Transesterification of glycerol trioleate catalyzed by basic ionic liquids immobilized on magnetic nanoparticles: Influence of pore diffusion effect

Article abstract of DOI:10.1016/j.apcata.2012.12.029

Supported ionic liquids have become a hotspot in heterogeneous catalysis. 1-Allyl-dodecylimidazolium hydroxide ([ADIm][OH]) basic ionic liquids immobilized on magnetic mesoporous SiO₂/CoFe₂O₄ nanoparticles (SCF) and magnetic CoFe₂O₄ nanoparticles (CF) were prepared and characterized via FTIR, XRD, TEM, TG-DTA, VSM, elemental analysis and N₂ adsorption-desorption measurements. Catalytic performance of both supported ionic liquids catalysts (SILCs) was evaluated through transesterification of glycerol trioleate. The SCF carrier consisted of mesoporous silica matrix and uniformly dispersed CoFe₂O₄ nanoparticles, while CF carriers were nanosized CoFe₂O₄ particles with an average size of 15 nm. All of the carriers and the supported catalysts showed excellent paramagnetism. The two SILCs showed excellent catalytic activities higher than NaOH. Furthermore, the structure of the carriers had important influence on the catalytic performance of SILCs. Compared with the two SILCs, [ADIm][OH]/SCF presented a lower catalytic activity at the beginning of the reaction but higher catalytic activity when reaction time was long enough than [ADIm][OH]/CF due to the pore diffusion effect.

Full text of DOI:10.1016/j.apcata.2012.12.029

Applied Catalysis A: General 453 (2013) 327–333
Contents lists available at SciVerse ScienceDirect
Applied Catalysis A: General
journal homepage: www.elsevier.com/locate/apcata
Transesterification of glycerol trioleate catalyzed by basic ionic liquids
immobilized on magnetic nanoparticles: Influence of pore diffusion
effect
Yaping Zhang, Qingze Jiao, Bin Zhen, Qin Wu, Hansheng Li∗
School of Chemical Engineering and the Environment, Beijing Institute of Technology, Beijing 100081, China
a r t i c l e i n f o
a b s t r a c t
Article history:
Supported ionic liquids have become a hotspot in heterogeneous catalysis. 1-Allyl-dodecylimidazolium
hydroxide ([ADIm][OH]) basic ionic liquids immobilized on magnetic mesoporous SiO2/CoFe2O4 nanopar-
ticles (SCF) and magnetic CoFe2O4 nanoparticles (CF) were prepared and characterized via FTIR, XRD,
TEM, TG–DTA, VSM, elemental analysis and N2 adsorption–desorption measurements. Catalytic per-
formance of both supported ionic liquids catalysts (SILCs) was evaluated through transesterification of
glycerol trioleate. The SCF carrier consisted of mesoporous silica matrix and uniformly dispersed CoFe2O4
nanoparticles, while CF carriers were nanosized CoFe2O4 particles with an average size of 15 nm. All of the
carriers and the supported catalysts showed excellent paramagnetism. The two SILCs showed excellent
catalytic activities higher than NaOH. Furthermore, the structure of the carriers had important influence
on the catalytic performance of SILCs. Compared with the two SILCs, [ADIm][OH]/SCF presented a lower
catalytic activity at the beginning of the reaction but higher catalytic activity when reaction time was
long enough than [ADIm][OH]/CF due to the pore diffusion effect.
Received 8 November 2012
Received in revised form
20 December 2012
Accepted 21 December 2012
Available online xxx
Keywords:
Magnetism
Mesoporous silica
Nanoparticle
Supported ionic liquid catalyst
Transesterification
© 2012 Elsevier B.V. All rights reserved.
