Aromatic monomers with pendant fluoroalkylsulfonate and sulfonimide groups

Article abstract of DOI:10.1016/S0022-1139(00)00308-0

Novel styrene and dimethylisophthalate monomers with pendant lithium fluoroalkylsulfonate or sulfonimide functional groups have been prepared from the corresponding phenolic intermediates. One route involves several steps and uses 1,2-dibromotetrafluoroethane as the key fluorinated intermediate. A second route with fewer steps utilizes a perfluoroalkylsulfonyl-substituted vinyl ether as the source of the fluorinated substituents but affords a product with significantly higher equivalent weight.

Full text of DOI:10.1016/S0022-1139(00)00308-0

Journal of Fluorine Chemistry 105 (2000) 129±135
Aromatic monomers with pendant ¯uoroalkylsulfonate
and sulfonimide groups
Andrew E. Feiring*, Edward R. Wonchoba
DuPont Central Research & Development, Experimental Station, P.O. Box 80328, Wilmington, DE 19880-0328, USA
Accepted 8 May 2000
Abstract
Novel styrene and dimethylisophthalate monomers with pendant lithium ¯uoroalkylsulfonate or sulfonimide functional groups have been
prepared from the corresponding phenolic intermediates. One route involves several steps and uses 1,2-dibromotetra¯uoroethane as the key
¯uorinated intermediate. A second route with fewer steps utilizes a per¯uoroalkylsulfonyl-substituted vinyl ether as the source of the
¯uorinated substituents but affords a product with signi®cantly higher equivalent weight. # 2000 Elsevier Science S.A. All rights reserved.
Keywords: Fluorinated ionomers; Lithium ¯uoroalkylsulfonates; Lithium ¯uoroalkylsulfonimides; Synthesis
1. Introduction
Several partially ¯uorinated polymers with pendant
¯uoroalkylsulfonate groups have been reported. The poly-
mer backbones include silicone [5] and epoxy [6,7] which
provide materials with improved processability and the
potential for different polymer architectures. However, in
these examples the linkages between the ¯uoroalkylsulfo-
nate groups and the polymer backbones are generally via
relative sensitive alkyl ether or amide [8,9] groups. We
considered that monomers in which the ¯uoroalkylsulfonate
group is attached via an ether linkage to an aromatic ring
should have improved chemical and thermal stability. Sty-
rene derivatives seemed of special interest because styrenes
can be polymerized with a wide variety of comonomers by
anionic, cationic, coordination and free radical processes
opening up the potential to generate many polymers with
novel architectures.
Polymers with pendant ¯uoroalkylsulfonate groups have
been of signi®cant scienti®c and commercial interest for
many years [1,2]. The best known examples are per¯uori-
nated polymers prepared by the radical copolymerization of
tetra¯uoroethylene with sulfonyl ¯uoride-substituted per-
¯uorovinyl ethers, such as monomer 1. The per¯uorinated
backbone provides high chemical and thermal stability
while the side chain functions as an exceptionally strong
acid in its sulfonic acid form or as a weakly coordinating
anion in its conjugate base form. Current and potential
applications include membranes for chloroalkali cells, bat-
teries and fuel cell and strong solid acid catalysts [3,4].
CF2ˆCFOCF2CFꢀCF3†OCF2CF2SO2F
1
We now describe synthesis of the novel styrene monomer
2 with a pendant ¯uoroalkoxysulfonate group and its analog
3 with the even more weakly coordinated bis-¯uoroalkyl-
sulfonimide group [10,11]. In addition, we have prepared the
isophthalate derivatives, 4 and 5, as precursors to condensa-
tion polymers, such as polyesters. The syntheses and proper-
ties of a variety of polymers from these monomers will be
reported separately.
Per¯uorinated polymers have special value in harsh envir-
onments, such as chloralkali cells, due to their high stability.
However, highly ¯uorinated polymers can be dif®cult to
process. In addition, per¯uorinated vinyl ethers, such as 1,
are costly, relatively unreactive during polymerization [2]
and can be polymerized only by a conventional free radical
mechanism with a limited range of comonomers. Modern
controlled polymerization techniques, such as living radical
or anionic polymerizations, cannot be applied to the ¯uori-
nated vinyl ethers so polymer architecture cannot be ®nely
controlled.
