WO1992006942A1

WO1992006942A1 - Process for production of polyfluoroolefins

Info

Publication number: WO1992006942A1
Application number: PCT/US1991/007242
Authority: WO
Inventors: Carl George Krespan
Original assignee: E.I. Du Pont De Nemours And Company
Priority date: 1990-10-11
Filing date: 1991-10-10
Publication date: 1992-04-30
Also published as: KR100219099B1; CN1030908C; KR930702259A; JP3162380B2; ZA918128B; MX9101544A; AR247874A1; JPH07502254A; TW324710B; CN1061399A

Abstract

This invention concerns a process for the production of polyfluoroolefins by the catalytic addition of polyfluoroallylic fluorides to fluoroéthylenes. 1:1 and 1:2 adducts such as F-pentene-2 and F-heptene-3 can be formed selectively and reduced further to dihydro- or trihydropolyfluoroalkanes, which are useful as HFC cleaning agents.

Description

TITLE

PROCESS FOR PRODUCTION OF POLYFLUOROOLEFINS

CROSS-REFERENCE TO RELATED APPLICATION This is a continuation-in-part of Serial No.

595,839 filed October 11, 1990.

BACKGROUND OF THE INVENTION

1. Field of the Invention:

This invention concerns a process for the production of polyfluoroolefins by the catalytic addition of polyfluoroallylic fluorides to fluoroethylenes. 1:1 and 1:2 Adducts such as F-pentene-2 and F-heptene-3 can be formed selectively and reduced further to dihydro- or trihydropolyfluoroalkanes, which are useful as HFC cleaning agents. Higher boiling products, e.g., boiling points above 100°C are useful as solvents and stable liquids, particularly after the double bond has been saturated by hydrogenation, fluorination, or

chlorination.

2. Technical Review:

Various catalysts for the addition of polyfluoroallylic fluorides to fluoroethylenes are known.

G.G. Belen'kii, E.P. Lur'e, and L.S. German, UDC 66.095.253:547.413, Institute of Heteroorganic

Compounds, Academy of Sciences of the USSR, Moscow

(1975) use SbF₅ as a catalyst for carrying out the alkylation of the fluoro derivatives of ethylene using perfluoropropylene and 2-H-perfluoropropylene.

Chang-Ming Hu, Hui Liu and Ze-Qi Xu, Reactions of Perchlorofluoro Compounds VI. Rearrangement of Higher Perchlorofluoroolefins and Their Reactions with Nucleophiles and Electrophiles, teaches the alkali fluoride ion induced formation of a TFE/HFP adduct. The present invention employs an aluminum halide to catalyze the addition of an allyl fluoride to

fluoroethylene.

SUMMARY OF THE INVENTION

The present invention provides a process for the manufacture of polyfluoroolefins having at least 5 carbon atoms comprising reacting a first polyfluoroolefin of the structure

where:

R₁ is F, Cl, H or R_f;

R₂ is F, Cl, H or R_f;

R₃ is F, Cl, or H;

R_f is a C₂ to C₁₂ perfluoroalkyl, optionally containing 1 H or 1 Cl;

R₄ is F or R_f or where R₄ together with R₂ is -(CF₂)n-; wherein n is 1, 2 or 3;

with a second polyfluoroolefin of structure R₅CF=CF₂ and where

R₅ is F, H, or Cl;

in the presence of a catalyst of the structure AIX₃ where X is one or more of F, Cl or Br, provided that X cannot be entirely F.

The invention also concerns olefins of the

structures

R₁R₂C=CR₃CFR₄

CFR₅CF₃ and R₁R₂CC (R₃) =CFR₄ CFR₅CF₃ or structures derived therefrom by further "migration" of the double bond. By "migration" is meant a shift in the double bond position in the molecule accompanied by relocation of fluorine .

The invention also concerns olefins of the structures :

or rearrangement products resulting from a shift of the double bond. (These later olefins result where R₄, together with R₂ is -(CF₂)_n- in the starting

compound) where n is 1, 2 or 3.

DETAILED DESCR I PTION OF THE INVENTION

The equation for the addition reaction which is claimed is as follows (where R₄ is F):

where R₁, R_2, R₃ and R₅ are as defined in the Summary of the Invention.

The allylic fluoride may either have the structure shown or be capable of rearranging to that structure by fluorine atom migration in the presence of a catalyst.

The product may also either have the structure shown or a structure resulting from fluorine atom migration. In some cases isomefic products, such as

R₃ R₅

R₁R₂CFC=CFCFCF₃, are formed.

