Synthesis and gas-separation properties of metathesis poly(3-fluoro-3-pentafluoroethyl-4,4-bis(trifluoromethyl)tricyclonene-7)

Article abstract of DOI:10.1134/S0965544115050035

Metathesis polymerization of 3-fluoro-3-pentafluoroethyl-4,4-bis(trifluoromethyl)tricyclononene-7 (F-PTCN) and the properties of the resulting polymer, particularly gas permeability, have been studied. It has been found that F-PTCN exhibits high thermal stability. The gas separation parameters of the material (P(O₂) = 60 Barrer, P(CO₂) = 240 Barrer) are close to those of fluorinated polynorbornenes studied previously. The newly synthesized fluorinated metathesis polytricyclononene has a lower gas permeability than metathesis polytricyclononene bearing two Me₃Si groups in the monomer unit, but it is significantly superior to the latter in gas separation selectivity for some gas pairs.

Full text of DOI:10.1134/S0965544115050035

ISSN 0965ꢀ5441, Petroleum Chemistry, 2015, Vol. 55, No. 9, pp. 753–758. © Pleiades Publishing, Ltd., 2015.
Original Russian Text © M.V. Bermeshev, L.E. Starannikova, S.R. Sterlin, A.A. Tyutyunov, A.N. Tavtorkin, Yu.P. Yampolskii, E.Sh. Finkelshtein, 2015, published in Membrany i Memꢀ
brannye Tekhnologii, 2015, Vol. 5, No. 3, pp. 234–240.
Synthesis and GasꢀSeparation Properties of Metathesis Poly(3ꢀ
Fluoroꢀ3ꢀPentafluoroethylꢀ4,4ꢀbis(trifluoromethyl)tricycloneneꢀ7)
a,
a
b
b
a
M. V. Bermeshev *, L. E. Starannikova , S. R. Sterlin , A. A. Tyutyunov , A. N. Tavtorkin ,
a
a
Yu. P. Yampolskii , and E. Sh. Finkelshtein
a
Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, Moscow, Russia
*
eꢀmail: bmv@ips.ac.ru
b
Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Moscow, Russia
Received December 3, 2014
Abstract—Metathesis polymerization of 3ꢀfluoroꢀ3ꢀpentafluoroethylꢀ4,4ꢀbis(trifluoromethyl)tricyclononꢀ
eneꢀ7 (FꢀPTCN) and the properties of the resulting polymer, particularly gas permeability, have been studied.
It has been found that FꢀPTCN exhibits high thermal stability. The gas separation parameters of the material
(P(O ) = 60 Barrer, P(CO ) = 240 Barrer) are close to those of fluorinated polynorbornenes studied previꢀ
2 2
ously. The newly synthesized fluorinated metathesis polytricyclononene has a lower gas permeability than
metathesis polytricyclononene bearing two Me Si groups in the monomer unit, but it is significantly superior
3
to the latter in gas separation selectivity for some gas pairs.
Keywords: tricyclononenes, metathesis polynorbornenes, fluorinated polymers, gas permeability
DOI: 10.1134/S0965544115050035
INTRODUCTION
and the gas permeability of the material has been
examined.
At present, there are a great number of highly perꢀ
meable glassy polymers and a search for new materials
for membrane technology is running on. This search is
caused by a significant increase in the membrane techꢀ
nology market and disadvantages of the existing polyꢀ
EXPERIMENTAL
The metathesis polymerization catalysts were
mer membranes whose performance characteristics Grubbs complexes (Aldrich) used without further
do not correspond to the complete set of required purification. Perfluoro(2ꢀmethylpentꢀ2ꢀene) was purꢀ
properties. The polymers that traditionally attract chased from ZAO NPO PiMꢀInvest and used as
attention as promising materials include perfluoriꢀ received. Quadricyclane was synthesized as described
nated amorphous polymers and polymers containing in [12], dried over Na, and recondensed in a vacuum.
fluorine in the pendant groups or in the backbone. The inhibitor was 2,2'ꢀmethylenebis(6ꢀtertꢀbutylꢀ4ꢀ
Perfluorinated copolymers exhibit special thermodyꢀ methylphenol) purchased from Aldrich. Toluene and
namic and transport properties, in particular fairly tetrahydrofuran (THF) were dehydrated over sodium
high selectivities in the separation of He/CH4, and stored over sodium wire under argon.
