Synthesis of mesoporous sapo-34 molecular sieves and their applications in dehydration of butanols and ethanol

Article abstract of DOI:10.1166/jnn.2013.7387

Microporous SAPO-34 molecular sieves were hydrothermally synthesized with microwave irradiation in the presence of tetraethylammonium hydroxide (TEAOH) as a template. SAPO-34 molecular sieves with mesoporosity were also prepared in the presence of carbon black as a hard template. By increasing the content of the carbon black template in the synthesis, the mesopore volume increased. Dehydration of alcohols (butanols and ethanol) was carried out with the synthesized SAPO-34 molecular sieves, and the lifetime of the catalysts for the dehydration reaction increased as the mesoporosity increased. Moreover, the performance of the microporous catalyst synthesized with microwave was better than that of the catalyst obtained with conventional electric heating. The relative performance of the catalytic dehydration may be explained by the mesoporosity and the crystal size. Therefore, it may be concluded that small-sized SAPO-34 molecular sieves with high mesoporosity can be produced efficiently with microwave irradiation in the presence of carbon black template, and the molecular sieves are effective in the stable dehydration of alcohols. Copyright

Full text of DOI:10.1166/jnn.2013.7387

Copyright © 2013 American Scientific Publishers
All rights reserved
Printed in the United States of America
Journal of
Nanoscience and Nanotechnology
Vol. 13, 2782–2788, 2013
Synthesis of Mesoporous SAPO-34 Molecular
Sieves and Their Applications in
Dehydration of Butanols and Ethanol
1
1
2
2
Jong Won Jun , Jaewoo Jeon , Chul-Ung Kim , Kwang-Eun Jeong ,
2
1ꢀ∗
Soon-Yong Jeong , and Sung Hwa Jhung
1Department of Chemistry and Green-Nano Materials Research Center, Kyungpook National University,
Daegu 702-701, Republic of Korea
2
Research Center for Green Catalysis, Division of Green Chemistry and Engineering Research,
Korea Research Institute of Chemical Technology, P.O. Box 107, 141 Gajeong-ro,
Yuseong, Daejeon 305-600, Republic of Korea
Microporous SAPO-34 molecular sieves were hydrothermally synthesized with microwave irradiation
in the presence of tetraethylammonium hydroxide (TEAOH) as a template. SAPO-34 molecular
sieves with mesoporosity were also prepared in the presence of carbon black as a hard template.
By increasing the content of the carbon black template in the synthesis, the mesopore volume
increased. Dehydration of alcohols (butanols and ethanol) was carried out with the synthesized
SAPO-34 molecular sieves, and the lifetime of the catalysts for the dehydration reaction increased
as the mesoporosity increased. Moreover, the performance of the microporous catalyst synthesized
Delivered by Ingenta to: Purdue University Libraries
with microwave was better than that of the catalyst obtained with conventional electric heating. The
IP: 79.110.28.66 On: Wed, 18 May 2016 17:24:30
relative performance of the catalytic dehydration may be explained by the mesoporosity and the
Copyright: American Scientific Publishers
crystal size. Therefore, it may be concluded that small-sized SAPO-34 molecular sieves with high
mesoporosity can be produced efficiently with microwave irradiation in the presence of carbon black
template, and the molecular sieves are effective in the stable dehydration of alcohols.
Keywords: Mesoporous SAPO-34, Carbon Black Template, Microwave-Synthesis, Dehydration
of Alcohols, Stability in Dehydration.
1
. INTRODUCTION
nanoporous materials have been synthesized with rela-
2
0ꢀ21
tively new methods such as microwave (MW)
ultrasound irradiations. Especially, it has been reported
that synthesis of nanoporous materials by microwave heat-
and
Nanoporous materials including zeolites, aluminophos-
phate (AlPO)/silicoaluminophosphate (SAPO) molecular
22
sieves1 and mesoporous materials are widely used in
ꢀ2
3–7
2
0ꢀ21
ing has many advantages such as fast crystallization,
catalysis, adsorption, separation, and biomedicine and have
been studied for other applications. The SAPO-34 molec-
ular sieve with a CHA structure is one of the molecular
sieves containing small pores (pore size of 0.38 nm) com-
posed of 8-membered rings and has attracted much inter-
2
3ꢀ24
25–28
facile morphology control,
phase-selectivity
and
8
2
9ꢀ30
ready evaluation of process parameters.
