Catalytic conversion of fructose and sucrose to 5-hydroxymethylfurfural using simple ionic liquid/DMF binary reaction media

Article abstract of DOI:10.1016/j.catcom.2013.08.009

The production of 5-hydroxymethylfurfural (HMF) from carbohydrates has been reported intensively in recent years. HMF is believed to be a versatile platform chemical and the focus of synthesizing it has especially been on the development of efficient catalysts, such as Lewis and Br?nsted Acids. On the contrary, herein, we report a novel catalytic system that consists of 1-allyl-3-methylimidazolium chloride ([AMIM]Cl) and N,N-Dimethylformamide (DMF) without any additional metal salts or acids, which leads to reasonable HMF yields (84.9%) and selectivities. In addition, the degradation mechanism of fructose catalyzed by [AMIM]Cl is also proposed in this communication.

Full text of DOI:10.1016/j.catcom.2013.08.009

Catalytic Conversion of Fructose and Sucrose to 5-Hydroxymethylfurfural
Using Simple Ionic Liquid/DMF Binary Reaction Media
Jincai Shi, Yan Yang, Ningning Wang, Zhanxin Song, Haiyan Gao, Yongmei
Xia, Wei Li, Haijun Wang
PII:
DOI:
Reference:
S1566-7367(13)00318-X
doi: 10.1016/j.catcom.2013.08.009
CATCOM 3613
To appear in:
Catalysis Communications
Received date:
Revised date:
Accepted date:
3 July 2013
2 August 2013
15 August 2013
Please cite this article as: Jincai Shi, Yan Yang, Ningning Wang, Zhanxin Song, Haiyan
Gao, Yongmei Xia, Wei Li, Haijun Wang, Catalytic Conversion of Fructose and Sucrose
to 5-Hydroxymethylfurfural Using Simple Ionic Liquid/DMF Binary Reaction Media,
Catalysis Communications (2013), doi: 10.1016/j.catcom.2013.08.009
This is a PDF file of an unedited manuscript that has been accepted for publication.
As a service to our customers we are providing this early version of the manuscript.
The manuscript will undergo copyediting, typesetting, and review of the resulting proof
before it is published in its final form. Please note that during the production process
errors may be discovered which could affect the content, and all legal disclaimers that
apply to the journal pertain.

ACCEPTED MANUSCRIPT
Catalytic Conversion of Fructose and Sucrose to
5-Hydroxymethylfurfural Using Simple Ionic Liquid/DMF
Binary Reaction Media
Jincai Shia, Yan Yanga, Ningning Wanga, Zhanxin Songa, Haiyan Gaoa,
Yongmei Xiaa,b, Wei Lia, Haijun Wanga*
aSchool of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, China
bState Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122,China
1

ACCEPTED MANUSCRIPT
ABSTRACT
The production of 5-hydroxymethylfurfural (HMF) from carbohydrates has been
reported intensively in recent years. HMF is believed to be a versatile platform
chemical and the focus of synthesizing it has especially been on the development of
efficient catalysts, such as Lewis and Brønsted Acid. On the contrary, herein, we
report a novel catalytic system that consists of 1-allyl-3-methylimidazolium chloride
([AMIM]Cl) and N,N-Dimethylformamide (DMF) without any additional metal salts
or acids, which leads to reasonable HMF yields (84.9%) and selectivities. In addition,
the degradation mechanism of fructose catalyzed by [AMIM]Cl is also proposed in
this communication.
Keywords: 5-hydroxymethylfurfural, fructose, ionic liquid, N,N-Dimethylformamide,
system
2

ACCEPTED MANUSCRIPT
1. Introduction
Biomass is regarded as a potential abundant and renewable source to produce energy,
chemicals and materials[1, 2]. Carbohydrates represent 75% of the annual renewable
biomass. Fructose and sucrose are considered as superior carbohydrate compounds
from which various furan chemicals can be obtained[3]. For example,
5-Hydroxymethylfurfural (HMF), which is considered to be one of the top 12
bio-based building blocks listed by the U.S. Department of Energy[4].
The awareness that it will become necessary to produce HMF from sugars to take
place of fossil raw materials has led to an enormous increase in researching the
conversion process. It is significant to find a simple and efficient catalytic system to
convert monosaccharides and disaccharides into HMF. Therefore, various catalytic
systems including solid acids[5], mineral acids[6], alkaline[7] and acidic ionic
liquids[8] have been developed to achieve efficient transformation of sugars to HMF.
The dehydration of fructose and sucrose to HMF has been performed in many
different media, including (acidified) water[4, 9, 10], organic solvents[11],
multicomponent mixtures[12] and ionic liquids[13, 14]. In addition, metal chloride
salts are also applied to act as (co-)catalysts in the conversion, such as GeCl4[15] and
SnCl4[16]. Originally, acidic catalysts are generally regarded as the important and
essential compounds during the degradation of fructose, however, both Lewis Acid
and Brønsted Acid are found to have a lot of shortcomings: corrosive (HCl, H2SO4,
and CH3SO3H), toxic (SnCl4 and CrCl3), and difficult to recycle. Moreover, the
3