CO /CH mixtures [1–2]. There are extensive data on
2
4
NMR spectra were recorded on Bruker MSLꢀ300
the transport properties of polymers containing, for
example, CF3 or C(CF3)2 pendant groups. In the midꢀ
1
and Bruker DRX 400 NMR spectrometers. HꢀNMR
19
and FꢀNMR spectra were recorded at a frequency of
1
990s, two new metathesis polynorbornenes with Fꢀ
containing substituents were synthesized and studied
3, 4]. These polymers had fairly high gas permeability
parameters. However, these works have not been furꢀ
ther evolved despite the attractive methods developed
for the synthesis of norbornene derivatives [5–7] and
the polymerization thereof [8–11]. In this context, it
3
00.13 and 376.5 MHz, respectively. Signals were
attributed with respect to residual protons of CDCl3
[
1
(
7.24 ppm) and C D6 (7.15 ppm) in the H NMR
6
spectra and to the peak of C6F6 (–162.90 ppm) in the
FꢀNMR spectra.
19
Gas chromatography–mass spectrometry analysis
is of interest to derive new data on the effect of the was conducted on a Finnigan MAT 95 XL instrument
structure of organofluorine substituents on the gas (ionization energy, 70 eV; mass range, 20–800 amu;
separation properties of the polymers. Therefore, in resolution, 1000; source temperature, 200
this study, a new metathesis polytricyclononene has rate, 1 s/mass decade) and an HP 6890+ chromatoꢀ
been synthesized on the basis of one of the available graph equipped with a 30 m 0.25 mm capillary colꢀ
fluoroolefins—perfluoro(2ꢀmethylpentꢀ2ꢀene)— umn coated with the DBꢀ5 phase (polydimethylsiloxꢀ
°
С; scan
×
753

754
BERMESHEV et al.
ane containing 5% phenyl groups) using helium as the 2.55 m (1H), 2.43–2.22 m (1.93H), 2.17–2.09 m
2
carrier gas (at a split ratio of 1 : 30).
(0.07H), 1.39 d (1H,
J = 10.2 Hz).
Calorimetric studies were conducted on a Mettler
TAꢀ4000 differential scanning calorimeter with a
DSCꢀ30 cell at a rate of temperature increase of
+
+
Mass spectrum: 392 (2%, M ), 373 (5%, M –F),
+
+
9
2 (17%, M –С F ), 66 (100%, C H ).
6 12 5 6
2
0 deg/min in an argon atmosphere. Thermograviꢀ
metric analysis (TGA) was conducted using a Perkiꢀ
nElmer TGAꢀ7 instrument at a rate of temperature
increase of 10 deg/min.
Xꢀray diffraction measurements were conducted
on a DRONꢀ3M diffractometer in the transmission
mode (an asymmetric detectorꢀfocusing primaryꢀ
Metathesis Polymerization
A 15ꢀmL Schlenk reactor was charged with 1.0 g
of the monomer (2.55 mmol) and 8 mL of
hexafluorobenzene; after that, 0.4 mL (0.003 M, 1.2
×
–3
10
mmol) of the secondꢀgeneration Grubbs carbene
complex solution in THF was poured into the reactor
under constant stirring. The reaction mixture was
stirred at room temperature for 6 h and then admixed
to vinyl ethyl ether (0.02 mL) to deactivate the catalyst
and the 2,2'ꢀmethylenebis(6ꢀtertꢀbutylꢀ4ꢀmethylpheꢀ
nol) inhibitor (3–4 mg). The polymer was precipitated
in ethanol containing 0.5 wt % 2,2'ꢀmethylenebis(6ꢀ
tertꢀbutylꢀ4ꢀmethylphenol). The coagulated polymer
was filtered, washed with a fresh solution of 2,2'ꢀmethꢀ
ylenebis(6ꢀtertꢀbutylꢀ4ꢀmethylphenol) in ethanol and
dried in a vacuum. After that, the polymer was redisꢀ
solved in hexafluorobenzene containing the oxidation
inhibitor, reprecipitated with ethanol, and dried in a
beam quartz monochromator) using Cu
K radiation.