* Corresponding author. Fax: ‡1-302-695-9799.
0022-1139/00/$ ± see front matter # 2000 Elsevier Science S.A. All rights reserved.
PII: S 0 0 2 2 - 1 1 3 9 ( 0 0 ) 0 0 3 0 8 - 0

130
A.E. Feiring, E.R. Wonchoba / Journal of Fluorine Chemistry 105 (2000) 129±135
Scheme 1. Synthesis of lithium sulfonate monomer 2.
2. Results and discussion
concentrated and the resulting solid was dried for several
days at 458C and 0.05 mm. Recrystallization from boiling
benzene afforded white crystals in excellent yield. Elemen-
tal analysis and proton and ¯uorine NMR spectra agreed
well with the structure PhOCF2CF2SO3HÁH2O (11). On
heating, it remained a white solid up to its melting point
of 83±848C, at which point it turned dark and evolved a gas.
Thus, the very strong free acid can be isolated as a mono-
hydrate which is stable at room temperature, but decom-
poses rapidly at about 808C. Polymeric versions of this acid
will presumably show similar thermal stability.
In an initial effort to prepare a lithium ¯uoroalkylsulfo-
nylimide salt (Scheme 2), the sulfonyl chloride 9a was
reacted with tri¯uoromethanesulfonamide and triethylamine
according to a procedure for synthesis of imide salts from
per¯uoroalkylsulfonyl ¯uorides [16]. However, the expected
salt 13 is not formed; the major product from 9a is the
sul®nate 8a. A control experiment demonstrates that triethy-
lamine alone rapidly reduces 9a to 8a, indicating a major
difference in the chemistry of per¯uoroalkylsulfonyl chlor-
ides and ¯uorides. A sulfonamide could be prepared by
reacting 9a with ammonia. It seems likely that reaction of
this sulfonamide with tri¯uoromethanesulfonyl ¯uoride will
provide a ¯uoroalkylsulfonylimide salt but this process has
not yet been tried. The sulfonyl chloride 9a is readily
converted to the sulfonyl ¯uoride 12 using potassium ¯uor-
ide. Reaction of 12 with tri¯uoromethanesulfonamide and
triethylamine, followed by cation exchange, affords the
lithium sulfonimide 13 in good yield. Compound 13 is
converted to the styrene monomer 3 using the Heck reaction
as described above.
Synthesis of the styrene ¯uorosulfonate monomer 2 is
outlined in Scheme 1. Reaction [12,13] of potassium salt
of 4-bromophenol with 1,2-dibromotetra¯uoro-ethylene
affords ether 7a which is transformed in high yield to the
sul®nate 8a on reaction with sodium dithionite and sodium
bicarbonate in aqueous DMF [14]. The sul®nate reacts with
elemental chlorine in water to provide the sulfonyl chloride
9a [15]. The sulfonyl chloride is converted to the corre-
sponding lithium sulfonates 10a on reaction with lithium
hydroxide in aqueous THF. The lithium salt is soluble in
polar organic solvents which facilitate its puri®cation by
recrystallization to analytical purity. The styrene 2 is
obtained from 10a and ethylene under typical Heck reaction
conditions using ethylene in the presence of a Pd catalyst.
Monomer 2 is a crystalline solid, readily soluble in polar
organic solvents such as THF, ether and DMF.
The synthesis of 2 involves several steps but all go in good
yield using readily available and relatively inexpensive
reagents. Most of the reactions in Scheme 1 were known
[12±15] but had not been previously combined in this
fashion.
Although the various ¯uorinated lithium sulfonate salts
have generally shown good thermal stability (>2008C), it
was of interest to determine stability of the free acid, which
might be useful for other applications. The unsubstituted
sulfonate 10b was prepared by the same route beginning
with phenol. A solution of 10b in water was passed slowly
through a column containing a large excess of Dowex1 ion
exchange resin in the acid form. The aqueous solution was

A.E. Feiring, E.R. Wonchoba / Journal of Fluorine Chemistry 105 (2000) 129±135
131
Scheme 2. Synthesis of lithium sulfonimide monomer 3.
the sulfonyl ¯uoride group. After conversion of the sulfonyl
¯uoride to its lithium sulfonate form, only the vinyl ether
reacts with the nucleophile.
