Synthesis of hydroxymethylfurfural from sucrose using Br?nsted-Lewis acidic ionic liquid

Article abstract of DOI:10.4314/bcse.v30i2.12

The synthesis of 5-hydroxymethylfurfural (HMF) from sucrose was investigated in the presence of the Br?nsted-Lewis acidic ionic liquids (ILs). It was concluded that IL 1-(3-sulfonic acid)-propyl-3-methylimidazole chlorochrominate [HO₃S-(CH₂)₃-mim]Cl-CrCl₃ (molar fraction of CrCl₃ x = 0.55) had a good catalytic performance with 78.8% yield of HMF. The acid type of IL played a significant role in the reaction. Lewis acid site acted more effectively than its Br?nsted counterpart and a synergetic effect of Br?nsted and Lewis acid sites enhanced the IL catalytic performance. The reusability of IL was good.

Full text of DOI:10.4314/bcse.v30i2.12

Bull. Chem. Soc. Ethiop. 2016, 30(2), 283-288.
Printed in Ethiopia
DOI: http://dx.doi.org/10.4314/bcse.v30i2.12
ISSN 1011-3924
 2016 Chemical Society of Ethiopia
SYNTHESIS OF HYDROXYMETHYLFURFURAL FROM SUCROSE USING
BRÖNSTED-LEWIS ACIDIC IONIC LIQUID
Lin Yao, Shiwei Liu*, Lu Li, Shitao Yu*, Fusheng Liu and Zhanqian Song
College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao
266042, China
(Received March 11, 2014; revised May 20, 2016)
ABSTRACT. The synthesis of 5-hydroxymethylfurfural (HMF) from sucrose was investigated in the presence
of the Brönsted-Lewis acidic ionic liquids (ILs). It was concluded that IL 1-(3-sulfonic acid)-propyl-3-
methylimidazole chlorochrominate [HO3S-(CH2)3-mim]Cl-CrCl3 (molar fraction of CrCl3 x = 0.55) had a good
catalytic performance with 78.8% yield of HMF. The acid type of IL played a significant role in the reaction.
Lewis acid site acted more effectively than its Brönsted counterpart and a synergetic effect of Brönsted and Lewis
acid sites enhanced the IL catalytic performance. The reusability of IL was good.
KEY WORDS: Acidic ionic liquid, Sucrose, 5-Hydroxymethylfurfural, Catalysis
INTRODUCTION
5-Hydroxymethylfurfural (HMF) is one key furan derivative readily accessible from renewable
resources like carbohydrates, in particular through acid–catalyzed reaction of biomass sugar
such as fructose, sucrose and glucose. HMF is a particularly suitable starting material for the
preparation of further furan monomers required for the preparation of non-petroleum-derived
polymeric materials, such as polyesters, polyamides and polyurethanes [1, 2]. Usually the
traditional inorganic acids, such as H2SO4 [3], were used as catalysts in these reaction. The
drawbacks of these processes include low selectivity of the desired HMF, serious corrosion of
equipments, complicated separation procedures, environmental problems, and not recyclable of
catalysts. Solid catalysts, such as the aluminophosphates [4], transition metal phosphate [5] and
sulfonic acid functionalized mesoporous silica [6], were also reported as catalysts in these
reactions. They also have shortcomings, such as restricted accessibility to the matrix bound
catalytic sites, high molecular weight/active site ratios, and rapid deactivation from coking.
Therefore, it is necessary to explore a new approach for the synthesis of HMF from sucrose.
HMF is actually formed from the reaction of sucrose through a series of intermediates [7]. The
process is composed of several elementary reactions, such as protonation, dehydration, and
deprotonation (Scheme 1). Generally, Brönsted acid is active to protonation and dehydration,
and Lewis acid facilitates the deprotonation [8].
