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Electronic Supplementary Material (ESI) for ChemComm.
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Supporting information
Selective Conversion of Coconut Oil to Fatty Alcohols in Methanol over
Hydrothermally Prepared Cu/SiO2 Catalyst without Extraneous
Hydrogen
Liubi Wu, Lulu Li, Bolong Li and Chen Zhao*
Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and
Molecular Engineering, East China Normal University, Shanghai 200062, China
Email: [email protected]
Experiment Section
Chemicals: Coconut oil was purchased from J&K Co. The analytical reagents of methyl laurate, methyl myristate,
methyl palmitate, and methyl stearate were obtained from J&K Co. The analytical pure chemicals of lauric acid, copper
(II) nitrate trihydrate, ammonium hydroxide solution, and ammonium chloride were provided by Sinopec Co., Ltd.
Nano-silicon dioxide was purchased from J&K Co. Air, hydrogen and nitrogen gases (99.999 vol. %) were supplied by
Shanghai Pujiang Specialty Gases Co., Ltd.
Synthesis of Cu/SiO2 by hydrothermal method (Cu/SiO2-HT): Firstly, Cu(NO3)2∙3H2O was dissolved in deionized
water, then adding a solution of NH4Cl and NH3∙H2O together with SiO2 into the copper solution with stirring at ambient
temperature for 0.5 h. Afterwards, the mixture was ultrasonic treated for another 0.5 h, and transferred into a Teflon
autoclave for 3 h at 120 °C. After cooling down to room temperature, the solid in the autoclave was filtered and washed
by deionized water until pH value attained 7. Finally, the precursor was dried at 60 °C overnight, and calcined in flowing
air at 450 °C for 4 h (heating rate: 2 °C∙min-1, flowing velocity: 100 mL∙min-1) and reduced in flowing hydrogen at 450
°C for 4 h (heating rate: 2 °C∙min-1, flowing velocity: 100 mL∙min-1).
Synthesis of Cu/SiO2 by impregnation method (Cu/SiO2-IM): A typical Cu/SiO2-IM was synthesized by
impregnation method. Firstly, Cu(NO3)2∙3H2O (3.80 g) was dissolved in distilled water (10 mL). Then the copper
precursor solutions was well-dropped onto SiO2 (2 g), which kept magnetic stirring at ambient temperature to dry out the
water. Finally, the solid was dried at 60 °C overnight, calcined in flowing air at 450 °C for 4 h (heating rate: 2 °C∙min-1 ,
flowing velocity:100 mL∙min-1) and reduced in flowing hydrogen at 450 °C for 4 h (heating rate: 2 °C∙min-1 , flowing
velocity: 100 mL∙min-1).
Synthesis of Cu/SiO2 by deposition-precipitation using urea as precipitant (Cu/SiO2-DP): A typical catalyst
Cu/SiO2-DP was synthesized as follows. An aqueous solution of Cu(NO3)2∙3H2O (0.10 M, 350 mL) was prepared and
divided into two parts. 200 mL was suspended with 2 g nano SiO2 (solution A) and heated to 70 °C. The rest (50 mL)
was dissolved with urea (6.3 g) (solution B), then drop-wise added into the former suspension. Next, the mixture was
heated up to 90 °C and kept reflux condensation for 10 h. After cooling down to ambient temperature, the catalyst
precursor was filtered and washed by distilled water several times. Finally, the solid was dried at 60 °C overnight,
calcined in flowing air at 450 °C for 4 h (heating rate: 2 °C∙min-1, flowing velocity:100 mL∙min-1) and reduced in
flowing hydrogen at 450 °C for 4 h (heating rate: 2 °C∙min-1, flowing velocity: 100 mL∙min-1).
Catalyst characterization
Cu contents were quantified by inductively coupled plasma atomic emission spectroscopy (ICP–AES) performed on a
Thermo IRIS Intrepid II XSP emission spectrometer after dissolving the catalyst in the HF solution. N2 adsorption
