Supplementary Material (ESI) for Chemical Communications
This journal is © The Royal Society of Chemistry 2009
Supporting Information for
Integrating Enzymatic and Acid Catalysis to Convert Glucose into
5-Hydroxymethylfurfural
Renliang Huang
Wei Qi*
Rongxin Su
Zhimin He
State Key Laboratory of Chemical Engineering, School of Chemical Engineering and Technology,
Tianjin University, Tianjin 300072, China, Fax: (+86)22-2740-7599
E-mail: [email protected]
1. Experimental Section
1.1. Conversion of glucose into 5-hydroxymethylfurfural (HMF)
In a typical experiment, an aqueous solution (approximately pH 7.7, 20 mL) containing
glucose (1.00 g), sodium tetraborate (for example, 1.06 g) and MgSO4·7H2O (50 mg, used to
activate the glucose isomerase) was prepared in an Erlenmeyer flask. The resulting mixture
was placed in a shaking water bath at 150 rpm and 70 oC, and then immobilized glucose
isomerase (Sweetzyme IT, 0.50 g) was added to catalyze the isomerization reaction. After the
reaction, glucose isomerase was recycled by vacuum filtration. The supernatant was collected
and mixed with hydrochloric acid (37 wt%, 0.60 mL), NaCl (2.00 g, used to improve the
partitioning of HMF into the organic phase) and 1-butanol (30 mL) in a reaction vessel (100
mL). The two-phase reactor was transferred into an oil bath at 190 oC (placed on a magnetic
stirrer) to perform the dehydration reaction. The reaction was then stopped by cooling the
reactor in a refrigerator (-20 oC). The HMF product after phase separation was analyzed and
quantified by HPLC.
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Supplementary Material (ESI) for Chemical Communications
This journal is © The Royal Society of Chemistry 2009
1.2. Analytical methods
Sugars disappearance and the reaction products were analyzed and quantified by HPLC
using Bio-Rad Aminex HPX-87H column (5 mM H2SO4, 0.6 mL/min, 65 °C). Further
analysis was carried out by on-line liquid chromatography–tandem mass spectrometry
(LC–MS/MS) system equipped Surveyor PDA detector and a LCQ Advantage MAX ion trap
mass spectrometer (Thermo Finnigan, San Jose, CA). Samples were loaded onto Agilent
Zorbax SB-C18 reverse phase column (methanol/water gradient elution, 0.8 mL/min) for
separation. Full scans were performed between m/z 100 and 800. A full-scan MS spectrum
was acquired followed by tandem mass spectra using collision-induced dissociation (CID) of
the three most intense precursor ions present in the MS scan.
11
B NMR spectra were recorded at 96.28 MHz with boric acid (50 mg/mL) as the
external reference on Varian Mercury-300BB NMR spectrometer.
13
C NMR measurements
were performed at 75.45 MHz using a Varian Mercury-300BB NMR spectrometer. In each
case, the temperature was about 25 oC. The samples containing borate were prepared by
dissolution of sugar (100 mg) and sodium tetraborate (105.8 mg) in D2O (2.00 mL).
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Supplementary Material (ESI) for Chemical Communications
This journal is © The Royal Society of Chemistry 2009
2. Supporting Figures
b
100
100
90
Conversion and selectivity (%)
Conversion and selectivity (%)
a
80
70
60
50
40
Conversion
Selectivity
30
20
10
0
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
90
80
70
60
50
40
Conversion
Selectivity
30
20
10
0
1.0
0
2
4
Borate ratio to glucose (mol/mol,%)
6
8
10
12
14
16
18
Reaction time (h)
Fig. S1. Glucose conversion and fructose selectivity in the isomerization reaction. (Conversion =
weight of glucose reacted / weight of glucose initial; selectivity = weight of fructose produced /
weight of glucose reacted)
100
HMF
Absorbance (%)
80
60
40
20
0
0
2
4
6
8
10
12
14
16
18
20
22
24
Retention Time (min)
Fig. S2. HPLC analysis spectrum of liquid products. Operating conditions: Zorbax SB-C18
reverse phase column, methanol/water gradient elution (0~6 min: 7:3 water/methanol; 7~25min:
3:7 water/methanol), 0.8 mL/min, 285 nm.
