Reactions of benzo and dibenzo derivatives of five-membered aromatic heterocycles with ozone in the liquid phase

Article abstract of DOI:10.1134/S0965544115020036

The ozonation reactions of benzo and dibenzo derivatives of pyrrole, furan, and thiophene in acetic acid solution have been studied. Peroxide compounds have been detected as the products. The mechanism of ozone interaction with these hetarenes has been proposed. The kinetics of ozonolytic reactions of benzologues of five-membered aromatic heterocycles (hetarenes) have been investigated. The reaction of ozone with the hetarenes obeys the bimolecular rate law and has the first order in each reactant. The effective rate constants and experimental stoichiometric coefficients for ozone have been found.

Full text of DOI:10.1134/S0965544115020036

ISSN 0965ꢀ5441, Petroleum Chemistry, 2015, Vol. 55, No. 6, pp. 497–502. © Pleiades Publishing, Ltd., 2015.
Original Russian Text © P.Yu. Andreev, 2015, published in Neftekhimiya, 2015, Vol. 55, No. 4, pp. 347–352.
Reactions of Benzo and Dibenzo Derivatives of FiveꢀMembered
Aromatic Heterocycles with Ozone in the Liquid Phase
P. Yu. Andreev
Institute of Chemical Technologies, Dahl East Ukrainian National University, Rubezhnoe, Ukraine
eꢀmail: panyaa@rambler.ru
Received July 8, 2014
Abstract—The ozonation reactions of benzo and dibenzo derivatives of pyrrole, furan, and thiophene in aceꢀ
tic acid solution have been studied. Peroxide compounds have been detected as the products. The mechanism
of ozone interaction with these hetarenes has been proposed. The kinetics of ozonolytic reactions of benzoꢀ
logues of fiveꢀmembered aromatic heterocycles (hetarenes) have been investigated. The reaction of ozone
with the hetarenes obeys the bimolecular rate law and has the first order in each reactant. The effective rate
constants and experimental stoichiometric coefficients for ozone have been found.
Keywords: peroxide oxidation, fiveꢀmembered nitrogen heterocycles, liquidꢀphase reactions
DOI: 10.1134/S0965544115020036
Benzo and dibenzo derivatives of fiveꢀmembered determined by GLC using an LKhMꢀ80 chromatoꢀ
hetarenes are characterized by usual electrophilic subꢀ graph with FID on a 2ꢀm column packed with polymꢀ
stitution reactions typical of aromatic compounds [1]. ethylphenylsiloxane (PMPSꢀ6)ꢀcoated Chromaton
The electrophilic substitution reactions of these NꢀAW. Peroxides were determined by iodometry after
hetarenes proceed in the same way as for pyrrole, the reactor with air to remove ozone residue according
furan, and thiophene, but some peculiarities due to the to the published procedure [6]. The concentration of
stabilizing effect of the benzene ring caused by the carboxylic acids was determined by alkalimetric titraꢀ
electronꢀwithdrawing action on the fiveꢀmembered tion with a 0.05 N sodium hydroxide solution after solꢀ
heterocycle should be noted.
vent evaporation. The IR spectra were recorded on a
URꢀ20 spectrophotometer in KBr disks.
Electrophilic substitution occurs exclusively in the
The ozone concentration in the gas phase was
determined using the spectrophotometric method
based on measuring the UV absorbance of gas flow in
the range of 254–290 nm. The ozone uptake was
determined as the difference of its concentrations at
the reactor inlet and outlet, taking into account the
air–ozone mixture feed rate. The kinetics of ozone
consumption was studied using a Spektromomꢀ202
spectrophotometer with a quartzꢀwindowed flow cell
placed in its measurement compartment. The cell
material was Teflon. The ozone detection limit of the
instrument was 10–7 mol/dm3.
3ꢀposition of the heterocycle in the indole molecule (I),
predominantly in the 2ꢀposition in benzofuran (II),
and in the 3ꢀposition with a considerable impurity of
the 2ꢀisomer in thionaphthene (III) [1–3]. The elecꢀ
trophilic substitution and oxidation reactions of comꢀ
pounds I–III, as well as those of carbazole (IV),
dibenzofuran (V), and dibenzothiophene (VI), have
been reported [1–4], but there is a lack of data on the
reaction of these compounds with ozone as an electroꢀ
philic oxidant. In this study, we examined the reaction
of hetarenes I–VI with ozone in a solution of glacial
acetic acid.