measurements were carried out at 77 K on a BEL-MAX gas/vapor adsorption instrument. The surface areas were
calculated by the Brunauer-Emmett-Teller (BET) method. Powder X-ray diffraction (XRD) patterns were detected to
confirm the structure and crystal size by Rigaku Ultima IV X-ray diffractometer utilizing Cu-Kα radiation (λ = 1.5405 Å)
operated at 35 kV and 25 mA. The IR spectra (IR) were collected by Nicolet Nexus 670 FT-IR spectrometer in
absorbance mode at a spectral resolution of 2 cm-1 using KBr technique. Hydrogen temperature programmed reduction
(TPR) was conducted by TP-5080 multi-purpose automatic adsorption instrument by at the ramp rate of 10 K min-1.
Scanning electron microscopy images (SEM) were performed on the Hitachi S-4800 microscope. To illuminate crystal
morphology and size, transmission electron microscopy (TEM) images were obtained by the FEI Tecnai G2 F30
microscope working at 300 kV. X-ray photoelectron spectroscopy (XPS) were performed with Al Kα (hν = 1486.6 eV)
radiation on a Thermo Scientific K-Alpha spectrometer. Charging effects were corrected by using the C 1s peak due to
adventitious carbon with EB fixed at 284.6 eV.
Catalytic tests
A typical test was carried out as follows: methyl laurate (1.0 g), methanol (40 mL) and Cu/SiO2-HT catalyst (0.1 g) were
added into a batch autoclave (70 mL). The reactor was then flushed with N2 (2 MPa) at ambient temperature for three
times to remove the residual air. After evacuating nitrogen, it was heated up to 240 °C. The reaction was conducted for 4
h at a stirring speed of 450 rpm. After cooling down to ambient temperature, liquid products were analyzed on a gas
chromatograph (GC) equipped with a mass spectrometer (GC-MS, Shimadzu QP-2010 Ultra) with a Rtx-5Sil MS
capillary column (30 m × 0.25 mm × 0.25 μm). Analysis for gaseous products was performed on a GC (Techcomp 7900)
equipped with thermal conductivity detector (TCD) and columns (TDX-01: 30 cm × 3 mm, TDX-01: 2 m × 3 mm), as
well as flame ionization detector (FID) and a HP-PLOT Q capillary column (50 m × 0.53 mm × 25 μm).
Test of the coconut oil components
Coconut oil (5.0 g), methanol (100 mL), and CaO (0.8 g) were added into a batch autoclave (Parr, 300 mL). The reactor
was then flushed with N2 at ambient temperature for three times. After evacuating nitrogen, it was heated up to 80 °C.
The reaction was conducted for 2 h at a stirring speed of 600 rpm. After cooling down to ambient temperature, liquid
products were analyzed by GC coupled with GC-MS.
Vads (cm3·g-1)
Vads (cm3·g-1)
400
350
300
250
200
150
100
50
0
Calcined Cu/SiO2-HT
Reduced Cu/SiO2-HT
(a)
0.0
350
300
250
200
150
100
50
0
0.2
0.4
P/P0
0.6
0.8
1.0
Calcined Cu/SiO2-DP
Reduced Cu/SiO2-DP
(b)
0.0
0.2
0.4
0.6
P/P0
0.8
1.0
Vads (cm3·g-1)
300
250
Calcined-Cu/SiO2-IM
200
Reduced-Cu/SiO2-IM
150
100
50
(c)
0
0.0
0.2
0.4
0.6
P/P0
0.8
1.0
Fig. S1 N2 adsorption and desorption isotherms of (a) Cu/SiO2-HT, (b) Cu/SiO2-DP and (c) Cu/SiO2-IM.
dV/dD (cm3·g-1·nm-1)
1.2
(a)
1.0
Calcined Cu/SiO2-HT
0.8
Reduced Cu/SiO2-HT
0.6
0.4
0.2
0.0
1
dV/dD (cm3·g-1·nm-1)
1.0
10
100
Pore Diameter (nm)
(b)
Calcined Cu/SiO2-DP
Reduced Cu/SiO2-DP
0.8
0.6
0.4
0.2
0.0
1
10
100
dV/dD (cm3·g-1·nm-1)
Pore Diameter (nm)
1.0
(c)
Calcined Cu/SiO2-IM
0.8
Reduced Cu/SiO2-IM
0.6
0.4
0.2
0.0
1
10
100
Pore Diameter (nm)
Fig. S2 BJH adsorption pore size distributions of (a) Cu/SiO2-HT, (b) Cu/SiO2-DP and (c) Cu/SiO2-IM.
(111)
Intensity (a.u.)
(a)
Cu
 CuO