α
Diffraction patterns were recorded in a step scan mode
in increments of = 0.04 with an acquisition time
of = 10 s.
To examine gas permeability, films with a thickness
of 50–80 m were cast from 2–5% polymer solutions
Δ
2
θ
°
τ
µ
in C6F6. After evaporation of the solvent, the films
were evacuated to constant weight at room temperaꢀ
ture for 2 days. Gas permeability coefficients were
measured on a chromatographic setup at 22–24
and a partial pressure differential of the penetrant of
°
С
1
atm [13].
All procedures on the synthesis and polymerization
of monomers were conducted in a dry argon atmoꢀ
sphere.
vacuum at 40
repeated twice).
1H NMR (C D /C F ): 5.59–5.09 m (1H,
°
C to constant weight (the procedure was
6
6
6 6
CH=CH), 3.84–2.69 m (4H), 2.45–1.87 m (1H,
Monomer Synthesis
C(9)H ), 1.52–1.14 m (1H, C(9)H2).
2
19F NMR (
64.4–(–)66.7 (CF
), –123.2–(–)125.7 (CF
2
C
6
D
3
/C
), –77.9–(–)80.2 (CF
), –178.2–(–)
F
): –58.0–(–)60.4 (CF
),
Perfluoro(2ꢀmethylpentꢀ2ꢀene) (30 g, 0.1 mol)
and quadricyclane (14.7 g of 94% purity (6% norborꢀ
6
6
6
3
⎯
), –119–
3
nadieneꢀ2,5), 0.15 mol) were placed in a 100ꢀmL (–)121.5 (CF
2
ampoule. The mixture was frozen, evacuated, and 179.8 (CF).
then thawed with the vacuum switching valve closed.
The degassing procedure was repeated three times.
RESULTS AND DISCUSSION
The ampoule was sealed off in a vacuum and heated at
for 24 h. After that, the ampoule was open and
95 С
°
the unconverted reactants and the byꢀproduct (norꢀ
bornadieneꢀ2,5) were distilled off at atmospheric presꢀ
sure. The target monomer was distilled in a vacuum (5
Monomer Synthesis
The desired monomer was synthesized as described
mm, 78–80 С [14]). The yield was 83% (32.5 g). The in [14]. The synthesis is based on the regioꢀ and steꢀ
°
1 13
NMR spectra ( H and C) were consistent with those reospecific reaction of [
previously published [14].
of quadricyclane, which is the product of photochemꢀ
2
σ
+ 2
σ
+ 2
π
]ꢀcycloaddition
1
H NMR (CDCl ): 6.35–6.05 m (1H, CH=CH), ical isomerization of norbornadieneꢀ2,5, and perfluꢀ
3
3.38 br. s (0.07H), 3.28 br. s, 3.18 br. s (1.93H), 2.79– oro(2ꢀmethylpentꢀ2ꢀene) (Scheme 1).
F
CF3
CF3
CF3
CF3
CF3
CF3
C2F5
h
ν
C2F5
+
F
95
°
C
F
C2F
5
synꢀisomer
antiꢀisomer
synꢀ/antiꢀ = 7/93
Yield of monomer mixture 83%
Scheme 1. Synthesis of the monomer.
PETROLEUM CHEMISTRY Vol. 55
No. 9 2015

SYNTHESIS AND GASꢀSEPARATION PROPERTIES
755
(a)
(b)
Intensity, count/s
Mass, %
00
1
5
00
00
00
00
00
0
90
80
70
60
50
40
30
in argon
4
3
2
1
20
in the air
10
0
6
8
10 12 14 16 18 20 22 24
, deg
0
100 200 300 400 500 600 700 800 900 1000
, °C
2θ
T
Fig. 1. (a) Diffraction pattern and (b) TGA curves for FꢀPTCN.
