Oxidative carbonylation of benzene and toluene catalyzed by compounds of Pd or Rh in trifluoroacertic acid and its anhydride in the presence of Cu, Fe, V, or Mo compounds, with oxygen as an oxidant

Article abstract of DOI:10.1023/A:1013922523320

Oxidative carbonylation of benzene and toluene catalyzed by Pd or Rh compounds in the presence of Cu, Fe, V, or Mo compounds in a mixture of trifluoroacetic acid and its anhydride at 125-150°C and partial pressures of carbon monoxide of 0.6-4.7 MPa and oxygen of 0.2-0.8 MPa leads to the corresponding aromatic acids with the yields of up to ca. 50% and 1800 mol per g-atom of the platinum group metal which is tens times higher than that achievable in the absence of oxygen. With the use of IR spectroscopy in situ it was shown that an acyl complex of Pd is formed, and the possibility of determination of the oxidation state of the cation of Cu in the course of oxidative carbonylation was demonstrated.

Full text of DOI:10.1023/A:1013922523320

Russian Journal of General Chemistry, Vol. 71, No. 9, 2001, pp. 1463 1466. Translated from Zhurnal Obshchei Khimii, Vol. 71, No. 9, 2001,
pp. 1545 1548.
Original Russian Text Copyright
2001 by Kalinovskii, Gel’bshtein, Pogorelov.
Oxidative Carbonylation of Benzene and Toluene Catalyzed
by Compounds of Pd or Rh in Trifluoroacertic Acid
and Its Anhydride in the Presence of Cu, Fe, V,
or Mo Compounds, with Oxygen as an Oxidant
I. O. Kalinovskii, A. I. Gel’bshtein, and V. V. Pogorelov
State Research Center of Russian Federation
Karpov Research Physico-Chemical Institute, Moscow, Russia
Moscow State University, Moscow, Russia
Received February 16, 2000
Abstract Oxidative carbonylation of benzene and toluene catalyzed by Pd or Rh compounds in the
presence of Cu, Fe, V, or Mo compounds in a mixture of trifluoroacetic acid and its anhydride at 125 150 C
and partial pressures of carbon monoxide of 0.6 4.7 MPa and oxygen of 0.2 0.8 MPa leads to the corres-
ponding aromatic acids with the yields of up to ca. 50% and 1800 mol per g-atom of the platinum group metal
which is tens times higher than that achievable in the absence of oxygen. With the use of IR spectroscopy in
situ it was shown that an acyl complex of Pd is formed, and the possibility of determination of the oxidation
state of the cation of Cu in the course of oxidative carbonylation was demonstrated.
The reaction of oxidative carbonylation of aromatic
compounds is a single-step method of synthesis of
various aromatic acids [1]. The use of molecular
oxygen as an oxidant makes the reaction (1) potential-
ly suitable for wide-scale industrial implementation.
30%, and was as high as 60 mol per g-atom of Rh at
150 C with the sum of partial pressures of carbon
monoxide and oxygen equal to 27.6 MPa. With the
use of similar catalytic systems based on Rh or Pd
compounds and Cu in a mixture of CF3COOH and
(CF3CO)2O at 110 160 C by way of variation of re-
action (1) conditions with partial pressures of 0.2
2.9 MPa and 0.3 1 MPa, respectively, the obtained
yield of ArCOOH was about 700 mol per g-atom of
Rh which is ca. 30 as high as the largest possible
yield in the absence of oxygen [7].
ArH + CO + 1/2O2
ArCOOH.
(1)
It is believed that in the oxidative carbonylation of
arenes oxidized forms of platinum group metals are
the active catalytic species [2]. Each act of formation
of the reaction product is attended with the reduction
of the cation of the platinum group metal, and so there
arises the necessity of its reoxidation [3]. However,
compounds of the platinum group metals in their
lower oxidation states are oxidized by molecular
oxygen at an inadequate rate, and high yilds of the
target products basing on the loaded catalyst can not
be achieved [1]. So, analogously to the Wocker
process [4, 5], it is necessary to make compounds of
some other transition metal, copper [6] as an example,
a part of the catalytic system. Copper compounds can,
on the one hand, effectively oxidize the reduced forms
of the platinum group metal and, on the other hand,
can be reoxidized by oxygen at a rather high rate.
