Development of technology of perfluoroethyl isopropyl ketone production

Article abstract of DOI:10.1134/S1070427213030154

Synthesis of perfluoroethyl isopropyl ketone by an interaction of hexafluoropropene with perfluoropropionic acid fluoride or hexafluoropropene oxide was examined. Interchangeability of perfluoropropionic acid fluoride and hexafluoropropene oxide was demonstrated. The features of perfluoroethyl isopropyl ketone synthesis were studied in polar aprotic solvents on catalysts: alkali metal fluoride. A method for obtaining perfluoroethyl isopropyl ketone by direct catalytic reaction in a tubular reactor without use of solvents was suggested and investigated. The mechanism of interaction was considered. The main impurities resulting in obtaining perfluoroethyl isopropyl ketone were determined. The methods of cleaning perfluoroethyl isopropyl ketone were worked out.

Full text of DOI:10.1134/S1070427213030154

ISSN 1070-4272, Russian Journal of Applied Chemistry, 2013, Vol. 86, No. 3, pp. 376−386. © Pleiades Publishing, Ltd., 2013.
Original Russian Text © I.M. Fenichev, Yu.I. Babenko, T.A. Bispen, D.D. Moldavskii, 2013, published in Zhurnal Prikladnoi Khimii, 2013, Vol. 86, No. 3,
pp. 406−417.
ORGANIC SYNTHESIS
AND INDUSTRIAL ORGANIC CHEMISTRY
Development of Technology
of Perfluoroethyl Isopropyl Ketone Production
I. M. Fenichev, Yu. I. Babenko, T. A. Bispen, and D. D. Moldavskii
FSUE RSC “Applied Chemistry,” St. Petersburg, Russia
e-mail: htf1352501@rambler.ru
Received October 12, 2012
Abstract—Synthesis of perfluoroethyl isopropyl ketone by an interaction of hexafluoropropene with perfluoro-
propionic acid fluoride or hexafluoropropene oxide was examined. Interchangeability of perfluoropropionic acid
fluoride and hexafluoropropene oxide was demonstrated. The features of perfluoroethyl isopropyl ketone synthesis
were studied in polar aprotic solvents on catalysts: alkali metal fluoride. A method for obtaining perfluoroethyl
isopropyl ketone by direct catalytic reaction in a tubular reactor without use of solvents was suggested and inves-
tigated. The mechanism of interaction was considered. The main impurities resulting in obtaining perfluoroethyl
isopropyl ketone were determined. The methods of cleaning perfluoroethyl isopropyl ketone were worked out.
DOI: 10.1134/S1070427213030154
Perfluoroethyl isopropyl ketone С F –C(O)–i-C F
3 7
hereinafter ketone) in recent years is of heightened
The process was carried out in an autoclave at a
temperature form 20 using CsF to 85°C when using KF
as a catalyst. Yield of ketone was 58–63.5%. Primarily,
an issue of raw materials should be solved in developing
the method suitable for a technology of the ketone produc-
tion. Pentafluoropropionic acid fluoride in our country is
not produced, but it is relatively easy can be obtained by
isomerization of hexafluoropropene oxide (HFPO) [6–8]:
2
5
(
interest in connection with its fire extinguishing agent
properties [1]. In addition, it is a valuable intermediate
product for obtaining a number of organofluorine com-
pounds and also effective solvent [2]. An interaction of
hexafluoropropene (HFP) with perfluoropropionic acid
fluoride (PFAF) catalyzed by alkali metal fluoride in
aprotic polar solvents, diglyme or acetonitrile, is the main
method for the ketone synthesis [3–5]:
O
MF
F3C
FC
CF2
F3C
CF2
C
O
F
O
F3C
CF CF2 + F C
CF2
C
3
For this process as well as for the ketone obtaining the
alkali metal fluorides KF and CsF are used as catalysts.
Moreover, HFPO isomerization and ketone synthesis oc-
cur under the same conditions. In the case of PFAF and
HFPO alkali metal perfluoropropionate is formed first
F
O
C
CF3
CF3
KF, CsF
Solvent
F3C
CF2
FC
[5], which then reacts with HFP:
F3C
F3C
FC
CF2
O
C
O
F2
CF3
+CF3
CF
CF2
MF
F3C
CF2
C
F3C
CF2
FC
OM
CF3
O
CF2
C
F
3
76

DEVELOPMENT OF TECHNOLOGY OF PERFLUOROETHYL ISOPROPYL KETONE PRODUCTION 377
Therewith presumably, the rate of perfluoropropionate
formation is much higher in both cases than that of
interaction of perfluoropropionate with HFP. Ketone
synthesis of HFPO and PFAF occurs without visible dif-
ferences in the process rate, composition, and ratio of the
products: this fact is a unique case of interchangeability
of raw materials. Further this made it possible to com-
bine the isomerization of HFPO and ketone synthesis [9].
