A recyclable polymer anchored copper(II) catalyst for oxidation reaction of olefins and alcohols with tert-butylhydroperoxide in aqueous medium

Article abstract of DOI:10.1016/j.inoche.2012.07.002

A new reusable polymer anchored Cu(II) complex was synthesized which can acts as an efficient heterogeneous catalyst for oxidation of olefins and alcohols with tert-butylhydroperoxide (TBHP) in aqueous medium. The present catalyst well oxidized styrene and other olefins to their allylic products and alcohols were converted to their corresponding aldehydes in good-to-moderate yields. This catalyst can be easily recovered by filtration and recycled without significant loss of its catalytic performances.

Full text of DOI:10.1016/j.inoche.2012.07.002

Inorganic Chemistry Communications 24 (2012) 170–176
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Inorganic Chemistry Communications
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A recyclable polymer anchored copper(II) catalyst for oxidation reaction of olefins
and alcohols with tert-butylhydroperoxide in aqueous medium
S.M. Islam ⁎, Anupam Singha Roy, Paramita Mondal, Sumantra Paul, Noor Salam
Department of Chemistry, University of Kalyani, Kalyani, Nadia, 741235, W.B., India
a r t i c l e i n f o
a b s t r a c t
Article history:
A new reusable polymer anchored Cu(II) complex was synthesized which can acts as an efficient heteroge-
neous catalyst for oxidation of olefins and alcohols with tert-butylhydroperoxide (TBHP) in aqueous medium.
The present catalyst well oxidized styrene and other olefins to their allylic products and alcohols were
converted to their corresponding aldehydes in good-to-moderate yields. This catalyst can be easily recovered
by filtration and recycled without significant loss of its catalytic performances.
Received 11 May 2012
Accepted 2 July 2012
Available online 13 July 2012
Keywords:
©
2012 Elsevier B.V. All rights reserved.
Olefin oxidation
Alcohol oxidation
Polymer anchored
Copper complex
tert-Butylhydroperoxide
Aqueous medium
The use of transition metal complexes as catalysts for the oxida-
tion reactions has been a subject of great interest [1,2], oxidation
being carried out by using several oxidants, such as oxygen, hydrogen
peroxide, and tert-butylhydroperoxide (TBHP) [3,4]. Many soluble
metal complexes have been found to be active catalysts in the oxida-
tion reaction during the last few decades. Recently, soluble com-
pounds of early transition metals such as rhenium [5], vanadium
water has been paid extraordinary attention. Apart from being a
chemically interesting solvent, water provides a cheap (both in cost
price and in ecotax) alternative for organic solvents, making it envi-
ronmentally and economically interesting as well. However, for
organic synthetic chemists, who are trained to put compounds in solu-
tion and frequently approach organic reactions from a “like-need like
perspective”, it is less important, because water is traditionally not a
popular choice of solvent. It is commonly accepted that a mixture of
water and one or more nonpolar organic reactants will usually have
low reaction rates and low yields of the desired products [21]. K. Barry
Sharpless and his colleagues report [22] that the above assumption
does not hold for a variety of organic reactions (ene reactions, nucleo-
philic substitutions, Claisen rearrangements and Diels-Alder reactions)
in the ‘on water’ approach that they have pioneered [21]. Phase transfer
catalysis is becoming an interestingly important technique in organic
synthesis. But there is one limitation in this method that many phase
transfer catalysts promote stable emulsion which renders work-up dif-
ficult. Regen introduced the new concept of triphase catalysis, in which
the catalyst and each of a pair of reagents are located in separated phase
[23,24]. The major advantage of triphase catalysis over phase transfer
catalysis is that the catalyst can be removed from the reaction mixture
by simple filtration. So, based on the above two concepts, we tried to
synthesize a new polymer anchored metal complex which can catalyze
the organic reactions in aqueous medium without any phase transfer
catalyst.
