1250
FENICHEV et al.
isomerism associated with an axial or equatorial position
of the keto group relative to perfluorocyclohexyl rings
as well as with conformation of the latter in the form of
chair or bath.
electrochemical fluorination of benzoyl chloride, sepa-
rating it from electrolysis products by distillation with
93.5 wt% content.
Anhydrous sodium fluoride (GOST 4463-76, cesium
fluoride (TU 6-09-04-254-85), calcium fluoride (TU
95-23-17-91), and potassium fluoride dihydrate (GOST
20848-75), which was dehydrated in a vacuum oven at
200°C, were used for obtaining catalysts. Catalysts on
activated carbon BAU-A-2 was prepared by impregnating
it by aqueous solutions of the corresponding fluorides in
term of 15–20 wt %, followed by drying in an oven at
130–150°C for 3–5 hours
Research of perfluorodialkyl ketones showed that
like hexafluoroacetone they form hydrates in interaction
with water. In particular, perfluoro-3-methylbutan-2-diol
[hydrate (VII)] and perfluoro-3-methylpentane-2-diol
[hydrate (III)] were identified by 19F NMR spectra.
EXPERIMENTAL
For the analysis of the products of the reaction of
perfluoroacyl fluorides with perfluoroolefins a Crystal
2000M chromatograph is typically used with thermal
conductivity detector at 125°C on a column of diameter
3 mm and length of 2 m filled with 20% α,α,α-tris-(β-
cyanoethyl)acetophenone on silochrome C-80 at 80°C
(standard phase), carrier gas helium (flow 30 cm3 min–1).
Perfluoropolyether PEF-5 (20%) on silochrome C-3 was
used as a stationary phase for analysis of stereoisomers.
The catalyst was loaded into a metal-autoclave reac-
tor of 100 cm3 volume, made of steel 12Cr18Ni10Ti
equipped with a pressure gauge, thermocouple, and
a needle valve.
Immediately before the synthesis in the study of the
catalytic activity the catalysts were finally dried in the
reactor in a stream of dry nitrogen at 200°C for 12 hours
with periodic evacuation at 2–5 mm Hg for 10 min. Then
the reactor was cooled to –40°C and HFPO and HFPwere
sequentially condensed in it by 0.1 mol. The mixture in
the reactor was heated to 65–180°C and maintained for
6–8 hours with checking the pressure, which did not ex-
ceed 1.1 MPa.Afterwards the reactor was cooled to room
temperature, and the reaction products were fractionated
and analyzed by GLC.
The resulting products mixture was separated into the
laboratory glass column of 12 mm in diameter, 0.5 m
height packed with 4 mm diameter coils with monitoring
the composition of the probed fractions by GLC.
The products were identified by 19F NMR spectra
recorded at the frequency 470.6 MHz in a spectrometer
Bruker Spectrospin HA-500 in the standard ampoules
(5 mm) in 20% solution of deuterochloroform with hexa-
fluorobenzene as internal standard.
When studying the interaction of various perfluo-
roacyl fluorides with fluoromonomers, reagents were
charged into the reactor successively by 0.1 mol per 30
g of catalyst: cesium fluoride (0.03 mol) in an amount of
20 wt% applied to activated carbon BAU-A-2, and then
the synthesis was carried out as described above.
Monomers containing not less than 99.9 vol % of
tetrafluoroethylene (according to STP 044-39-2001) and
hexafluoropropylene (TU 95-417-77), and also hexafluo-
ropropylene epoxide (about 99.5%, TU 95-793-80) were
used as initial perfluorinated products
CONCLUSIONS
Perfluoroacyl fluorides were prepared:
(a) pentafluoropropionyl fluoride (II): by passing
HFPO through a tubular reactor heated to 110–120°C,
filled with activated carbon BAU-A-2 (State standard
GOST 6217-74) with 20 wt% cesium fluoride at a pres-
sure of 0–0.25 MPa;
(1) A catalyst that enables high yield synthesis of
perfluorinated ketones in the absence of solvent was
developed.
(2) It is shown that interaction of fluorides with
hexafluoropropylene leads to forming perfluoroisopropyl
ketones of the significantly higher yield than by reaction
of fluorides and tetrafluoroethylene with the formation
of perfluoroethyl ketones.
(3) 19F NMR spectroscopy of high resolution al-
lowed the identification of stereoisomers in the products
of addition of fluoroolefines to perfluoro-2-methyl-3-
(b) pefluoro-(2-methyl-3-oxahexanoyl) fluoride (IV):
by condensation of II with HFPO on potassium fluoride
in environment of diethylene glycol dimethyl ether (di-
glyme) extracting by distillation the product with 98 wt%
content;
(c) perfluorocyclohexane carbonyl fluoride (VI): by
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 86 No. 8 2013