In the study of the ketone synthesis it was found that
its output depended strongly on the water content in the
solvent. The dependence of the ketone output on the
water content in acetonitrile (water content in CsF, KF
c ≤ 0.001 wt%) is shown below:
Water content in the solvent, wt%
0.01
63.5
0.02
61.5
0.04
60.2
0.06
54.3
0.09
45.0
0.16
34.0
0.18
28.5
>0.18
22
Yield of perfluoroethyl isopropyl ketone , wt%
The output reducing is explained by a formation of
an MF·HF complex, which has no catalytic activity. This
complex was formed in the interaction of PFAF with
water as can be seen from the data.
can reach 30%. Synthesis of HFP and HFPO dimers was
carried out in conditions similar to those for the ketone
[10]. Along with them, 6.5% of high-boiling compounds
were formed. The discharged catalyst were of yellow-
brown color, its dissolving in water gets resinous film.
These compounds encapsulate crystals of metal fluoride
reducing its catalytic activity by 30–50% that makes nec-
essary to use a freshly prepared catalyst in each synthesis:
The process of ketone obtaining is accompanied by the
formation of by-products, mainly, 2-perfluoromethylpen-
tene (HFP dimer) and perfluoro-2-methyl-3-oxahexanol
fluoride (HFPO dimer). Their total content in the crude
O
CF3
F C
3
KF
F3C FC
CF2 + F C CF
CF2
F3C CF2
C
FC
+
CF CF2
18%
CF CF2
3
diglyme
F3C
O
CF
3
63.5%
O
F
+
F2C
C
CF2
CF2
CF3 + F C CF2
CF O
CF
CF3
C
+ undetermined products
6.5%
3
2
CF3
2
.3%
9.7%
The ketone isolation by distillation is ineffective since
boiling point of the ketone, HFP, and HFPO dimmers are
separated from the crude ketone, practically insoluble in
water. It should be noted that aqueous solution of these
acids is highly corrosive. This fact should be accounted
for in the process designing. Alkaline solutions can be
applied for reducing the corrosivity, e.g., solutions of
soda (or baking soda), but hydrolysis of the most ketone
becomes notable in alkaline environment:
4
8.5, 46–51, and 56°С, respectively.
The HFPO dimer as well as all fluorides of
perfluorocarboxylic acid reacts vigorously with water
and can be easily removed from the reaction mixture by
hydrolysis [11]:
O
O
F3C
CF2
CF O
CF
C
CF3
2
CF3
CF2
CCF
F
CF3
CF3
O
H O (Ph =
8 14)
2
O
O
_
F3C
CF2
CF O
CF
C
+ HF
2
H O
2
F3C
CF2
C
+
F3C
C
OH
OH
OH
CF3
Resulting mixture of perfluoro-2-methyl-3-oxohexa-
noic and hydrofluoric acids is very soluble in water and
+
CF3
CFH
CF3
+
CF3
CF H
2
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 86 No. 3 2013

378
FENICHEV et al.
Figure 1 shows results of the ketone hydrolysis study
in aqueous solutions of different acidity.
For the separation of the ketone from HFPdimer [11],
the latter can be turned into high-boiling compounds,
e.g., into 2-perfluoromethyl-2-chloroperfluoropentane
(
bp 83°C) by reaction with monofluorochlorine or into
,2-dihydro-2-perfluoromethylpentane (bp 71°C) by
hydrogenation on palladium catalyst:
1
F2C
C
CF2 CF2
CF3
CF3
Fig. 1. Hydrolysis of the ketone at 20°C. The volume ratio of
ketone : solution = 1 : 5, stirring speed 350 rpm. (α) degree of
hydrolysis of PFEIK (%).
ClF
F3C
CCl CF2 CF2
CF3
CF3
–
A relatively low output of ketone: less than 63.5%;
F2C
C
CF2
CF2
CF3
– A large number of impurities of HFPO and HFP
dimers: up to 30 wt%, necessitates including hydrolysis
and hydrogenation units, respectively, for their separation;
CF3
H2
.2% Pd/C
HF C
CH
CF3
CF2 CF2
CF3
– Cyclicity of the process and the need to operate
under the pressure of 0.5–0.7 MPa;
2
0
–
The need for disposal of large quantities of waste,
including, possibly, toxic.