1. Introduction
lead to low grafting amount of ionic liquids, high mass-transfer
resistance and poor catalytic activities. To elevate the grafting
Ionic liquids show extremely low volatility, high thermal sta-
bility, wide liquid phase temperature range, nonflammability, high
chemical stability, high ionic conductivity, and wide electrochem-
ical window [1], and play important roles in catalysis both as
catalysts and carriers of catalysts [2,3]. However, the large-scale
application of ionic liquids is still far from realization because of
their high cost, large consumption and difficult recovery [4]. Sup-
ported ionic liquid catalysts (SILCs) with a catalytic amount of ionic
liquids immobilized on solid carriers combine the advantages of
both heterogeneous catalysts in terms of their easy separation and
recovery and homogeneous catalysts in that the ionic liquid films on
the carrier surfaces provide a homogeneous environment for cat-
alytic reactions [5,6]. The preparation and application of SILCs have
become an intensively studied hotspot in heterogeneous cataly-
sis.
amount of ionic liquids, mesoporous materials like MCM-41 and
SBA-15 were chosen as support materials because of their high
specific area, large pore volume and narrow pore distribution. The
SILCs have been used in transesterification [11], oxidative carbony-
lation [12], alkylation [13] and Knoevenagel condensation [14].
Nevertheless, mass-transfer resistance also exists in the pores of
the materials and affects catalytic activity badly. At the same time,
ultrafine powders and nanoparticles have been introduced as car-
riers to solve the mass-transfer difficulty. However, the ultrascaled
and nanosized structures often cause the difficulty in separation
of catalysts from reaction system via routine methods such as free
sedimentation, centrifugation and filtration.
Magnetic materials can be easily collected due to their magnetic
response in an external magnetic field and put forward a solution to
this problem. Magnetic nanoparticles have been used to immobi-
lize ionic liquids and the supported catalysts have been used in the
hydrogenation of alkynes [15], Suzuki coupling reactions [16], CO2
cycloaddition reactions [17], esterifications [18], three-component
condensations [19] and Knoevenagel condensation [20,21]. All of
these catalysts showed good catalytic performance, especially in
separation and recovery. Magnetic mesoporous nanoparticles were
also used as support materials. Acid ionic liquid supported on mag-
netic mesoporous silica particles exploited by our group displayed
Conventional materials, such as silica [7,8] and resin [9,10], are
usually used as carriers due to their easy availability and low cost.
However, the wide-range pore distribution, irregular pore shape,
low pore volume and low specific surface area of these carriers often
∗
Corresponding author. Tel.: +86 010 68918979.
E-mail address: hanshengli@bit.edu.cn (H. Li).
0926-860X/$ – see front matter © 2012 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.apcata.2012.12.029

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Y. Zhang et al. / Applied Catalysis A: General 453 (2013) 327–333
good catalytic performance in esterifications, but the catalytic
activity was obviously affected by the molecular size of reactants
[2].
Based on the research above, it is necessary to investigate the
influence of pore diffusion effect and surface immobilization of
carriers on the catalytic performance of catalysts. In this work, mag-
netic mesoporous SiO2/CoFe2O4 nanoparticles (SCF) and magnetic
CoFe2O4 nanoparticles (CF) were used as carriers to immobilize
basic ionic liquid, and the consecutive transesterification of glycerol
trioleate containing three long straight-chain groups was chosen as
a model reaction to study the relationship between the structure
and catalytic activities of the two catalysts.
2. Experimental
2.1. Materials
Analytically pure CoCl2·6H2O, Fe(NO3)3·9H2O, methylamine
solution, tetraethoxysilane (TEOS), n-hexane, n-hexanol, triton X-
100 and chemically pure glycerol trioleate were purchased from
Sinopharm Chemical Reagent Co. Ltd. (Beijing, China) and used as
received. 3-Mercaptopropyl trimethoxysilane (MPTMS, 97%) and 1-
allylimidazole was purchased from Acros Organics (Geel, Belgium)
and used as received. Analytically pure methanol, acetonitrile, n-
dodecyl bromide and azodiisobutyronitrile (AIBN) were purchased
from Beijing Chemical Works (Beijing, China), and acetonitrile and
AIBN were purified before use.
Scheme 1. Preparation of [ADIm][OH]/SCF and [ADIm][OH]/CF.
were achieved after washing with water and ethanol and drying
at 60 ◦C [23] (Scheme 1).