ACCEPTED MANUSCRIPT
post-processing is intractable due to the relative low selectivity of HMF, which is
unstable in the acidic[10] and high temperature[17] environment. For the aqueous
medium, because of the presence of water, levulinic acid (LA) and formic acid (FA)
are formed, which decreased the selectivity of HMF[4].
Thus, it is urgent to build a catalytic system to convert fructose and sucrose
efficiently that does not contain any metal salts or acids. Interestingly, some
comparative trials[18, 19] have recently revealed that the neutral ionic liquid
[BMIM]Cl had a small catalytic activity, even both the yield and selectivity are really
not satisfied. Moreover, as reported by Moreau et al., ~80% HMF yield was achieved
from fructose catalyzed by Amberlyst-15 in [BMIM]BF4 and [BMIM]PF6 with
DMSO as co-solvent within 24 h[20]. We herein systemically investigated a novel and
simple process for HMF formation from fructose and sucrose by using
[AMIM]Cl/DMF binary reaction system (Scheme 1 and Table S1). We hope this work
could provide a simple, efficient and environmentally friendly way for the production
of HMF from sugars.
Scheme 1. Fructose and Sucrose Conversion into HMF.
OH
HO
OH
HO
O
O
OH
OH
O
OH
OH
sucrose
[AMIM]Cl / DMF
HO
OH
OH
O
O
HO
OH
OH
[AMIM]Cl / DMF
-3H2O
O
HO
O
OH
OH
OH
OH
glucose
fructose
HMF
2. Experimental
4

ACCEPTED MANUSCRIPT
2.1 Preparation of [AMIM]Cl catalyst
N-methylimidazole and allyl chloride at a molar ratio 1:1.25 were added to a
round-bottomed flask fitted with a reflux condenser for 8 h at 55℃ with stirring. The
unreacted chemical reagents and other impurities, such as water, were removed by
vacuum distillation, and the obtained product [AMIM]Cl was further purified using
ethyl acetate and ether. After further evaporation of volatiles, the product was dried in
1
a vacuum oven at 60℃ for 2 days. H NMR (D2O): δ=3.92 (s, 3H; -CH3), 4.83 (d, J
6.0 Hz, 2H, -CH2), 5.43 (dd, J 29.6 13.7 Hz, 2H, -CH), 6.07 (dq, J 11.4 6.1 Hz, 1H,
13
-CH ), 7.48 (d, J 5.4 Hz, 2H; -CH2), 8.74 (s, 1H; -CH). C NMR (DMSO): δ=36. 26
(-CH3), 51.02 (-CH2), 120.49 (-CH2), 122.76 (-CH), 124.19 (-CH), 132.47 (-CH),
137.34 (-CH).
2.2 General procedure for synthesis of HMF from fructose
The reaction was carried out in a stainless steel autoclave with glass liner tube that
was heated in the oil-bath. A mixture of fructose (1.0 mmol) and [AMIM]Cl/DMF
media (5 ml) was placed in the tube, then heated and stirred at 100℃ for 45 min.
After reaction, the resultant mixture was cooled in the ice bath, then diluted with
deionized water and analyzed by HPLC.
3. Results and discusion
3.1 Effect of reaction time and temperature on dehydration
Temperature and time as the most critical parameters were initially investigated in
the systematic evaluation process. To confirm the best conditions, the degradation of
5