These compounds are relatively easily separated
from the ketone by distillation. Both reactions proceed
quantitatively at 20°C and the ketone remains practi-
cally unchanged. In view of the high aggressiveness
of monofluorochlorine and the need for creation of its
preparation unit we selected hydrogenation of HFPdimer.
Hydrogenation was carried out in a vertical reactor filled
with activated carbon SKT-6 coated with a palladium.
New alternative ways of the ketone synthesis should
be developed due to the difficulties, which complicate and
make the process expensive, and first the solvents should
be eliminated. Thus, it should be created a highly selective
catalyst, which would eliminate or at least significantly
reduce the content of impurities, especially HFPO and
HFP dimers possessing similar boiling points. A number
of fluorine-containing compounds, as well as activated
carbons and compositions based on them were tested as
catalysts. The results are listed in Table 1.
On the basis of the research a pilot plant of ketone
–1
production with output of 5 kg day was constructed with
the target product purity 99.6–99.95%. The plant included
the following stages: preparation of the starting mixture,
the catalyst and solvent charging, the ketone synthesis,
hydrolysis of HFPO dimer, drying, hydrogenation of
HFP dimer on a palladium catalyst, and distillation of
the crude.
As can be seen from Table 1 catalyst CsF supported
on activated carbon BAU-2, K-3, SKT-6 and prepared at
2
00°C demonstrates the best results. As the production
of carbon AG-3 and SKT-6 is currently suspended and
carbon BAU-2 is widely used and relatively cheap prod-
uct, further research has conducted on activated carbon
BAU-2. This catalyst significantly reduced the forma-
tion of by-products, especially HFPO and HFP dimers
and allowed carrying out the process at 130°C with the
output of up to 92% [12]. Use of a catalyst KF together
with CsF, deposited on activated carbon, may reduce the
concentration of expensive CsF and increases the ketone
content in the raw material [13].
Although the method for the ketone synthesis
in aprotic polar solvents and developed ways of its
cleaning allow obtaining the ketone of 99.9% pu-
rity there exist significant shortcomings that impede
implementation of this method on an industrial scale:
–
The need for drying solvents to a residual water
content of less than 0.08 wt%;
The fresh catalyst and solvent are required in each
synthesis;
–
At the same temperature, the isomerization of HFPO
into PFAF occurs.
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DEVELOPMENT OF TECHNOLOGY OF PERFLUOROETHYL ISOPROPYL KETONE PRODUCTION 379
Table 1. Catalytaic methofd of perfluoroethyl isopropyl ketone symthesis
Content of the
Ketone
Impurities content, wt%
ketone in the
raw material
yield
Catalyst
T, °С
low-boiling
acidic
perfluoro-2-methyl-3-
oxahexanol fluoride
2-perfluoro
methyl pentene
wt%
CsF
130
14.8
30.29
20.8
10.3
5.6
0.19
0.21
0.64
0.6
0.05
0.1
0.06
0.1
5.1
5.9
5.0
0.8
0.2
85.0
69.4
78.5
89.0
73.5
58.6
73.7
72.5
70.6
12.4
13.8
21.6
77.6
64.0
52.0
64.2
62.0
60.3
1
80
CaF + NaF + KF
130
130
130
2
CaF + NaF + CsF
2
Activated carbon BAU-2
15.8
16.5
15.7
1.2
1
60
19.0
5.6
Activated carbon SKT-6
130
KF on activated carbon BAU-2 130
60
KF on activated carbon BAU-2 130
25.5
28.0
1
1.2
24.1
5.9
1.2
0.5
0.2
0.1
74.5
93.5
62.6
91.1
2
% CsF on activated carbon
130
BAU-2
5
–20% CsF on activated car-
130
5.8
0.1
0.05
94.0
92.0
bon BAU-2
1
60
13.9
5.6
0.1
0.1
0.05
0.05
86.0
94.3
83.0
92.2
5
–20% CsF on activated car-
130
120
bon SKT-6
KF + CsF (10% KF + 10%
CsF) on activated carbon
BAU-2
0.15
0.47
0.08
99.3
92.0
However, further study showed, that at this tempera-
ture degradation and polymerization are accelerated and
an efficiency of the catalyst and, thus, the ketone yield
decrease:
The resulting polymer (PTFE) blocks the
nucleophilic sites of the carbon surface of the catalyst
and significantly lowers (by 40–55%) its catalytic
activity. Such catalyst allows operation up to 200 hours.