2.2. Preparation of catalysts
2.3. Sample characterization
2.2.1. Preparation of carriers
Fourier transform infrared (FTIR) spectrometry analysis was car-
ried out on a NICOLET iS10 Fourier transform infrared spectrometer
(Thermo, America) in a frequency range of 400–4000 cm−1 with a
resolution of 4 cm−1, a scanning number of 16 and KBr as a ref-
erence. The thermal analysis was performed on a TG–DTA 6200
(SII Nano Technology Inc., Japan), with a heating rate of 10 K min−1
from room temperature to 700 ◦C. X-ray diffraction pattern (XRD)
was collected on a Ultima IV X ray diffractometer (Rigaku, Japan)
with Cu K␣ radiation. Transmission electron microscopy (TEM)
observation was performed on a JEM-2100 transmission elec-
tron microscope (JEOL, Japan). Nitrogen adsorption–desorption
isotherms were determined at 77 K using an autosorb iQ porosime-
ter. Prior to measurement, the samples were degassed at 200 ◦C for
2 h. Specific surface areas and pore distributions were calculated
using the Brunauer–Emmett–Teller (BET) and nonlocal density
functional theory (NLDFT) methods, respectively. The magnetism
analysis was performed on a JLDJ 9600 vibrating sample magne-
tometer (LD, America). The particles size analysis was performed on
Malvern Zetasizer Nano ZS90 (Malvern Instruments Ltd., England).
Magnetic SCF carrier was prepared by
in reverse microemulsion combined with solvent-thermal tech-
nique according to a previous literature [22]. A microemulsion
a sol–gel process
with CoFe2O4 precursors was synthesized using
a double-
microemulsion method. Next, a TEOS solution of n-hexane was
added into the microemulsion. As the reaction ongoing, the TEOS
molecules diffused from the oil phase into the water phase,
hydrolyzed and became sols. The obtained sols were transferred
into a high-pressure reactor to form the SiO2 gel coating on the
CoFe2O4 precursors. Finally, the precipitates were washed with
ethanol, dried and calcined to achieve SCF microparticles.
CF carrier was obtained by alkali-treating SCF particles in NaOH
solution at 60 ◦C for 24 h after centrifugation and washing with de-
ionized water.
2.2.2. Modification of carriers
3-Mercaptopropyltrimethoxysilane was added into the aqueous
solution containing SCF (or CF) particles and treated in a thermal
kettle at 110 ◦C for 24 h. After washing with acetone and drying, the
black particles were obtained. The modified carriers were noted as
MSCF and MCF, respectively.
2.4. Transesterification procedure
2.2.3. Preparation of supported ionic liquids
The catalytic activities of the catalysts were evaluated using the
transesterification of glycerol trioleate (TG) with methanol. 16.10 g
of methanol, a 1/30 equimolar amount of TG and the catalyst that
contained 0.0278 mmol OH− were added into a 40 mL rotating
autoclave and reacted at 170 ◦C for 6 h. A high performance liq-
uid chromatography (HPLC, Techcomp LC2000) equipped with an
ultraviolet photometric detector was used for analyzing the com-
ponents. A Kromasil 100-5C18 column (4.6 mm × 5 ␮m × 250 mm)
was used and the mobile phase was a mixture of acetone and ace-
tonitrile in the volumetric ratio of 1:1 at a flow rate of 1.0 ml/min.
The column temperature was 25 ◦C and the detection wavelength
was 210 nm. The samples were diluted with HPLC grade acetone.
The yield of ME (YME) and the selectivities of products (Si, i = 1 (DG),
Supported ionic liquids catalysts were prepared through the free
radical reaction between allyl groups of ionic liquids and sulfhydryl
groups of MSCF and MCF. Firstly, 1-allylimidazole and n-dodecyl
bromide were added into flask and reacted at 60 ◦C for 24 h, after
washing with diethyl ether and dried in vacuum oven, the yel-
low [ADIm][Br] was synthesized. Next, [ADIm][Br] and MSCF (or
MCF) were added into hydrothermal reactor with acetonitrile as
solvent, and initiated by AIBN at 100 ◦C for 24 h, after washing
with methanol, the black [ADIm][Br]/SCF (or [ADIm][Br]/CF) were
prepared. Finally, [ADIm][Br]/SCF (or [ADIm][Br]/CF), NaOH and
dichloromethane were added into flask at room temperature and
reacted for 24 h. The black [ADIm][OH]/SCF (or [ADIm][OH]/CF)

Y. Zhang et al. / Applied Catalysis A: General 453 (2013) 327–333
329
Fig. 1. XRD patterns and magnetism (a) and FTIR spectra (b) of SCF and CF.
