Novel synthetic route to perfluoroallyl cyanide (PFACN) reacting perfluoroallyl fluorosulfonate with cyanide

Article abstract of DOI:10.1016/j.jfluchem.2018.03.003

A novel synthetic method for the preparation of perfluoroallyl cyanide CF₂[dbnd]CFCF₂CN (PFACN) is presented. This includes the addition – elimination reaction of cyanide anion with perfluoroallyl fluorosulfate CF₂[dbnd]CF

Full text of DOI:10.1016/j.jfluchem.2018.03.003

Accepted Manuscript
Title: Novel synthetic route to perfluoroallyl cyanide (PFACN)
reacting perfluoroallyl fluorosulfonate with cyanide
Authors: Sergey N. Tverdomed, Markus E. Hirschberg,
Romana Pajkert, Klaus Hintzer, Gerd-Volker Ro¨schenthaler
PII:
S0022-1139(18)30036-8
DOI:
Reference:
https://doi.org/10.1016/j.jfluchem.2018.03.003
FLUOR 9131
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FLUOR
Received date:
Revised date:
Accepted date:
23-1-2018
2-3-2018
6-3-2018
Please cite this article as: Tverdomed SN, Hirschberg ME, Pajkert R, Hintzer K,
Ro¨schenthaler G-V, Novel synthetic route to perfluoroallyl cyanide (PFACN) reacting
perfluoroallyl fluorosulfonate with cyanide, Journal of Fluorine Chemistry (2010),
https://doi.org/10.1016/j.jfluchem.2018.03.003
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Novel synthetic route to perfluoroallyl cyanide (PFACN) reacting perfluoroallyl
fluorosulfonate with cyanide
Sergey N. Tverdomeda*, Markus E. Hirschbergb**, Romana Pajkerta, Klaus Hintzerb, Gerd-
Volker Röschenthalera
a
Life Sciences & Chemistry, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
3M Advanced Materials Division, Dyneon GmbH, Industrieparkstr. 1, 84508 Burgkirchen, Germany
b
* Corresponding author.
**
Corresponding author at: 3M Advanced Materials Division, Dyneon GmbH, Industrieparkstr. 1, 84508 Burgkirchen,
Germany.
E-mail addresses: s.tverdomed@jacobs-university.de (S.N. Tverdomed), mhirschberg@mmm.com (M.E. Hirschberg).
The Graphical abstract:
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Highlights:
 a novel synthetic method for the preparation of PFACN
 by 19F-,13C-NMR and IR spectroscopy characterized
 by MS-spectrometry characterized
 up to 30% isolated yield
 optimized reaction conditions
Abstract: A novel synthetic method for the preparation of perfluoroallyl cyanide CF2=CFCF2CN
(PFACN) is presented. This includes the addition – elimination reaction of cyanide anion with
perfluoroallyl fluorosulfate CF2=CFCF2OSO2F (PFAFS). The reaction conditions, factors affecting
the reactivity and regioselectivity of the process, the choice of reagent as well as the course of
competitive reactions are discussed, too.
Keywords: perfluoroallyl fluorosulfate, perfluoroallyl cyanide, addition/elimination reactions,
cyanide anion.
1. Introduction
In recent years, unsaturated perfluorinated nitriles have found important application in
the synthesis of selected amorphous fluoroplastics such as crosslinkers (Fig. 1). However, among
the co-polymers of this class described in literature, nitriles containing the perfluorovinyl moiety
are of great interest (A and B) [1-3]. The classical unsaturated perfluorinated nitriles are represented
by only one example, namely perfluoroallyl cyanide (C, Fig. 1). This compound can be used
successfully for the synthesis of amorphous tetrafluoroethylene-hexafluoropropylene copolymer as
well as in the preparation of films, coatings, additives, encapsulants, and mold release agents [4-7].
PFACN also finds application for plasma etching silicon-containing films to produce electronic
components or semiconductor devices [8-9].

