Catalytic oxidation of cyclohexane with ozone-oxygen mixtures

Article abstract of DOI:10.1023/B:RJAC.0000024575.94703.e8

Selective oxidation of cyclohexane with ozone in the presence of chromium(0) hexacarbonyl and sodium naphthenates-Cr(III) mixtures was studied.

Full text of DOI:10.1023/B:RJAC.0000024575.94703.e8

Russian Journal of Applied Chemistry, Vol. 77, No. 1, 2004, pp. 51 56. Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 1,
2004, pp. 54 59.
Original Russian Text Copyright
2004 by Syroezhko, Begak, Proskuryakov.
CATALYSIS
Catalytic Oxidation of Cyclohexane
with Ozone Oxygen Mixtures
A. M. Syroezhko, O. Yu. Begak, and V. P. Proskuryakov
St. Petersburg State Technological Institute, St. Petersburg, Russia
Mendeleev Russian Research Institute of Metrology, Federal State Unitary Enterprise, St. Petersburg, Russia
Received March 20, 2003
Abstract Selective oxidation of cyclohexane with ozone in the presence of chromium(0) hexacarbonyl and
sodium naphthenates Cr(III) mixtures was studied.
Since cyclohexane is an intermediate of caprolac-
tam oxidation, an increase in the selectivity of cyclo-
hexane oxidation to cyclohexanone [1] is an urgent
problem.
tures. The kinetics of the overall cyclohexane con-
sumption is of the first order irrespective of the cata-
lyst (Figs. 2, 3). This is confirmed by the constancy of
the accumulation rates of cyclohexanol, cyclohexa-
none, cyclohexyl hydroperoxide, and the acids in
cyclohexane ozonolysis in the presence of cobalt(II)
stearate (Fig. 1). Hence, the selectivity of formation of
the target product (cyclohexanone) is almost constant
Previously we showed [2] that noncatalytic oxida-
tion of cyclohexane to cyclohexanone with ozone is
more selective that industrial oxidation of cyclohexane
with atmospheric oxygen to form a mixture of cyclo-
hexanol and cyclohexanone.
(b)
(a)
c, M
The selectivity of oxidation of alkanes and cyclo-
alkanes to the corresponding carbonyl compounds
appreciably increases in the presence of catalysts of
heterolytic decomposition of hydroperoxides, such as
chromium(III) and chromium(VI) compounds [3 5].
The catalytic effect in the course of high-temperature
liquid-phase oxidation of alkanes and cycloalkanes in
manifested mainly in the step of hydroperoxide de-
composition. When the process is performed at low
temperature in the presence of a strong oxidizing
agent (O and O ), variable-valence metal compounds
can appreciably affect the mechanism of chain initia-
tion, propagation, and termination and the contribu-
tion of radical and nonradical pathways. To control
the selectivity of these processes, the features of the
mechanism of these steps should be determined.
, h
, h
Fig. 1. Kinetic curves of accumulation of (1) cyclohexa-
none, (2) cyclohexanol, (3) cyclohexyl hydroperoxide,
(4) acids, and (5) esters in catalytic oxidation of cyclo-
hexane with ozone in the presence of (a) Cr(CO) and
(b) Co(St) . 40 C, [O ] = 4 vol %, [cat] = 2 10 M; the
3
2
6
4
2
3
same for Fig. 2. (c) Concentration of reaction product and
( ) time.
ln(c/c0)
The procedures for oxidizing cyclohexane and for
analyzing the reaction products were described pre-
viously [2, 3].
Cyclohexane ozonolysis was performed at 20
60 C in the presence of 2 10 2 10 M stearates,
naphthenates, and acetylacetonates of Co(II), Co(III),
2
3
, h
Fig. 2. Kinetic curves of cyclohexane consumption. (c ,
0
c) Initial and current cyclohexane concentrations and
( ) time; the same for Fig. 3. (1) Cr(CO) ; (2) Co(acac) ;
Cr(III), Mn(II), and Cr(CO) as catalysts. The typical
6
6
6
2
kinetic curves of accumulation of the oxidation prod-
ucts are shown in Fig. 1. The classes of compounds
formed in this reaction are identical to those formed
in oxidation of cyclohexane with ozone oxygen mix-
5
(3) no catalyst; (4) Cr(St) ; (5) [Cr(CO) ] = 2 10 M;
3
2
(6) Mn(acac) ; (7) Co(St) ; (8) Cr(CO) , [O ] = 3 vol %;
(9) Cr(CO) , [O ] = 2 vol %; (10) cyclohexane; and
3
6
3
6
3
4
(11) cyclohexanol ([Cr(CO) ] = 2 10 M).