Moreover, the
MW technique has been regarded as an effective way to
synthesize small-sized crystals because of the high con-
9
3
1
centration of nuclei and homogeneous heating.
est not only for fundamental understanding but also for
applications including catalysis called ‘methanol-to-olefin’
3
2–35
36–38
Recently, zeolites
and SAPOs
with mesoporos-
1
0–15
16
ity have been reported for syntheses and applications
including the dehydration of alcohols. Park and cowork-
ers have shown that microwave irradiation, compared to
conventional electric heating, has a beneficial effect on the
(
MTO) process
So far, nanoporous materials including zeolites and
metal-organic frameworks (MOFs, materials composed of
and selective adsorption/separation.
1
7–19
not only inorganic clusters but also organic linkers)
have been synthesized mainly by hydrothermal crystalliza-
tion using conventional electric (CE) heating. Recently,
3
2–34
production of mesoporous MFI molecular sieves.
They
also demonstrated that mesoporous MFI molecular sieves
3
2–34
were very efficient in catalysis for large molecules.
Ryoo and coworkers synthesized mesoporous MFI for
∗
Author to whom correspondence should be addressed.
2
782
J. Nanosci. Nanotechnol. 2013, Vol. 13, No. 4
1533-4880/2013/13/2782/007
doi:10.1166/jnn.2013.7387

Jun et al.
Synthesis of Mesoporous SAPO-34 Molecular Sieves and Their Applications in Dehydration of Butanols and Ethanol
methanol-to-hydrocarbon reactions, and found that the cat-
alyst life time was increased with the mesoporosity.
Therefore, it is highly desirable to synthesize small
and mesoporous SAPO-34 molecular sieves and to eval-
uate the SAPO-34s in the dehydration of butanols and
ethanol. In this study, a facile synthesis method to pro-
duce small/mesoporous SAPO-34s was developed with
MW irradiation and carbon black (as a hard template for
mesoporosity). Moreover, dehydration of simple alcohols
was studied to understand the effect of mesoporosity and
crystal size on the performance of dehydration including
the catalyst lifetime and product selectivity.
3
5
Compared with mesoporous zeolites such as MFI
molecular sieves, mesoporous AlPOs or SAPOs, espe-
cially mesoporous SAPO-34, have not been investigated
all that much. Mesoporous SAPO-34 was synthesized
3
6
from as-synthesized SBA-15 as a silica source. Mono-
lithic mesoporous SAPO-34 was also synthesized using
3
7
a dry gel conversion. Floral mesoporous SAPO-34 was
obtained from a hydrothermal synthesis in the presence of
NaF.38 Very recently, mesoporous SAPO-34 was synthe-
sized in the presence of a soft template ([3-(trimethoxy-
silyl)propyl]octadecyldimethyl-ammonium chloride) and
2. EXPERIMENTAL DETAILS
3
9
applied in MTO process. To the best of our knowledge,
only one report has been published very recently for the
synthesis of mesoporous SAPO-34 by using a simple hard
SAPO-34 molecular sieves were synthesized from pseu-
doboehmite (Catapal A, Vista), phosphoric acid (85 wt.%,
Aldrich), silica sol (Ludox AS-40, 40%, Aldrich)
and deionized water similar to previously described
4
0
template (carbon black and carbon nanotube) even though
3
2–34
there are a few reports
on mesoporous ZSM-5 from car-
4
2ꢀ43
methods.
Tetra-ethylammonium hydroxide (TEAOH,
bon black. Because of the difference in chemistry between
the synthesis of ZSM-5 (alkaline precursor without H PO )
35%, Aldrich) was used as a template molecule
3
4
since TEAOH selectively led to SAPO-34 under MW
and SAPO-34 (acidic precursor containing H PO ) it will
3
4
43
irradiation. Silica sol was added dropwise to the aque-
be interesting to prepare mesoporous SAPO-34 with car-
bon black for both its use in various applications and its
fundamental understanding.
ous solution of TEAOH and mixed well, and the mix-
ꢀ
ture was aged at 100 C for 12 h. Phosphoric acid
was added dropwise to pseudoboehmite which was sus-
pended in water. Finally the mixtures of silica and TEAOH
were added to the white gel of the aluminophosphates,
Even though, MW-assisted synthesis of molecular sieves
has several advantages, to the best of our knowledge, there
are only a few reports on the synthesis of SAPO-34 molec-
Delivered by Ingenta to: Pur rde us ue l tUi n ng iv ien rst iht ye Lr ei ba rc at ar ine tscomposition of Al O :1.0P O :
3
9ꢀ41–43
2
3
2
5
ular sieves with this technique.