ACCEPTED MANUSCRIPT
fructose in the [AMIM]Cl/DMF media was studied. As is shown in Figure 1, both too
high temperature and too long time were not conducive to the stable of HMF due to
the side-reaction. The highest yield of HMF was 84.4% obtained at 100℃ for 45 min.
This yield was exceptional and comparable to the results obtained in many Lewis and
Brønsted Acid systems[11, 21]. It should be noted that the selectivity of HMF in the
present system was perfect (not shown here) and other by-products (furfural, LA and
formic acid) were found to be particularly low and was not considered.
Figure 1. HMF synthesis from fructose in [AMIM]Cl/DMF binary reaction system. Conditions:
Fructose (1 mmol), [AMIM]Cl (2 mL), DMF(3 mL).
3.2 Effect of volume ratio of [AMIM]Cl and DMF on dehydration
In order to confirm the roles of [AMIM]Cl and DMF played in the system, and
more importantly, to confirm the effect of volume ratio of [AMIM]Cl and DMF, we
then examined this condition. A series of volume ratios from 0 : 5 ([AMIM]Cl : DMF)
to 5 : 0 and reactions in pure DMF and pure water as blank reactions were screened
(Table 1 and S1). Both of the two solvents were not available for fructose degradation.
Different volume ratios of [AMIM]Cl and DMF had different effects on the yield of
6

ACCEPTED MANUSCRIPT
HMF, the results are presented in Table 1. It can be seen that HMF yield improved fast
when increasing the ratio of [AMIM]Cl, but it began to shrink when enhancing the
concentration of IL continually that exceeding 1/2. Meanwhile, a volume ratio of
[AMIM]Cl/DMF greater than 2 : 3 was required for efficient transformation of
fructose into HMF, and a volume ratio of 2.5 : 2.5 showed the best catalytic
performance (84.9%). Actually, from the cost point of view, the volume ratio of 2 : 3
was considered to be more appropriate due to the close yields of entry 3-5. In addition,
DMF revealed a significant function on reducing the viscosity of ionic liquid and
enhancing heat transfer effect, and HMF became more stable in the presence of DMF
in [AMIM]Cl.
Table 1. HMF yields according to volume ratio of [AMIM]Cl and DMFa.
t (min)
T (℃)
[AMIM]Cl
DMF
Conversion
HMF Yield
(%)
Entry
(mL)
(mL)
(%)
10
85
97
99
99
93
95
45
45
45
45
45
45
45
100
100
100
100
100
100
100
0
1
5
4
0.5
1
2
3
4
5
6
7
39.6
2
3
84.4
2.5
3
2.5
2
84.9
81.3
4
1
77.1
5
0
76.8
aConditions: Fructose (1 mmol), T=100℃, t=45 min.
3.3 Effect of impurities (water) in the system
Next, we found that in the presence of impurities in the system, particularly water,
the yield of HMF decreased sharply. Figure 2 shows the degradation of fructose to
HMF, the addition of water clearly lead to a serious decrease of HMF yield. From our
research, with the growing of deionized water added into the reaction system, the
HMF yield declined seriously. We speculated that water impaired the dissolution
7

ACCEPTED MANUSCRIPT
capacity of solvent and the stable balance of binary reaction media, causing the
declined catalytic activity of [AMIM]Cl. Moreover, with the presence of water, the
dehydration process of fructose was restrained seriously. To some extent, these
findings agree with our previous work[22] that the water in [BMIM]Cl had negative
effects on cellulose hydrolysis. In conclusion, strict purification procedures for
[AMIM]Cl/DMF system are required to ensure the dehydration of fructose effectively.
Figure 2. Effect of H2O added into system on the degradation of fructose. Conditions: Fructose (1
mmol), [AMIM]Cl (2 mL), DMF(3 mL), T=100℃, t=45 min.
3.4 HMF synthesis from various substrates
We then sought to explore the substrate scope in this simple catalytic system.
When disaccharides were converted, HMF yield was equal to mol(HMF) / mol(total
monomer). HMF was obtained in 40.3 % yield when sucrose was used as substrate (Table
2 and Figure S2). This result may be not comparable to the previous work by using
Lewis Acid catalysts (compared, for example, with 55.4% yield and ~98% conversion
were obtained at 120℃ for 30 min from sucrose in the presence of GeCl4[23]).
However, it is still acceptable due to the absence of metal salts and acids from the
8

