Bifunctional ZSM-5/hydrotalcite composite for enhanced production of 5-hydroxymethylfurfural from glucose

Article abstract of DOI:10.1039/c9nj00462a

We describe herein the preparation of ZSM-5/hydrotalcite composites and their catalytic activity for the formation of 5-hydroxymethylfurfural (5-HMF) from glucose. The composites with high surface area and sufficiency in both acidity and basicity were achieved by the hydrothermal and dry gel methods, denoted as ZSM-5/HT-hydr and ZSM-5/HT-dg, respectively. Used as a combined solid acid-base catalyst in a biphasic H₂O/THF/NaCl system, the ZSM-5/HT composites showed excellent bifunctional catalytic activities since the base sites on HT promoted an isomerization of glucose to fructose, while the acid sites on ZSM-5 enhanced a successive dehydration of fructose to 5-HMF. Under the optimized reaction conditions, this catalytic process provided over 90% glucose conversion with >65% yield of 5-HMF at 150 °C for 120 min and 0.1:1 mass ratio of catalyst to glucose. Even through both ZSM-5/HT composites exhibited a comparable catalytic performance, ZSM-5/HT-hydr was more stable, selective, reusable, and preferable for one-pot synthesis of 5-HMF from glucose in the studied conditions.

Full text of DOI:10.1039/c9nj00462a

View Article Online
View Journal
NJC
Accepted Manuscript
This article can be cited before page numbers have been issued, to do this please use: M. Subsadsana, K.
Miyake, K. Ono, M. Ota, Y. Hirota, N. Nishiyama and S. Sansuk, New J. Chem., 2019, DOI:
10.1039/C9NJ00462A.
This is an Accepted Manuscript, which has been through the
Volume 40 Number
1 January 2016 Pages 1–846
Royal Society of Chemistry peer review process and has been
accepted for publication.
NJC
Accepted Manuscripts are published online shortly after
New Journal of Chemistry
www.rsc.org/njc
A journal for new directions in chemistry
acceptance, before technical editing, formatting and proof reading.
Using this free service, authors can make their results available
to the community, in citable form, before we publish the edited
article. We will replace this Accepted Manuscript with the edited
and formatted Advance Article as soon as it is available.
You can find more information about Accepted Manuscripts in the
author guidelines.
Please note that technical editing may introduce minor changes
to the text and/or graphics, which may alter content. The journal’s
standard Terms & Conditions and the ethical guidelines, outlined
in our author and reviewer resource centre, still apply. In no
event shall the Royal Society of Chemistry be held responsible
for any errors or omissions in this Accepted Manuscript or any
consequences arising from the use of any information it contains.
ISSN 1144-0546
PAPER
Jason B. Benedict et al.
The role of atropisomers on the photo-reactivity and fatigue of
diarylethene-based metal–organic frameworks
rsc.li/njc

Page 1 of 9
New Journal of Chemistry
1
2
3
4
View Article Online
DOI: 10.1039/C9NJ00462A
New Journal of Chemistry
5
6
7
8
9
PAPER
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Bifunctional ZSM‐5/hydrotalcite composite for enhanced
production of 5‐hydroxymethylfurfural from glucose
Maliwan Subsadsana,*,a Koji Miyake,b Kaito Ono,b Misaki Ota,b Yuichiro Hirota,b Norikazu
Nishiyama,b and Sira Sansuk *,c
Received 00th January 2019,
Accepted 00th January 2019
DOI: 10.1039/x0xx00000x
www.rsc.org/
We describe herein the preparation of ZSM‐5/hydrotalcite composites and their catalytic activity for the formation of 5‐
hydroxymethylfurfural (5‐HMF) from glucose. The composites with high surface area and sufficiency in both acidity and
basicity were achieved by the hydrothermal and dry gel methods, denoted as ZSM‐5/HT‐hydr and ZSM‐5/HT‐dg,
respectively. Used as a combined solid acid‐base catalyst in a biphasic H2O/THF/NaCl system, the ZSM‐5/HT composites
showed excellent bifunctional catalytic activities since the base sites on HT promoted an isomerization of glucose to
fructose, while the acid sites on ZSM‐5 enhanced a successive dehydration of fructose to 5‐HMF. Under the optimized
reaction conditions, this catalytic process provided over 90% glucose conversion with >65% yield of 5‐HMF at 150°C for
120 min and 0.1:1 mass ratio of catalyst to glucose. Even through both ZSM‐5/HT composites exhibited a comparable
catalytic performance, ZSM‐5/HT‐hydr was more stable, selective, reusable, and preferable for one‐pot synthesis of 5‐HMF
from glucose in the studied condition.
pot system afforded high yield and selectivity for the formation of
1. Introduction
5‐HMF under mild conditions [10]. For instance, the use of
amberlyst‐15 as a solid acid catalyst and hydrotalcite (HT), also
called layered double hydroxides (LDHs), as the solid base catalyst
was reported [11‐13]. The HT catalyst improved the isomerization
of glucose to fructose, while amberlyst‐15 enhanced the
dehydration of fructose to 5‐HMF.
