Synthesis of some α-fluoroacryl esters

Article abstract of DOI:10.1134/S1070427209010224

A possibility of producing α-fluoroacrylic esters by dehydrochlorination of the products of reaction of α-fluoro-β- chloropropanoic acid or respective acyl chloride with ethylene glycol, ethylene oxide, glycidol, epichlorohydrin and glycidyl methacrylate

Full text of DOI:10.1134/S1070427209010224

ISSN 1070-4272, Russian Journal of Applied Chemistry, 2009, Vol. 82, No. 1, pp. 116−122. © Pleiades Publishing, Ltd., 2009.
Original Russian Text © A.A. Muslinkin, N.M. Kapustina, N.N. Vyrina, 2009, published in Zhurnal Prikladnoi Khimii, 2009, Vol. 82, No. 1, pp. 117−123.
MACROMOLECULAR CHEMISTRY
AND POLYMERIC MATERIALS
Synthesis of Some α-Fluoroacryl Esters
A. A. Muslinkin, N. M. Kapustina, and N. N. Vyrina
Arbuzov Institute of Organic and Physical Chemistry, Kazan Scientific Center, Russian Academy of Sciences, Kazan, Russia
Received March 13, 2008
Abstract—A possibility of producing α-fluoroacrylic esters by dehydrochlorination of the products of reaction
of α-fluoro-β-chloropropanoic acid or respective acyl chloride with ethylene glycol, ethylene oxide, glycidol,
epichlorohydrin and glycidyl methacrylate is examined.
DOI: 10.1134/S1070427209010224
In the large class of α-substituted acrylates the α-
fluoroacrylic acid derivatives are the less accessible and
insufficiently studied compounds. The data concerning
methods of synthesis and properties of the α-fluoro-
acrylates as well as of polymer materials based on these
compounds can mostly be found in the patent sources
[1]. It is known from these data that the fluoroacrylates
are highly reactive compounds in polymerization [2], and
the characteristics of the respective polymers makes the
latter very valuable for practical application: high thermal
stability, transparency, and stability against light with the
resistance to aggressive media as well [3–11]. Therefore
the synthesis and study of properties of α-fluoroacrylates
is important both in theoretical and practical aspects.
mixture the yield of compound I equals 50%, at the 3-
fold excess 65%, therewith the yield of II is 25% and
15%, respectively. At the 2-fold excess of α-fluoro-β-
chloropropanoic acid is formed predominantly compound
II in the yield up to 75% of the theoretical one.
The second and the third steps (equations 2 and 3)
were carried out separately, also in benzene medium, in
the presence of the polymerization inhibitirs, copper(I)
chloride and hydroquinone. In the IR spectra of the
Scheme 1.
HO(CH2)2OH
HO R1
FCPA
+
80°C
In this communication we present the results of
investigation of a series of α-fluoroacrylates based on
α-fluoro-β-chloropropanoic acid [12, 13] and some of
its derivatives. Formulas, physico-chemical constants,
analytical data and yields of the obtained compounds
are listed in Tables 1 and 2. Structures of the synthesized
substances are confirmed by the data of elemental
analysis, IR and 19F NMR spectra.
HO(CH2)2 O R1
_
C6H6 H2O
,
I
(1)
(2)
+ R1 O (CH2)2 O R1
,
II
Et3N
HO(CH 2)2
R1
_
O
HO(CH 2)2
R2
,
O
HCl
The ethylene glycol mono- and di-α-fluoroacrylates
(IX) and (X) are prepared [3] by esterification of glycol
with α-fluoro-β-chloropropanoic acid followed by
separate dehydrochlorination of the ethylene glycol
mono- and di-α-fluoro-β-chloropropanoates (I) and (II)
by the reaction with triethylamine along the Scheme 1.
IX
R1
O (CH2)2
O R1
O
2
Et 3N
(3)
R2
O
(CH2)2
R2 ,
_
2HCl
The first step (eq. 1) proceeds readily in boiling
benzene in the presence of p-toluenesulfonic acid as
a catalyst. With 1.5-fold excess of glycol in the reaction
X
R1 = –C(O)CHF–CH2Cl, R2 –C(O)CF=CH2.
