ISSN 0036ꢀ0244, Russian Journal of Physical Chemistry A, 2011, Vol. 85, No. 7, pp. 1155–1161. © Pleiades Publishing, Ltd., 2011.
Original Russian Text © A.V. Mekhaev, A.V. Pestov, L.S. Molochnikov, E.G. Kovaleva, M.G. Pervova, Yu.G. Yaltuk, I.A. Grigor’ev, I.A. Kirilyuk, 2011, published in Zhurnal
Fizicheskoi Khimii, 2011, Vol. 85, No. 7, pp. 1261–1267.
STRUCTURE OF MATTER
AND QUANTUM CHEMISTRY
Structure and Characteristics
of Chitosan CobaltꢀContaining Hybrid Systems,
the Catalysts of Olefine Oxidation
A. V. Mekhaeva, A. V. Pestova, L. S. Molochnikovb, E. G. Kovalevab, M. G. Pervovaa,
Yu. G. Yaltuka, I. A. Grigor’evc, and I. A. Kirilyukc
a Institute of Organic Synthesis, Ural Branch, Russian Academy of Sciences, Yekaterinburg, 620219 Russia
b Ural State Forest Engineering University, Yekaterinburg, 620032 Russia
c Novosibirsk Institute of Organic Chemistry, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090 Russia
eꢀmail: yatluk@ios.uran.ru
Received June 7, 2010
Abstract—Cobaltꢀcontaining hybrid organo–inorganic materials based on the chitosan–SiO2, chitosan–
Al2O3, and chitosan–cellulose systems were obtained. The surface structure and processes that occur during
the formation of metalꢀcontaining materials, the catalytic properties of which were studied in the oxidation
reactions of alkene, were investigated by EPR spectroscopy using a stable pHꢀsensitive nitroxyl radical,
4ꢀdimethylaminoꢀ2ꢀethylꢀ5,5ꢀdimethylꢀ2ꢀ(pyridinꢀ4ꢀyl)ꢀ2,5ꢀdihydroꢀ1Hꢀimidazoleꢀ1ꢀoxyl, as the adsorbed
probe molecules.
Keywords: chitosan cobaltꢀcontaining hybrid systems, catalysis, olefine oxidation, probe molecules.
DOI: 10.1134/S0036024411070211
INTRODUCTION
EXPERIMENTAL SECTION
Materials and Instruments
The use of hybrid organo–inorganic materials as
supports is a new area in the development of new
We used microcrystalline cellulose (MCC) with an
metalꢀcontaining catalytic materials. It allows us to ash content of 0.16% and a humidity of 1.1% proꢀ
duced by JSC Polyex; Basic aluminum oxide; BSꢀ50
silicon oxide; and chitosan produced by JSC Sonat
(Moscow), for which the degree of deacetylation
obtain supports with specific surfaces that are capable
of retaining the metallic component of a catalytic sysꢀ
tem more strongly. Chitosan, polyꢀDꢀ ꢀglucosamine,
β
1
(DD) as determined by H NMR spectroscopy was
is a commercially available amino polymer that is a
perfect complexing agent, due to the strong donor
properties of both the amino and hydroxyl groups [1].
Chitosan is thus widely used in obtaining various cataꢀ
lytic materials, including those containing Au0 that are
used in the hydroamination of alkenes [2]; Pd0, used
for the reduction of ketones [3]; the Pd0–Ni0 bimetalꢀ
lic system, used for carbonylation [4]; Os(VIII), used
for hydroxylation [5]; Co2+, used for hydration [6];
and Cu2+, used for the oxidation of catecholamines
[7]. Metalꢀcontaining hybrid organo–inorganic
materials can also be used as antibacterial composites
[8], as sorbents of proteins [9], and as pervaporation
membranes [10]. This work is devoted to investigating
0.84, the molecular weight as determined by viscosimꢀ
etry was 250 kDa [11], and the ash content was 0.19%.
The hybrid chitosan–support (SiO2, Al2O3, cellulose)
systems were obtained by depositing chitosan on the
support surface. To measure pH near the surface of the
samples, we used an aqueous solution of stable
pHꢀsensitive nitroxyl radical (NR), 4ꢀdimethylꢀ
aminoꢀ2ꢀethylꢀ5,5ꢀdimethylꢀ2ꢀ(pyridinꢀ4ꢀyl)ꢀ2,5ꢀ
dihydroꢀ1Hꢀimidazoleꢀ1ꢀoxyl [12], with a concentraꢀ
tion of 10–4 mol/l. The EPR spectra of the nitroxyl
radical solutions were registered using an ADANI
PSꢀ110X EPR spectrometer (Belarus) in the 3 cm
wavelength range at room temperature and under
optimum conditions of microwave power and ampliꢀ
tude of the magnetic field modulation.
Citrateꢀphosphate (pH 3.5–7.8) and citrateꢀsalt
(pH 1.6–4.8) buffer solutions were used to vary the pH
within the NR sensitive range of 2.5–7.5; the ionic
the surface of hybrid catalytic support (SiO2, Al2O3
,
cellulose)–chitosan–Co2+ systems by means of EPR
spectroscopy, and to assesing their catalytic properties
in the reaction of alkene oxidation.
strength of the solutions,
I, was maintained at
0.1 (KCl). Determination of pH in the pores and near
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