2 (MG), and 3 (ME)) were calculated according to the equations list
as follows:
ni
nME
i × ni
i=1j · ni
Ci
=
× 100%, YME
=
× 100%, Si
=
× 100%
ꢀ
ꢀ
3
3
3 × nTG,0
nTG
+
i=1ni
In the equations, nTG,0 is the molar amount of TG before reaction;
ni is the molar amount of i; j is the number of ester group in i.
3. Results and discussion
3.1. Structure and magnetism of SCF and CF
The crystal structure and chemical composition of SCF and CF
were analyzed by XRD and FTIR. In the XRD patterns of SCF and
CF shown in Fig. 1, the peaks at 35.44◦, 43.06◦, 56.97◦ and 62.59◦,
indexed to the 3 1 1, 4 0 0, 5 1 1 and 4 4 0 planes of cobalt ferrite
phase, respectively, prove the formation of cobalt ferrite (JCPDS
PDF#22-1086). Magnetic hysteresis loops of SCF and CF reveal
that the carriers own excellent paramagnetism, which is owed
to the existence of cobalt ferrite. The saturation magnetization
(Ms) and remnant magnetization (Mr) of SCF are 7.9105 emu/g and
0.0072 emu/g, and the corresponding data for CF are 26.8596 emu/g
and 0.0951 emu/g, respectively. The high magnetic responsivity
and paramagnetism are favorable for magnetic separation. In the
FTIR spectrum of SCF displayed in Fig. 1, the absorption peaks at
587 cm−1, 806 cm−1, 1063 cm−1 and 3435 cm−1 are assigned to
the M O vibration (M = Fe or Co), the antisymmetric and sym-
metric O Si O stretching vibrations, and the superficial hydroxyl
vibration, respectively [24]. These peaks can still be seen in the
FTIR spectrum of CF, but the intensity of peaks at 806 cm−1 and
1063 cm−1 decreased obviously. This means that a little of leftover
silica existed in CF. Based on the findings above, SCF and CF are
composed of cobalt ferrite and silica.
Fig. 2. TEM image and pore distributions of SCF.
proportion of 5–10 nm pores increases obviously and the average
pore size of SiO2 obtained from SCF diminishes slightly, which fur-
ther prove the size of removed cobalt ferrite particles.
In summary, SCF consist of mesoporous silica matrix and uni-
formly dispersed cobalt ferrite nanoparticles, while CF are cobalt
ferrite nanoparticles with a little of silica on the surface.
To further investigate the relative distribution of cobalt fer-
rite particles and silica, SCF was characterized through TEM and
N2 adsorption–desorption. As the TEM image of SCF shown in
Fig. 2, the nanoparticles of cobalt ferrite, which are dark particles,
do not aggregate like conventional magnets, instead dispersing in
the nanosized silica matrix. The N2 adsorption–desorption of SCF
reveals that many mesopores exist in SCF and the pore width in the
samples generally ranges from 5 to 20 nm. TEM and laser particle
size analysis were carried out to characterize the structure and size
of CF. The histogram of CF particles displayed in Fig. 3 shows that
the size of CF has a narrow distribution with an average value of
15 nm. It is concluded that the CF are nanosized and monodisperse.
To further approve these results, SCF were treated in HCl aque-
ous solution to remove cobalt ferrite, and the remaining SiO2 was
obtained after washing with water. The N2 adsorption–desorption
of the remaining SiO2 is shown in Fig. 2. Compared with SCF, the
Fig. 3. TEM image and size distribution of CF.

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Y. Zhang et al. / Applied Catalysis A: General 453 (2013) 327–333
a
b
MCF
MSCF
[ADIm][Br]/CF
[ADIm][OH]/CF
[ADIm][Br]/SCF
[ADIm][OH]/SCF
1600
1400
4000 3500 3000 2500 2000 1500 1000
500
4000 3500 3000 2500 2000 1500 1000
Wavenumbers / cm-1
500
-1
Wavenumbers / cm
Fig. 4. FTIR spectra of modified carriers and supported ionic liquids.
