Catalytic decomposition of 2,3-dihydrobenzofuran to monomeric cyclic compounds over Pd/XCs2.5H0.5PW12O 40/OMC (ordered mesoporous carbon) (X = 10-30 wt.%) catalysts

Article abstract of DOI:10.1016/j.catcom.2014.02.009

A series of Pd/XCs_2.5H_0.5PW₁₂O ₄₀/OMC (ordered mesoporous carbon) (X = 10, 15, 20, 25, and 30 wt.%) catalysts with different Cs_2.5H_0.5PW₁₂O ₄₀ contents (X, wt%) were prepared by a sequential incipient wetness impregnation method for use in the catalytic decomposition of 2,3-dihydrobenzofuran to monomeric cyclic compounds. 2,3-Dihydrobenzofuran was used as a lignin model compound for representing β-5 linkage of lignin. Acidity of Pd/XCs_2.5H_0.5PW₁₂O₄₀/OMC catalysts served as an important factor determining the catalytic performance in the reaction. Conversion of 2,3-dihydrobenzofuran and total yield for main products (2-ethylphenol and ethylcyclohexane) increased with increasing acidity of Pd/XCs_2.5H_0.5PW₁₂O₄₀/OMC catalysts.

Full text of DOI:10.1016/j.catcom.2014.02.009

Catalysis Communications 49 (2014) 68–72
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Catalysis Communications
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Short Communication
Catalytic decomposition of 2,3-dihydrobenzofuran to monomeric
cyclic compounds over Pd/XCs2.5H0.5PW12O40/OMC
(ordered mesoporous carbon) (X = 10–30 wt.%) catalysts
⁎
Jeong Kwon Kim, Hai Woong Park, Ung Gi Hong, Yoon Jae Lee, Ji Hwan Song, In Kyu Song
School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Shinlim-dong, Kwanak-ku, Seoul 151-744, Republic of Korea
a r t i c l e i n f o
a b s t r a c t
Article history:
A series of Pd/XCs2.5H0.5PW12O40/OMC (ordered mesoporous carbon) (X = 10, 15, 20, 25, and 30 wt.%) catalysts
with different Cs2.5H0.5PW12O40 contents (X, wt%) were prepared by a sequential incipient wetness impregna-
tion method for use in the catalytic decomposition of 2,3-dihydrobenzofuran to monomeric cyclic compounds.
2,3-Dihydrobenzofuran was used as a lignin model compound for representing β-5 linkage of lignin. Acidity of
Pd/XCs2.5H0.5PW12O40/OMC catalysts served as an important factor determining the catalytic performance in
the reaction. Conversion of 2,3-dihydrobenzofuran and total yield for main products (2-ethylphenol and
ethylcyclohexane) increased with increasing acidity of Pd/XCs2.5H0.5PW12O40/OMC catalysts.
© 2014 Elsevier B.V. All rights reserved.
Received 13 January 2014
Received in revised form 7 February 2014
Accepted 9 February 2014
Available online 13 February 2014
Keywords:
Lignin
2,3-Dihydrobenzofuran
Decomposition
Pd/Cs2.5H0.5PW12O40/OMC
Acidity
1. Introduction
for selective decomposition of lignin model compounds containing
α-O-4, β-O-4, and β-5 bonds [5,10,11].
The depletion of fossil fuels and the growing concern about the
emission of carbon dioxide have forced many researchers to investigate
environmental and sustainable energy resources such as biomass [1]. In
particular, lignin has received much attention as a valuable biomass,
because it is renewable and does not compete with food resources [2].
Furthermore, lignin, which is an amorphous polymer comprising com-
plex aromatic structures, is regarded as a good source for production of
aromatics and high-value chemicals [3,4]. Therefore, decomposition of
lignin is an advantageous technology for obtaining valuable chemicals.