Cu/SiO2-IM
(200)

reduced
(11-1) (111)
 
calcined
(110)

(11-3)
(31-1)
(20-2)  (020)
 

(202)
10
20
30
40
(111)

Cu/SiO2-DP
(220)
60
2 Theta (degree)
(b)
Intensity (a.u.)
50

70
Cu
CuO
(200)

reduced
(11-1)
calcined
 (111)

(110)

(20-2) (11-3)
(11-2)  (020)  (220)




(202) (31-1)
10
20
30
40
50
2 Theta (degree)
60
70
Fig. S3 XRD patterns of (a) Cu/SiO2-IM and (b) Cu/SiO2-DP after air-calcination and hydrogen-reduction.
H2 consumption (a.u.)
calcined sample
262 C
240 C
150
200
400
200
250
600
Temperature (C)
300
800
Fig. S4 H2-TPR profile of calcined Cu/SiO2-HT catalyst.
Absorbance (a.u.)
(a) Cu/SiO2- HT
CuSiO3·(n-x)H2O
OH
calcined
Absorbance (a.u.)
2500
2000 1500 1000
500
-1
Wavenumber (cm )
(b) Cu/SiO2- DPU
reduced
calcined
4000
Absorbance (a.u.)
SiO
reduced
(c)
4000
3000
2000
1000
Wavenumber (cm-1)
Cu/SiO2- IM
reduced
calcined
3000
2000
1000
Wavenumber (cm-1)
Fig. S5 IR spectra of different stateds of (a) Cu/SiO2-HT, (b) Cu/SiO2-IM and (c) Cu/SiO2-DP.
(a)
(b)
Fig. S6 SEM images of (a) calcined Cu/SiO2-HT and (b) reduced Cu/SiO2-HT catalysts.
(a)
(b)
(c)
D=16.1±6.0 nm
(d)
D=3.5±0.3 nm
Fig. S7 TEM images of (a) calcined Cu/SiO2-IM, (b) reduced Cu/SiO2-IM, (c) calcined Cu/SiO2-DP, and (d)
reduced Cu/SiO2-DP samples.
Fig. S8 The changes of Cu species on three Cu/SiO2 catalysts during the preparation processes synthesized by (a)
hydrothermal method, (b) impregnation method, and (c) deposition-precipitation method.
Weight (%)
100
95
90
85
80
75
30%
70
5%
65
0 100 200 300 400 500 600 700 800
Temperature (C)
Fig. S9 The TGA profile of hydrothermally prepared Cu/SiO2-HT (before calcination).
Pressure (MPa)
16
14
HT
IM
DP
12
10
0
50
100
150
200
250
Time (min.)
Fig. S10 Changed pressures were recorded in the autoclave with the varying time during the process of selective
hydrogenation at 240 ˚C using three Cu/SiO2 catalysts prepared by different methods. Reaction conditions: methyl
laurate (0.3 g), methanol (40 mL), Cu/SiO2 catalysts (0.2 g), 240 ˚C, 4 h, N2 (2 MPa), stirring at 400 rpm.
Pressure (MPa)
17 (a)
16
Cu/SiO2-HT
15
14
13
12
11
0
40
80
120 160 200 240
Time (min.)
Pressure (MPa)
11.0
(b)
10.5
10.0
9.5
9.0
0
11.0
Pressure (MPa)
Cu/SiO2-IM
40
80
120 160 200 240
Time (min.)
(c)
Cu/SiO2-DP
10.5
10.0
9.5
9.0
0
40
80
120 160 200 240
Time (min.)
Fig. S11 Comparison of the recorded pressure changes for methanol decomposition over (a) Cu/SiO2-HT, (b)
Cu/SiO2-IM and (c) Cu/SiO2-DP. Reaction conditions: methanol (40 mL), catalysts (0.2 g), 240 °C, N2 (2.0 MPa),