3.2. Structure and magnetism of [ADIm][OH]/SCF and
[ADIm][OH]/CF
assigned to [ADIm][Br] are covered by the strong peaks of M O
vibration (M = Fe or Co) and O Si O stretching vibrations. How-
ever, some characteristic peaks of [ADIm][Br] still can be found in
SCF and CF were modified with MPTMS to prepare MSCF and
MCF, and their structures were characterized by FTIR and TG–DTA.
Comparing with the FTIR spectra of SCF and CF shown in Fig. 1(b),
three of the peaks assigned to SCF (587 cm−1, 806 cm−1 and
1063 cm−1) and two of the peaks assigned to saturated C H bonds
(2946 cm−1 and 2844 cm−1) are present in the FTIR spectra of MSCF
and MCF, which are shown in Fig. 4. Furthermore, the peaks corre-
sponding to the superficial hydroxyl groups of MSCF and MCF are
smaller than those of SCF and CF, probably due to the consump-
tion in the reaction of superficial hydroxyl groups with MPTMS. It
is inferred that the sulfhydryl groups are successfully grafted on
SCF and CF. As shown in Fig. 5(a), the weight loss of modified SCF
and CF after calcined at 700 ◦C are 18.40% and 17.85%, which also
proved the modification on SCF and CF.
MSCF and MCF were then used to immobilize [ADIm][Br]
through a free radical reaction between allyl groups and sulfhydryl
groups. The [ADIm][Br] ionic liquid was synthesized, and the data
of FTIR and 1H NMR of [ADIm][Br] were list as follows: IR (KBr, v,
cm−1): 3130, 3062, 2926, 2854, 1562, 1466, 1376, 1089, 993, 942,
764, 720; 1H NMR (400 MHz, CDCl3) (ı, ppm): 0.795 (1H, t, C12H25),
1.239–1.149 (18H, br, C12H25), 1.846 (2H, m, C12H25), 4.257 (2H, t,
C12H25), 4.978 (2H, d, allyl group-H), 5.435 (2H, d, allyl group-H),
5.959 (1H, m, allyl group-H), 7.491 (1H, s, imidazole-H), 7.521 (1H,
s, imidazole-H), 10.310 (1H, s, imidazole-H).
the spectra when they are magnified, such as the peak at 1562 cm−1
,
assigned to the C N bond of imidazole ring. Elemental nitrogen,
which exists only in [ADIm][Br] and [ADIm][OH], is also detected in
the supported ionic liquids using organic element analysis (Table 1).
Both FTIR and nitrogen elemental analysis results indicate that
[ADIm][Br] has been immobilized onto modified carriers. Besides,
the amount of [ADIm][Br] ionic liquids supported on SCF is close
to that on CF, which can be seen from Table 1, while the amount
of [ADIm][OH] on SCF is less than that on CF. This might be due to
that the slight loss of silica immobilized with ionic liquids under a
strong basic environment during the ion-exchange process. Mean-
while, the loading amounts of ionic liquids immobilized calculated
from element analysis are less than the weight loss calculated from
TG–DTA, which owes to the degradation of other organic groups
and the loss of water adsorbed on the samples.
Additionally, comparing the TG curves of [ADIm][Br] and sup-
ported [ADIm][Br] samples shown in Fig. 5(a), it can be found
that the degradation temperatures of the latter have been post-
poned from 210 ◦C to 280 ◦C. That is to say, the thermal stability of
[ADIm][Br] immobilized on magnetic carriers improve obviously.
The crystal structure and magnetism of samples were charac-
terized by XRD and VSM. As shown in Fig. 5(b) and Table 2, all of
the samples own cobalt ferrite nanomagnets and present excellent
paramagnetism. XRD patterns and magnetization data of supported
ionic liquids differ little from those for their magnetic carriers,
which mean that the structure of cobalt ferrite is not destroyed
Compared with the FTIR data of [ADIm][Br], the FTIR spectra of
supported ionic liquids shown in Fig. 4 indicates that most of peaks
100
MSCF
a
b
80
[DIm][OH]/CF
[ADIm][Br]/SCF
[ADIm] OH]/SCF
60
40
20
[ADIm][Br]
[DIm][Br]/CF
MCF
0
100
MCF
[DIm][OH]/SCF
90
80
70
60
50
[DIm][Br]/SCF
MSCF
[ADIm][Br]/CF
[ADIm][OH]/CF
10
20
30
40
50
60
70
80
90
100
200
300
400
500
600
700
2
Temperature / ºC
Fig. 5. TG curves (a) and XRD patterns (b) of modified carriers and supported ionic liquids.

