Synthesis of dimethyldichlorosilane by catalytic disproportionation of methyltrichlorosilane over a H2SO4 activated chinese bentonite

Article abstract of DOI:10.1080/10426507.2011.590167

Disproportionation of methyltrichlorosilane (MTS) to produce dimethyldichlorosilane (DMCS) was firstly carried out over a bentonite from Zhejiang province (China) after H₂SO₄ activation. The results demonstrated that the bentonite activated with 30 wt% H ₂SO₄ solution exhibited an excellent activity with 92% conversion of MTS and 41% yield of DMCS at 673 K under atmospheric pressure. The catalysts were characterized by inductively coupled plasma atomic emission spectroscopy (ICP-AES), X-ray powder diffraction (XRD) and N₂ absorption-desorption. The acidic sites of these bentonites were studied by in situ FTIR spectra of pyridine adsorption. It revealed that the coexistence of Lewis (L) and Bronsted (B) acidic sites facilitated the formation of DMCS and reaction temperature played important roles in the disproportionation reaction. Copyright Taylor & Francis Group, LLC.

Full text of DOI:10.1080/10426507.2011.590167

This article was downloaded by: [Nanyang Technological University]
On: 25 April 2015, At: 01:54
Publisher: Taylor & Francis
Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered
office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK
Phosphorus, Sulfur, and Silicon and the
Related Elements
Publication details, including instructions for authors and
subscription information:
http://www.tandfonline.com/loi/gpss20
Synthesis of Dimethyldichlorosilane
by Catalytic Disproportionation of
Methyltrichlorosilane Over A H SO
2
4
Activated Chinese Bentonite
a
a
a
a
a
Zhiyong Ao , Ning Zhang , Lijuan Jian , Qiong Fu , Fang Zhang
a
&
a
Chao Chen
Department of Chemistry , Nanchang University , Nanchang, P. R.
China
Published online: 14 Oct 2011.
To cite this article: Zhiyong Ao , Ning Zhang , Lijuan Jian , Qiong Fu , Fang Zhang & Chao Chen (2011)
Synthesis of Dimethyldichlorosilane by Catalytic Disproportionation of Methyltrichlorosilane Over A
H SO Activated Chinese Bentonite, Phosphorus, Sulfur, and Silicon and the Related Elements, 186:10,
2
4
2135-2144, DOI: 10.1080/10426507.2011.590167
To link to this article: http://dx.doi.org/10.1080/10426507.2011.590167
PLEASE SCROLL DOWN FOR ARTICLE
Taylor & Francis makes every effort to ensure the accuracy of all the information (the
“
Content”) contained in the publications on our platform. However, Taylor & Francis,
our agents, and our licensors make no representations or warranties whatsoever as to
the accuracy, completeness, or suitability for any purpose of the Content. Any opinions
and views expressed in this publication are the opinions and views of the authors,
and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content
should not be relied upon and should be independently verified with primary sources
of information. Taylor and Francis shall not be liable for any losses, actions, claims,
proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or
howsoever caused arising directly or indirectly in connection with, in relation to or arising
out of the use of the Content.
This article may be used for research, teaching, and private study purposes. Any
substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing,
systematic supply, or distribution in any form to anyone is expressly forbidden. Terms &

Conditions of access and use can be found at http://www.tandfonline.com/page/terms-
and-conditions