ACCEPTED MANUSCRIPT
environmental viewpoint. When inulin was utilized as feedstock in the same reaction
conditions, HMF yield of 53.7% was obtained. When other sugars were used, HMF
yield was clearly lower and even cannot be detected. We reasoned that
[AMIM]Cl/DMF-based system can hardly promote aldose (glucose) into ketose
(fructose): the isomerization process. Sucrose is a disaccharide consisting of glucose
and fructose, so only the ketose product could convert into HMF. Interestingly, the
yield of HMF from sucrose was exactly a half of the yield that obtained from fructose,
which confirmed our inference further.
Table 2. HMF synthesis from sugars in [AMIM]Cl/DMF systema.
Substrate
Sucrose
t (min)
T (℃)
HMF Yieldc (%)
Entry
45
60
90
45
60
90
45
45
45
60
100
100
100
100
100
100
100
100
100
100
36.5
40.3
33.1
0.5
7
8
9
Glucose
10
11
12
13
14
15
16
0.8
0.9
Maltose
Lactose
Galactose
Inulin
NDb
NDb
NDb
53.7
aConditions: Substrate (1mmol), [AMIM]Cl (2 mL), DMF (3mL). ND =
b
Not Detected. cHMF yield was equal to mol(HMF) / mol(total monomer)
3.5 Recycling and reutilization of reaction media
.
Reutilization of the catalyst is highly preferable in terms of green chemistry. Thus,
the recycling experiments of [AMIM]Cl/DMF system were carried out using the
synthesis of HMF from fructose as a model reaction. After reaction, the reaction
mixture was first distilled under reduced pressure. Pure DMF was collected and the
remaining mixture was extracted with ethyl acetate after water was added, similar to
9

ACCEPTED MANUSCRIPT
other procedures in the literature[8]. The obtained mixture after extraction was heated
at 80℃ for 12 h in a vacuum oven to remove water and residual ethyl acetate.
[AMIM]Cl was then used directly in the next run by adding the distilled DMF and an
equal amount of fructose. As is shown in Figure 3(a), in a test of five cycles, the
catalyst could be reused without any significant loss of catalytic activity (84.8% yield
in the first cycle versus 80% in the fourth cycle). In order to further verify the stability
of [AMIM]Cl, a FT-IR characterization experiment was also carried out. As can be
seen in Figure 3(b), [AMIM]Cl remained stable after five cycles. Comparing the
reused [AMIM]Cl with the fresh [AMIM]Cl, no distinct difference was observed.
(a)
(b)
Figure 3. (a) Recycle experiments of [AMIM]Cl/DMF system. Balck bar: Fructose conversion,
red bar: HMF yield. (b) FT-IR characterization of the reused [AMIM]Cl with the fresh [AMIM]Cl.
3.6 Mechanism of the fructose dehydration catalyzed by [AMIM]Cl
Much effort has been devoted to reveal the mechanism of the conversion of
fructose into HMF catalyzed by Lewis and Brønsted Acids. However, the catalytic
system that without H+ or Mn+ (metal ions) was remained not fully studied. As is
10

ACCEPTED MANUSCRIPT
shown in Figure 4, chloride ion played an important role in the conversion process.
Firstly, a molecule of water removed when compound IM1 formed via the attachment
of Cl- to the two OH groups on C1 and C2. Then an enediol intermediate (IM2) is
formed and rapidly isomerizes into its isomers aldehyde (IM3). Next, with the
formation of another molecule of water which released from IM3, the product IM4 is
formed. Then following the similar route above, the third water molecule is removed.
Finally, both IL and H2O are dissociated from IM5 to give the target product.
It is suggested that in salt solutions with small, strong polarizing cations and large
polarizable anions, intensive interactions with OH occur[24]. In comparison with
[BMIM]Cl, we speculate that the cation [AMIM]+ is conducive to the attack on OH
groups due to the smaller ion size and a double bond in the cation of [AMIM]Cl.
Moreover, the less electronic chemical structure caused by allyl group also enhances
the interaction between cations in [AMIM]Cl and hydroxyl. Further investigations on
the capture of the intermediates are underway.
H
OH
O
OH
H
OHC
OH
OH
OHC
OH
OH
HO
Cl
O
HO
O
O
H
H
H
H
-H2O
H
HO
H
H
HO
OH
Cl
OH
-H2O
H
OH
OH
H
Cl
N
N
CH3
N
Cl
N
N
N
CH3
C3H5
N
CH3
N
CH3
C3H5
C3H5
C3H5
IM 3
IM 2
IM 1
IM 4
O
O
OHC
OHC
OH
OH
O
H
-H2O
-IL
OH
O
H
Cl
N
OH
H
H
N
CH3
H
Cl
C3H5
N
CH3
N
C3H5
HMF
IM 6
IM 5
Figure 4. Possible mechanism for the dehydration of fructose. –C3H5 = Allyl.
11

ACCEPTED MANUSCRIPT
4. Conclusions
In summary, we demonstrated that [AMIM]Cl/DMF binary reaction media was an
excellent combination for the conversion of fructose and sucrose to HMF. High HMF
yield was obtained in this simple and efficient catalytic/solvent system. [AMIM]Cl
played an important role in the fructose conversion process and the possible
mechanism for the dehydration of fructose was proposed. We believe that, the
efficient, cheaper and reusable catalytic system has great potential for application in
future.
Acknowledgment
The authors are grateful to the Fundamental Research Funds for the Central
Universities (JUSRP211A12) and Natural Science Foundation of Jiangsu Province
(SBK201222312) for financial support.
12

