Russian Journal of Applied Chemistry, 2010, Vol. 83, No. 2, pp. 267−270.
Pleiades Publishing, Ltd., 2010.
Original Russian Text
A.G. Galstyan, S.G. Galstyan, N.F. Tyupalo, 2010, published in Zhurnal Prikladnoi Khimii, 2010, Vol. 83, No. 2, pp. 268−271.
AND INDUSTRIAL ORGANIC CHEMISTRY
Reaction of Toluene with Ozone in the Liquid Phase
A. G. Galstyan, S. G. Galstyan, and N. F. Tyupalo
Institute of Chemical Engineering, Dahl East-Ukrainian National University, Rubezhnoe, Lugansk oblast, Ukraine
Received April 22, 2009
Abstract—Reaction of toluene with ozone in acetic anhydride was studied. The dependence of the direction,
selectivity, and extent of oxidation on the reaction temperature, solvent nature, and catalyst composition was
Analysis of the reaction of methylbenzenes with
ozone in the liquid phase is highly practically important
for development of new low-temperature ecologically
safe methods for synthesis of oxygen-containing benzene
The present study is concerned with the liquid-phase
reaction of toluene with ozone. This object of study is due
to the comparative simplicity of the oxidizing system,
narrow spectrum of the expected reaction products, and
well-known methods of their identiﬁ cation .
The study demonstrated that toluene reacts with
ozone in acetic acid predominantly at the aromatic ring
to give ozonides. The oxidation selectivity at the methyl
group does not exceed 16%; the main products with
preserved aromatic structure are benzyl alcohol (BAlc),
benzaldehyde (BAld), and benzoic acid (BAc) (Fig. 1).
The oxidation selectivity at the methyl group increases
in the presence of cobalt(II) acetate, a typical catalyst for
oxidation of hydrocarbons in acetic acid ; the yield of
BAc at 95°C under the experimental conditions is as high
as 50%. In addition to BAc, BAlc and BAld were found
among aromatic reaction products in “trace amounts”
(Fig. 2). These substances cannot be obtained as main
reaction products under the conditions speciﬁ ed.
The composition of the reaction products changes in
the case of low-temperature oxidation in acetic anhydride
in the presence of manganese(II) acetate and sulfuric
acid. At a toluene conversion of 100%, the oxidation
selectivity at the methyl group at 5°C is as high as 90%.
Benzyl acetate (BAce) (42%), benzylidene diacetate
(BDAce)(18%), and BAld (30%) were found among the
reaction products; BAc accumulates upon exhaustive
oxidation of toluene (Fig. 3).
Under the conditions of catalysis by a stronger
manganese/bromide catalyst in the presence of a mineral
acid, oxidation terminates at the stage of BAld formation.
At a toluene conversion of 100%, the oxidation selectivity
at the methyl group is 90%. BDAce (71.2%), BAc (9.8%),
BAce (9%), molecular bromine, and trace amounts of
benzyl bromide were found among the reaction products;
benzoic acid appears in the ﬁ nal stage of oxidation
It is signiﬁ cant that cobalt(II) acetate loses its catalytic
activity in the presence of sulfuric acid: cobalt is in the
divalent state in the solution being oxidized, toluene is
almost not consumed at all under conditions of an intense
absorption of ozone.
The oxidation is hindered in the stage of formation of
the alcohol and aldehyde if cobalt(II) acetate is replaced
with a weaker catalyst, manganese(II) acetate (E
1.81 V, E
= 1.54 V), because hydroxy and
carbonyl groups are converted at the instant of their
formation to acetate and acylal groups, less stable against
the action of ozone (see table). The order in which
products of toluene oxidation are formed is shown in
the scheme (1).
The noncatalytic reaction of toluene with ozone at 5°C
is ﬁ rst-order with respect to the reactants. Presumably,
BAlc and BAld are formed at low temperatures by the
known scheme that does not include the reactions of