Fig. 1. Some examples of unsaturated perfluorinated nitriles as copolymers for amorphous fluoroplastics
However, very few examples of synthetic routes to PFACN have been described and only two
reports could be found in the literature as shown in Fig. 2 [10-11]. In the first example, PFACN was
obtained by dechlorination of 3,4-dichloropentafluoro butyronitrile with zinc in dioxane [10]. In the
second example, PFACN was synthesized upon treatment of 3-chloro-1,1,2,3,3-pentafluoroprop-1-
ene with sodium cyanide (NaCN) in aqueous tert-butanol [11]. However, in both cases the literature
sources have not provided any information about the isolated yield of the products as well as the
spectral characteristics of PFACN. Moreover, the description of the synthetic procedure has either
not been presented [10] or published with limited information [11]. In addition, the determined
boiling points of PFACN differ significantly, namely 26 °C for ref. [10] and 43 – 48 °C for ref.
[11], respectively. Certain doubts about the reliability of the results have been also caused by using
water as the reaction medium in the synthesis of PFACN [11]. Therefore, the important role of
PFACN in industrial polymerization processes [1-7], the inaccessibility of its known precursors
[10-11], as well as the inconsistency of the described methods [10-11], renders the search for a
convenient method of obtaining PFACN an actual research objective.

Fig. 2. Previous works and current work
It is well known that perfluoroallyl fluorosulfate (PFAFS) is a convenient building
block for the preparation of various fluoroallyl compounds [12-13]. The fluorosulfate group is a
good leaving group and could be easily replaced by a variety of nucleophilic reagents. This process
is usually conducted through addition of a nucleophile to the double bond of PFAFS, prior to the
elimination of the fluorosulfate anion (Scheme 1). As nucleophiles, various alcohols, phenols,
perfluoroalcoholates, azides and halides could be applied [12]. Furthermore, no examples for
reacting PFAFS with cyanide anion sources have been described, so far. For the first time a
convenient production of PFACN via the reaction of PFAFS with cyanide is reported.
2. Results and discussion
2.1. Preparation
Perfluoroallyl fluorosulfate (PFAFS) actively reacts with sodium cyanide to form
perfluoroallyl cyanide (PFACN) as the main product. The reaction was carried out by slow addition
of PFAFS 1 to a suspension of NaCN in an organic solvent (Scheme 1) to furnish PFACN 2 in 24 –
27 % yields (Method A). The reaction was highly exothermic possessing a cumulative effect. If the
temperature of the reaction mixture was raised above -10 °C, an uncontrollable process was
initiated that spontaneously increased the temperature of the reaction mixture up to 75 – 80 °C.
Moreover, destruction and polymerization of 1 occured, and product 2 was not detected even in
traces. The optimal temperature should be around -16 ÷ -10 °C (Table 1, entries 1 and 2) and the
selectivity of the reaction of NaCN with PFAFS 1 strongly depends on the solvent. Hence, a wide
range of different solvents, such as water, acetonе, acetonitrile (CH3CN), methanol (CH3OH),
diglyme (DG), triglyme (TG), dichloromethane (DCM), Hostinert-216, N-methyl-2-pyrrolidone
(NMP), as well as a mixture of solvents (CH3CN/H2O) were tested. The best results were obtained
using aprotic solvents of medium polarity including CH3CN or TG. As a result, compound 2 was
obtained in 27% and 18% yield, respectively (entries 1 and 3). In the case of highly polar NMP, the
reaction proceeded non-regioselectively and according to GC-MS and 19F NMR PFACN 2 was not
formed (entry 4). In the case of non-polar Hostinert-216, the reaction did not lead to completion and
the sprecursor 1 could be quantitatively recovered (entry 5). The presence of water in the reaction
mixture, even in catalytic amounts (entry 6), led to a sharp decrease in the selectivity of the process
and 2 could be only registered in traces by GC-MS (entry 7). An excess of NaCN and the choice of
solvent affected the efficiency of the reaction: in the case of acetonitrile, an increase in the amount
of NaCN from 1.1 to 1.98 equiv. led to higher yields of 2 - from 13% to 27% (entries 8 and 1).