The catalyst used is of the structure AIX₃, where X is one or more of F, Cl or Br, with a proviso that X cannot be entirely F. Active catalyst can be preformed, as in most examples, or can be formed in situ by partial halogen-F exchange with allylic fluoride, as in Examples 9 and 20. Preferred catalysts are AlF_xCl_y (mixed aluminum halide), where the total number of atoms of halide, x plus y equals 3, where x ranges from 0 to about 2.95 and y ranges from 3 to about .05. The

AlFxCly, where y is greater than 0, may be prepared by pretreating AICI₃ with reactive C-F compounds such as CF₃CF=CF₂, CFCI₃ or CHFCI₂.

Temperatures range from -20°C to 150°C, depending on the reactivity of the reagents but are preferably in the range of 20ºC to 85°C. Pressures may vary from less than 1 atm to over 50 atm, but a preferred range is from 1 atm to 20 atm. Times for batch reactions may vary from about 5 min. to about 2 days depending on batch size. Times for a continuous reaction may vary from about 1/2 to 120 min. Times for the reaction vary depending upon the identity of the reactants, the temperature, pressure and amount of catalyst.

The reaction is best conducted in a liquid phase and can be carried out in several modes; batchwise with addition of reactants and catalyst to a reactor cold and warming to reaction temperature; semibatch by injection of one or both reactants optionally containing catalyst into a vessel containing catalyst and or the other reagent at reaction temperature; or continuous by passing the reactants (preferably at least partly liquified, optionally with catalyst) through a reaction zone, which also optionally contains catalyst. The catalyst must be present in the reactant mixture or the reaction zone but may be present in both places.

Reactant mole ratios of allylic fluoride (e.g., HFP) to fluoroolefin (e.g., TFE) can vary from 5:1 to 1:50.

Ratios in the 5:1 to 1:1 range are generally used when high yields of one to one adducts are desired. Ratios from 1:1 to 1:50 are used when multiple additions of fluoroethylene are desired to form one-to-two and higher adducts, especially when the fluoroolefin is

tetrafluoroethylene (TFE). Catalyst loadings in a batch reaction can be from about 0.5 to about 20 wt-%, preferably 2-8 wt-%, of the total charge of reactants.

Solvents are generally not essential, but a liquid phase is useful to facilitate reaction of low-boiling materials that are not condensed under reaction

conditions. Solvents are also useful for controlling any initial exotherm when a catalyst, such as aluminum chloride, is used in a large scale reaction. Relatively inert materials which may be used as solvents include hexafluorobenzene, E-n-hexane, CICF₂CF₂CI, SO₂CIF,

CF₃CF₂CHCI₂, CICF₂CF₂CHFCI, CF₃CHFCHFCF₂CF₃, CF₃CHFCH₂CF₂CF₃, CF₃CH₂CHFCF₂CF₃, CICF₂CFCI₂, CF₃CCI₃, CF₃CCl₂CF₃, CF₃CHCI₂, F-1,2-dimethylcyclobutane,

CCI₂=CCI₂, CCI₂=CHCI, CF₃CF₂CF₂O[CF(CF₃)CF₂O]_nCHFCF₃, (CF₃)₂C=CFCF₂CF₃, (CF₃)₂CFCF=CFCF₂, F-pentene-2,

F-heptene-3, F-heptene-2, and C_nF_2n, where n is 9 or greater. Highly fluorinated olefins are preferred solvents and perfluoroolefins, C_nF_2n, wherein n is 5 or greater are most preferred. F-pentene-2, for example, is especially preferred for the reaction in which it is also the product, i.e. the condensation of CF₃CF=CF₂ with CF₂=CF₂, since the reaction mixture can be over 95% C₅F₁₀, and therefore easily purified. Selectivity in this procedure is high because CF₃CF=CF₂ is much more reactive than CF₃CF=CFCF₂CF₃ and, when present, reacts with CF₂=CF₂, almost exclusively.

Table I shows various examples and reaction conditions. It should be noted that some of the entries in Table I, in which large excesses of tetrafluoroethylene (TFE) over hexafluoropropene (HFP) were used, resulted in appreciable condensation of TFE with itself to yield even numbers of carbon atoms in product fluoro- olefins. Also, as multiple additions of TFE to HFP increase in number, branching in the product olefins becomes more pronounced. Thus, C₅F₁₀ and C₇F₁₄ are linear products, C₉F₁₈ is mainly linear, C₁₁F₂₂ and higher have increasing amounts of structures of the type (R_f)₂C=CFR_f. These mixtures of high-boiling liquids are converted to even higher boiling, stable liquids by hydrogenation, chlorination or fluorination.