Although the synthesis in Scheme 4 appears more attrac-
tive than that described in Scheme 3 due to the number of
steps, choice of the preferred monomer is less obvious.
Intermediate 1 in Scheme 4 is far more costly than any of
the materials in Scheme 3 and requires several steps for its
preparation. Furthermore, the monomer 5 contains far more
¯uorine which is probably wasted and potentially trouble-
some for some applications. The molecular weights of 4 and
5 are 396 and 660, respectively, with much of the difference
being additional ¯uorocarbon groups which do not provide
value.
Scheme 3. Synthesis of lithium sulfonate monomer 4.
The isophthalate monomer 4 is prepared by a similar route
(Scheme 3) starting with the potassium salt of dimethyl
5-hydroxyisophthalate. Hydrolysis of the sulfonyl chloride
intermediate to the lithium sulfonate was accomplished
without affecting the ester groups using lithium carbonate
in methanol.
A related ¯uoroalkylsulfonate substituted isophthalate
monomer 5 was prepared as shown in Scheme 4. The
per¯uorovinyl ether monomer 1 can be converted to its
lithium sulfonate form 15 without affecting the sensitive
vinyl ether group by reaction with lithium carbonate in
methanol [17]. Reaction of 15 with dimethyl 5-hydroxyi-
sophthalate in the presence of a catalytic amount of lithium
tert-butoxide affords the diester 5 in excellent yield. Addi-
tions of phenols to vinyl ethers are well known and have
previously been accomplished on functionalized vinyl ethers
[18]. Attempted reaction of the phenol with 1, however,
results in a complex mixture presumably resulting from
reaction of the nucleophile with both the vinyl ether and
3. Experimental
3.1. Synthesis of 1-bromo-2-(4-bromophenoxy)tetrafluoro-
ethane (7a)
4-Bromophenol (Aldrich, 348.4 g, 2.01 mol) was dis-
solved in 1.95 l of 1.033 N potassium hydroxide in metha-
nol. This solution was evaporated to dryness on a rotary
evaporator and the resulting solid was dried at 1408C and
0.1 mm. The solid was mixed with 600 ml of DMSO under
nitrogen. 1,2-Dibromotetra¯uoroethane (571.6 g, 2.2 mol)
was added dropwise at 30±408C. The resulting mixture was
heated to 608C for 6 h. It was cooled to room temperature
and diluted to 3 l with ice and water. The organic layer was
separated and the aqueous solution was extracted with
2Â75 ml of methylene chloride. The methylene chloride
extracts were concentrated on a rotary evaporator and the
residue combined with the original organic layer. This
material was washed with 2Â400 ml of water, dried over
anhydrous magnesium sulfate and ®ltered. The ®ltrate was
distilled giving 641.2 g (92%) of product, bp 578C at
0.6 mm. 1H NMR (d, CDCl3) 7.1 (d, 2H), 7.5 (d, 2H);
19F NMR (d, CDCl3) 68.6 (2F), 86.6 (2F).
Scheme 4. Synthesis of lithium sulfonate monomer 5.

132
A.E. Feiring, E.R. Wonchoba / Journal of Fluorine Chemistry 105 (2000) 129±135
Anal. Calcd. for C8H4F4OBr2: C, 27.30; H, 1.15; Br,
45.41; F, 21.59. Found: C, 27.27; H, 1.16; Br, 44.85; F,
20.87.
(150 ml) was added and this solution was heated to 358C.
The heat source was removed and 237 g (0.64 mol) of 9a
was added dropwise over 45 min at a rate so that the
exotherm maintained the solution at about 558C. After
the addition was complete, the solution was held at 558C
for an additional 1.5 h. The solution was cooled to room
temperature. Its pH was adjusted to 7 by addition of about
3 ml of concentrated hydrochloric acid and the aqueous
solution was evaporated to dryness on the rotary evaporator.