Recently, 5‐Hydroxymethylfurfural (5‐HMF) has received a great
deal of attention since it has been considered as a promising
candidate for the production of high value‐added chemicals and
biofuels [1,2]. This compound can be synthesized by the chemical
conversion of C6 carbohydrates in water over various acid catalysts
such as heteropoly acid, zeolite, and Amberlyst‐15 resin [3]. In
general, 5‐HMF with excellent yields can be directly produced from
fructose using dehydration catalysts [4,5]. However, the high cost of
fructose limits its utilization for large scale production of 5‐HMF.
Many attempts have been made to employ glucose as the starting
material. The production of 5‐HMF from glucose commonly involves
two steps, the isomerization of glucose to fructose and a
subsequent dehydration of fructose to 5‐HMF. Various solid acid
catalysts with good properties, including oxides [6], polymers [7],
and zeolites [8], have been utilized for 5‐HMF production.
In addition to the requirement of solid catalysts with high
activity and stability, the use of highly sustainable and efficient
reaction solvents is desirable. Many attempts have been made for
the production of 5‐HMF from glucose in different solvents
including water [14,15], ionic liquids [16,17], and organic solvents
[18]. Recently, the conversion of glucose in the biphasic system has
been developed to facilitate the 5‐HMF formation as well as the
minimization of side reactions toward 5‐HMF [19]. For example,
62% yield of 5‐HMF was produced from glucose over AlCl3 catalyst
and HCl in biphasic water‐alkylphenol system [20]. It was reported
that a 61% 5‐HMF from glucose was obtained over AlCl3 catalyst in a
biphasic system with THF as an extracting solvent [21,22]. Also, Sn‐
Beta zeolite in H2O/THF/NaCl system increased the selectivity with
57% yield of 5‐HMF at 79% conversion of glucose [23].
It has also been reported that the transformation of glucose
into fructose can be enhanced by using a base [9]. This concept
provides an alternative approach for the formation of 5‐HMF from
glucose through a two‐step reaction by using a mixed solid acid‐
base catalyst. Using both solid acid and base catalysts in the one‐
This study describes the synthesis of ZSM‐5/HT composites by
the hydrothermal and dry gel methods. These composites were
utilized as a combined solid acid/base catalyst in a one‐pot
conversion of glucose into 5‐HMF in a biphasic H2O/THF/NaCl
solvent system. The catalytic performance of ZSM‐5/HT composites
was evaluated and compared in terms of glucose conversion and 5‐
HMF yield as well as recyclability. Also, the influence of various
factors such as catalyst type, reaction time and temperature, and
a. Program of Chemistry, Faculty of Science and Technology, Nakhon Ratchasima
Rajabhat University,Nakhon Ratchasima 30000, Thailand. E‐mail:
Suebsadsana@gmail.com
b. Division of Chemical Engineering, Graduate School of Engineering Science, Osaka
University, 1‐3 Machikaneyama, Toyonaka, Osaka 560‐8531, Japan
c. Materials Chemistry Research Center, Department of Chemistry and Center of
Excellence for Innovation in Chemistry, Faculty of Science, Khon Kaen University,
Khon Kaen 40002, Thailand. E‐mail: sirisan@kku.ac.th
This journal is © The Royal Society of Chemistry 2019
New J. Chem., 2019, 00, 1‐8 | 1

New Journal of Chemistry
Page 2 of 9
PAPER
New Journal of Chemistry
1
2
3
4
5
6
7
8
9
mass ratio of catalyst to glucose on the catalytic activities of the emission microscope operating at 15 kV. Transmission electron
View Article Online
DOI: 10.1039/C9NJ00462A
synthesized composites was investigated and optimized.
microscopy (TEM) images were recorded on a Hitachi H‐800
microscope operating at 200 kV. N2 adsorption‐desorption
experiment was performed at ‐196 °C using a BELSORPmax
(MicrotracBEL) surface area and pore size analyzer. Before the
measurements, catalysts were outgassed at 300 °C for 2 h. The
brunauer‐emmett‐teller (BET) method was used to calculate the
surface areas using the adsorption data in the relative pressure
(P/P0) range of 0.05‐0.25. The pore volume and pore size
distribution were obtained by the Barrett‐Joyner‐Halenda (BJH)
method. The acidity and basicity of the catalysts were determined
by NH3‐TPD and CO2‐TPD, respectively. The NH3 or CO2 adsorption
was carried out at 45 °C with 1% NH3/He or CO2/He at 30 mL min‐1
for 30 min, followed by purging with He for 1 h. The desorption of
chemisorbed NH3 or CO2 was done by heating up to 600 °C at 10 °C
min‐1 under He flow at 30 mL min‐1.
2.
Experimental
2.1.
Materials
The protonic H‐ZSM‐5 zeolite with Si/Al ratio of 25 was purchased
from Tosoh Corp. D‐fructose, hydroxymethylfurfural (5‐HMF),
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
tetrahydrofyran
(THF),
magnesium
nitrate
hexahydrate
(Mg(NO3)2.6H2O), sodium chloride (NaCl),
aluminum nitrate
nonahydrate (Al(NO3)3.9H2O), sodium carbonate (Na2CO3), and
sodium hydroxide (NaOH) were purchased from Sigma‐Aldrich,
USA. D‐glucose was obtained from Ajax Finechem Pty Ltd.
Acetonitrile (99%) was procured from CARLO ERBA reagent. Sulfuric
acid (98%) was obtained from AR‐RCI Labscan.
2.2.
Synthesis of catalysts
2.4.