Catalysis has attracted significant attention as a key technology for
the selective conversion of lignin into useful chemicals [5,6]. Convention-
al pyrolysis process has been studied for the decomposition of lignin
[6–8]. Although pyrolysis shows considerable performance for decom-
position of lignin, it requires severe reaction conditions and produces
substantial amounts of undesired products such as gasses and char
[6,7]. It is known that noble metal catalysts supported on carbon (Pt/C,
Pd/C, and Rh/C) are efficient for selective decomposition of C\O bond
in lignin under mild conditions [5,8,9]. Acid catalysts such as mineral
acid, cesium exchanged heteropolyacid (CsXH3.0 − XPW12O40, X =
2.0–3.0), and zeolites have also shown considerable performance
It has been reported that acid strength of heteropolyacids (HPAs) is
stronger than that of conventional solid acids [11,12]. HPA salts with
Cs+, K+, and NH+4 cations have high surface area and porous structure
by forming a tertiary structure [12]. It is known that the surface acidity
of cation-exchanged HPAs is varied depending on cation content. For
example, surface acidity of CsxH3.0 − xPW12O40 shows a maximum
value when cesium content is 2.5 [11,12].
Due to the complex structure of lignin, studies on lignin decomposi-
tion have been simplified by employing lignin model compounds [5].
Therefore, various monomeric and dimeric chemical compounds con-
taining C\O bonds such as α-O-4, β-O-4, and β-5 bonds are used as lig-
nin model compounds, because C\O bonds are abundant linkage type in
lignin. Among various lignin model compounds, 2,3-dihydrobenzofuran
has been used as a lignin model compound for representing β-5 bond in
lignin [5,13,14].
In this work, ordered mesoporous carbon (OMC) was prepared by
a surfactant-templating method. In order to provide acid site to
OMC, Cs2.5H0.5PW12O40 was impregnated on OMC with a variation of
Cs2.5H0.5PW12O40 content (XCs2.5H0.5PW12O40/OMC, X = 10–30 wt.%).
Palladium catalysts supported on XCs2.5H0.5PW12O40/OMC (Pd/XCs2.5
H0.5PW12O40/OMC) were then prepared by an incipient wetness
impregnation method, and they were applied to the catalytic decom-
position of 2,3-dihydrobenzofuran to monomeric cyclic compounds.
2,3-Dihydrobenzofuran was chosen as a lignin model compound for
representing β-5 bond in lignin. In order to investigate the effect of
⁎
Corresponding author. Tel.: +82 2 880 9227; fax: +82 2 889 7415.
E-mail address: inksong@snu.ac.kr (I.K. Song).
http://dx.doi.org/10.1016/j.catcom.2014.02.009
1566-7367/© 2014 Elsevier B.V. All rights reserved.

J.K. Kim et al. / Catalysis Communications 49 (2014) 68–72
69
acidity on the catalytic performance of Pd/XCs2.5H0.5PW12O40/OMC
catalysts, correlations between catalytic performance and acidity of
Pd/XCs2.5H0.5PW12O40/OMC (X = 10–30 wt.%) catalysts were estab-
lished and discussed.
100 mA. Textural properties (surface area, pore volume, and average
pore size) of the catalysts were examined using an ASAP-2010 instru-
ment (Micromeritics). NH3-TPD measurement was carried out in
order to measure the acidity of the catalysts. Each catalyst (20 mg)
was charged into a tubular quartz reactor of the TPD apparatus. The cat-
alyst was preheated at 200 °C for 1 h under a flow of He (20 ml/min) to
remove any physisorbed organic molecules. Ammonia (20 ml/min) was
then pulsed into the reactor every minute at room temperature under a
flow of He (5 ml/min), until the acid sites were saturated with ammo-
nia. Physisorbed ammonia was removed by evacuating the catalyst
sample at 100 °C for 1 h. Furnace temperature was increased from
room temperature to 800 °C at a heating rate of 5 °C/min under a flow
of He (10 ml/min). The desorbed ammonia was detected using a GC-
MSD (Agilent, MSD-6890N GC).
2. Experimental
2.1. Catalyst preparation
Ordered mesoporous carbon (OMC) was prepared according to
method reported in the literature [15]. A known amount of H3PW12O40
(Sigma-Aldrich) was impregnated onto 0.5 g of OMC (XH3PW12O40
/
OMC, X = 10, 15, 20, 25, and 30 wt.%) by an incipient wetness impreg-
nation method, and it was dried overnight at 80 °C. A known amount
of cesium chloride (CsCl, Sigma-Aldrich) was dissolved in 10 ml of dis-
tilled water. 0.5 g of XH3PW12O40/OMC was then dispersed into the solu-
tion containing cesium chloride, and the mixture was stirred for 12 h.