The solid was slurried with ether and ®ltered. The ether
solution was treated with three volumes of hexane resulting
in deposition of a white solid. The solid was ®ltered off and
washed with hexane. The ®ltrate was evaporated and the
residue was again precipitated from ether solution by addi-
tion of hexane. The combined precipitates were recrystal-
lized from acetonitrile with cooling in the refrigerator with
the ®ltrate concentrated several times to collect additonal
fractions. The combined recrystallized product was dis-
solved in ether, ®ltered and concentrated on a rotary eva-
porator. The product was dried at 1008C and 0.1 mm giving
3.2. Synthesis of sodium 2-(4-bromophenoxy)tetrafluoro-
ethanesulfinate (8a)
Compound 7a (366.5,1.04 mol) was added under nitrogen
to a stirred mixture of 1.026 l of distilled and deoxygenated
water, 186.5 g of sodium bicarbonate, 500 ml of dimethyl-
formamide and 357.6 g of sodium dithionite. This mixture
was heated to 658C resulting in a rapid gas evolution. Gas
evolution ceased after about 1 h and the mixture was heated
to 70±758C for 3 h. It was cooled to about 108C in an ice
water-bath and 1 l of ethyl acetate was added. The mixture
was ®ltered and the solid was washed with ethyl acetate. The
combined ®ltrates were separated into aqueous and organic
layers and the organic layer was washed with 4Â50 ml of
saturated aqueous sodium chloride solution. The organic
layer was concentrated on a rotary evaporator to about 1/4 its
initial volume and ®ltered. The solid was washed with ethyl
acetate. The combined organic solutions were concentrated
to dryness on a rotary evaporator giving 362.6 g (97%) of
white solid 8a which was converted to the sulfonyl chloride
1
173.9 g (76%) of the title compound as a white solid. H
NMR (d, CD3OD) 7.2 (d, 2H), 7.6 (d, 2H); 19F NMR (d,
CD3OD) 116.9 (2F), 81.6 (2F).
Anal. Calcd. for C8H4F4BrLiSO3: C, 26.76; H, 1.12; F,
17.83; S, 8.93. Found: C, 26.57; H, 1.26; F, 18.94; S, 8.77.
1
without further puri®cation. H NMR (d, CD3OD) 7.2 (d,
2H), 7.6 (d, 2H); 19F NMR (d, CD3OD) 132.8 (2F), 81.9
(2F).
3.5. Synthesis of lithium 2-(4-ethenylphenoxy)tetrafluoro-
ethanesulfonate (2)
3.3. Synthesis of 2-(4-bromophenoxy)tetrafluoroethanesul-
fonyl chloride (9a)
A 1 l autoclave was charged with 69 g (0.19 mol) of 10a,
200 ml of acetonitrile, 0.88 g Pd(OAc)2, 2.48 g of tri-o-
tolylphosphine and 200 ml of triethylamine. The autoclave
was closed, cooled, evacuated and charged with ethylene to
110 psi. The mixture was heated with stirring to 858C for
24 h, holding the gas pressure at 120±125 psi by venting or
adding ethylene as needed. The mixture was cooled to room
temperature and vented to atmospheric pressure. The auto-
clave contents were recovered using a mixture of acetonitrile
and ether to rinse. The mixture was treated with 8.9 g of
lithium hydroxide monohydrate in 150 ml of water with
vigorous stirring and ®ltered through celite. The celite was
washed with acetonitrile and ether. The combined ®ltrates
were evaporated to dryness at 75±808C and 5 mm. The
residue was extracted with 0.5 l of ether and ®ltered. The
®ltrate was diluted with 0.5 l of hexane and the resulting
precipitate was collected, precipitated a second time from a
mixture of ether and hexane and dried at 658C and 0.05 mm
giving 20.6 g of product. An additional 12.8 g of product
was obtained by concentrating the above ether and hexane
®ltrates and reprecipitating the residue for a total yield of
33.4 g (58%) of the title product. 1H NMR (d, CD3CN) 5.27
(d, 1H), 5.80 (d, 1H), 6.78 (dd, 1H), 7.27 (d, 2H), 7.51 (d,
2H); 19F NMR (d, CD3CN) 116.6 (2F), 80.8 (2F).