RESULTS AND DISCUSSION
EXPERIMENTAL
The oxidation of compounds I–III with ozone was
considered in [7–9]. It was shown that during the ozoꢀ
nation of benzo derivatives I–III in chloroform, the
C–C heterocycle bond is cleaved and 1–1.8 mol of
ozone per mole of hetarene is absorbed. The reactions
of ozone with dibenzo derivatives IV–VI were not
reported.
The oxidation of hetarenes I–VI was carried out in
a temperatureꢀcontrolled reactor made as a glass colꢀ
umn of a 0.1 dm3 volume equipped with a finely
porous separating wall for dispersing an ozone–air
mixture and a reflux condenser. The reactor was
charged with 0.05 dm3 of glacial acetic acid and a calꢀ
culated amount of hetarene; then, the ozone–air mixꢀ
ture was supplied at a rate of 3.3
×
10–3 dm3/s. The
Earlier, in the investigation of the reaction of fiveꢀ
amount of the reactant hetarenes in solution was membered hetarenes [10] and their methyl derivatives
497

498
ANDREEV
Stoichiometric characteristics of interaction of ozone with pyrrole, furan, thiophene, and their benzo I–III and dibenzo
IV–VI derivatives in glacial acetic acid at 290 K. [ArH]0 = 1.0
10–2; [O3]0 = 4.0 10–5 mol/dm3
×
×
Concentration of peroxides, mol/dm3 102
×
mol O3
ꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀ
mol ArH
Hetarene
nexp
,
k
eff, dm3/(mol s)
in 1 h
in 24 h
Pyrrole
1.95
1.91
1.74
3.84
3.73
3.62
5.61
5.63
5.64
1.15
1.03
0.95
0.92
0.92
0.88
1.95
1.92
1.94
1.91
1.88
1.64
1.95
1.85
1.80
1.82
1.78
1.79
1.8
1.2
×
×
105
103
Furan
Thiophene
34.8
(
(
(
(
(
(
I
)
2.0
2.1
×
×
103
102
II
III
IV
)
)
8.5
)
76.0
0.9
V
)
VI
)
0.26
[11] with ozone in acetic acid, we detected linear bond to attack the bond with the lowest localization
hydroperoxyperoxides as the primary products. The energy of the aromatic system.
experimentally found stoichiometric coefficient for
ozone, exp, was 1.95–1.74 mol per mole of heteroarꢀ
omatic substrate. The effective rate constant of ozoꢀ
nolysis of pyrrole, furan, and thiophene, eff, varies
within 1.8
105–34.8 L/(mol s) depending on the
Proceeding from the foregoing, it may be assumed
that the interaction of ozone with compounds I–III
can be described as given in Scheme 1 according to
which the reaction follows the classical mechanism
n
k
×
including the step of formation of the
followed by the primary attack of ozone at the carbon
atom predominantly in the ꢀposition for hetarene or
III and in the ꢀposition for II, giving rise to ꢀcomꢀ
π
ꢀcomplex (VII)
nature of the heteroatom (table) [10].
β
I
On the basis of the experimental results and pubꢀ
lished data [7–9], the mechanism of ozone interaction
with benzo derivatives I–III in acetic acid solution at
290 K was proposed, according to which the first step
is the fast electrophilic attack of ozone across the douꢀ
ble bond of heterocycle with absorption of 1 mol of O3
per mole of substrate and formation of ozonides,
which are subsequently transformed via the degradaꢀ
α
σ
plex (VIII) converting into ozonides (IX). The latter,
depending on the structure of the reactant benzo
derivative, are transformed by the ring opening of hetꢀ
erocycle into 2ꢀaminobenzaldehyde (
hyde (XI), or thiosalicylaldehyde (XII).
Resulting benzaldehydes X–XII, in turn, are interꢀ
ꢀelecꢀ
X), salicylaldeꢀ
tion of the heterocycle according to Scheme 1. In mediate compounds; after ozone attack at the
π
reactions with I–III, ozone acts as a typical electroꢀ tron system of the aromatic ring, they are transformed
phile and reacts by the (2–3) double bond of the hetꢀ into peroxide compounds. About 3 mol of O3 per mole
erocycle to give the products of decomposition of the of substrate is additionally absorbed to give triozonide
aromatic system according to published data [7, 8] followed by the degradation of the aromatic cycle and
that showed ozone as a specific reagent for double the formation of peroxide compounds.