SAPO-34 has been
IP: 79.110.28.66 On: Wed, 18 May 2016 17:24:30
.3SiO :2.0TEAOH:100H O. For mesoporous SAPO-34s,
0
2
2
successfully synthesized, under microwave heating, by a
Copyright: American Scientific Publishers
4
1
carbon black (30 or 60 wt.% of the used pseudoboehmite)
was added to the reaction gels and mixed well for 12 h. Car-
bon black (Black Pearls 2000) was obtained from the Cabot
corporation and has an average particle size of ∼12 nm.
The reaction conditions for the representative cases are
shown in Table I.
transformation of SAPO-5. Van Heyden et al. synthe-
sized a nanosized SAPO-34 from clear colloidal precursor
solutions.42 Recently, we have reported the MW synthe-
sis of SAPO-34 using a template of TEAOH under a very
4
3
limited condition.
Dehydration of an alcohol including the MTO process is
very important for producing olefins or converting cheap
feedstocks into valuable chemicals. SAPO-34 is one of the
A gel of ∼20 g was loaded in a 100 ml Teflon
autoclave, which was sealed and placed in a microwave
oven (Mars-5, CEM, maximum power of 1200 W). The
autoclave was heated to the reaction temperature of
1
0–15
most deeply studied catalysts for the MTO process.
Generally, a small-sized SAPO-34 is superior to a large-
ꢀ
1
0–12
190–195 C in about 2 min and kept for a predetermined
sized one in catalysis (including the MTO process
),
time. The microwave power was 300 W throughout all the
especially for steady conversion. Moreover, mesoporous
SAPO-34 was superior to conventional SAPO-34 in the
MTO process, especially in terms of the lifetime of the
catalyst.3
Table I. Reaction conditions and textural properties of the synthesized
SAPO-34 molecular sieves.
6ꢀ37ꢀ39
Recently, simple alcohols like ethanol and butanols
have attracted much attention as renewable fuels and
b
Reaction conditions
Method/temp./time
Textural properties
4
4
chemicals. Ethanol and butanols can be produced from
a
c
d
e
Sample no.
S
PV
PV
BET
total
meso
4
4
biomass by fermentation, therefore; they are usually
called bioalcohols. Moreover, valuable olefins like ethy-
lene and butylenes may be obtained from bioalcohols via
simple dehydration. As the production of bioalcohols is
increasing, the competitiveness of the process to produce
olefins from bioalcohols will be increased. Even though
there has been much effort for the MTO process, rela-
tively little attention has been focused on the dehydration
of bioethanol or biobutanol.
ꢀ
CE(0)
CE/190 C/2 d
454
417
424
364
0.36
0.16
ꢀ
ꢀ
ꢀ
MW(0)
MW(30)
MW(60)
MW/190 C/2 h
0.33
0.40
0.55
0.19
0.24
0.46
MW/195 C/3 h
MW/195 C/3 h
a
Notes: The figures in the parentheses mean the weight of carbon black
weight% of the used pseudoboehmite); The molar composition of reactants is
Al O :1.0P O :0.30SiO :2.0TEAOH:100H O; MW: microwave heating; CE: con-
ventional electric heating; cBET surface area (m2/g); dTotal pore volume (cm3/g);
b
(
2
3
2
5
2
2
e
3
Mesopore volume (cm /g).
J. Nanosci. Nanotechnol. 13, 2782–2788, 2013
2783

Synthesis of Mesoporous SAPO-34 Molecular Sieves and Their Applications in Dehydration of Butanols and Ethanol
Jun et al.
synthesis steps including the heating-up stage. The reac-
tion temperature was controlled using the EST-300 Plus
system (Electronic Sensor—Temperature) that monitored
and controlled temperature conditions inside the sample
vessels. The detailed synthesis procedure under microwave
3. RESULTS AND DISCUSSION
Figure 1 shows the XRD patterns of the calcined molecu-
lar sieves synthesized by both conventional electric heating
and microwave (with or without carbon black) irradi-
ation, from gels containing TEAOH (reactant composi-
tion is Al O :1.0P O :0.30SiO :2.0TEAOH:100H O). The
4
5ꢀ46
irradiation was reported elsewhere.
For a conventional
2
3
2
5
2
2
electric crystallization, the gel (∼20 g) was loaded in a
XRD patterns did not change appreciably with heating
methods or with the incorporation of carbon black for
mesoporosity. The XRD patterns match with the calcu-
lated pattern of SAPO-34, showing the successful syn-
thesis of SAPO-34 under the investigated conditions. The
SEM images (Fig. 2) of typical SAPO-34s, after calcina-
tion, show that the particle size distribution is wide and the
size is a bit large (compared with the SAPO-34 obtained
with microwaves) when the SAPO-34 was obtained with
CE synthesis (Fig. 2(a)). However, the size is quite small
when SAPO-34 was obtained with MW heating (Figs. 2(b)
and (c)).
