Synthesis and polymerization of novel fluoroalkyl 2-trifluoromethylacrylate possessing tetrahydrofuran moiety

Article abstract of DOI:10.1002/pola.24110

Synthesis and polymerization of novel fluoroalkyl 2-trifluoromethylacrylate [CH₂=C(CF₃)COOCH(CF₃)CF₂(C ₄H₇O)] were developed. The fluorinated alcohol was derived by hydrolysis of the product from the radical addition of 2- benzoxypentafluoropropene [CF₂=C(CF₃)OCOC ₆H₅] with tetrahydrofuran. Novel fluoroalkyl 2-trifluoromethylacrylate was synthesized by the reaction of 2trifluoromethylacryloyl chloride with the fluorinated alcohol to yield 1,1,3,3,3-pentafluoro-1 -(2-tetrahydrofuranyl)-2-propyl trifluoromethylacrylate. Radical and anionic polymerization of the monomer were examined to afford a polymer of 1.1 × 10⁴ as the highest molecular weight initiated by benzoyl peroxide at 60 °C despite low yield of the polymer although the average molecular weight of whole products was limited to about 2 × 10³.

Full text of DOI:10.1002/pola.24110

Synthesis and Polymerization of Novel Fluoroalkyl
-Trifluoromethylacrylate Possessing Tetrahydrofuran Moiety
2
1
2
1
AKIHIRO HOSOYA, HIROSHI HAMANA, TADASHI NARITA
1
Department of Applied Chemistry, Graduate School of Engineering, Saitama Institute of Technology,
1690 Fusaiji, Fukaya 369-0293, Japan
2
Department of Life Science and Green Chemistry, Saitama Institute of Technology, 1690 Fusaiji, Fukaya 369-0293, Japan
Received 25 February 2010; accepted 20 April 2010
DOI: 10.1002/pola.24110
Published online in Wiley InterScience (www.interscience.wiley.com).
KEYWORDS: anionic polymerization; fluoropolymers; radical addition; radical polymerization; 2-trifluoromethylacrylate
INTRODUCTION Radical addition of 2-benzoxypentafluoro-
propene (BPFP) with tetrahydrofuran (THF) followed by hy-
drolysis of the product yielded fluorinated alcohol as shown
2-(1,1,3,3,3-pentafluoro-2-benzoxypropyl)tetrahydrofuran was
carried out by adding 30 mmol of 2-(1,1,3,3,3-pentafluoro-2-
benzoxypropyl)tetrahydrofuran, 30 mL of methanol with 20
mL of water, and 360 mmol of sodium hydroxide under reflux-
ing for 24 h. After the reaction the product was extracted by
diethyl ether followed by washing with saturated water solu-
tion of sodium chloride and then distilled under reduced pres-
sure to afford 1,1,3,3,3-pentafluoro-1-tetrahydrofuranyl-2-pro-
1
in eq 1. 1,1,3,3,3-Pentafluoro-1-(2-tetrahydrofuranyl)-2-
propyl methacrylate [CH ¼¼ C(CH )COOCH(CF )CF (C H O)]
2
3
3
2
4 7
(
TFMA) was synthesized by the reaction of methacryloyl
chloride with fluorinated alcohol (eq 2) and radical polymer-
4
ization of TFMA afforded a polymer possessing 8.5 ꢀ 10 as
1
a number-average molecular weight. The article concerns
about the synthesis and polymerization of 2-trifluoromethy-
lacrylate derivative of fluorinated alcohol. As has been
reported ethyl 2-trifluoromethylacrylate polymer was yielded
under anionic polymerization condition and low polymeriza-
panol. 2-Trifluoromethylacryloyl chloride was synthesized by
the reaction of 2-trifluoromethylacrylic acid (1.0 mol) with
ꢁ
6,7
phthaloyl dichloride (1.0 mol) at 120 C for 2 h. The product
was collected by fractional distillation. HFIP (Central Glass Co.)
was dried by refluxing over calcium hydride and distilled.