O
O
O3
+ O3
+
–O
O
X
X
)
X
(I
)–(III
)
(
VII
(
VIII)
O
CHO
XH
peroxide
compounds
3O3 +
O
X
(X
)–(XII
)
(IX)
Scheme 1.
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REACTIONS OF BENZO AND DIBENZO DERIVATIVES
499
%
80
60
40
20
42
38
34
30
26
22
18
14
10
6
2
×
100 cm–1
Fig. 1. IR absorption spectrum of 2,2'ꢀdicarboxydiphenylsulfide (XIII) obtained through oxidation of thionaphthene (III) and
dibenzothiophene (VI) with ozone in acetic acid at 290 K.
The peroxide compounds studied after completion also moderately weak absorption bands at 2560 cm–1
of ozonation react with potassium iodide in two steps:
molecular iodine is released in the amount equivalent
to one final hydroperoxide group during the first, rapid
step (duration 1 h) and the equivalent of another two
groups is released during the second, slow (24 h) step
due to sulfide group S–S vibrations and bands at
3020 cm–1 due to C–H vibrations in the aromatic ring.
Overall experimental stoichiometric coefficient
nexp found of ozone decreases in the order I > II > III
(table). According to published data [10], hydroperoxꢀ from 3.84 to 3.56 mol per mole of hetarene (table).
ide groups readily react with KI; whereas the peroxide
groups of dialkylperoxides, are more difficult to
reduce.
The reduced consumption of ozone for oxidation of
III is associated with the fact that thiosalicylaldehyde
XII can partially add 2, rather than 3 mol of O3
involved in the oxidative condensation and formation
In the case of oxidation of thionaphthene III, 2,2'ꢀ
dicarboxydisulfide (XIII) was detected as the final
product; its yield 26.7% of the oxidation products.
of 2,2'ꢀdicarboxydiphenylsulfide XIII
.
During the ozonation of dibenzo derivatives IV–VI
in a solution of acetic acid at 290 K, the first step is the
electrophilic attack of ozone across the double bonds
of one of the carbocycles with the absorption of 2 mol
of O3 per mole of the substrate and the formation of
diozonide (XIV), which subsequently transforms via
two routes according to Scheme 2.
COOH HOOC
S
S
(XXIIIIII)
By the first route according to Scheme 2, diozonide
XIV adds another 2 mol of O3 and transforms into tetꢀ
raozonide (XV), which degrade to give peroxide comꢀ
pounds (their structures has not been studied in this
work). The ozonation products, depending on the
nature of the initial dibenzo derivative, were found to
contain about 15–20% pyrroltetracarboxylic (XVI),
furantetracarboxylic (XVII), and thiophenetetracarꢀ
boxylic (XVIII) acids, which can be produced through
Thiosalicylaldehyde
(
XII
)
supposedly adds
approximately 2 mol of O3, and oxidative condensaꢀ
tion yielding XIII occurs. The feasibility of this conꢀ
densation has been demonstrated in [13].
To confirm the structure, the IR spectra of comꢀ
pound XIII were recorded. The resulting IR spectra
depicted in Fig. 1 show absorption bands at 740 cm–1
due to C–S stretching vibrations, 1470 and 1590 cm–1
due to the benzene ring C–C vibrations, and 1720 cm–
1
due to C=O carboxylic group vibrations. There are the degradation of ozonide IX
.
PETROLEUM CHEMISTRY Vol. 55
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500
ANDREEV
O
O
O
O
+ 2O3
X
X
O
O
(
IV)–(VI
)
(
XIV
)
2O
3
O
O
O O
O
O
O
3
O
COOH
XH
X
O
O
O
O
O
(
XV
)
(XIX)–(XXI)
3O
3
2O
3
peroxide products
of degradation
HOOC
HOOC
COOH
COOH
COOH HOOC
S
S
X
(
XVI)–(XVIII
)
(XIII)
Scheme 2.