Teflon lined autoclave and put in a preheated electric oven
ꢀ
(
190 C) for 2 d. During the microwave and conventional
reactions, the reactant mixtures were kept without agita-
tion. After the reaction, the autoclave was cooled to room
temperature and solid products were recovered by cen-
ꢀ
trifugation and dried overnight at 100 C. The obtained
SAPO-34 molecular sieves were calcined for 10 h at
ꢀ
5
50 C in air under static condition in order to remove
the TEAOH and carbon black (if any). The SAPO-34s
were designated as CE(0), MW(0), MW(30) and MW(60)
depending on the heating methods (CE or MW) and the
content of carbon black in the reaction mixtures. The
figures in the parentheses mean the content of the carbon
black (relative weight% to pseudoboehmite) used in the
syntheses.
The crystal phase of the samples was verified using an
X-ray diffractometer (D2 Phaser, Bruker, CuKꢁ radiation).
The morphology was examined using a scanning electron
The synthesized SAPO-34s, after calcination, were ana-
lyzed for porosity. As shown in Figure 3, the nitrogen
adsorption isotherms of typical SAPO-34s (CE(0) and
MW(0), synthesized without carbon black) had isotherms
of type-I, showing the microporosity of the SAPO-34
samples. However, SAPO-34s synthesized from gels con-
taining carbon black showed hysteresis loops from P/P0
of ∼0.8 (Fig. 3(a)), confirming the mesoporosity in the
microscope (Hitachi, S-4300). The nitrogen adsorption
ꢀ
isotherms and surface areas we Dr ee l mi v ee ar se ud r ebd y aI nt g−e 1n 9t a6 t oC: Purdue University Libraries
SAPO-34s such as MW(30) and MW(60). Moreover, the
with a surface area and porosi tI yP :a 7n 9a l. y1 z1 e 0r . 2( M8 . 6i c 6r o Om ne :r i Wt - ed, 18 May 2016 17:24:30
pore size distributions (Fig. 3(b)) confirm the presence of
mesopores in the samples of the MW(30) and MW(60).
The pore size was a little larger than the particle size of
the carbon black (∼12 nm) and did not change apprecia-
bly with the content of the carbon black. The pore size
of the mesoporous SAPO-34s, compared with the particle
size of the carbon black, confirms the templating role of
the carbon black for mesoporosity. Table I also shows that
both the total pore volume and mesopore volume increased
steadily with increasing the content of the carbon black
Copyright: American Scientific Publishers
ꢀ
ics, Tristar II 3020) after evacuation at 300 C. The sur-
face area was calculated with the BET equation, and
the pore size distribution in the mesopore region was
obtained with the Barrett–Joyner–Halenda (BJH) method.
Ammonia-temperature programmed desorption (TPD) pat-
tern was obtained with an Automated Catalyst Character-
ization System (Micromeritics, AutoChem II 2920) after
adsorbing ammonia (15% ammonia in helium, flow rate
ꢀ
5
1
0 cc/min) at 100 C for 1 h and sweeping for 30 min at
ꢀ
00 C (helium 30 cc/min). Desorption of adsorbed ammo-
nia was performed between 100 and 600 C with a ramp-
ing rate of 10 C/min under a helium flow (30 cc/min).
ꢀ
ꢀ
Before adsorption, the SAPO-34s were pre-treated with
a helium flow (50 cc/min) under heat. The temperature
MW (60)
MW (30)
ꢀ
was increased from 30 to 500 C with a heating rate of
ꢀ
ꢀ
1
0 C/min and maintained for 3 h at 500 C.
The dehydration of alcohols to olefins was carried out at
atmospheric pressure with a conventional fixed-bed reac-
tor made of a stainless steel tube. The alcohols were fed
with a syringe pump and nitrogen (30 cc/min) was used
MW (0)
CE (0)
ꢀ
as a carrier gas. The SAPO-34 calcined at 550 C was
ꢀ
dehydrated at 450 C for 2 h before the reaction. The
Calculated SAPO-34
−
1
weight hourly space velocity (WHSV) was 2 h for var-
ious alcohols and the weight of SAPO-34 catalyst was
5
10
15
2
20
25
30
0
.2 g. Products and fed alcohols were analyzed with an on-
theta (deg)
lined GC equipped with a flame ionization detector (FID)
detector.
Fig. 1. XRD patterns of the obtained SAPO-34 molecular sieves.