Regarding TG as a solvent, there is an opposite trend and an increase in the amount of reagent from
1.0 to 1.95 equiv. led to a loss of yield of 2 from 18% to 11% (entries 3 and 9). Aiming to improve
the thermal control of the reaction, the order of addition of reagents was changed and pre-dried
NaCN was added to the solution of PFAFS 1 in anhydrous MeCN at -10 ° C under intense stirring.
However, after addition of the first portion of NaCN, no visual effects of the process were
observed. To avoid an uncontrollable exothermic reaction, further 0.2 equiv. of NaCN were added
to the reaction mixture which was slowly warmed to ambient temperature until the reaction started.
Nevertheless, the reaction proceeded very slowly, accompanied by darkening of the mixture and the
formation of resinous by-products. After addition of 1.3 equiv. of NaCN in portions, the conversion
of 1 reached only 25%, and the yield of 2 was only 4% (entry 10). The reaction course was
additionally controlled by GC-MS spectrometry and 19F NMR spectroscopy. In this case, except for
the starting material 1 and product 2, the following by-products were identified in the reaction
mixture: hexafluoropropene (HFP) 3, CF2=CF-C(O)F 4, dicyane 5, HCN 6, SiF4 7, SO2 8, CF2=CF-
CF2-O-CF2-CFH-CF3 9, SO2F2 10, HF 11 and CH3SO2F 12. Using diglyme (DG) or TG as a
solvent, also CH3-O-CH3 13 and CF2=CF-CF2-OCH3 14 were detected in the reaction mixture.
Based on these results possible reaction routes of 1 with NaCN in MeCN or glymes might be
suggested (Scheme 1). Obviously, the main factor that influenced the regioselectivity of the
reaction was the elimination of the fluoride anion, which competed with the elimination of
fluorosulfonate anion leading to the stabilization of the intermediate I (Scheme 1). According to the
hard soft acid base Lewis [14] and Pearson [15] theories, the fluoride anion is considered as a “hard
base“ [16], and its nucleophilicity strongly depends on its solvation (nature of solvent) and the
degree of abstraction (nature of a cation). The fluoride anion could initiate not only the destruction
of the starting material 1, but also the decomposition of the product 2 leading to the formation of
HFP 3, carbonyl fluoride 4, SO2 8 and SO2F2 10. Subsequent interaction of 10 with acetonitrile
1
19
gave probably 12, which was detected by H and F NMR spectroscopy (doublet at  2.2 ppm
3
3
with JHF = 7.1 Hz and quartet at F +50.9 with JFH = 7.1 Hz) [17]. Apart from this, the traces of
methanol present in DG and TG might interact with PFAFS 1 giving rise to allyl ether 14 and
fluorosulfonic acid 15 (Scheme 1).

Scheme 1 General scheme and possible reaction pathways of PFAFS 1 with NaCN
Traces of water in the solvent also influenced the reaction course. We postulated that HF 11, HCN
6 and carbonyl fluoride 4 were formed in the reaction mixture as a result of hydrolysis of PFACN
2. Its further condensation with PFAFS 1 and HF 11 furnished the H-containing ether 9. Na[FSO3]
16 formed during the reaction course could also be protonated producing free fluorosulfonic acid
15. The reaction of 15 with cyanide anion could be explained experimentally by the presence of
cyanogen 5 and plausibly HCN 6 in the reaction mixture (GC-MS). Super acid 15 probably induced
the polymerization of acetonitrile and the formation of dimethyl ether 13 in glymes (DG and TG) as
solvents (Scheme 1). The presence of FSO3H 15 or HF 11 in the reaction mixture could be also
confirmed by the formation of silcontetrafluoride 7 as a result of the reaction with glass. Moreover,
1
a broad signal at  12.6 ppm in H NMR also proved the presence of acidic components in the
reaction mixture. With the aim to neutralize these acids, strong and non-nucleophilic bases such as
N-ethyldiisopropylamine (Hünig’s base) or diazabicyclo[5.4.0]-undec-7-en (DBU) were applied in
catalytic amounts as well as 30% water ammonia solution as an additive. As seen from the
presented results (entries 11–12), the application of DBU and Hünig’s base increased the degree of

destruction of 1 leading to the loss of yield of 2 up to 9 – 10 %. Upon addition of NH3(aq) the
reaction mixture became very viscous and PFACN 2 was not detected even in traces (entry 13).