By the second route, the decomposition of carꢀ
d[O3]
–ꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀꢀ = keff[ArCH3]o[O3]o,
dt
(1)
bocyclic ozonide XIV to give anthranilic (XIX), saliꢀ
cylic (XX), or thiosalicylic (XXI) acid depending on
the structure of the initial hetarene is possible, which
are intermediate products as in the case of ozonolysis
of benzo derivatives I–III. Carboxylic acids XIX–XXI
add about 3 mol of O3 each to form peroxide products
where keff is the effective rate constant of the reaction
of ozone with I–VI that takes into account all types of
interactions between the reactants, dm3/(mol s).
of degradation. As in the case of thionaphthene III
,
Ozone is likely consumed via a nonchain mechaꢀ
the products of ozonolysis of dibenzothiophene VI nism. Termination of ozone supply into the reaction
wee found to contain about 14% 2,2'ꢀdicarboxydipheꢀ mixture stops the oxidation. As can be seen from the
nylsulfide XIII, which can be formed through oxidaꢀ data in the table, fusion of the benzene ring to a fiveꢀ
tive condensation of intermediate thiosalicylic acid membered hetarene molecule leads to a reduction in
XXI, as confirmed by the IR data (Fig. 1). According the reactivity in the reaction with ozone to decrease in
to the data in the table, the overall experimental stoꢀ the reaction rate by a factor of 2 for
ichiometric coefficient of ozone exp is 5.61–5.64 mol to 5 for II and III. The annelation of another benzene
per mole of hetarenes IV–VI
I and a factor of 4
n
.
ting to the molecules of benzo derivatives I–III leads
to a further reduction in the rate of the ozone react ion
with IV–VI. The effective rate constant of the reaction
To gain further insight into the mechanism of the
reactions of interest, the kinetic features of the reacꢀ
tions of hetarenes I–VI with ozone in the medium of
glacial acetic acid at 290 K were studied. The reaction
kinetics was investigated by measuring the initial
ozone consumption rates at the reactor outlet in the
gas phase according to the procedure described in
[14]. The current concentration of ozone in the liquid
phase was determined with a Spektromomꢀ202 specꢀ
trophotometer using a gradientless catalytic shaker
reactor with respect to the gas phase.
of ozone regularly decreases in the order
I > II > III for
the benzo derivatives or IV VI for the dibenzo
>
V >
derivatives, which is strongly determined by the nature
of the heteroatom.
Thus, as a result of this study, it was shown that the
oxidation of benzo derivatives I–III with ozone in an
acetic acid solution involves as the fast electrophilic
attack of ozone across the double bond of heterocycle
with absorption of 1 mol of ozone per mol of substrate
It was found that the ozone uptake kinetics obeys and formation of ozonides in the first step followed by
the bimolecular rate law in the reactions with benzo the ozonide transformation via degradation of the hetꢀ
derivatives I–III (Fig. 2) and dibenzo derivatives IV– erocycle into intermediate benzaldehydes, which
VI (Fig. 3) to have the first order in each of the reacꢀ form peroxide compounds after the ozone attack at
tants:
the ꢀelectron system of the aromatic ring.
π
PETROLEUM CHEMISTRY Vol. 55
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REACTIONS OF BENZO AND DIBENZO DERIVATIVES
501
(а)
(b)
–log
3.1
W
–log
W
–log
4.1
W
–logW
1
1
3.7
3.5
3.3
3.1
4.7
4.5
4.3
4.1
2.9
2.7
2.5
3.9
3.7
3.5
2
2
–logCo 1.4 1.6 1.8 2.0
–log[O3]o
–logCo 1.4 1.6 1.8 2.0
–log[O ]
4.4 4.6 4.8 5.0
3 o 4.4 4.6 4.8 5.0
(c)
–log
5.0
W
–logW
1
5.1
4.9
4.7
4.5
4.8
4.6
4.4
2
–logCo 1.0 1.2 1.4 2.6
–log[O ]
3 o 4.4 4.6 4.8 5.0
Fig. 2. Dependence of the oxidation rate (
(b) II, (c) III in logarithmic coordinates at 290 K. VO = 3.3
W
) on the initial concentration of (
1
) benzo derivatives and (
2
)
) ozone: (a) I,
–3
3
–5
3
×
10 dm /s, (
1)
[О ] = 4.0
3 о
×
10 mol/dm , (
2
[ArH] = 1.0
×
о
2
–2
3
10 mol/dm .