ACCEPTED MANUSCRIPT
References
[1] M. Mascal, E.B. Nikitin, Angew. Chem. Int. Ed. Engl., 47 (2008) 7924-7926.
[2] Z. Zhang, Z.K. Zhao, Bioresour. Technol., 101 (2010) 1111-1114.
[3] X. Tong, Y. Ma, Y. Li, Carbohydr. Res., 345 (2010) 1698-1701.
[4] A. Ranoux, K. Djanashvili, I.W.C.E. Arends, U. Hanefeld, ACS Cata., 3 (2013)
760-763.
[5] R. Kourieh, V. Rakic, S. Bennici, A. Auroux, Cata. Commun., 30 (2013) 5-13.
[6] S.J. Dee, A.T. Bell, ChemSusChem, 4 (2011) 1166-1173.
[7] Y.-S. Qu, Y.-L. Song, C.-P. Huang, J. Zhang, B.-H. Chen, Ind. Eng. Chem. Res. ,
51 (2012) 13008-13013.
[8] X. Tong, Y. Li, ChemSusChem, 3 (2010) 350-355.
[9] B.F.M. Kuster, Carbohydr. Res. , 54 (1977) 177-183.
[10] V. Choudhary, S.H. Mushrif, C. Ho, A. Anderko, V. Nikolakis, N.S. Marinkovic,
A.I. Frenkel, S.I. Sandler, D.G. Vlachos, J. Am. Chem. Soc., 135 (2013) 3997-4006.
[11] B.R. Caes, R.T. Raines, ChemSusChem, 4 (2011) 353-356.
2 . Ni olla, . Rom n-Leshkov, M. Moliner, M.E. Davis, ACS Cata., 1 (2011)
408-410.
[13] E.A. Khokhlova, V.V. Kachala, V.P. Ananikov, ChemSusChem, 5 (2012)
783-789.
[14] A.H. Jadhav, H. Kim, I.T. Hwang, Cata. Commun., 21 (2012) 96-103.
[15] Z. Zhang, B. Liu, Z. Zhao, Carbohydr. Poly., 88 (2012) 891-895.
13

ACCEPTED MANUSCRIPT
[16] G. Tian, X. Tong, Y. Cheng, S. Xue, Carbohydr. Res., 370 (2013) 33-37.
[17] A.A. Rosatella, S.P. Simeonov, R.F.M. Frade, C.A.M. Afonso, Green Chem., 13
(2011) 754-793.
[18] C. Sievers, I. Musin, T. Marzialetti, M.B. Valenzuela Olarte, P.K. Agrawal, C.W.
Jones, ChemSusChem, 2 (2009) 665-671.
[19] C.Y. Shi, Y.L. Zhao, J.Y. Xin, J.Q. Wang, X.M. Lu, X.P. Zhang, S.J. Zhang,
Chem. Commun., 48 (2012) 4103–4105.
[20] C. Lansalot-Matras, C. Moreau, Cata. Commun., 4 (2003) 517-520.
[21] Y.Y. Lee, K.C. Wu, Phys. Chem. Chem. Phys., 14 (2012) 13914-13917.
[22] J. Shi, H. Gao, Y. Xia, W. Li, H. Wang, C. Zheng, RSC Adv., 3 (2013)
7782-7790.
[23] Z. Zhang, Q. Wang, H. Xie, W. Liu, Z.K. Zhao, ChemSusChem, 4 (2011)
131-138.
[24] H. Zhang, J. Wu, J. Zhang, J. He, Macromolecules, 38 (2005) 8272-8277.
14

ACCEPTED MANUSCRIPT
Graphical Abstract
TOC
OH
HO
OH
O
HO
O
OH
OH
O
Without Adding any
Metal Salts or Acids
OH
OH
sucrose
[AMIM]Cl / DMF
HO
OH
OH
O
O
HO
OH
OH
[AMIM]Cl / DMF
-3H2O
O
HO
O
OH
OH
OH
OH
glucose
fructose
HMF
15

ACCEPTED MANUSCRIPT
Highlights
 Simple and efficient ionic liquid/DMF binary reaction media is used.
 A high yield (84%) of HMF is obtained from fructose.
 Investigation of recovery method for HMF from media.
 [AMIM]Cl played an important role in the fructose conversion mechanism.
16