Phosphorus, Sulfur, and Silicon, 186:2135–2144, 2011
Copyright ꢀ
Taylor & Francis Group, LLC
C
ISSN: 1042-6507 print / 1563-5325 online
DOI: 10.1080/10426507.2011.590167
SYNTHESIS OF DIMETHYLDICHLOROSILANE
BY CATALYTIC DISPROPORTIONATION
OF METHYLTRICHLOROSILANE OVER A H SO
2
4
ACTIVATED CHINESE BENTONITE
Zhiyong Ao, Ning Zhang, Lijuan Jian, Qiong Fu, Fang Zhang,
and Chao Chen
Department of Chemistry, Nanchang University, Nanchang, P. R. China
GRAPHICAL ABSTRACT
Abstract Disproportionation of methyltrichlorosilane (MTS) to produce dimethyldichlorosi-
lane (DMCS) was firstly carried out over a bentonite from Zhejiang province (China) after
H2SO4 activation. The results demonstrated that the bentonite activated with 30 wt% H2SO4
solution exhibited an excellent activity with 92% conversion of MTS and 41% yield of DMCS
at 673 K under atmospheric pressure. The catalysts were characterized by inductively coupled
plasma atomic emission spectroscopy (ICP-AES), X-ray powder diffraction (XRD) and N2
Received 18 March 2011; accepted 14 May 2011.
This work was supported by the National Natural Science Foundation of China (No. 21062013 and
0562007), the Foundation of Educational Department of Jiangxi Province and the Graduate Innovation Founda-
2
tion of Jiangxi Province (No.YC09A032).
Address correspondence to Ning Zhang, Department of Chemistry, Nanchang University, Nanchang 330031,
P. R. China. E-mail: nzhang.ncu@163.com.
2
135

2
136
Z. AO ET AL.
absorption–desorption. The acidic sites of these bentonites were studied by in situ FTIR spectra
of pyridine adsorption. It revealed that the coexistence of Lewis (L) and Brønsted (B) acidic
sites facilitated the formation of DMCS and reaction temperature played important roles in the
disproportionation reaction.
Keywords Disproportionation; methyltrichlorosilane; dimethyldichlorosilane; bentonite; acid
activation
INTRODUCTION
Methyltrichlorosilane (MTS) is a main byproduct for preparing dimethyldichlorosi-
1
lane (DMCS). With the rapid development of the organosilicone industry; about 500,000
tons of MTS have been produced per year worldwide. As it is known, MTS is of low value
2
and detrimental to the environment. Therefore, it is necessary to find better ways to utilize
MTS. Recently, many studies have been performed on the utilization of MTS, such as
converting it to SiC,3 using it as a raw material to synthesize functional materials and
combusting it to pyrogenic silica.9 However, the consumption of MTS through the above
ways was limited by the demands of these products.
–6
7,8
,10
To make use of MTS more effectively, converting it to DMCS by a disproportionation
reaction (Scheme 1) or redistributing with rich-methyl chlorosilane, has recently been of
11–13
great interest.
This is owing to the relatively higher value and larger market for DMCS.
Generally, acid catalysts, such as AlCl3, Al2O3, zeolites, aluminosilicate, and organoalu-
1
4–17
minums,
are effective for these disproportionation and redistribution reactions. Among
these acid catalysts, AlCl3 has been investigated extensively because of its high efficiency
for DMCS. However, it also shows drawbacks that numerous solid wastes are produced
and high pressure is needed to prevent AlCl3 sublimation.
Scheme 1
In this study, we focus on an acid catalyst (bentonite), which has wide applications
because it is environmentally friendly, cheap, and exhibits high stability.18–20 However,
natural bentonite possesses a very low catalytic activity. To obtain the desired bentonite,
2
1–25
different modified methods have been applied.
Acid activation is an important process,
which could improve their acidic properties, surface areas, and porosities. Herein, H2SO4
was employed to active the raw bentonite, owing to its ability to form aqueous solutions of
high proton concentration. The effects of acid concentration and the reaction temperature
on catalytic behavior were investigated. To our knowledge, this is the first report in which
bentonite has been utilized to catalyze disproportionation of MTS.