J. Nanosci. Nanotechnol. 13, 2782–2788, 2013
2
784

Jun et al.
Synthesis of Mesoporous SAPO-34 Molecular Sieves and Their Applications in Dehydration of Butanols and Ethanol
4
3
3
2
2
1
1
00
50
00
50
00
50
00
(a)
MW (60)
MW (30)
MW (0)
CE (0)
0.6
5
0
0
0
.0
0.2
0.4
0.8
1.0
Relative pressure (P/Po)
1.4 (b)
1
1
0
0
0
0
0
.2
.0
.8
.6
.4
.2
MW (60)
MW (0)
CE (0)
MW (30)
.0
0
10
20
30
40
50
60
70
Pore diameter (nm)
Delivered by Ingenta to: Purdue University Libraries
IP: 79.110.28.66 On: Wed, F1i g8 . 3M. a (ya )2 N0 i 1t r o6 g e1n 7 a: d2 s 4o r: p3 t i0o n/desorption isotherms and (b) pore size
Copyright: American S dc ii set r ni bt ui ft ii co n Ps ou fbSl Ai s Ph Oe - r3 s4 molecular sieves.
The acidity of SAPO-34s was analyzed with ammonia
TPD (Fig. 4) and there was little effect of size and meso-
porosity on the acidity of the SAPO-34s. The general pat-
terns of ammonia TPD of the SAPO-34s are very similar to
3
9
those observed earlier. The SAPO-34s have not only weak
but also strong acid sites; therefore, those materials can be
used in acid catalysis such as dehydration of alcohols.
Fig. 2. SEM images of the obtained SAPO-34 molecular sieves:
(
a) CE(0); (b) MW(0) and (c) MW(60).
in the synthesis. Therefore, it can be concluded that the
mesoporosity of SAPO-34 increases as the content of the
carbon black increases, similar to the results of Park et al.
3
2–34
in the synthesis of MFI zeolites.
Mesoporosity is important because of the beneficial role
of fast diffusion or short path-length for reactants or prod-
ucts. Therefore, mesoporous zeolites or SAPOs have been
MW (60)
MW (0)
CE (0)
3
2–34
used not only for big molecules
but also for stable
3
5–37
catalysis like dehydrations.
Based on the pore size,
it is clear that the hard template of the carbon black is very
efficient in producing mesoporosity in SAPO-34 molec-
3
6–38
ular sieves. Compared with other synthesis methods
for mesoporous SAPO-34s, this method with carbon black
is very simple and the mesopore volume can be eas-
ily controlled. In other words, the mesopore volume can
be increased with as the content of the carbon black is
increased and the pore size may also be controlled by
using carbon blacks with various particle sizes.
100
200
300
400
500
600
Temperature (ºC)
Fig. 4. Ammonia TPD patterns of the SAPO-34 molecular sieves.
J. Nanosci. Nanotechnol. 13, 2782–2788, 2013
2785

Synthesis of Mesoporous SAPO-34 Molecular Sieves and Their Applications in Dehydration of Butanols and Ethanol
Jun et al.
1
00
Figure 5 shows the reaction results of 1-butanol dehy-
dration at 300 C over the SAPO-34s. The conversions into
(a)
ꢀ
Conversion
Ethylene
Propylene
8
6
4
2
0
0
0
0
0
butenes were quite stable even though the CE(0) showed
relatively rapid decrease in the conversion. There were few
differences in the product selectivity excluding the rela-
tively high selectivity for 1-butene over CE(0) especially
at long reaction time. Irrespective of the acidity or basic-
ity of the catalysts, the first product obtained from the
dehydration of 1-butanol is 1-butene, and 2-butenes can
1-Butene
t-2-Butene
c-2-Butene
4
7ꢀ48
be obtained via isomerization of 1-butene.
