GB2027709A

GB2027709A - Perfluorallyl Fluorosulfate and its Sultone and Processes for their Preparation

Info

Publication number: GB2027709A
Application number: GB7927473A
Authority: GB
Original assignee: EI Du Pont de Nemours and Co
Current assignee: EIDP Inc
Priority date: 1978-08-08
Filing date: 1979-08-07
Publication date: 1980-02-27
Also published as: GB2027709B; FR2528855A1; FR2433511A1; DE2932179C2; FR2433511B1; DE2932179A1

Abstract

Perfluoroallyl fluorosulfate and its sultone are prepared by reacting hexafluoropropene with sulfur trioxide in the presence of a trivalent boron compound. The perfluoroallyl fluorosulfate product can be homopolymerized or copolymerized with various fluoroethylenes to form resins useful as ion exchange resins or acid catalysts.

Description

SPECIFICATION Perfluoroallyl Fluorosulfate and its Sultone and Processes for their Preparation Technical Field This invention relates to perfluoroallyl fluorosulfate and its sultone, to processes for their preparation, and to the use of fluoroallyl fluorosulfate and its sultone in the preparation of ion exchange resins and acid catalysts.

Background Art In U.S. Patent 2,852,554, D. C. England discloses the reaction of hexafluoropropene with freshly distilled, liquid, an hydros sulfur trioxide to obtain 2-hydroxy-1 -trifluoromethyl-l ,2,2- trifluoroethanesulfonic acid sultone (hexafluoropropene sultone) of the formula

D. C. England, M. A. Dietrich and R. V. Lindsey in "Reaction of Fluoroolefins with SO,", J. Amer.

Chem. Soc., 82, 6181 (1960) also report the reaction of hexafluoropropene (HFP) with freshly distilled sulfur trioxide (SO3) at 1 000C to give the sultone of HFP

This reference (p. 6184) also reports the reaction of hexafluoropropene with inhibited S03 at 600C to give an unidentified mixture, bp 50-650C, and a high-boiling product which presumably is a cyclic sulfonate-sulfate anhydride of the formula

M. A. Belaventsev, L. L. Mikheev, V. M. Pavlov, G. A. Sokol'skii and I. L. Knunyants, Izv. Akad.

Nauk SSSR, Ser. Khim. 1972 (1 1), 2510-16 (Russ), Eng. Trans. p 2441-2445, disclose the reaction of (CF3)2C=CF2 with SO3 at 1 50-1 8000 to give

19%, 39%, (CF3)2C=CFOSO2F 15%, and (CF3)2C=CFOSO3OSO2F 24%.

G. A. Sokol'skii, M. A. Belaventsev, and I. L. Knunyants, Izv. Akad, Nauk SSSR, Ser. Khim. 1967 (9) 2020-2024 (Russ), Eng. Trans. p 1 935-1938, describe the reaction of the sultone of HFP with NOCI.

CF3CF=CFOSO2CI+NOF Disclosure of Invention The present invention relates to the pure compounds, perfluoroallyl fluorosulfate (CF2=CF- CF2OSO2F), and its sultone

These compounds have not previously been isolated or identified from reactions of HFP and SO3.

The present invention also relates to methods for preparing perfluoroallyl fluorosulfate and its sultone by reacting hexafluoropropene (CF3-CF=0F2) with sulfur trioxide (SO3) under anhydrous conditions in the presence of about 0.1 to about 5% by weight, based on the sulfur trioxide, of a trivalent boron compound selected from the group consisting of boric oxide (B203); boron trichloride (SCI3); boron trifluoride (BF3); tri(lower alkyl) borates (B(OR)3) where the alkyl groups contain 1 to 6 carbons, for example, trimethyl borate and triethyl borate; boron trioxychloride ((BOCI)3); and boron trioxyfluoride ((BOF)3) at a temperature of about 0 to about 1 500C for a time sufficient to produce perfluoroallyl fluorosulfate. The preferred catalysts are B203, BF3, and B(OCH3)3 because of their efficiency and availability.

The sulfur trioxide used in this process can be commercial, liquid sulfur trioxide, or it can be freshly distilled, unihibited sulfur trioxide. Commercial, liquid sulfur trioxide (mop~1 70C) is sold in sealed glass ampoules and contains a "stabilizer" which inhibits formation of solid, polymeric sulfur trioxide. For use in preparing the compounds of this invention the SO3 should be liquid at 200 C.

