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: czhao@chem.ecnu.edu.cn

Electronic Supplementary Material (ESI) for ChemComm.This journal is © The Royal Society of Chemistry 2017

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.

0.0 0.2 0.4 0.6 0.8 1.00

50100150200250300350

V ads (

cm3 ·g

-1)

P/P0

Calcined Cu/SiO2-DP Reduced Cu/SiO2-DP

0.0 0.2 0.4 0.6 0.8 1.00

50100150200250300

V ads (

cm3 ·g

-1)

P/P0

Calcined-Cu/SiO2-IM Reduced-Cu/SiO2-IM

0.0 0.2 0.4 0.6 0.8 1.00

50100150200250300350400

P/P0

V ads (

cm3 ·g

-1)

Calcined Cu/SiO2-HT Reduced Cu/SiO2-HT

(b)

(c)

(a)

Fig. S1 N2 adsorption and desorption isotherms of (a) Cu/SiO2-HT, (b) Cu/SiO2-DP and (c) Cu/SiO2-IM.

1 10 100

0.0

0.2

0.4

0.6

0.8

1.0

dV/d

D (c

m3 ·g

-1·n

m-1)

Pore Diameter (nm)

Calcined Cu/SiO2-IM Reduced Cu/SiO2-IM

1 10 100

0.0

0.2

0.4

0.6

0.8

1.0

dV/d

D (c

m3 ·g

-1·n

m-1)

Pore Diameter (nm)

Calcined Cu/SiO2-DP Reduced Cu/SiO2-DP

(b)

(c)

1 10 1000.00.20.40.60.81.01.2

Calcined Cu/SiO2-HT Reduced Cu/SiO2-HT

Pore Diameter (nm)

dV/d

D (c

m3 ·g

-1·n

m-1) (a)

Fig. S2 BJH adsorption pore size distributions of (a) Cu/SiO2-HT, (b) Cu/SiO2-DP and (c) Cu/SiO2-IM.

10 20 30 40 50 60 70

In

tens

ity (a

.u.)

2 Theta (degree)

(31-1)

Cu CuOCu/SiO2-IM

reduced

calcined

(111)

(200)

(110)

(11-1) (111)

(20-2) (020)

(202)

(11-3)

(220)

10 20 30 40 50 60 70

CuO

Cu

2 Theta (degree)

Inte

nsity

(a.u

.)

(11-1)

(111)

(200)

(111)

(11-2)(20-2)

(020)

(202)

(11-3)

(31-1)

(220)calcined

reduced

(110)

Cu/SiO2-DP

(a)

(b)

Fig. S3 XRD patterns of (a) Cu/SiO2-IM and (b) Cu/SiO2-DP after air-calcination and hydrogen-reduction.

200 400 600 800

150 200 250 300

262 C

240 C

H

2 con

sum

ptio

n (a

.u.)

Temperature (C)

calcined sample

Fig. S4 H2-TPR profile of calcined Cu/SiO2-HT catalyst.

Fig. S5 IR spectra of different stateds of (a) Cu/SiO2-HT, (b) Cu/SiO2-IM and (c) Cu/SiO2-DP.

2500 2000 1500 1000 500

Cu/SiO2- HT

SiO

A

bsor

banc

e (a

.u.)

Wavenumber (cm-1)

calcined

reduced

OH

CuSiO3·(n-x)H2O

4000 3000 2000 1000

Cu/SiO2- IM

reduced

calcined

Wavenumber (cm-1)

Abs

orba

nce

(a.u

.)

4000 3000 2000 1000

Cu/SiO2- DPU

reduced

calcined

Wavenumber (cm-1)

Abs

orba

nce

(a.u

.)

(a)

(c)

(b)

(a) (b)

Fig. S6 SEM images of (a) calcined Cu/SiO2-HT and (b) reduced Cu/SiO2-HT catalysts.

D=16.1±6.0 nm D=3.5±0.3 nm(b)

(a) (c)

(d)

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.

0 100 200 300 400 500 600 700 800

65707580859095

100

Wei

ght (

%)

Temperature (C)

30%

5%

Fig. S9 The TGA profile of hydrothermally prepared Cu/SiO2-HT (before calcination).

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.

0 50 100 150 200 250

10

12

14

16

HT IM DP

Time (min.)

Pr

essu

re (M

Pa)

0 40 80 120 160 200 2409.0

9.5

10.0

10.5

11.0

Pres

sure

(MPa

)

Time (min.)

Cu/SiO2-IM

0 40 80 120 160 200 2409.0

9.5

10.0

10.5

11.0Cu/SiO2-DP

Pres

sure

(MPa

)

Time (min.)

(c)

0 40 80 120 160 200 24011

12

13

14

15

16

17

Cu/SiO2-HT

Pr

essu

re (M

Pa)

Time (min.)

(a)

(b)

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.

0 50 100 150 200

8.08.59.09.5

10.010.511.0

Time (min.)

Pr

essu

re (M

Pa)

dried Cu/SiO2-HT calcined Cu/SiO2-HT

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.

10 20 30 40 50 60 70

Cu0Cu2O•SiO2

2 Theta (degree)

XRD pattern

10 20 30 40 50 60 70

XRD pattern

Cu(2 0 0)

2 Theta (degree)

Cu(1 1 1)

10 20 30 40 50 60 70 80

XRD pattern

Cu2O (3 1 1)Cu2O (2 2 0)

Cu2O (2 0 0)

2 Theta (degree)

Cu2O (1 1 1)

970 960 950 940 930

Cu

Inte

nsity

(a.u

.)

Binding Energy (eV)

300 350 400 450 500 550 600

XPS spectra Cu 2p

Cu2OCu2+ SiO32-

(a) (b)

(c) (d)

Fig. S13 The XRD patterns of (a) Cu/SiO2-HT, (b) washed Cu/SiO2-HT sample by 2 wt% HCl solution, (c) re-calcinated Cu/SiO2-HT sample, and (d) the XPS spectra of Cu/SiO2-HT samples by different reduction temperatures.

DMM

O O

HCHO

CH3OH

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.

5 10 15 20 25 30

In

tens

ity (a

.u.)

Retention time (min.)

OH

OO

OH

OO

OO

OH

OO

OH

OO

OH

OO

OH

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.

0.36.2 5.4

51.1

18.9

8.6 9.5

0

10

20

30

40

50

60

C8

Alc

ohol

Con

tent

(%)

C6 C12C10 C14 C18C16

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.

0

20

40

60

80

100

Yiel

d (%

)

Fatty alcohols FAMEs

15.4

84.6

15.9

84.1

16.5

83.5

17.6

82.4

Run 1 Run 2 Run 3 Run 4

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.

10 20 30 40 50 60 70

In

tens

ity (a

.u.)

2 Theta (degree)

Cu(111)

Cu2O(111)reduced

Cu(111)

Cu2O(111)used

(a)

(b)

0 200 400 600 8000

50

100

150

200

Wei

ght (

%)

Temperature (C)

(c)

Fig. S18 (a) XRD patterns, (b) TEM image and (c) TGA measurement of used Cu/SiO2-HT after reaction.