ISSN 1070-3632, Russian Journal of General Chemistry, 2008, Vol. 78, No. 2, p. 323.
Pleiades Publishing, Ltd., 2008.
Original Russian Text
A.I. Rakhimov, R.V. Fisechko, 2008, published in Zhurnal Obshchei Khimii, 2008, Vol. 78, No. 2, p. 338.
LETTERS
TO THE EDITOR
New Synthesis of Polyfluoroalkyl Cyclohexyl Ethers
A. I. Rakhimov and R. V. Fisechko
Volgograd State Technical University,
pr. V.I. Lenina 28, Volgograd, 400131 Russia
e-mail: organic@vstu.ru
Received June 26, 2007
DOI: 10.1134/S1070363208020266
1
Polyfluorinated cyclohexyl ethers were previously
prepared by hydrogenation of mixtures of polyflu-
orinated alcohols and ketones under pressure over a
palladium catalyst [1].
1.75 m and 1.31 m (ring CH2). The H NMR spectra
were taken on a Varian Mercury Plus spectrometer
(300 MHz) in CDCl3 against internal TMS.
(1,1,3-Trihydroperfluoropropoxy)cyclohexane
(I). A solution of 2.3 g of cyclohexanol and 0.015 ml
of DMF in 10 ml of chloroform was cooled to 10 C,
and a solution of 4.93 g of 1,1,3-trihydroperfluoro-
propyl chlorosulfite in 10 ml of chloroform was added
with stirring at this temperature. The reaction mixture
was then heated to 25 C and kept for 3 h. The liberat-
ing hydrogen chloride and sulfur dioxide were re-
moved with stream of dry air. The solvent was eva-
porated, and the residue was distilled in a vacuum to
give 4.03 g (82%) of the target ether, bp 95 C (3 mm
Hg), n2D0 1.3798, d240 1.1005. Found F, %: 32.20,
calculated F, %: 35.48.
We found that, unlike secondary aliphatic alcohols
which do not react with polyfluoroalkyl chlorosulfites,
cyclohexanol reacts with these compounds under
DMF catalysis to form cyclohexyl ethers in 65 82%
yields depending on the size of the perfluorocarbon
chain in the alkyl chlorosulfite.
OH + H(CF2)nCH2OS(O)Cl
DMF
OCH2(CF2)nH
SO2, HCl
I, II, III
(1,1,5-Trihydroperfluoropentoxy)cyclohexane
(II) was prepared in a similar way from 2.5 g of
cyclohexanol, 7.9 g of 1,1,5-trihydroperfluoropentyl
chlorosulfite, and 0.0016 ml of DMF. Yield 5.9 g
(75%), bp 105 C (3 mm Hg), n2D0 1.3865, d420 1.3733.
Found F, %: 49.61; calculated F, %: 48.37.
n = 2 (I); n = 4 (II); n = 6 (III).
The yield of the target product decreases in
the order n = 2 > n = 4 > n = 6. The resulting ethers
are transparent liquids readily distillable in a vacuum
and possessing a specific odor.
(1,1,7-Trihydroperfluoroheptyloxy)cyclohexane
(III) was prepared in a similar way from 2.6 g of
cyclohexanol, 10.77 g of 1,1,7-trihydroperfluoroheptyl
chlorosulfite, and 0.0016 ml of DMF. Yield 7.0 g
(65%), bp 123 C (3 mm Hg), n2D0 1.3891, d420 1.4067.
Found F, %: 54.12; calculated F, %: 55.04.
The structure of the synthesized polufluoroalkyl
cyclohexyl ethers was established by means of IR and
1H NMR spectroscopy. IR spectrum, , cm :
1
1170 m [ (C O C)], 1170 s [ (CF2)], 2878 m,
2965 m [ (CH2)], 3005 w (CHF2). The IR spectra
were recorded on a Specord M-82 spectrometer in thin
REFERENCES
1
layer on KBr plates. H NMR spectrum, , ppm: 5.99
t.t (HCF2), 3.95 t (CH2CF2), 2.89 m (ring CH),
1. US Patent 6060626, Chem. Abstr., 2002, no. 09/05744.
323
Rakhimov