Catalytic activity evaluation
HT was first synthesized using 3:1 molar ratio of Mg: Al by the co‐
precipitation method as explained elsewhere [24]. Typically, a
solution containing 13.85 g of Mg(NO3)26H2O and 6.60 g of
Al(NO3)39H2O in 200 mL DI was prepared. Then, 150 mL of an
aqueous solution of 4.45 g Na2CO3 was added slowly under stirring
at room temperature and then 3 M NaOH was added to adjust to
pH 12. The mixture was then transferred into the Teflon coated
In a typical experiment, 1 g of glucose was dissolved in a biphasic
solvent system containing 2:1 water to THF volume ratio, 10 mL of
40 g NaCl in 100 g of water. After that, 0.1 g catalyst was added into
10 wt.% glucose‐ H2O/THF/NaCl system. The mixture was
transferred into a glass reactor of 50 mL, provided with a screw top
of Teflon‐lined stainless steel and placed in the oil bath at 150 °C,
with a stirring rate of 500 rpm. Other catalytic parameters such as
reaction temperature, reaction time and mass ratio of catalyst and
glucose were tested. After the reaction was stopped, the reactor
was placed in an ice bath. Lastly, the products were separated,
filtered, and analyzed.
stainless steel autoclave for hydrothermal treatment at
a
predefined temperature of 120 °C for 48 h under autogenous water
vapor pressure. After that, the precipitates were filtered, washed
thoroughly with distilled water until the pH of the filtrate reached 7,
and dried in an oven at 90 °C for 24 h.
ZSM‐5/HT composites were prepared by two methods. In the
hydrothermal method, 1 g of ZSM‐5 and 1 g of synthesized HT were
dispersed in 40 mL DI water under constant stirring for 2 h. The
suspension was then transferred into the 100 mL Teflon‐lined
stainless steel autoclave and hydrothermally treated at 120 °C for 24
h. Finally, the product was filtrated, washed with DI water, and dried at
90 °C for 24 h. The obtained composite in this method was denoted as
ZSM‐5/HT‐hydr.
In the dry gel method, the ZSM‐5/HT composite was prepared by
dispersing 1 g of HT and 1 g of ZSM‐5 in 40 mL DI water at a drying
temperature of 90 °C for 24 h. After that, the suspension was
evaporated to obtain a dry gel, then grinded, and put into an
autoclave together with water. The steam treatment was carried
out at 120 °C for 24 h. The resultant powder was washed with DI
water and separated by centrifugation. Finally, the product was
dried at 90 °C for 24 h. The obtained composite from this method
was denoted as ZSM‐5/HT‐dg.
2.5.
Analysis of products
Quantitative analysis of 5‐HMF in both aqueous and organic phases
was carried out by high performance liquid chromatography (HPLC)
using a Shimadzu SCL‐10A VP with an Inertsil ODS‐3 column (4.6
mm x 250 mm, 5 m) and a UV detector at 280 nm. The mobile
phase was water/acetonitrile with a 70/30 volume ratio at a flow
rate of 1.0 mL min‐1. Glucose and fructose concentrations were
determined by HPLC (Agilent) with a refractive index detector and
Zorbax Carbohydrate column (300 mm x 7.8 mm). 5 mM H2SO4
solution at pH 7 was used as the mobile phase at a flow rate of 1.0
mL min‐1 and a column temperature of 40 °C. Samples were diluted
with DI water and filtered through a 0.45 m filter before HPLC
analysis. The glucose conversion, 5‐HMF yield, and selectivity were
determined by using the following equations, respectively.
Glucose conversion (%) = (mole of glucose reacted/moles of
glucose initial) x 100
5‐HMF yield (%) = (mole of 5‐HMF produced/ moles of glucose
initial) x 100
Selectivity (%) = (yield/conversion) x 100
2.3.
Characterization of catalysts
The phase purity and degree of crystallization of the prepared
composites were obtained by X‐ray diffraction (XRD) measurement
using PANalyticalX’Pert‐MPD diffractometer with Cu K ( = 1.5406
Å) radiation (40 kV voltage, 30 mA cathodic current) at a scanning
rate of 0.05 s‐1 in the 2Ɵ range of 5‐80°. Scanning electron
microscopy (SEM) images were obtained using a JSM‐6700F field‐
The measurements were carried out in triplet in each condition and
an average value of both the conversion of glucose, yield of 5‐HMF,
and selectivity was presented.
2 | New J. Chem., 2019, 00, 1‐8
This journal is © The Royal Society of Chemistry 2019

Page 3 of 9
New Journal of Chemistry
New Journal of Chemistry
PAPER
1
2
3
4
5
3.
Results and discussion
View Article Online
DOI: 10.1039/C9NJ00462A
3.1.
Properties of catalysts
6
7
8
9
Fig. 1 shows the XRD patterns of synthesized composites compared
to those of the individuals. It can be seen in Fig. 1a that the XRD
pattern of HT displayed a well‐crystallized structure with the
characteristic diffraction peaks at 2 11, 22, 34, 38, 45, and 61°,
which corresponded to the crystal planes of (003), (006), (009),
(015), (018), and (110), respectively [25]. In Fig.1b, the XRD pattern
showed the characteristic MFI crystal structure of ZSM‐5 with five
diffraction peaks, assigned at 2 = 7.9, 8.8, 23.1, 23.6 and 23.8,
representing (101), (020), (501), (151) and (303) planes, respectively
[26]. In the case of composites shown in Fig. 1c and 1d, ZSM‐5/HT‐
hydr and ZSM‐5/HT‐dg displayed similar XRD patterns, which were
the combined characteristic peaks of ZSM‐5 and HT. However, a
decrease in peak intensity was observed in the composites. These
XRD patterns indicated a successful preparation of the composites
by both the hydrothermal and dry gel methods.
