Hydroxylation of benzene in the system vanadium(V)-hydrogen peroxide-acetic acid

Article abstract of DOI:10.1134/S107036320609009X

Hydroxylation of benzene in acetic acid at 323 K was studied in the presence of a sodium orthovanadate catalyst. With hydrogen peroxide as aqueous solution, the yield of phenol was 12-14%. With hydrogen peroxide generated from dry sodium peroxide, the yield of phenol could be improved to 21-23%. The apparent decomposition rate constants of hydrogen peroxide in acetic acid are presented.

Full text of DOI:10.1134/S107036320609009X

ISSN 1070-3632, Russian Journal of General Chemistry, 2006, Vol. 76, No. 9, pp. 1407 1409.
Pleiades Publishing, Inc., 2006.
Original Russian Text
N.I. Rudakova, M.V. Klyuev, Yu.G. Erykalov, D.N. Ramazanov, 2006, published in Zhurnal Obshchei Khimii, 2006, Vol. 76,
No. 9, pp. 1466 1468.
Hydroxylation of Benzene
in the System Vanadium(V) Hydrogen Peroxide Acetic Acid
N. I. Rudakova, M. V. Klyuev, Yu. G. Erykalov, and D. N. Ramazanov
Ivanovo State University, ul. Ermaka 39, Ivanovo, 153025 Russia
e-mail: klyuev@ivanovo.ac.ru
Received October 2, 2005
Abstract Hydroxylation of benzene in acetic acid at 323 K was studied in the presence of a sodium
orthovanadate catalyst. With hydrogen peroxide as aqueous solution, the yield of phenol was 12 14%. With
hydrogen peroxide generated from dry sodium peroxide, the yield of phenol could be improved to 21 23%.
The apparent decomposition rate constants of hydrogen peroxide in acetic acid are presented.
DOI: 10.1134/S107036320609009X
Gekhman et al. [1] have reported the oxidation of
alkanes, isoalkanes, methyl carboxylates, and mole-
cular nitrogen in the system vanadium(V) hydrogen
peroxide acetic acid.
As mentioned above, the use of sodium peroxide
instead of aqueous hydrogen peroxide favors faster
1
formation of the oxidizing agent ( O ). Actually, it
2
can be suggested that in system B the reaction initially
occurs in a virtually nonaqueous medium. Under these
conditions, a stronger oxidant, acetyl hydroperoxide
AcOOH, can form rather than H O [scheme (3)].
In the present work we undertook an attempt to
apply the above system for hydroperoxide oxidation
2
2
(hydroxylation) of benzene. The expected reaction
product was phenol. Since the hydroxylation reaction
involves decomposition of hydrogen peroxide, we first
studied the kinetics of the latter reaction. The resulting
data are listed in Table 1.
H O + AcOH
AcOOH + H O.
(3)
2
2
2
H O + AcOOH
1O2 + H O + AcOH. (4)
2
2
2
The presence of water in the reaction medium
appears to disfavor formation of AcOOH, since equi-
librium (3) is shifted to the right.
In run nos. 1 13 (Table1), the reagent (H O ) was
2
2
introduced as a 33% aqueous solution, while in run
nos. 14 16 it was generated from dry sodium peroxide
according to scheme (1).
In the absence of sodium vanadate (run nos. 1 6),
the Kapp was (0.109 0.006) 10 4 s , whereas the
respective value in the presence of sodium vanadate
was (3.54 0.64) 10 4 s . Consequently, sodium
vanadate catalyzed the decomposition of hydrogen
peroxide.
1
Na O + 2AcOH
2AcONa + H O .
(1)
2
2
2 2
1
Thus, H O decomposition was actually studied in
2
2
two systems differing from each other in water con-
tent. System A: H O C H H O AcOH Na VO
2
2
6
6
2
3
4
1
0
2H O; initial concentration ratio 1.0:1.1:3.8:10.9:
.0054, respectively (Table 1, run nos. 1 13). System
Along with H O decomposition, benzene is hyd-
2
2
2
roxylated to form phenol. The yield of phenol in the
presence of iron catalysts can vary, depending on
conditions, from 20 30 [2, 3] to 60 80% [4, 5].
However, there is almost no information in the litera-
ture, concerning benzene hydroxylation in the pre-
sence of vanadium compounds.
B:
initial concentration ratio 1.0:1.0:8.3:2.0:0.005
H O C H AcOH AcONa Na VO 12H O;
2 2 6 6 3 4 2
(Table 1; run nos. 14 16).
As seen from Table 1, the rate of H O decomposi-
2
2
tion in system B that contains no water in the initial
reaction moment is 4 times higher than in system A
that initially contains water.
Our present study showed that vanarium(V) com-
pounds can catalyze benzene hydroxylation (Table 2).
Obviously, the higher yield of phenol is observed in
system B that initially contains sodium peroxide. The
yield of phenol attains 20 23% within 15 min (Ta-
ble 2, run nos. 6 9). At the same time, with aqueous
It is known [1] that H O2 decomposition in
2
aqueous AcOH occurs by scheme (2).
1
2
H O
2H O + O .
(2)
2
2
2
2
1407