These results could be explained by strong tendency of cations (i-Pr)2EtNH+ and DBUH+ to the
abstraction of a fluoride anion in comparison to Na+, that led to an increase in destruction of 1 and
to a decrease in the yield of 2. The substitution of NaCN through KCN significantly increased the
reactivity of the substrate. However, it was not possible to conduct the process thermodynamically
controlled. After addition of the larger amount of PFAFS 1 to the suspension of KCN in acetonitrile
at -10 ÷ -15 °C, the temperature of the reaction mixture spontaneously raised up to 76 °C and
quantitative decomposition of the starting 1 and 2 was observed (entry 14). Another factor that
influenced the decomposition of 1 and 2 probably included the higher ability of fluoride abstraction
by K+ in comparison to Na+. On the other hand, the process via addition of PFAFS 1 at 60 – 65 °C
with pre-dried KCN was not successful and 1 was recovered in quantitative yield. Moreover,
PFACN 2 was not detected even in traces (entry 15). This phenomenon could be best explained by
the insolubility of KCN even in boiling PFAFS 1. Ineffective control of the reaction temperature in
combination with a strong “cumulative effect“ as a consequence can be associated with very low
solubility of NaCN and KCN in MeCN [18]. Therefore, it was of interest to test n-Bu4N+CN- as a
cyanide-anion source which is very well soluble in a variety of organic solvents [19]. High
solubility of this reagent, e.g. in acetonitrile (70 g/100 mL, [19]) allowed to carry out the reactions
under homogeneous conditions. Furthermore, the direct addition of 1 to a solution of n-Bu4N+CN-,
as well as reverse addition of a 70% solution of n-Bu4N+CN- to the solution of 1 were investigated.
The tendency of the tetrabutylammonium cation to abstract F- is especially great and the solubility
factor (solvation effect) should play even a more important role. Upon addition of PFAFS 1 to the
solution of tetrabutylammonium cyanide (TBACN) cooled to -20 ÷ -15 °C in MeCN or DG, a
strong exothermic reaction was observed accompanied by noticeable production of resinous by-
products. Despite a reliable temperature control and the absence of spontaneous “temperature
surges“, PFACN 2 either was not detected at all (entry 16) or was registered in only traces (entry
19
17) according to F NMR. The conversion of PFAFS 1 was 65 and 50 mol%, respectively. Better
results were obtained through addition of the solution of n-Bu4N+CN- to the acetonitrile solution of
1 in at -20 ÷ -17 °C. Despite low conversion of 1 (49 mol%) and polymerization of MeCN, the
content of 2 in the reaction mixture was 13 mol%, and the yield of product 7% (entry 18).
However, if the reaction was conducted under similar conditions, but in the less polar solvent
dichloromethane (DCM), the conversion of 1 was 100% and the content of 2 in the reaction mixture
was 80 mol% according to 19F NMR (Scheme 2).

