Russian Journal of Applied Chemistry, 2009, Vol. 82, No. 11, pp. 2068−2070.
Pleiades Publishing, Ltd., 2009.
Original Russian Text
A.V. Kalinin, G.A. Nikolaev, L.V. Agibalova, 2009, published in Zhurnal Prikladnoi Khimii, 2009, Vol. 82, No. 11, pp. 1919−1921.
Condensation Synthesis of High Molecular
A. V. Kalinin, G. A. Nikolaev, and L. V. Agibalova
“Lebedev Synthetic Rubber Research Institute,” Federal State Unitary Enterprise, St. Petersburg, Russia
Received 15 April, 2009
Abstract—Synthesis approach to high molecular organosilicon polymers by condensation way merely starting
from low molecular α,ω-dihydroxyoligomers was developed.
Polymerization reaction with ring opening is well
known to be the main synthesis method of high molecular
polysiloxanes. However, it is impossible to obtain
pure polymer containing absolutely no cyclosiloxanes
admixtures by this way since the polymerization reaction
bears equilibrium nature :
Cyclosiloxanes 'Polymers (1)
In the case of cyclotrisiloxane polymerization, whose
molecules represent strain cyclic system, the equilibrium
is shifted to the right more than in the case of cycles
involving more than three siloxane fragments of the
similar structure. Here, polymer yields can be high .
Nevertheless, the reaction mass always contains some
number of siloxane fragments with such number of
silicone units as n=4–6 [3, 4], and of microcycles 
forming in side reactions, for example, dimerization
of cycles and break up of siloxane bond in polymer by
The challenge of this work is to ﬁ nd approach, which
allows reliable obtaining the high molecular polysiloxanes
being free of cyclic compounds.
Formation of Si–O–C bonds on the reaction of
organosilicon derivatives of carboxylic acid amides
[6–9] and sulfonic acids  with hydroxyl group at
the carbon atoms of organic compounds, in particular,
of phenols  and saccharides  have been described
in scientiﬁ c literature. One may suppose that analogous
process should be occur, when similar compounds react
with hydroxyl group on the silicon atom to form Si–O–Si
It was established that the heating of low molecular
α,ω-hydroxypolydimethylsiloxane with bis-(diethylamin
o)dimethylsilane in the presence of N-methylformamide
leads to almost tenfold increase in molecular mass of
polymer. An effort to carry out this reaction in the absence
of N-methylformamide causes no substantial increase
in molecular mass. It can be assumed that at ﬁ rst in situ
formation of silyl derivatives of N-methylformamide
occurs according to Scheme 1.
Owing to diethyl amine has the substantially lower boiling
point than N-methylformamide, equilibrium is shifted to
right. Then diethylaminomethylformamidodimethylsilane