Y. Zhang et al. / Applied Catalysis A: General 453 (2013) 327–333
331
Table 1
Element analysis results of supported ionic liquids.
Samples
Element content (wt.%)
Loading amounta
Weight lossb (wt.%)
N
C
H
c (mmol/g)
w (wt.%)
[ADIm][Br]/SCF
[ADIm][OH]/SCF
[ADIm][Br]/CF
[ADIm][OH]/CF
0.7163
0.3836
0.6823
0.5313
12.7776
11.7203
15.8910
14.9473
2.7851
2.6569
3.1522
3.0388
0.2558
0.1370
0.2437
0.1897
11.00
5.03
10.48
6.96
20.00
24.54
19.43
21.71
a
Calculated from element analysis.
Calculated from TG–DTA.
b
Table 2
As the reaction time went from 1 h to 6 h, the contents of TG and
DG decreased and ME yield increase obviously, while the amount
of MG changed a little. After 6 h, no TG was left, and reactions
approached the equilibrium. For the transesterification catalyzed
by [ADIm][OH]/CF, the content of TG in the reaction system was
40.15% when the reaction time went to 1 h, less than the TG content
of 46.81% in the system catalyzed by [ADIm][OH]/SCF, and selec-
tivities of DG and MG and ME yield were much higher than that of
[ADIm][OH]/SCF. The similar circumstance last for 4 h. After 6 h TG
were used up and ME yield came up to 83.45%. Meanwhile, for the
transesterification catalyzed by [ADIm][OH]/SCF, both TG and DG
were used up and ME yield went up to 86.54%. For the transesteri-
fication catalyzed by conventional NaOH catalyst, the ME yield and
MG content were 59.02% and 45.50%, respectively. Both supported
ionic liquids showed much better catalytic activities than NaOH.
In this work, [ADIm][OH]/SCF and [ADIm][OH]/CF catalysts
have the same basic ionic liquid which work as catalytic sites,
and the difference between them is the structure of carriers. For
[ADIm][OH]/SCF catalyst, the catalytic sites were mainly immobi-
lized onto the mesopore walls of the SCF, as shown in Scheme 2.
When the reaction took place, TG with three long straight chains
had to transfer from the bulk into the pores of the catalysts to
contact with the active sites, and energy and time were needed
to conquer mass transfer resistance induced by the narrow pores
and the strong interaction between immobilized [ADIm][OH] and
glycerol trioleate. Whereas, for the catalyst of [ADIm][OH]/CF, all
the catalytic active sites are bare on the surface of catalysts and
spread in to the bulk freely, as it is much easier for reactants to
contact with catalytic sites. As a result, the conversion of TG in the
bulk phase catalyzed by [ADIm][OH]/SCF was lower at the begin-
ning, and correspondingly DG, MG and ME content were lower.
With the reaction time going on, TG in the system catalyzed by
[ADIm][OH]/SCF went into pores and reacted with methanol. The
long and confined pore made it difficult for TG and the following
intermediate of DG to leave, which increased the contact opportu-
nities for reactant and the intermediate with active sites until they
were consumed. In contrast, there was still some DG left in the sys-
tem catalyzed by [ADIm][OH]/CF. Based on the results above, the
mesoporous structure of SCF affected obviously the catalytic perfor-
mance of [ADIm][OH]/SCF. Although SCF particles were nanosized,
it was still difficult for TG with three long straight groups to pass
through the pores, and the following pore diffusion effect resulted
in the decrease of catalytic activity of [ADIm][OH]/SCF at the begin-
ning of the reaction and the increase of that when the reaction time
was long enough. In contrary, there was no pore existing in CF and
all the immobilized catalytic sites spread into the bulk freely, so
[ADIm][OH]/CF act similarly to homogeneous catalyst.
