Kinetics and products of the reactions of ozone with toluene and its derivatives in acetic anhydride

Article abstract of DOI:10.1134/S0023158411040033

The reactions of ozone with toluene and its derivatives in acetic anhydride were studied. It was found that competing parallel reactions of ozone with the aromatic ring and substituents occurred in the ozone-arene-acetic anhydride system. The ratio between these reaction paths depended on the arene structure and reaction conditions. The selectivity of the oxidation of toluene and its derivatives at the methyl group varied from 0 to 40%. The fraction of aromatic products decreased as the number of methyl groups at the ring was increased. Tri- and tetramethylbenzenes were oxidized only at the aromatic ring. The stability of an aromatic system increased upon the introduction of electron-acceptor substituents into the benzene ring. Aminotoluenes and hydroxytoluenes were oxidized with ozone mainly at the NH₂ and HO groups; however, as in the case of toluene, the aromatic ring and methyl group became the main directions upon their acylation. The oxidation of the methyl group in acetic anhydride in the presence of sulfuric acid was finished at the step of the formation of the acylated derivatives of benzyl alcohols and benzaldehydes, which are resistant to the action of ozone.

Full text of DOI:10.1134/S0023158411040033

ISSN 0023ꢀ1584, Kinetics and Catalysis, 2011, Vol. 52, No. 4, pp. 493–498. © Pleiades Publishing, Ltd., 2011.
Original Russian Text © A.G. Galstyan, S.G. Galstyan, V.V. Lysak, 2011, published in Kinetika i Kataliz, 2011, Vol. 52, No. 4, pp. 504–509.
Kinetics and Products of the Reactions of Ozone with Toluene
and Its Derivatives in Acetic Anhydride
A. G. Galstyan, S. G. Galstyan, and V. V. Lysak
Institute of Chemical Technologies, EastꢀUkrainian National University, Rubezhnoe Branch,
Rubezhnoe, Lugansk oblast, Ukraine
eꢀmail: ozon@megabit.com.ua
Received December 14, 2009
Abstract—The reactions of ozone with toluene and its derivatives in acetic anhydride were studied. It was
found that competing parallel reactions of ozone with the aromatic ring and substituents occurred in the
ozone–arene–acetic anhydride system. The ratio between these reaction paths depended on the arene strucꢀ
ture and reaction conditions. The selectivity of the oxidation of toluene and its derivatives at the methyl group
varied from 0 to 40%. The fraction of aromatic products decreased as the number of methyl groups at the ring
was increased. Triꢀ and tetramethylbenzenes were oxidized only at the aromatic ring. The stability of an aroꢀ
matic system increased upon the introduction of electronꢀacceptor substituents into the benzene ring. Amiꢀ
notoluenes and hydroxytoluenes were oxidized with ozone mainly at the NH2 and HO groups; however, as in
the case of toluene, the aromatic ring and methyl group became the main directions upon their acylation. The
oxidation of the methyl group in acetic anhydride in the presence of sulfuric acid was finished at the step of
the formation of the acylated derivatives of benzyl alcohols and benzaldehydes, which are resistant to the
action of ozone.
DOI: 10.1134/S0023158411040033
INTRODUCTION
displacement along the horizontal axis. Acetic anhyꢀ
dride (chemically pure) was used as a solvent without
preliminary purification. Liquid methylbenzenes
(chemically pure) were purified on a column with aluꢀ
minum oxide. Solid methylbenzenes were recrystalꢀ
lized from appropriate solvents before use. Sulfuric
acid (chemically pure) was used as a mineral acid.
The ozone–air mixture with an ozone concentration
of 10–6–10–4 mol/l was obtained using a laboratory
ozone generator [4].
It is well known [1] that, in the ozone–methylbenꢀ
zene–acetic acid system, oxidation develops mainly at
the aromatic ring with the formation of ozonides. The
products of oxidation at the methyl group—benzoic
acids—are formed to a lesser extent (0–40%). Under
these conditions, the reaction of methyl group oxidaꢀ
tion cannot be stopped at the step of the formation of
aromatic alcohols because they are prone to further
oxidation [2]. However, previous studies [3] demonꢀ
strated the possibility of controlling the degrees of oxiꢀ
dation of toluene and its derivatives with ozone by
adding stop reagents to the system.