Quadricyclane can react with olefins only if the latꢀ
ter comprise electron acceptor substituents. In this
case, despite the presence of strong electron acceptor
groups in perfluoro(2ꢀmethylpentꢀ2ꢀene), the reacꢀ
tion occurred only under heating, unlike some vinylꢀ
chlorosilanes [15–16]. However, it should be noted
that the singleꢀstep synthesis of fluorinated tricyꢀ
clononene is simpler than the previously developed
twoꢀstep procedure for the preparation of siliconꢀsubꢀ
stituted monomers of this kind [15–17]; in addition,
the former is based on commercially available fluoꢀ
roolefin. An increase in the time of reaction between
quadricyclane and perfluoro(2ꢀmethylpentꢀ2ꢀene)
provided the production of the target tricyclononene
with a higher yield (83% for 24 h) than in the previꢀ
CF3
CF3 RuꢀII
n
85% yield
] = 0.45 dL/g(C F )
F
[
η
6
6
C2F
5
Тg = 158 C
°
C2F
5
CF3
F CF3
FꢀPTCN
РСy3
N
N
Cl
Cl
Ru
Ru
Ph
Ph
Cl
Cl
РСу3
РСу3
ously described case (56% for 12 h [14]). After reacꢀ 1st generation Grubbs catalyst 2nd generation Grubbs catalyst
tion, the monomer was isolated as a mixture of two
isomers (synꢀ and antiꢀ); the monomer structure was
confirmed by NMR spectroscopy and mass spectromꢀ
etry.
RuꢀI
RuꢀII
Scheme 2. Metathesis polymerization of fluorinated
tricyclononene.
Metathesis Polymerization
The metathesis polymerization resulted in the
Owing to the presence of a double bond in the highꢀyield production of new fluorinated polytricyꢀ
strained norbornene moiety, the synthesized monoꢀ clononene (FꢀPTCN) exhibiting filmꢀforming propꢀ
mer was active in metathesis polymerization over both erties required for gasꢀpermeability studies. It was
firstꢀ and secondꢀgeneration Grubbs catalysts (RuꢀI found that FꢀPTCN is an amorphous polymer (Fig.
1
1
a), which has a glassꢀtransition temperature of about
60 and exhibits high thermal stability in both an
and RuꢀII, respectively; Scheme 2). However, in this
case, the activities of the catalysts were significantly
different. The use of the RuꢀII catalyst led to the forꢀ
mation of the respective polymer with considerably
°
С
inert atmosphere and the air (Fig. 1b).
Examination of the properties of FꢀPTCN revealed
higher yields (80–90% compared to 20–30% for the that this material is readily soluble in hexafluorobenꢀ
RuꢀI catalyst under the same conditions). Polymerꢀ zene, swells in
N,Nꢀdimethylformamide, acetone, and
ization was conducted in a mixture of solvents (С6F6 THF, and is insoluble in toluene, chloroform, hexane,
and THF) that provided a fairly high solubility of both and diethyl ether. The polymer forms transparent colꢀ
the polymer (С6F6) and the catalysts (THF).
orless films from solutions in hexafluorobenzene. The
PETROLEUM CHEMISTRY Vol. 55
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756
BERMESHEV et al.
Benzeneꢀd6
2.00
4.12
0.92
1.19
7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0
ppm
Fig. 2. 1H NMR spectrum of metathesis poly(3ꢀfluoroꢀ3ꢀpentafluoroethylꢀ4,4ꢀbis(trifluoromethyl)tricyclononeneꢀ7)
C D /C F ).
(
6
6
6 6
FꢀPTCN structure was confirmed by NMR spectrosꢀ pair for the new Fꢀcontaining polymer. Figure 3 shows
copy (Fig. 2).
a Robeson diagram for the He/CH4 pair. The position
of FꢀPTCN in this diagram is near the upper bond of
1
991.
An attractive combination of gas permeability and
selectivity, as well as high thermal and chemical stabilꢀ
Gas Separation Properties
The permeability of FꢀPTCN was studied for a
large set of gases (He, H , N , O , CO , CH4). The
2
2
2
2
determined gas permeability coefficients are listed in ity, makes it possible to regard FꢀPTCN as a promising
Table 1.
material for hydrocarbonꢀresistant gas separation
membranes.