The synthesis described herein can be used to form 1:1 and 1:2 adducts such as F-pentene-2 (CF₃CF=CFCF₂CF₃) and F-heptene-3/F-heptene-2 mixtures which can be reduced to form HFC cleaning agents. It can also be used to form higher adducts useful as a source of unreactive solvents, vapor degreasing agents, and stable liquids by chlorination, fluorination or hydrogenation of the double bond.

EXAMPLES

Catalyst preparation - AlCl₃+CF₃CF=CF₂

A slurry of 100 g (0.75 mol) of AICI₃ (Aldrich,

99.9% pure) in 100 mL of CCI₄ was stirred under nitrogen under a -80°C condenser while 20 g (0.13 mol) of

CF₃CF=CF₂ was bled in over 1.75 hr. Some unreacted hexafluoropropene, which was present at the end and caused the temperature to drop to 5°C, was bled off, and the mixture was warmed to 40°C. Another addition of 11 g (0.07 mol) of CF₃CF=CF₂ over a 1 hr period resulted in an exotherm to 50°C. Continued slow addition at 50-65°C of 42 g (0.28 mol) of CF₃CF-CF₂ finally resulted in persistent reflux of unreacted CF₃CF=CF₂. The reaction mixture was transferred to a dry box, where it was filtered. The filter cake was rinsed with 2 X 50 mL of dry CCI₄, then dried under vacuum to afford 84.7 g of greenish, free-flowing powder.

Catalyst Preparation - AICI₃+CFCI₃

500 g (3.75 mol) of AICI₃ (Aldrich-99% pure) was stirred mechanically under N₂ in a r.b. flask fitted with a -80°C condenser while 1750 mL (-2625 g, 19 mol) of CFCI₃ was added over a 1.5-hr period. Reaction is very exothermic in the early stages, so addition of CFCI₃ was slow at first in order to keep the temperature below 65°C, then rapid. The resulting suspension was stirred an additional 3 hrs while volatiles (CF₂CI₂) were allowed to escape through the warmed condenser. The condenser was then replaced with a simple stillhead, and most of the CCI₄ was distilled under reduced

pressure [mainly bp 38°C (200 mm)]. Finally, the last traces of volatiles were removed by warming the residual solid to 30-35ºC at 0.05 mm.

The sealed r.b. flask was transferred to a dry box and unloaded into a Teflon^® FEP bottle; 340 g of rather finely divided yellow-green solid. Portions of the catalyst were weighed out in the dry box as needed and taken out in plastic bottles with pressure-seal caps.

Analysis for fluorine of the products from

preparation of this type indicated the composition to be AIF_2.9CI_0.1, AlF_xCl_y; X = 2.8-2.9, Cl = 0.2-0.1.

EXAMPLE 1

A 400-mL metal tube charged with 16.4 g of

fluoridated AICI₃ (AICI₃ + CFCI₃), 100 g (0.5 mol) of 1,1,2-trichloro-3,3,3-trifluoropropene, and 50 g

(0.50 mol) of tetrafluoroethene was agitated at 25ºC for 1.5 hr . Fractionation of the liquid product mixture gave 25.4 g (25%) of recovered CF₃CCI=CCI₂, then 42.3 g (38% yield) pf F-1, 1, 2-trichloropentene-1, bp 63-66°C

(100 mm) , identified by IR, NMR and GC/MS . Further fractionation afforded 23.3 g (15%) of an isomeric mixture of F-1, 1, 2-tetrachloropentene-1 and F-1, 1, 1-2- tetrachloropentene-2, bp 86-89°C (100 mm) , identity indicated by IR, NMR and GC/MS . Some higher boiling 2 : 1 adducts were also present .

The equation for the reaction is shown below: CF₃CCl=CCl₂ + CF₂=CF₂

CF₃CF₂CF₂CCl=CCl₂

+ CF₃CF₂CFClCCl=CCl₂ + CF₃CF₂CF=CClCCl₃ EXAMPLE 2

A 400-mL metal tube charged at -20ºC with 8.0 g of AIF_2.8CI_0.2 (prepared from AICI₃ + CFCI₃), 75 g (0.50 mol) of hexafluoropropene (HFP), and 50 g (0.50 mol) of tetrafluoroethylene (TFE) was shaken for 30 min. while the temperature rose quickly to 20ºC and the pressure dropped to 8 psi. Distillation of the product afforded 88.0 g (70%) of F-pentene-2, b.p. 23-26ºC, identified by IR, NMR and GC/MS. NMR showed the product to be 89% trans-isomer and 11% cis-isomer.