Acetic anhydride and sulfuric acid were loaded into
a thermostatically controlled reactor, and the resulting
mixture was saturated with ozone on shaking; thereafꢀ
ter, methylbenzene was introduced into the apparatus
(see Table 2 for concentration). The course of the
reaction was monitored based on changes in the conꢀ
centration of ozone in a gas phase and the analysis of
reaction products. Ozone concentrations in the gas
phase at the apparatus inlet and outlet were measured
automatically with the use of a spectrophotometric
technique in the absorption region of 254–290 nm. An
SFꢀ26 spectrophotometer equipped with a flow cell
7 cm in length coupled to an EPN potentiometer was
used for the measurements. The sensitivity to ozone
Here, we report the results of a study of the reacꢀ
tions of ozone with toluene and its derivatives in acetic
anhydride, which is a strong acylating agent. From sciꢀ
entific and practical points of view, this study is imporꢀ
tant for the development of promising methods for
controlling the selectivity and degree of oxidation of
alkylbenzenes with ozone in a liquid phase.
EXPERIMENTAL
The oxidation of toluene and its derivatives was was 1.8
performed in a thermostatically controlled catalytic calculated using a calibration curve constructed with
reactor as a longꢀnecked flask 0.1 l in volume under the use of the equation [O3]g = , where [O3]g is the
conditions of the kinetic regime of oxidation, which ozone concentration in a gas phase, mol/l; is the
was observed at a reactor shaking frequency higher absorbance of ozoneꢀcontaining gas; is the molar
than 7–9 s–1 (depending on the nature of the arene absorption coefficient (
= 3025 at = 254 nm [5]);
is the optical path length of the cell (2–7 cm).
×
10–7 mol/l. The concentration of ozone was
A/ l
ε
A
ε
ε
λ
and reaction conditions) and a 0.04ꢀm amplitude of its and
493
l

494
GALSTYAN et al.
Table 1. Selectivity for the oxidation of toluene and its derivatives in acetic anhydride; [H2SO4]0 = 0.08–1.2 mol/l
Compound
Toluene
t
, °C
β
, %
S
, %
S , %
2
1
5
5
70.0
82.0
80.0
6.0
5.0
4.8
0.0
0.0
0.0
0.0
91.3
93.1
93.2
98.3
98.7
98.5
98.1
62.4
61.0
56.1
58.4
89.6
94.6
95.1
96.2
88.2
79.7
78.0
–
1,4ꢀDimethylbenzene
1,3ꢀDimethylbenzene
1,2ꢀDimethylbenzene
1,3,5ꢀTrimethylbenzene
1,3,4ꢀTrimethylbenzene
2,3,5,6ꢀTetramethylbenzene
4ꢀNitrotoluene
5
5
100.0
100.0
100.0
100.0
28.4
5
5
5
20
20
30
30
30
5
32.5
34.1
42.2
39.8
8.2
4ꢀToluenesulfonyl chloride
3,4ꢀDinitrotoluene
2,4ꢀDinitrotoluene
2,6ꢀDinitrotoluene
2ꢀHydroxytoluene
3ꢀHydroxytoluene
4ꢀHydroxytoluene
2ꢀAcetoxytoluene
32.0
92.2
92.0
91.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
0.0
5
0.0
5
0.0
5
10.9
19.9
20.5
0.0
3ꢀAcetoxytoluene
5
4ꢀAcetoxytoluene
5
2ꢀAminotoluene
5
3ꢀAminotoluene
5
0.0
–
4ꢀAminotoluene
5
0.0
–
2ꢀAcetaminotoluene
3ꢀAcetaminotoluene
4ꢀAcetaminotoluene
5
5.6
92.0
83.2
81.6
5
13.2
15.6
5
Note: β is the conversion; S is selectivity for oxidation at the methyl group; S is the concentration of peroxides—benzene ring oxidation
1
2
products; hydroxyꢀ and aminotoluenes were oxidized in acetic acid.
