1070-4272/05/7811-1844C2005 Pleiades Publishing, Inc.
Russian Journal of Applied Chemistry, Vol. 78, No. 11, 2005, pp. 1844!1848. Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 11,
2005, pp. 1875!1880.
Original Russian Text Copyright + 2005 by Boyarskii, Zhesko, Lanina.
AND CORROSION PROTECTION OF METALS
Synthesis of Aromatic Carboxylic Acids by Carbonylation
of Aryl Halides in the Presence of Epoxide-Modified Cobalt
Carbonyls as Catalysts
V. P. Boyarskii, T. E. Zhesko, and S. A. Lanina
VNIINeftekhim Joint-Stock Company, St. Petersburg, Russia
Galar Research and Production Limited Liability Company, St. Petersburg, Russia
Received July 19, 2005
Abstract-A new procedure was developed for synthesis of aromatic and heteroaromatic acids and their deri-
vatives (esters, salts) by carbonylation of the corresponding aryl halides. The acids are selectively formed in
a high yield under very mild conditions. Highly active catalytic systems, base-containing alcoholic solutions
of cobalt carbonyl modified with epoxides, were used to activate aryl halides.
Aromatic acids and their derivatives (esters and
salts) are widely used both in preparative organic
chemistry and as commercial raw materials to produce
pharmaceuticals, plant protecting agents, paint and
varnish materials, lubricants, and corrosion inhibitors.
In addition, aromatic carboxylic acids are used as the
base of modern liquid-crystal materials. Di- and poly-
aryl carboxylic acids are used in production of poly-
ester fibers and liquid-crystal thermoplastics as well
as electroluminophores in development of new equip-
The conventional methods for preparing aromatic
acids under industrial and laboratory conditions are
different and involve classical organic reactions:
alkylation, acylation, oxidation, and cyanidation. The
disadvantages of these methods are their low selectiv-
ity and high consumption of raw materials. The syn-
thesis is multistep and requires complex process
schemes. Many of these methods are environmentally
Recently, researchers turned attention to an alterna-
tive one-step selective procedure for preparing aromat-
ic carboxylic acids: carbonylation of the correspond-
ing aryl halides. Aryl halides are readily available and
cheap. However, these compounds, especially the
cheapest aryl chlorides, have low reactivity.
Originally, [soft] aryl halides (iodides and brom-
ides) were used for this purpose. These compounds
can be activated by oxidative addition to complexes
of palladium in a low oxidation state .
At the same time, alkylaromatic halides are car-
bonylated under extremely mild conditions in alcohols
in the presence of a base and conventional catalyst of
oxosynthesis, octacarbonyldicobalt [1, 4, 5].
Alkylcobalt carbonyl complexes are formed in situ
by the reaction of alkyl halides reactive in nucleophil-
ic substitution (e.g., methyl chloroacetate) with di-
cobalt octacarbonyl in alcoholic solutions containing a
base. These complexes can activate weakly active aryl
halides, involving them in carnolylation . In this
case, alkyl halides are cocatalysts (activators) of
cobalt carbonyl in carbonylation of aryl halides:
ArHal + CO %%%%%%$ ArCOOR,
ROH + B
where A and B are cocatalyst and base, respectively.
The facts that acceptor substituents accelerate car-
bonylation of substituted bromobenzenes and one-
electron acceptors (nitrobenzene and anthraquinone)
inhibit carbonylation of aryl halides suggests radical
anion mechanism of aryl halide activation (S
The actual carbonylation catalyst is, apparently, the
anionic complex [RCo(CO)
the nucleophilic attack of the carbon atom of one of
the carbonyl groups by the methylate anion. The
nucleophilic power of this complex is high. Since
benzyl chloride is also carbonylated under these con-
ditions, its was gradually fed by a special procedure to
the reaction mixture to maintain the catalyst in the ac-
tive form and to increase the conversion (see figure).
A series of valuable aromatic acids were prepared by
carbonylation of the corresponding aryl halides in