Commercial butyllithium in a hexane solution was used after
determination of concentration by titration. 2-Trifluoromethy-
lacrylic acid supplied by Tosoh F-Tech Inc and phthaloyl
dichloride from Iharanikkei Co were used as received. BPO
was precipitated from chloroform and then recrystallized in
2
tion reactivity was demonstrated under radical conditions.
ꢁ
0
methanol at 0 C. 2,2 -Azobisisobutyronitrile (AIBN) was used
as received. LiAl(C H )(C H ) and LiZn(C H )(C H ) were
4
9
2
5 3
4
9
2 5 2
synthesized by the equimolar reactions of butyllithium with
triethylaluminum or diethylzinc, respectively, at room temper-
ature in toluene. THF and toluene were refluxed over calcium
hydride and then distilled.
EXPERIMENTAL
All experiments related to addition reactions and addition
polymerizations were carried out under a purified nitrogen
atmosphere to preclude oxygen and moisture.
Procedure
Reagents
1,1,3,3,3-Pentafluoro-1-(2-tetrahydrofuranyl)-2-propyl
tri-
BPFP was synthesized by the reaction of benzoyl chloride
with 2 eq. of lithium enolate derived from 1,1,1,3,3,3-hexa-
fluoropropan-2-ol (HFIP) with butyllithium in THF described
fluoromethylacrylate (PFTM) was synthesized by adding 42.8
mmol of 2-trifluoromethylacryloyl chloride dropwise for 1 h
to the 55 mL dichloromethane solution of 21.4 mmol of
1,1,3,3,3-pentafluoro-1-tetrahydrofuranyl-2-propanol and 43
3
,4
in the literatures. The addition reaction of BPFP with THF
was carried out by adding 123 mmol of THF and 15.4 mmol
of BPFP with 6.0 mmol of benzoyl peroxide (BPO) in glass
7
mmol of pyridine in an ice bath. The product was isolated
by extracting with diethyl ether and washed with 2 N HCl,
saturated aq. sodium hydrogencarbonate, and then saturated
sodium chloride solution, and distilled under reduced pres-
ꢁ
5
ampule under 80 C for 3 days. The product was purified
by distillation under reduced pressure to afford 2-(1,1,3,3,3-
pentafluoro-2-benzoxypropyl)tetrahydrofuran. Hydrolysis of
ꢁ
sure; bp 85.0 C/1.2 kPa; yield: 45%, purity: >97%.
Correspondence to: T. Narita (E-mail: narita@sit.ac.jp)
Journal of Polymer Science: Part A: Polymer Chemistry, Vol. 48, 3497–3500 (2010) V
2010 Wiley Periodicals, Inc.
C
NOVEL FLUOROALKYL 2-TRIFLUOROMETHYLACRYLATE, HOSOYA, HAMANA, AND NARITA
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JOURNAL OF POLYMER SCIENCE: PART A: POLYMER CHEMISTRY DOI 10.1002/POLA
TABLE 1 Polymerization of PFTM
ꢁ
a
4
a
PFTM (mmol)
Initiator
(mmol)
Solv.
Temp. ( C)
Time (day)
Yield (%)
90
M
n
(ꢀ10 )
w n
M /M
0
0
0
0
0
a
.7
.3
.7
.6
.6
BPO
BPO
AIBN
0.04
0.03
0.04
0.01
0.01
—
80
60
60
40
40
b
3
0.2
1.1
0.2
0.2
0.2
1.5
2.9
1.2
1.1
1.1
b
—
5
3
—
3
90
23
90
4
LiAl(C H
9
)(C
2
H
5
)
3
Tol
Tol
32
32
4
LiZn(C H
9
)(C
2 5 2
H )
Estimated by SEC (PSt standards, eluent THF).
Reprecipitated with hexane.
1
H NMR (CDCl ): d ¼ 1.86ꢂ2.00 ppm (4-CH , 2H, m),
diluted hydrochloric acid and water, and then freeze-dried
from benzene solution.