6
1070-4272/04/7701-0051 2004 MAIK Nauka/Interperiodica

52
SYROEZHKO et al.
course of cyclohexane ozonolysis is low owing to its
ln(c/c0)
fast consumption in the reaction with ozone (catalysis
of this reaction is possible). The inhibiting effect is
most likely due to reaction of the peroxy radicals with
the catalyst. The rate constant of the reaction between
the peroxy radicals and 3d-metal compounds is high
[6]. The catalysis with Cr(CO) and Co(acac) can be
6
3
, h
Fig. 3. Kinetic curves of cyclohexane consumption {[O ] =
related to their reaction with ozone, cyclohexane, and
its oxidation products.
3
5
3
2 4 vol %; [Cr(CO) ] = 2 10
(1 9) 4 and (10, 11) 20. T, C: (1 3, 7 10) 60 and (4 6,
2 10 M}. [O ], vol %:
6
3
The selectivity of cyclohexanone formation is
3
4
11) 2. [Cr(CO) ], M: (1, 6, 7) 2 10 , (2, 5, 8, 11) 2 10 ,
maximal in the presence of Cr(CO) . We studied the
6
6
5
rate and selectivity of cyclohexane ozonolysis as
influenced by the temperature, ozone concentration,
and catalyst. The apparent activation energies of the
overall cyclohexane consumption and cyclohexanone
formation, determined by varying the reaction tem-
perature in the range 20 60 C, are 34.5 3 and 27.5
(4, 9) 2 10 , and (3, 10) 0.
i, %
(a)
1
2.5 kJ mol , respectively, and are close to those of
the noncatalytic process. The noticeable difference in
the activation energies under conditions of consecu-
tive and parallel reactions suggests a strong tempera-
ture effect on the reaction selectivity, which is con-
firmed experimentally (Figs. 4a, 4b).
ci, M
i, %
(b)
The experimental kinetic curves measured at dif-
ferent concentrations of ozone and the catalyst and at
different temperatures are shown in Figs. 2 and 3,
respectively. The ozone concentration and the tem-
perature have the strongest effect on the reaction rate.
As the ozone concentration increases by a factor of 2
(from 2 to 4 vol %), the cyclohexane consumption ac-
ci, M
of formation of cyclohexane
celerates by a factor of 2.4 {20 C, [O ] = 2 4 vol %,
Fig. 4. Total selectivity
3
i
4
[Cr(CO) ] = 2 10 M}. Hence, bimolecular non-
oxidation products as a function of cyclohexane conversion.
6
4
40 C; [O ] = 4 vol %; (a) [Cr(St) ] = 2 10 and (b)
chain reaction of cyclohexane with ozone [1] is ac-
companied by chain oxidation of cyclohexane or de-
composition of ozone with acceleration of initiation
and progress of cyclohexane ozonolysis. The depen-
dence of the rate of cyclohexane (RH) oxidation with
ozone in CCl at 22 C on [RH], [O ], and [O ] is
3
3
4
[Cr(CO) ] = 2 10 M. ( c ) Total concentration of the
6
i
oxidation products.
in the examined conversion range ( 10%). In the
presence of Cr(CO) , the accumulation rates of the
6
4
3
2
hydroperoxide, alcohol, and ketone are also constant
in the first oxidation steps (Figs. 1 3). The kinetic
curve of accumulation of the acids is nonlinear. How-
ever, since the content of these acids in less than
0.05 M, the contribution of this pathway is insig-
nificant and has small effect on the kinetic curve of
cyclohexane consumption.
described by the equation [7]
3
v = 3.2 10 [RH][O3] + 0.3[RH]1/2[O3]3/2
+ 0.75[RH][O3]2/[O2]gas
.