Instead of copper compounds, Fe(III), V(V), and
Mo(VI) compounds were also used as oxidizers in the
reactions catalyzed by palladium compounds [8, 9].
Their values of redox potentials [4, 8] gave grounds to
believe that the process of reoxidation of their reduced
forms by molecular oxygen will proceed at a rate high
enough for effecting reaction (1).
Experimetally, it turned out that in the case of
oxidative carbonylation of benzene in the presence of
Pd compounds (see the table) the catalytic systems
based on Fe, V, and Mo compounds (runs nos. 3 5)
exhibit higher activity, but lead to the yields of the
same order as those containing Cu compounds (runs
In [6] it was demonstrated that toluene, in principle, nos. 1 and 2). It should be noted, however, that com-
can be involved in reaction (1), because in one of the
experiments the yield of p-toluic acid exceeded that
paring of various catalytic systems under the condi-
tions of preparative runs is not fully correct since even
theoretically achievable in the absence of oxygen by when the reaction conditions are scrupulously
1070-3632/01/7109-1463$25.00 2001 MAIK Nauka/Interperiodica

1464
KALINOVSKII et al.
Oxidative carbonylation of benzene catalyzed by Pd
compounds in the presence of Cu, Fe, V, and Mo com-
poundsa
85% as its yield in run no. 6. Increasing pCO from 1.6
up to 2.0 MPa has little effect on the yield of
PhCOOH (runs nos. 6 and 8). Moreover, from runs
nos. 10 and 11 it follows that pCO can be raised up to
ca. 5 MPa with the acceptible parameters of reac-
tion (1) process which allows the use of non-explosive
CO and O2 mixtures containing ca. 5% of O2. High
dilution of the gas mixture with nitrogen (run no. 12)
did not lead to a substantial decrease in the reaction
Yield of
benzoic acidb
Cu, V, and Mo
pCO, pO ,
Run
no.
2
compounds, mol
mol
per
MPa MPa % of
taken
number 105
g-atom rate which means that air can be used as a source of
benzene
of Pd
190
oxygen in reaction (1). From run no. 12 it follows that
(CF3CO)2O which in some cases increases the reac-
tion (1) rate [10] is not the necessary component of
the catalytic systems.
1c
2c
Cu(O2CCH3)2 H2O, 1.6 0.4
13.5
4
7
Cu(O2CCF3)2 (I),
30
1.6 0.4
300
In distinction to oxidaive carbonylalation of arenes
with the use of MnO2 as an oxidizer [2] under the
conditions of reaction (1), reoxidation of 1 mol of
Pd(0) complex, as it follows from equatition (2), leads
to the formation of not 2, but 1 mol of water. The
formed water is completely consumed in hydrolysis
(3) of the reaction product, compound anhydride
ArCOO2CCF3 [2, 7], so no accumulation of water
which deactivates the catalytic system [2] takes place
in the reaction mixture.
3
4
V2O5 (II), 21.7
FeC2O4 2H2O
(III), 13.5
1.6 0.4 22 (32)
970
550
1.6 0.4
12
5
6
(NH4)6Mo7O24
4H2O, 6.9
(II), 21.7; (III),
1.5 0.3
32
1630
1800
1.6 0.4 41 (59)
13.5
7d (II), 25; (III), 13.5 1.6 0.4 53 (89)
1090
1620
1550
8
9
(II), 20; (III), 13.5 2.0 0.4
38
(II), 21.7; (III),
1.6 0.8 35 (73)
Pd(0) + 2CF3COOH + 1/2O2 = Pd(O2CCF3)2 + H2O, (2)
ArCOO2CCF3 + H2O = ArCOOH + CF3COOH. (3)
13.5
10c,e NH4VO3 (IV), 43; 4.7 0.25
(III), 11
53
260
11
(IV), 52; (III), 25 3.2 0.2
27
28
21
28
1080
1480
950
A slight decrease in the yield of PhCOOH with pO
12f
13g
14h
(IV), 51
(IV), 100
(IV), 52
0.6 0.3
1.5 0.3
1.5 0.3
2
increased from 0.4 to 0.8 MPa (runs nos. 6 and 9) has
to do with the acceleration of the side oxidation
process leading to phenyl benzoate [7, 10] which
under the conditions of most experiments (see the
table) is formed in amounts of less than 30 mol %
with respect to PhCOOH.
