Note: Descriptions are shown in the official language in which they were submitted.
0313
BACKGROUND OF THE INVENTION
Field of Invention
This invention relates to fluorinated a-carboxylic-
~-carbonyl fluorides, their preparation and the preparation
of fluorinated vinyl ether monomers therefrom.
Prior Art
Fluoromonomers containing carboxyl or carboxylic
ester groups, such as described in U.S. Patent 3,546,186,
issued December 8, 1970, have been difficult to prepare.
Such monomers are useful in preparing fluorohomopolymers
or copolymers with tetrafluoroethylene. Thus, it would be
advantageous to be able to prepare fluoromonomers easily.
Symmetrical difluoromalonic compounds of the
formula CF2Q2 where O~ may be COOH, COOalkyl or COF are
known (E.J.P. Fear et al., J. Appl. Chem., 5, 589-594
(1955); and J. Heicklen, J. Phys. Chem., 70, 618-627 (1966)).
Ryazanova et al., Zh. Vses. Khim. Obshchest, 1972, 17, No. 3,
347-8, describe compounds of the formula ROOC(CF2)nCOF where
n is 3, 4 or 6.
Fluoromonomers having the general structure
A-Y-CF2CF2O~CF-CF2OtpCF=CF2 wherein Y is -CnFmHl,
CF3
where n, m, 1 are zero or positive numbers which satisfy
the requirements of a difunctional fluorinated hydrocarbon
residue, and A is a functional group including -COOR, -SO2F
and -COF, are disclosed in German Application 2,504,622,
published August 7, 1975.
Fluoromonomers of the above general structure in
which A also includes -CN are disclosed in German Application
2,659,581, published July 13, 1977.
- 2 - ~r~
3i3
No method of preparing the above monomers is
provided in either of the above applications. The first
disclosures of a preparatlve method of which we are aware
are contained in German Application 2,635,312, published
February 17, 1977, Japanese Application J5-2,003,017, Serial
No. JA 079326, published January 11, 1977, and Japanese
Application J5 2,105,118, Serial No. JA 020144, published
September 3, 1977. Taken together, these applications
describe the reaction of perfluoroalkyl diiodides I(CF2)nI,
where n = 3-5, with fuming sulfuric acid to form a lactone;
reaction of said lactone with HFPO to form a ~-~ diacylfluo-
ride; and conversion of the diacylfluoride to esters of the
formula R2C RF-tCF2O-CFl-nCF2OCF=CF2 wherein RF is
CF3
perfluorinated alkyl of 1-10 carbon atoms and n = 1-5,
preferably 1-2.
Fluoromonomers having the general structure
CF2=CFO(CF2)n-X, where X includes -CO2R and -CN, R = H or
alkyl of 1-10 carbon atoms, and n = 2-12, preferably 2-4, are
disclosed in U.S. Patent 3,546,156 issued December 8, 1970.
Such monomers are useful in preparing fluorohomopolymers or
copolymers with tetrafluoroethylene, but have been difficult
to make from symmetrical compounds such as FOC-(CF2)n-COF.
Fluoromonomers having the formula
FSO2-CF2cF2OtcF-cF2ot-pcF=cF2 are disclosed in U.S. Patent
CF3
3,282,875, issued November 1, 1966. Preparation of -these
monomers by reaction of FSO2-CF2-COF with hexafluoropropylene
oxide (HFPO) is disclosed in U.S. Patent 3,301,893, issued
January 31, 1967.
113~3
Fluoromonomers of the ormula
CF3-CFcF2O-tcFCF2o~ncF=cF2 containing secondary
CN CF3
-CN groups are disclosed in U.S. Patent 3,852,326, issued
December 3, 1974. Such monomers are prepared by reacting
CF3CF-COF with HFPO.
CN
Conversion of fluoromonomers of formula
FSO2-CF2CF2O-tCF-CF2o~nCF=CF2 to carboxylated monomers
CF3
of formula HOOC-CF20-~CF-CF20~tnCF=CF2 is disclosed in
: CF3
Japanese Application J5 2053-814, Serial No. JA 129691,
published April 30, 1977.
Fluoropolymers having the formula
- ( CF2CF2 ~ CF2CF-~n
CF2
CF-CF
~1-3
CCF2
A
where A is an acid group which includes -COOH and -SO3H, are
disclosed in U.S. Patents 3,853,720 and 3,~53,721, issued
December 10, 1974. These patents do not disclose a method
of preparing the fluorinated vinyl ether monomers.
SUMMARY OF THE INVENTION
Accord~ng to the Present invention there is
provided a compound of the formula:
COOR CF3
CF2~ CF2_o_CF ~ COF
0313
wherein R is alkyl of 1-6 carbon atoms, and
rl is o-6.