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
SEM images of composites are shown in Fig. 2. In both cases,
ZSM‐5/HT composites exhibited the hexagonal platelet structure
of HT and very uniform crystalline ZSM‐5 zeolite nanoparticles
(~500 nm) with a well‐defined spherical shape. Also, it can be seen
that HT particles attached to the surface of the ZSM‐5 zeolite. This
was possibly due to an electrostatic interaction between the
positively charged surface of HT and negatively charged surface of
ZSM‐5. In Fig. 2b, the deposition of HT particles on the surface of
ZSM‐5 in ZSM‐5/HT‐dg was higher than that in ZSM‐5/HT‐hydr.
Fig. 2 SEM images of composites; (a) ZSM‐5/HT‐hydr and (b) ZSM‐
5/HT‐dg.
Fig. 3 shows TEM images of the ZSM‐5/HT composites. In Fig.
3a for ZSM‐5/HT‐hydr, agglomerated hexagonal particles of well‐
formed, shaped crystals of ZSM‐5 were observable. The ZSM‐5
particles were overlapped with the HT platelets. The hydrothermal
method offered well dispersed particles (approximately 100 nm).
For ZSM‐5/HT‐dg in Fig. 3b, an accumulation of HT particles on the
surface of ZSM‐5 was apparent. Thus, this observation implied that
the dry gel method provided a low dispersion of composite
particles.
Fig. 1 XRD patterns of catalysts: (a) HT, (b) ZSM‐5, (c) ZSM‐5/HT‐ Fig. 3 TEM images of composites; (a) ZSM‐5/HT‐hydr and (b) ZSM‐
hydr, and (d) ZSM‐5/HT‐dg.
5/HT‐dg.
This journal is © The Royal Society of Chemistry 2019
New J. Chem., 2019, 00, 1‐8 | 3

New Journal of Chemistry
Page 4 of 9
PAPER
New Journal of Chemistry
1
2
3
4
View Article Online
DOI: 10.1039/C9NJ00462A
Table 1 Textural properties, total acidity, and total basicity of ZSM‐5, HT, and ZSM‐5/HT composites.
5
6
7
8
catalysts
Stotal
(m2/g)
368
Smicro
(m2/g)
480
Smeso
(m2/g)
61.7
196
Vp (micro)
(cm3/g)
0.102
Vp(meso)
(cm3/g)
0.154
0.743
0.62
dp(micro)
(nm)
0.42
dp(meso)
(nm)
‐
Total acidity
Total basicity
(mmol/g)
‐
(mmol/g)
0.58
‐
ZSM‐5
HT
9
253
79.6
361
0.003
0.60
68.0
44.1
44.0
12.41
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
ZSM‐5/HT‐hydr
ZSM‐5/HT‐dg
551
103
0.052
0.62
0.53
0.51
5.22
444
297
99
0.034
0.51
0.60
6.65
3.2.
Catalytic activity
The surface properties of the synthesized catalysts were
investigated by the BET method. Fig.S1 displays the nitrogen
adsorption‐desorption isotherms and the pore size distribution
of ZSM‐5/HT‐hydr and ZSM‐5/HT‐dg. In Fig. S1a, both
composites presented type I and IV Langmuir isotherms,
indicating an adsorption of microporous ZSM‐5 zeolite and the
existence of a mesoporous structure of HT, respectively. Fig.
S1b and S1c display micropore and mesopore size
distributions, respectively. Compared to ZSM‐5/HT‐hydr, ZSM‐
5/HT‐dg exhibited narrow size distributions. The textural
properties of ZSM‐5, HT, and the synthesized composites are
summarized in Table 1. It was found that the composites had
larger surface area than the starting materials. When
compared with ZSM‐5/HT‐hydr, a decrease in the surface area
and pore volume of ZSM‐5/HT‐dg was noticeable. However,
the particle size of both composites was insignificant. These
results confirmed the SEM and TEM results. The difference in
the surface properties of the composites possibly resulted
from the preparation processes.
First, the mass ratio of ZSM‐5/HT for the preparation of composites
was studied. As shown in Fig. S3, the result showed that the
composites obtained from the weight ratio at 1:1 of ZSM‐5/HT gave
the highest yield of 5‐HMF. At this optimized mass ratio, the results
confirmed that both base and acid sites on ZSM‐5/HT composites
were sufficient for the two‐step reactions in these treatments. The
reaction pathways of glucose conversion to 5‐HMF over the ZSM‐
5/HT catalysts in a biphasic H2O/THF/NaCl system are illustrated in
Scheme 1. The mechanism for the formation of 5‐HMF from
glucose included two steps including an isomerization of glucose to
fructose by the base sites of HT and a successive dehydration of
generated fructose to 5‐HMF by the Brønsted acid sites of ZSM‐5
zeolite. The photographic images of the unfiltered 5‐HMF solution
produced over different catalysts are displayed in Fig. S4. From
chromatographic analysis of the products shown in Fig. S5, high
isolation and purification of 5‐HMF were obtained and no presence
of 5‐HMF was observed in an aqueous phase. The use of THF as an
extracting solvent not only showed the highest partitioning of 5‐
HMF into the organic phase, but also stabilized 5‐HMF and
prevented the formation of levulinic acid. As no formation of
levulinic acid and formic acid was found, our approach provided a
very selective formation of 5‐HMF directly from glucose. Thus, the
rehydration of 5‐HMF to levulinic acid and formic acid was not
included in the reaction pathways.