Magnetization data of supported ionic liquids.
Samples
Ms (emu/g)
Mr (emu/g)
Coercivity (G)
[ADIm][Br]/SCF
[ADIm][OH]/SCF
[ADIm][Br]/CF
[ADIm][OH]/CF
6.9088
6.8459
24.4000
24.7208
0.0040
0.0043
0.0261
0.0270
4.3011
4.4827
6.3210
3.8392
during immolization process. The excellent paramagnetism of sam-
ples makes magnetic separation to be available.
3.3. Catalytic transesterification reaction
TG transesterification is often catalyzed by acid or basic cata-
lysts. For the methanolysis of TG, glyceryl dioleate (noted as DG)
and methanol oleate (noted as ME) produced firstly through the
reaction between TG and methanol. Then DG reacted further with
methanol and yielded glyceryl monooleate (noted as MG) and ME.
Finally MG reacted with methanol and glycerin and ME yielded [25].
The catalytic performance of the two SILCs and NaOH was evalu-
ated using the catalytic transesterifications of TG with methanol. As
shown in Fig. 6, reaction time is favorable for catalytic transesterifi-
cations. When the reaction time went to 1 h, TG was consumed, and
a large amount of DG and a small amount of MG and ME produced.
100
80
CTG
CDG
CMG
CME
CTG
CDG
CMG
CME
60
40
20
0
10
80
60
40
20
0
YME
YME
SMG
SDG
SME
SMG
SDG
SME
Cycles of both catalysts have been shown in Fig. 7. For both of
the catalysts, the catalytic activities went down in three cycles.
This might be due to the loss of OH− or [ADIm][OH] on the surface
of carriers. For [ADIm][OH]/SCF, it still performed better catalytic
activity than fresh NaOH in second cycle, and showed better cat-
alytic activity than [ADIm][OH]/CF in three cycles. This might be
because that the pore diffusion effect of SCF had protected the active
0
1
2
3
4
5
6
Time / h
Fig. 6. Product contents, ME yield and product selectivities in TG transesterification
catalyzed by [ADIm][OH]/SCF (solid line + solid symbol) and [ADIm][OH]/CF (dashed
line + hollow symbol).

332
Y. Zhang et al. / Applied Catalysis A: General 453 (2013) 327–333
Scheme 2. Transesterification reactions of TG with methanol catalyzed by catalysts.
yield of ME
ME content
MG content
TG content
DG content
while CF particles are cobalt ferrite nanoparticles with average
size of 15 nm. Both catalysts showed excellent paramagnetism.
The two catalysts showed better catalytic activities than NaOH.
Reaction time favored the transesterifications. The mesoporous
structure of SCF affected obviously the catalytic performance of
[ADIm][OH]/SCF. The pore diffusion effect resulted in the decrease
of catalytic activity of [ADIm][OH]/SCF at the beginning of the
reaction and the increase of that when the reaction time was long
enough. When [ADIm][OH]/SCF was recycled, the pore diffusion
effect of SCF had protected the active sites immobilized on the
carrier to some extent and reduced the loss of them.
100
80
60
40
20
0
Acknowledgement
1
2
3
1
2
3
[ADIm][OH]/CF
[ADIm][OH]/SCF
This work was financially supported by the National Natural Sci-
ence Foundation of China (project nos.: 20706006 and 20976013).
Fig. 7. Cycles of two catalysts.
sites immobilized on the carrier to some extent and the loss of them
declined.
References
[1] H. Olivier-Bourbigou, L. Magna 1, D. Morvan, Appl. Catal. A: Gen. 373 (2010)
1–56.
[2] B. Zhen, Q.Z. Jiao, Y.P. Zhang, Q. Wu, H.S. Li, Appl. Catal. A: Gen. (2012),
http://dx.doi.org/10.1016/j.apcata.2012.08.023.
[3] B.Y. Liu, J. Han, J.F. Dong, F.X. Wei, Y.H. Cheng, Chin. J. Org. Chem. 27 (2007)
1236–1243.