The general procedure for preparing the compounds of this invention involves addition of sulfur trioxide to a dry, heavy-walled glass tube or a metal tube having a corrosion-resistant liner such as a nickel alloy or stainless steel. Catalyst is added in the amount of about 0.1 to about 5% by weight relative to the sulfur trioxide (preferably about 0.3 to about 2.8% by weight), and hexafluoropropene is either pressured in or condensed in. The mole ratio of hexafluoropropene to sulfur trioxide can vary widely but is preferably about 1:1 to about 5:1. The reaction vessel is sealed and reaction carried out at temperatures from about 0 to about 1 500C (preferably about 25 to about 750C) under autogenous pressure for from about one hour to one week. Inert diluents may be used, but they offer no special advantage. Agitation is desirable but not essential.Protic materials such as water, hydrogen chloride, fluorosulfonic acid, methanol, etc. are deleterious to the reaction and should be avoided.

The time of reaction depends inversely on temperature. Although lower temperatures require a greater time for maximum yield, they favor perfluoroallyl fluorosulfate as product over hexafluoropropane sultone. Higher temperatures tend to decrease yields or perfluoroallyl fluorosulfate and increase the hexafluoropropene soltone content.

It has also been found that perfluoroallyl fluorosulfate and its sultone can be prepared with some batches of undistilled commercial sulfur trioxide without the addition of a trivalent boron compound. It is believed that the batches of sulfur trioxide which produce this result may contain an inhibitor which acts as a catalyst for this reaction. U.S. Patent 2,458,718 suggests that boron compounds have been used as inhibitors for sulfur trioxide.

Industrial Applicability The perfluoroallyl fluorosulfate of the present invention can be homopolymerized or copolymerized with various fluoroethylenes such as vinylidene fluoride, vinyl fluoride, trifluoroethylene, chlorotrifluoroethylene, and tetrafluoroethylene. Particularly preferred copolymers are those of vinylidene fluoride and perfluoroallylfluorosulfate. Generally the copolymer will contain from about 1 to about 80 and preferably about 5 to about 50 weight percent of the perfluoroallylfluorosulfate with a fluoroethylene comprising the remainder of the copolymer. The polymers find use as ion exchange resins and as acid catalysts. Aside from the sulfate group the polymers of the present invention are very temperature stable and chemically inert and, thus, do not interfere in the reaction catalyzed.They permit the use of corrosive or reactive reagents and furthermore permit the operation of the acid catalyzed reaction at high temperatures. Hydrolysis of the perfluoroallyl fluorosulfate polymer results in the formation of carboxylic acid groups. Thus, the polymer will contain repeating units of the structure

The advantage of this resin over mineral acid is the ready separation of the reaction products from the catalyst, the ability to regenerate the catalyst, the absence of mineral acid waste, and the noncorrosiveness of the catalyst.

The sultone of perfluoroallyl fluorosulfate can be rearranged to form P-fluorocarbonyl-P- fluorosulfonyltrifluoroethyl fluorosulfate on standing. This triacid fluoride product finds use as a catalyst for polymerizing tetrahydrofuran.

The sultone of perfluoroallyl fluorosulfate can also be reacted with water to form trifluorovinylsulfonyl fluoride which is useful for preparing ion exchange resins and acid catalysts as described by H. H. Gibbs and R. N. Griffin in U.S. Patents 3,041,317 and 3,624,053. The sultone can also be reacted with lower alkanols containing 1 to 8 carbon atoms to form dialkylfluorosulfonylfluoromalonates. Generally the reaction is carried out at from OOC to 600C using atmospheric pressure.

The products of the present invention and their preparation and use are illustrated by the following examples. All temperatures are in degree Celsius.

Example 1 Preparation of Perfluoroallyl Fluorosulfate and the Sultone of Perfluoroallyl Fluorosulfate A mixture of 10 ml of commercial liquid SO3 containing an unknown inhibitor and 45 g of HFP was sealed in a Carius tube at liquid nitrogen temperature, mixed well at room temperature and heated to 1 500 for four hours. From two such tubes there was obtained by distillation 26.5 g (23%) of 2 hydroxy-1 -trifluoromethyl-1 ,2,2-trifluoroethanesulfonic acid sultone, bp 450; 18.5 g (16%) of perfluoroallyl fluorosulfate, bp 590; and 1 6.4 g (21%) of the sultone of the latter, bp 1040.

Analysis For Perfluoroallyl Fluorosulfate CF=CF-CF20SO2F IR: 5.55 (C=C), 6.75 4 (SO3).