Anal. Calcd. for C10H7F4LiO4S: C, 39.23; H, 2.30; F,
24.82; Li, 2.27; S, 10.47. Found: C, 38.18; H, 2.78; F, 22.23;
Li, 2.10; S, 9.55.
The sul®nate 8a was dissolved in a mixture of 600 ml of
deoxygenated water and 300 ml of 1,1,2-trichlorotri¯uor-
oethane (CFC-113) in a round bottom ¯ask equipped with a
dry-ice condenser and cooled to 5±158C. Chlorine gas
(134 g) was bubbled into this mixture over about 1 h. The
resulting yellow mixture was stirred 1 h without external
cooling. It was warmed to 208C and an additional 200 ml of
CFC-113 was added. The organic layer was separated and
the aqueous solution was extracted with 100 ml of 1,1,2-
trichlorotri¯uoroethane. The combined organic solutions
were dried over anhydrous magnesium sulfate and concen-
trated on a rotary evaporator. The residue was distilled
through a short Vigreux column giving 361.1 g (97%) of
1
product, bp 718C at 0.3 mm. H NMR (d, CDCl3) 7.1 (d,
2H), 7.6 (d, 2H); 19F NMR (d, CDCl3) 79.0 (2F), 107.9
(2F).
Anal. Calcd. for C8H4F4BrClSO3: C, 25.86; H, 1.08;
F, 20.46; S, 8.63. Found: C, 26.07; H, 1.17; F, 18.74; S,
8.59.
3.4. Synthesis of lithium 2-(4-bromophenoxy)tetrafluoro-
ethanesulfonate (10a)
Lithium hydroxide monohydrate (57.3 g, 1.365 mol) was
dissolved in 600 ml deoxygenated distilled water. THF

A.E. Feiring, E.R. Wonchoba / Journal of Fluorine Chemistry 105 (2000) 129±135
133
3.6. Synthesis of 2-(4-bromophenoxy)tetrafluoroethane-
sulfonyl fluoride (12)
(d, 2H); 19F NMR (d, CD3OD) 79.02 (3F) 80.21 (2F),
115.5 (2F).
Anal. Calcd. for C9H4BrF7LiNO5S2: C, 22.06; H, 0.82; N,
2.86; F, 27.14; S, 13.08; Br, 16.30; Li, 1.42. Found: C, 22.16;
H, 0.83; N, 2.85; F, 25.66; S, 12.57; Br, 16.14; Li, 1.34.
The sulfonyl chloride 9a (130 g, 0.35 mol) was added
dropwise to a stirred mixture of 105 g (1.8 mol) oven-dried
potassium ¯uoride and 500 ml of acetonitrile under nitrogen
at room temperature. After 24 h at room temperature, a
¯uorine NMR spectrum showed about an 80% conversion of
the sulfonyl chloride to ¯uoride. The mixture was warmed to
30±358C and then allowed to stir for 3 days at room
temperature. It was ®ltered and the solid rinsed with acet-
onitrile. The combined ®ltrates were concentrated on a
rotary evaporator at 408C and 150 mm and the residue
was distilled on a Kugelrohr at 80±858C and 5 mm into a
dry-ice cooled receiver. The liquid distillate was distilled
through a 12 ft Vigreux column giving 111.5 g (90%) of the
title product as a colorless liquid, bp 81±828C at 4.5 mm. 1H
NMR (d, CDCl3) 7.1 (d, 2H), 7.5 (d, 2H); 19F NMR (d,
CDCl3) 81.7(2F), 111.5 (2F), ‡44.2(1 F).
3.8. Synthesis of lithium N-(trifluoromethanesulfonyl)-2-
(4-ethenylphenoxy)-tetrafluoroethanesulfonamide (3)
A 1 l pressure vessel was charged under nitrogen with
73.5 g (0.15 mol) of 13, 300 ml of acetonitrile, 1.15 g
Pd(OAc)2, 3.09 g of tri-o-tolylphosphine and 120 ml of
triethylamine. The autoclave was closed, cooled, evacuated
and charged with ethylene to 100 psi. The mixture was
heated with stirring to 858C for 14 h, holding the gas
pressure at 125 psi by venting or adding ethylene as needed.