After filtering and washing a solid product with distillated water, the
solid was dried overnight at 80 °C. The solid was finally calcined at
300 °C for 3 h to obtain XCs2.5H0.5PW12O40/OMC. 5 wt.% of palladium
was supported on XCs2.5H0.5PW12O40/OMC (X = 10, 15, 20, 25, and
30 wt.%) by an incipient wetness impregnation method. Palladium chlo-
ride (PdCl2, Sigma-Aldrich) was dissolved in 5 ml of distilled water, and
it was then introduced into the pores of XCs2.5H0.5PW12O40/OMC. The
supported catalyst was dried overnight at 80 °C and calcined at 300 °C
for 3 h. The supported catalyst was then reduced with a mixed stream
of hydrogen (2.5 ml/min) and nitrogen (47.5 ml/min) at 250 °C for 6 h
prior to the catalytic reaction.
2.3. Catalytic decomposition of 2,3-dihydrobenzofuran
Decomposition of 2,3-dihydrobenzofuran over Pd/XCs2.5H0.5PW12
O40/OMC catalysts was carried out in a stainless steel autoclave reactor
(25 ml) under hydrogen atmosphere. 9 ml of hexadecane (Sigma-
Aldrich, a solvent) and 0.05 g catalyst were charged into the reactor. 1
ml of 2,3-dihydrobenzofuran (Sigma-Aldrich) was then added into the
reactor. The catalytic reaction was performed at 250 °C and 30 atm
(H2) for 1 h with agitation speed of 250 rpm. Reaction products were an-
alyzed with a gas chromatograph (Younglin, YL6100 GC-FID) equipped
with DB-1 column and flame ionization detector. Conversion of 2,3-
dihydrobenzofuran and selectivity for main product (2-ethylphenol or
ethylcyclohexane) were calculated according to the following equations.
Yield for main product (2-ethylphenol or ethylcyclohexane) was calcu-
lated by multiplying the conversion of 2,3-dihydrobenzofuran and corre-
sponding product selectivity.
2.2. Catalysts characterization
Pore structure, pore size, and Cs2.5H0.5PW12O40 dispersion of the cat-
alysts were examined by HR-TEM (Jeol, JEM-3000F) analyses. Crystal-
line states of the catalyst were determined by XRD (D-MA2500-PC,
Rigaku) measurements using Cu-Kα radiation operated at 50 kV and
Conversion of 2; 3−dihydrobenzofuran
ð1Þ
moles of 2; 3‐dihydrobenzofuran reacted
¼
moles of 2; 3‐dihydrobenzofuran supplied
Fig. 1. TEM images of Pd/XCs2.5H0.5PW12O40/OMC (X = 10, 15, 20, 25, and 30 wt.%) catalysts.

70
J.K. Kim et al. / Catalysis Communications 49 (2014) 68–72
Pd/XCs2.5H0.5PW12O40/OMC catalysts were almost identical to those of
OMC. Pd/XCs2.5H0.5PW12O40/OMC catalysts exhibited an ordered
porous structure, indicating that the pore structure of OMC was still
maintained even after the loading of Cs2.5H0.5PW12O40 and palladium.
It should be noted that Pd/XCs2.5H0.5PW12O40/OMC (X = 10, 15, and
20 wt.%) catalysts retained no Cs2.5H0.5PW12O40 agglomerates, while
Pd/XCs2.5H0.5PW12O40/OMC (X = 25 and 30 wt.%) catalysts showed
Cs2.5H0.5PW12O40 agglomerates.
Fig. 2 shows the XRD patterns of OMC, Cs2.5H0.5PW12O40, and Pd/
XCs2.5H0.5PW12O40/OMC (X = 10, 15, 20, 25, and 30 wt.%) catalysts.
OMC showed no diffraction peaks due to its amorphous nature [15]. Dif-
fraction peaks for Cs2.5H0.5PW12O40 were not observed in the Pd/XCs2.5
H0.5PW12O40/OMC (X = 10, 15, and 20 wt.%) catalysts due to the fine
dispersion of Cs2.5H0.5PW12O40 onto OMC. However, Pd/XCs2.5H0.5PW12
O40/OMC (X = 25 and 30 wt.%) catalysts exhibited diffraction peaks
for Cs2.5H0.5PW12O40, and peak intensities increased with increasing
Cs2.5H0.5PW12O40 content. These results were well consistent with the
TEM results of Pd/XCs2.5H0.5PW12O40/OMC (Fig. 1). Successful impregna-
tion of palladium metal on XCs2.5H0.5PW12O40/OMC (X = 10-30 wt.%)
was also confirmed by XRD patterns (Fig. 2). Average palladium particle
size of the catalysts calculated by the Debye–Scherrer equation was in
the range of 8.1–8.6 nm, as listed in Table 1.