Therefore,
high selectivity for 1-butene means low activity of the cat-
alysts. The observed high selectivity of 1-butene over the
1
2
3
4
5
6
7
8
Time (h)
1
00
(b)
100
Conversion
Ethylene
Propylene
8
6
4
2
0
0
0
0
0
80
MW (60)
1-Butene
t-2-Butene
c-2-Butene
MW (30)
(a)
6
4
2
0
0
0
0
MW (0)
CE (0)
1
2
3
4
5
6
7
8
1
2
3
4
5
6
7
8
Time (h)
Time (h)
Delivered by Ingenta to: Purdue University Libraries
1
00
100
IP: 79.110.28.66 On: Wed, 18 May 2016 17:24:30
MW (60)
MW (30)
MW (0)
Conversion
Ethylene
Propylene
Copyright: A(cm) erican Scientific Publishers
8
6
4
2
0
0
0
0
0
90
1-Butene
t-2-Butene
c-2-Butene
(b)
8
7
6
5
0
0
0
0
CE (0)
1
2
3
4
5
6
7
8
1
2
3
4
5
6
7
8
Time (h)
Time (h)
MW (60)
MW (30)
MW (0)
1
00
100
Conversion
Ethylene
Propylene
(d)
8
6
4
2
0
0
0
0
0
1-Butene
(c)
t-2-Butene
c-2-Butene
9
8
7
0
0
0
CE (0)
1
2
3
4
5
6
7
8
1
2
3
4
5
6
7
8
Time (h)
Time (h)
Fig. 5. Conversion of 1-butanol and selectivities of olefins over SAPO-
Fig. 6. Conversion of 1-butanol over SAPO-34 molecular sieves at var-
ious temperatures: (a) 250 C; (b) 300 C; (c) 350 C. Note that the
ꢀ
ꢀ
ꢀ
ꢀ
34 molecular sieves (at 300 C): (a) CE(0); (b) MW(0); (c) MW(30) and
(
d) MW(60).
y-axes are in different scales.
2
786
J. Nanosci. Nanotechnol. 13, 2782–2788, 2013

Jun et al.
Synthesis of Mesoporous SAPO-34 Molecular Sieves and Their Applications in Dehydration of Butanols and Ethanol
ꢀ
and 350 C). With increasing reaction temperatures, the
100
stability (or conversion) of the catalysts for the dehydration
reaction increased. Remarkably, irrespective of the tem-
perature, the stability of the SAPO-34s for dehydration
increased in the order of CE(0) < MW(0) < MW(30) <
MW(60). A similar tendency of stability was also observed
8
6
4
2
0
0
0
0
0
MW (60)
MW (30)
MW (0)
in the dehydration of 2-butanol and ethanol at 175 and
ꢀ
2
75 C, respectively, as shown in Figure 7. However, the
selectivity over the SAPO-34s was not dependent much
on the mesoporosity or crystal size (Figs. 5 and 8), show-
ing little effect of the crystal size or mesoporosity on the
reaction mechanism or product distribution. The more sta-
ble performance of MW(0) in the dehydrations, compared
with the CE(0), might be due to the smaller crystal size
of the MW(0), in accordance with the reported results in
CE (0)
(
a)
1
2
3
4
5
6
7
8
Time (h)
100
MW (60)
MW (0)
1
0–12ꢀ49
MTO.
Moreover, it can also be understood that the
stability of SAPO-34 increases as the mesoporosity of the
SAPO-34s increases originating from the carbon black,
which is quite similar to the results in the dehydration of
9
8
7
6
0
0
0
0
3
5–37
CE (0)
methanol over various mesoporous materials.
There-
fore, it may also be concluded that the effect of crystal
size and mesoporosity on the stability or lifetime of cata-
lysts for the dehydration of butanols and ethanol is similar
1
0–12ꢀ35–37ꢀ49
to that for the dehydration of methanol.
(
b)
1
2
3
4
5
6
7
8
4
. CONCLUSION
Time (h)
Delivered by Ingenta to: Purdue University Libraries
IP: 79.110.28.66 On: Wed, M1 8e s Mo pao yr o2u 0s 1 6S A1 P7 O: 2- 43 :43 0molecular sieves could be syn-
Fig. 7. Conversion of (a) 2-butanol and (b) ethanol over SAPO-34
molecular sieves at 175 C and 275 C, respectively. Note that the y-axes
Copyright: American S tc hi ee sn i tz i ef i dc Pw ui bt hl is ch aer rb so n black as a hard template under
ꢀ
ꢀ
microwave irradiation. As the content of the carbon black
increased the mesopore volume of the SAPO-34s increased,
suggesting facile synthesis of the mesoporous SAPO-34s
for adsorption and catalysis because of rapid diffusion. The
stability of the catalysts for the dehydration of alcohols
increased as the mesoporosity of the SAPO-34s increased.
Based on the results in this study, it can be concluded that
SAPO-34 molecular sieves with high mesoporosity can be
produced efficiently by applying carbon black as a hard
template, and the molecular sieves are stable, probably
because of the mesoporosity, in the dehydration of alcohols
to produce olefins. Moreover, it may also be concluded that
the effect of crystal size and mesoporosity on the stability
of catalysts for the dehydration of butanols and ethanol is
similar to that for the dehydration of methanol.
are in different scales.
