1070-4272/05/7805-0753C2005 Pleiades Publishing, Inc.
Russian Journal of Applied Chemistry, Vol. 78, No. 5, 2005, pp. 753!757. Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 5,
2005, pp. 767!771.
Original Russian Text Copyright + 2005 by Skorokhodova, Kobotaeva, Sirotkina.
Reactivity of Copper Nanopowders in a Model Reaction
of Isopropylbenzene Oxidation
T. S. Skorokhodova, N. S. Kobotaeva, and E. E. Sirotkina
Institute of Petrochemistry, Siberian Division, Russian Academy of Sciences, Tomsk, Russia
Received July 27, 2004; in final form, December 2004
Abstract-The reactivity of copper nanopowders produced by an electric explosion of a conductor or
mechanochemically was studied. Oxidation of isopropylbenzene was used as a model reaction. The depen-
dence of the oxygen uptake rate on the specific surface area of a copper nanopowder and on the method used
for its production is discussed. A possible mechanism of isopropylbenzene oxidation in the presence of
copper nanopowders is suggested.
The intermediate position occupied by nanopar-
ticles in passing from a bulk metal to a separate atom
predetermines the deviation of their physicochemical
properties from those of bulk metals, on the one hand,
and from the properties of isolated atoms, on the
other. This deviation is manifested in electronic, mag-
netic, optical, and other properties of nanoparticles
with a characteristic size of several tens of nanometers
to several nanometers . Numerous summarizing
papers concerning methods for preparation and stabili-
zation of nanoparticles and their optical and other
properties have already appeared, whereas studies
of chemical transformations involving nanoparticles
are only in their initial stage .
It is known  that nanosize powders (NPs) of
metals show an increased reactivity, compared to
compact metals. For example, reactions that do not
occur in the presence of some metals or require severe
conditions readily proceed in the presence of metal
nanopowders. In particular, synthesis of complex
compounds (phthalocyanines and tetraphenylpor-
phyrins) with the use of copper and indium NP [4, 5]
is performed under milder conditions (room tempera-
ture and atmospheric pressure) than the conventional
synthesis with metal salts. Use of metal NPs as cata-
lysts for oxidation of organic compounds is known.
It was shown in  that the uptake of oxygen in oxi-
dation of isopropylbenzene (IPB) in the presence of
NPs of copper and cobalt proceeds at a sufficiently
high rate even at 30oC without any initiator.
In this study we examined the reactivity of copper
NP, obtained by an electric explosion of a conductor
(EEC) or mechanochemically, in a model reaction of
As objects of study served copper NP obtained by
an electric explosion of a conductor in the atmosphere
of nitrogen, argon, and xenon, as well as copper NP
produced mechanochemically on an AGO-2 installa-
tion in the presence of organic and inorganic addi-
The additives were used to raise the specific
surface area of the mechanochemically produced NP
. Copper nanopowders were produced by mechani-
cal treatment (MT) in AGO-2 planetary-centrifugal
high-energy-intensity mills in the presence of an or-
ganic surfactant (2,2,3,3,4,4,5,5-octafluorovaleramide)
in an amount of 10% for 10 (Cu I), 20 (Cu II), and
30 min (Cu III). Copper powders were also prepared
by mechanical treatment in the presence of 15 wt %
was washed out with ethanol after MT)
on an AGO-2 installation for 10 (Cu 1), 20 (Cu 2),
and 30 min (Cu 3). The physicochemical parameters
and the preparation conditions of copper NPs used
in this study are listed in Table 1.
IPB was oxidized on a gasometric installation .
A 0.7-M portion of IPB and 0.12 wt % copper NP
were placed in the reactor. The reaction was per-
formed at 30 and 60oC without initiator (azodiiso-
butyronitrile, AIBN). The reaction was stopped at the
minimum rate of oxygen uptake (10315 ml min
which is determined by the scale factor of the buret in
the gasometric installation. In some cases, repeated
oxidation was performed 24 h after the end of the first
Electric-explosion Cu NPs were obtained at the Institute of
High-Current Electronics, Siberian Division, Russian Acad-
emy of Sciences, Tomsk; mechanochemical Cu NPs, at the
Institute of Solid-State Chemistry and Mechanochemistry,
Siberian Division, Russian Academy of Sciences, Novosibirsk.