[6], manganese [7] and molybdenum [8] have been used for alkene
oxidations. Good activities and selectivities have been pointed out
as the main advantages of homogeneous catalysts. However, some in-
dustrial problems such as corrosion, deposition on reactor wall, diffi-
culty in recovery and separation of the catalyst from the reaction
mixtures are associated with these homogeneous catalysts. These dis-
advantages were minimized if homogeneous complexes were
immobilized onto insoluble solid supports. Amorphous silica [9],
modified MCM-41 [10] and alumina [11] have been used for immobi-
lization of homogeneous compounds and applied them as catalysts
for alkene oxidation. Nowadays, polystyrene is one of the most widely
employed solid supports for the synthesis of functionalized polymer an-
chored catalysts [12–15]. Immobilization of active homogeneous metal
complexes on polymeric supports has evolved as a promising strategy
for combining the advantages of both homogeneous and heterogeneous
catalysts [16–19].
In the chemical processes, traditional organic solvents are used in
large quantities, which has led to various environmental and health
concerns. As part of green chemistry efforts, a variety of cleaner sol-
vents have been used as replacements [20]. As an alternative solvent,
Here, we have developed polymer anchored Cu(II) catalyst and
characterized it. Catalytic performances were investigated in liquid
phase oxidation of olefins in water. The influences of various reaction
parameters on the conversion of styrene have been studied in order
to optimize the reaction conditions. Furthermore, this catalyst can
⁎
Corresponding author. Tel.: +91 33 2582 8750; fax: +91 33 2582 8282.
E-mail address: manir65@rediffmail.com (S.M. Islam).
1387-7003/$ – see front matter © 2012 Elsevier B.V. All rights reserved.
doi:10.1016/j.inoche.2012.07.002

S.M. Islam et al. / Inorganic Chemistry Communications 24 (2012) 170–176
171
catalyze the epoxidation of cyclooctene and oxidation of aromatic al-
cohols. The results illustrated that the heterogeneous copper catalyst
was effective for the oxidation reaction with a variety of organic com-
pounds using TBHP as oxidant in water and found to be easily recov-
erable, recyclable up to five times.
After complexation of copper metal on polymer supported ligand, ther-
mal stability of the immobilized complex is improved. Polymer supported
Cu(II) complex decomposed at 390–410 °C. So, thermogravimetric study
suggests that the polymer anchored copper catalyst degraded at consid-
erably higher temperature.
The polymer supported copper complex was prepared by the
complexation of copper salts with polymer anchored ligand (3)
The electronic spectrum of the immobilized copper catalyst has
been recorded in the diffuse reflectance mode. The UV–vis spectra
provided further evidence for the presence of metal on the polymer
support. The spectrum of the copper catalyst exhibits few spectral
bands (Fig. S2 in supporting information). The spectral band at
275 nm is due to intra ligand charge transfer and the bands at
375 nm and at 446 nm are due to LMCT. The band at 446 nm indi-
cates the phenolic oxygen to copper charge transfer [29]. In the com-
plex, the band around 674 nm is due to d–d transition which
corresponds to the square-planar geometry [30,31].
In the first stage of the investigation for the catalysis, we tested the
oxidation reactions [32] of olefins in water using this catalyst and in
all the cases allylic oxidation products are obtained. In order to opti-
mize the reaction conditions, oxidation of styrene with polymer an-
chored Cu(II) catalyst was taken as probe reaction. In this case
styrene selectively converted to benzaldehyde. Effects of various oxi-
dants on the conversion of styrene and selectivity of benzaldehyde
using polymer anchored Cu(II) catalyst was summarized in Table 1.
(
Scheme 1) [25]. Amino polystyrene was synthesized and character-
ized in earlier studies [26]. After that it was reacted with di-bromo
ethane under refluxing condition using K CO as base and produced
2
3
ligand (2). Under refluxing conditions, functionalized polymer
supported ligand (2) reacted with o-aminophenol successfully to
yield the corresponding polymer supported ligand (3) as shown in
Scheme 1. Finally a solution of copper chloride was added to the li-
gand (3) and dark brown polymer supported copper catalyst was
obtained. Due to insolubilities of the polymer anchored Cu(II) catalyst
in all common organic solvents, the characterization of the catalyst
was done on the basis of infrared spectroscopy, diffuse reflectance
spectra of solid, thermogravimetric analysis and by using scanning
electron microscope. The metal content in the catalyst determined
by atomic absorption spectroscopy suggests 2.23 wt.% Cu in the het-
erogeneous catalyst.