Also provided is a process for preparin~ ROOC-CF2-COF
comprising: contacting SO3 with a c~mpound of the formula
ROOC CF2 CF2 OR
wherein R and Rl, alike or different, are alkyl of
1-6 carbon atoms.
Further provided is a proces~ for preparing
a compound of the ~ormula
COOR ~ 3
CF2 ~ CF2-0-CF ~ COF
: wherein R is alkyl of 1-6 carbon atoms, and
m is 1-6,
comprising: contacting a compound of the formula ROOC-CF2-COF
where R is as defined above with hexafluoropropylene
oxide.
Further provided are polymerizable monomers
of the formula Y CF3
CF2CF20 ~ CF-CF20 ~ CF=C~2
wherein Y is -COOR, -COOH, -COOM or -CN, R and M are defined as
above, and p is 1-5, and processes for preparing such monomers
-from compounds o~ the formula COOR CF3
CF2 ~ CF20CF ~ COF
DETAILED DESCRIPTION OF THE INVENTION
- The compounds of the invention are fluorine-contain-
ing a-carboxylic-~-carbonyl fluorides of the formula
COOR / CF3 \
~F2 t CF2-O-CF ~ COF
` 30
- 5
113~3:13
in which R is alkyl of 1-6 carbon atoms, particularly methyl
or ethyl and n is o-6, pre~erably 0.. The compound
H3COOC-CF2-C0F is most preferred.
The compounds of the invention where n is 0 are
prepared by reacting lower alkyl ~-alkoxytetrafluoropropionates
~iley U.S. 2,~88,537) with sulfur trioxide to obtain the
correspondin~ carboalkoxydifluoroacetyl fluorides according
to the equatlon
C~OR COOR
CF~-CF2-ORl SOo > CF2-COF
I~ III
The compounds of formula III are then
reacted with hexafluoropropylene oxide to obtain the
a~c~rboxylic~ carbonyl ~luorides of formula Y 1
wh~ch m ~ 1-6, according to the equation
COOR / O COOR CF3
CF2-COF ~ CF2-CF-CFS -~ CFz ~ CF2-O-CF ~ COF
~ III IV V
; ~he reaction o~ compounds of formula II with
sulfur trioxide is exothermic and provision should be
made ~or dissipating the heat of reaction. One method
ls to add the alkoxyester compound of formula II in small
portions to the S03 with cooling by reflux condenser or
external cooling means. Alternatively, the SO3 can
be added in small por~ions to the alkoxyester, but the
ormer procedure is pre~erred. The reaction can also be
carried out on a continuous basis by slowly feeding the
separate reactants into a cooled reaction zone from which
product is continuously withdrawn. Sulfur trioxide can be
3 used either in monomeric form or polymeric form. The
~3~33:~3
reaction is preferably carried out neat. However, it can
be operated also in the presence of diluents whlch
are relatlvely lnert to S03 or which couple with S03,
e.g., dioxane, chloroform, carbon tetrachloride,
~luorocarbon liquids and the like. Temperatures at which
the reaction is operable range from about -30C to about
250C and temperatures from about 0-100C are preferred.
Pressure is n~t a critical ~ariable and pressure both below
and above atmospheric pressure can be employed. The molecular
proportions in w.hich S03 and the compounds of formula II can
be brought together to carry out this reaction can be
varied widely such as ~rom about 1:20 to 20:1, preferably
about 2 to 1.
The reaction o~ a compound of formula III with
hexafluoropropylene oxide is preferably carried out in
~he presence of fluoride ion as a catalyst. This is
readily accomplished by using a suitable fluoride, e.g.,
an alkali metal fluoride such as cesium fluoride, potassium
~luoride; sil~er fluoride; ammonium fluoride; a tetra-
alkylammonium fluoride (alkyl Or 1-4 carbons) such as tetra-
methylammonium fluoride, te~raethylammonium fluoride, and
tetrabutylammonium fluoride, and sulfonium fluorldes such as
benzene sulfonium fluoride. The fluoride catalyst is usually
used in conjunction with an inert liquid diluent ~preferably
- an organic liquid) in which the selected fluoride is at least
0.001% soluble. The fluorlde catalyst may be used in amounts
rxom about 0.001 to about 1.0 molar equivalent per mole of
the compound of formula III. Suitable diluents include
ethylene glycol dimethyl ether, dieth~lene glycol dimethyl
ether, tetraethylene glycol dimethyl ether, and aprotic
,
- 7 -
~13~ 3
solvents such as acetonitrile. The reaction is somewhat
exothermic and pr~vision for dissipation of the heat of
reaction should be madeO Temperatures employed can range
from about -50C to about 200C with temperatures in the
range of about -10 to about 80C being preferred. Pressure
i~ not a critical ~ariable and pressures both below and above
atmospheric pressure are operable. Hexafluoropropylene
oxlde is a gas over much of the operable temperature range
and pressures close to atmospheric pressure are preferred.
