J. Chem. Sci. Vol. 126, No. 1, January 2014, pp. 111–115. ꢀc Indian Academy of Sciences.
Cobalt(II) supported on ethylenediamine-functionalized nanocellulose as
an efficient catalyst for room temperature aerobic oxidation of alcohols
∗
AHMAD SHAABANI , SAJJAD KESHIPOUR, MONA HAMIDZAD
and MOZHDEH SEYYEDHAMZEH
Faculty of Chemistry, Shahid Beheshti University, G. C., P. O. Box 19396-4716, Tehran, Iran
e-mail: a-shaabani@sbu.ac.ir
MS received 18 June 2013; revised 22 September 2013; accepted 25 September 2013
Abstract. Ethylenediamine-functionalized nanocellulose complexed with cobalt(II) was found to be a highly
efficient heterogeneous catalyst for the room temperature aerobic oxidation of various types of primary and
secondary benzylic alcohols into their corresponding aldehydes and ketones, respectively. The catalyst showed
no significant loss of efficiency after five reaction cycles.
Keywords. Heterogeneous catalyst; aerobic oxidation; alcohols; modified-nanocellulose; cobalt.
1
. Introduction
deal of attention in both green chemistry and organic
synthesis.
Selective oxidation of alcohols to their corresponding
carbonyl compounds is of significant importance in
organic chemistry, both for fundamental research and
industrial manufacturing. This transformation is tra-
ditionally carried out using stoichiometric quantities
of inorganic oxidants, which are relatively expensive,
highly toxic and environmentally polluting.1 There-
fore, introducing green, selective and efficient aero-
bic oxidation systems for alcohols are of prime impor-
tance for both economic and environmental reasons.
Numerous aerobic catalytic homogeneous oxidation
Many different materials have been employed to sup-
port in heterogeneous catalytic systems, such as meso-
7,8
9–11
12,13
porous silica, activated carbon,
(bio)polymer
14
and biomass. With increasing concern about environ-
mental pollution, the direction of science and techno-
logy has been shifting more towards eco-friendly, na-
tural product resources and reusable catalysts. Thus,
natural biopolymers are attractive candidates for such
solid support catalysts. Among several reusable and
heterogeneous supports, cellulose as an inexpensive
and biodegradable natural polymer is one of the useful
examples, that can be easily separated, reused and is not
–3
approaches are reported for alcohols using O as oxi-
2
15,16
dant, which are inexpensive and produce water as the
contaminated by the products.
Cellulose whiskers,
4,5
sole product. Homogeneous catalysts increase acti-
vity, since alcohols and catalysts coexist in the same
phase. However, homogeneous catalysts have draw-
backs such as tedious catalyst separation and recycling,
and pollution of the product with catalyst. Immobi-
lization of homogeneous catalyst on solid supports not
only simplifies reaction procedure and increases stabi-
lity and recyclability of the catalyst, but it is also an
important technique to render homogeneous systems
a name that refers to the needle-like structure of the
crystallite, was separated from various sources such
as wheat straw and tunic in. This nanostructured fibre
has very high aspect ratio which gives exceptional
17
characteristics to the nanofibre.
Numerous examples of cellulose-supported organic
transformations are reported in the literature.1
Herein, we wish to highlight a new catalytic system
including Co(II) supported on ethylenediamine-
functionalized nanostructured cellulose (Co(II)-
EDANC) as an efficient and reusable catalyst for aero-
bic oxidation of various benzylalcohols. Our group’s
contributions to this field are linked to our broader
interest in the development of aerobic oxidation reac-
8–20
1–3,6
heterogeneous.
Therefore, the development of new
heterogeneous catalytic systems based on reusable and
biodegradable solid support for the aerobic oxidation of
alcohols under ambient conditions should attract a great
21–23
21,24–28
tions
and cellulose-supported catalysts.
We
focus particularly on Co(II)-promoted oxidative trans-
formations of alkyl arenes, alcohols, and silyl ethers.
∗
For correspondence
111