Scheme 2 Reaction route of PFAFS 1 with n-Bu4N+CN- in dichloromethane
Due to the formation of by-products, which were difficult to separate, the isolated yield of PFACN
2 was only 22 % (entry 19, Method B). In this manner, the fluoride anion abstraction using n-
Bu4N+F- and the decrease of the polarity of the solvent positively influenced both the
regioselectivity of the process as well as the increase in yield of the target product 2. During the
experiments with n-Bu4N+CN- only pre-dried MeCN, DG, and DCM were used. Thus, the
monitoring of the reaction mixture by 19F NMR showed the absence of carbonyl fluoride 3 and allyl
ether 7 (in the case of DG). The main by-products (1, 5, 8, and 9) were also detected (Scheme 2) as
in the course of the reaction with NaCN (Scheme 1). This indicates, the reaction of PFAFS 1 with
CN- is based on general principles and do not depend on the type of the cation.
Table 1
Screening of reaction conditions of PFAFS 1 with various sources of CN-
Entry Cyanide
Additive,
Mol. ratio of
PFAFS 1 : CN-
1 : 1.98
Solvent
Time,
hrs
T, °C
Yield
(%)a
27
%
-
1
2
3
4
5
NaCN
NaCN
NaCN
NaCN
NaCN
MeCN
MeCN
TG
2.0
-10
-
1 : 1.87
18.0
2.5
-16 ÷ -10
-10 ÷ 60
-10 ÷ 24
-13
24
-
1 : 1.02
18
d
-
1 : 1.95
NMP
Hostinert-
216
2.0
-
d
-
1 : 1.02
3.0
-
6
7
NaCN
NaCN
NaCN
NaCN
NaCNb,c
NaCN
H2O, 2.4
1 : 1.95
1 : 1.02
1 : 1.1
1 : 1.95
1 : 1.3
1 : 1.8
MeCN
H2O
2.0
2.5
3.0
2.5
10.0
2.0
-15
24
< 1d
< 1d
13
-
8
-
MeCN
-5 ÷ 2
-10 ÷ 60
-10 ÷ 24
-5 ÷ 5
9
-
-
TG
11
10
11
MeCNb
DG
4
i-Pr2EtN, 3.0
Hydroquinone, 1.0
10

12
13
14
15
16
17
18
19
NaCN
NaCN
DBU, 5.0
1 : 1.02
1 : 1.98
1 : 1.02
1 : 4.0
MeCN
MeCN
MeCN
-
MeCNb
DGb
3.0
2.0
2.0
1.5
2.5
2.0
3.0
4.0
-13
9
d
30% NH3(aq), 12
-18 ÷ -14
-15 ÷ 76
60 ÷ 65
-20 ÷ -15
-15
-
d
d
d
KCN
KCNb
-
-
-
-
-
-
-
-
-
TBACN
TBACN
TBACNc
TBACNc
1 : 1.05
1 : 1.01
1 : 1.1
< 1d
MeCNb
DCMb
-20 ÷ -17
-20 ÷ -17
7
1 : 1.1
22
a) Isolated yield
b) Dried under normal conditions
c) The cyanide was added to the solution of 1 in organic solvent (Method B).
d) According to 19F NMR analysis of the reaction mixture.
2.2. Characterization
Perfluoroallyl cyanide 2 is a colorless liquid with a b.p. 27 °C/760 mmHg. PFACN 2 could be
stored under inert atmosphere at 0 °C for months, without any changes. The purity of 2 was ca.
92% according to GC-MS spectrometry and 19F NMR spectroscopy. The structure of 2 was
unequivocally elucidated using all spectroscopic methods. like 19F, 13C NMR, IR spectroscopy and
MS-spectrometry. In the 19F NMR spectrum, a typical splitting pattern for perfluorinated
compounds is observed including three magnetically non-equivalent fluorine nuclei:
CF2(A,B)=CF(C) at δF ~ -89 (A), -104 (B) and -192 (C) ppm with gemJFF = ~ 50 Hz, cisJFF = ~ 39 Hz
trans
and
J
FF
= ~ 117 Hz. A signal corresponding to allylic fluorine nuclei from CF2-group is
allyl
observed at about δF ~ -94 ppm as a doublet of doublet of doublets (ddd) with
J
= ~ 20 Hz.