116

SYNTHESIS OF SOME α-FLUOROACRYL ESTERS
117
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118
MUSLINKIN et al.
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SYNTHESIS OF SOME α-FLUOROACRYL ESTERS
119
products of dehydrochlorination IX and X appear the
absorption bands in the region of 1657 and 3140 cm–1 that
are asegned to the vibrations νC=C, and of α-fluoroacryloyl
fragment of the molecules.
formation of compound XI may proceed by a thermal
dehydrochlorination of III in the course of distillation as
has been observed for the case of the phospholeneglycol
α-fluoro-β-chloropropanoate [14 ].
From the 19F NMR spectra follows that chemical shifts
of fluorine nuclei in the parent α-fluoro-β-chloropropanoic
acid (121.93 ppm) and in the products of its esterification
I and II (121.94 and 121.79 ppm respectively) are
practically the same, that is, the structural changes distant
from the F atoms do not affect their chemical shifts.
Therefore the fluorine chemical shifts of compounds IX
and X are practically the same. In contrast, in going from
fluorochloropropanoates I and II to α-fluoroacrylates
IX and X chemical shifts of the fluorine nuclei differ:
they suffer a downfield shift (to 40.59 and 41.29 ppm
respectively) that reflect difference in shielding of fluorine
nuclei in the compared compounds. Compounds I, IX and
X are colorless liquids, II is crystalline substance. They
all are well soluble in ether, benzene, acetone and other
organic solvents.
The glycidyl α-fluoroacrylate (XI) was also prepared
by another scheme [15], in the reaction of glycidol with
α-fluoroacryloyl chloride [16] in ether in the presence of
triethylamine:
+ Cl
CH2CHCH 2OH
O
R2
Et3N
.
CH2CHCH 2OR 2 + Et3N HCl .
_
Ester, HCl
O
XI
The reacton with glycidol at the three-membered ring
and related reactions with other epoxy compounds are
shown in Scheme 2.
As shown in the scheme, ethylene oxide does not react
with α-fluoro-β-chloropropanoic acid in the presence of
the catalyst TiCl4, but readily reacts with the respective
acyl chloride even at 5–10°С affording ester IV, that after
dehydrochlorination under the action of triethylamine in
boiling benzene is converted into ester XII.
The rest esters (Tables 1, 2) are prepared by the reaction
of α-fluoro-β-chloropropanoic acid and (or) respective
acyl chloride with some epoxy compounds followed by
dehydrochlorination of the formed derivatives. Therewith
the reactions with glycidol were occurred at the hydroxy
group in the presence of HCl acceptor, and at the three-
membered ring in the presence of catalyst TiCl4. Thus
in the reaction of α-fluoro-β-chloropropanoyl chloride
with glycidol in equimolar amounts at the hydroxy group
in ether solution in the presence of triethylamine two
products are obtained:
Epychlorohydrin, glycidol [17] and glycidyl
methacrylate [18] react without a solvent in the presence
of TiCl4 at 50–80°С with α-fluoro-β-chloropropanoic acid
and at 5–10°С with the respective acyl chloride affording
esters of α-fluoro-β-chloropropanoic acid. In the reaction
of α-fluoro-β-chloropropanoic acid with epichlorohydrine
the same ester VI is formed that is produced by the
pair glycidol – acyl chloride. In all the cases after
dehydrochlorination respective α-fluoroacrylates were
formed.
CH CHCH OH + Cl RR11
CH22CHCH 22OH + Cl
O
Et3N
CH2CHCH 2OR1 CH2CHCH 2OR2
,
,
+
_
HCl
For the reactions with epichlorohydrin, glycidol and
glycidyl methacrylate it is important to consider the order
of the oxide ring cleavage by α-fluoro-β-chloropropanoic
acid and the respective acyl chloride. By analogy with
the reactions of epichlorohydrine with some phosphorus
halides [19] one can expect the addition of the acid group
at the β-carbon atom, that is, formation of compound with
iso structure of the propyl fragment.
O
O
III
XI
where R1 is –C(O)CHFCH2Cl, R2 is –C(O)CF=CH2.