CE(0) might be due to decreased activity or poor stability
(see below) of CE(0), hindering the conversion of 1-butene
to 2-butenes.
Figure 6 summarizes the conversion of 1-butanol over
the four SAPO-34s at three temperatures (250, 300
6
5
4
3
2
1
0
0
0
0
0
0
0
t-2-butene
c-2-butene
1-butene
Acknowledgment: This Research has been performed
as a cooperation project and supported by the Korea
Research Institute of Chemical Technology (KRICT). This
work was also supported by Kyungpook National Univer-
sity Research Fund, 2012.
CE (0)
MW (0)
MW (30)
MW (60)
References and Notes
Fig. 8. Olefins selectivities in the 2-butanol dehydration over various
SAPO-34 molecular sieves at the same conversion of 60% (obtained at
different reaction times for different catalysts). The reaction temperature
1. S. T. Wilson, B. M. Lok, C. A. Messina, T. R. Cannan, and E. M.
Flanigen, J. Am. Chem. Soc. 104, 1146 (1982).
2. S. T. Wilson, Stud. Surf. Sci. Catal. 137, 229 (2001).
ꢀ
was 175 C.
J. Nanosci. Nanotechnol. 13, 2782–2788, 2013
2787

Synthesis of Mesoporous SAPO-34 Molecular Sieves and Their Applications in Dehydration of Butanols and Ethanol
Jun et al.
3. K. Ariga, A. Vinu, Y. Yamauchi, Q. Ji, and J. P. Hill, Bull. Chem.
Soc. Jpn. 85, 1 (2012).
26. S. H. Jhung, T. Jin, Y. H. Kim, and J.-S. Chang, Microporous Meso-
porous Mater. 109, 58 (2008).
4. Z. Li, J. C. Barnes, A. Bosoy, J. F. Stoddart, and J. I. Zink, Chem.
Soc. Rev. 41, 2590 (2012).
27. S. H. Jhung, T. Jin, J.-S. Hwang, and J.-S. Chang, J. Nanosci. Nan-
otech. 7, 2734 (2008).
5
6
. F. Tang, L. Li, and D. Chen, Adv. Mater. 24, 1504 (2012).
. K. Ariga, A. Vinu, M. Miyahara, J. P. Hill, and T. Mori, J. Am.
Chem. Soc. 129, 11022 (2007).
28. N. A. Khan and S. H. Jhung, Cryst. Growth Des. 10, 1860 (2010).
29. S. H. Jhung, J.-S. Chang, Y. K. Hwang, and S.-E. Park, J. Mater.
Chem. 14, 280 (2004).
7
. K. Ariga, A. Vinu, Q. Ji, O. Ohmori, J. Hill, S. Acharya, J. Koike,
and S. Shiratori, Angew. Chem. Int. Ed. 47, 7254 (2008).
. M. E. Davis, Nature 417, 813 (2002).
30. S. H. Jhung, J.-S. Chang, J. W. Yoon, J.-M. Grenèche, G. Férey, and
A. K. Cheetham, Chem. Mater. 16, 5552 (2004).
31. S. H. Jhung, T. Jin, Y.-K. Hwang, and J.-S. Chang, Chem. Eur. J.
13, 4410 (2007).
8
9
. http://www.iza-structure.org/databases/.
1
1
1
1
0. N. Nishiyama, M. Kawaguchi, Y. Hirota, D. Van Vu, Y. Egashira,
and K. Ueyama, Appl. Catal. A: General 362, 193 (2009).
1. K. Y. Lee, H.-J. Chae, S.-Y. Jeong, and G. Seo, Appl. Catal. A:
General 369, 60 (2009).
32. J.-B. Koo, N. Jiang, S. Saravanamurugan, M. Bejblova, Z. Musilová,
J. Èejka, and S.-E. Park, J. Catal. 276, 327 (2010).
33. D.-Y. Ok, N. Jiang, E. A. Prasetyanto, H. Jin, and S.-E. Park, Micro-
porous Mesoporous Mater. 141, 2 (2011).
34. H. Jin, M. B. Ansari, E.-Y. Jeong, and S.-E. Park, J. Catal. 291, 55
(2012).
35. J. Kim, M. Choi, and R. Ryoo, J. Catal. 269, 219 (2010).
36. Y. Liu, L. Wang, J. Zhang, L. Chen, and H. Xu, Microporous Meso-
porous Mater. 145, 150 (2011).
2. Y.-J. Lee, S.-C. Baek, and K.-W. Jun, Appl. Catal. A: General
329, 130 (2007).