FF
Signals of CF2-group were markedly downfield shifted in comparison with PFAFS 1 (δF ~ -73 ppm
19
[12]). By F NMR spectroscopy, the disappearance of the SO2F signal (δF ~ +46 ppm [12]) can
unambiguously distinguish between PFACN 2 and 1 in a mixture. In the 13C NMR spectrum of 2, a
typical set of signals of an allylic fragment at δC ~ -156 ppm (CF2=), -123 ppm (=CF-) and -105
1
2
ppm (-CF2) with JCF = ~ 240 – 290 Hz and JCF = ~ 30 – 40 Hz could be detected. The carbon
2
nucleus from the nitrile group is registered at approximately δC ~ -110 ppm with JCF = 45 Hz. In
the IR-spectrum of PFACN strong bands at ν = 2261, 1792, 1371, 1164, 1123 and 974 cm-1 could
be distinguished which are typical for vibrational absorptions of С≡N, C=C, C–C–C, C–C–CN, F–
C–F and C–F, respectively. Multiple bands in the region 2800 – 3000 cm-1 probably indicated the
presence of CH3CN traces in the product. Mass spectrometry refers to the most convenient and
unambiguous methods for verification of the target product 2. An intensive M+•-peak with m/z 157

proved the formation of PFACN 2. Signals with m/z 138 [M-F] and 131 [M-CN] showed that the
main fragmentation route of M+• is the elimination of F or CN fragment. The presence of other
fragmentation products with m/z 107 [M-CF2], 81 [C2F3], 76 [CF2CN] and 50 [CF2] also confirm
the proposed fragmentation pathway of 2.
3. Conclusions
For the first time we reported a simple and convenient method for the synthesis of
perfluoroallyl cyanide (PFACN) 2 via addition reaction of the cyanide anion to the double bond of
perfluoroallyl fluorosulfate 1, followed by the elimination of the fluorosulfate anion as a leaving
group. Various cyanide sources (NaCN, KCN, n-Bu4N+CN-), solvents (MeCN, DG, TG, water,
NMP, Hostinert-216, DCM) and reaction conditions were tested. The best results were obtained by
the addition of PFAFS to a suspension of sodium cyanide in acetonitrile or by the addition of a
solution of n-Bu4N+CN- in anhydrous DCM to PFAFS. As a result, the desired PFACN 2 was
furnished in 27% or 22% yields, respectively. The main reaction routes and factors affecting the
activity and regioselectivity of the process as well as the formation of by-products were presented.
The structure of perfluoroallyl cyanide 2 was fully established and the product 2 was for the first
time characterized by NMR, IR spectroscopy and MS spectrometry.
4. Experimental
4.1. General
All reactions were carried out in glass reaction vials under an atmosphere of dry Ar. Before use,
MeCN and DCM were freshly distilled from CaH2. DG was distilled from sodium / benzophenone
and used immediately. Unless otherwise noted, all reagents and starting materials were purchased
from commercial sources and used without further purification. PFAFS was synthesized following
a common procedure [12] with the purity of 93% (GC-MS). n-Bu4N+CN- was synthesized
according to the reported procedure [19]. All boiling points are uncorrected. 13C NMR spectra were
recorded at 100 MHz, 19F NMR spectra were recorded at 376 MHz on JEOL ECX 400 MHz
spectrometer. 13C and 19F NMR chemical shifts (δ) are reported in ppm from tetramethylsilane and
CFCl3, using the residual solvent resonance (CD3CN: δC 118.1 and 1.2 ppm) as an internal
reference. Coupling constants (J) are given in Hz. IR spectra were measured on Nicolet Magna 560
spectrometer at atmospheric pressure. GC–MS was conducted on Agilent 6890A.