O
F
o
T > 125 C
F3C FC
CF2
F3C CF2
C
F3C CF + [CF2:]
O
CsF/Activated carbon
O
+CF3
CF
CF2
F2C
CF2
O
O
C
CF3
CF3
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 86 No. 3 2013
CF3
CF3
F2C CF2
F3C CF2
C
FC
F3C
FC
n

380
FENICHEV et al.
The catalyst structure was studied by electron probe
microanalysis. It was found that the catalyst prepared at
Further investigation was required for developing a
catalyst effective at low temperatures, providing conver-
sion 99% or more, and maintaining activity for more than
200 hours. The catalyst activated at 320–350°C under
vacuum with periodic nitrogen purging, does not contain
2
00°C contains a complex CsF·H O, which in the course
2
of isomerization of HFPO into PFAF turns into complex
CsF·HF possessing no catalytic activity:
O
CsF H O/Activated carbon
2
F3C FC
CF2
F3C CF2
C
O
F
O
F
O
CsF H O
+
F3C CF2
C
CsF HF
+
F3C CF2
C
2
OH
this complex since it is decomposed:
thesis (from 130 to 65–95°C) and isomerization of HFPO
into acid fluoride (from 120–130 to 45–60°C), also the
formation of by-products is reduced.
_
o
T = 320 350 C
CsF HF
CsF + HF
Micrographs of CsF catalyst samples prepared at dif-
ferent temperatures and supported on activated carbon
BAU-2 are shown in Fig. 2. Figure 2 demonstrates that
in the catalyst obtained at 350°С CsF crystals are placed
on the catalyst surface and not inside as in sample no. 1.
The high efficiency of CsF catalyst on activated carbon
enables conducting the ketone synthesis by interaction
of HFPO with HFP in the tubular reactor at sufficiently
high rates of the process at 65–95°С with the yield of
upto 95%:
Results of X-ray microanalysis are shown in Table 2.
In addition, an alternation of nitrogen purge of the
catalyst with evacuation at 320–350°C contributes to
dispersing CsF crystals to less than 100 nm, and submit
the catalyst to the surface of the active sites of activated
carbon that significantly increases its catalytic efficiency.
A technique of activation of the catalyst was developed.
Obtained catalyst retains catalytic activity for 800 hours
of operation, reduces the temperature of the ketone syn-
O
CF3
CsF/Activated carbon
F3C FC
CF2 + F C
CF CF2
F3C CF2
C
FC
3
_
o
T = 65 95 C
O
CF3
Experimental data are listed in Table 3.
spectively. Its value is consistent with the ordinary values
of heats of adsorption of substances on porous catalysts.
This indicates that the reaction is controlled by the ad-
sorption step of the initial reagents. The proximity of the
In examination of macrokinetics of the interaction of
HFP with HFPO or PFAF it was found that a calculated
activation energy was 7.683 and 7.185 kJ mol K , re-
–
1
–1
Table 2. Results of X-ray microanalysis
Content, wt%
Activation temperature, °С
Cs/F
Formulaa
S
K
Ca
0.7
0.5
Cs
5.2
6.3
F
2
3
00
0.2
0.1
0.3
0.4
1.5
0.9
3.5
7.0
CsF·HF
CsF
20–350
a
Correspond to the obtained stoichiometric ratio.
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 86 No. 3 2013

DEVELOPMENT OF TECHNOLOGY OF PERFLUOROETHYL ISOPROPYL KETONE PRODUCTION 381
No. 1
1
00 μm
10 μm
No. 2
1
00 μm
10 μm
Fig. 2. Micrographs of catalyst samples prepared at 200°C (no. 1), 350°C (no. 2).
activation energy of interaction of hexafluoropropene
with both HFPO and PFAF confirms that both processes
are interchangeable and proceed in the same conditions
action volume in the course of the reaction: in this case
vortex flows are reduced and side processes decreases
[14]. Implementation of the device, which automatically
reduces the volume upon the reaction course, is possible
when the process occurs in a flow conical reactor, whose
area of an inlet cross section is about twice the outlet.
(temperature, contact time, conversion, and composition
of raw material).
A mechanism of interaction proceeding through the
formation of intermediate complex (cesium perfluoropro-
pionate), which then reacts with HFPforming the ketone,
was suggested based on the studies.
Implementation of the advantages of the conical reac-
tor under industrial conditions was not possible: a straight
flow-through device was used in the development of the
technology, however, it was successfully used to study
the kinetics of the reaction [15, 16].