The third component of this equation is responsible
for chain decomposition of O [7] under the action of
cyclohexyl radicals. The chain propagates by the
Chromium hexacarbonyl catalyzes the oxidation,
whereas CoSt , Mn(acac) , and CrSt appreciably
3
2
3
3
equation R + O
R and is terminated by the reaction R + O
provided that the reaction between two cyclohexylper-
RO + O , RO + RH
ROH +
inhibit the cyclohexane ozonolysis. Clearly, this is not
due to homolytic or heterolytic catalytic decomposi-
tion of cyclohexyl hydroperoxide. First, at 20 40 C
cyclohexyl hydroperoxide is relatively stable to ther-
mocatalytic decomposition [4, 5]. Second, the steady-
state concentration of cyclohexyl hydroperoxide in the
3
2
RO
2
2
oxy radicals is faster than the reaction of RO with
2
ozone. In this case (no solvent, bubbling reactor,
[RH] >> [O ] [O ]), cyclohexyl radicals are almost
3
2
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 77 No. 1 2004

CATALYTIC OXIDATION OF CYCLOHEXANE
53
quantitatively oxidized to cyclohexylperoxy radicals.
However, in the first steps of cyclohexane ozonolysis
[7], the major oxidation product, cyclohexanol, is
rapidly converted into cyclohexanone by the nonchain
mechanism. The reaction of cyclohexylperoxy radicals
with ozone and quadratic chain termination with the
peroxy radicals should be taken into account in the
kinetic equation of cyclohexane consumption by the
chain mechanism. The experimental kinetic curves of
case, the ketone yield is as high as 70% at 6.5% con-
version. When chromium(III) acetate poorly soluble
in the reaction mixture is used, the selectivity of the
ketone formation does not exceed 31%, but the selec-
tivity of the hydroperoxide formation reaches 48%.
The catalytic effect of ozone CoSt , ozone
2
Co(acac) , and ozone Mn(acac) systems on the selec-
3
3
tivity is considerably lower than that of the ozone
chromium(III) and ozone chromium(0) systems. In
cyclohexane consumption in ln(c/c )
coordinates
0
the presence of Mn(acac) , cyclohexane is rapidly
3
(c and c are the initial and current cyclohexane con-
0
converted into the acids and -caprolactone and the
total yield of peroxides grows with increasing cyclo-
hexane conversion. This dependence passes through
a maximum.
centrations, respectively; is the reaction time), meas-
ured in the first reaction step at low cyclohexane con-
version (up to 8%) and small contribution of the chain
pathway, are almost linear (Figs. 2, 3). The effect
Although the selectivity of cyclohexanone forma-
of Cr(CO) concentration is significantly weaker.
6
6
5
3
tion is maximal in the presence of the ozone Cr(CO)
As [Cr(CO) ] increases from 2 10 to 2 10
M
6
catalytic system, the selectivity and rate of the reac-
tion considerably change in the examined tempera-
ture range (20 60 C). Cyclohexane ozonolysis with
ozone air mixtures containing 2% ozone is slow.
In 4 h, the hydrocarbon conversion is as low as 2.2%,
and the selectivity of cyclohexanone formation reaches
42 51%. Under these conditions, the catalyst affects
the ratio of the main classes of the ozonolysis prod-
ucts. The selectivity of the cyclohexanone formation
(20 60 C), the rate of cyclohexane consumption
increases by more than 30% as compared to the non-
catalytic reaction. As shown above, the mechanism of
ozonolysis of saturated hydrocarbons is radical chain.
Catalytic oxidation of cyclohexane with ozone
occurs also by the radical chain pathway. To gain in-
sight into the mechanism of this process, we studied
accumulation of the main reaction products. To deter-
mine the influence of various catalysts [mainly
5
in the presence of 2 10 M Cr(CO) is relatively
6
Cr(CO) ] on the yield of each product, we measured
6
high (up to 65%). The total yield of the hydroper-
oxides slightly grows with increasing catalyst concen-
tration.
the dependence of the selectivity of its formation on
the hydrocarbon conversion. The reaction selectivity
was taken as the ratio of the concentration of a defi-
nite reaction product to the total concentration of
the reaction products.