3
2
2
.00ꢂ2.22 (3-CH , 2H, m), 3.78ꢂ4.01 (5-CH , 2H, m), 4.09
2
2
3
3
and 4.25 (a pair of 2-CH, 1H, 2xdddd, J ¼ 5.5 and 7.8 Hz, J
1
H
NMR (CDCl3):
d
¼ 1.4ꢂ2.7 ppm (3, 4-CH2 and
3
3
¼
5.2 and 8.0 Hz, JHF ¼ 1.8 and 24.3 Hz, JHF ¼ 1.2 and
CH AC(CF ), br, 5.6H), 3.6ꢂ3.8 (5-CH , br, 2.2H), 4.0ꢂ4.3 (2-
3
2
3
2
2
2
6
4.8 Hz), 5.92 and 6.00 (a pair of CH-CF , 1H, 2xddq, JHF ¼
3
3
.8, 6.4 and 19.7 Hz, JHF ¼ 6.4, 6.4 and 16.2 Hz), 6.617 and
4
4
.624 (a pair of HC¼ cis to CF , 1H, 2xq, JHF ¼ 1.9 Hz, JHF
3
¼
1.9 Hz), 6.89 and 6.90 (a pair of HC¼ trans to CF , 1H,
4 4 13 1
3
2
xq, JHF ¼ 1.9 Hz, JHF ¼ 1.9 Hz). C NMR { H (5 ppm)}: d
3
¼
24.6 and 25.2 ppm (a pair of 3-CH , 2xd, JCF ¼ 3.8 Hz,
2
3
JCF ¼ 4.8 Hz), 25.6 and 25.8 (a pair of 4-CH ), 67.6 and
2
6
8.6 (a pair of >CF ꢂCH(CF ), m), 69.9 and 70.0 (a pair of
2
3
2
5
3
-CH
2
), 75.9 and 76.9 (a pair of 2-CH, 2xdd, JCF ¼ 24.0 and
2
4.5 Hz, JCF ¼ 23.0 and 31.7 Hz), 117.9 and 118.8 (a pair of
1
1
1
CF , 2xt, JCF ¼ 254 Hz, JCF ¼ 254 Hz), 120.8 (CF -C, q, JCF
2
3
1
¼
273 Hz), 121.3 and 121.8 (a pair of CF -CH, 2xq, JCF ¼
3
1
2
83 Hz, JCF ¼ 283 Hz), 135.3 and 135.7 (a pair of CH ¼,
2
4
4
2
>
xq, JCF ¼ 4.8 Hz, JCF ¼ 4.8 Hz), 158.4 and 158.9 (a pair of
1
9
1
C ¼¼ O). F NMR: { H (5 ppm)}: d ¼ ꢂ65.7 and ꢂ66.0 ppm
-CH,
(
a pair of CF
3
AC ¼¼ , 3F), ꢂ71.5 and ꢂ71.9 (a pair of CF
3
4
4
2
xt, JFF ¼ 12 Hz and JFF ¼ 4 Hz, 3F), ꢂ118.2, ꢂ119.6,
2
ꢂ122.6 and ꢂ124.7 (two pair of CF , 4xdq, JFF ¼ 271 Hz,
2
4
2
4
2
4
JFF ¼ 12 Hz, JFF ¼ 271 Hz, JFF ¼ 12 Hz, JFF ¼ 276 Hz, JFF
2
4
¼
4 Hz and JFF ¼ 271 Hz, JFF ¼ 12 Hz, 2F). MS: (EI, m/z):
þꢃ
7
1(100), 123(37), 283(1), (CI, m/z): 343 [MþH] , 341
þꢃ
þꢃ
[
3
MꢂH] , HRMS-CI(m/z) [MþH] . calcd for C11
43.0580, found 343.0545.
