Russian Journal of Applied Chemistry, 2011, Vol. 84, No. 1, pp. 133−137.
Pleiades Publishing, Ltd., 2011.
Original Russian Text © Yu.B. Monakov, Yu.V. Morozov, I.Sh. Nasyrov, V.Z. Mingaleev, V.P. Zakharov, E.A. Glukhov, 2011, published in Zhurnal Prikladnoi
Khimii, 2011, Vol. 84, No. 1, pp. 133−137.
AND POLYMERIC MATERIALS
Modiﬁ cation of Titanium Catalytic Systems
for 1,4-cis-Polyisoprene Synthesis
Yu. B. Monakov, Yu. V. Morozov, I. Sh. Nasyrov, V. Z. Mingaleev,
V. P. Zakharov, and E. A. Glukhov
Institute of Organic Chemistry, Ufa Scientiﬁ c Center, Russian Academy of Sciences, Ufa, Bashkortostan, Russia
Sintez-Kauchuk Public Joint-Stock Company, Sterlitamak, Bashkortostan, Russia
Bashkir State University, Ufa, Bashkortostan, Russia
Received March 24, 2010
Abstract—The kinetics of isoprene polymerization in an aliphatic solvent on a titanium catalyst modiﬁ ed with
n- and π-electron-donor additives, with preliminary single circulation of the reaction mixture through a tubular
turbulent apparatus, was studied.
Microheterogeneous titanium catalytic systems
are used in commercial production of SKI-3 isoprene
rubber . In isoprene polymerization, these catalytic
systems exhibit high activity and stereospeciﬁ city
(up to 98% 1,4-cis units), ensuring preparation of
rubber with the set of required consumer’s properties.
Because of microheterogeneity of the titanium catalyst,
it is possible to affect the polymerization course and
molecular characteristics of the products by varying the
size distribution of catalytically active particles [1–3].
Correspondingly, a procedure for modiﬁ cation of the
catalytic system by adding dienes favoring dispersion of
the catalyst particles and enhancing the catalyst activity
found wide use [1, 4]. The surface structure of the catalyst
can also be affected by varying the hydrodynamic
conditions in the reaction zone, mainly in the initial
moment of the polymerization when the polymer
content in the reaction mixture is low. In particular, it
was found  that the hydrodynamic action in turbulent
ﬂ ows on the reaction mixture in isoprene or butadiene
polymerization leads to an increase in the concentration
of active sites (ASs) and to their redistribution with
respect to the chain termination probability. In this case,
an important factor is catalyst particle disintegration
under the action of the kinetic energy of the turbulent
In this study we examined the polymerization
relationships with hydrodynamic action on titanium
catalytic systems of polyisoprene synthesis under the
conditions close to those of industrial synthesis of SKI-
3 isoprene rubber.
The catalytic complex was prepared and the
polymerization was performed in a nitrogen atmosphere
under the conditions ensuring efﬁ cient protection of
the reaction mixture from moisture and impurities.
The catalytic complex was prepared by combining
at –10 to –15°С a toluene solution containing TiCl
and diphenyl oxide (DPO) with a toluene solution
and piperylene. The molar
ratio of the corresponding component of the catalytic
complex and of n- and π-electron-donor additives (DPO
and piperylene, respectively) was 1 : 0.15. Addition of
DPO and piperylene increases the rate constant of the
polymer chain propagation and the AS concentration,
Isoprene polymerization was performed in
isopentane at 25°С under the following conditions:
catalyst concentration с
= 1.30 mM, molar ratio Al/Ti =
1, monomer concentration 1.56 M. The polymerization
was performed by two methods, with the other conditions