According to the results of kinetic studies a design
and specific performance of the reactor for the ketone
production were calculated that allowed designing and
constructing an industrial reactor for the product obtain-
ing at the pilot plant of FSUE RSC “Applied Chemistry.”
Measurements showed that the isomerization of HFPO
into PFAF proceeds with heat release (65.8 kJ mol–1).
In order to maintain the required temperature an isom-
erization reactor was constructed, which was a pipe
filled with a catalyst. Inside this reactor there was a heat
Since the process proceeds with a decrease in a specific
volume it is technologically appropriate to reduce a re-
Table 3. Synthesis of perfluoroethyl isopropyl ketone on the developed catalyst CsF/activated carbon
Ketone
content
Ketone
yield
Parameter of the process
The amount of impurities, wt %
HFP dimer HFPO dimer
T, °C
5–95
95
P, MPa
0.2–0.3
0.2–0.3
low-boiling
1.91
high-boiling
0.03
wt%
6
–
–
0.06
0.06
98
94
95
91
>
5.9
0.05
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 86 No. 3 2013

382
FENICHEV et al.
exchanger for removing from the reaction zone the heat
released.
2 hours. Then reactor was cooled, pressure was reset,
the reaction products were settled and separated into two
layers. The bottom layer, crude ketone and fine potassium
fluoride, was directed to filtration from the catalyst, fol-
lowed by removal of impurities of HFPO dimer. The top
layer, diglyme, was collected in the receiver and in the
course of its accumulation its recovery (distillation) was
performed: purified diglyme was for re-use.
On the basis of the research on the experimental plant
of FSUE RSC “Applied Chemistry” the pilot plant of
the ketone synthesis was constructed, comprising the
following steps: preparing a mixture of HFPO–HFP,
isomerization and synthesis of ketone, washing of raw
material with water, and rectification. The methods of the
ketone synthesis were patented [9, 12, 13, 16].
Purification of perfluoroethyl isopropyl ketone
from impurities of perfluoro-2-methyl-3-oxahexanol
fluoride. Alkaline hydrolysis. The reaction mass (8.2 kg)
was placed in a plastic container of 12 L and it was filled
with 25% caustic solution at a ratio of 1 : 2 and stirred
for 2 hours. Purifying ketone from impurities of HFPO
dimer was carried out at room temperature. Gases formed
were released. The reaction monitoring was carried out
by chromatography. Weight of the reaction mixture after
hydrolysis was 6.64 kg, the composition was: ketone
EXPERIMENTAL
Analysis of the product, intermediates was carried
out by GLC on a Crystal 2000M chromatograph with
a thermal conductivity detector, column silohrom +
2
0% α,α,α-trisbetacyanethoxyacetophenone, l = 2 m.
IR spectra were recorded on an infrared spectrophotom-
eter IRPrestige-21 (Shimadzu), the spectral range of
6
6.8%, HFPO dimer not present , dimer HFP 23.1%,
–1
19
4
000–400 cm , the F NMR spectra, on Spektrospin
high-boiling impurities 10.1%.
AM 500 (Bruker).
Crude perfluoroethyl isopropyl ketone purified from
HFPO dimer was separated on a funnel, weighed, and
analyzed, and then sent to the purification step from the
HFP dimer.
Hexafluoropropene oxide produced by JSC “Galopo-
limer,” target product content 99%, content of HFP0.4%.
Hexafluoropropene produced by “HaloPolymer,” target
product content 99.9 wt% and more.
Acidic hydrolysis. In a reactor with stirrer made of
Teflon 4, the reaction mass (8.2 kg) after a synthesis step
and water were charged in a ratio of 1 : 5. In the hydroly-
sis the reaction medium becomes acidic to pH 2–3. The
process was carried out with constant stirring for 6 h. The
reaction mixture weight after hydrolysis was 7.3 kg, the
composition was: PFEIK 71.7%, HFPO dimer not pres-
ent, HFPdimer 19.2%, high-boiling impurities 9.1%. Raw
ketone was separated from the water and directed to the
removal of impurities of HFP dimer.
CsF and KF of analytical purity were dried in a plati-
num crucible at 500°C for 6 h, cooled in a desiccator,
ground, and finally dried in vacuum at 250°C to a residual
moisture content of 0.001 wt% or less. Solvents (diglyme,
acetonitrile) were dried by calcined zeolite of CaAgrade
to a residual water content of 0.01 wt% or more.