The modes of attachment of copper metal onto the support were
confirmed by comparison of the FT-IR spectral bands of the copper cat-
alyst over the polymer in various steps of its synthesis. Polymer an-
We investigated the ability of various oxidants like TBHP, H
2 2
O ,
NaIO , PhIO and KHSO in styrene oxidation reaction (Table 1, Entries
4
5
−
1
chored ligand (2) exhibited a broad band around 3400 cm
which is
2–6). As shown in Table 1, TBHP is the best oxidant among the five
assigned to N-H (secondary amine) stretching frequency. The intensity
of this band increased in polymer anchored ligand (3) and also there
oxidants that are used in catalytic oxidation reaction in the present
study (Table 1, Entry 2). Oxidants like H
ly less efficient than TBHP as is evident from the percentage of con-
version of styrene (Table 1, Entries 3–5). The use of KHSO is not
2 2 4
O , PhIO and NaIO are clear-
−
1
was a band at 1381 cm which is assigned to phenolic C\O stretching
frequency. This C\O stretching band is shifted to lower frequency re-
5
−
1
gion and appeared at 1367 cm
in copper complex which indicates
favored because a buffer is needed (Table 1, Entry 6). The effect of
temperature on the performance of the catalyst was also studied at
three different temperatures, viz. 50, 60 and 70 °C at fixed amount
of styrene (5 mmol), TBHP (10 mmol), Cu(II) catalyst (0.030 g) in
5 mL water (Table 1, Entries 2 and 7–8 ). A maximum of 96% conver-
sion was achieved on carrying out the reaction at 60 °C. At 50 °C, the
conversion was low. At 70 °C, the initial conversion of styrene was
high than at 60 °C but when the reaction continues the conversion
of styrene was almost same with conversion at 60 °C. Therefore
60 °C was the optimum temperature and all catalytic oxidation reac-
tions of olefins were carried out at this temperature. The activity of
the polymer anchored Cu(II) catalyst in the oxidation of styrene was
also evaluated using three different molar ratios of styrene to TBHP
(Table 1, Entries 2 and 9–10). The conversion of styrene was in-
creased from 68% to 96% on increasing the styrene: TBHP ratio from
1:1 to 1:2. On further increasing this ratio to 1:3, the conversion
was hardly affected. From the results, it was suggested that 1:2 ratio
that copper metal is attached with the polymer anchored ligand through
−
1
the phenolic oxygen. On the other hand, the band at 3400 cm region
−
1
is shifted to lower frequency region and appeared at 3365 cm in the
complex. Polymer anchored Cu(II) catalyst exhibited important IR
−
1
−1
peaks at 540 cm
3
(ν Cu–N ), 622 cm
(v Cu–O) [27] and at
−
1
54 cm (v Cu–Cl) [28]. The scanning electron micrographs of polymer
anchored ligand (Fig. 1A) and supported copper catalyst (Fig. 1B) clearly
show the morphological change which occurred after complexation and
suggest the loading of copper metal on the surface of polymer. Energy
dispersive spectroscopy analysis of X-rays (EDAX) data for polymer an-
chored ligand and supported copper catalyst are given in Fig. 2 (A and
B). The EDAX data also confirm the attachment of copper metal on the
surface of the polymer matrix. Thermal stability of the complex was in-
vestigated using TGA at a heating rate of 10 °C/ min in air over a temper-
ature range of 30–600 °C (Fig. S1 in supporting information). Polymer
supported ligand decomposed in the temperature range 310–340 °C.
Scheme 1. Synthesis of polymer anchored copper(II) catalyst.

172
S.M. Islam et al. / Inorganic Chemistry Communications 24 (2012) 170–176
Fig. 1. FE SEM image of polymer anchored ligand (3) (1A) and polymer anchored Cu(II) catalyst (1B).
of styrene to TBHP is sufficient for the good conversion of styrene. In
order to show the effect of polymer anchored copper complex in the
oxidation reaction, a blank experiment (Table 1, Entry 11) in the pres-
ence of oxidant and using the same experimental conditions in the
absence of the catalyst was also investigated in the oxidation of sty-
rene. The obtained results showed that TBHP has poor ability to oxi-
dize the styrene.
catalyst and the results are shown in Table 2. This catalyst efficiently
converts olefins to their corresponding allylic products with TBHP in
aqueous medium. In the oxidation of cyclohexene, allylic products
2-cyclohexene-1-one and 2-cyclohexene-1-ol were obtained. Substituted
styrene produced selectively corresponding aldehydes. Acetophenone
was detected in the oxidation of α-methyl styrene as major product.
trans-Stilbene was also oxidized by this heterogeneous catalyst in high
yields. trans-Stilbene gives benzaldehyde as major product with benzil.
