Inorganic Chemistry
Article
′
′
k2,k−2
However, a notably higher average deviation found rather
supports the fact that the reaction is more likely to proceed via
the formation of OClOIO3.
−
ClO2 + IO − HoooooI ClO2 + IO 2−
(R2′)
(R3′)
4
4
′
k3
IO 2− + ClO2 + 2H+ → ClO2 + IO3− + H2O
−
4
AUTHOR INFORMATION
Corresponding Author
■
and the measured absorbance−time series were evaluated by
steps R1, R2′, and R3′ refining parameters k1, k2′, k−′ 2, and k3′.
We found a total correlation between k′−2 and k3′, meaning that
k1 = 26.9 0.2 M−2 s−1, k2′ = 36.9 0.1 M−2 s−1, and k3′/k−′ 2 =
Notes
The authors declare no competing financial interest.
0.74
0.02 can be determined from our data with an
acceptable average deviation of 0.0084 au. It is, however, ∼50%
higher than the best average deviation found by the proposed
model from which we concluded that, according to our data, it
is more likely that the reaction proceeds via the intermediate
OClOIO3. Because the proposed model contains the hydrolysis
of OClOIO3 and the reaction of this species with chlorite ion,
this behavior seems to be reminiscent of the case of Cl2O2 and
I2O2. It is generally well-known that subsequent reactions of
Cl2O2 and I2O2 are often subject to be affected by the
concentration of the buffer components as well. Performing
extra experiments when only the concentration of acetate was
changed between 0.038 and 0.265 mM and at pH = 3.55, we
found absolutely no effect of the concentration of buffer
components on the formation of chlorine dioxide, which is
quite different from the case of the reactions of Cl2O2 and I2O2.
In those systems, however, these species form in a rapid
preequilibrium established instantaneously but shifted far to the
left, meaning that kinetic features of the overall reaction should
also depend on the characteristics of their subsequent reactions.
In the present system, however, the rate-determining step is the
formation of OClOIO3; hence, the kinetic feature of their
subsequent reactions is not manifested in the overall kinetics.
Therefore, lack of buffer assistance in the present case can easily
be explained by the fact that the OClOIO3−chlorite direct
reaction takes place after the rate-limiting steps.
ACKNOWLEDGMENTS
■
Financial support of the Hungarian Research Fund OTKA
Grant No. K116591 is gratefully acknowledged. Financial
support for the “Environmental industry related innovative
trans- and interdisciplinary research team development in the
University of Pecs knowledge base” Project (SROP-4.2.2.D-15/
́
1/KONV-2015-0015) is gratefully acknowledged. The present
scientific contribution is dedicated to the 650th anniversary of
the foundation of University of Pec
́
s, Hungary.
REFERENCES
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Our present report may be treated as a comprehensive effort to
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