11 8 3
H F O
Polymerization was carried out by adding PFTM and initiator
into glass ampule at a determined temperature, as shown in
Table 1. Polymer produced under radical condition was sepa-
rated by washing with aq sodium hydrogencarbonate fol-
lowed by freeze-dry method in benzene. Polymer obtained
under anionic condition was separated by washing with
1
13
1
19
FIGURE 2 (a) H(5 ppm), (b) C{ H(5 ppm)}, and (c) F(–90
1
FIGURE 1 SEC of poly(PFTM) (run 2 in Table 1).
ppm){ H(5 ppm)} NMR spectra of poly(PFTM) (run 2 in Table 1).
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NOTE
SCHEME 1 Reaction profile of synthesis and polymerization.
CH, br, 0.9H), 5.4ꢂ6.1 (CF ACH(CF ), br, 1H), 7.4ꢂ8.1
The results of radical and anionic polymerizations of PFTM are
summarized in Table 1. Conversions of PFTM were quantitative
by the measurements with GC. Polymer obtained was soluble
in methanol and partly soluble in hexane, and proper reprecipi-
tation solvents were unable to be found out. Radical polymer-
2
3
1
3
1
(
C
6
H
5
ꢂ, br, 0.11H). C NMR { H (5 ppm)}: d ¼ 24.4 and
5.0 ppm (3-CH ), 25.6 (4-CH AC(CF )), 67–
), 54ꢂ60 (CH
9 (>CF ACH(CF )), 69.3ꢂ70.1 (5-CH ), 75.6 and 76.5 (2-
2
6
2
2
2
3
2
3
2
CHꢂCH ), 114.5ꢂ127.0 (CF and CF , m), 128ꢂ131
2
2
3
1
9
1
ꢁ
(
C H ꢂ), 164.5ꢂ165.5 (>C ¼¼ O). F NMR: { H (5 ppm)}: d ¼
ization initiated by BPO produces an oligomer at 80 C for 3
6
5
ꢁ
ꢂ68.4 and ꢂ71.5 ppm (CF , br, 6.1F), ꢂ119.0, ꢂ122.1 and
days. At 60 C the polymerization affords polymer possessing
3
4
ꢂ124.8 (CF , br, 2F).
1.1 ꢀ 10 as a number-average molecular weight though the
2
molecular weight distribution is rather wide as shown in Fig-
ure 1. The sample was purified by reprecipitation in a small
amount of hexane. Low molecular weight oligomers are
obtained by anionic polymerization initiated by ate complexes
Measurements
Vapor-phase chromatographic (GC) measurement was carried
out with a Hewlett-Packard 6890 equipped with flame ioni-
zation detector with a ZB-1, wide-bore capillary column (15
m ꢀ 0.53 mm, film thickness: 1.5 lm). The column tempera-
such as LiAl(C H )(C H ) and LiZn(C H )(C H ) though these
4 9 2 5 3 4 9 2 5 2
initiators have been reported to be effective for polymerization
ꢁ
ꢁ
ꢂ1
2
ture was programmed from 80 to 320 C at 20 C min
.
of 2-trifluoromethylacrylate derivatives.
Mass spectrum (MS) was measured by electron ionization
EIMS) and chemical ionization method (CIMS) on a JEOL
JMS-SX102. Isobutane was used as a reagent gas of CIMS. H,
1
13
19
H-, C- and F NMR spectra of poly(PFTM) are shown in
(
Figure 2. The assignment of each peak is designated in the figure.
The results indicate the addition polymerization takes place since
1
1
3
19
C and F NMR spectra were recorded on a JEOL JNM-
ECP500 Fourier transform NMR spectrometer at 500 MHz
no peak assignable to CH ¼¼ hydrogens are detected. Phenyl or
2
benzoxy radical may initiate the polymerization since phenyl
hydrogens are detected. The degree of polymerization calculated
from the ratio of phenyl hydrogens to methine hydrogen
assigned to f (0.11:1.0) is about 45.