Synthesis of perfluoroethyl isopropyl ketone in po-
lar aprotic solvents. In a 18 L cylindrical reactor made
of steel 12Kh18N10T equipped with a Gopher valve, ma-
nometer, magnetic stirrer, loading bubbler, and electrical
heater, 5.3 L of acetonitrile or diglyme was charged and
then 250 g of dry KF was added. Afterwards the stirrer
was switched on and 85.52 g of HFPO was fed to the
reactor from a cylinder (catalyst activation).
Purifiaction of perfluoroethyl isopropyl ketone
from impurities of 2-perfluoromethyl pentene. Chloro-
fluoridation. In the reactor (a vertical column of a 0.75 m
length and 0.03 m diameter equipped with a cooling jacket
and filled with nickel Raschig rings) the raw ketone con-
taining 19.2 wt% of HFPdimer was dosed by a measuring
The feed of HFPO was monitored by the cylinder
weight. After HFPO feeding completion the reactor
content was stirred for 2 h without heating.
–
1
tank-metering at a rate of 400–530 g h . Simultaneously
to the bottom of the column ClF (97 wt% purity) ob-
tained by the method described in [17] was fed at a rate
The reactor was evacuated to a residual pressure of
–
1
5
0 mm and then heated to 65–80°C and the mixture of
of 5–6.5 L h at a temperature in the jacket –5…–10°C.
The raw ketone effluent from the column was collected
in a receiver. The reaction was monitored by chroma-
tography. The composition of the reaction mixture after
chloro-fluoridation and washing with baking soda was:
HFP and HFPO was fed with constant stirring in a molar
ratio of 1.03 : 1 for 6 hours avoiding an increased pres-
sure above 0.7 MPa. After addition of the mixture in
an amount of 8.3 kg the reactor content was stirred for
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DEVELOPMENT OF TECHNOLOGY OF PERFLUOROETHYL ISOPROPYL KETONE PRODUCTION 383
Catalyst
Solvent
Water
Water
Zeolite
Catalyst to regeneration
Fig. 3. The laboratory setup for perfluoroethyl isopropyl ketone in aprotic polar solvents. (1) Cylinder HFP; (2) cylinder HFPO; (3) mixer,
4) reactor, (5, 8) separators, (6) filter, (7) hydrolysis unit, (9) collection, (10) hydrogenation reactor, (11) drier, (12) fractionation unit.
(
ketone 68.2%, HFP dimer not present, С F Cl 19.2%,
high-boiling impurities 12.6%. The isolated product of
with a catalyst (Pd 0.2%/BAU-2), raw ketone containing
19.2% of HPF dimer was dosed at the rate of 350–600 g
6
13
–
1
chloro-fluoridation (С F Cl) was of boiling point 83°C,
h . Simultaneously to the bottom of the column hydro-
6
13
–
1
which corresponded to the data in [18].
gen was fed at a rate of 4.2–6.5 l h at a temperature in
the jacket –5…–10°C. The raw ketone effluent from the
column was collected in the receiver. The reaction was
monitored by chromatography. The composition of the
Hydrogenation. In a reactor (a vertical column of
a 0.8 m length and 0.25 m diameter equipped with a
cooling jacket, measuring tank-metering, and filled
Table 4. 19F NMR spectrum
Carbon atom
Number
of nuclei F
Structure of compound
–δ
, ppm
Multiplet
JF*–F**, Hz
СCl F
no.
3
1
4
1
3
1
72.5
6
3
1
1
d.t
d
F –F 6.8; F –F 2.9
O
2
4
2
80.8
119.1
189.2
F –F 6.4
2
3
4
CF CF CCFCF
3
2
3
3
4
3
1
3
d.q
t.sx
F –F 28.7; F –F 2.8
CF31
4
3
4
1
4
F –F 28.8; F –F 6.8
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384
FENICHEV et al.
reaction mixture after hydrogenation was: ketone 71.3%,
HFP dimer not present, С F Н 19.2, high-boiling
components was controlled by weighing the cylinders.
6
12
2
Liquid mixture of HFP and HFPO was fed at a con-
stant rate to an evaporation feeder, a pipe of a 450 mm
length and 36 mm diameter, which was heated to 40°C,
afterwards the mixture entered the isomerization unit
impurities 9.5. The isolated product of hydrogenation
С F Н ) was of boiling point 71°C, which corresponded
(
6
12
2
to the data of [18].After completion of the hydrogenation
the raw ketone (5.5 kg) was dried over calcined zeolite of
CaA grade, then it was distilled. The experimental setup
is shown in Fig. 3. Ketone yield of purity 99.9 wt% was
(Fig. 4). The isomerization unit was a heated cylindrical
container with a two-piece heating of a 600 mm length
and 76 mm diameter with a supply of the reaction mixture,
withdrawal of the reaction products, and water supply to
the heat exchanger built into the center of the isomeriza-
tion unit to remove heat from the reaction zone. In the
isomerization unit isomerization of PFAF into HFPO
and partial interaction of PFAF with HFP with the for-
mation of the ketone occur. The reaction mixture from
the isomerization unit was directed to a main synthesis
reactor, which was a cylindrical container with the two-
piece heating of a 1500 mm length and 70 mm diameter.