The oxidation products of toluene and its derivaꢀ concentration in the gas phase at the reactor outlet in
time, and the equation
tives were identified and their concentrations in soluꢀ
tion were determined by gas–liquid chromatography
on a chromatograph with a flameꢀionization detector
(3ꢀm column 4 mm in diameter; solid support, Inerꢀ
ton AWꢀDMCS; stationary phase, SEꢀ30 (5%)). The
n
m
keff = ω O − O
α O
ArH ,
[
(
]
[
]
[
3]f [
]
)
3
f
3
i
0
where
ω
is the gas flow rate, 1/s;
α
is the Henry coefꢀ
ficient; [ArH]0 is the initial substrate concentration,
mol/l; [O3]i and [O3]f are the concentrations of ozone
injector temperature was 250
°
С
, and the oven temperꢀ
in the gas phase before and after the reactor, mol/l;
and are reaction orders with respect to reactants.
n
ature was programmed over a range of 100–200
°С
for
m
a specified time. The carrierꢀgas (nitrogen), hydrogen,
and air flow rates were 1.8, 1.8, and 18 l/h, respecꢀ
tively. 4ꢀNitrochlorobenzene was used as an internal
standard.
The concentration of peroxides was determined by
iodometric titration.
RESULTS AND DISCUSSION
The effective rate constants of the reactions of
ozone with methylbenzenes and their oxidation prodꢀ
ucts were determined with the use of ozone diagrams,
Toluene in an acetic anhydride solution was oxiꢀ
dized with an ozone–air mixture at
5°С mainly at the
benzene ring with the formation of peroxides (91.3%),
kinetic curves, which characterize changes in ozone which are resistant to the action of ozone, and benzoic
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KINETICS AND PRODUCTS OF THE REACTIONS OF OZONE
495
Table 2. Rate constants of the reactions of ozone with toluene and its derivatives in acetic anhydride at 5°C; [H2SO4]0 =
0.08–1.2 mol/l
Concentration, mol/l
Compound
k
eff, l mol–1 s–1
n
* =
Δ
[O ]/
Δ
[ArH]
3
2
4
[ArH]
×
10
[O ] × 10
3 0
0
Toluene
1.0–10.20
0.20–1.40
0.20–1.26
0.04–0.28
0.05–0.40
0.02–0.23
2.1–20.82
9.11–22.6
9.11–22.6
9.11–22.6
9.7–38.3
0.1–1.20
0.2–1.20
0.56 0.05
3.02 0.28
2.81 0.26
32.00 2.95
17.83 1.62
56.84 1.21
0.04 0.003
0.01 0.001
0.01 0.001
0.008 0.001
(0.96 0.08)
(2.26 0.20)
0.47 0.04
0.56 0.05
0.59 0.05
(2.46 0.20)
(2.15 0.20)
(2.66 0.20)
1.45 0.19
0.56 0.04
1.53 0.12
3.17
2.81
–
1,4ꢀDimethylbenzene
1,3ꢀDimethylbenzene
1,3,5ꢀTrimethylbenzene
1,3,4ꢀTrimethylbenzene
1,3,5,6ꢀTetramethylbenzene
4ꢀNitrotoluene
0.21–1.15
0.31–2.00
0.32–2.10
0.20–1.31
0.11–2.56
0.18–3.38
0.18–3.30
0.18–3.32
0.35–0.90
0.35–0.90
0.29–0.57
0.28–0.57
0.28–0.57
0.45–0.80
0.45–0.89
0.45–0.80
0.28–0.57
0.28–0.57
0.28–0.57
3.06
–
–
2.10
1.02
1.09
1.11
–
3,4ꢀDinitrotoluene
2,4ꢀDinitrotoluene
2,6ꢀDinitrotoluene
2ꢀHydroxytoluene
4ꢀHydroxytoluene
2ꢀAcetoxytoluene
3
3
×
×
10
10
9.9–31.9
–
20.1–38.9
15.1–35.9
15.1–35.9
2.7–18.3
1.12
1.09
1.07
–
3ꢀAcetoxytoluene
4ꢀAcetoxytoluene
3
3
3
2ꢀAminotoluene
×
×
×
10
10
10
3ꢀAminotoluene
2.7–18.3
–
4ꢀAminotoluene
2.7–18.3
–
2ꢀAcetaminotoluene
3ꢀAcetaminotoluene
4ꢀAcetaminotoluene
10.1–29.7
15.1–29.7
10.1–29.7
1.25
1.30
1.35
Note: k was calculated on condition that the reaction of ozone with methylbenzenes is of first order with respect to reactants (as determined
eff
experimentally); * stoichiometric coefficient for ozone.