SYNTHESIS OF DIMETHYLDICHLOROSILANE BY CATALYTIC DISPROPORTIONATION2137
RESULTS AND DISCUSSION
Catalyst Characterization
Figure 1 shows the X-ray powder diffraction (XRD) patterns of Raw-BN and acid
◦
◦
◦
◦
activated bentonites. The diffraction peaks at 2θ = 6.1 , 19.8 , 35 , and 61.9 were ascribed
26
◦
◦
◦
◦
◦
to bentonite, the peaks at 22.1 , 22.8 , and 29.5 to calcite, the peaks at 26.6 and 20.8
to quartz, and the peak at 27.6 to feldspar. Noticeably, the diffraction trace for Raw-BN
◦
27
◦
exhibited intense d (001) reflection (2θ = 6.1 , d = 14.40 Å). Subsequent to mild acid
treatment (concentrations in the range of 10–30 wt%), the d (001) reflection was much
broader and weaker, which demonstrated that the samples were less ordered than the parent
material. After being treated with H2SO4 solution of concentration exceeding 40 wt%,
the d (001) reflection vanished, indicating the complete collapse of the layer structure.
◦
◦
This was also confirmed by the disappearance of diffraction peaks at 2θ = 19.8 , 35 ,
◦
and 61.9 (Figure 1b). In comparison, the peaks of calcite gradually disappeared with the
2−
acid treatment, revealing the dissolution of (Ca, Mg)CO3 (Table 1). As presented in
2
−1
Table 2, Raw-BN had a surface area of 38 m ·g . When treated with 10, 20, and 30 wt%
2
−1
H2SO4 solution, the surface areas of samples increased to 341 m ·g , which was mainly
27
related to the gradual elimination of exchangeable cations filled within the interlayer. It
was consistent with that of the element analysis results (Table 1). With further stronger
activation, the surface areas of samples started decreasing, probably due to collapse of the
layer structure (Figure 1a) and uncompletely exchange of the cations.
The FTIR spectra of pyridine adsorption on the acid activated bentonites are presented
in Figure 2. For 10%H2SO4-BN, 20%H2SO4-BN, and 30%H2SO4-BN, a clear increase
−1
in the intensity of peak at 1544 cm reflected that new B acidic sites were created in
the samples. It could be explained that the exchangeable cations were initially replaced
28
by protons, followed by partial dissolution of tetrahedral and octahedral sheets. When
treatment condition became more severe, the reduction of B acidic sites might be due to the
Figure 1 Small-angle (a) and wide-angle (b) XRD patterns of acid activated bentonites. B: bentonite; C: calcite
(
Ca, Mg)CO3; F: feldspar, Q: quartz.

2
138
Z. AO ET AL.
Table 1 Chemical compositions (in mass%) of the raw and acid activated bentonites
Compound sample
Raw-BN
SiO2a
Al2O3
Fe2O3
MgO
CaO
Na2O
K2O
57.65
62.18
63.63
66.06
68.23
68.36
67.32
66.69
18.02
11.82
10.55
7.47
4.95
4.70
5.47
5.33
5.09
4.86
4.71
4.76
4.77
4.78
3.13
2.49
1.34
0.57
0.10
0.03
0.01
1.29
2.19
1.23
1.11
1.04
0.26
0.28
0.38
0.34
2.05
0.44
0.41
0.24
0.18
0.22
0.38
0.27
3.66
0.40
0.36
0.32
0.28
0.28
0.42
0.62
1
2
3
4
5
6
7
0%H2SO4-BN
0%H2SO4-BN
0%H2SO4-BN
0%H2SO4-BN
0%H2SO4-BN
0%H2SO4-BN
0%H2SO4-BN
5.99
6.77
aSiO2 content was calculated according to the contents of other compositions.
3
+
hydroxyl groups in octahedral Al sheets decreased intensively with the dissolution of Al
in the structure.29 And the diminution in the intensity of the peak at 1443 cm indicated
−1
that L acid sites gradually diminished, probably because of the gradual dissolution of metal
30
ions during acid treatment. Additionally, no significant peaks corresponding to acidic sites
absorption were observed in 30%H2SO4-SiO2, and the 30%H2SO4-Al2O3 only showed L
−1
acidic sites absorptions (1443 and 1613 cm ).
As is well known, progressive dehydration of bentonite may occur during heating,
with consequent transformation from octahedron Al to tetrahedron Al, resulting in B into L
acidic site transformation (Scheme 2).31,32 Figure 3 shows the spectra of pyridine adsorption
on the 30%H2SO4-BN pretreated at different temperatures. When elevating the pretreatment
temperatures, B acidic sites decreased by 58% while L acidic sites increased by 151% as
compared with Raw-BN. The decrease of B acidic sites was probably due to the gradual loss
33
of hydroxyl groups of Al(OH)Al in the structure, which was proved by the diminution in
−1
intensity of hydroxyl group absorption at 3650 cm (Figure 4). The increase of L acidic
sites could be ascribed to B into L acidic sites transformation (Scheme 2).
∗
Scheme 2 TOT structure: two tetrahedral Si atoms link to the same octahedral Al.