The mixture was cooled to room temperature and vented to
atmospheric pressure. The autoclave contents were recov-
ered using a mixture of acetonitrile and water to rinse. The
mixture was treated with 6.3 g of lithium hydroxide mono-
hydrate and 100 ml of water with vigorous stirring. Ether
(300 ml) was added and the mixture was ®ltered through
celite. A trace of 4-tert-butylcatechol was added to the
®ltrate which was concentrated to a solid. The residue
was dissolved in ether. A small aqueous layer was separated
and the ether was dried over anhydrous sodium sulfate. This
solution was ®ltered and concentrated to an oil on a rotary
evaporator. Methylene chloride (50 ml) was added and the
mixture was ®ltered. Hexane was added to the cloud point
and the mixture was ®ltered. The ®ltrate was concentrated
under vacuum resulting in separation of an oil. Trituration of
the oil with hexane caused crystallization. The crystals were
collected and dried giving 53.1 g (81%) of the title product.
A trace of 4-tert-butylcatechol was added to prevent poly-
Anal. Calcd. for C5H4F5BrSO3: C, 27.06; H, 1.14; F,
26.75; S, 9.03; Br, 22.5. Found: C, 27.13; H, 1.05; F, 26.88;
S, 8.94; Br, 22.35.
3.7. Synthesis of lithium N-(trifluoromethanesuIfonyl)-2-
(4-bromophenoxy) tetrafluoroethanesulfonamide (13)
Freshly sublimed tri¯uoromethanesulfonamide (15.51 g,
0.104 mol) was added to 240 ml of triethylamine which
was freshly distilled from lithium aluminum hydride. The
mixture was warmed to 408C to dissolve the solid, then
cooled to room temperature. The sulfonyl ¯uoride 12
(35.7 g, 0.101 mol) was added and solution was heated at
70±758C for 18 h. An F NMR spectrum of the solution
showed a trace of sulfonyl ¯uoride remained so the mixture
was treated with an additional 1 g of tri¯uoromethanesul-
fonamide and heated for 16 h at 70±758C. The resulting red
mixture was concentrated on the rotary evaporator. The
residue was dissolved in methylene chloride, washed three
times with water, dried over anhydrous magnesium sulfate
and concentrated on the rotary evaporator to 46.24 g of
red oil which was the triethylammonium salt of the title
product. 1H NMR (d, CDCl3) 1.32 (t, 9H), 3.20 (q, 6H), 7.13
(d, 2H), 7.5 (m, 3H (aromatic‡NH)); 19F NMR (d, CDCl3)
79.38 (3F) 81.0 (2F), 116.9 (2F). This salt was dis-
solved in 100 ml of methanol under nitrogen and treated
with 79.95 ml of 0.9908 M aqueous lithium hydroxide.
After stirring for 15 min, the solution was evaporated to
dryness at 65±758C under vacuum. The solid was dissolved
in methanol, concentrated in vacuum and dried at 0.1 mm.
The resulting solid was dissolved in 175 ml of ether and
hexane was added slowly until a red oil precipitated
leaving a colorless upper layer. The upper layer was dec-
anted and evaporated giving 30.9 g of crude title salt. The
salt was twice recrystallized from mixtures of ether and
hexane to give 29.7 g (60%) of the title product as a
1
merization. H NMR (d, acetone-d6) 5.25 (d, 1H) 5.80 (d,
1H), 6.80 (dd, 1H), 7.30 (d, 2H), 7.55 (d, 2H); 19F NMR (d,
acetone-d6) 78.78 (3F), 79.77 (2F), 115.52 (2F).
Anal. Calcd. for C11H7F7NO5S2LiÂ2.4H2O: C, 27.49; H,
2.48; N, 2.91; F, 27.67; Li, 1.44; S, 13.34. Found: C, 27.48;
H, 2.24, N, 3.03; F, 28.55; Li, 1.47; S, 15.26.
