Synthesis of Butyl Rubber by Cationic Polymerization
in Methyl Chloride in the Presence of Alkyl Chlorides
O. V. Sofronova, E. A. Markina, S. M. Chelnokova, and A. G. Sakhabutdinov
Scientific and Technological Center, Nizhnekamskneftekhim Public Joint-Stock Company,
Nizhnekamsk, Tatarstan, Russia
Received October 1, 2010
Abstract—The copolymerization of isobutylene with isoprene in methyl chloride in the presence of a catalytic
system based on aluminum chloride and modified with alkyl chlorides was studied systematically.
AND POLYMERIC MATERIALS
ISSN 1070-4272, Russian Journal of Applied Chemistry, 2011, Vol. 84, No. 8, pp. 1430–1433. © Pleiades Publishing, Ltd., 2011.
Original Russian Text © O.V. Sofronova, E.A. Markina, S.M. Chelnokova, A.G. Sakhabutdinov, 2011, published in Zhurnal Prikladnoi Khimii, 2011,
Vol. 84, No. 8, pp. 1368–1372.
Butyl rubber and halobutyl rubber are widely used
owing to unique properties such as heat resistance,
chemical stability, and unique impermeability to gases.
Butyl rubber vulcanizates exhibit excellent amortize-
tion properties. The major application field of butyl
rubber is production of inner tubes for tires and of
diaphragms for shaper vulcanizers, and that of halo-
butyl rubber is fabrication of the sealing layer for
Initially the designed capacity of the Nizhne-
kamskneftekhim Public Joint-Stock Company for butyl
rubber production was 30 000 t annually. Today the
output is 120 000 t of rubber annually. Intense growth
of the consumption of butyl rubbers and halobutyl
rubbers requires further growth of the production
capacity. The task of today is to increase the rubber
output to 150 000 t annually.
The possibilities of ensuring production growth by
more intense use of the equipment have already been
exhausted, and, therefore, to increase the output of
butyl rubber it is necessary to improve the production
The butyl rubber output can be increased by
increasing the initial concentration of isobutylene in
the charge, by enhancing the stability of butyl rubber
suspension in methyl chloride, and by reducing the
rubber loss caused by its adhesion to the equipment.
A distinctive feature of the copolymerization of
isobutylene with isoprene, performed by the cationic
mechanism, is very high polymerization rate with
considerable heat evolution. As a rule, the heat
removal from the reaction zone is extremely difficult.
A necessary condition for suspension production of
butyl rubber is low polymerization temperature. The
glass transition point of butyl rubber is as low as –69°
C, and with an increase in the reaction mixture
temperature the polymer passes from the glassy state to
the hyperelastic state, which leads to its adhesion to
parts of the polymerization reactor.
An increase in the initial concentration of iso-
butylene causes an increase in the heat evolution and a
decrease in the stability of the butyl rubber suspension.
Furthermore, the rubber quality decreases, because the
polymer becomes more heterogeneous with respect to
Therefore, the development of methods for
controlling the activity of the catalytic system based on
aluminum chloride in the synthesis of butyl rubber and
assurance of the stability of the butyl rubber sus-
pension, especially at increased concentration of the
monomers, with the aim to increase the polymer
output, are topical problems .
It is known that alkyl chlorides can be used as
cationogens in the catalyst activation process [2–4].
In this study we determined the main relationships
of the synthesis of butyl rubber in the presence of a
catalytic system based on aluminum chloride modified
with alkyl chlorides.