Operable molar proportions o~ hexafluoropropylene oxide
to the compounds o~ ~ormula III can vary rrom about 1:20
to about 20:1, preferably abou~ 1 to 1.
As illustrated in the examples, more than one mol
o~ hexafluoropropylene oxlde c~n react with a compound of
~ormula III to yield compounds of formula V in which m is
greater than one. To obtain products with higher ~alues
o~ m~ higher molecular proportions o~ hexa~luoropropylene
oxide are employed and higher pressures and lower tempera-
tures are selected. To o4tain products with lower values
of m (e.g. 1 or 2) higher molecular proportions of thecompound of formula III are employed and lower pressures
and higher temperatures are selected.
Each of the compounds Or formula I is a reactive
organic compound which is at once a carboxylic ester and an
acid fluoride. Such fluorinated compounds are rare, and
understandably so because the known processes for synthesizing
dl~unctional carboxylic compounds readily yield dicarboxylic
esters às well as diacid fluorides but teach àlmost nothing
about how to obtain compounds with both a carboxylic ester
3 group and a carbonyl fluoride group in the same molecule.
313
.
In carrying out reactions with compounds of formula I care
must be taken to prevent their ready conversion to the
more ordinary corresponding dicarboxylic esters or
dicarbonyl fluorides.
Compounds of formula I are useful as intermediates
ln the preparatlon o~ new ~luorine~substituted polymerizable
ole~inic compounds containing carboxylic acid, ester or nitrite
groups. As shown in the examples, the compounds of ~ormula I
in which n = 0 can be reacted with hexaf.luoropropylene oxide
in the presence of fluoride ion catalyst to prepare the
compounds of formula I in which n is 1 to 6, e.g., the compounds
o~ formula V. In turn the compounds of formula V can be
pyrolyzed over a solid basic salt such as sodium phosphate,
sodium carbonate or potassium carbonate at moderate tempera-
tures to obtain the corresponding polymerizable monomers of
formula Vl according to the equation ~Example 7)
COOR I 3 COOR IF3
CF2 ~ cF2ocF ~mcoF ~ CF2CF20~ CF-CF2-O ~pCF-CF2
~20
V V~ (p is 1 to 5)
.
~ As illustrated in the examples, the monomers of
;~ ~ormula VI can be homopolymerized to heavy oils suitable as
lubricants and can be copolymerized with one or more comonomers
such as, for example, tetra~luoroethylene or chlorotri~luoroethylene,
to yield tough, solid polymers which are thermoplastic and capable
o~ being hot pressed or rolled into sheets and films for wrapplng
usesg as protective layers where exceptional chemical stability is
required and as ion exchange membranes in electrolysis cells.
~13~3
For polymer uses re~uiring ion-exchange capability,
such as electrolysis cell membranes, monomers of formula VI
ma~ also be polymerized in a ~orm in which the terminal
functional group is -COOM or -COOH. The metal salts (-COOM)
are produced from the esters (~COOR) by hydrolysis with alkali
metal hydroxldes, ammonium hydroxi.de or quaternary ammonium
hydroxide. The free acids (-COOH) are readily produced by
acid-catalyzed hydrolysis of the diesters in cold water.
Alternatively, monomers of ~ormula VI can be
converted as illustrated in Example 8 to polymerizable
monomers containing primary -CN groups:
COOR CF3 CN C~3
CFeCF20 t-CF-CF2O ~pCF=CF2 ~ ~H3~ CF2CF20 ~dF-CF20~pCF=CFz
VI - VII
Monomers o~ formula VII can also be homopolymerized
or3 preferably, copolymerized with one or more comonomers
~: such as, for example, tetrafluoroethylene, chlorotri~luoro-
ethylene or perfluoromethylvinylether, to yield tough,
solid polymers in the same manner as formula VI monomers
(Utility Examples A-D). Formula VII monomers, by
virtue of their primary -CN groups, are especially useful
for incorporating cure sites into elastomeric copolymer
compositions.