1
19
for H {nondecoupled and [ F (irradiation offset: ꢂ90
1
3
1
1
ppm)]}, 125 MHz for C {[ H (5 ppm)], [ H (5 ppm) and
1
9
19
1
F (ꢂ90 ppm)]}, and 470 MHz for F[ H (5 ppm)] NMR
with deuterated chloroform as a solvent. Chemical shift of
1
9
As has been reported previously, anionic polymerization of
F NMR was determined on the basis of absolute magnetic
2
-trifluoromethylacrylates is preferable to radical polymer-
field intensity. Size exclusion chromatography (SEC) was
measured with a Tosoh HLC-802A apparatus at 40 C with
Shodex KF 802.5 and KF 801 for low molecular-weight com-
pounds and a Shodex KF 805L and Tosoh TSK gel GMHXL-L
2
ꢁ
ization. High molecular weight polymers of PFTM are
obtained by radical polymerization with BPO despite low
yields of polymers although average molecular weight of
3
polymerization products was about 2 ꢀ 10 , presumably
for high molecular-weight compounds with THF as an eluent
ꢂ1
because of the effect of the long fluorinated alkyl group as
an ester group possessing cyclic structure to protect propa-
gating radical at chain ends from termination and chain
transfer reactions.
(
flow rate: 1.0 mL min ). The molecular weight of a poly-
mer measured by SEC was calculated from the calibration
curve for polystyrene standards.
RESULTS AND DISCUSSION
Products obtained by the initiation of butyllithium, potas-
sium tert-butoxide, pyridine and triethylamine were oligom-
PFTM was synthesized by the reactions of 2-trifluoromethy-
lacryloyl chloride with fluorinated alcohol derived from the
radical addition of BPFP with THF followed by hydrolysis in
high yields. The structural determination afforded rational
results analyzed by MS and H, C, and F NMR as shown
in the ‘‘Experimental’’ section.
3
ers possessing lower molecular weight as about 2 ꢀ 10 ,
probably because of carbonyl addition.
Syntheses and polymerizations of 2-trifluoromethylacrylates
derived from 1,3-dioxolane or tetrahydropyran instead of
THF yielded similar results.
1
13
19
NOVEL FLUOROALKYL 2-TRIFLUOROMETHYLACRYLATE, HOSOYA, HAMANA, AND NARITA
3499

JOURNAL OF POLYMER SCIENCE: PART A: POLYMER CHEMISTRY DOI 10.1002/POLA
CONCLUSION
REFERENCES AND NOTES
Synthesis and polymerization of PFTM [CH ¼¼ C(CF )COOCH
1 Narita, T.; Sakuragi, Y.; Yabata, H.; Kimura, D.; Hamana, H. J
2
3
(CF
3
)CF
2
(C
4
H
7
O)] were investigated to afford a polymer of
Fluorine Chem 2007, 128, 965–970.
3
limited molecular weight of about 2 ꢀ 10 which contained
2
3
Narita, T. Prog Polym Sci 1999, 24, 1095–1148.
4
high molecular weight polymers up to 1.1 ꢀ 10 as demon-
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strated by SEC measurement after fractionation with hexane
under radical condition, as shown in Scheme 1.
4 Qian, C.-P.; Nakai, T.; Dixon, D. A.; Smart, B. E. J Am Chem
Soc 1990, 112, 4602–4604.
The authors are very much indebted to Tosoh F-Tech for provid-
ing 2-trifluoromethylacrylic acid, Central Glass for 1,1,1,3,3,3-
hexafluoropropan-2-ol, and to Iharanikkei for phthaloyl
dichloride. They are grateful for the financial support in part by
the ‘‘Open Research Center’’ Project in Saitama Institute of
Technology from the Ministry of Education, Culture, Sports, Sci-
ence and Technology of Japan, 2008ꢂ2010.
5
Narita, T.; Hagiwara, T.; Hamana, H.; Tomooka, K.; Liu, Y.-Z.;
Nakai, T. Tetrahedron Lett 1995, 36, 6091–6094.
6 Yamazaki, T.; Ichige, T.; Takei, S.; Kawashita, S.; Kitazume,
T.; Kubota, T. Org Lett 2001, 3, 2915–2918.
7
Umino, Y.; Narita, T.; Hamana, H. J Polym Sci A, Polym
Chem 2008, 46, 7011–7021.
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