The acidity of the prepared composites was investigated by the
NH3‐TPD technique. Fig. S1d shows the NH3‐TPD results of ZSM‐
5/HT‐hydr and ZSM‐5/HT‐dg. It can be seen that the profile of ZSM‐
5/HT‐hydr illustrated two broad peaks in the range of 100‐500 °C,
with more weak acidity (100‐300 °C) and medium acidity (350‐500
°C), which were attributed to the desorption of hydrogen‐bonded
NH3 molecules and the decomposition of ionically bonded NH4+ ions
with oxygen atoms of one Keggin unit, respectively [27]. In ZSM‐
5/HT‐dg, a lower peak intensity was observed. Still, another broad
peak (490‐550 °C) was observed in the ZSM‐5/HT‐dg, indicating its
strong acidity. As presented in Table 1, the difference in acidity of
ZSM‐5/HT‐hydr and ZSM‐5/HT‐dg was minimal. Also, the acidities of
both composites were slightly lower than that of ZSM‐5.
In addition, the basicity of composites was studied by the CO2‐
TPD method. The CO2‐TPD profiles of catalysts are presented in Fig.
S2. The result in Table 1 showed that the total basicity of ZSM‐5/HT‐
hydr and ZSM‐5/HT‐dg was reduced significantly, compared with
HT. It was also observed that the basicity of ZSM‐5/HT‐dg was
higher than that of ZSM‐5/HT‐hydr. The results implied that the
synthetic method had an effect on the acidity and basicity of the
composites. This difference in ratio of acidity and basicity of these
prepared composites could possibly lead to a variance in their
catalytic activity for the formation of 5‐HMF from glucose under the
studied condition.
Scheme 1 Conversion of glucose to 5‐HMF by a combined
isomerization and dehydration reaction pathway over bifunctional
ZSM‐5/HT catalyst.
4 | New J. Chem., 2019, 00, 1‐8
This journal is © The Royal Society of Chemistry 2019

Page 5 of 9
New Journal of Chemistry
New Journal of Chemistry
PAPER
1
2
3
4
5
6
7
8
9
3.2.1. Effect of reaction temperature and type of catalysts
their surface properties as well as acidity and basiciVtiyew. AWrtihcleenOntlhinee
DOI: 10.1039/C9NJ00462A
The catalytic activities of various catalysts for the production of 5‐ temperature increased, the conversion of glucose and 5‐HMF yield
HMF from glucose in the biphasic H2O/THF/NaCl system at reaction of composites were increased, probably due to the fact that the
temperatures in the range of 90‐180 °C were investigated, while the base sites on HT promoted the isomerization of glucose into
reaction time was kept at 90 min. The results of the conversion of fructose and the acid sites on ZSM‐5 facilitated the dehydration of
glucose and the yield of 5‐HMF are presented in Fig. 4. It was found fructose to 5‐HMF. However, the decomposition of HT could be
that the reaction temperature and types of catalysts had a considered at a high reaction temperature as it offered the basic
significant influence on the glucose conversion and yield of 5‐HMF. sites on catalysts for the isomerization of glucose to fructose,
It was found that the composites prepared by the hydrothermal resulting in a decreased yield of 5‐HMF as shown in Fig. 4b. Also,
and dry gel methods gave much better catalytic performance than the use of H2O/THF/NaCl solvent could favour the effective
one obtained by a physical mixing. As shown in Fig. 4a, the partition of 5‐HMF into the organic phase, thereby improving the
composites exhibited a higher conversion of glucose than an selectivity for 5‐HMF production.
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
individual catalyst or without a catalyst being used, when the
3.2.2. Effect of reaction time
o
reaction temperature increased. Up to 150 C, the conversion of
The effect of the reaction time on the conversion of glucose and
glucose over the composites attained a high value at almost 80%.
yield of 5‐HMF by ZSM‐5/HT‐hydr and ZSM‐5/HT‐dg was
However, at a higher reaction temperature, the decomposition of 5‐
investigated at 150 oC. As shown in Fig. 5, the reaction time
HMF occurred. This resulted in a reduction in the yield of 5‐HMF, as
influenced the glucose conversion and 5‐HMF yield. In Fig. 5a, both
seen in Fig. 4b. It was obvious that the ZSM‐5/HT‐hydr and ZSM‐
ZSM‐5/HT‐hydr and ZSM‐5/HT‐dg composites reached almost 90%
5/HT‐dg had almost equivalent catalytic activities with the highest
conversion of glucose with over 64% yield of 5‐HMF after 120 min
yields of 5‐HMF of 50 and 48%, respectively, at 150 °C for 90 min. A
of reaction time. In both catalysts, however, the yields of 5‐HMF
slight difference in catalytic activity of composites possibly due to
decreased at 150 min of reaction time, as presented in Fig. 5b.