This catalytic system shows a good activity in the case of α-pinene. In
The above optimized reaction conditions could be applied to the
oxidation reactions of other olefins by polymer anchored Cu(II)
Fig. 2. EDAX data of polymer anchored ligand (3) (A) and polymer anchored Cu(II) catalyst (B).

S.M. Islam et al. / Inorganic Chemistry Communications 24 (2012) 170–176
173
Table 1
Table 3
Oxidation of styrene using different oxidants catalyzed by polymer anchored Cu(II)
catalyst.
Oxidation of styrene with TBHP catalyzed by a variety of catalysts.
a
Catalyst
Reaction condition
Water, 60 °C, 8 h
Conversion (%)
96
Reference
Entry Oxidant Temperature Conversion (%)b Selectivity(%)b
TOF
(
−1)c
h
Polymer anchored
Cu(II) catalyst
This study
Benzaldehyde Styrene
oxide
CuCl16Pc-MCM-41
ACN, 40 °C, 8 h
1,2-Dichloroethane,
47
23.7
28
29
[
Cu(2,2-bipy)(H2btec)]α
1
2
3
4
5
6
7
8
9
1
1
None
TBHP
60 °C
60 °C
60 °C
60 °C
60 °C
60 °C
50 °C
70 °C
60 °C
60 °C
60 °C
0
96
41
17
35
29
57
96
68
97
8
0
88
83
59
43
54
86
75
82
90
74
0
9
–
75 °C, 24 h
57.14
24.40
10.12
20.83
17.26
33.93
57.14
40.48
57.74
-
HMS-Cu-I
Cu L(μ1,1-N
1,1,1-N )]/ silica
ACN, 60 °C, 12 h
ACN, 60 °C, 24 h
89.4
88
30
31
H
2
O
2
15
36
55
43
13
21
17
9
[
2
3 3
)(μ1,3-N )
PhIO
NaIO
(μ
3
4
KHSO
TBHP
TBHP
TBHP
TBHP
TBHP
5
compared to others oxidants. Experiments were also carried out to
determine the effects of substrate to oxidant molar ratios on conver-
sion. For these experiments, cyclooctene and catalyst amounts were
held constant in water at 60 °C while the relative amounts of TBHP
were varied. As shown in Fig. 3, the conversion increases with TBHP
concentration and 1: 2 molar ratio of cyclooctene to TBHP was opti-
mal for the epoxidation reaction. Mechanistic pathway for the forma-
tion of epoxide can be explained by the similar type mechanism [37].
Here, peroxide replaced chloride from the metal complex and formed
peroxy linked copper complex. This peroxy linked copper complex
reacts with alkenes and formed an active intermediate. Then peroxide
attacked the active metal site and released epoxide.
d
e
f
0
1
25
a
Reaction conditions: catalyst (0.03 g, 1.05×10−2 mmol), styrene (5 mmol), water
(
5 mL), oxidant (10 mmol), time (8 h).
b
Determined by GC.
c
Turn over frequency (TOF): moles of substrate converted/mol of Cu/h. Loading of
Cu=0.035 mol%.
d
mmol ratio of styrene and TBHP=1:1.
mmol ratio of styrene and TBHP=1:3.
Reaction carried out without catalyst.
e
f
the oxidation of α-pinene, the major products were verbenone and
verbenol.
Several excellent catalysts for the oxidation of alcohols to the
corresponding aldehydes or ketones have been reported; most of
them required organic solvents and addition of base, which violate
the requirements of the “green chemistry”. Water is the most ideal
solvent because it is not only a green solvent but also can avoid the
hazards associated with the use of oxidizable organic solvents.
Base-free systems are also highly desired in that the presence of
base probably leads to the unwanted by-products. In line with the re-
quirements of “green chemistry”, we chose water as a reaction medi-
um to conduct the oxidation of alcohols in the absence of base.