3.9. Synthesis of dimethyl 5-(1,1,2,2-tetrafluoro-2-
bromoethoxy)isophthalate
A solution of 70.5 g of 95% potassium methoxide
(0.956 mol) in 500 ml dry methanol was added to a suspen-
sion of 200.97 g (0.956 mol) dimethyl 5-hydroxyisophtha-
late in 400 ml of dry methanol cooled to 0±58C. The mixture
was allowed to warm to room temperature and decanted
from a small amount of white solid. The methanol solution
was concentrated on a rotary evaporator and the solid was
dried at 1508C and 0.1 mm to give 226.4 g. This salt was
dissolved in 600 ml of dry DMSO and heated to 658C. 1,2-
Dibromotetra¯uoroethane (259.8 g, 1 mol) was added drop-
wise resulting in an exotherm to 808C. After addition was
complete, the mixture was maintained at 75±858C for 4 h. It
1
white powder. H NMR (d, CD3OD) 7.20 (d, 2H), 7.60

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A.E. Feiring, E.R. Wonchoba / Journal of Fluorine Chemistry 105 (2000) 129±135
was cooled to room temperature and diluted to 2 l with ice
water. The aqueous solution was decanted from a viscous
gum and extracted with 200 ml methylene chloride. The
methylene chloride extract was concentrated and the residue
was combined with the viscous gum and washed with water.
The organic material was taken up in methylene chloride,
dried over anhydrous sodium sulfate and concentrated on a
rotary evaporator. The residue was distilled in a Kugelrohr
apparatus at 1408C and 0.2 mm giving 257.6 g of material
which was 93% pure by GLPC. Chromatography on silica
gel, eluting with hexane and then 1±4% ethyl acetate in
hexane gave the desired product in the ®rst fractions. The
combined fractions were concentrated on the rotary eva-
porator and the residue was distilled in a Kugelrohr at 1258C
Anal. Calcd. for C12H9ClF4O7S: C, 35.26; H, 2.22; Cl,
8.67; F, 18.59; S, 7.84. Found: C, 35.39; H, 2.05; Cl, 8.95; F,
18.29; S, 7.66.
3.11. Synthesis of 3,5-di(CO2CH3)-Ph-OCF2CF2SO3Li
(4)
To a suspension of 262 g (0.64 mol) 3,5-di(CO2CH3)-Ph-
OCF2CF2SO2Cl in 1 l of anhydrous methanol was added
52.1 g (0.71 mol) of anhydrous lithium carbonate. This
mixture was heated to 408C, then allowed to stir at room
temperature for 96 h. The solution was ®ltered and concen-
trated on the rotary evaporator. The solid was recrystallized
from 6 l acetonitrile, collecting two crops. The combined
solid was dried at 1808C and 0.1 mm to give 179.1 g (71%)
1
and 0.1 mm to give 239.6 g (62%) of the title product. H
NMR (d, CDCl3) 3.98 (s, 6H), 8.05 (m, 2H), 8.60 (m, 1H);
1
of product. H NMR (d, DMSO-d6) 3.95 (s, 6H), 7.95 (m,
19F NMR (d, CDCl3) 68.7 (2F), 86.4 (2F).
2H), 8.40 (m, 1H); 19F NMR (d, CDCl3) 80.9 (2F), 116.5
(2F).
Anal. Calcd. for C12H9F4BrO5: C, 37.04; H, 2.33; F, 19.53;
Br, 20.54. Found: C, 36.95; H, 2.08; F, 19.34; Br, 20.57.
Anal. Calcd for C12H9F4SO8Li: C, 36.38; H, 2.29; F,
19.18; S, 8.24; Li, 1.75. Found: C, 36.29; H, 2.47; F, 19.08;
S, 8.24; Li, 1.69.
3.10. Synthesis of 3,5-di(CO2CH3)-Ph-OCF2CF2SO2Cl
A 5 l round bottom ¯ask was charged with 109.2 g sodium
bicarbonate, 600 ml of deionized water, 226.4 g of sodium
dithionite and 300 ml of DMF. The mixture was heated to
658C and dimethyl 5-(1,1,2,2-tetra¯uoro-2-bromoethoxy)i-
sophthalate (316.2 g, 0.81 mol) was added over 15 min.
