1070-4272/02/7508-1296 $27.00 C 2002 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 75, No. 8, 2002, pp. 1296!1303. Translated from Zhurnal Prikladnoi Khimii, Vol. 75, No. 8, 2002,
Original Russian Text Copyright + 2002 by Syroezhko, Proskuryakov, Begak.
AND INDUSTRIAL ORGANIC CHEMISTRY
Mechanism of Cyclohexane Ozonolysis
A. M. Syroezhko, V. A. Proskuryakov, and O. Yu. Begak
St. Petersburg State Technological Institute, St. Petersburg, Russia
Mendeleev Russian Research Institute of Metrology, State Unitary Enterprise, St. Petersburg, Russia
Received March 15, 2002
Abstract-A mathematical model of cyclohexane ozonolysis was developed. The reaction rate constants
were found experimentally or by fitting.
Experiments on reactions of ozone with saturated
hydrocarbons revealed a nonlinear dependence of the
rate constant on the hydrocarbon concentration .
At substrate concentrations less than 0.1 M, the reac-
tion was bimolecular.
These results were rationalized  by assuming
the formation of an intermediate complex RH...O
the same time, Korotkova  denies formation of
ozone3hydrocarbon complexes under these conditions.
Experiments on ozonolysis of cyclohexane and
methylcyclohexane show (Figs. 133) that, with in-
creasing substrate concentration, the apparent rate
For ozonolysis of cyclohexane under static condi-
tions, Galimova  found the following empirical
relationship between the rate constant and the ozone
and substrate concentrations:
= 3.2 0 10
/[RH] = k
` . (I)
According to , at oxygen content in the reac-
tion solution of 4.4 0 10
] = (4.336.0) 0 10
and [RH] = 9.25 M, k
= 9.5 0 10
In contrast to , it was shown in [4, 6, 7] that
the rate constant of hydrocarbon ozonolysis is an ap-
parent quantity taking into account the consumption
of ozone in nonchain and chain reactions:
]/dt = k
The experimental data (Fig. 2) show that the ex-
pression for the ozone consumption rate must in-
clude not only terms corresponding to nonchain and
chain reactions of ozone with the initial hydrocarbon,
but also those corresponding to further ozonolysis of
the reaction products such as cyclohexyl hydroperox-
ide, cyclohexanol, hydroxycyclohexyl peroxide, cy-
clohexanone, and e-caprolactone. The reactivities of
neat hydrocarbons, alcohols, and ketones toward
ozone are comparable (Table 1).
Fig. 1. Apparent rate constant k of hydrocarbon ozonolysis
at 22oC vs. reactant concentrations (measured spectropho-
tometrically): (1) cyclohexane and (2) methylcyclohexane.
[RH], M: (1) 1.339.25 and (2) 0.837.8.
Fig. 2. Kinetic curves of (1) ozone consumption, (2) ox-
ygen accumulation, and (3) variation of the concentration
of peroxide radicals RO
in the course of cyclohexane
ozonolysis. (t) Time; the same for Fig. 3.