ISSN 1070-4272, Russian Journal of Applied Chemistry, 2007, Vol. 80, No. 1, pp. 159!161. + Pleiades Publishing, Ltd., 2006.
Original Russian Text + K.Yu. Murinov, T.V. Romanko, A.R. Kuramshina, N.N. Kabal’nova, Yu.I. Murinov, 2007, published in Zhurnal Prikladnoi
Khimii, 2007, Vol. 80, No. 1, pp. 159!161.
Oxidative Degradation of Chitosan under the Action
of Hydrogen Peroxide
K. Yu. Murinov, T. V. Romanko, A. R. Kuramshina,
N. N. Kabal’nova, and Yu. I. Murinov
Institute of Organic Chemistry, Ufa Scientific Center, Russian Academy of Sciences,
Ufa, Bashkortostan, Russia
Received May 25, 2006
Abstract-The reaction of chitosan with hydrogen peroxide in homogeneous medium and the influence of
iron(II) sulfate, copper(II) chloride, and disodium ethylenediaminetetraacetate on oxidative degradation
of chitosan were studied by the rheology method.
Materials based on chitosan (CS) with various
molecular weights are widely used in medicine [1, 2].
For production of chitosan oligomers, hydrogen per-
oxide can be used,  and the oxidation is accom-
panied by visible chemiluminescence .
Here we studied the influence of variable-valence
metal ions on oxidative degradation of chitosan under
the action of hydrogen peroxide by the rheology
In the experiments we used chitosan of Far-Eastern
RIG Production Association, TU (Technical Specifica-
tions) 6-09-05-397!75}. Milled CS (particle size less
than 0.6 mm) was treated with 1 N HCl four times for
3 h at room temperature until the supernatant became
colorless. The precipitate was filtered off and kept for
1.5 h in 2 N NaOH. Then, the precipitate was washed
with distilled water to neutral reaction and ash free
CS was dried at room temperature to constant weight.
The molecular weight (MW) of CS was (1.5!2.0)
; moisture content, 11%; and degree of deacetyla-
tion, 74.5% . Elemental composition (%): C 44.0,
H 7.5, N 7.9, O 42.6, and ash traces.
The rheological characteristics of hydrochloric acid
solutions of CS were studied in the temperature range
273!333 K at pH 4.5 on a modified Rheotest-2.1 vis-
cometer equipped with a special accessory with a
cylinder!cylinder working unit. The thermodynamic
characteristics of the solutions were evaluated from
the viscosity determined at a shear rate D = 1200 s
The experimental error was 3%.
The dependence of the viscosity of CS solutions on
the shear rate is shown in Fig. 1. As seen, at [CS] =
M (recalculated to elementary unit), its
aqueous solutions acidified to pH 4.5 behave as non-
Newtonian fluids, for which a decrease in the vis-
cosity is observed throughout the studied range of
the shear rate. On addition of hydrogen peroxide to
a CS solution in the temperature range 273!333 K,
the viscosity decreases (Fig. 2), which is caused by
oxidative degradation of CS. We did not observe
noticeable changes in the IR spectrum of the product
in comparison with the initial CS. It is likely that,
similarly to published data , treatment with hy-
drogen peroxide induces oxidative degradation with
the rupture of glycoside bonds in the CS molecule.
Fig. 1. Viscosity of CS solutions h as a function of shear
rate D. pH 4.5 and [CS] = 5.80 10