SYNTHESIS OF DIMETHYLDICHLOROSILANE BY CATALYTIC DISPROPORTIONATION2139
Table 2 Textural properties of samples treated with H2SO4 solutions with different concentrations
BET
Surface
area
BJH
Average pore
Weight ratioa
of liquid:
solid
Average pore
diameter
b
Area of
volume
2
−1 c
−1 d
d
Sample
d(001)
(m ·g
)
(mL·g
)
(nm)
Raw-BN
0
2059
1098
727
440
—
—
—
—
—
38
0.08
7.7
4.7
4.8
5.9
6.5
7.0
6.9
6.1
10
1
2
3
4
5
6
7
3
3
0%H2SO4-BN
0%H2SO4-BN
0%H2SO4-BN
0%H2SO4-BN
0%H2SO4-BN
0%H2SO4-BN
0%H2SO4-BN
0%H2SO4-Al2O3
0%H2SO4-SiO2
1.2
1.3
1.4
1.5
1.6
1.7
1.8
0.9
1.5
196
305
341
318
307
253
265
182
85
0.23
0.36
0.51
0.51
0.53
0.43
0.40
0.48
0.15
—
14
a
Volume ratio of liquid : solid was 3.
The integral area of d(001) diffraction peak.
The samples surface area were calculated using the Brunauer–Emmett–Teller (BET) method based on adsorp-
b
c
tion data in the partial pressure (P/P0) range of 0.05–0.35.
dThe average pore size was obtained from the adsorption data by the Barrett–Joyner–Halenda (BJH) method.
Catalytic Activities
Table 3 shows the catalytic behaviors of bentonite treated with H2SO4 solution
of different concentrations at 673 K. The conversion of MTS reached to the highest on
Figure 2 FTIR spectra of pyridine adsorption on different samples, followed by evacuation at 673 K: (a)
3
4
0%H2SO4-SiO2; (b) 30%H2SO4-Al2O3; (c) 10%H2SO4-BN; (d) 20%H2SO4-BN; (e) 30%H2SO4-BN; (f)
0%H2SO4-BN; (g) 50%H2SO4-BN; (h) 60%H2SO4-BN; and (i) 70%H2SO4-BN.

2
140
Z. AO ET AL.
Figure 3 FTIR spectra of pyridine adsorption on 30%H2SO4-BN pretreated at various temperatures with a N2
−1
rate of 35 mL·min , followed by evacuation at 473 K. Pretreatment temperatures: (a) 473 K; (b) 573 K; (c) 673
K; (d) 773 K; and (e) 873 K. spectra not to scale.
30%H2SO4-BN, which could be attributed to its largest surface areas (Table 2). The
selectivity to DMCS increased at first and then decreased with acid treatment, which
was in accordance with the changes of B acidic sites revealed in Figure 3. This suggested
that the B acidic sites played a positive role in the selectivity to DMCS.
Figure 5 presents the MTS conversion (A), DMCS selectivity (B), and DMCS yield
(C) over different catalysts at various temperatures. It can be seen that 30%H2SO4-SiO2
Figure 4 The OH stretching FTIR spectra of 30%H2SO4-BN at temperatures: (a) 313 K; (b) 373 K; (c) 473 K;
d) 573 K; (e) 673 K; (f) 773 K; (g) 873 K; and (h) 923 K. spectra not to scale.
(