Fig. 5 Effect of time on (a) the conversion of glucose and (b) yield of
Fig. 4 Effect of reaction temperature and types of catalysts on (a)
5‐HMF using ZSM‐5/HT‐hydr and ZSM‐5/HT‐dg catalysts at the
the conversion of glucose and (b) yield of 5‐HMF at reaction
reaction condition of 1 g of glucose, 10 mL of H2O/THF/NaCl
condition including 1 g of glucose, 10 mL of H2O/THF/NaCl solvent,
solvent, 0.1 g of catalyst, and 150 °C.
0.1 g of catalyst, and 90 min of reaction time.
This journal is © The Royal Society of Chemistry 2019
New J. Chem., 2019, 00, 1‐8 | 5

New Journal of Chemistry
Page 6 of 9
PAPER
New Journal of Chemistry
1
2
3
4
5
6
7
8
9
As the formation rate of 5‐HMF relied on the isomerization of
glucose and dehydration of fructose, a longer reaction time
increased the exposure of 5‐HMF to the secondary reactions, thus
reducing the formation of 5‐HMF, confirmed by the
chromatographic data in Fig. S6 showing the presence of other by‐
products, which could be 2,5‐Dimethylfuran, levolunic acid, or
adipic acid [27,31]. Therefore, 120 min of reaction time was chosen
for further study.
View Article Online
DOI: 10.1039/C9NJ00462A
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
3.2.3. Effect of mass ratio of catalyst and glucose
The influence of mass ratio of catalyst to glucose on the conversion
of glucose into 5‐HMF was also studied and the results are shown in
Fig. 6. Generally, the amount of catalyst played a key role in the
glucose conversion. In Fig. 6a, the highest glucose conversion was
obtained at 0.1:1 or a higher mass ratio of catalyst to glucose.
However, a further increase in the mass of catalysts led to a
decrease in the 5‐HMF yield, as displayed in Fig. 6b. In both ZSM‐
5/HT‐hydr and ZSM‐5/HT‐dg, the maximum yields of 5‐HMF were
achieved at 0.1:1 mass ratio of catalyst to glucose. A decline of 5‐
HMF yield for a higher amount of catalysts used was possibly
associated with a decrease in the selectivity. Hence, 0.1:1 mass
ratio of catalyst to glucose was optimal under this reaction
condition.
Table 2 shows a comparison on the production of 5‐HMF from
glucose over various catalysts used in different biphasic solvent
systems. It was found that the studied system presented
comparable results with the Al‐MCM‐41 catalyst in the H2O/MIBK
system [28]. However, our system was accomplished in a shorter
reaction time and at a lower temperature. Moreover, the
synthesized composite was more active than other catalysts in the
same solvent system [23,31]. When compared with other reaction
systems, the present system offered the highest yield (>65%) of 5‐
HMF with over 90% glucose conversion, and was achieved under
mild conditions. The obtained high yield of 5‐HMF possibly resulted
from the bifunctional properties of ZSM‐5/HT catalysts and the
excellent reaction solvents used. This indicated that the synthesized
Fig. 6 Effect of mass catalyst: glucose ratio on (a) the conversion of
glucose and (b) yield of 5‐HMF using ZSM‐5/HT‐hydr and ZSM‐5/HT‐
dg catalysts in the reaction condition of 1 g of glucose, 10 mL of
H2O/THF/NaCl solvent, 150 °C, and 120 min.
ZSM‐5/HT composite was an excellent catalyst for the efficient
conversion of glucose into 5‐HMF in a one‐pot biphasic
reactor.
3.3.4. The reusability of ZSM‐5/HT catalyst
The recyclability and stability are important factors to evaluate the
efficiency of the prepared catalysts. Accordingly, the reusability of
ZSM‐5/HT catalysts for five successive reaction runs was studied.
Table 2 Overview on the performance of various catalysts for the conversion of glucose to 5‐HMF in biphasic solvent system.
Catalyst
Solvent
Temperature (oC)
Time (min)
Conversion (%) Yield (%)
Ref.
20
26
28
29
30
23
31
AlCl3 /HCl
TaOPO4
H2O/SBP
170
170
195
195
180
180
160
40
60
88
56
62
33
63
42
55
57
59
H2O/MIBK
Al‐MCM‐41 silica
ZSM‐5 zeolite
Beta zeolite
H2O/MIBK
150
30
>99
80
H2O/MIBK/NaCl
H2O/THF/DMSO
H2O/THF/NaCl
H2O/THF/NaCl
180
70
78
Sn‐Beta zeolite/HCl
Nb/C‐50
79
240
98
ZSM‐5/HT‐dg
ZSM‐5/HT‐hydr
H2O/THF/NaCl
H2O/THF/NaCl
150
150
120
120
90
92
64
67
this
work
Catalyst reusability after five runs
ZSM‐5/HT‐dg
ZSM‐5/HT‐hydr
H2O/THF/NaCl
H2O/THF/NaCl
150
150
120
120
60
62
27
42
2‐ sec‐butylphenol (SBP), tetrahydrofuran (THF), methyl isobutyl ketone (MIBK), dimethylsulfoxide (DMSO)
6 | New J. Chem., 2019, 00, 1‐8
This journal is © The Royal Society of Chemistry 2019

Page 7 of 9
New Journal of Chemistry
New Journal of Chemistry
PAPER
1
2
3
4
View Article Online
DOI: 10.1039/C9NJ00462A
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Fig. 8 SEM images of (a) ZSM‐5/HT‐hydr and (b) ZSM‐5/HT‐dg
catalysts after five catalytic runs.
