ISSN 1070-4272, Russian Journal of Applied Chemistry, 2007, Vol. 80, No. 7, pp. 1090 !1096. + Pleiades Publishing, Ltd., 2007.
Original Russian Text + V.P. Boyarskii, T.E. Zhesko, S.A. Lanina, G.F. Tereshchenko, 2007, published in Zhurnal Prikladnoi Khimii, 2007, Vol. 80,
No. 7, pp. 1120 !1126.
OF CHEMISTRY AND TECHNOLOGY
Dechlorination of Persistent Organic Pollutants
Polychlorobiphenyls by Catalytic Carbonylation
V. P. Boyarskii, T. E. Zhesko, S. A. Lanina, and G. F. Tereshchenko
VNIIneftekhim Open Joint-Stock Company, St. Petersburg, Russia
Galar Scientific and Production Firm, Limited Liability Company, St. Petersburg, Russia
St. Petersburg Scientific Center, Russian Academy of Sciences, St. Petersburg, Russia
Received April 19, 2007
Abstract-A new approach to dechlorination of [dioxin-like] ecotoxicants, polychlorinated biphenyls, based
on carbonylation, was suggested. The weakly reactive aryl halides are activated by effective catalytic systems
based on epoxide-modified cobalt carbonyl in alcoholic alkali solutions.
Polychlorinated biphenyls (PCBs) have a set of
unique physicochemical properties and are widely
used as dielectrics in transformers and capacitors, as
hydraulic fluids, and as heat carriers. At the same
time, PCBs are highly toxic; they damage the im-
mune, endocrine, and nervous systems and exhibit
carcinogenic properties [1, 2]. Because of the high
vapor pressure and noticeable volatility, they are
capable of transboundary transport to long distances.
Being lipophilic, these compounds accumulate in
adipose tissues of animals and humans and get in-
volved in food chains. Polychlorobiphenyls are ex-
tremely resistant to biological and chemical degrada-
tion and can exist in the environment for centuries.
Therefore, along with superecotoxicants, dioxins
(polychlorodibenzodioxins) and polychlorodibenzo-
furans, they are included in the main list of persistent
organic pollutants (POPs). According to Stockholm
convention on POPs, which came into force in 2004,
these compounds are to be destroyed or utilized .
Today the production of PCBs has been stopped.
However, by the beginning of the 1990s, more than
1.5 mln tons of technical PCB mixtures (including
approximately 180 thousand tons in the former Soviet
Union) have been produced in the world. In Russia,
up to 35000 t of PCBs are still in use, including more
than 1000 t in St. Petersburg and Leningrad oblast
(according to incomplete data) .
Much attention is given today to the development
of procedures for rendering polychlorobiphenyls
harmless. It is known that spent technical oils that are
not subjected to regeneration are commonly incine-
rated, but this procedure is unacceptable for PCB-
containing oils, because of formation of dioxins in the
process. The most promising way to decrease the
amount of PCBs in the environment is their chemical
reprocessing into environmentally safe products.
Much attention is given to the development of meth-
ods for PCB reduction with alkali metals and alkali
metal hydrides [2, 3], and also of safer and more
feasible methods of catalytic reductive dehalogenation
[2, 4]. It is also suggested to treat PCBs with alkali
metal polyglycolates with the formation of ethers .
In this study we examined the principal possibility
of reprocessing technical PCB mixtures by carbonyla-
tion, with the aim to subsequently develop a process
for PCB utilization and conversion into useful prod-
ucts (acids and their derivatives: salts, esters, amides).
These products can find wide use in production of
dyes and pigments, polymers and resins, lubricants,
surfactants, corrosion inhibitors, and additives to oils
The suggested procedure is based on the previously
developed  principally new catalytic systems
based on modified cobalt carbonyl, capable of activat-
ing aromatic halides and involving them in carbonyla-
tion with the formation of carboxylic acids and their
derivatives. For the carbonylation of PCBs, which are
inert aryl chlorides, we chose the most active catalytic
systems promoted with propylene oxide (PO). The
advantages of this procedure are the use of cheap and
available raw materials and low power consumption