SYNTHESIS OF DIMETHYLDICHLOROSILANE BY CATALYTIC DISPROPORTIONATION2141
Table 3 Catalytic activities of acid activated bentonites at 673 K
DMCS
Sample
MTS conversion (%)
Selectivity (%)
Yield (%)
Raw-BN
22
41
84
92
83
76
65
53
21
17
33
45
42
36
36
30
4.6
7
1
2
3
4
5
6
7
0%H2SO4-BN
0%H2SO4-BN
0%H2SO4-BN
0%H2SO4-BN
0%H2SO4-BN
0%H2SO4-BN
0%H2SO4-BN
23
41
35
27
23
16
Reaction conditions: 4 µL of MTS, 0.2 g of catalyst, N2 flow rate of 30 mL·min−1
.
Figure 5 Influence of temperatures on MTS conversion (A), DMCS selectivity (B), and DMCS yield (C); on
3
0%H2SO4-BN, 40%H2SO4-BN, 50%H2SO4-BN, 30%H2SO4-SiO2, and 30%H2SO4-Al2O3. Reaction condi-
−
1
tions: 4 µL of MTS, 0.2 g of catalyst, and N2 flow rate of 30 mL·min
.

2
142
Z. AO ET AL.
exhibited low activity for the disproportionation reaction because of the absence of acidic
34
sites, and the conversion of MTS could be ascribed to the thermal decomposition. For
0%H2SO4-BN, the conversion of MTS increased while the selectivity toward DMCS de-
3
creased when raising the reaction temperatures. The reason for the increment in conversion
of MTS could be ascribed to the increase of L acidic sites. The decrease of selectivity to
DMCS may be related to gradually disappearance of B acidic sites. It is noted that the con-
version of MTS decreased at 723 K, probably due to the reduction of surface area resulted
from collapse of layer structure.35 As is shown in Figure 5c, 30%H2SO4-BN exhibited an
excellent activity with 41% yield of DMCS at 673 K, which was higher as compared with
36
AlCl3 (4%) and 30%H2SO4-Al2O3 (24%) containing only L acidic sites. This suggested
that the coexistence of L and B acidic sites facilitated the formation of DMCS.
EXPERIMENTAL
Catalyst Preparation
The raw bentonite was provided by the Third Bentonite Chemicals Factory of Zhe-
jiang province (China), which consists of 57.65% SiO2; 18.02% Al2O3; 5.47% Fe2O3;
2.19% CaO; 3.13% MgO; 1.17% TiO2; 2.05% Na2O; and 3.66% K2O. The acid activated
bentonite was prepared by stirring a mixture of raw bentonite and H2SO4 solution at pre-
determined liquid–solid weight ratio at 368 K for 6 h (Table 2). After acid treatment, the
2−
solid product was filtered and washed with hot deionized water until free of SO4 ions
tested by BaCl2 solution), and the leachate was diluted to 50 mL and analyzed by ICP-
(
AES. Finally, the solid product was dried at 373 K for 12 h, and then calcined at 573 K in
air for 4 h. The mass concentrations of H2SO4 solution were 0%, 10%, 20%, 30%, 40%,
5
0%, 60%, and 70%, and the corresponding activated bentonites were marked as Raw-
BN, 10%H2SO4-BN, 20%H2SO4-BN, 30%H2SO4-BN, 40%H2SO4-BN, 50%H2SO4-BN,
0%H2SO4-BN, and 70%H2SO4-BN, respectively. For comparison, Al2O3 and SiO2 were
6
also treated with 30 wt% H2SO4 solution under the same conditions, and respectively
designated as 30%H2SO4-Al2O3 and 30%H2SO4-SiO2.
Physical and Chemical Characterization
The chemical compositions of activated bentonite were measured by ICP-AES using
an American PE Corporation’s Optima 5300 DV. XRD measurements were performed on
a Rigaku DMAX 2400 diffractometer with Cu Kα radiation (λ = 0.15418 nm, 40 kV/20
◦
mA) at the scanning step of 0.1 /s. N2 adsorption–desorption isotherms were measured
at 77 K using the Micromeritics ASAP 2020 adsorption analyzer. Prior to measurements,
the samples were degassed at 473 K in vacuum for 5 h. The specific surface area was
calculated using the BET equation and the pore size distribution was obtained from the
BJH model. The properties of acidic sites of these activated bentonites were characterized
by in situ FTIR spectra of pyridine adsorption, the spectra were collected on a Nicolet 5700
−
1
spectrometer (MCT/A detector) with an average of 32 runs and 4 cm definition in the
−1
range of 4000–650 cm . The thermal stability of hydroxyl groups were studied in situ by
FTIR. The sample was equilibrated at 923, 873, 773, 673, 573, 473, 373, and 313 K for 30
−1
min with a N2 flow rate of 35 mL·min .