10
20
30
40
50
60
70
2 Theta (degree)
Textural properties of Pd/XCs2.5H0.5PW12O40/OMC (X = 10–30 wt.%)
catalysts were examined by nitrogen adsorption–desorption isotherm
measurements. All the samples showed type-IV isotherm with type-3
hysteresis loop (these are not shown here). This indicates that the
pore structure of OMC was still maintained even after the loading of
Cs2.5H0.5PW12O40 and palladium onto OMC, as also evidenced by TEM
images. Detailed textural properties of Pd/XCs2.5H0.5PW12O40/OMC
(X = 10–30 wt.%) catalysts are summarized in Table 1. Surface area
and pore volume of Pd/XCs2.5H0.5PW12O40/OMC (X = 10–30 wt.%) cat-
alysts monotonically decreased with increasing Cs2.5H0.5PW12O40 con-
tent. This was attributed to the formation of Cs2.5H0.5PW12O40
aggregates in the pore of OMC, resulting in the partial blockage of
OMC pore [16,17]. However, average pore diameter of Pd/XCs2.5H0.5
PW12O40/OMC (X = 10–30 wt.%) catalysts was almost identical, sug-
gesting that Pd/XCs2.5H0.5PW12O40/OMC catalysts still retained pore
characteristics of OMC.
Fig. 2. XRD patterns of OMC, Cs2.5H0.5PW12O40, and Pd/XCs2.5H0.5PW12O40/OMC (X = 10,
15, 20, 25, and 30 wt.%) catalysts.
Total selectivity for main products
ð2Þ
ð3Þ
Total moles of 2‐ethylphenol and ethylcyclohexane formed
¼
moles of 2; 3‐dihydrobenzofuran reacted
Total yield for main products
¼ ðConversion of 2; 3‐dihydrobenzofuranÞ
ꢀðTotal selectivity for main productsÞ
3. Results and discussion
Fig. 3 shows the NH3-TPD profiles of Pd/XCs2.5H0.5PW12O40/OMC
catalysts. Acidity of Pd/XCs2.5H0.5PW12O40/OMC catalysts determined
from NH3-TPD peak area is listed in Table 1. It is well known that Cs2.5
H0.5PW12O40 catalyst retains only Brönsted acid site [18]. Therefore,
3.1. Characterization of Pd/XCs2.5H0.5PW12O40/OMC
Fig. 1 shows the TEM images of Pd/XCs2.5H0.5PW12O40/OMC (X = 10,
15, 20, 25, and 30 wt.%) catalysts. Pore structure and pore size of
Table 1
Surface area, average pore diameter, pore volume, acidity, average palladium particle size, and catalytic performance of Pd/XCs2.5H0.5PW12O40/OMC in the decomposition of 2,3-
dihydrobenzofuran.
Catalyst
Pd/XCs2.5H0.5PW12O40/OMC
X = 10
X = 15
X = 20
X = 25
X = 30
SBET (m2/g)a
779.4
4.2
0.82
158
683.9
4.1
0.77
191
613.8
4.1
0.63
235
8.4
87.5
76.9
37.8
39.1
67.3
33.1
34.2
559.4
4.2
0.57
215
8.6
82.5
72.7
36.5
36.2
60.0
30.1
29.9
469.3
4.0
0.45
165
8.5
72.4
65.4
35.0
30.4
47.3
25.3
22.0
Average pore diameter (nm)b
Pore volume (cm3/g)c
Acidity (μmol-NH3/g)d
Particle size of Pde (nm)
Conversion of 2,3-dihydrobenzofuran(%)f
Total selectivity for main products (%)f
Ethylcyclohexane (%)
8.1
8.1
69.4
60.7
32.1
28.6
42.1
22.3
19.8
74.4
71.1
35.4
35.7
52.9
26.3
26.6
2-Ethylphenol (%)
Total yield for main products (%)f
Ehylcyclohexane (%)
2-Ethylphenol (%)
a
Calculated by BET (Barret–Joyner–Hallender) equation.
b
BJH (Barret–Joyner–Hallender) desorption average pore diameter.
BJH (Barret–Joyner–Hallender) desorption pore volume.