This is the case at elevated temperatures (60 C).
Under these conditions, the selectivity of cyclohexa-
none formation is no higher than 60%. At 60 C, the
conversion of cyclohexanol and cyclohexyl hydroper-
oxide into cyclohexanone and parallel conversion
of cyclohexanone into the acids and lactone are ac-
celerated. The almost optimal conditions of catalytic
The dependences of the total selectivity of forma-
tion of each product on the hydrocarbon conversion in
catalytic ozonolysis of cyclohexane at [O ] = 4 vol %,
3
4
40 C, and the catalyst concentration of 2 10
M
are shown in Figs. 4a and 4b. As the conversion in-
creases, the selectivity of formation of the hydroper-
oxide and cyclohexanol linearly decreases, as a rule,
and that of cyclohexanone formation increases owing
to conversion of cyclohexanol and cyclohexyl hydro-
peroxide into the ketone. When the conversion is
lower than 10%, the selectivity of cyclohexanone for-
mation ranges from 69 to 73% without catalyst and
ozonolysis of cyclohexane are as follows: [O ] =
3
4
4 vol %, 40 C, [Cr(CO) ] = 2 10 M, cyclohexane
6
conversion 7 10%. The ketone yield reaches 81%.
Ozone sodium naphthenate, chromium(III) naphthe-
nate, and ozone chromium(III) naphthenate catalytic
systems [8, 9] provide 85 90% selectivity of the
ketone formation at the cyclohexane conversion of
5.3 6.5%.
reaches 81% in the presence of Cr(CO) . In addition,
6
Thus, as the cyclohexane conversion increases, the
selectivity of formation of the main reaction products
(R C=O, ROOH, and ROH) is constant, decreases, or
increases depending on the reaction conditions (tem-
perature, concentrations of ozone and the catalyst). At
low temperature (20 C), the selectivity of formation
of these products decreases with increasing ozone
in the presence of Cr(CO) , the yield of cyclohexyl
6
hydroperoxide and cyclohexanol decreases more
sharply with increasing cyclohexane conversion.
Hence, Cr(CO) catalyzes the conversion of these
6
compounds into cyclohexanone. An ozone chromi-
um(III) stearate system also exhibits high catalytic ac-
tivity with respect to cyclohexanone (Fig. 4a). In this
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 77 No. 1 2004

54
SYROEZHKO et al.
concentration owing to acceleration of the consump-
tion of the alcohol and hydroperoxide. The selectivity
of the ketone formation grows with increasing cyclo-
hexane concentration. At 60 C, cyclohexanone oxida-
tion is accelerated and the selectivity of its formation
remains constant in the whole examined conversion
range. The selectivity of formation of acids and esters
increases. In the course of cyclohexane ozonolysis
hydrotrioxide, cyclohexanol, cyclohexyl hydroperox-
ide, and RO radical [1].
2
Let us consider the influence of Cr(CO) catalyst
6
on the conversion of the above intermediates of cyclo-
hexane ozonolysis. In the presence of chromium com-
pounds, cyclohexyl hydroperoxide is selectively con-
verted into cyclohexanone mainly by the nonradical
mechanism [4]. Indictor et al. showed [5] that Cr(III)
is oxidized with the hydroperoxide to Cr(VI). Anto-
novskii suggests [13] that the O O bond of the peroxy
ester is homolytically ruptured to form the ketone
at 40 C in the presence of the ozone Cr(CO) catalyt-
6
ic system, the total selectivity of cyclohexanone for-
mation regularly increases, the selectivity for the hy-
droperoxide and alcohol decreases, and the selectivity
for the acids is constant. In the presence of ozone
,
,
,
L3(RO2)2Cr
O
O
C
L3(RO)2CrOH + C=O.
,
NaNph Cr(Nph) (Nph is the naphthenate anion) cata-
3
lytic system, the total selectivity of formation of
cyclohexanol and cyclohexanone mixture is high [10].
To gain deeper insight into the mechanism of cyclo-
hexane oxidation, let us consider the transformation of
the catalyst, hydroperoxide, alcohol, and ketone under
these conditions.