As a kind of environmental-friendly catalysts, Brönsted or Lewis acidic ionic liquids (ILs)
get attentions of researchers [9], and many organic reactions, such as transesterification [10],
alkylation [11], polymerization [12] and carbonylation [13] were reported with excellent
selectivity, and the used ILs were of outstanding recyclability. Studies involving the utilization
of ILs as reaction media or as catalysts for the reaction of biomass sugar to HMF have also been
reported. For example, Moreau et al., demonstrated that neutral ILs, such as [BMIm]PF6 and
[BMIm]BF4, acted as a suitable reaction medium for the dehydration of fructose to HMF in the
presence of the acidic catalyst Amberlyst-15 [14]. The Brönsted acidic IL, 1-H-3-methyl
imidazolium chloride was also used as both solvent and catalyst for the reactions of fructose and
sucrose to produce HMF [15]. Recently, metal chlorides in the neutral IL [EMIm]Cl was found
to be an effective catalyst for converting biomass sugar to HMF. The above results suggested
__________
*Corresponding author. E-mail: liushiweiqust@126.com

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Lin Yao et al.
that ILs as solvents or catalysts played a positive role in the development of an effective process
for the reaction of sugars to HMF [8]. In our laboratory, some Brönsted-Lewis acidic ILs were
synthesized, characterized and used in the polymerization [16, 17]. The results indicated that the
Brönsted-Lewis acidic ILs were both Brönsted and Lewis acidic and had the better catalytic
performance for the polymerization than the traditional catalysts. Due to the presence of
Brönsted and Lewis acid sites, these ILs can selectively catalyze different reaction mechanisms
to enhance the reaction conversion and selectivity. As an extension of our ongoing studies of
these acidic ILs, we reported herein their applications as catalysts for the reaction of sucrose to
produce HMF, together with an effort to characterize ILs using UV-visible spectroscopy. The
characterization results revealed that the type of IL acidity played a significant role in the
efficiency of the reaction.
CH2OH
H
H
H
O
H
O
HOH2C
O
H
OH
H
HO
CH2OH
HO
OH
H
H
OH
H+
OH
OH
HOH2C
CH2OH
HOH2C
CHO
+
OH OH
O
OH
OH
OH
CHOH
via(i)
-H2O
CH
OH
via(ii)
HO
CH
O
CH2OH
HOH2C
HOH2C
CHO
OH
OH
HO
OH
OH
OH
OH
OH
HO
-H2O
CH2OH
-H2O
O
CHOH
HOH2C
CH CH
-H2O
CHO
HOH2C
HO
O
HO
-H2O
CHO
O
-H2O
HOH2C
HO
CHO
HO
O
Scheme 1. Reaction of sucrose to HMF.
EXPERIMENTAL
Materials and apparatus
Sucrose (99.8 wt%, Sigma Aldrich), 1-methylimidazole (99.8 wt%, Sigma Aldrich), 1,3-
propane sultone (1,2-oxathiolane-2,2-dioxide, 99.7 wt%, Albright and Wilson), and other
chemicals (analytic purity) were commercially available and used without further purification.
IR spectra were recorded by a Nicolet 510P FT-IR spectrometer in the range of 4500–400
cm–1. NMR spectra were taken by a Bruker AV500 Fourier-Transform spectrometer with
Bull. Chem. Soc. Ethiop. 2016, 30(2)

Synthesis of hydroxymethylfurfural from sucrose using Brönsted-Lewis acidic ionic liquid 285
reference to SiMe4, using solvent D2O containing 5 wt% of the sample. Quantitative analysis of
the product sample was recorded by HP-LC, which was a Shimadzu LC-6A pump and a
refractive index RID-6A detector. The used column was a BIORAD HPX-87H (300 mm×7.8
mm). Deionized water was the eluent (0.6 mL/min), and sorbose was the internal standard.
Preparation of ILs
Using the procedure in the literature [16] 1,3-propane sultone was reacted with N-
methylimidazole to give 3-(methylimidazole-N-yl)–propane-1-sultonate as zwitterion. Then it
was reacted with an equal mole of hydrochloric acid to give (3-sulfonic acid)-propyl-
methylimidazole chloride [HO3S-(CH2)3-mim]Cl as a white viscous liquid at room temperature.
The Brönsted-Lewis acidic ILs were prepared by the reaction of [HO3S-(CH2)3-mim]Cl with
metal chlorides, including FeCl3, ZnCl2 and CrCl3. The Lewis acidity of IL depended on the
metal chloride mass. When the molar fraction of metal chloride was less than 0.5, IL only had
Brönsted acidity and no Lewis acidity, and above this value, the obtained IL was Brönsted-
Lewis acidic. The reaction formula for the synthesis of IL [HO3S-(CH2)3-mim]Cl-CrCl3 (x =
0.67) was showed in Scheme 2. The acidities of ILs were characterized and determined on the
basis of the Hammett acidity function. As shown in the following equation, the Hammett acidity
function can be expressed as:
H0 = pK (I)aq +log([I] / [IH]+ )
where pK(I)aq is the pKa value of the indicator p-nitroaniline referred to as the aqueous solution,
[IH]+ and [I] are respectively the molar concentrations of the protonated and unprotonated forms
of the indicator, which is usually determined by UV–visible spectroscopy [20]. [HO3S-(CH2)3-
mim]Cl-CrCl3 (x = 0.67): IR (KBr disc, cm–1): ν 3380, 2987, 1627, 1483, 1147, 1044, 738, 606.