1380
a
6
Reaction conditions: (9.5 0.5) 10 mol of Pd(OAc) , 4 ml
2
of PhH, 1 ml of CF COOH, 1 ml of (CF CO) O, 150 C, re-
action time 2 h. Determined by GLC. In brackets given is
3
3
2
b
found in some runs by the same method conversion of
From runs nos. 13 and 14 it follows that Pd can be
introduced to the reaction mixture as PdCl2 or
Pd(OH)2, but the process of formation of the catalytic
system in the first case is distinctly more lenghty than
in the second one.
c
d
5
benzene. 145 C. 1.1 10 mol of Pd(OAc) , 2 ml benzene,
2
e
5
f
6
130 C, 4 h. 9.2 10 mol of Pd(OAc) . 8.4 10 mol of
2
Pd(OAc) , 2 ml CF COOH, without (CF CO) O, 3.7 MPa N .
2
3
3
2
2
g
5
h
6
10 mol of PdCl .
9.2 10 mol of Pd(OH) .
2
2
For the oxidative carbonylation of toluene we used
the same catalytic systems containing [Rh(CO)2Cl]2,
the yield of the target product following the same
regularities as in the case of oxidative carbonylation
of benzene (see the table). However, in conformity
with the literature data [2, 7], the rhodium catalyst
gave higher proportion of para isomer in the target
product, and the reactions were carried out at a
somewhat lower temperatures (see Experimental).
followed, the process of formation of catalytically
active species may take different time and be dif-
ferently dependent on the reaction temperature and
partial pressures of the components of the gas mixture
for the compounds of different metals.
For the oxidative carbonylation of benzene at 130
150 C (runs nos. 6 and 7) Fe and V compounds can
be used simultaneously. It seems likely that these
metals catalyze reoxidation of Pd with molecular
oxygen independently of one another, since the sum
of yields of benzoic acid in runs nos. 3 and 4 is ca.
Carrying out the reaction of oxidative carbonyla-
tion of arenes in the presence of Cu [7], as well of Fe,
V, and Mo compounds, makes it possible to obtain
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 71 No. 9 2001

OXIDATIVE CARBONYLATION OF BENZENE AND TOLUENE CATALYZED
yields of ArCOOH tens times higher than that
1465
maximally possible in the absence of oxygen.
0.5
Mechanism of reaction (1) has been studied fully
enough for the case when Cu compounds were the
catalysts of reoxidation of the reduced forms of Rh
and Pd [7,11]. Fe, V, and Mo compounds evidently
play the same role as Cu compounds, but in the
course of the reaction the state of oxidation of the
metal cation changes from +3 to +2 (Fe), from +5 to
+4 (V), and from +6 to +5 (Mo).