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Supplementary Material (ESI) for Chemical Communications
This journal is © The Royal Society of Chemistry 2009
127.1
a) MS
80
60
40
b) MS/MS
109.0
100
Relative Abundance (%)
Relative Abundance (%)
100
Precursor ion:127.1
80
60
40
20
0
60
80
100
120
140
160
180
200
220
240
m/z
109.0
20
0
100
200
300
400
500
600
700
800
m/z
Fig. S3. a) Mass spectrum of the selected peak (assigned to HMF) in Fig.S1; b) Tandem mass
spectrum of singly charged ion m/z 127.1. (HMF showing an intense [M-H]+ signal at m/z 127.1;
Loss of 18 amu [OH-H] from the molecular ion gives the peak at m/z=109.0.)
a) Aqueous phase
b) Organic phase
3
HMF
6
HMF
1
FA LA
2
8
3 FA LA
6
1
4 5
12
16
20
24
28
8
4 5
12
16
20
24
28
Retention time (min)
Retention time (min)
Fig. S4. HPLC analysis spectra of liquid products. Operating conditions: Bio-Rad Aminex
HPX-87H column, 5 mM H2SO4, 0.6 mL/min, 65 °C. Peaks assignment: (1) glucose; (2) fructose;
(3) sodium tetraborate; (4) formic acid (FA); (5) levulinic acid (LA); (6) 5-hydroxymethylfurfural.
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Supplementary Material (ESI) for Chemical Communications
This journal is © The Royal Society of Chemistry 2009
monoester
diester
a)
Glucose-borate
10
0
-10
b)
-20
-30
-40
-50
monoester
diester
20
Fructose-borate
20
10
0
-10
-20
-30
-40
-50
PPM
Fig. S5. 11B NMR spectra of sugar–borate complexes. The spectra were recorded at 25 oC with
boric acid as the external reference. Peaks assignment: a) glucose-borate (monoester, 12.98 ppm;
diester, 8.45 ppm); b) fructose-borate (monoester, 13.44 ppm; diester, 9.21 ppm).
a)
Glucose
110
100
90
80
70
60
50
90
80
70
60
50
Glucose-borate
110
100
PPM
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Supplementary Material (ESI) for Chemical Communications
This journal is © The Royal Society of Chemistry 2009
b)
Fructose
110
100
90
80
70
60
50
90
80
70
60
50
Fructose-borate
110
100
PPM
Fig. S6. 13C NMR spectra of sugar–borate complexes. a) glucose and its complexes; b) fructose
and its complexes. The peaks assignment was summarized in Table S1.
3. Supporting Tables
Table S1 13C Chemical shift of sugars and of their B-L and B-L2 borate esters at pH 7.7 a
13
Ligand – L
D-glucose
C Chemical shift (ppm)
C-1
C-2
C-3
C-4
C-5
C-6
L
92.2
71.6
72.9
69.8
71.6
60.7
B-L+B-L2b
102.9
78.1
76.9
68.9
75.6
63.8
L
96.0
74.3
75.9
69.8
76.1
60.9
B L+B L2
103.2
82.5
77.2
68.9
77.8
63.8
L
62.8
101.6
75.5
74.6
80.8
62.5
B-L+B-L2
64.2
111.3
83.4
77.4
85.2
62.2
L
64.0
98.2
67.7
69.8
69.3
63.5
B-L+B-L2
66.5
103.6
68.8
69.6
70.9
63.4
α-glucopyranose
β-glucopyranose
-
D-fructose
β-fructofuranose
β-fructopyranose
-
a
Assignment of the free sugars (L) and borate eaters (B-L and B-L2) according to refs.1~2.
b
B-L and B-L2 represent the 1:1 (1 molecule boron : 1 molecule sugar) and 1:2 species of borate
esters, respectively.
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Supplementary Material (ESI) for Chemical Communications
This journal is © The Royal Society of Chemistry 2009
References
[1]
R. Van den Berg, J. A. Peters, H. Van Bekkum, Carbohydr. Res. 1994, 253, 1.
[2]
S. Chapelle, J. F. Verchere, Tetrahedron 1988, 44, 4469.
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