stirring at 400 rpm.
Pressure (MPa)
dried Cu/SiO2-HT
11.0
10.5
10.0
9.5
9.0
8.5
8.0
calcined Cu/SiO2-HT
0
50
100
150
Time (min.)
200
Fig. S12 The recorded pressure changes for methanol decomposition over Cu/SiO2 after (a) drying and (b)
calcination. Reaction conditions: methanol (40 mL), catalysts (0.2 g), 240 °C, N2 (2.0 MPa), stirring at 400 rpm.
(a) XRD pattern
Cu2O•SiO2
(b) XRD pattern
Cu0
Cu(1 1 1)
Cu(2 0 0)
20 30 40 50 60
2 Theta (degree)
70
(c) XRD pattern
Cu2O (2 0 0)
Cu2O (1 1 1)
Cu2O (2 2 0)
Cu2O (3 1 1)
10 20 30 40 50 60 70 80
2 Theta (degree)
10
20 30 40 50 60
2 Theta (degree)
(d) XPS spectra
Intensity (a.u.)
10
970
Cu
Cu2+  SiO32-
300
350
400
450
500
550
600
70
Cu 2p
Cu2O
960
950
940
930
Binding Energy (eV)
Fig. S13 The XRD patterns of (a) Cu/SiO2-HT, (b) washed Cu/SiO2-HT sample by 2 wt% HCl solution, (c) recalcinated Cu/SiO2-HT sample, and (d) the XPS spectra of Cu/SiO2-HT samples by different reduction
temperatures.
O
CH3OH
O
DMM
HCHO
Fig. S14 The formed dimethoxy methane and formaldehyde products from methanol decomposition detected by
GC-MS. Reaction conditions: methanol (40 mL), Cu/SiO2-HT (0.2 g), 240 ˚C, 4 h, N2 (2.0 MPa), stirring at 400
rpm.
OH
Intensity (a.u.)
OH
OH
OH
O
OH
OH
O
O
O
O
O
O
5
O
O
O
O
O
10
15
20
25
Retention time (min.)
30
Fig. S15 The product distributions for coconut oil conversion detected by GC-MS. Reaction conditions: coconut oil
(1.0 g), Cu/SiO2-HT (0.2 g), methanol (40 mL), 240 ˚C, 4 h, N2 (2.0 MPa), stirring at 400 rpm.
Alcohol Content (%)
60
51.1
50
40
30
18.9
20
10
0
0.3
C6
6.2 5.4
C8
8.6 9.5
C10 C12 C14 C16 C18
Fig. S16 The fatty acid compositions in coconut oil raw material detected by transesterification with methanol.
Reaction conditions: coconut oil (1.0 g), CaO (1 g), methanol (100 mL), 80 ˚C, 2 h.
Yield (%)
100
80
Fatty alcohols
FAMEs
15.4
15.9
16.5
17.6
84.6
84.1
83.5
82.4
Run 1
Run 2
Run 3 Run 4
60
40
20
0
Fig. S17 Recycling test of the hydrogenation of coconut oil over Cu/SiO2-HT (treated by sequential air-calcination
and hydrogen-reduction). Reaction conditions: coconut oil (1.0 g), Cu/SiO2-HT (0.2 g), methanol (40 mL), 240 ˚C,
4 h, N2 (2.0 MPa), stirring at 400 rpm.
(a)
Cu2O
(111) Cu
 (111)
Intensity (a.u.)
used

reduced
Cu2O Cu
(111)
(111) 

10
20 30 40 50
2 Theta (degree)
60
70
(b)
200
(c)
Weight (%)
150
100
50
0
0
200
400
600
800
Temperature (C)
Fig. S18 (a) XRD patterns, (b) TEM image and (c) TGA measurement of used Cu/SiO2-HT after reaction.

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