4
.9 kg.
Identification of obtained perfluoroethyl isopropyl
ketone [CF CF C(O)CF(CF ) ]. There is a charac-
3
2
3 2
teristic absorption band for ketones in the IR spectrum
–
1
(
(
[
1780 cm ). Mass spectrum, m/z: 69 (CF +), 100
3
C F +), 119 (CF CF +), 147 [CF CF C(O) +], 169
(CF ) CF+], 197 [(CF ) CFC(O)+]. F NMR spectrum
2
4
3
2
3
2
19
3
2
3 2
of the obtained compound is shown in Table 4.
Production of perfluoroethyl isopropyl ketone by
the direct catalytic interaction. Before starting of the
operation in the mixer mixture of HFP and HFPO in a
molar ratio of 1.03 : 1 was prepared.An amount of loaded
In the reactor and isomerization unit the prepared
catalyst was preloaded (cesium fluoride supported on
activated carbon BAU-2). HFPO was fed up to 0.3 MPa
Purging
Water
Water
Water
Fig. 4. The laboratory setup for perfluoroethyl isopropyl ketone in a flow mode. (1) Cylinder HFPO; (2) cylinder HFP; (3) Mixer, (4)
evaporator dosing, (5) isomerization unit, (6) reactor with two sectional heating, (7, 8) heat exchange devices, (9) receiver of raw, (10)
absorber, (11) apparatus for cleaning from acid impurities, (12) cube of column, (13) distillation column, (14) reflux, (15) a receiver of
intermediate fraction, (16) a receiver of the finished product.
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DEVELOPMENT OF TECHNOLOGY OF PERFLUOROETHYL ISOPROPYL KETONE PRODUCTION 385
and kept for 2 hours for activation the catalyst.
ation of heat loss to the environment was made relative
to the rate of temperature falling in a saline solution
pre-heated to 80°C after disconnecting the heat source.
–
1
The resulting mixture was fed at a rate of 1.2 kg h at
a temperature of 80–95°C and a pressure of 0.25–0.3 MPa
for 7 h. The reaction product was collected in a receiver
cooled to –10°C. The reaction products were weighed
–
1
Cooling rate did not exceed 0.5° h that corresponded to
a power loss Q = 0.01(T – T ), W, and did not exceed
av
av
1
0% of the power dissipation).
(
8.05 kg), analyzed by chromatography, and directed
to the washing step from acid impurities in the device
with a stirrer. Washing was performed for 2 h at a ratio
of crude PFEIK : water = 1 : 4. After washing the raw
ketone (7.8 kg) was directed to the distillation.
Then, the starting product, HFPO, was passed through
the reactor also placed in a liquid medium. The reactor
was a U-shaped pipe filled with the catalyst CsF deposited
on activated carbon (pre-dried at T = 250° C and activated
by passing the initial product at T = 80–90°C).
For distillation a steel distillation column was applied
filled with nichrome helices. A column height was 2 m;
outer diameter, 0.052 m; a volume of a cube, 18 dm .
HFPO was passed through the reactor for 4.75 h at
a constant flow g = 39.58 g h , and every 15 minutes
3
–1
A column reflux was cooled to –15…–20°C. Pressure
on the column was maintained from 0 to 0.05 MPa. The
temperature in the cube must be controlled so as to ensure
an optimal mode of the column.
a temperature increase of liquid due to heat release was
recorded.
In the course of the isomerization of HFPO the tem-
perature of aqueous solution increased from initial T =
0
In the laboratory pilot plant 60 kg of PFEIK samples
were obtained with basic substance content 99.99%.
60°C to 71.7°C.
In the process the composition of products at the reac-
tor outlet was analyzed several times. Chromatographic
analysis showed that the isomerization during product
residence in the reactor proceeded with a conversion of
above 99% and with a fairly good selectivity (> 90%).
The main part of the laboratory plant is shown schemati-
cally in Fig. 5.
