Zhu, H. Y. Zheng and
Y. W. Li, J. Catal., 2013, 306, 155–163.
3
3 A. Teze, G. Herve, R. Finke and D. K. Lyon, Inorg. Synth.,
1
990, 27, 85–96.
39 R. Rinaldi and F. Schuth, Energy Environ. Sci., 2009, 2, 610–626.
40 C. Detoni, C. H. Gierlich, M. Rose and R. Palkovits, ACS
Sustainable Chem. Eng., 2014, 2, 2407–2415.
3
4 D. Rocchiccioli, M. Fournier, R. Franck and R. Thouvenot,
Inorg. Chem., 1983, 22, 207–216.
This journal is © The Royal Society of Chemistry 2015
Catal. Sci. Technol.