The polymerizable monomers of this invention
contain a tetrafluoroethylene segment -CF2CF~- between the
: terminal -COOR or -CN groups a.nd the first ether oxygen,
-e.g., carbons (1) and (2) in the structure
COOR CF3
CF2CF20 ~ CF-CF20 tCF=CF2
(1)(2) P
--10--
3~3
~he art-provides a means of preparing structures of
the formula
SO2F CF3
CF2C:?20~ CF-CF20~ CF=CF2
VIII
However, it is not known how to convert formula VIII struc-
tures to the corresponding carboxylated compounds because one
-CF2- is necessarily consumed in such conversions; thus
SO2F CF3
CF2CF20 ~ CF-CF20 ~; CF=CF2 ~ >
VIII
COOR CF3
; CF20 ~ CF-CF20 ~ CF=CF2
IX
While monomers of formula IX are useful they are
distinctly different a.nd demonstrably inferior to the
monomers of this invention in the properties they impart
to copolymers prepa.red from them. For example~ experiments
su~marized in Tables 1 and 2 show that copolymers
'O o~ monomer VI (R-~) with tetrafluoroethylene are superior
to similar copolymers o~ monomer IX (R=H) in tensile
properties a.nd in retention of these properties on e~posure
-~ to heat and high concentrations of alkali~.conditions found in
chlor-alkali electrolysis cells ~here carboxyl functional
~luorovinylether copolymers are useful as membranes.
~ 31 3
Table 1
Tensile Properties After Aging in 30~ NaOH a.t 90C
Days Tensile Strength Elongation
55~ A~ed PSi (~)
TFE/VI 2500 128
- 26 3500 54
61 3200 ~8
TFE/IX O 37oa 120
530 3
<lO --
' ~
Table 2
. .
Days to Onset o~ Film Brittleness in Alkaline Environment
Temperature CopolymerCo~olymer
Solution(C) _ TFE/VI TFE/IX
25~ XOH l110 >0.1 <0.1
25% D~IS05
~0~ NaOH115 >lO 3-7
- 30% NaOH 90 120 20
~Defined as rupture when film i~ bent 180.
Copolymers prepared ~rom formula VI and ~II monomers
may be represented by the repeating unit
- CF-CF2- ~-[~X -C
I
C~
. . ~ 2
~p
O
CF -CF -Y
2 2
-12-
:~3~)313
in Which Y ls -COOR, -COOH, -~OOM, or -CN, where R and M
are defined as above, p is 1 to 5, q is O to 1000, the X's
may all be fluorine or two fluorine and one chlorine, and
Z is -F, -RF or -OR~ where RF is perfluoroalkyl of 1-6 carbon
atoms, preferably 1-2 carbon atoms. The preferred copolymers
are prepared from two or more monomers and have average
compositions represented by the above formula where p is
1 or 2 and q is 1 to 200. Values o~ q from 1 to 9 are
preferred for carboxylated copolymers used as electrolysis
cell membranes; q of 20 to 200 is preferable in nitrile-
functional elastomers.
In the examples which follow parts are by weight
unless otherwise speci~ied.
Example 1
fOOCH3
`,~, ' CF2-COF
;~ Sulfur trioxide (40 ml) was added to a 3-neck
flask attached to a still and fitted with a dropping funnel
and thermometer. Crude CH30CF2CF2COOCH3 (100 g) was added
dropwise from the ~unnel to the magnetically stirred sulfur
~ trioxide at a rate to maintain a gentle reflux due to the
; exothermic reaction. When addition was complete, the mixture
was distilled at atmospheric pressure. Product distilling
- at 82-86C was shown by gas chromatographic analysis to
. .
contain about 69.5 ~ of H3COOC-CF2-COF (85%) and the remainder
mostly CH30S02F. This mixture was passed over sodium
fluoride pellets at about 400C/4 mm, converting the CH30S02F
to CH3~ and NaOS02F. Pure H3COOC-CF2-COF was then isolated
by distillation.
-13-
)313
Example ?
COOCH3 COOCH3 CF3
CFz-COF ~ CF2-CF-CF3 CsF ~ CF2-cF2-o-cF-coF
\o
In a 250 ml glass flask fltted with a
dry ice condenser and ports for add~tlon of gases,
liqulds and solids,was placed 20 ml tetraglyme
(tetr~ethyleneglycol dimethyl ether), 6.0 g CsF
~nd 26.3 g ~rude HacooccF2coF (containlng 3~g CH30SO2F).
Wlth the mixture kept below 15C, 29.2 g of hexafluoro-
: propylene oxide (HFPO) was slowly added. Upon
completion of the reaction~excess H3COOCCF2COF and HFPO
were remo~ed under YaeUum at 40C. The residue
wss dlstilled ~n~ crude H3COOC-CF2-CFz-O-CF(CF3)-COF
d~st~lled at 75-95 C/400 mm. Its structure was con~irmed by:
IR (llq): 1900, 1820~ .1330, 1250, 1140, 1035 cm
PMR (CCl~): 4.04 ppm (slnglet~
FMR ~C~14): ~ 21.6 (multiplet, lF), -82.4 (broad mult.,
..~
4F), -86~3 (mult., lF), ~llg.8 (mult.~ ~F),
~20 ~130 ppm (mult., lF3
.