acid (the product of oxidation at the methyl group) in acetate (7.9%), 4ꢀnitrobenzylidene diacetate (24.6%),
considerably smaller amounts (5.8%). Benzyl alcohol, and trace amounts of 4ꢀnitrobenzaldehyde were
benzaldehyde, and their acylated derivatives (benzyl
acetate and benzylidene diacetate, the total amount of
which was no higher than 10–4 mol/l) appeared at the
early stages.
detected among the oxidation products. The introducꢀ
tion of the second nitro group into the benzene ring
led to a further increase in the fraction of selective oxiꢀ
dation: 3,4ꢀdinitrotoluene was oxidized with the formaꢀ
tion of 3,4ꢀdinitrobenzyl acetate (10.2%), 3,4ꢀdinitrobenꢀ
zylidene diacetate (32.0%), and trace amounts of 3,4ꢀ
dinitrobenzyl alcohol and 3,4ꢀdinitrobenzaldehyde.
Analogous results were obtained upon the oxidation of
4ꢀtoluenesulfonyl chloride and 2,4ꢀdinitrotoluene.
The selectivity of the oxidation of ortho isomers was
lower because of steric hindrances.
In the presence of the catalytic additives of sulfuric
acid (0.8 mol/l), benzyl acetate (3.8%), benzylidene
diacetate (2.2%), and benzaldehyde, whose concenꢀ
tration in solution was no higher than
4
10–4 mol/l,
×
were detected among the products of oxidation at the
methyl group. Benzoic acid was not detected under
these conditions (Table 1).
The introduction of the second, third, and fourth
methyl groups into the aromatic ring of toluene led to
a decrease in the selectivity of oxidation (Table 1).
Upon the oxidation of 1,4ꢀdimethylbenzene, 4ꢀmethꢀ
ylbenzylidene diacetate (4.6%) and 4ꢀmethylbenzyl
The stability of an aromatic system in the reaction
with ozone increased upon the introduction of elecꢀ
tronꢀacceptor substituents into the aromatic ring
(Table 1). Upon the oxidation of 4ꢀnitrotoluene in an
acetic anhydride solution in the presence of sulfuric
acid at a temperature of 20
°С, the selectivity of the process acetate (0.4%) were identified among the oxidation
for the methyl group increased to 32.5%: 4ꢀnitrobenzyl products of the methyl group. 1,2ꢀDimethylbenzene
KINETICS AND CATALYSIS Vol. 52
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GALSTYAN et al.
Table 3. Oxidation of acetoxyꢀ and acetaminotoluenes with ozone in acetic anhydride at 5°C. [ArCH ] = 0.4;
3 0
–4
[O ] = 4
×
10 mol/l
3 0
Yield of oxidation products, %
Compound
[H SO ] , mol/l
2 4 0
benzylidene
benzyl acetates
peroxides
benzoic acids
diacetates
–
87.7
88.2
4.3
7.4
1.9
3.5
4.6
–
2ꢀAcetoxytoluene
3ꢀAcetoxytoluene
4ꢀAcetoxytoluene
2ꢀAcetaminotoluene
3ꢀAcetaminotoluene
4ꢀAcetaminotoluene
1.2
–
79.7
79.1
7.5
3.2
7.3
8.6
–
1.2
12.6
–
78.6
78.0
7.8
3.4
7.5
9.2
–
1.2
13.0
–
92.4
92.0
2.0
3.2
1.2
2.4
2.3
–
1.1
–
83.9
83.2
4.1
8.0
3.1
5.2
5.8
–
1.1
–
82.1
81.6
5.2
9.3
4.1
6.5
6.3
–
1.1
was almost completely converted into benzene ring of oxidation at the methyl group—acetoxybenzyl aceꢀ
oxidation products. Triꢀ and tetramethylbenzenes also tates (4.3–7.8%), acetoxybenzylidene diacetates
reacted with ozone only at the aromatic ring (Table 1). (1.9–3.4%), and acetoxybenzoic acids (4.6–9.2%).