1H NMR (500 MHz, D2O, ppm): δ 1.95 (t, 2H), 2.83 (t, 2H), 3.15 (m, 2H), 3.64 (s, 3H), 6.86 (t,
1H), 7.01 (t, 1H), 7.38 (s, 1H). 13C NMR (255 MHz, D2O, ppm): δ 134.70, 122.33, 121.15,
47.24, 46.93, 34.25, 24.73.
Scheme 2. Synthesis of IL [HO3S-(CH2)3-mim]Cl-CrCl3 (x = 0.67).
Catalytic properties test
In a typical experiment, 2.0 g sucrose, 20 mL dimethyl sulfoxide and 1.6 g IL were added into a
50 mL stainless steel autoclave and reacted for 30 min at 200 oC. After the reaction, the reaction
mixture was cooled, and the upper layer, containing the product, solvent dimethyl sulfoxide and
unreacted reactant, was separated from the IL layer at the bottom of the flask simply by
decantation. The IL layer was reused directly in the cycle experiments. All samples of the upper
layer were analyzed by HP-LC. Analyses were performed using a Shimadzu LC-6A pump and a
refractive index RID-6A detector. The used column was a BIORAD HPX-87H (300 mm × 7.8
mm). Deionized water was the eluent (0.6 mL/min), and sorbose was the internal standard. HMF
yield was directly given by the system of LC chemstation according to the area of each
chromatograph peak.
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Lin Yao et al.
RESULTS AND DISCUSSION
Effects of different catalysts on the reaction
As can be seen from Table 1, compared with the traditional catalyst H2SO4 (30 wt%), all
Brönsted-Lewis acidic ILs exhibited better catalytic performance. Especially, IL [HO3S-(CH2)3-
mim]Cl-CrCl3 (x = 0.55) exhibited good catalytic property with more than 78% yield of the
product HMF. When Lewis acidic IL [C4mim]Cl-CrCl2 (x = 0.55) and Brönsted acidic IL
[HO3S-(CH2)3-min]Cl were used as catalysts, the yields of HMF were only 37.1% and 48.7%,
respectively. When the fractions of metal chloride (x) were less than 0.5, the obtained ILs were
only Brönsted acidic, and their Hammett acidity functions (H0) were near to those of Brönsted-
Lewis acidic ILs which the fractions of metal chloride (x) were more than 0.5, but the results of
the reaction used them as catalysts were not satisfied. It was indicated that the type of acidity
played a significant role in the efficiency of the reaction reaction. The good catalytic
performance of Brönsted-Lewis acidic IL was due to its types of Brönsted and Lewis acidities
and a synergetic effect. The Brönsted and Lewis acid sites can selectively catalyze the
elementary reactions, such as protonation, dehydration, and deprotonation, on the reaction
processes of the sucrose to HMF through a series of cyclic furan intermediates, and the
synergetic effect of both acidic sites enhanced the catalytic performance of IL (Scheme 1.). The
metal chlorides had a decisive influence on the catalytic performances of ILs, and IL [HO3S-
(CH2)3-mim]Cl-CrCl3 (x = 0.55) showed the best catalytic performance. These results can be
explained by the different role on the stability to the product HMF, and CrCl3 plays a good role
in stabilizing HMF, which can hinder the decomposition of HMF to form levulinic acid and
formic acid. Among the chlorochrominate ILs, the HMF yield was increased with the molar
fraction of CrCl3 (x). When x value was 0.55, the reaction of sucrose was effectively catalyzed.
This can be explained by that, when the molar fraction of metal chloride (x) was more than 0.5,
IL was Brönsted and Lewis acidic, and by increasing the x value, the Lewis acidity was
increased [18], which can increase the catalytic activity of IL. But further increased x value, the
result was not good. It was indicated that too high a Lewis acid strength was adjective for the
reaction.
Table 1. Effects of catalysts on the reaction resultsa.