--14--
~3~313
xample ~i
A 150 ml Carius tube was loaded with a mixture of
0.5 g each of CsF and KF (vacuum dried at 400C))
3 ml tetraglyme, 34.5 g H3COOC-CF2-COF and 60 g HFP0.
The tube was sealed and rotated overnight at
room temperature. Dis~illation of the reaction mixture
ylelded 15 g H3COOC-CF2-CF2-0-CF~CF3)-COF, b.p. 65~/100 mm.
; Anal. Calcd. ~or C7H3F~O~: C, 26.10; H, 0.94;
F, 5~.09
Found: C, 25.87; H, o.8g;
F) 53.34
.
' ~xam~le 4
COOCH3 COOCH3 CF3
CF2COF I C 2-~CF-CF3 ~ CF2 ~ CFz-O-CF ~nCOF
. O
Powdered cesium fluoride (15 g) was placed
in a 500 ml 4-necked ~lask, which was then plugged
~20 except for a conne~tion to a manifold attached to a
- vacuum pump and open-end manometer. ~Pcuum was
~pplied to the flask whlle it was heated with a
Meeker burner to thoroughly dry the cesium fluoride.
After the ~lask had coo-led~ dry nitrogen was admitted
snd then a large magnet1c stirrer. The flask was
- fitted w~th a thermometer, reevacuated, filled wlth
nltrogen and 20 ml of tetraglyme and 63 g (0.4 m) of
HaCOOCCF2COF added. The flask was then cooled to -10C,
evacuated and filled to 600 mm pressure with hexafluoro-
propene epoxide (HFP0) three times. Stirring was started
and the pressure of HFP0 was maintained autom~t~cally
-15-
~13~313
at 600 mm by a vacuum regulator. The HFP0 was absorbed
~teadily in an exothermic reaction and cooling was
~ecessary to keep the temperature between 0 and -lOaC.
The reaction was stopped after 140 g (0.84 m) o~ HFP0
had been absorbed.
The low layer (190 g) was distilled. The
products obtained are tabulated below. The ratio o~
products formed can be varied by the temperature of
reaction and mainly by the amount o~ HFP0 used.
; PRODUCTS
` 10
Emplrl^ A~IA~YSES
pO~DU~a b.p. wt. cal ~C
n ~ _ C~ e~ ~or~ula Calcd. Pd . Ca'~~d. -~d. Calcd ~A ~
6shoo 11.8 C7H~F90~ 26.10 25.87 0.9~ 0.89 53.09 53.34
210~100 14.9 C~OH3F~Os 24.61 24.65 0.62 0.74 58.39 58.49
57;0.3 31.3 C~3~Fa~0~ 23.~7 24.07 o.46 0.61 60.99 60.72
9~/0.2 42.5 Cl~H~F~07 23.43 23.78 0.37 0.4a 62.55 62.40
585/o.2 24.8 CI~H~F~oe 23.~4 23.51 0.31 0.52 63.58 63.29
6107~0;5 5.7
~ . ' ~ , .
The procedure of Example 4 was repeated
except that 182 g (1.17 m) o~ H3COOCCF2COF wa6 used,
no cooling was used ~run at 55C) and the add~tion
o~ HFP0 was stopped after 190 g had been a~sorbed.
In the d~stillatio~ 100 g of H3CO~CCF2COF was reco~ered
and the products obtained were 87.5 g (0.27 m, 23~)
o~ the product where n = 1, 40 g (o~o8 m~ 7~) o~
the product where n = 2 and 10 g (0.015 m, 1.
o~ the product where n = 3.
Ex~mple 6
COOc~3 ~0 0C~3 IC~?3
~FzCFzOCF(CF3)COF ~ CF2-CF-CF3 ~ CF2 ~ CF2-O-CF ~nCOF
3o
-16-
~ 313
Using the apparatus and general procedure
Or Example 4,the reaction of 15 g o~ CsF, 20 ml
tetraglyme, 234 g of H3COOCCF2CF20CF(CF3)COF and
~3 g HFP0 was carried out at 68C. Distillation
yielded 38 g (o.o8 m, ll~) o~ the above product
where n = 2 and 6 g (0.01 m, l~) of the product
where n = ~.