Determination of heat of isomerization. Insulated
dewar with evacuated walls was filled with 25% solu-
tion of sodium chloride (bp 107°C). Liquid mixing was
carried out with a magnetic stirrer. Inner temperature
measurement was performed by a mercury thermometer
with an accuracy of ±0.05°.
The calorimeter was previously calibrated in the op-
erating temperature range (T = 60–80°C) with the help of
a spiral heater of variable power, which is fixed. (Evalu-
The determined heat of reaction of HFPO into acid flu-
–1
oride in view of an error was Q = 65.78 ± 3.35 kJ mol .
r
CONCLUSIONS
AF
Tout
Synthesis of perfluoroethyl isopropyl ketone by the
interaction of perfluoropropionic acid fluoride with hexa-
fluoropropene and of hexafluoropropene oxide with hexa-
fluoropropene was investigated. The interchangeability
of hexafluoropropene oxide and perfluoropropionic acid
fluoride was demonstrated.
HFPO
Tin
It was shown that the yield of the product using the
aprotic polar solvents depends on the preparation of the
catalyst and solvents and does not exceed 63.5%. The
methods of isolation of perfluoroethyl isopropyl ketone
from the reaction mixture by hydrolysis of the reaction
mixture and subsequent hydrogenation on the catalyst
(palladium) supported on activated carbon, were devel-
oped, which allowed obtaining the target product with a
purity of 99.95 wt% and content of 2-perfluoromethyl
pentene no more than 20 ppm.
Fig. 5. Determination of heat effect of the isomerization of
HFPO to acid fluorides.
An efficient method of the direct catalytic produc-
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 86 No. 3 2013

3
86
FENICHEV et al.
3. US Patent 3185734, 1965.
tion of perfluoroethyl isopropyl ketone by interaction of
hexafluoropropene with perfluoropropionic acid fluoride
or hexafluoropropene oxide.
4
5
. US Patent 4136121, 1979.
. Kolenko, I.P., Plashkin, V.S., and Ovchinnikov, G.F., Zh.
Vses. Khim. Obshch im. D.I.Mendeleeva, 1974, vol. 19,
p. 707.
An efficient highly selective catalyst cesium fluoride
deposited on activated carbon BAU-2, AG-3 or SKT-6
was developed in an amount of 5–20 wt% of carbon. The
catalyst enables production of perfluoroethyl isopropyl
ketone at 65–95°C and provides operation time up to
6. Japan Inventor’s Certificate 58-35978; Izobr. v SSSR i za
rubezhom, 984, vol. 57, no. 8, p. 130.
7
8
9
. Japan Patent 58-38231, 1984.
. US Patent 5684193, 1997.
. RF Patent 2472767, 2013.
8
00 hours.
The macrokinetics of the interaction of hexafluoro-
propene with both perfluoropropionic acid fluoride and
hexafluoropropene oxide was examined, the optimal
conditions of perfluoroethyl isopropyl ketone synthesis
were established, the mechanism of interaction proceed-
ing via alkali metal perfluoropropionate formation was
suggested, the reactor for the pilot plant of production of
perfluoroethyl isopropyl ketone was calculated.
1
0. Chambers, R.D., J. Chem. Soc. C, 1968, p. 2221.
11. Moldavskii, D.D., Fenichev, I.M., Babenko, Yu.I., et al.,
Onlain. Zh. Ftornye Zametki, 2011, no. 6.
2. RF Patent 2460717, 2012.
1
1
3. RF Patent 2011141150/04 (061510).
14. Kochin, N.E., Kibel’, I.A., and Roze, N.V., Teoreticheskaya
gidromekhanika (Theoretical Hydromechanics), Moscow:
GIFML, 1963.
The pilot setup for production of perfluoroethyl iso-
propyl ketone in the pilot plant of FSUE RSC “Applied
chemistry” was designed and created.
1
5. Moldavskii, D.D., Fenichev, I.M., Babenko, Yu.I., et al.,
Onlain. Zh. Ftornye Zametki, 2012 no. 3.
1
1
6. RF Patent 107073, 2011.
REFERENCES
7. Handbuch der Praparativen Anorganischen Chemie,
1
2
. German Patent 1973864, 2009.
Brauer, G., Ed., Ferdinand Enke Verlag, Stuttgart, 1978.
. Furin, G.G., Zh. Org. Khim., 1994, vol. 30, no. 11,
18. P&M Invest. Catalog of Fluorine Compounds 2006–2008,
pp. 1704–1758.
Moscow, 2006, pp. 37, 107.
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 86 No. 3 2013