Entry
1
Catalyst
Blank
H0
–
Conversion /%
–
Yield /%
0
2
3
4
5
6
7
8
9
10
11
12
13
14
[C4mim]Cl
[C4mim]Cl-CrCl3 (x = 0.55)
30 wt% H2SO4
–
–
95.0
92.9
96.5
92.6
95.8
96.0
94.9
94.9
95.1
95.1
96.4
97.7
14.6
37.1
46.6
48.7
70.2
77.3
73.6
60.7
65.9
66.1
74.8
78.7
76.7
–1.53
2.91
3.21
2.81
2.62
2.84
2.70
2.64
2.75
2.56
2.46
[HO3S-(CH2)3-mim]Cl
[HO3S-(CH2)3-mim]Cl-ZnCl2 (x = 0.33)
[HO3S-(CH2)3-mim]Cl-ZnCl2 (x = 0.55)
[HO3S-(CH2)3-mim]Cl-ZnCl2 (x = 0.60)
[HO3S-(CH2)3-mim]Cl-FeCl3 (x = 0.33)
[HO3S-(CH2)3-mim]Cl-FeCl3 (x = 0.55)
[HO3S-(CH2)3-mim]Cl-FeCl3 (x = 0.60)
[HO3S-(CH2)3-mim]Cl-CrCl3 (x = 0.33)
[HO3S-(CH2)3-mim]Cl-CrCl3 (x = 0.55)
[HO3S-(CH2)3-mim]Cl-CrCl3 (x = 0.60)
95.7
aSucrose 2.0 g, dimethyl sulfoxide 20 mL, catalyst 2.0 g, T = 200 oC, t = 30 min.
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Synthesis of hydroxymethylfurfural from sucrose using Brönsted-Lewis acidic ionic liquid 287
Effects of reaction conditions on the reaction
The effects of reaction conditions were showed in Table 2. The IL dosage was very important
for the reaction. With increasing of IL [HO3S-(CH2)3-mim]Cl-CrCl3 (x = 0.55) dosage from 1.6
g to 2.8 g, the yield of HMF increased from 72.2% to 78.8%. When increasing of solvent
dimethyl sulfoxide dosage from 10 mL to 30 mL, the yield of HMF increased from 45.3% to
77.9%. This result was due to the difference in dissolubility of sucrose and HMF in the reaction
mixture. The reaction temperature and time were also important for the reaction. At 180 oC, the
o
HMF yield was only 65.4%. But when the temperature reached 200 C, the HMF yield was
reached to 78.7%. However, the yield of product was not increased further after that. This may
be because too high reaction temperature facilitated the decomposition of the product HMF.
With increasing reaction time from 10 min to 30 min, the yield of product HMF increased from
65.7% to 77.8%. However, the HMF yield decreased to 72.1% at 40 min. It can be seen that
both too high a reaction temperature and too long a reaction time were unfavorable to the yield
of HMF.
Table 2. Effects of reaction conditions on the reaction results.
Entry
1
2
3
4
5
6
7
8
IL /g
1.6
2.0
2.4
2.8
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
Solvent /mL
T / oC
200
200
200
200
200
200
180
220
240
220
220
220
t /min
30
30
30
30
30
30
30
30
30
10
20
40
Conversion /%
92.3
Yield /%
72.2
78.7
78.6
78.8
45.3
77.9
65.4
77.8
65.0
65.7
67.9
72.1
20
20
20
20
10
30
20
20
20
20
20
20
97.7
97.4
98.8
95.0
93.2
94.6
99.0
100
9
10
11
12
91.6
94.6
100
Reusability of catalyst
The reusability of [HO3S-(CH2)3-mim]Cl-CrCl3 (x = 0.55) was investigated, and the results were
given in Table 3. The results showed that HMF yield was almost unchanged after [HO3S-
(CH2)3-mim]Cl-CrCl3 (x = 0.55) was used repeatedly five times. It was indicated that the
Brönsted-Lewis acidic IL was of excellent reusability. The good reusability may be explained
by the following two points. Firstly, in the structure of IL, the alkyl sulfonic acid group is
covalently tethered in IL cation, and the anions [CrCl4]－ and [Cr2Cl7]－ of IL are inert and stable
in water and Brönsted acid. Therefore the acidity of IL is not easily lost. Secondly, the use of
CrCl3 increases the density of the IL, which gives an easier separation of IL from the reaction
mixture, and then IL is not easily lost in the separation process. Therefore, its activity was
stable.
Table 3. Reusability of the IL catalyst.