In the presence of acid acylation catalysts, for
The reaction of ozone with toluene derivatives havꢀ
example, sulfuric acid, the total selectivity of oxidaꢀ
tion remains almost unchanged, but the oxidation of
methyl group completes at the stage of formation of
acetoxybenzyl acetates and acetoxybenzylidene diaceꢀ
tates (Table 3).
We found experimentally that at least the following
two conditions should be fulfilled for the accumulaꢀ
tion of benzyl acetates and benzylidene diacetates in
the system:
ing HO– and NН2– groups at the benzene ring occurs
in a different way. At the initial moment of time,
hydroxytoluenes in a tetrachloromethane solution
react with ozone at the H–O bond of the hydroxyl
group with the formation of phenoxyl radical with the
subsequent addition of a hydroxyl radical, benzene
ring opening, and formation of ozonides—the prodꢀ
ucts of the addition of ozone molecules at double
bonds [1]. The rate of a primary attack by ozone is so
high (Table 2) that the reactions of ozone at the double
bonds of an aromatic ring and the methyl group can be
ignored (Table 1).
(1) The rate of acylation of alcohols and aldehydes
formed upon oxidation should be considerably higher
than the rate of their ozonation.
(2) The rate of ozonation of the resulting benzyl
acetates and benzylidene diacetates should be no
higher than the rate of ozonation of the corresponding
toluenes.
In an acetic anhydride solution, the reaction
mechanism changes because hydroxytoluenes are rapꢀ
idly acylated under the experimental conditions (the
acylation it complete at the stage of reagent preparaꢀ
tion). In this case, the O–C bond, which is stronger
than H–O, is formed [6] and the direction of reaction
changes and becomes typical of ozone reactions with
alkylbenzenes—at the double bonds of an aromatic
ring and at the methyl group [1]. The found reactivity
of hydroxytoluenes and acetoxytoluenes confirms this
conclusion: after the acylation of hydroxytoluenes, it
decreases by three orders of magnitude and approaches
the reactivity of methylbenzenes (Table 2). In this case,
oxidation is mainly developed at the benzene ring and
the methyl group (Table 3). In the absence of a mineral
For the quantitative assessment of the first condiꢀ
tion, the rates of ozonation and acylation of benzyl
alcohol were determined. The rate of acylation of benꢀ
zyl alcohol was found considerably higher than the rate of
its ozonation (3.3
×
10–2 and 2.3
×
10–4 mol l–1 s–1,
respectively;
satisfied.
T = 20°С); that is, the first condition is
The second condition is also satisfied: the effective
reaction rate constant of ozone with benzyl acetate
does not exceed the rate constant of ozonation of tolꢀ
uene (
Thus, the formation of the products of the partial
k
eff = 0.56 and 0.87 l mol–1 s–1, respectively).
acid at a temperature of 5°С, the main reaction prodꢀ
ucts are peroxides—benzene ring oxidation products oxidation of toluene and its derivatives at the methyl
(78.6–87.7%)—and, to a lesser degree, the products group in an acetic anhydride solution is caused by the
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KINETICS AND PRODUCTS OF THE REACTIONS OF OZONE
497
fast acylation reactions of benzyl alcohols and benzalꢀ tem with the formation of corresponding benzyl aceꢀ
dehydes at the moment of their appearance in the sysꢀ tates and benzylidene diacetates:
R
R
R
R
HOH C
AcOH C
2
2
+
O
A
c O, H
2
3
R
H C
3
(AcO)2HC
OHC
where R = –H, –CH3, –NO2, –SO2Cl, –OAc, or
After acylation, the effective rate constant of ozone
interaction with aminotoluenes ( eff) decreases by
three orders of magnitude and approaches the values
of eff characteristic of methylbenzenes (Table 2). Aceꢀ
taminobenzyl acetates (2.0–5.2%), acetaminobenꢀ
zylidene diacetates (1.2–4.1%), acetaminobenzoic
acids (2.3–6.3%), and trace acetaminobenzaldehyde
were detected among the products of oxidation at the
methyl group in the absence of a catalyst for acylation
⎯
NHAc.