Fig. 7 The reusability of catalysts; (a) yield of 5‐HMF and (b)
selectivity for each consecutive run at the reaction condition of 1 g
of glucose, 10 mL of H2O/THF/NaCl solvent, 150 °C, 120 min, and
0.1 g of catalyst.
Fig. 9 XRD patterns of (a) ZSM‐5/HT‐hydr before use and the spent
catalysts; (b) ZSM‐5/HT‐hydr and (c) ZSM‐5/HT‐dg after five
catalytic runs.
indicated that ZSM‐5/HT‐hydr was more stable than ZSM‐5/HT‐dg
in the studied system. Thus, ZSM‐5/HT‐hydr was more suitable for
one‐pot synthesis of 5‐HMF from glucose in this biphasic system.
After each reaction run, the ZSM‐5/HT catalyst was washed, and
dried at 110 oC for 6 h and reused in the next run. The performance
was reported in terms of yield of 5‐HMF and selectivity as depicted More importantly, H2O/THF/NaCl solvent not only facilitated the
in Fig. 7. In Fig. 7a, comparative performances of ZSM‐5/HT‐hydr
for 5‐HMF yield were witnessed and over 90% recoveries were
obtained even after three cycles of catalyst regenerations.
However, a significant decrease in the activity of composites was
observed after more reaction runs, especially in ZSM‐5/HT‐dg. The
results on conversion and 5‐HMF yield of both catalysts after 5
cycles is included in Table 2. In Fig. 7b, it was observed that the
selectivity of ZSM‐5/HT‐hydr was sustained, while the selectivity of
ZSM‐5/HT‐dg decreased considerably. This result suggested that the
catalytic activity of ZSM‐5/HT‐dg could not be restored. The
reduction of catalytic activity of the composites was possibly due to
their decomposition during the reaction process.
The spent catalysts were characterized by various techniques.
As seen in the SEM images in Fig. 8, a significant change in the
surface morphologies of the composites and more aggregation of
particles, especially in ZSM‐5/HT‐dg, were obvious after five
catalytic runs. Also confirmed by the XRD measurements, the XRD
patterns in Fig. 9 showed a decrease in the degree of crystallinity of
the spent catalysts. The results also indicated that the layered
structure of HT in the composites was destroyed and transformed to
MgO by the reaction process. Additionally, when compared with
the pristine catalysts in Table 1, the total surface area, acidity, and
basicity of the used catalysts were reduced to 391 m2/g, 0.33
mmol/g, and 3.48 mmol/g for ZSM‐5/HT‐hydr and 264 m2/g, 0.27
mmol/g, and 4.85 mmol/g for ZSM‐5/HT‐dg, respectively. The result
isolation of 5‐HMF, but also minimized the side reactions involving
5‐HFM, thus increasing the selectivity toward 5‐HMF. Hence, our
approach with excellent bifunctional catalytic activity and
reusability of ZSM‐5/HT composites in the one‐pot biphasic system
signified the potential application in biomass conversion.
4.
Conclusions
We successfully designed acid‐base ZSM‐5/HT composites with
bifunctional catalytic activity by the hydrothermal and dry gel
methods. It was found that different preparation methods led to a
minimal difference in the surface properties. However, the
composite prepared by the hydrothermal method possessed a
higher ratio of acidity and basicity. Employed as a combined solid
acid‐base catalyst, the ZSM‐5/HT composites favoured a one‐pot
conversion of glucose to 5‐HMF in the biphasic H2O/THF/NaCl
solvent system. Under mild conditions, the composites improved
the conversion of glucose and enhanced the yield of 5‐HMF,
compared with the individual HT or ZSM‐5 catalyst. It was also
observed that ZSM‐5/HT composite prepared by
a facile
hydrothermal method had slightly better catalytic activity, but was
more selective, and more reusable. More importantly,
H2O/THF/NaCl solvent not only facilitated the isolation of 5‐HMF,
This journal is © The Royal Society of Chemistry 2019
New J. Chem., 2019, 00, 1‐8 | 7

New Journal of Chemistry
Page 8 of 9
PAPER
New Journal of Chemistry
1
2
3
4
5
6
7
but also minimized the side reactions involving 5‐HFM, thus 18 R.S. Thombal, V.H. Jadhav, Appl. Catal. A Gen., 2015, 499
,
View Article Online
DOI: 10.1039/C9NJ00462A
increasing the selectivity toward 5‐HMF. Hence, our approach with
213‐216.
excellent bifunctional catalytic activity and reusability of ZSM‐5/HT 19 B. Saha, M.M. Abu‐Omar, Green Chem., 2014, 16, 24‐38.
composites in the one‐pot biphasic system signified the potential 20 Y.J. Pagan‐Torres, T. Wang, J.M.R. Gallo, B.H. Shanks, J.A.
application in biomass conversion.
Dumesic, ACS Catal., 2012, 2, 930‐934.
