Russian Journal of Applied Chemistry, 2010, Vol. 83, No. 7, pp. 1328−1332.
Pleiades Publishing, Ltd., 2010.
Original Russian Text
Zh.A. Otvalko, M.V. Drugov, A.I. Tverdov, S.V. Kuz’min, E.V. Trifonova, 2010, published in Zhurnal Prikladnoi Khimii, 2010, Vol. 83,
No. 7, pp. 1220−1224.
AND POLYMERIC MATERIALS
Introduction of Chlorine into Polydienes
with a High Content of Vinyl Units
Zh. A. Otvalko, M. V. Drugov, A. I. Tverdov, S. V. Kuz’min,
and E. V. Trifonova
Research Institute of Synthetic Rubber, Federal State Unitary Enterprise, St. Petersburg, Russia
Received March 3, 2010
Abstract—Chlorination of polydienes with a high content of vinyl units without using gaseous chlorine or HCl
was studied. The following methods were tested: chlorination, hydrochlorination, addition of dichlorocarbenes
to double bonds in two-phase systems using phase-transfer catalysts, and addition of dichlorocarbenes under
homogeneous conditions in the presence of a catalytic system.
Chlorination of polydienes is usually performed by
the reaction of gaseous chlorine or hydrogen chloride
with polydiene in an organic solvent [1–10]. Chlorine can
also be introduced into polydienes by their modiﬁ cation
with chlorinated organic compounds, e.g., by the
reaction of a halogenated organosiloxane compound
with active conjugated diene polymer containing an
alkali metal at the chain terminus , by addition of
dichlorocarbenes to double bonds in a two-phase system
using phase-transfer catalysts [12–14], etc.
Procedures have been developed for chlorination of
polydienes with a high content of vinyl units, prepared
using an environmentally clean catalytic system
based on soluble sodium (potassium) and magnesium
compounds [15, 16]. The structure of molecular chains
of such polydienes ensures their unique damping,
adhesion, and cohesion properties [17–22]. Chlorination
was performed in a homogeneous medium and in two-
phase systems using phase-transfer catalysts.
(A) Introduction of chlorine into polydienes
under the conditions of phase-transfer catalysis in
an organic solvent in the presence of an oxidant.
Chlorination of polydienes under the conditions of
phase-transfer catalysis allows the use of gaseous
chlorine to be abandoned, because chlorine is generated
in situ by the reaction of hydrogen chloride with
hydrogen peroxide in the aqueous phase.
Chlorination of alkenes with a high yield of dichloro
derivatives (up to 77%) is performed by treatment of
a solution of an alkene in carbon tetrachloride with
concentrated hydrochloric acid and 30% hydrogen
peroxide in the presence of triethylbenzylammonium
chloride (TEBAC) under cooling with ice . The
overall reaction is as follows:
RСН=СНR' + 2HCl + H
→ RCHCl – CHClR'.
In chlorination of polydienes with gaseous chlorine,
the addition is always accompanied by side reactions
such as substitution with the release of HCl. In addition,
cyclization and cross-linking take place. The reaction
direction depends on the process conditions. The
reaction either is ionic or occurs via the step of an active
transition complex (Scheme 1).
Experiments on chlorination of polydienes with
high content of vinyl units were performed taking
into account the procedure of alkene chlorination and
structural features of the polymers. In oxidation of HCl,
it is not quite clear whether a Cl
molecule is formed
or chlorine acts in the atomic state. These factors will
determine the direction of the main elementary steps
of the process. A study of microstructural features of
chlorinated polydienes can give insight into the nature
of the occurring processes. Data on molecular-weight