k
Aminotoluenes react with ozone more rapidly than
k
hydroxytoluenes (Table 2). The reaction mainly
occurs at the lone electron pair of the nitrogen atom
with the predominant formation of tar products (it is
assumed that these are polymeric azo compounds [7]),
nitrotoluenes (to 14%), and trace toluquinones. The
products of oxidation at the methyl group are not
reaction (sulfuric acid) at 5ºС (Table 3). Under the
formed at 5–15°С under conditions of the experiꢀ
conditions of sulfuric acid catalysis at the same selecꢀ
tivity of oxidation, the main reaction products are acyꢀ
lated alcohols and aldehydes (Table 3).
ments. After the acylation of the amino group, as in
the case the ozonation of hydroxytoluenes, oxidation
at the aromatic ring (81.6–92.0%) and the methyl
group (5.6–15.6%) become the main reaction paths
(Table 1). In this case, the amino group is deactivated
to a considerable degree as a result of the formation of the
–N–C bond, which is stronger than N–H, and the parꢀ
Based on published data [4] and the experimental
results, we can make the following conclusions:
(1) The general reaction scheme of the oxidation of
ticipation of the lone electron pair of the nitrogen atom in toluene and its derivatives in acetic anhydride in the
conjugation with the carbonyl group of acetyl [6].
presence of sulfuric acid has the form
•
•
(I)
+ O2 + HO
CH2
R
+
k
Ac O, H
2
eff
+ O3
CH3
(II)
(III)
– O2
CH2OAc
CH2OH
R
R
R
R
2O
3
rapidly
oz
CH3
O3
where R = –H, –CH3, –NO2, –SO2Cl, –OAc, or paths (I)–(III) become possible after the preliminary
⎯
NHAc; oz refers to ozonides.
In this case, reaction path (3) is predominant.
(2) The amount of aromatic products decreases
acylation of the hydroxy and amino groups.
Benzyl radicals formed in reaction (I) are oxidized
in accordance with the following reaction scheme of
chain oxidation [8]:
with the number of methyl groups at the benzene ring.
i
i
R–
+ O2
R–
(IV)
ArCH2
ArCH2O2
(3) The stability of the benzene ring in the reaction
with ozone increases upon the introduction of elecꢀ
tronꢀacceptor substituents into the ring.
(4) Hydroxyꢀ and aminotoluenes react with ozone
mainly at the hydroxy and amino groups; reaction
R−ArCH2Oi2 + ArCH3
(V)
→ R−ArCH2O2H +ArCHi2,
R–ArCH2O2H
R–ArCH2O• + HO•
(VI)
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498
GALSTYAN et al.
2R−ArCH2Oi2
R−ArCH2OH + AC2O
(VIII)
(IX)
(VII)
→ R−ArCH2OAc + AcOH,
→ R−ArCH2OH + ArCHO.
R–ArCHO + Ac2O
R–ArCH(OAc)2.
Rough estimates show that the chain length for tolꢀ
uene is ωV ωI ≈ 27 (ωI eff[O3]0[ArH]0 ' = 0.87
0.1 0.06 = 4.0
10–7 mol l–1 s–1,
The properties of the resulting peroxides are almost
the same as the properties of peroxides obtained upon
the oxidation of methylbenzenes in an acetic acid
solution [4]: they are resistant to the action of ozone;
they are accumulated upon oxidation at a high rate in
a high yield (Table 1); they are light yellow viscous liqꢀ
uid readily soluble in acetic acid and acetic anhydride.
The stoichiometric coefficient of the reaction
=
/
=
k
·
S
×
v
1.2
×
10–4
×
×
×
ωV
=
k
V[ArCH2O•2][ArH]0 = 1.0
10–4
0.1= 1.1
×
1.1
×
×
×
10–5 mol l–1 s–1, where
S' is the selectivity of oxidation
i
⎡
⎣
⎤
≈
⎦
at the methyl group (Table 1, 6.0%);
ArCH2O2
1.1
tration conditions at
[11];
eff = 0.56 l mol–1 s–1 (Table 2)).