FMR: 46.1 ppm. (triplet, J=8.5 Hz to doublets, J=1 .8 Hz, 1 F), -74.0 ppm. (doublets, J=28.2 Hz, to doublets, J=1 3.9 Hz, to doublets, J=9.5 Hz, to doublets, J=7.8 Hz, 2F), -91.2 ppm. (doublet, J=50.0 Hz, to doublets, J=40.5 Hz, to triplets, J=7.8 Hz, 1 F), -104.7 ppm. (doublet, J=1 19.4 Hz, to doublets, J=50.0 Hz, to doublets, J=28.2 Hz), and -192.4 ppm. (doublet, J=1 19.4 Hz, to doublets, J=40.5 Hz, to triplets, J=1 3.9 Hz, to doublets, J=1 .8 Hz, 1 F).

For Sultone of Perfluoroallyl Fluorosulfate

IR: 6.70 6.93 y.

FMR: 50.1 ppm. (multiplet, iF), -78.0 ppm. (multiplet, 2F), -81.9 ppm., -83.9 ppm., -88.6 ppm., -90.6 ppm. (AB pattern, 2F), -152.4 ppm. (multiplet, 1 F).

Anal. Calcd. for C3F6S2O6: C, 11.62; F; 36.77.

Found: C, 12.04; F, 37.81.

Example 2 Each of the four Carius tubes (1 50 ml capacity) was charged with 10 ml (1 9 g) of sulfur trioxide (stabilized with dimethyl phthalate) and 12 drops (0.12 g) of trimethyl borate, cooled with liquid nitrogen, necked down and evacuated. Hexafluoropropene (45 g) was condensed into each tube which was then sealed and warmed to melt and mix the contents. They were heated for 14 hrs in a water bath at 55--60". Analysis of the product by gas chromatography (gc) indicated that the major product was perfluoroallyl fluorosulfate (FAFS).The combined product of the four tubes was fractionally distilled to give 45 g, b.p. mostly 450, analyzing by gc 75% 2-hydroxy-1 -trifluoromethyl-1 ,2,2- trifluoroethanesulfonic acid sultone (HFPS) and 25% FAFS; 80 g, b.p. mostly 620, analyzing by gc 95% FAFS; and 44 g of high-boiler not characterized. Based on SO3 charged, the total yield of HFPS was 14.8% and of FAFS 39.6%.

For comparison, the above experiment was repeated except that no trimethyl borate catalyst was added. Analysis of the product by gc indicated that the major product was HFPS and no FAFS was detected.

Example 3 The following reactions in which distilled SO3 was employed were carried out in 1200-ml Hastalloy (Registered Trade Mark) lined metal tubes. Yields quoted are for product isolated by conventional distillation techniques. The results are summarized in the following table.

Cl:3 CF- CF2 II SO3 CF3CF=CF2 Catalyst Temp. and CF2=CFCF2OSO2F SO2O (moles) (moles) (g) Time (% yield) (% yield) 3.1a 3.5 None 600/22 hr; 0 86 then 40 1000/2 hr 2.7 3.5 1.0 250/3days; 44 13 B(OCH3)3 then 1000/8 hr 2.0 3.5 0.7 250/5 days; 60 10 45 B(OCH3)3 600/8 hr; then 1000/2 hr 2.1 3.5 2 BF3 25 /5 > days; 60 5 60 /8 hr; 50 then 100012 her 2.1 3.5 0.5 B203 600/22her; 25 42 then 1000/2 hr 55

a. The distilled S03 was chilled at 0 until it solidified to trimer, m.p. 170, then melted at 250 to the normal state prior to reaction.

Example 4 A 1200-ml Hastalloy-lined tube charged with 240 g (3.0 mol) of SO3, 3 g of BF3, and 525 g (3.5 mol) of hexafluoropropene was agitated briefly, then allowed to stand at 250C for 3 days. After having been heated at 1 000C for 8 hr, the tube was cooled at OOC while gases were vented. Liquid products were collected and fractionated in a spinning band still to afford 61.3 g (9%) of crude sultone, b.p.

46--600; 146.9 g (21%) of perfluoroallyl fluorosulfate, b.p. 600 (1 atm) 440 (350 mm); and 155.4 g of high boiling mixture, b.p. 49--560 (50 mm). Analysis of the mixture by 19F NMR indicated a threecomponent mixture 82.9 g (18%) of tetrafluoropropenyl-1,3-bis(fluorosulfate), 56.8 g (12%) of 2:1 sultone

and 1 5.7 g of FSO2OSO2OSO2F.

