Russian Chemical Bulletin, International Edition, Vol. 57, No. 11, pp. 2332—2334, November, 2008
2332
Oxidation of valeraldehyde by chlorine dioxide
E. S. Ganieva, I. M. Ganiev, S. A. Grabovskiy, and N. N. Kabalnova
Institute of Organic Chemistry, Ufa Scientific Center of the Russian Academy of Sciences,
71 prosp. Oktyabrya, 450054 Ufa, Russian Federation.
Fax: +7 (347) 235 6066. Eꢀmail: oxboss@anrb.ru
The product of the reaction of valeraldehyde with chlorine dioxide was determined, and the
solvent effect on the reaction kinetics was studied. The major oxidation product is valeric acid.
The reaction rate is described by the secondꢀorder equation w = k[RCHO]•[ClO2]. The rate
constants were measured in the 297—328 K interval, and the activation parameters of the
reaction were determined.
Key words: oxidation, chlorine dioxide, valeraldehyde, rate constants, activation parameters.
with СH2N2. Benzene was used as a reference in the quantitative
determination of the products.
The oxidation of acetaldehyde and nꢀbutyraldehyde
by chlorine dioxide in an aqueous solution yields the corꢀ
responding carboxylic acids.1,2 Benzaldehyde dispersed in
water interacts with chlorine dioxide with explosion. At
the same time, it is reported that chlorine dioxide does
not react with hexanal and 2ꢀmethylbutanal.3
We identified the products and studied the kinetic
regularities of valeraldehyde oxidation by chlorine dioxide
in organic solvents.
Results and Discussion
The oxidation of valeraldehyde by chlorine dioxide
in the organic solvents listed above gives rise to valeric
acid with a high yield (>94%), and the complete converꢀ
sion of aldehyde is observed at the reactant mole ratio
ClO2/RCHO = 1.
Experimental
The curve change of the chlorine dioxide concenꢀ
tration as a function of time in excess aldehyde fits a
firstꢀorder equation with a correlation coefficient of
0.990—0.999. The kinetic curves of chlorine dioxide
consumption in the reaction with valeraldehyde in
1,4ꢀdioxane and their semilogarithmic transforms are
presented in Fig. 1. The apparent first order rate constants
Chlorine dioxide was obtained according to a known procedure.4
The solvents nꢀС7H16 (1), CCl4 (2), benzene (3), 1,4ꢀdioxane
(4), ethyl acetate (5), acetone (6), tertꢀbutanol (7), acetonitrile
(8), and ethanol (9) were purified by known procedures.5 The
kinetics of valeraldehyde oxidation by chlorine dioxide in various
solvents was studied on a Specord M40 spectrophotometer (Carl
Zeiss Jena) by a decrease in the absorbance at the absorption
maxima of ClO2 at 356, 359, 360, 354, 358, 361, 362, 363, and
360 nm in a medium of solvents 1—9 under the condition that
[ClO2]0 << [RCHO]0, where [ClO2]0 and [RCHO]0 are the
initial concentrations of chlorine dioxide and aldehyde. A
solution of valeraldehyde was placed in the working quartz cell,
and the reference cell was filled with a solvent. The temperature
of the cells was maintained at 24—55 °С in the spectrophotoꢀ
meter chamber. Then the necessary amount of a solution of
chlorine dioxide was added to the working cell, and the
change in the absorbance was monitored. The initial conꢀ
centrations of valeraldehyde and chlorine dioxide were varied
[ClO2]•104
/mol L–1
ln([ClO2]
3
2
t•10–3/s
/mol L–1
)
–7.0
9.6
8.4
7.2
6.0
4.8
3.6
–7.2
–7.4
–7.6
–7.8
–8.0
within (0.7—27.0)•10–2 mol L–1 and (0.5—1.2)•10–3 mol L–1
respectively.
,
The oxidation products were analyzed by the 1H and
13C NMR with a Bruker AMꢀ300 spectrometer at a frequency
of 300 MHz using CDCl3 as the solvent and SiMe4 as standard
and by GLC on a Chromꢀ5 instrument (column l = 3.5 m,
d = 3 mm, 5% SEꢀ30 on Chromatone) after sample treatment
1
2
3
t•10–3/s
Fig. 1. Kinetic curve of chlorine dioxide consumption in the
reaction of valeraldehyde in 1,4ꢀdioxane at 317 K ([RCHO]0 =
0.27 mol L–1).
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2287—2289, November, 2008.
1066ꢀ5285/08/5711ꢀ2332 © 2008 Springer Science+Business Media, Inc.