We examined the catalytic activity of the polymer anchored Cu(II)
catalyst for the oxidation of benzyl alcohol by varying the various re-
action conditions. The effect of the amount of TBHP on the oxidation
of benzyl alcohol into benzaldehyde was studied and the results are
shown in Table 5. The percent conversion of benzyl alcohol into benz-
aldehyde is dependent upon TBHP up to a considerable amount. The
amount of TBHP was varied in terms of benzyl alcohol to TBHP
molar ratios. Benzyl alcohol to TBHP molar ratio of 1:1 resulted in
61% conversion when the amount of catalyst was 0.050 g, tempera-
ture was 50 °C and reaction time was 6 h. When benzyl alcohol to
TBHP molar ratio was raised to 1:2, the conversion was increased to
Further we have compared the activity of the polymer anchored
copper(II) catalyst in the oxidation reaction with the other reported
catalysts [33–36] (Table 3). The results show that our catalyst is supe-
rior to the reported catalysts in terms of reaction time, reaction tem-
perature, and conversion and in the present system; the reaction is
conducted in environmental friendly water.
Besides the above catalytic studies, we have also investigated the
epoxidation reaction of cyclooctene using polymer anchored copper
catalyst. Thus the epoxidation of cyclooctene catalyzed by polymer
anchored copper catalyst was first optimized and the results are sum-
marized in Table 4. The catalyst is very effective for the epoxidation of
cyclooctene in water with TBHP as the oxidant. The oxidation of
cyclooctene proceeded smoothly at 60 °C yielding to 92% conversion
within 8 h with 10 mmol of TBHP. The corresponding diol was
formed as a by-product. Among the screening of various solvents, it
appears that water is the best choice as compared to the others be-
cause it is polar and has high dielectric constant. We investigated
4
the ability of various oxidants like TBHP, NaIO , PhIO and NaOCl
(
Table 4, Entries 1–4). Among them TBHP was more effective
9
5% under all other similar conditions. However, the conversion was
found almost constant when benzyl alcohol to TBHP molar ratio was
further increased up to 1:3. Therefore 1:2 molar ratio of benzyl alco-
hol and TBHP was found to be optimum. The results for the oxidation
of benzyl alcohol in the presence of different amounts of catalyst were
Table 2
Olefins oxidation using TBHP catalyzed by polymer anchored Cu(II) catalyst.
a
Conversion(%)b Product (selectivity %)
Entry Substrate
TOF
−1)
(
h
Table 4
1
Cyclohexene
83
2-Cyclohexene-1-one (64)
-cyclohexene-1-ol (29)
Cyclohexene epoxide (7)
Benzaldehyde (78)
Benzil (16) trans-Stilbene oxide (6)
Verbenol (32) Verbenone (55) 28.57
49.40
Effect of various oxidants and solvents on epoxidation of cyclooctene using polymer
anchored Cu(II) catalyst.
2
a
2
3
4
5
6
trans-Stilbene
α-Pinene
67
48
39.88
Conversion (%)b
TOF (h−1
)
Entry
Oxidant
TBHP
Solvent
Temperature (°C)
1
2
3
4
5
6
7
8
9
H
H
H
H
2
2
2
2
O
O
O
O
60
60
60
60
60
60
60
50
40
92
49
27
34
56
65
45
78
43
54.76
29.17
16.07
20.24
33.33
38.69
26.79
46.43
25.59
α-pinene oxide (13)
NaIO
PhIO
4
4-Methylstyrene 84
4-Methyl benzaldehyde (84)
-Methylstyrene epoxide (16)
4-Chloro benzaldehyde (86)
-Chlorostyrene epoxide (14)
4-Nitro benzaldehyde (83)
-Nitro styrene oxide (17)
Acetophenone (100)
50.00
50.59
48.81
47.02
4
NaOCl
TBHP
TBHP
TBHP
TBHP
TBHP
4-Chlorostyrene
4-Nitrostyrene
85
82
Toluene
MeOH
CH Cl
2 2
O
O
4
4
H
H
2
7
α-Methyl styrene 79
2
a
Reaction conditions: catalyst (0.03 g, 1.05×10−2 mmol), substrate (5 mmol),
a
Reaction conditions: catalyst (0.03 g, 1.05×10−2 mmol), cyclooctene (5 mmol),
water (5 mL), TBHP (10 mmol), time (8 h).
solvent (5 mL), oxidant (10 mmol), time (8 h).
b
b
Determined by GC.