A center cut of the above high-boiling fraction (64.6 g) was added to 1 50 ml of diethyl ether at 50, and the mixture was stirred overnight at room temperature. Fractionation afforded 36.0 g of pure FSO2OCF2CF=CFOSO2F, b.p. 521 55 (50 mm). IR (CCl4: 5.67 (C=C) and 6.72 y (OSO2F). 19F NMR fit a 1:1.3 mixture of cis/trans isomers of FSO2OCF2CF2=CFOSO2F.

Anal. Calcd. for C3F606S2: F, 36.76.

Found: F, 36.74.

Example 5 A 1 200-ml Hastalloy tube charged with 1 67 g (2.09 mol) of distilled S03, 2 g of boron trifluoride, and 525 g (3.5 mol) of hexafluoropropene was agitated at 250 for 5 days, then at 600 for 8 hr, and at 1000 for 2 hr. The tube was cooled to 00, gases were vented, and the reaction mixture was fractionated to afford 21.9 g (5%) of crude hexafluoropropene sultone, bp 30--610, and 288.0 g (60%) of perfluoroallyl fluorosulfate, bp 61--630. The perfluoroallyl fluorosulfate was identified by comparison of its IR spectrum with that of the corresponding product of Example 1.

Example 6 Copolymerization of Perfluoroallyl Fluorosulfate with Vinylidene Fluoride A mixture of 11 g of perfluoroallyl fluorosulfate, 6.5 g of vinylidene fluoride and 50 microliters of a catalyst solution containing ca. 6% perfluoropropionylperoxide in 1,1 ,2-trichloro-1 ,2,2- trifluoroethane was sealed in a glass tube and rotated at room temperature for five days. When cooled, opened, and low-boiler removed, there was recovered 9.8 g of an elastomer which was soluble in acetone and also in dimethylformamide. Transparent films could be cast from acetone solution or pressed from the solid polymer. Their infrared absorption showed the presence of fluorosulfate (-OSO2F) groups.

Example 7 Copolymerization of Perfluoroallyl Fluorosulfate with Vinylidene Fluoride In an experiment like the one above, but using 5.5 g of perfluoroallyl fluorosulfate, 5.5 g of vinylidene fluoride and 50 microliters of the catalyst solution, there was obtained 10.5 g of polymer in 60 hrs.

Example 8 Copolymerization of Perfluoroallyl Fluorosulfate with Tetrafluoroethylene A mixture of 11 g of perfluoroallyl fluorosulfate, 9 g of tetrafluoroethylene and 50 microliters of the catalyst solution sealed in a glass tube for 1 6 hours at room temperature gave 4 g of the copolymer of tetrafluoroethylene and perfluoroallyl fluorosulfate and 13.5 g of volatiles.

Example 9 Copolymerization of Perfluoroallyl Fluorosulfate with Vinyl Fluoride A mixture of 11 g of perfluoroallyl fluorosulfate, 4.5 g of vinyl fluoride and 50 microliters of the catalyst solution sealed in a glass tube at room temperature gave 5.2 g of a dark copolymer of perfluoroallyl fluorosulfate and vinyl fluoride and 4 g of volatile material.

Example 10 Rearrangement of the Sultone of Perfluoroallyl Fluorosulfate to p-FIuorocarbonyl-p- fluorosulfonyltrifluoroethyl

A sample of the above soltone which had been standing for several months in a glass bottle was redistilled. After distilling recovered sultone (b.p. 670 100 mm), there was distilled the rearranged product, P-f luorocarbonyl-P-fl uorosulfonyltrifl uoroethyl fluorosulfate, b.p. 840/30 mm.

Analysis FMR: 51.7 ppm. (doublet, J=5.2 Hz, 1 F), 50.6 ppm. (triplet, J=8.2 Hz, iF), 33.0 ppm. (doublet, H=22.5 Hz, to triplet, J=7.8 Hz, iF), -75.5 ppm. (doublet, J=8.2 Hz, to doublet, J=7.8 Hz, to doublet, J=7.5 Hz, 2F), -155.7 ppm. (doublet, J-J=22.5 Hz to triplet, J=7.5 Hz, to doublet, J=5.2 Hz, 1 F).

Example 9 Reaction of the Sultone of Perfluoroallyl Fluorosulfate with Water to form Trifluorovinylsulfonyl Fluoride

,B-hydro-ss-fluorosu Ifonyl-Trifl uorovi nylsu If onyx trifl uoroethyl fl uorosu Ifate fluoride.