21 Y. Yang, C. Hu, M.M. Abu‐Omar, Green Chem., 2012, 14, 509‐
513.
22 S. Dutta, S. De, M.I. Alam, M.M. Abu‐Omar, B. Saha, J. Catal.,
2012, 288, 8‐15.
8
9
Conflicts of interest
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
There are no conflicts to declare.
23 E. Nikolla, Y. Roman‐Leshkov, M. Moliner, M.E. Davis, ACS
Acknowledgements
Catal., 2011, 1, 408‐410.
24 L. Liao, N. Zhao, Z. Xia, Mater. Res. Bull., 2012, 47, 3897‐
3901.
We would like to thank the Nakhon Ratchasima Rajabhat University,
Thailand, for financial support and the Division of Chemical
Engineering, Graduate School of Engineering Science, Osaka
University, Japan, for chemicals and measurements. The TEM
measurement was carried out by using a facility in the Research
Center for Ultrahigh Voltage Electron Microscopy, Osaka University.
25 Y. Kuang, L. Zhao, S. Zhang, F. Zhang, M. Dong, S. Xu,
Materials, 2010, 3, 5220‐5235.
26 I. Jiménez‐Morales, A. Teckchandani‐Ortiz, J. Santamaría‐
González, P. Maireles‐Torres, A. Jiénez‐López, Appl. Catal. B,
2014, 144, 20‐28.
27 A. Takagaki, M. Takahashi, S. Nishimura, K. Ebitani, ACS
Catal., 2011, 1, 1562‐1565.
28 I. Jiménez‐Morales, M. Moreno‐Recio, J. Santamaría‐
González, P. Maireles‐Torres, A. Jiénez‐López, Appl. Catal. B,
2015, 164, 70‐76.
29 M. Moreno‐Recio, J. Santamaría‐González, P. Maireles‐
Torres, Chem. Eng. J., 2016, 303, 22‐30.
Notes and references
1
A.A. Rosatella, S.P. Simeonov, R.F.M. Frade, C.A.M. Afonso,
Green Chem., 2011, 13, 754‐793.
2
3
P. Gallezot, Chem. Soc. Rev., 2012, 41, 1538‐1558.
K. Shimizu, R. Uozumi, A. Satsuma, Catal. Commun., 2009, 10
(14),1849‐1853.
30 R. Otomo, T. Yokoi, J.N. Kondo, T. Tatsumi, Appl. Catal. A
Gen., 2014, 470, 318‐326.
31 X. Li, K. Peng, Q. Xia, X. Liu, Chem. Eng. J., 2018, 332, 528‐
536.
4
5
6
7
8
9
T.D. Swift, C. Bagia, V. Choudhary, G. Peklaris, V. Nikolakis,
D.G. Vlachos, ACS Catal., 4 (2014) 259‐267.
Y. Fengli, L. Qishun, B. Xuefang, D. Yuguang, Bioresour.
Technol., 2011, 102, 3424‐3429.
L. Atanda, S. Mukundan, A. Shrotri, Q. Ma, J. Beltramini,
Chem. Cat. Chem., 2015, 7, 781‐790.
D. Chen, F. Liang, D. Feng, M. Xian, H. Zhang, H. Liu, F. Du,
Chem. Eng. J., 2016, 300, 177‐184.
M. Moreno‐Recio, J. Santamaria‐Gonzalez, P. Maireles‐
Torres, Chem. Eng. J., 2016, 303, 22‐30.
J.C. Speck Jr., Adv. Carbohydrate Chem., 1958, 13, 63–103.
10 M. Ohara, A. Takagaki, S. Nishimura, K. Ebitani, Appl. Catal. A
Gen., 2010, 383, 149‐155.
11 C. Moreau, J. Lecomte, A. Roux, Catal. Commun., 2006,
941–944.
12 D.P. Debecker, E.M. Gaigneaux, G. Busca, Chem. Eur. J.,
2009, 15, 3920–3935.
13 A. Takagaki, M. Ohara, S. Nishimura, K. Ebitani, Chem.
Commun., 2009, 41, 6276‐6278.
14 T.S. Deng, X.J. Cui, Y.Q. Qi, Y.X. Wang, X.L. Hou, Y.L. Zhu,
Chem. Commun., 2012, 48, 5494‐5496.
15 Y. Zhang, J.J. Wang, J.W. Ren, X.H. Liu, X.C. Li, Y.J. Xia, G.Z. Lu,
7,
Y.Q. Wang, Catal. Sci. Technol., 2012,
16 I.J. Kuo, N. Suzuki, Y. Yamauchi, K.C.W. Wu, RSC Adv., 2013,
, 2028‐2034.
17 Y. Zhang, J. Pan, Y. Shen, W. Shi, C. Liu, L. Yu, ACS Sustainable
Chem. Eng., 2015, , 871‐879.
2, 2485‐2491.
3
3
8 | New J. Chem., 2019, 00, 1‐8
This journal is © The Royal Society of Chemistry 2019

Page 9 of 9
New Journal of Chemistry
1
2
3
4
View Article Online
DOI: 10.1039/C9NJ00462A
Table of Contents Entry
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Over 65% yield of 5-hydroxymethylfurfural from glucose was obtained under mild condition by using
ZSM-5/HT composite as acid/base bifunctional catalyst.