After addition was complete, the mixture was warmed to
80±858C for 4 h and then maintained at 508C overnight. The
mixture was cooled to room temperature and ®ltered. The
solid was washed with ethyl acetate which was added to the
®ltrate. A lower aqueous layer was extracted with 2Â100 ml
methylene chloride and 2Â100 ml ethyl acetate. All the
organic layers were combined, washed with 3Â50 ml brine,
dried over anhydrous sodium sulfate and concentrated on a
rotary evaporator. The residue was dried at 1208C and
0.1 mm to give a yellow-orange solid which was used in
the next step without further puri®cation. 1H NMR (d,
DMSO-d6) 3.95 (s, 6H), 7.97 (m, 2H), 8.40 (m, 1H); 19F
NMR (d, CDCl3) 80.9 (2F), 131.3 (2F). This solid was
dissolved in 1 l deionized water and 300 ml of CFC-113 was
added. The ¯ask was ®tted with a dry-ice condenser. Chlor-
ine gas was bubbled into the mixture until an excess was
present. A precipitate formed which was not completely
soluble in the CFC-113, so 500 ml of methylene chloride
were added. The excess chlorine was vented into a scrubber,
the organic layer was separated and the aqueous layer was
extracted with 3Â250 ml methylene chloride. The combined
organic layers were washed with 100 ml brine, dried over
anhydrous sodium sulfate, concentrated on a rotary eva-
porator and distilled using a Kugelrohr at 1508C and 0.2 mm
to give 277.3 g of faintly yellow solid. This material was
recrystallized from CFC-113 to give, in three crops, 257.4 g
(78%) of white solid. 1H NMR (d, CDCl3) 3.95 (s, 6H), 8.10
(m, 2H), 8.70 (m, 1H); 19F NMR (d, CDCl3) 79.0 (2F),
108.0 (2F).
3.12. Synthesis of 3,5-di(CO2CH3)Ph-
OCF2CFHOCF2CF(CF3)OCF2CF2SO3Li (5)
Dimethyl 5-hydroxyisophthalate (28.76 g, 0121 mol) was
dissolved in 200 ml of anhydrous DMF under argon.
Lithium tert-butoxide (0.749 g) was added and the mixture
was warmed to 408C, then cooled to room temperature.
Solid 15 (51.3 g, 0.114 mol) was added and the solution was
warmed to 408C. A slight exotherm was noted. The solution
was stirred for 2 h at 408C, then allowed to stir for 3 days at
room temperature. Hydrochloric acid (9.5 ml of 1.0 M) was
added and the solution was concentrated on a rotary eva-
porator. The residue was dried at 145±1508C and 0.05 mm
on a Kugelrohr. The dried solid was dissolved in 500 ml of
ether. Hexane was added dropwise until a gummy precipitate
formed. The mixture was ®ltered and the ®ltrate was con-
centrated and dried at 1008C and 0.1 mm giving 74.0 g of
white solid. Anal. Calcd. for C17H10F13O10SLi: C, 30.92; H,
1.53; F, 37.41; S, 4.86; Li, 1.05. Found: C, 30.77; H, 1.77; F,
38.89; S, 4.69; Li 0.99.
4. Conclusions
Two routes using readily available starting materials
have been described for the synthesis of aromatic monomers
having pendant ¯uoroalkylsulfonate groups. Products are
obtained in good yields. The pendant groups are attached
to the aromatic rings by robust ether linkages. We have
prepared a variety of free radical polymers and copolymers
from the styrene monomers 2 and 3 and novel poly-
esters from monomers 4 and 5. Details will be reported
separately.

A.E. Feiring, E.R. Wonchoba / Journal of Fluorine Chemistry 105 (2000) 129±135
135
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Grainger, Chem. Mater. 8 (1996) 1475.
Acknowledgements
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We thank Dr. Peter Morken (DuPont) for sharing his
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