The above sultone (62 g, 0.2 m) was stirred with cooling to keep the temperature in the range of -10 to +200C while adding dropwise 14.4 ml of H20. The mixture was heated under vacuum and the product was condensed in a dry ice trap. Material in the trap was distilled to give 1 6 g (46%) of trifluorovinylsulfonyl fluoride, b.p. 530, and 9.6 g (18%) of p-hydro-4- fluorosulfonyltrifluoroethylfluorosulfate, b.p. 740/70 mm.

Analysis For p-hydro-,l3-fl uorosulfonyltrifluoroethylfluorosulfate IR: 6.70, 6.86 (SO2). PMR: 5.64 ppm. (doublet J=44.5 Hz to triplets, J=6.1 Hz to doublet, J=2.5 Hz, 1 H). FMR: 49.1 ppm. (triplet, J=8.4 Hz to doublet, J=1.0 Hz, 1 F), 52.6 ppm. (triplet, J=9.7 Hz, to doublet, J=6.7 Hz to doublet, J=2.5 Hz, 1 F), -77.9 ppm. (multiplet, 2F) and -190.5 ppm. (doublet, J=44.5 Hz, to triplet, J=1 2.3 Hz, to doublets, J=6.7 Hz, to doublets, J=1.0 Hz, 1 F).

Anal. Calcd.forC2HF5S2O5: C, 9.10; H, 0.38; F, 35.98; S, 24.29.

Found: C, 9.30; H, 0.40; F, 35.94; S, 25.20.

For Trifluorovinylsulfonyl Fluoride IR: 5.70 4 (C=C), 6.80 y (SO2). FMR: 61.2 ppm. (doublet, J=1 3.8 Hz, to doublet, J=5.3 Hz to doublet, J=4.1 Hz, iF), -88.5 ppm. (doublet, J=43.0 Hz, to doublet, J=1 7.0 Hz, to doublet, J=1 3.8 Hz, 1 F), -90.9 ppm. (doublet, J=1 21.8 Hz, to doublet, J=1 7.0 Hz, to doublet, J=4.1 Hz, 1 F) and -180.9 ppm. (doublet, J=1 21.8 Hz, to doublet, J=43.0 Hz, to doublet, J=5.3 Hz, 1 F).

Anal. Calcd.forC2F4SO2: C, 14.65; F, 46.34; S, 19.55.

Found: C, 14.60; F, 45.91; S, 17.29.

Claims

1. A composition of matter consisting essentially of perfluoroallyl fluorosulfate of the formula CF2=CFCF2OSO2F.

2. The sultone of perfluoroallyl fluorosulfate having the formula

3. Process for preparing perfluoroallyl fluorosulfate according to Claim 1 which comprises reacting hexafluoropropene with sulfur trioxide in the presence of 0.1 to 5% by weight, based on the sulfur trioxide, of a trivalent boron compound, the reaction being carried out under anhydrous conditions at a temperature from 0 to 1 500C, and thereafter recovering the perfluoroallyl fluorosulfate from the reaction mixture.

4. Process according to Claim 3 in which the boron compound is boric oxide.

5. A process according to Claim 3 in which the boron compound is boron trifloride.

6. Process according to Claim 3 in which the boron compound is trimethyl borate.

7. Process according to Claims 3-6 in which the ratio of hexafluoropropene to sulfur trioxide is 1:1 to 5:1.

8. Process according to Claims 3-7 in which the temperature of the reaction is 250--750C.

9. Process according to Claims 3-8 in which the reaction is carried out under autogenous pressure.

10. Process according to Claims 3-9 in which the sultone of perfluoroallyl fluorosulfate is recovered from the reaction mixture.

11. Process according to Claim 3 substantially as described in any one of Examples 1 to 5.

12. Perfluoroallyl fluorosulfate when prepared by the process of any of Claims 3 to 11.

13. The sulfone of perfluoroallyl fluorosulfate when prepared by the process of Claim 1 0.

14. A homopolymer containing repeating units of the structure

derived from perfluoroallyl fluorosulfate.

15. Copolymers of fluoroethylenes and 1 to 80% by weight of perfluoroallyl fluorosulfate.

1 6. A copolymer according to claim 15, wherein the fluoroethylene is vinylidene fluoride.

17. A copolymer according to claim 15, wherein the fluoroethylene is tetrafluoroethylene.

1 8. A copolymer according to claim 15, wherein the fluoroethylene is vinyl fluoride.

19. A copolymer according to claim 1 5 substantially as described in any one of Examples 6 to 9.