Calculated by peak area of NH3-TPD profile.
Calculated by the Debye–Scherrer equation.
Calculated according to Eqs. (1), (2), and (3).
c
d
e
f

J.K. Kim et al. / Catalysis Communications 49 (2014) 68–72
71
Pd/20Cs2.5H0.5PW12O40/OMC showed the largest acidity due to fine dis-
persion of Cs2.5H0.5PW12O40 onto OMC, as evidenced by TEM (Fig. 1)
and XRD (Fig. 2) results.
3.2. Catalytic performance in the decomposition of 2,3-dihydrobenzofuran
Fig. 4 shows the scheme for cleavage of β-5 bond in 2,3-dihydro-
benzofuran. According to the literature [19], 2,3-dihydrobenzofuran is
converted to octahydrobenzofuran through hydrogenation. Octahydro-
benzofuran is then converted to ethylcyclohexanol as an intermediate,
and it is further convert to ethylcyclohexane. 2-Ethylphenol is also pro-
duced by the cleavage of dihydrofuran ring in 2,3-dihydrobenzofuran
[13]. In our catalytic reaction, 2-ethylphenol and ethylcyclohexane
were mainly produced by the decomposition of 2,3-dihydrobenzofuran
over Pd/XCs2.5H0.5PW12O40/OMC. Small amounts of light hydrocarbons
(C2–C8) and alcohols were produced as by-products in the reaction.
Catalytic performance of Pd/XCs2.5H0.5PW12O40/OMC in the decom-
position of 2,3-dihydrobenzofuran performed at 250 °C and 30 bar
for 1 h is listed in Table 1. It was observed that the conversion
of 2,3-dihydrobenzofuran and total selectivity for main products
over Pd/XCs2.5H0.5PW12O40/OMC (X = 10–30 wt.%) showed volcano-
shaped trends with respect to Cs2.5H0.5PW12O40 content within the
range of 69.4–87.5% and 60.7–76.9%, respectively. The same trend
was also observed for total yield for main products (42.1–67.3%) with
respect to Cs2.5H0.5PW12O40 content. Among the catalysts tested,
Pd/20Cs2.5H0.5PW12O40/OMC catalyst showed the best catalytic perfor-
mance in terms of conversion of 2,3-dihydrobenzofuran (87.5%), total
selectivity for main products (76.9%), and total yield for main products
(67.3%).
0
100
200
300
400
500
600
700
800
Temperature (oC)
Fig. 3. NH3-TPD profiles of Pd/XCs2.5H0.5PW12O40/OMC (X = 10, 15, 20, 25, and 30 wt.%)
catalysts.
the acidity of Pd/XCs2.5H0.5PW12O40/OMC catalysts measured by
NH3-TPD represents the amount of Brönsted acid sites provided by
Cs2.5H0.5PW12O40. It is noteworthy that the acidity of the catalysts
showed a volcano-shaped trend with respect to Cs2.5H0.5PW12O40 con-
tent within the range of 158–235 μmol-NH3/g. Among the catalysts,
Fig. 4. Scheme for cleavage of β-5 bond in 2,3-dihydrobenzofuran.
100
90
80
70
60
50
90
80
70
60
50
40
140
160
180
200
220
240
Acidity of Pd/XCs2.5H0.5PW12O40/OMC (µmol-NH3/g)
Fig. 5. Correlations of acidity of Pd/XCs2.5H0.5PW12O40/OMC catalysts with conversion of 2,3-dihydrobenzofuran and with total yield for main products at 250 °C after 1 h-reaction.

72
J.K. Kim et al. / Catalysis Communications 49 (2014) 68–72
Fig. 5 shows the correlations of acidity of Pd/XCs2.5H0.5PW12O40
/
Acknowledgments
OMC catalysts with the conversion of 2,3-dihydrobenzofuran and with
total yield for main products at 250 °C after 1 h-reaction. Acidity and
catalytic performance data were taken from Table 1. Conversion of
2,3-dihydrobenzofuran and total yield for main products increased
with increasing acidity of the catalysts. Among the catalysts tested,
Pd/20Cs2.5H0.5PW12O40/OMC catalyst with the largest acidity showed
the highest conversion of 2,3-dihydrobenzofuran and the highest total
yield for main products. Therefore, it is concluded that the acidity of
Pd/XCs2.5H0.5PW12O40/OMC catalysts served as an important factor de-
termining the catalytic performance in the decomposition of 2,3-
dihydrobenzofuran.
