CHINESE JOURNAL OF CATALYSIS
Volume 33, Issue 5, 2012
Online English edition of the Chinese language journal
Cite this article as: Chin. J. Catal., 2012, 33: 771–776.
ARTICLE
Catalytic Selective Oxidation of 4-Chlorotoluene by
Bi-MCM-41
1
2,
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ZHAO Junli , QIAN Guang *, LI Fengyun , ZHU Jie , JI Shengfu , LI Lei
1
School of Petrochemical Engineering, Changzhou University, Changzhou 213000, Jiangsu, China
College of Biology and Chemical Engineering, Jiaxing University, Jiaxing 314001, Zhengjiang, China
State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China
2
3
Abstract: A series of bismuth incorporated MCM-41 mesoporous samples were synthesized and characterized by inductive coupled plasma
emission spectrometer (ICP), X-ray diffraction, N adsorption/desorption, transmission electron microscopy, and UV-Vis spectroscopy.
These samples catalyzed the selective oxidation of 4-chlorotoluene efficiently even on a large scale with H as oxidant in acetonitrile. No
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O
bismuth was detected by ICP in the condensed reaction mother liquid, and the recycle test proved the catalyst was stable.
Key words: Bi-MCM-41; 4-chlorotoluene; oxidation; 4-chlorobenzaldehyde
4
-Chlorobenzaldehyde is an important intermediate used in
system is highly desired. Mesoporous materials, due to their
the synthesis of dyes, optical brighteners, agricultural chemi-
cals, and pharmaceuticals. Traditionally, 4-chlorobenzalde-
hyde is synthesized on a large scale by the acid hydrolysis of
chlorobenzal chloride, but this is a heavily polluting process
high surface area, well defined regular pore shape, narrow pore
size distribution, large pore volume, and tunable pore size in
the range of 1.6–20 nm have attracted much attention [14,15].
Bismuth is a well known component of mixed oxide catalysts
for gas phase oxidation [16,17]. In our early research, bismuth
atoms were introduced into the framework of MCM-41, and it
was shown that Bi-MCM-41 can catalyze the selective oxida-
tion of cyclohexane efficiently [18,19]. In this paper, a series
of Bi-MCM-41 were prepared and their catalytic activity in
the selective oxidation of 4-chlorotoluene was studied. The
purpose is to investigate the catalytic oxidation reaction and
develop a practical highly effective green catalytic system.
[
1–4]. As compared with the traditional method, the selective
oxidation of 4-chlorotoluene to 4-chlorobenzaldehyde is an
environmentally benign process because of the green, simpli-
fied operation, and short synthesis route. However, compared
to the abundant research on toluene oxidation [5–9], there are
few reports on this important process. Merga et al. [10] stud-
3
–
ied the oxidation of benzyl radicals by Fe(CN)6 and the cor-
responding possible mechanism. Singh et al. [11] reported that
vanadium silicate molecular sieves can catalyze the oxidation
of 4-chlorotoluene to 4-chlorobenzaldehyde effectively. It is
well-known that a Co/Mn/Br catalyst is a highly efficient
catalyst for the oxidation of toluene to benzoic acid [12], and
Hu et al. [13] found the catalyst is also effective for the selec-
tive oxidation of 4-chlorotoluene.
1 Experimental
1.1 Catalyst preparation
The synthesis procedure was carried out as follows. Cetyl
pyridine bromide (CPB, AR, Aldrich) deionized water, hy-
Although some research have been done on the selective
oxidation of 4-chlorotoluene and some interesting results were
obtained, there are many problems remaining, such as the
separation and reuse of the catalyst, and low conversion and
selectivity. The development of an efficient and green catalyst
o
drochloric acid, and bismuth nitrate were mixed at 50 C and
stirred for 30 min. Tetraethyl orthosilicate (TEOS, AR, Al-
drich) was added to the above mixture with vigorous stirring to
obtain a gel mixture. The molar composition of the gel was
Received 20 November 2011. Accepted 23 December 2011.
*
Corresponding author. Tel: +86-573-83648264; E-mail: qjiayun@163.com
This work was supported by the National Science Natural Foundation of China (20903047).
Copyright © 2012, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier BV. All rights reserved.
DOI: 10.1016/S1872-2067(11)60367-7