0.4
0.3
0.2
0.1
2
1
To obtain an additional information on the me-
chanism of reaction (1), in the present study we
employed IR spectroscopy in situ with the use of a
reactor cuvette. The IR spectrum of the mixture of
Pd(O2CCF3)2, CF3COOH, (CF3CO)2O, and PhH
contains the band of trifluoroacetate anion at
0
20 40 60 80 100 120 140 160
Time, min
Plots of the optical density of the absorption bands at
1500 (1) and 1580 cm (2) of the IR spectra of the
reaction mixture containing 0.3 g Pd(O CCF ) , 0.3 ml
1
1
1580 cm , but shows no absorption bands in the
1
wave numbers interval 1490 1550 cm . After the
2
3 2
introduction into the reactor cuvette of carbon
monoxide at 0.2 MPa pressure and 30 C, in the IR
spectrum there appeared a new absorption band at
PhH, 7 ml CF COOH, and 1 ml (CF CO) O vs. time at
0.2 MPa CO and 30 C.
3
3
2
1
1500 cm , its optical density growing in the course
lower frequences. Thus, in the IR spectrum of the
complex ( 2-CH3CO)(Ph3P)2 Ru(CO)I the corres-
of the reaction and, passing through a maximum,
approaching zero (see the figure). Simultaneously,
the optical density of the absorption band at
1
ponding absorption bond appears at 1550 cm . So
the
intermediate
complex
(PhCO)PdO2CCF3
1
1
1580 cm also passed through a maximum, and in
presumably giving the absorption band at 1500 cm
should be assigned a 2-acyl structure.
the end of the experiment it reached the value several
times lower than the initial one. In this case the
observed maximum is probably connected with the
gradual dissolvation in the reaction mixture of poorly
soluble Pd(O2CCF3)2. Taking into consideration that
under the similar conditions Pd(O2CCF3)2 rapidly
reacts with benzene to give benzoic acid with the
yield of ca. 40% [2], we can propose that the absorp-
The employment of the reactor cuvette made it also
possible to observe the process of reduction of
Cu(O2CCF3)2 (I) in the oxidative carboxylation of
benzene in the presence of Pd(O2CCF3)2 (14 mol % of
compound I) at 80 C and 0.4 MPa CO in a
CF3COOH and (CF3CO)2O mixture. Under these
conditions, as the optical density of the trifluoro-
acetate group absorption band of compound I at
1
tion band at 1500 cm corresponds to an acyl
complex of palladium.
1
1695 cm rapidly decreases, there appear and grow
1
It is known that in the IR spectra of benzoylpalla-
dium halide and its derivatives stabilized by phos-
phine ligands the absorption band of the acyl group is
bands at 2145 and 1670 cm corresponding to the
absorption of the coordinated CO and trifluoroacetate
group in (CO)CuO2CCF3, respectively [14]. Thus,
with the use of the IR spectroscopy in situ it becomes
possible to determine the state of oxidation of the Cu
cation in the course of reaction (1), kinetic experi-
ments including.
1
found at about 1650 cm [12] which is charactristic
of 1-acyl complexes [13]. Should the structure of
1-acyl complex retained in the absence of phosphine
ligands and the halide anion changed by the anion of
trifluoroacetetate, then because of increased positive
charge on the carbon atom of the acyl group and the
resulting increased multiplicity of its carbon to
oxygen bond, this absorption bond would appear at
higher frequences.
EXPERIMENTAL
The IR spectra of the reaction mixtures were taken
on an UR-20 instrument in the region of 2200
1
1400 cm with the use of a reactor cuvette made of
In 2-acyl complexes [13] additional coordination
between the atom of oxygen of the acyl group and the
cation of metal results in decreased multiplicity of the
carbon to oxygen bond in the acyl group and in the
shift of the corresponding absorption band towards
stainless steel and equipped with a plunger stirring
system activated by means of a surge injector, CaF2
windows, and a manometer. The design of the reactor
cuvette permitted the thickness of the optical layer to
be varied over a wide range.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 71 No. 9 2001

1466
KALINOVSKII et al.
The reactions of oxidative carbonylation, analyses
Dokl. Akad. Nauk SSSR, 1960, vol. 130, no. 4,
pp. 820 823.
of the reaction mixtures, and determination of the
isomeric composition of the target product by GLC
were carried out by the procedure described in [7].
6. US Patent no. 4431839, 1984; Ref. Zh. Khim., 1984,
22 N 150 P.
7. Kalinovskii, I.O., Leshcheva, A.A., Kuteiniko-
va, M.M., and Cel’bshtein, A.I., Zh. Obshch. Khim.,
1990, vol. 60, no. 1, pp. 123 130.