H
As found in [4], decomposition of tert-butyl hy-
droperoxide in the presence of Cr(III) acetylacetonate
is described by the scheme
Cr(III) + yt-BuOOH
Complex Cr(III+ l) + y(t-BuO + OH),
Cr(III+ l) + Cr(III) Cr(VI) + Cr(l),
Complex,
The rate constant of reaction of ozone with Co(II),
Fe(II), Mn(II), and Cr(III) acetates is higher by 2
3 orders of magnitude than that of reaction of ozone
with cyclohexyl hydroperoxide [1, 3, 11]. Ozone
reacts with the catalysts by the reaction [12]
where y is the stoichiometric coefficient, and l is
an integer equal to the change in the chromium oxida-
tion state.
O3 + M(II)
M(III) + O2 + O (or O3).
Negatively charged oxygen atom rapidly reacts
with a proton of the acid present in the reaction mix-
ture to form OH radical. In addition, the reaction of
a saturated hydrocarbon with ozone [1] yields R and
OH radicals. Hydroxy radicals oxidize the reduced
form of a variable-valence metal:
Bibichev [14] also suggests that the selective con-
version of a secondary hydroperoxide into the ketone
in the presence of chromium(III) stearate also passes
through formation of the complex Cr(St) nROOH,
3
where n > 1. When a hydroperoxide molecule is coor-
dinated to the Cr(III) atom, the electron density from
the -oxygen atom of the hydroperoxide is transferred
to the d orbital of Cr(III). As a result, the O O bond
of the hydroperoxide is weakened and then homo-
lytically ruptured to form alkoxy and hydroxy radicals.
The liberated OH radical, without escaping into the
bulk of solution, can attack the C H bond of the
coordinated hydroperoxide to form the ketone and
water by the molecular (cryptoradical) mechanism.
.
OH + M(II)
M(III) + OH.
The oxidation potential of Me(III)/Me(II) is suffi-
cient for Me(III) to oxidize hydroperoxides, al-
cohols, and ketones. If the activation energy of the
reaction of the initial or intermediate compound with
the oxidized form of the catalyst is high, more active
OH radical can initiate the oxidation. In addition, in
the course of cyclohexane oxidation with an ozone air
mixture, variable-valence metal carboxylates in the
oxidized or reduced forms coordinate the oxygen-con-
taining reaction products (ROOOH, ROH, R C=O).
The overall rate of catalytic ozonolysis of cyclohexane
should depend on the stability of these complexes,
and the selectivity of ketone formation, on the ratio
of the rates of formation and consumption of these
complexes. The main sources of cyclohexanone in
noncatalytic ozonolysis of cyclohexane are unstable
The apparent rate constant of cyclohexyl hydroper-
4
oxide decomposition in the presence of 2 10
M
7
1
Cr(CO) is 7.6 10 exp( 67000 2000)/RT min .
6
If the steady-state concentration of ROOH is 0.1 M,
the rate constant of cyclohexanone formation from
1
1
hydroperoxide at 40 C is 0.0046 mol l h . Hence,
the contribution of the catalytic decomposition of
cyclohexyl hydroperoxide to cyclohexanone formation
is no higher than 2 and 8.2% at 40 and 60 C, respec-
tively, i.e., is low.
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 77 No. 1 2004

CATALYTIC OXIDATION OF CYCLOHEXANE
Cr(V) + O3
55
The steady-state concentration of hydrotrioxide at
Cr(VI) + O ,
ROOH.
3
O
2
20 C is 2.2 10 M. The strength of the O O bond
in this compound is close to that in cyclohexyl hydro-
peroxide. Hence, the contribution of the catalytic
decomposition of the hydrotrioxide to the overall
process can be neglected. Both inner- and outer-sphere
coordination of cyclohexyl hydroperoxide is typical of
3d transition metals [15]; however, coordination-
RO2 + H+
It is known [20] that Cr(VI) selectively oxidizes
alcohols to carbonyl compounds:
Cr(VI) + ROH
R=O + Cr(IV).
saturated Cr(CO) can form only outer-sphere com-
6
plexes with ROOH [Cr(CO) ROOH]. Chromium
hexacarbonyl is stable up to 120 140 C. Since car-
bonyl groups in Cr(CO) are substituted by the dis-
sociative mechanism with a high activation energy
( E = 163 kJ mol ), occurrence of these reactions
under our conditions is unlikely.