1408
RUDAKOVA et al.
Table 1. Decomposition of hydrogen peroxide. Reagent concentrations, M: [H O ] = 1.25; [C H ] = 1.35; [H O] = 4.80;
2
2 0
6
6 0
2
0
[
[
AcOH] = 13.60; [Na VO 12H O] = 0.0067 (run nos. 11 13); [Na O ] = [C H ] = 1.36; [AcOH] = 11.32;
0 3 4 2 0 2 2 0 6 6 0 0
AcONa] = 2.7; [Na VO 12H O] = 0.0068 (run nos. 14 16)
0
3
4
2
0
4
1
Run no.
T, K
Reagent
H O
Time, min
H O , M
H O decomp., %
Kapp 10 , s
2
2
2 2
1
2
3
4
5
6
7
8
9
323
10
20
30
40
60
80
20
30
40
60
80
100
120
10
20
30
1.06
0.92
0.57
0.46
0.31
0.05
1.21
1.09
0.91
0.92
0.88
0.85
0.76
0.42
0.20
0.06
15.2
26.4
54.4
63.2
75.2
96.0
3.2
12.8
27.2
26.4
29.6
32.0
39.2
66.4
84.0
95.2
3.54 0.64
2
2
303
H O
0.74 0.06
2
2
10
11
12
13
14
15
16
a
323
Na O
16.2 1.8
2
2
a
Fast converts into H O by scheme (1).
2
2
Table 2. Yield of phenol, 323 K. Reagent concentrations, M: [H O ] = 1.25; [C H ] = 1.35; [AcOH] = 13.60;
2
2 0
6
6 0
0
[
H O] = 4.80; [Na VO 12H O] = 0.0067 (run nos. 1 5); [Na O ] = [C H ] = 1.36; [AcOH] = 11.32; [AcONa] =
2 0 3 4 2 0 2 2 0 6 6 0 0 0
2
.7; [Na VO4 12H O] = 0.0068 (run nos. 6 10)
3
2
0
Run. no.
Reagent
Time, min Yield of phenol, % Run no.
Reagent
Na O
Time, min Yield of phenol, %
1
2
3
4
5
H O
15
30
7.9
9.8
6
7
15
30
21.6
20.8
19.8
23.1
17.8
2
2
2
2
60
120
150
14.1
12.0
9.3
8
9
10
60
120
150
peroxide, the yield is 14% after 1 h. In the absence of
sodium vanadate, no phenol formed.
Hydroxylation of benzene. The catalyst solution,
20 ml, containing 0.05 10 3 mol of sodium ortho-
vanadate, 0.35 mol of AcOH, and 0.034 mol of
benzene were placed in a temperature-controlled flask
equipped with a mechanic stirrer and a reflux con-
The fact that the yield of phenol decreased at the
end of the reaction is natural and explained by further
transformations of phenol into dihydroxybenzene and
other oxidation products, as well as tar formation.
denser, after which 3 ml of H O (0.031 mol) as a
2
2
3
3% aqueous solution or finely ground sodium per-
In our opinion, the hydroxylation of benzene in the
system vanadium(V) Na O AcOH is of practical
oxide (0.034 mol) was slowly added. Samples of the
reaction mixture were taken at regular intervals. The
peroxide decomposition was followed by iodometry.
The yield of phenol was measured by GLC, internal
reference naphthalene, on a model 3700 gas chroma-
tograph (Russia), stainless-steel column (3 mm 1 m)
packed with 5% of XE-60 on Chezasorb AW (0.20
2
2
importance and deserves a more detailed study.
EXPERIMENTAL
The catalyst solution was prepared as described in
1]. Instead of ammonium metavanadate, finely
[
ground sodium orthovanadate, 340 mg, was intro-
duced into 100 ml AcOH, and the mixture was re-
fluxed for 5 h.
1
0.36 mm), carrier gas helium (1.8 lh ), flame ioniza-
tion detector, programmed oven temperature (initial
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 76 No. 9 2006

HYDROXYLATION OF BENZENE
vol. 45, no. 1, p. 45.
1409
temperature 130 C, final temperature 160 C, heating
rate 10 degmin ).
1
2
. Rudakova, N.I., Abstracts of Papers, Nauchnaya kon-
ferentsiya Nauchno-issledovatel’skaya deyatel’nost’ v
klassicheskom universitete: teoriya, metodologiya,
praktika (Scientific Conf. Research Activities in
Classical University: Theory, Methodology, Practice ),
Ivanovo, 2001, p. 189.
Sodium peroxide of pharmaceutic grade (main
substance content 75%) was used. The other reagents
were of no worse than pure grade and used as
received.
ACKNOWLEDGMENTS
3
4
. Rudakova, N.I. and Erykalov, Yu.G., Vestn. Ivanov.
Gos. Univ., 2003, p. 37.
The work was performed in the framework of the
Development of the Scientific Potential of High
School Program (project no. 2.2.1.1.7181) of the
Ministry of Education of the Russian Federation.
. Karakhanov, E.A., Narin, S.Yu., Fillipova, T.Yu., and
Dedov, A.T., Dokl. Akad. Nauk SSSR, 1987, vol. 292,
no. 6, p. 1387.
REFERENCES
1
. Gekhman, A.E., Stolyarov, I.P., Ershova, N.V., Moi-
5. Karakhanov, E.A., Narin, S.Yu., and Artemov, V.A.,
seeva, N.I., and Moiseev, I.I., Kinet. Katal., 2004,
Neftekhimiya, 1988, vol. 28, no. 3, p. 352.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 76 No. 9 2006