4.2. Synthesis of PFACN 2

4.2.1. Method A
A 500-mL three-necked round-bottom flask, equipped with a magnetic stirrbar, reflux condenser, a
dropping funnel, thermometer, and a bubble counter was charged with NaCN (42.5 g, 0.87 mol)
suspended in MeCN (211 g, 245 mL) in the atmosphere of dry nitrogen. The suspension was cooled
to -10 °C and PFAFS 1 (100.3 g, 0.44 mol) was slowly added within 2.5 hours. At the same time, a
strong exothermic was observed and the temperature raised up to 4.4 °C. In this case the addition of
1 immediately ceased and the temperature of the reaction mixture decreased again to -10 °C. After
addition of 1, the reaction mixture was stirred for 2 hours at -10 °C and afterwards it was distilled
under reduced pressure. The following fractions were collected: fraction 1 (19.9 g, < 15 °C / 300
mmHg), fraction 2 (22.9 g, 30 °C / 300 mmHg), fraction 3 (2.5 g, > 50 °C / 293 mmHg). Then, the
fraction 1 was additionally distilled with a short Vigreux column. The fraction with b.p. 26 – 27
°C/760 mmHg was collected. 2 was obtained in 27% yield (18.6 g) as a сolorless liquid.
4.2.2. Method B
In a 100-mL three neck flask equipped with thermometer, dropping funnel and distillation set
connected to a trap cooled to -80 °C (10.5 g, 6.2 mL, 45.6 mmol) PFAFS 1 and dry DCM (24 mL)
were placed. The reaction mixture was cooled to -20 °C and the solution of TBACN (13.6 g, 50.7
mmol) in dry DCM (35 mL) was slowly added dropwise upon intense stirring (the temperature
should not exceed -17 °C). An exothermic effect was observed and the reaction mixture turned
dark. Subsequently, the cooling bath was removed. The reaction mixture was warmed to r.t. and
was mixed at this temperature for 4 hours. Afterwards, the reaction mixture was distilled using a
distillation set with a short Vigreux column. The fraction with b.p. 27 – 28 °C/760 mmHg was
collected. 1.6 g of 2 as сolorless liquid was obtained in 22% yield.
4.2.3. 2,2,3,4,4-Pentafluorobut-3-enenitrile (PFACN) (2)
13
IR (Gas phase) ν (cm-1) 2261 (С≡N), 1792 (C=C), 1371, 1164 (N≡C–C), 1123, 974; C NMR
(75.5 MHz, CD3CN) 156.2 (tdt, 1JCF = 293 Hz, 2JCF = 39 Hz, 3JCF = 4 Hz), 123.6 (dm, 1JCF = 239
Hz), 110.8 (t, 2JCF = 45 Hz), 104.5 (dddt, 1JCF = 244 Hz, 2JCF = 31 Hz, 3JCF = 6 Hz, 3JCF = 6 Hz); 19F
NMR (282.4 MHz, CD3CN):  -89.4 (ddt, 2JFF = 50 Hz, 3JFF = 39 Hz, 4JFF = 8 Hz, =CFF, 1F), -94.0
4
4
3
3
2
(ddd, JFF = 20 Hz, JFF = 8 Hz, JFF = 20 Hz, CF2, 2F), -103.8 (ddt, JFF = 117 Hz, JFF = 50 Hz,
4JFF = 20 Hz, =CFF, 1F), -192.2 (ddt, 3JFF = 117 Hz, 3JFF = 39 Hz, 4JFF = 20 Hz, =CF, 1F); GC–MS
(EI, 70 eV): m/z (%) = 157 (M+, 60), 138 (M+-F, 20), 131 (M+-CN, 88), 107 (M+-CF2, 100), 100
(C2F4, 5), 93 (CF3, 17), 81 (C2F3, 10), 76 (CF2CN, 20), 69 (CF3, 100), 50 (CF2, 8), 31 (CF, 35).

References
[1]
[2]
[3]
[4]
R. Iwa, H. Tatsu, M. Volkova, D. Rondarev, S. Sokolov, M. Greenblat, L. Senyushov, Fluorine-containing
elastomer having cyano crosslinkable groups and composition, EP Patent 708139 A1, (1996).