Determined by GC.

174
S.M. Islam et al. / Inorganic Chemistry Communications 24 (2012) 170–176
100
100
1
00
9
0
0
80
60
40
20
0
8
90
70
80
70
60
60
50
40
30
TBHP (mmol)
2
5
1
1
.5
0
5
Conversion of benzyl alcohol
Selectivity of benzaldehyde
20
0
2
4
6
8
10
12
14
16
50
0.08
0.02
0.03
0.04
0.05
0.06
0.07
Time (h)
Amount of catalyst (g)
Fig. 3. Influence of the amount of TBHP on epoxidation of cyclooctene. Reaction condition:
cyclooctene]=5 mmol, TBHP (10 mmol), water (10 ml), temperature (60 °C).
[
Fig. 4. Effect of amount of catalyst on oxidation reaction of benzyl alcohol catalyzed by
polymer anchored Cu(II) catalyst. Reaction condition: [benzyl alcohol]=5 mmol, TBHP
(10 mmol), water (10 ml), temperature (50 °C).
presented in Fig. 4. All the tests were conducted with 5 mmol sub-
strate, 10 mmol TBHP and at 50 °C in 5 mL water under base free con-
dition. 0.02 g polymer anchored catalyst afforded a conversion of 27%
within 6 h. No by-products such as benzoic acid were detected under
this reaction conditions. When the amount of the catalyst increased
up to 0.040 g, the conversion had an apparent increase and a 78% con-
version was achieved. But in this condition, a little amount of benzoic
acid was detected. A further increase in catalyst amount up to 0.05 g
led to an increase in the conversion (95%). However, when the cata-
lyst amount continuously increased up to 0.060 g and 0.070 g, the
conversion remains almost constant but the selectivity of benzalde-
hyde reduces. These findings indicate that the oxidation of benzyl al-
cohol is highly dependent on the amount of the solid catalyst. The
influence of temperature on the oxidation of benzyl alcohol was in-
vestigated by performing the reaction at a temperature range from
4
0 to 60 °C with all other parameters fixed. The results are given in
Table 5
a
Table 5 which reveals that the conversion is dependent on tempera-
ture. 54%, 95% and 96% conversion was recorded corresponding to
4
perature. At lower temperature, the conversion of benzyl alcohol into
benzaldehyde was considerably decreased.
In order to study the further catalytic activity of the catalyst for the
oxidation of aromatic alcohols, a series of benzylic alcohols were
used. Substituted benzyl alcohols are also oxidized to corresponding
aldehydes. In all above cases trace amount of acids were observed.
On the otherhand, 1-phenyl ethanol is selectively converted to
acetophenone on oxidation with this catalyst.
For any supported catalyst, it is important to know its ease of sep-
aration and possible reuse. For the recycling study, oxidation reac-
tions of styrene, cyclooctene and benzyl alcohol were performed
maintaining the above reaction conditions using the recovered cata-
lyst. Each time after completion of the reaction catalyst was recovered
by simple filtration, washed thoroughly with acetone, dried under
vacuum and reused under the same reaction conditions as for the ini-
tial run. The recycling efficiency of the catalyst up to five successive
runs is shown in Fig. 5. From the results, it is seen that the catalyst
retained its high catalytic activity in these five repeating cycles.
To check the leaching of metal into the solution during the reac-
tion, styrene oxidation reaction was carried out under the optimum
reaction conditions. The reaction is stopped after the reaction pro-
ceeds 6 h. The separated filtrate is allowed to react for another 4 h
under the same reaction conditions, but no further increment in con-
version is observed in gas chromatographic analyses. The UV–vis
spectroscopy was also used to determine the stability of these hetero-
geneous catalysts. The UV–vis spectra of the reaction solution, at the
first run, do not show any absorption peaks characteristic of copper
metal, indicating that the leaching of metal does not take place during
the course of the oxidation reaction. These results suggest that this
catalyst is heterogeneous in nature.
Oxidation of aromatic alcohols with TBHP catalyzed polymer anchored Cu(II) catalyst.