3. D. S. Wragg, R. E. Johnsen, M. Balasundaram, P. Norby,
H. Fjellvåg, A. Grønvold, T. Fuglerud, J. Hafizovic, Ø. B. Vistad,
and D. Akporiaye, J. Catal. 268, 290 (2009).
14. A. Izadbakhsh, F. Farhadi, F. Khorasheh, S. Sahebdelfar, M. Asadi,
and Y. Z. Feng, Appl. Catal. A: General 364, 48 (2009).
37. H. Yang, Z. Liu, H. Gao, and Z. Xie, J. Mater. Chem. 20, 3227
(2010).
1
5. B. P. C. Hereijgers, F. Bleken, M. H. Nilsen, S. Svelle, K.-P. Lillerud,
M. Bjørgen, B. M. Weckhuysen, and U. Olsbye, J. Catal. 264, 77
38. Y. Liu, L. Wang, and J. Zhang, Mater. Lett. 65, 2209 (2011).
39. S.-T. Yang, J.-Y. Kim, H.-J. Chae, S.-Y. Jeong, and W.-S. Ahn,
Mater. Res. Bull. 47, 3888 (2012).
40. F. Schmidt, S. Paasch, E. Brunner, and S. Kaskel, Microporous
Mesoporous Mater. 164, 214 (2012).
(
2009).
6. Y. Tian, L. Fan, Z. Wang, S. Qiu, and G. Zhu, J. Mater. Chem.
9, 7698 (2009).
1
1
1
1
7. G. Férey, Chem. Soc. Rev. 37, 191 (2008).
8. S. Kitagawa, R. Kitaura, and S.-I. Noro, Angew. Chem. Int. Ed.
41. S. R. Venna and M. A. Carreon, J. Mater. Chem. 19, 3138
(2009).
4
3, 2334 (2003).
42. H. van Heyden, S. Mintova, and T. Bein, Chem. Mater. 20, 2956
(2008).
1
2
2
2
2
9. Yaghi, M. O’Keeffe, N. W. Ockwig, H. K. Chae, M. Eddaoudi, and
J. Kim, Nature 423, 705 (2003).
0. S.-E. Park, J.-S. Chang, Y. K. Hwang, D. S. Kim, S. H. Jhung, and
J. S. Hwang, Catal. Survey Asia 8, 91 (2004).
1. G. A. Tompsett, W. C. Conner, and K. S. Yngvesson, Chem. Phys.
Chem. 7, 296 (2006).
43. J. W. Jun, J. S. Lee, H. Y. Seok, J.-S. Chang, J.-S. Hwang, and S. H
Delivered by Ingenta to: Purdue University Libraries
Jhung, Bull. Kor. Chem. Soc. 32, 1957 (2011).
IP: 79.110.28.66 On: Wed, 18 May 2016 17:24:30
44. J. Swana, Y. Yang. M. Behnam, and R. Thompson, Bioresource Tech-
Copyright: American Scientific Publishers
nol. 102, 2112 (2011).
45. S. H. Jhung, J. W. Yoon, J.-S. Hwang, A. K. Cheetham, and J.-S.
Chang, Chem. Mater. 17, 4455 (2005).
46. S. H. Jhung, J.-S. Chang, Y. K. Hwang, J.-M. Grenèche, G. Férey,
and A. K. Cheetham, J. Phys. Chem. B 109, 845 (2005).
47. S. Delsarte and P. Grange, Appl. Catal. A: General 259, 269
(2004).
2. E. Haque, N. A. Khan, J. H. Park, and S. H. Jhung, Chem. Eur. J.
16, 1046 (2010).
3. Y. K. Hwang, J.-S. Chang, S.-E. Park, D. S. Kim, Y. U. Kwon, S. H.
Jhung, J.-S. Hwang, and M. S. Park, Angew. Chem. Int. Ed. 44, 557
(
2005).
24. S. H. Jhung, J. W. Yoon, Y. K. Hwang, and J.-S. Chang, Microporous
Mesoporous Mater. 89, 9 (2006).
48. O. Macias, J. Largo, C. Pesquera, C. Blanco, and F. González, Appl.
Catal. A: General 314, 23 (2006).
25. S. H. Jhung, J.-S. Chang, J. S. Hwang, and S.-E. Park, Microporous
Mesoporous Mater. 64, 33 (2003).
49. P. Wang, A. Lv, J. Hu, J. Xu, and G. Lu, Microporous Mesoporous
Mater. 152, 178 (2012).
Received: 19 September 2012. Accepted: 13 October 2012.
2
788
J. Nanosci. Nanotechnol. 13, 2782–2788, 2013