Russian Journal of Applied Chemistry, 2013, Vol. 86, No. 2, pp. 253−257.
Pleiades Publishing, Ltd., 2013.
Original Russian Text © N.V. Lebedev, O.V. Barinov, V.V. Berenblit, V.S. Plashkin, V.A. Gubanov, 2013, published in Zhurnal Prikladnoi Khimii, 2013,
Vol. 86, No. 2, pp. 273−277.
AND POLYMERIC MATERIALS
Isomerisation of Perﬂ uoro(alkenyl vinyl ether)
with Terminal Double Bond
N. V. Lebedev, O. V. Barinov, V. V. Berenblit,
V. S. Plashkin, and V. A. Gubanov
Federal State Unitary Enterprise “Scientiﬁ c Research Institute of Synthetic Rubber,” St. Petersburg, Russia
Received November 6, 2012
Abstract—Isomerization of perﬂ uoro(5-vinyloxy)pent-1-ene by potassium and cesium ﬂ uoride action was exam-
ined. Products of isomerization, a mixture of cis-and trans-isomers of vinyl ether with an internal double bond,
and cyclic structures were identiﬁ ed by
F NMR spectroscopy.
Perﬂ uoro vinyl ethers are used as components of
ﬂ uoro-copolymer applied in modern technology as
a heat and aggressive resistant elastomeric materials .
As a rule, perﬂ uoro vinyl ethers are produced
by pyrolytic decarboxylation of sodium salts of
perﬂ uoroalkoxycarboxylic acids . A similar
method underlies obtaining perﬂ uorinated oleﬁ ns and
dioleﬁ ns with a terminal double bond . Pyrolysis of
potassium salts also leads to high yields of oleﬁ ns, but is
accompanied by isomerization of the double bond with
formation of a mixture of isomers [4, 5].
As shown in  along with terminal oleﬁ ns
isomeric unsaturated compounds, mainly polyﬂ uoro-
2-alkenes, are formed in pyrolysis of sodium salts of
polyﬂ uorocarboxylic acids at temperatures 250–300°C
in the absence of solvent. It was found that carbon-like
residue of sodium ﬂ uoride from a salt decomposition is
characterized by catalytic activity.
Double bond migration in perﬂ uorooleﬁ nes under
the inﬂ uence of ﬂ uoride ion has long been known and
is used for isomerisation of perﬂ uoro-terminal alkenes
Obviously, the activity of formed ﬂ uoride-anion
bound to the metal cation is the main factor contoling
the yield and structure of isomeric products of
pyrolytic decarboxylation or directly isomerization of
perﬂ uorooleﬁ n.
The study is an attempt of performing isomerization
of the terminal double bond of perﬂ uorinated oleﬁ n
containing oxyvinyl group to internal bond in the
presence of alkali metal ﬂ uorides of different activity.
Perﬂ uoro(5-vinyloxy)pent-1-ene (I) promising
in application to ﬂ uorocopolymers was selected as
an object of investigation.
Isomerization of terminal double bond of I under
the action of alkali metal ﬂ uorides at the boiling point
of the substrate I is accompanied by the formation of
trans-isomers of perﬂ uoro(5-vinyloxy)pent-2-ene (II
cis-perﬂ uoro(5-vinyloxy)pent-2-ene (II
), and products
of their cyclization (III
) (see the scheme).
It was found that the use of cesium ﬂ uoride at the
boiling point of starting material led to the formation of
isomers II with an admixture of the cyclic products III
(in total ~6.3% according to GLC) with almost complete
conversion of starting material I for 2 h (Fig. 1). Adding
a small amount of diglyme to cesium ﬂ uoride in the
reaction mixture led to a complete conversion of isomers
II in the cyclic products III (Fig. 3).
The use of potassium ﬂ uoride as a catalyst at the
boiling point of starting material has not resulted in the
expected isomerization of the double bond. Adding to the
reaction mixture a small amount of diglyme gave slow
formation of isomers II and almost no cyclic products
III (in total about 1% by GLC) therewith the conversion