It is evident that, although the synthesized polymer
is less gasꢀpermeable than metathesis polytricyꢀ
clononene comprising two Me Si groups per monoꢀ
3
CONCLUSIONS
mer unit, it exhibits permeability comparable to that of
previously studied fluorineꢀsubstituted polynorꢀ
bornenes. It is of interest to compare the selectivities
Thus, a new highꢀmolecularꢀmass fluorinated
polytricyclononene has been produced with a high
yield by metathesis polymerization in the presence of
the secondꢀgeneration Grubbs catalyst; the properties
of the product, particularly gasꢀseparation characterꢀ
istics, have been studied. It has been found that the
synthesized polymer exhibits high thermal stability
and gas separation properties comparable to those of
previously studied fluorinated metathesis polynorꢀ
bornenes. Comparison with slightly more permeable
(
ideal separation factors) of FꢀPTCN and metathesis
polytricyclononene comprising two Me Si groups per
3
monomer unit as a “hydrocarbon” polymer with a
close level of gas permeability. The ideal selectivities
are listed in Table 2. It is evident that separation factors
α
(O /N ) for the two polymers are close. Differences
2 2
take place for pairs of gases containing hydrocarbons
CH4) as a “slow” component. For example, FꢀPTCN
exhibits significantly higher gasꢀseparation selectiviꢀ
(
ties for gas pairs (CO /CH , He/CH , H /CH4) than metathesis polytricyclononene comprising two Me Si
2
4
4
2
3
those of the siliconꢀcontaining polymer (Table 2). groups per monomer unit has shown that the new
This fact is attributed to a low solubility (and thus perꢀ polymer is significantly superior to the siliconꢀconꢀ
meability) of hydrocarbons in Fꢀcontaining polymers. taining polytricyclononene in gas separation selectivꢀ
The same relationship is observed for the He/H2 gas ity for gas pairs comprising methane or hydrogen.
PETROLEUM CHEMISTRY Vol. 55
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SYNTHESIS AND GASꢀSEPARATION PROPERTIES
757
Table 1. Gas permeability coefficients for metathesis polynorbornenes
Permeability, Barrer*
Polymer
Tg, °C
Reference
This study
He
H2
O2
N2
CO2
240
CH4
20
n
1
58
69
355
230
60
20
C2F5
CF3
F CF3
n
1
–
–
166
130
50
55
17
17
200
200
13
18
[4]
[4]
CF3
CF3
F
F
n
77
O(CF ) CF3
F
2 2
F
F
n
129
227
332
89
24
396
55
[15]
Me Si
SiMe3
3
Barrer = 10–10 cm (STP) cm/cm s cmHg.
3
2
1
Table 2. Gas separation selectivity for metathesis polynorbornenes
Selectivity
α
= Pi/Pj
Polymer
Reference
This study
O /N2
CO /CH
He/H2
1.5
He/CH4 N /CH
H /CH
2
2
4
2
4
2
4
n
3.0
12.0
17.8
1.0
11.5
C2F5
CF3
CF3
F
n
2
.9
.2
15.4
11.1
–
–
–
–
1.3
0.9
12.8
7.2
[4]
[4]
CF3
CF3
F
F
n
3
F
2 2
O(CF ) CF3
F F
n
3.7
7.2
0.7
4.1
0.4
6.0
[15]
Me Si
SiMe3
3
PETROLEUM CHEMISTRY Vol. 55
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758
BERMESHEV et al.
log(
α
(He/CH ))
4
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
1991
2008
–0.5
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
log(P(He))
Fig. 3. Robeson diagram [18, 19] for the He/CH pair (green triangle, FꢀPTCN; black square, siliconꢀcontaining polytricyꢀ
4
clononene).
ACKNOWLEDGMENTS
9. S. T. Nguyen, and T. M. Trnka, Handbook of Metathesis,
Ed. by R. H. Grubbs (Wiley—VCH, Weinheim, 2008),
ch. 1.6.
This work was supported by the Ministry of Educaꢀ
tion and Science of the Russian Federation, state conꢀ
tract no. 14.120.14.1103ꢀMK.
1
0. B. Bermeshev, L. Bulgakov, G. Starannikova, et al., J.
Appl. Polym. Sci. 132, 41395 (2015). DOI:
10.1002/app.41395
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PETROLEUM CHEMISTRY Vol. 55
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