SYNTHESIS OF DIMETHYLDICHLOROSILANE BY CATALYTIC DISPROPORTIONATION2143
Catalytic test
The catalytic reactions were conducted under atmospheric pressure with a fix-bed
reactor (U-shaped stainless steel tube, 4 mm i.d.). N2 was employed as carrier gas. The
catalyst was dried in situ at 423 K before reaction, and MTS (4 µL) was then injected
into the reactor containing 0.2 g of catalyst. The product and reactant were analyzed by an
on-line gas chromatograph instrument with a thermal conductor detector.
Conversion of MTS, selectivity and yield of DMCS were calculated as below:
ꢀ
ꢁ
moles of M1 consumed
moles of M1 fed
MTS conversion (% ) =
DMCS selectivity (% ) =
× 100
× 100
ꢀ
ꢁ
moles of M2 produced
moles of M1 consumed
DMCS yield (% ) = Conversion(%) × Selectivity(%)
All results were reproducible within experimental error.
CONCLUSION
Bentonite, as an environmentally friendly, cheap and high thermal stability acid
catalyst, was activated by H2SO4, and firstly applied in the disproportionation MTS to
produce DMCS. The outcomes displayed that the 30%H2SO4-BN exhibited an excellent
activity, with the MTS conversion of 92% and 45% selectivity to DMCS at 673 K under
atmospheric pressure. Further, insight into the catalytic results by ICP-AES, XRD, N2
adsorption–desorption and FTIR analyses revealed that L acidic sites and high temperature
promoted the conversions of MTS and DMCS, and the coexistence of L and B acidic sites
facilitated the yield to DMCS. Our future research will endeavor to obtain the mechanism
of this disproportionation reaction by modulating L and B acidic sites.
REFERENCES
1. Rochow, E. G.; J. Am. Chem. Soc. 1945, 67, 963-965.
2. Jiang, Y. Q.; Chen, W. G.; Liu, Y. J.; Yin, H. B.; Shen, Y. T.; Wang, A. L.; Yu, L. B.; Jiang, T. S.
Ind. Eng. Chem. Res. 2011, 50, 1893-1898.
3
. Zhang, W. G.; H u¨ ttinger, K. J. Chem. Vap. Deposition 2001, 7, 167-172.
4
. Zhang, W. G.; H u¨ ttinger, K. J. Chem. Vap. Deposition 2001, 7, 173-182.
5. Steckl, A. J.; Devrajan, J.; Tlali, S.; Jackson, H. E.; Tran, C.; Gorin, S. N.; Lvanova, L. M. Appl.
Phys. Lett. 1996, 69, 3824-3826.
6. Silenko, P. M.; Shlapak, A. N.; Tomila, T. V.; Bykov, A. I.; Kuz’menko, L. N.; Okun’, I. Y.;
Ragulya, A. V. Inorg. Mater. 2008, 44, 388-394.
7. Lin, D. Q.; Cheng, K.; Lu, X. X.; Sun, J. Synlett 2009, 18, 2961-2964.
8
. R a¨ ke, B.; Roesky, H. W.; I. Us o´ n; M u¨ ller, P. Angew. Chem. Int. Edn. 37, 1432-1433 (1998).
9. Rheinfelden, J. S.; Bruehl, L. L.; Klebe, H.; Schutte, D. U.S. Patent, 4258023, 1981.
1
1
1
1
1
1
0. Rohr, D. F.; Buddle, S. T.; Wilson, P. R.; Zumbrum, M. A. U.S. Patent, 5340560, 1994.
1. Kanner, B.; Lewis, K. M. U.S. Patent, 4599441, 1986.
2. Bluestien, B. A. U.S. Patent, 2717257, 1955.
3. Barry, A. J.; Gilkey, J. W. U.S. Patent, 2647912, 1953.
4. Lewis, K. M.; Chang, C. F. U.S. Patent, 4889838, 1989.
5. Hamilton, L. A., U.S. Pitman Patent, 3384652, 1968.