(а)
(b)
–log
W
–log
W
–log
W
–logW
3.9
4.1
4.3
4.5
1
5.9
6.1
6.3
6.5
1
4.5
4.7
4.9
5.1
6.5
6.7
6.9
7.1
2
2
1.4
–logCo 1.4 1.6 1.8 2.0
–log[O ]
–logCo
1.6 1.8 2.0
–log[O ]
3 o 4.4 4.6 4.8 5.0
3 o 4.4 4.6 4.8 5.0
(c)
–log
W
–log
W
1
6.4
7.0
7.2
7.4
7.6
6.6
6.8
7.0
2
1.4
–logCo
1.6 1.8 2.0
–log[O ]
3 o 4.4 4.6 4.8 5.0
Fig. 3. Dependence of the oxidation rate (
(c) VI in logarithmic coordinates at 290 K. VO = 3.3
W
) on the initial concentration of (
1
) dibenzo derivatives and (
2
) ozone: (a) IV, (b)
V
×
,
–3
3
3
–5
3
×
10 dm /s, (
1
)
/с, [О ] = 4.0
3 о
×
10 mol/dm , (
2)
[ArH] = 1.0
о
2
2
3
10⎯ mol/dm .
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502
ANDREEV
3. L. Paquette, Principles of Modern Heterocyclic Chemisꢀ
It was also assumed that the ozonation of dibenzo
try (Benjamin–Cummins, New York, 1968).
4. A. R. Katritzky and J. M. Lagowski, Heterocyclic Chemꢀ
istry (Methuen, London, 1960).
5. M. A. Sukari and J. M. Vernon, J. Chem. Soc., Perkin
Trans., No. 9, 2219 (1983).
6. V. D. Komissarov, I. N. Komissarova, G. N. Farakhova,
and E. T. Denisov, Izv. Akad. Nauk SSSR, Ser. Khim.,
No. 6, 1205 (1979).
7. P. S. Bailey, Chem. Rev. 58, 925 (1958).
8. P. S. Bailey, Ozonation in Organic Chemistry, vol. 2:
Nonolefinic Compounds (Academic, New York, 1982).
9. B. Witkop, J. Am. Chem. Soc. 79, 3193 (1957).
10. P. Yu. Andreev, Russ. J. Appl. Chem. 85, 1395 (2012).
derivatives IV–VI involves at the first stage the attack
of ozone across the double bond of one of the carbocyꢀ
cles with absorption of 2 mol of ozone and formation
of diozonide, which is further transformed via two
routes resulting in peroxides and heterocyclic tetracarꢀ
boxylic acids.
The kinetics of ozone consumption in the reactions
with hetarenes I–VI follows the bimolecular rate law
and has the first order in each of the reactants.
The fusion of the benzene ring to the fiveꢀmemꢀ
bered hetarene molecules leads to a reduction in the
rate of reaction with ozone. The annelation of another
benzene ring into the molecule of benzo derivatives
leads to a further reduction in the reaction rate. The 11. P. Yu. Andreev, Ukr. Khim. Zh. 78 (8), 112 (2012).
effective rate constant of the reaction with ozone
decrease in the orders for II III and IV VI
12. N. M. Emanuel, Advances in Chemistry of Organic Perꢀ
oxide Compounds and Autooxidation (Khimiya, Mosꢀ
cow, 1969) [in Russian].
I
>
>
> V >
for the benzo and dibenzo derivatives, respectively.
13. V. P. Tsipenyuk, I. I. Bil’kis, V. A. Yakobi, and
S. M. Shein, Izv. Sib. Otd. Akad. Nauk SSSR, Ser.
Khim. Nauk, No. 6, 60 (1975).
REFERENCES
1. Heterocyclic Compounds, Ed. by R. C. Elderfield (Wiley, 14. Razumovskii, S.D. and Zaikov, G.E., Ozone and Its
New York, 1951), vol. 2.
2. J. Joule and G. Smith, Heterocyclic Chemistry (Van
Reactions with Organic Compounds (Nauka, Moscow,
19740 [in Russian].
Nostrand, London, 1972).
Translated by K. Aleksanyan
PETROLEUM CHEMISTRY Vol. 55
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2015