[4] H. Vallette, S. Pican, C. Boudou, J. Levillainb, J.C. Plaqueventa, A.C. Gaumont,
Tetrahedron Lett. 47 (2006) 5191–5193.
[5] A. Riisager, R. Fehrmann, M. Haumann, P. Wasserscheid, Top. Catal. 40 (2006)
91–102.
4. Conclusions
Magnetic mesoporous [ADIm][OH]/SCF and magnetic
[ADIm][OH]/CF catalysts were prepared through immobiliz-
ing [ADIm][Br] onto magnetic carriers of SCF and CF followed by
the ion-exchange of OH− and used in the transesterification of glyc-
erol trioleate. Magnetic SCF nanoparticles consist of mesoporous
silica matrix and uniformly dispersed cobalt ferrite nanoparticles,
[6] A. Riisager, R. Fehrmann, M. Haumann, P. Wasserscheid, Eur. J. Inorg. Chem. 4
(2006) 695–706.

Y. Zhang et al. / Applied Catalysis A: General 453 (2013) 327–333
333
[7] J.Y. Li, J.J. Peng, Y. Bai, Y.Q. Hu, H.Y. Qiu, G.Q. Lai, X.N. Li, Phosphorus Sulfur
Silicon Relat. Elem. 185 (2010) 484–490.
[15] R. Abu-Reziq, D. Wang, M. Post, H. Alper, Adv. Synth. Catal. 349 (2007)
2145–2150.
[8] M.M. Dharman, H.J. Choi, D.W. Kim, D.W. Park, Catal. Today 164 (2011)
544–547.
[9] W.L. Dai, L. Chen, S.F. Yin, W.H. Li, Y.Y. Zhang, S.L. Luo, C.T. Au, Catal Lett. 137
(2010) 74–80.
[16] A. Taber, J.B. Kim, J.Y. Jung, W.S. Ahn, M.J. Jin, Synlett. 15 (2009) 2477–2482.
[17] X.X. Zheng, S.Z. Luo, L. Zhang, J.P. Cheng, Green Chem. 11 (2009) 455–458.
[18] Y.Y. Jiang, C. Guo, H.S. Xia, I. Mahmood, C.Z. Liu, H.Z. Liu, J. Mol. Catal. B-Enzym.
58 (2009) 103–109.
[10] Z.J. Xu, H. Wan, J.M. Miao, M.J. Han, C. Yang, G.F. Guan, J. Mol. Catal. A 332 (2010)
152–157.
[11] D.W. Kim, D.O. Lim, D.H. Cho, J.C. Koh, D.W. Park, Catal. Today 164 (2011)
556–560.
[12] H. Wang, B. Wang, C.L. Liu, W.S. Dong, Micropor. Mesopor. Mater. 134 (2010)
51–57.
[13] K.K. Kang, S.A. Jung, H.K. Rhee, J. Chin. Inst. Chem. Eng. 37 (2006) 17–23.
[14] H.H. Zhao, N.Y. Yu, Y. Ding, R. Tan, C. Liu, D.H. Yin, H.Y. Qiu, D.L. Yin, Micropor.
Mesopor. Mater. 136 (2010) 10–17.
[19] Q. Zhang, H. Su, J. Luo, Y.Y. Wei, Green Chem. 14 (2012) 201–208.
[20] Y. Zhang, Y.W. Zhao, C.G. Xia, J. Mol. Catal. A: Chem. 306 (2009) 107–112.
[21] Y. Zhang, C.G. Xia, Appl. Catal. A: Gen. 366 (2009) 141–147.
[22] Y.P. Zhang, H.S. Li, B. Zhen, Q. Wu, C.H. Liu, Adv. Mater. Res. 197–198 (2011)
269–272.
[23] B.C. Ranu, S. Banerjee, Org. Lett. 7 (2005) 3049–3052.
[24] R. De Palma, S. Peeters, M.J. Van Bael, H. Van den Rul, K. Bonroy, W. Laureyn, J.
Mullens, G. Borghs, G. Mae, Chem. Mater. 19 (2007) 1821–1831.
[25] D.S. Martino, T. Riccardo, P.M. Lu, S. Elio, Energy Fuels 22 (2008) 207–217.