Alongside the main product glycidyl α-fluoro-
β-chloropropanoate (III) whose yield after triple
distillation achieves 70% is formed also glycidyl α-
fluoroacrylate (XI) whose formation can be explained
by partial dehydrochlorination of III at the action of the
triethylamine in the reaction medium. The possibility of
this reaction we showed by the independent synthesis
where by reaction of III with triethylamine was prepared
glycidyl α-fluoroacrylate (XI) in high yield. Also The
The α-fluoroacrylates obtained can be polymerized in
bulk or in a solution at heating under inert atmosphere
in the presence of the initiators of radical polymerization
[20]. The polymerization leads, depending on the
structure of the initial monomers, to the transparent
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120
MUSLINKIN et al.
Scheme 2.
X=OH, Y=H
X=OH, Y=CH 2Cl
Et3N
_
XIV
(VI)
HCl
X=OH, Y=CH 2OC(O)C(CH )=CH2
Et3N
_
3
VII
XV
HCl
TiCl4
Et3N
_
X=Cl, Y=H
IV
XII
+
CH2CHY
O
R1OX
HCl
X=Cl, Y=CH2Cl
Et3N
V
XIII
XIV
_
HCl
X=Cl, Y=CH 2OH
Et3N
_
VI
HCl
X=Cl, Y=CH 2OC(O)C(CH )=CH2
Et3N
_
3
VIII
XVI
HCl
acid, 150 g (2.2 mol) of ethylene glycol and 500 ml of
anhydrous benzene was refluxed for 12 h in the presence
of 2 g of p-toluensulfonic acid in a flask equipped with a
Dean–Stark trap and reflux condenser. After completing
the reaction (collecting the maximal amount of warer) the
solvent was distilled off, and the residue was fractionated
in a vacuum. 86 g (65%) of ethylene glycol mono-α-
fluoro-β-chloropropanoate (I) was isolated as a viscous
colorless liquid; its physico-chemical characteristics are
listed in Table 1.
soft resinous or solid glassy polymer materials with
glass transition temperature from –10 to 95°С and
decomposition temperature from 230 to 400°С (according
to thermomechanical curves). The polymers obtained
are insoluble in organic solvents but swell in a different
degree in dimethylformamide, dioxane, tetrahydrofuran
and benzene. They are flammable in the flame of gas
jet but self-extinguish upon removal of the flame. An
exclusion is glycidyl α-fluoroacrylate polymer which is
not self-extinguishing.
b. To a solution of 47.5 g (0.28 mol) ethylene
glycol mono-α-fluoro-β-chloropropanoate in 250 ml of
anhydrous benzene at room temperature while stirring
was added dropwise 28 g (0.28 mol) of triethylamine
and the mixture was refluxed for 5 h in the presence
of 0.1 g of copper(I) chloride as the polymerization
inhibitor. The triethylamine hydrochloride perecipitate
formed was filtered off and from the filtrate the solvent
was distilled off and the residue was twice distilled in a
vacuum in the presence of 0.1 g of copper(I) chloride as
the polymerization inhibitor. 20.2 g (55%) of compound
IX was obtained, colorless labile liquid, its physio-
chemical characteristics are listed in Table 2.
EXPERIMENTAL
α-Fluoro-β-chloropropanoic acid of “technical”
grade was purified along the procedure described in
[12], α-fluoro-β-chloropropanoyl and α-fluoroacryloyl
chlorides were prepared and purified according to [16],
commercial ethylene oxide, epichlorohydrin, glycidol,
glycidyl methacrylate, triethylamine and benzene were
used freshly disttilled.
The 19F NMR spectra were recorded on a Teesla
BS-487 instrument at the operating frequency 80 MHz, at
room temperature, with external reference trifluoroacetic
acid and internal reference fluorobenzene.
Ethylene glycol di-α-fluoroacrylate (X). а. Ethylene
glycol di-α-fluoro-β-chloropropanoate (II) was prepared
like above from 25.3 g (0.2 mol) of α-fluoro-β-
chloropropanoic acid and 6.2 g (0.1 mol) of ethylene
glycol in 200 ml of anhydrous benzene in the presence
of 1 g of p-toluensulfonic acid. After fractionation in
a vacuum (bp128–130°С at 0.005 mm Hg) and double
crystallization from chloroform we isolated 21 g (75%) of
The IR spectra were taken on a UR-10 spectrometer
in the region from 400 to 3800 cm–1 from liquid films,
the crystalline products from suspensions in mineral
oil.