S. Satoru, R. Iwa, T. Haruyoshi, D. Rondarev, S. Sokolov, V. Berenblit, Process for preparation of perfluoro
unsaturated nitriles, EP Patent 710645 A1, (1996).
M.H. Hung, P.L. Tang, Fluoroelastomers having secondary cyano group cure sites, US
Patent 20150073111 A1, (2015).
C. Anolick, V. Petrov, B.E. Smart, C.W. Stewart, R.C. Wheland, W.B. Farnham, A.E. Feiring, W. Qiu,
Amorphous tetrafluoroethylene-hexafluoropropylene copolymer preparation and use for films, coatings,
additives, encapsulants, and mold release agents, US Patent 6133389, (2000).
C. Anolick, R. C. Wheland, Amorphous tetrafluoroethylene-hexafluoropropylene copolymers, US Patent
5663255, (1997).
C. Anolick, V. Petrov, B.E. Smart, C.W. Stewart, R.C. Wheland, W.B. Farnham, A.F. Feiring, W. Qiu,
Amorphous tetrafluoroethylene-hexafluoropropylene copolymers produced by a high pressure continuous
process, US Patent 5637663, (1997).
[5]
[6]
[7]
C. Anolick, V. Petrov, B.E. Smart, C.W. Stewart, R.C. Wheland, W.B. Farnham, A.F. Feiring, W. Qiu,
Manufacture of amorphous tetrafluoroethylene-hexafluoropropylene copolymers, WO Patent 9624624 A2,
(1996).
[8]
[9]
C.-Y. Hsu, P. Shen, N. Stafford, Methods for minimizing sidewall damage during low k etch processes,
US Patent 20170110336 A1, (2017).
V. Surla, R. Gupta, V. R. Pallem, Nitrogen-containing compounds for etching semiconductor structures,
US Patent 20150371869 A1, (2015).
[10] H.C. Brown, M.T. Cheng, Synthesis of perfluoroallyl-substituted 1,3,5-triazines, J. Chem. Eng. Data 13
(1968) 560–561.
[11] W.T. Miller, Pentafluoropropene derivatives, US Patent 2671799, (1954).
[12] I. Wlassics, V. Tortelli, S. Carella, C. Monzani, G. Marchionni, Perfluoro allyl fluorosulfate (FAFS): A
versatile building block for new fluoroallylic compounds, Molecules 16 (2011) 6512–6540.
[13] C. G. Krespan, D. V. England, Perfluoroallyl fluorosulfate, a reactive new perfluoroallylating agent, J. Am.
Chem. Soc. 103 (1981) 5598–5599.
[14] T.H. Lowry, K.S. Richardson, Mechanism and Theory in Organic Chemistry, Harper & Row Publishers, NY,
USA, 1981, pp. 284–285, 337, 540, 545.
[15] R.G. Pearson, Hard and soft acids and bases, Survey Prog. Chem. 5 (1969) 1–52.
[16] R.G. Parr, R.G. Pearson, Absolute hardness: companion parameter to absolute electronegativity, J. Am. Chem.
Soc. 105 (1983) 7512–7516.
[17] P. Svec, A. Eisner, L. Kolarova, T. Weidlich, V. Pejchal, A. Ruzicka, Use of C,N-chelated di-n-butyltin(IV)
fluoride for the synthesis of acyl fluorides, fluoroformates and fluorophosgene, Tetrahedron Lett. 49 (2008)
6320–6323.
[18] H. Stephen, T. Stephen, Binary Systems. Solubilities of Inorganic and Organic Compounds, Vol. 1, Part 1,
Pergamon Press Ltd., Oxford, UK, 1963, pp. 664, 694.
[19] H. Kobler, R. Munz, G. Al Gasser, G. Simchen, Eine einfache Synthese von Tetraalkylammoniumsalzen mit
funktionellen Anionen, Liebigs Ann. Chem. (1978) 1937–1945.