Pd carboxylates [15,16], [Rh(CO)2Cl]2 [17], and
Cu(II) trifluoroacetate [18] were prepared by known
procedures. PdCl2, Cu(II) acetate, Fe(II) oxalate,
ammonium vanadate and paramolybdate, and V2O5
were of pure grade. Benzene, toluene, and
(CF3CO)2O of pure grade were used after distilla-
tion. CF3COOH of pure grade was distilled over
sulfuric acid.
8. Zhizhinas, E.G., Matveev, K.I., and Kuznetsova, L.I.,
Kinet. Katal., 1985, vol. 26, no. 2, pp. 461 465.
9. Arzoumanidis, G.G. and Rauch, F.C., J. Mol. Catal.,
1980, vol. 9, no. 3, pp. 335 338.
10. Kalinovskii, I.O., Leshcheva, A.A., Pogorelov, V.V.,
and Gel’bshtein, A.I., Khim. Tverd. Topl., 1993, no. 2,
pp. 8 10.
Oxidative carbonylation of toluene. A reaction
mixture containing 4 ml of toluene, 1 ml of
CF3COOH, 1 ml of (CF3CO)2O, 0.0020 g of
[Rh(CO)2Cl]2, and 0.0605 g NH4VO3, at initial partial
pressures (set at 20 C) of oxygen 0.3 MPa and
carbon monoxide 1.2 MPa was kept for 4 h at 125 C.
In this reaction we obtained 1.33 g (26%, 970 mol per
g-atom of Rh) of a mixture of toluic acids. Isomeric
composition of the target product: 76.5 of p-, 21 of m-,
and 2.5% of r-toluic acid.
11. Leshcheva, A.A., Kalinovskii, I.O., Pogorelov, V.V.,
Noskov, Yu.G., and Gel’bshtein, A.I., Kinet. Katal.,
1998, vol. 39, no. 3, pp. 389 398.
12. Carrou, P.E. and Heck, R.F., J. Am. Chem. Soc., 1976,
vol. 98, no. 14, pp. 4115 4127.
13. Collman, J.P., Hegedus, L.S., Norton, J.R., and Fin-
ke, R.G., Principles and Applications of Organotran-
sition Metal Chemistry, Mill Valley, CA: University
Science Books, 1987. Translated under the title
Metalloorganicheskaya khimiya perekhodnykh metal-
lov, Moscow: Mir, 1989, vol. 1, pp. 108 113.
REFERENCES
1. US Patent no. 3920734, 1975; Ref. Zh. Khim., 1977,
14. Scott, A.F., Wilkening, L.L., and Rubin, B., Inorg.
Chem., 1969, vol. 8, no. 11, pp. 2533 2534.
5 N 173 P.
2. Kalinovskii, I.O., Pogorelov, V.V., Gel’bshtein, A.I.,
and Akhmedov, N.G., Zh. Obshch. Khim., 2001,
vol. 71, no. 9, pp. 1539 1544.
15. Stephenson, T.A., Morehouse, S.M., Powell, A.R.,
Heffer, J.P., and Wilkinson, G., J. Chem. Soc., 1965,
no. 6, pp. 3632 3640.
3. Fujiwara, Y., Kawanchi, T., and Taniguchi, H., Chem.
Commun., 1980, no. 5, p. 220.
16. Henry, P.M., Palladium-catalysed organic reactions,
Adv. Organometal. Chem., 1975, vol. 13, pp. 363
452.
4. Masters, C., Homogeneous Transition-metal Catalysis,
London: Chapman and Hall, 1981. Translated under
the title Gomogennyi kataliz perekhodnymi metallami,
Moscow: Mir, 1983, p. 300.
17. Inorganic synthesis, New York: McGraw-Hill, 1966,
vol. 8, pp. 211 213.
18. Patel, K.S. and Fanisan, J.A., J. Inorg. Nucl. Chem.,
5. Moiseev, I.I., Vargaftik, M.N., and Syrkin, Ya.K.,
1976, vol. 38, no. 5, pp. 1001 1005.
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