×
10–4 mol/l was found from steadyꢀstate concenꢀ
kV = 1.0 [11];
VII = 108 l mol–1 s–1
Δ
[O3]0/ [ArCH3]0 found some toluene derivatives is
1–3 (Table 2). According to published data [4, 7], the
above facts suggest that peroxides are monomers, triꢀ
Δ
k
k
The alcohols and aldehydes formed in the system mers, or their mixtures with a linear structure dependꢀ
are converted into acetates and acetals, which are ing on the structure of the arene; the preparation of
resistant to the action of ozone, in an acetic anhydride them can be described in accordance with the Kriege
solution [9, 10]:
mechanism:
O
C
H
AcOH
O
H
H
C
OOH
O
O
C
C
H
H
O
3
R
OAc
O
H
O+
3R
C
C
H
R
R
R
2O
O−
(X)
3
O
O+ O−
R
H
R
R
C
R
C
R
C
AcOH
3R
C
O
C
OOH
R
C
C
OO
OO
C
OOH
OAc
O
OAc
HO OAc
HO OAc
3. Galstyan, G.A., Matsegora, L.A., and Rister, O.I., Zh.
Prikl. Khim., 1982, vol. 55, p. 2547.
4. Razumovskii, S.D. and Zaikov, G.E., Ozon i ego reaktsii
s organicheskimi soedineniyami (Ozone and Its Reactions
with Organic Compounds), Moscow: Nauka, 1974.
Thus, we found that ozone reacts with toluene and
its derivatives in acetic anhydride predominantly at the
benzene ring. The amount of the products of oxidation
at the methyl group decreases with the number of
methyl groups at the benzene ring, whereas it increases
in the presence of electronꢀacceptor substituents.
Aminoꢀ and hydroxytoluenes in acetic acid react with
ozone mainly at the amino and hydroxy groups, but
the benzene ring and the methyl group become the
main directions of reaction after their acylation. The
oxidation of the methyl group in acetic anhydride and
in the presence of sulfuric acid becomes complete at
the stage of the formation of acylated benzyl alcohol
and benzaldehyde derivatives, which are resistant to
the action of ozone.
5. Calvert, J.G. and Pitts, J.N., Photochemistry, New
York: Wiley, 1965.
6. Gurvich, L.V., Karachintsev, G.B., and Kondrat’ev, V.N.,
Energii razryva khimicheskikh svyazei. Potentsialy ionꢀ
izatsii i srodstvo k elektronu (Bond Dissociation Enerꢀ
gies, Ionization Potentials, and Electron Affinity),
Moscow: Nauka, 1974.
7. Bailey, P.S., Ozonation in Organic Chemistry: Nonꢀ
olefinic Compaunds, New York: Academic, 1982, vol. 2.
8. Emanuel’, N.M., Denisov, E.T., and Maizus, Z.K.,
Tsepnye reaktsii okisleniya uglevodorodov v zhidkoi faze
(Chain Oxidation Reactions of Hydrocarbons in the
Liquid Phase), Moscow: Nauka, 1965.
REFERENCES
9. Traffers, H.P. and Hammett, L.P., J. Am. Chem. Soc.
1937, vol. 59, p. 1708.
,
1. Galstyan, G.A., Tyupalo, N.F., and Razumovskii, S.D.,
Ozon i ego reaktsii s aromaticheskimi soedineniyami v 10. Gillespie, R.J., J. Am. Chem. Soc., 1950, vol. 39,
zhidkoi faze (Ozone and Its LiquidꢀPhase Reactions
with Aromatic Compounds), Lugansk: VUNU, 2004.
2. Galstyan, G.A. and Galstyan, T.M., Neftekhimiya
1994, vol. 30, p. 829.
p. 2997.
11. Denisov, E.T., Konstanty skorosti gomoliticheskikh zhidꢀ
kofaznykh reaktsii (Rate Constants of Homolytic Liqꢀ
uidꢀPhase Reactions), Moscow: Nauka, 1971.
,
KINETICS AND CATALYSIS Vol. 52
No. 4
2011