Example 7
- COOCH3 CF3 ~F3 COOCH9 CF3
.^ I I I Na3PD~
CFzCFzOCFCF20CFCOF ~ CF2::F20CFCF20CF=CF~
. .
Into the top of a ~ertically mounted quartz
tube l inch in diameter and 12 lnches long containing
90 cc of fine granules o~ sodium phosphate (predr~ed
at 40oC) stirred by a motor dri~en stainless steel
: screw in the center, the granules heated to 235-240C
; by an external split-type ~urnace, was passed 6.4 g
o~ H3COOCCF2CF20CF(CF3)CF20CF(CF3)COF along with a
slow current of nitrogen over a period of 9 minutes.
: Off-vapors from the bottom of the tube were condensed
and collected in a Dry Ice-acetone cooled trap. The
quid product was distllled to obtain 3.7 g (67%) o~
~ethyl 3-~2-(trifluoroethenoxy)-l-(trifluoromethyl)-
~rlfluoroethoxy~tetrafluoropropionate7 b.p. 98C/llO mm.
: AnPl. C~lcd. ~or C~H9Fl30~: C, ?5-6l~ H, 0~72;
~, 58.51
~ound: C, 25.47; H, 0.81;
~, 59.87.
~1~3~313
Example 8
COOCH3 CF3 lONH2 fF3
CF2CF2OCFCF2OCF=CF2 + NH3 3 CF2CF20CFCF2OCF=CF2 ~ CH30H
IONH2 Tri~luoroacetic
CF2CF2OCFCF20CF=CF anhvdride
2 pyridine
CN CF
CF2CF20CFCF20CFaCF2 + H20
8 g (0.47 mol) of ammonia was added slowly with
stirring from a weighed cylinder to 200 g (0.47 mol) of methyl
- 3-[2-(trifluoroethenoxy)-1-(triflùoromethyl)trifluoroethoxy]tetra-
fluoropropionate (Example 7) and 150 cc~ of ether contained
in a flask cooled in a Dry Ice acetone bath (ca. -80C)
and evacuated. The amide so formed was extracted at room
temperature with 1,1,2-trichlorotrifluoroethane, washed
with water and then distilled; yield 17 g. of clear liquid;
b.p. 90C at lmm. Hg.
The above amide was dehydrated to the nitrile by
a method similar to that described by Campagna et al. Tetra-
hedron Letters No. 21, 1813 (1977). 170 g (0.42 mol) of amide
was dissolved in 150 cc of tetrahydrofuran at -10C, and 80 cc
(1.0 mol) of pyridine and 70 cc (0.50 mol) of trifluoroacetic
- anhydride were added consecutively, with stirring, dropwise, maintain-
ing temperature at -10 to 0C. The mixture was allowed to warm
to Z5C, ice water was added, and the product layer was
separated with the aid o~ a small quantity o~ 1,1,2-tri-
chlorotrifluoroethane. The product was washed ~ive times with
water, then distilled. Re-distillation over P2O5 is sometimes
necessary to remove traces Or water. Yield 135.3 g; b.p.
95-102C.
18-
113~313
. UTILITY EXAMPLE A
(1) r
r I ~
. . CF2
;; FC-CF9
.~ ~ O
CF2CF2COO~I9
A ~lass tube containing 2 g of methyl
3-[2 (trifluoroethenoxy)-l-(tri~luoromethyl)tri-
~luoroethoxy~tetrafluoropropionate and 0.01 ml
- of a 6~ solution of perfluoropropionyl peroxide
ln 1,1,2-trichlorotrifluoroethane was sealed under
~- vacuum and~ rotated overnight at ro~m temperature.
RemD~al of unreacted monomer under vacuum le~t
0~5 g of oily homopolymer having a repeating unit
of the above formula.
(2) ~ CF-cF2 ~ CFZ-cF
CFz
FCCF3
o
CF2CF2GOOCH3
. . . .
~ glass tube contalning 6 g o~ methyl
3-l2-(tri~luoroethenoxy~ (t~ u~ro~ethyl)trlfluor
ethoxy]tetrafluoropropionate7 1 g ~etrafluoroethylene
and 0.01 ml of a 6~ solution of perfluoroproplonyl
peroxide in l~lJ2-trichlorotrifluoroethane ~as
sealed under vacuum at llquid nitrogen temperature
and then rotated at room temperature overnight
-19-
113~313
The mlxture became ~ery viscous. RemR~ning
tetrafluoroethylene was bled o~f and an addltional
.
5 g of tetrafluoroethylene and 0.01 ml of the
perfluoropropionyl peroxide solution was sealed
into the tubeO The tube was rotated ~or 5 hours
at room temperature and then opened. Removal o~
Yolatiles at 100C under ~acuum left o.6 g of
elastomeric copolymer of the above repeating
unit where q is greater than 1.