Ethlene glycol mono-α-fluoroacrylate (IX). а.Amix-
ture of 100 g (0.8 mol) of α-fluoro-β-chloropropanoic
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SYNTHESIS OF SOME α-FLUOROACRYL ESTERS
121
compound II, of white color, mp 64–66°С. Chracteristics
are listed in Table 1.
b. From compound (VI) by the reaction with
triethylamine like above was obtained β-chloro-β′-
hydroxyisopropyl α-fluoroacrylate (XIV).
b. 12 g (0.043 mol) of the prepared ethylene glycol
di-α-fluoro-β-chloropropanoate (II) and 8.7 g (0.086 mol)
of triethylamine in 150 ml of anhydrous benzene were
refluxed for 4 h in the presence of 0.05 g of copper(I)
chloride. After fractionation in a vacuum we obtained
7 g (80%) of compound X as a labile colorless liquid
(Table 2).
β-Chloroethyl α-fluoroacrylate (XII). а. To a four-
neck flask equipped with mechanical stirrer, a reflux
condenser, a dropping funnel, and a thermometer was
loaded a solution of 16.5 g (0.14 mol) of α-fluoro-β-
chloropropanoyl chloride in 50 ml of anhydrous ether.
While stirring at the temperature 6–8°С to the solution
was added dropwise a solution of 5.5 g (0.14 mol) of
ethylene oxide in 40 ml of anhydrous ether and 3–4 drops
of concentrated H2SO4. Stirring was continued for 3 h
with stepwise temperature elevating to 10–12°С. Then
the mixture was kept for 20 days in a thick-walled glass
bottle at room temperature and then it was evaporated in
a vacuum. From the residue by fractionation we obtained
15 g (75%) of β-chloroethyl α-fluoro-β-chloropropanoate
(IV) as a colorless viscous liquid.
β,β′-Dichloroisopropyl α-fluoroacrylate (XIII).
а. To a four-neck flask equiooed with mechanical
stirrer, a reflux condenser, a dropping funnel, and a
thermometer was loaded 14.5 g (0.1 mol) of α-fluoro-β-
chloropropanoyl chloride and 0.01 g of caralyst TiCl4.
At the temperature 45–55°С while stirring was added
dropwise 9.25 g (0.1 mol) of epichlorohydrin and the
reaction mixture was heated for 1.5–2 h at 95–100°С.
After cooling the reaction mixture and crystallization
from ether – cyclohexane mixture we obtained 16.5 g
(70%) of a powder-like substance V, mp 34–36°С.
b. Likewise preceding, from 14.5 g (0.077 mol)
of β-chloroethyl α-fluoro-β-chloropropanate and 7.8 g
(0.077 mol) of triethylamine in 100 ml of anhydrous
benzene after double distillation in a vacuum we obtained
7.6 g (65%) of β-chloroethyl α-fluoroacrylate (XII) as a
colorless labile liquid.
b. In a flask as described above to a solution of 4.75 g
(0.02 mol) of compound V in 50 ml of anhydrous benzene
was added initially 0.01 g of copper(I) chloride and then
a solution of 2.1 g (0.02 mol) of triethylamine in 10 ml of
anhydrous benzene. The reaction mixture was heated for
1.5–2 h at slow boiling. The triethylamine hydrochloride
precipitate dropped was filtered off and the solvent was
removed in a vacuum. From the residue by fractionation
in a vacuum was isolated 3.5 g (87%) of compound XIII
as a colorless labile liquid.
Glycidyl α-fluoro-β-chloropropanoate (III) was
synthesized by mixing of a solution of 7.4 g (0.1 mol)
of glycidol and 10.1 g (0.1 mol) of triethylamine in 75
ml of anhydrous ether with a solution of 14.5 g (0.1
mol) of α-fluoro-β-chloropropanoyl chloride in 40 ml of
anhydrous ether at the temperature about –10°С. After
stirring and filtering off the precipitate, evaporation of the
filtrate and double fractionation of the residue in a vacuum
we obtained two fractions: 1 g (ca. 5%) of compound as
a labile colorless liquid, bp 36–38°С (0.002 mm Hg) and
13.46 g (74%) of compound XI as a viscous colorless
liquid, bp 65–67°С (0.002 mm Hg).