6
Probably, Cr(IV) is reduced to Cr(III) with cyclo-
hexanol hydroxy hydroperoxide or the hydroxyperoxy
6
OH
.
OO
1
a
radical
exhibiting redox properties [6]. In addi-
Carbonyl ligands are strongly bonded to the chro-
tion, reactions between chromium atoms in different
oxidation states are also possible. The steady-state
concentration of cyclohexanol in the products of cata-
lytic ozonolysis of cyclohexane is low (Fig. 4). The
cyclohexanol yield in the course of the ozonolysis
decreases owing to its conversion into cyclohexanone
[21, 22].
mium atom in Cr(CO) . The donor acceptor bond in
6
carbonyls is formed by interaction of the d orbital of
2
2
the metal, e.g., d
, with n electrons of CO on the
x
y
sp-hybrid
orbital. The carbonyl group donates the
n
-electron pair localized on the carbon atom. The
dative bond in carbonyls is formed by donation of
the electron density form d orbitals of the metal, e.g.,
Probably, the fact that the total yield of cyclohexa-
nol and cyclohexanone and the concentration ratio of
these products vary a wide range (Fig. 4) is due not
only to the catalysis of the alcohol oxidation to the
ketone with Cr(VI). Special experiments show slow
consumption of cyclohexanol and cyclohexanone in
the course of cyclohexane ozonolysis catalyzed with
d , to unoccupied antibonding
orbitals of CO.
xy
However, zero-valent chromium in Cr(CO) is
6
rapidly oxidized with ozone to Cr(III) and Cr(VI).
A sharp band at 336 nm typical for Cr(III) appears in
the electronic absorption spectra of Cr(CO) solutions
6
3
in CHCl and cyclohexane (1.2 10 M) after bub-
3
Cr(CO) in a bubbling reactor. Slow consumption of
6
bling of an ozone oxygen mixture for 0.5 1 min
cyclohexanol is caused by its self-accociation. We
suggest that the increased cyclohexanol yield in the
presence of chromium-containing catalysts is due to
a change in the reactivity of the peroxide and alkoxy
radicals in the chromium(III) coordination sphere. The
transformations of these radicals in the course of
cyclohexane ozonolysis are discussed in [1].
([O ] = 4 vol %, 25 C). As determined by ESR, the
3
5+
steady-state concentration of Cr [18] is very low.
Hexavalent chromium was qualitatively determined by
the reaction with diphenylcarbazide [19].
The overall process of Cr(CO) oxidation with
6
ozone can be described by the following reactions:
Cr(CO)6 + mO3
Cr(III)L3 + 3O ,
CONCLUSION
CO, CO2, O2
Ozone chromium(0) hexacarbonyl, ozone chromi-
um(III) naphthenate sodium naphthenate, and chromi-
um(0) hexacarbonyl cyclohexyl hydroperoxide sys-
tems are catalytically active in cyclohexane oxidation.
In the presence of these catalysts, the selectivity of
formation of cyclohexanol cyclohexanone mixture
and of the target product, cyclohexanone, is high.
K
e
O
+ H+
OH,
Ke = 1012 [3],
.
OH + Cr(III)
OH + H+
Cr(IV) + OH,
H2O,
.
Cr(III) + RO2
Cr(IV) + RO2,
Cr(V) + O + O2,
Cr(IV) + O + O2,
REFERENCES
Cr(IV) + O3
Cr(III) + O3
1. Tedder, J.M., Nechvatal, A., and Jubb, A.H., Basic
Organic Chemistry, London: Wiley, 1975.
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 77 No. 1 2004

56
SYROEZHKO et al.
2. Syroezhko, A.M., Proskuryakov, V.A., and Be-
13. Antonovskii, V.L., Organicheskie perekisnye initsia-
tory (Organic Peroxide Initiators), Moscow: Khimiya,
1972.
gak, O.Yu., Zh. Prikl. Khim., 2002, vol. 75, no. 9,
pp. 1480 1484.