(3) ~ CF-CFa ~ CF8-CF~
CF~
. FCCF9
. CF2-CF2-COO~
A 20 ml Carius tube containing 6~8 g
(O.OlÇ m) of methyl 3-~2-(trifluoroethenoxy)~
(~rifluoromethyl~trifluoroethoxy ~etra~luoropropionate,
1.7 g (0.017 m) of tetrafluoroethylene, 2 ml of
lJl,2-trichloro~rifluoroethane and 0.01 ml o~ a 6
solution of perfluoropropionyl peroxide ln 1,1,~-
trichlorotrifluoroethane was se~led at liquid nitrogen
temperature, rotated at room temperature overnight
and then opened. The solid produ t was separated
by filtration and washed with ether to obtain
1.7 g o~ elastomeric copolymer.
The copolymer was pressed at 250C under 500 p3i
to yield a 3 mil film which showed strong infrared
absorption for e~ter Garbonyl at 5.5 ~. Th1s fil~
. was heated for 3 hours at 100C in a solution of
15 g ~OH ln 35 g water and 35 g dimethylsulfoxide
-20-
31~
(DMSO). Infrared examinatlon of the resulting ~ilm
, .
showed the ester carbonyl band had been replaced by
carboxylic acid absorption (broad at 2.8 ~ for -OH and
at 5.95 ~ for C-O). This con~irmed that a copolymer of the
above repeating unit where q is greater than l was obtained.
(4) COOCH3 7F3 COOCH3 CF3
CF2(CF20CF)3COF Na~P04 ~ CF2CF20(CFCF20)2C 2
;~ Using the apparatus and general procedure of
Example A(l) above,22 g of H3COOCCF2[CF20CF(CF3)]3COF was
passed slowly with nitrogen over Na3P04 at 235-240C.
~` Distilla~io~ of the collected product yielded
12 g (61%) o~ methyl 3-[2-(2-~tri~luoroethenoxy~-1-
ttri~luoromethyl]trifluoroethoxy)~l-(trifluoromethyl)-
trifluoroethoxy]te~rafluoropropionate, b.p. 71C/5.5 mm.
Anal. Calcd. for C12H3F1905: C, 24.50; H, 0.51;
~, 61.38
Found: C, 24.28; H, o.68;
~, 61.44
UTILITY EXAMPLE B
20 (l~ fOOCH3 CF3 COOH C~3
I l~NaOH > I I -
2)HCl 2
.
In a separatory funnel 15 g o~ crude
COOCCF2cF20cF(cF3)cF20cF=cF2 wa shaken with
25 ml o~ 10~ ~queous NaOH at room temperature. The
~q~eous layer was separated and acldifled with cold
c~ncentrated HCl- The lower layer which separated
~8 dlstllled from a little P2OS to obtain 10.7 g
3~J/
-21-
~13Ci 3~3
of 3-t2-(trifluoroethenoxy)-1-(tri~luoromethyl)trl-
rluoroethoxy~tetrafluoropropionic acid, b.p.
53C/0.25 mm, nD = 1.3078.
Anal. Calcd. for C~HFl30~: C, 23.54; H, 0.25; F, 60.53;.
Neut. Eq., 408.
Found: C~ 23.80; H, 0.52; F, 61.71;
~eut. Eq., 407.7.
(2~ ~ CF-CF2 ~ ~ CF2-CF
CF2
CF2CF2COOH
A glass tube containing 8.8 g of 3-[2-(tri-
fluoroethenoxy)-l-(trl~luoromethyl)trifluorO~
ethoxy]tetra~luoropropionic acid,
2.2 g tetrafluoroe~hylene, 13 ml 1J1,2-trichlorotri-
; ~uor~ethane and 0.01 ml of a 6~ solution of per-
fluoropropio"yl peroxide ln 1,1,2-trlehlorotri-
~luoroethane was sealed and rotated at room
temperature for 60 hours. ~ases were bled off
~n~ 3 g tetr~fluoroethylene and 0.01 ml of a 6~ solution
of per~luoropropionyl peroxide in 1,1,2-trichloro-
~rl~luoroethane were added. The tube was sealed,
ratAted overni~ht at room temperature and then
opened. Flltr~tion and w~shing in ether yielded
z,3 g Or copolymer o~ the repeatin~ unit indicated above
where Q is greater than 1. A pressed ~ilm showed strong
lnrrared absorption for -COOH.
-22-
3(:~313
UTILITY EXAMPLE C
3F_cF2~Crz~CF
ij CF
` ¦ .