This work was supported by the National Research Foundation
of Korea Grant funded by the Korean Government (MEST) (NRF-
2012M1A2A2671739).
References
[1] P. Mckendry, Bioresour. Technol. 83 (2002) 47–54.
[2] J.H. Clark, J. Chem. Technol. Biotechnol. 82 (2007) 603–609.
[3] H.L. Jairo, G.G. Wolfgang, J. Polym. Environ. 10 (2002) 39–48.
[4] J.J. Bozell, Clean 36 (2008) 641–647.
[5] J. Zakeski, P.C.A. Bruijnincx, A.L. Jongerius, B.M. Weckhuysen, Chem. Rev. 110 (2010)
3552–3599.
[6] M. Saidi, F. Samimi, D. Karimipourfard, T. Nimmanwudipong, B.C. Gates, M.R.
Rahimpour, Energy Environ. Sci. 7 (2014) 103–129.
[7] Q. Bu, H. Lei, A.H. Zacher, L. Wang, S. Ren, J. Liang, Y. Wei, Y. Liu, J. Tang, Q. Zhang, R.
Ruan, Bioresour. Technol. 124 (2012) 470–477.
[8] M. Kleinert, T. Barth, Energy Fuels 22 (2008) 1371–1379.
[9] N. Yan, C. Zhao, P.J. Dyson, C. Wang, L.-T. Liu, Y. Kou, ChemSusChem 1 (2008)
626–629.
[10] A. Cyr, F. Chilts, P. Jeanson, A. Martel, L. Brossard, J. Lessard, H. Ménard, Can. J. Chem.
78 (2000) 307–315.
[11] H.W. Park, J.K. Kim, U.G. Hong, Y.J. Lee, J.H. Song, I.K. Song, Catal. Surv. Jpn. 17 (2013)
119–131.
[12] M. Misono, Catal. Rev. Sci. Eng. 29 (1987) 269–321.
[13] Y. Romero, F. Richard, Y. Renème, S. Brunet, Appl. Catal. A Gen. 353 (2009) 46–53.
[14] E. Dorrestijn, L.J.J. Laarhoven, I.W.C.E. Arends, P. Mulder, J. Anal. Appl. Pyrolysis 54
(2000) 153–192.
[15] C.C. Ting, H.Y. Wu, S. Vetrivel, D. Saikia, Y.C. Pan, G.T.K. Fey, H.M. Kao, Microporous
Mesoporous Mater. 128 (2010) 1–11.
[16] R. Gao, H. Chen, Y. Le, W.L. Dai, K. Fan, Appl. Catal., A 352 (2009) 61–65.
[17] S. Park, J.H. Choi, T.J. Kim, Y.M. Chung, S.H. Oh, I.K. Song, J. Mol. Catal. A Chem. 353
(2012) 37–43.
4. Conclusions
A series of Cs2.5H0.5PW12O40 supported on OMC (XCs2.5H0.5PW12O40
/
OMC) were prepared with a variation of Cs2.5H0.5PW12O40 content
(X = 10–30 wt.%). Palladium catalysts supported on XCs2.5H0.5PW12
O40/OMC were then prepared by an incipient wetness impregnation
method, and they applied to the catalytic decomposition of 2,3-
dihydrobenzofuran. 2,3-Dihydrobenzofuran was used as lignin model
compounds for representing β-5 linkage of lignin. The conversion of
2,3-dihydrobenzofuran and total yield for main products (2-ethylphenol
and ethylcyclohexane) increased with increasing acidity of Pd/XCs2.5
H0.5PW12O40/OMC catalysts. Among the catalysts tested, Pd/20Cs2.5H0.5
PW12O40/OMC with the largest acidity showed the highest conversion
of 2,3-dihydrobenzofuran (87.5%) and the highest total yield for main
products (67.3%). Thus, acidity of the catalysts played an important
role in determining the catalytic performance in the decomposition of
2,3-dihydrobenzofuran over Pd/XCs2.5H0.5PW12O40/OMC catalysts.
[18] T. Okuhara, N. Mizuno, M. Misono, Adv. Catal. 41 (1996) 113–242.
[19] C. Liu, Z. Shao, Z. Xiao, C.T. Williams, C. Liang, Energy Fuels 26 (2012) 4205–4211.