β-Chloro-β′-hydroxyisopropyl α-fluoroacrylate
(XIV) was obtained from epichlorohydrine by analogy
with the above procedure. а. From 37.8 g (0.3 mol)
of α-fluoro-β-chloropropanoic acid heated to melting
(55–60°С), and 27.75 g (0.3 mol) of epichlorohydrine
was obtained after fractionation in a vacuum 42 g
(64%) of β-chloro-β′-hydroxyisopropyl α-fluoro-β-
chloropropanoate (VI).
Glycidyl α-fluoroacrylate (XI). To a solution of 7.4 g
(0.1 mol) of glycidol in 75 ml of anhydrous ether cooled
between –5 and –10°С was added dropwise at stirring
initially 10.2 g (ca. 0.1 mol) of anhydrous triethylamine
and then a solution of 10.8 g (0.1 mol) of α-fluoroacryloyl
chloride in 25 ml of anhydrous ether. The reaction mixture
was stirred for 2 h at room temperature. The precipitate
formed was filtered off, and the filtrate was evaporated
in a vacuum. From the residue by double fractionation
in a vacuum in the presence of copper(I) chloride we
obtained 9.5 g (65%) of compound XI as a colorless
labile liquid.
b. From 6.87 g (0.03 mol) of compound VI dissolved
in 80 ml of anhydrous benzene, and 3.5 g (0.35 mol) of
triethylamine dissolved in 20 ml of anhydrous benzene
was obtained 4.3 g (79%) of β-chloro-β’-hydroxyisopropyl
α-fluoroacrylate (XIV) as a colorless labile liquid.
β-Chloro-β′-hydroxyisopropyl α-fluoroacrylate
(XIV) from glycidol. а. From 14.5 g (0.1 mol) of
α-fluoro-β-chloropropanoyl chloride and 7.5 g (0.1 mol)
of glycidol after fractionation in a vacuum we obtained
15.5 g (70%) of β-chloro-β′-hydroxyisopropyl α-fluoro-
β-chloropropanoate (VI) as a viscous colorless liquid.
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MUSLINKIN et al.
2. Gould H., Rouge D., and Gordon E., Compt. Rend., 1960,
β-Hydroxy-β′-methacryloyloxyisopropyl α-fluoro-
vol. 250, pp. 1073–1074.
acrylate (XV). а. From 23.5 g (0.185 mol) of α-fluoro-β-
chloropropanoic acid and 26.5 g (0.185 mol) of glycidyl
methacrylate by stirring at 60–80°С for 3 h in the
presence of 0.01 of TiCl4 and 0.1 g of copper(I) chloride
followed by heating for 3 h at 100°С, after fractionation
in a vacuum we obtained 22 g (52%) of β-hydroxy-β′-
methacrylyloxyisopropyl α-fluoro-β-chloropropanoate
(VII) as a viscous colorless liquid, soluble in benzene,
acetone, dichloroethane, and other organic solvents.
3. Japan Patent 2005112850 , GO2F1/1337; CO7C69/75,
Alpha-Fluoracrylate Compound and Composition, and
Polymer Thereof.
4. CN Patent 132 4877, C08F293/00; C08F293/00,
Fluoroacrylic Ester block Polymer and Its Prpen.
5. US Patent. 6369179, C07C69/653; C08F20/22, 2-
Fluoroacrylate ester Polymers and Use Thereof as Optical
Materials.
6. WO Patent 9518785, G02B6/00; C07C69/653, 2-
Fluoroacrylate ester Polymers and Use Thereof as Optical
Materials.
7. Japan Patent 8053402, C07C255/14; C08F20/34;
C07C255/00, Cyanoethyl fluoroacrylate.
b. From 21.5 g (0.08 mol) of compound VIII and
8.01 g (0.08 mol) of triethylamine in 150 ml of anhydrous
benzene we obtained after double vacuum distillation
14.65 g (80%) of β-hydroxy-β′-methacryloyloxyisopropyl
α-fluoroacrylate XV as a colorless labile liquid.