2
144
Z. AO ET AL.
1
1
1
1
6. Straussberger, H.; Streckel, W. U.S. Patent, 4155927, 1979.
7. Graf, W. P.; John Frey, V. U.S. Patent, 4158010, 1979.
8. Haffad, D.; Chambellan, A.; Lavalley, J. C. Catal. Lett. 1998, 54, 227-233.
9. Miranda, R.; R ´ı os, H.; Delgado, F.; Castro, M.; Cogord a´ n, A.; Salm o´ n, M. Appl. Catal. A:
General 2003, 244, 217-233.
2
2
0. Leyva, E.; L.I. L o´ pez; Moctezuma, E.; Lasa, H. Top. Catal. 2008, 49, 281-287.
1. Fernandes, C.; Catrinescu, C.; Castilho, P.; Russo, P. A.; Carrott, M. R.; Breen, C. Appl. Catal.
A: General 2007, 318, 108-120.
2
2
2
2
2. Massam, J.; Brown, D. R. Appl. Catal. A: General 1998, 172, 259-264.
3. Galeano, L. A.; Gil, A.; Vicente, M. A. Appl. Catal. B: Environ. 2010, 100, 271-281.
4. Herney-Ramirez, J.; Vicente, M. A.; Madeira, L. M. Appl. Catal. B: Environ. 2010, 98, 10-26.
5. Mart ´ı nez, T. L.M.; Dom ´ı nguez, M. I.; Sanabria, N.; Hern a´ ndez, W. Y.; Moreno, S.; Molina, R.;
Odriozola, J. A.; Centeno, M. A. Appl. Catal. A: General 2009, 364, 166-173.
6. Rinaldi, A.; Zhang, J.; Mizera, J.; Girgsdies, F.; Wang, N.; Hamid, S. B. A.; Schl o¨ gl, R.; Su, D.
S. Chem. Commun. 2008, 48, 6528-6530.
2
2
2
2
7. Gates, W. P.; Anderson, J. S.; Raven, M. D.; Churchman, G. J. Appl. Clay Sci. 2002, 20, 189-197.
8. Korichi, S.; Elias, A.; Mefti, A. Appl. Clay Sci. 2009, 42, 432-438.
9. Vukovi c´ , Z.; Milutonovi c´ , A.; Ro zˇ i c´ , L.; Rosi c´ , A.; Nedi c´ , Z.; Jovanovi c´ , D. Clays Clay Miner.
2006, 54, 697-702.
3
3
3
3
3
3
0. Pushpaletha, P.; Rugmini, S.; Lalithambika, M. Appl. Clay Sci. 2005, 30, 141-153.
1. Barzetti, T.; Selli, E.; Moscotti, D.; Forni, L. J. Chem. Soc., Faraday Trans. 1996, 92, 1401-1407.
2. Vaccari, A. Catal. Today 1998, 41, 53-71.
3. Bagshaw, S. A.; Cooney, R. P. Chem. Mater. 1993, 5, 1101-1109.
4. Ge, Y. B.; Gordon, M. S.; Battaglia, F.; Fox, R. O. J. Phys. Chem. A 2010, 114, 2384-2392.
´
5. Sanabria, N. R.; Avila, P.; Yates, M.; Rasmussen, S. B.; Molina, R.; Moreno, S. Appl. Clay Sci.
010, 47, 283-289.
6. Zemany, P. D.; Price, F. P. J. Am. Chem. Soc. 1948, 70, 4222-4226.
2
3