O
~F2CF2cOoH
Using the general procedure of Example A(3), six
20 ml Carius tubes were each charged with 0.01 ml of a 6%
solution of perfluoropropionyl peroxide in 1,1,2-trichloro-
trifluaroethane and the respective quantities of methyl
3-~2-(trifluoroethenoxy)-1-(trifluoromethyl)tri~luoroethoxy]-
tetrafluoropropionate (vinyl ether), tetrafluoroethylene
(TFE) and 1~1~2-trichlorotrifIuoroethane (svlvent)
indicated in the table below. The tubes were sealed at
11quid nitrog~n temperature, rotated at room temperature
overnigh~, cooled and opened. The respec~ive amounts of
copolymer were recovered by filtration, washed with ether
and dried.
Vinyl T~ESolven~ Copolymer
Tube Ether (~) ~g)(ml)
30.4 7.2 ~ 2.45
19.5 4.6 4 2.31
: C 1~ 5 5 3.01
~ 19 5 ~ 3.55
.E 12.9 3 12 2.9
F 12.8 3 8 ~8
-23-
~13~313
The six copolymer products were combined and
a film was pressed at 360C/20,000 psi. After hydrolysis
ln KOH-H2O-DMS0 as ln Example A(4) the copolymer was shown
to have a neutral equivalent of 1500, confirming that
the copolymer had the average composition represented by
the formula above.
. .
(2) ~ F-CF2 ~ CF~-CF
F2
~CF3
- d
CF2CF2COOH
A glass tube containing 8.8 g of 3-~2-(tri-
fluoroethenoxy)-1-(trifluoromethyl)trifluoroethoxy]tetra-
fluoropropionic acid, 2.2 g tetrafluoroethylene, 13 ml
~ 2-trichlorotrifluoroethane and 0.01 ml of a 6%
solution of perfluoropropionyl pexoxide in 1~1,2-trichloro-
trifluoroethane was sealed and rotated at room temperature
ror 60 hours. Gases were bled off and 3 g tetrafluoroethylene
and 0.01 ml o~ a 6% solution of perfluoropropionyl peroxidein 1,1,2-trichlorotrifluoroethane were added. The ~ube
was sealed, rotated oYernight at room temperature and then opened.
Filtration and washing in ether yielded 2.3 g of copolymer o~ the
repeating unit indicated above where q is greater than 1. A
pressed film showed strong infrared absorption for -~OOH.
UTILITY EXAMPLE D
(1) Titration of 12.671 g (0.031 m) of 3-~2-(tri-
rluoroethenoxy)-l-(tri~luoromethyl)trifluoroethoxy]tetra-
3o
--21~--
3~3
:,
fluoropropionic acld to a neutral end point (phenolphthalein
lndicator) with 15.54 ml of 0.2N sodium hydroxide lndicated
a neutral equivalent of 407.69 (Calcd. 408). An excess o~
1 ml of 0.2N NaOH was added and the solution frozen in a 50
ml Carius tube. Then a solutlon of 0.25 g ammonium persulfate
in 10 ml water~ a solution of 0.2 g Na2S2O3 5H2O in 10 ml
water and 3.1 g tetr~fluoroethylene were added separately
with freezing before sealing the tube~ The tube was
rotated o~ernight at room temperature to obtain a clear
solution and a lit~le solid polymer. The solution was
filtered and acidified to give a gel which was mostly
soluble in ether. Removal of ether and drying at 100C
-under vacuum gave 3.2 g of copolymer from which a film was
pressed at 100~C/10,000 psi. The copolymer absor~ed
; strongl~ in the infrared for -COOH (broad 3 ~ and 5.7 ~).
(2) ~ CF-CF2 (CF2 CF2)1 ~
fF2
FfCF3
.
CF2CF2CNa
Using the general procedure of Example D(l)
a 200 ml Carius tube containing 6 g (0.015 m) o~
3-~2-(trifluoroethenoxy)-1-(trl~luoromethyl)trifluoro-
ethoxy]tetrafluoropropion~c acid neutralized with
a slight excess of 0.2N sodium hydroxide, 0.25 g ammonium
persulfate in 10 ml water, 0.02 g Na2S203-5H2O in 10 ml
water and 10 g tetra~luoroethylene was rotated overni~ht
3o
- ~3~ i3
at room temperature and then cooled and opened. A gel-
like polymer (sodium salt) was collected by filtration
and vacuum dried at 100C to gi~e 6.5 g of copolymer of
the average composition indicated by the above repeating
unit tneutral equivalent by titration 1976). The filtrate
was acidi~ied to give an acid copolymer which was
collected by ~iltration and vacuum dr~ed at 100C (wt. 5.8 g).
~ 10