Cycle
Conversion /%
97.7
Yield /%
78.7
78.6
78.2
78.5
1
2
3
4
5
97.9
96.8
97.5
97.8
78.4
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Lin Yao et al.
CONCLUSION
The synthesis of 5-hydroxymethylfurfural (HMF) from sucrose was investigated using the
Brönsted-Lewis acidic ILs as catalysts. IL (3-sulfonic acid)-propyl-methylimidazole
chloroimidazole [HO3S-(CH2)3-mim]Cl-CrCl3 (x = 0.55) had the good catalytic property and the
yield of product was 78.7%. The type of acidity of ILs played a significant role in the efficiency
of the reaction. The Brönsted-Lewis acidic sites of IL could selectively catalyze the protonation,
dehydration, and deprotonation dehydrogenation in the reaction, and a synergetic effect of
Brönsted and Lewis acid sites enhanced the catalytic performance of the IL.
ACKNOWLEDGMENTS
This work was financially supported by the Natural Science Foundation of Shandong
(ZR2010BQ018) and the Postdoctoral Science Foundation of Shandong (201003051). The
authors are grateful for the financial support.
REFERENCES
1. Chermahini, A.N.; Shahangi, F.; Dabbagh, H.A.; Saraji, M. RSC Advances 2016, 6, 33804.
2. Corma, A.; Iborra, S.; Velty, A. Chem. Rev. 2003, 107, 2411.
3. Nikolla, E.; Roman–Leshkov, Y.; Moliner, M.; Davis, M.E. ACS Catalysis 2011, 1, 408.
4. Gemechu, D.; Wondimagenge, M.; Yonas, C.; Isabel D. Bull. Chem. Soc. Ethiop. 2014, 28,
45.
5. Jadhav, A.H.; Kim, H.; Hwang, I.T. Biores. Technol. 2013, 132, 342.
6. Huang, H.; Denard, C.A.; Alamillo, R.; Crisci, A.J.; Miao, Y.R.; Dumesic, J.A.; Scott, S.L.;
Zhao, H.M. ACS Catalysis 2014, 4, 2165.
7. Antal, M. J.; Mok, W. S. L.; Richards, G. N. Carbohyd. Res. 1990, 199, 91.
8. Zhao, H. B.; Holladay, J. E.; Brown, H.; Zhang, Z. C. Science 2007, 316,1597.
9. Heravi, M. M.; Ansari, P.; Saeedi, M.; Karimi, N.; Tavakoli–Hosseini, N. Bull. Chem. Soc.
Ethiop. 2011, 25, 315.
10. Liu, S.W.; Wang, Z.P.; Yu, S.T.; Xie, C.X. Bull. Chem. Soc. Ethiop. 2013, 27, 289.
11. Kondamudi, K.; Elavarasan, P.; Dyson, P.J. J. Mol. Catal. A: Chem. 2010, 321, 34.
12. Steinkoenig, J.; Bloesser, F.R.; Huber, B.; Welle, A.; Trouillet, V.; Weidner, S.M.; Barner,
L.; Roesky, P.W.; Yuan, J.Y.; Goldmann, A.S.; Barner–Kowollik, C. Polym. Chem. 2016, 7,
451.
13. Lapidus, A.L.; Eliseev, O.L. Solid Fuel Chem. 2010, 44, 197.
14. Lansalot–Matras, C.; Moreau, C. Catal. Commun. 2003, 4, 517.
15. Moreau, C.; Finiels, A.; Vanoye, L. J. Mol. Catal. A: Chem. 2006, 253, 165.
16. Liu, S.W.; Xie, C.X.; Yu, S.T.; Liu, F.S. Catal. Commun. 2008, 9, 2030.
17. Liu, S.W.; Zhou, H.X.; Yu, S.T.; Xie, C.X.; Liu, F.S.; Song, Z.Q. Chem. Eng. J. 2011, 174,
396.
18. Coffie, S.; Hogg, J.M.; Cailler, L.; Ferrer–Ugalde, A.; Murphy, R.W.; Holbrey, J.D.;
Coleman, F.; Swadźba-Kwaśny, M. Angew. Chem. Int. Ed. 2015, 54, 149703.
19. Wasserscheid, P.; Keim, W. Angew. Chem. Int. Ed. 2000, 39, 3772.
20. Xing, H.; Wang, T.; Zhou, Z.; Dai, Y. J. Mol. Catal. A: Chem. 2007, 264, 53.
Bull. Chem. Soc. Ethiop. 2016, 30(2)