3. Syroezhko, A.M., Liquid-Phase Oxidation of Alkanes,
Cycloalkanes, and Their Oxygen-Containing Deriva-
tives with Oxygen and Ozone in the Presence of s-
and 3d-Element Compounds, Doctoral Dissertation,
Leningrad, 1984.
4. Pustarnakova, G.F., Solyanikov, V.M., and Deni-
sov, E.T., Izv. Akad. Nauk SSSR, Ser. Khim., 1975,
no. 3, pp. 547 552.
5. Indictor, N., Yochsberger, T., and Kurnit, D., J. Org.
Chem., 1969, vol. 34, no. 10, pp. 2855 2861.
6. Denisov, E.T. and Kovalev, G.I., Okislenie i stabiliza-
tsiya reaktivnykh topliv (Oxidation and Stabilization
of Propellants), Moscow: Khimiya, 1983.
14. Bibichev, V.M., A Study of Liquid-Phase Oxidation of
n-Paraffins to Acids in the Presence of Multicompo-
nent Catalysts, Cand. Sci. Dissertation, Leningrad,
1979.
15. Yablonskii, O.P., Complexation and Its Role in Oxida-
tion and Separation of Hydrocarbons, Doctoral Dis-
sertation, Ivanovo, 1979.
16. Makashev, Yu.A. and Zamyatkina, V.M., Soedineniya
v kvadratnykh skobkah (Compounds in Brackets),
Moscow: Khimiya, 1976.
17. Skorik, N.A. and Kumok, V.N., Khimiya koordina-
tsionnykh soedinenii (Coordination Chemistry), Mos-
cow: Vysshaya Shkola, 1975.
7. Denisov, E.T., Inogi Nauki Tekh., Ser.: Kinet. Katal.,
18. Popova, N.M and Sokol’skii, D.V., Glubokoe kataliti-
cheskoe okislenie uglevodorodov (Problemy kinetiki
i kataliza) (Exhaustive Catalytic Oxidation of Hydro-
carbons (Problems of Kinetics and Catalysis)), Mos-
cow: Nauka, 1981, vol. 18, pp. 133 142.
1981, vol. 9.
8. Bibichev, V.M., Syroezhko, A.M., and Svir-
kin, Yu.Ya., in Issledovanie v oblasti khimii i tekhno-
logii produktov pererabotki goryuchikh iskopaemykh
(A Study in the Field of Chemsitry and Technology of
Reprocessing Products of Fossil Fuels), Leningrad:
Leningr. Tekhnol. Inst. im. Lensoveta, 1980,
pp. 99 102.
19. Marczenko, Z., Kolorymetryczne oznaczanie pier-
wiastkow, Warsaw: Wydawnictwa Naukowa-Tech-
niczne, 1968.
9. USSR Inventor’s Certificate no. 692826.
20. Candlin, J.P, Taylor, K.A., and Thompson, D.T.,
Reactions of Transition Metal Complexes, Amster-
dam: Elsevier, 1968.
10. Korotkova, N.P., Syroezhko, A.M., and Proskurya-
kov, V.A., Zh. Prikl. Khim., 1981, vol. 54, no. 4,
pp. 885 889.
11. Rakovski, S.K., Chernyaeva, D.F., and Shopov, D.N.,
Izv. Akad. Nauk SSSR, Ser. Khim., 1979, no. 9,
pp. 1991 1995.
21. Yakovlev, A.S., Syroezhko, A.M., Vikhorev, A.A.,
and Proskuryakov, V.A., Izv. Vyssh. Uchebn. Zaved.,
Khim. Khim. Tekhnol., 1983, vol. 1, no. 3, pp. 122
124.
22. Semenchenko, A.E., Solyanikov, V.M., and Deni-
sov, E.T., Kinet. Katal., 1972, vol. 13, no. 5,
pp. 1153 1159.
12. Gorbenko-Germanov, D.S., Neorganicheskie perekis-
nye soedineniya (Inorganic Peroxides), Moscow:
Nauka, 1975.
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