8. Japan Patent 5201921, C07B61/00; C07C67/343,
Production of alpha-Fluoroacrylate.
9. WO Patent 9219663, C08F220/22. Fuoroacrylate
Monomers and Polymers, Processes for Preparing the Same
and Their Use.
β-Chloro-β′-methacryloyloxyisopropyl α-fluoro-
acrylate (XVI). а. From 10.5 g (0.0725 mol) of α-
fluoro-β-chloropropanoyl chloride and 10.3 g (0.0725
mol) of glycidyl methacrylate in the presence of 0.005
g of TiCl4 and 0.1 g of copper(I) chloride by stirring at
30–50°С followed by heating for 2 h at 100°С, after
fractionation we obtained 10.8 g (71%) of β-chloro-β′-
methacryloyloxyisopropyl α-fluoro-β-chloropropanoate
(VIII) as a viscous colorless liquid, soluble in benzene,
tetrahydrofuran and other organic solvents.
10. Japan Patent 3103409, C08F4/50; C08F4/42. Preparation
of Poly(alpha-fluoroacrylate ester).
11. UK Patent 949904, C07C69/653; C07C69/00, Method of
Preparing alpha-Fluoroacrylic Acid Esters.
12. Boguslavskaya, L.S., Yarovykh, K.V., and Bulovyato-
va, A.B., Zh. Org. Khim., 1969, vol. 5, no. 11,
pp. 1932–1937.
13. USSR Inventor’s Certificate 380637 (SSSR Byull. Izobr.
MKI S 07 s 67/00), Method of Preparation of Ethylene
Glycol Mono- or Di-α-fluoroacrylates.
14. Arbuzov, B.A., Muslinkin, A.A., Vizel’ A.O., et al.., Izv.
Akad. Nauk SSSR, Ser. Khim., 1973, no. 8, pp. 1828–
1832.
15. USSR Inventor’s Certificate 351836 (SSSR Byull.
Izobr. MKI S 07 s 69/62), Method of Producing
Glycidyl α-fluoroacrylate.
16. Boguslavskaya, L.S. and Morozova, T.V., Zh. Prikl. Khim.,
1992, vol. 6, no. 4, pp. 881–886.
17. USSR Inventor’s Certificate 377017 (SSSR Byull. Izobr.
MKI S 07 s 69/62), Method of Producing α-Fluoroacrylic
Acid Esters.
18. USSR Inventor’s Certificate 370200 (SSSR Byull. Izobr.
MKI S 07 s 67/00, S07 s 69/92), Method of producing
fluorine-containing methacrylic esters.
b. From 10.7 g (0.037 mol) of β-chloro-β′-meth-
acryloyloxyisopropyl α-fluoro-β-chloropropanoate
(VIII) and 3.8 g (0.35 mol) of triethylamine in 75 ml
of anhydrous benzene we obtained after double vacuum
distillation 6.7 g (71%) of colorless labile liquid, β-chloro-
β′-methacyloyloxyisopropyl α-fluoroacrylate (XVI).
CONCLUSIONS
1. At the esterification of ethylene glycol
with α-fluoro-β-chloropropanoic acid are formed both
mono- and di-α-fluoro-β-chloropropanoates that by the
reaction with triethylamine are readily transformed to the
respective α-fluoroacrylates.
2. α-Fluoro-β-chloropropanoic acid and related acyl
chloride in the presence of Lewis acid react readily with
epoxy compounds to form the products of epoxide ring
cleavage that after dehydrochlorination with triethylamine
are converted into corresponding α-fluoroacrylates.
19. Rizpolozhenskii, N.I. and Muslinkin,A.A., Izv. Akad. Nauk
SSSR, Otd. Khim. Nauk, 1961. no. 9, pp. 1600–1606.
20. USSR Inventor’s Certificate 390107 (SSSR Byull. Izobr.
MKI S 08 f 3/62). Method of Producing Fluorine-
Containing Polymers.
REFERENCES
1. Boguslavskaya, L.S., Panteleeva, I.Yu., Morozova, T.V.,
et al., Usp. Khim., 1990, vol. 59, pp. 1555–1575.
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