Entry Aromatic alcohol
Conversion
Product selectivity (%)b
TOF
0, 50 and 60 °C. Therefore, 50 °C was selected as the optimum tem-
b
−
(%)
(h
1
)
1c
Benzyl alcohol
Benzyl alcohol
Benzyl alcohol
Benzyl alcohol
Benzyl alcohol
61
95
96
54
96
84
Benzaldehyde (92)
Benzoic acid (8)
Benzaldehyde (96)
Benzoic acid (4)
Benzaldehyde (71)
Benzoic acid (29)
Benzaldehyde (87)
Benzoic acid (13)
Benzaldehyde (75)
Benzoic acid (25)
29.05
45.24
45.71
25.71
45.71
2d
3e
4f
5g
6
4-Methoxybenzyl
alcohol
4-Methoxy benzaldehyde 40.00
(84)
4
-Methoxy benzoic acid
(16)
7
4-Methylbenzyl
alcohol
83
4-Methyl benzaldehyde
(88)
39.52
4
-Methyl benzoic acid
12)
4-Nitro benzaldehyde (87) 38.09
-Nitro benzoic acid (13)
(
8
9
4-Nitrobenzyl alcohol 80
4
4-Chlorobenzyl
alcohol
89
4-Chloro benzaldehyde
(88)
42.38
4
-Chloro benzoic acid (12)
4-Cyno benzaldehyde (89) 41.43
-Cyno benzoic acid (11)
Acetophenone (100)
10
4-Cynobenzyl alcohol 87
1-Phenyl ethanol 74
4
11
35.24
a
Reaction condition: aromatic alcohol (5 mmol), TBHP (10 mmol), water (5 mL),
−
2
catalyst (50 mg, 1.75×10
mmol), temperature (50 °C), time (6 h).
b
Determined by GC.
Benzyl alcohol:H
Benzyl alcohol:H
Benzyl alcohol:H
Temperature (40 °C).
Temperature (60 °C).
c
2
O
2
=1:1.
d
e
f
2
O
2
=1:2, temperature (50 °C).
O =1:3.
2 2
g

S.M. Islam et al. / Inorganic Chemistry Communications 24 (2012) 170–176
175
epoxidation of cyclooctene
alcohol oxidation of styrene
oxidation of benzyl
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Polymer anchored copper complex has been prepared and used
for the catalytic oxidation of olefins and aromatic alcohols with
TBHP in aqueous medium. This catalyst shows good catalytic activi-
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idation products are obtained in aqueous medium. The procedure in
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Acknowledgments
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25] Preparation of polymer anchored ligand (3): To functionalize the amino polystyrene
with 2-aminophenol, amino polystyrene (2 g) was treated with 1, 2-dibromo ethane
MI acknowledges Department of Science and Technology (DST),
Council of Scientific and Industrial Research (CSIR) and University
Grant Commission (UGC), New Delhi, India for funding. ASR acknowl-
edges CSIR, New Delhi, for providing his senior research fellowship.
We gratefully acknowledge DST, New Delhi, for a grant under the
PURSE program to the University of Kalyani.
2 3
(0.6 mL) in 20 mL acetone containing K CO (0.96 g) under refluxing condition for
24 h. The pale yellow beads (2) thus obtained were washed with water followed
by acetone and dried in vacuum. Then dried beads (2 g) were reacted with
2-aminophenol (1 g) in 10 mL toluene and refluxed for 24 h. The yellow colored
polymer anchored ligand was washed with toluene followed by methanol and
dried under vacuum.Preparation of polymer anchored copper(II) catalyst: The func-
tionalized polymer ligand (1.0 g) was kept in contact with ethanol (10 mL) for
Appendix A. Supplementary data
2
30 min. Then ethanolic solution (10 mL) of CuCl (1%, w/v) was added to the
above suspension with constant stirring and refluxed on an oil bath for 24 h. After
cooling to room temperature, the reaction mixture was filtered, washed with etha-
nol and dried under vacuum.
Supplementary data to this article can be found online at http://
dx.doi.org/10.1016/j.inoche.2012.07.002.
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out in a two-necked round bottom flask fitted with a water condenser and placed
in an oil bath at different temperatures under vigorous stirring for a certain peri-
od of time. Substrates (5 mmol) were taken in water (5 mL) for different sets of
reactions together with catalyst in which 10 mmol of TBHP (70% in aq.) was
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2 ∞
btec)(bipy)] : a novel metal organic framework
(
8