EXAMPLE 3

Reaction of CF₃CF=CF₂/CF₂=CF2 in 1:2 Ratio

A 400-mL metal tube charged cold with 3 g of

AlF_xCl_y (fluorinated aluminum chloride catalyst prepared by treating aluminum chloride with CFCI₃), 40 g

0.27 mol) of hexafluoropropene, and 50 g (0.50 mol) of tetrafluoroethylene was agitated at 25°C for 2 hr and at 80°C for 4 hr. Analysis of the liquid product, 73 g, by GC and MS indicated the presence of 28.2 g (42%) of perfluoro-pentene-2, 42.2 g (48%) of perfluoroheptene isomers, 2.7 g (4%) of perfluorononene isomers, <0.7 g (1%) of C₁₁F₂₂ isomers, and traces of higher oligomers, with very small amounts of perfluorohexene and

perfluorooctene also detected. Fractionation afforded 21.9 g (32%) of perfluoropentene-2, bp 24-26ºC, followed by 34.1 g (39%) of perfluoroheptenes, bp 69.5-71ºC.

Analysis of a center cut, bp 70.9ºC, by IR and NMR showed the major component to be trans-perfluoro- heptene-3 with only small amounts of other isomers present. Continued fractionation afforded 1.2 g (2%) of perfluorononenes, bp 66-68ºC (150 mm), shown by IR and NMR to consist mainly of trans-perfluorononene-4 and trans-perfluorononene-3. EXAMPLE 4

Reaction of CF₃CF-CF₂/CF₂=CF₂ in 1:4 Ratio A 400-mL tube charged cold with 5.0 g of AlF_xCl_y, 40 g (0.27 mol) of hexafluoropropene, and 50 g (0.50 mol) of tetrafluoroethylene was shaken at 25°C for 30 min. while the pressure dropped to 0 psi. Another 50 g (0.50 mol) of tetrafluoroethylene was added, and the mixture was agitated for 4 br at 25°C while the pressure again fell to 0 psi. Analysis of the liquid product, 122 g, by GC and MS indicated the presence of 34.5 g (37% yield) of perfluoroheptenes, 59.0 g (49% of

perfluorononenes, 22.2 g (15%) of perfluoroundecenes, and 2.0 g (1%) of perfluorotridecenes, with 0.5-1% of perfluoroolefins having even numbers of carbon atoms C₆F₁₂, C₈F₁₆ and C₁₀F₂₀ also detected. Distillation afforded a series of fractions, bp 66°C (1 atm) to 66°C (18 mm), which were characterized by GC, IR and NMR analysis. Product boiling at 71-72ºC was shown to consist of straight-chain trans-perfluoroheptene-3 and trans- and cis-perfluoroheptene-2, with very small amounts of branched olefins (e.g., CF₃CF₂C(CF₃) =

CFCF₂CF₃) present. Product with bp 74-80ºC (200 mm) was found to be mainly staight-chain trans-perfluorononene-4 and trans -perfluorononene-3, with perhaps 50% of branched perfluorononenes present in a fraction bp 74°C (200 mm) dropping to about 5% branched olefins in fractions bp 76-80ºC (200 mm). The mixed

perfluoroundecenes with bp 70-77°C (50 mm) were shown to be mainly branched structures of the type (R_f)₂C=CFR_f, with linear olefins R_fCF=CFR_f as minor components.

EXAMPLE 20

Reaction of Equimolar CF₃CF=CF₂ with CF₂=CF₂ with AICI₃ Catalyst in CCl₂=CCl₂ Solvent

A tube charged cold with 5.0 g of aluminum

chloride, 100 mL of tetrachloroethylene, 759 (0.50 mol) of hexafluoropropene, and 50 g (0.50 mol) of

tetrafluoroethylene was shaken at 25-30ºC for 4 hr while the pressure dropped to 69 psi. The reaction mixture was then heated at 60°C for 10 hr while the pressure fell to 45 psi. The liquid product, two phases, was distilled to give a foreshot of 4 mL followed by 58.4 g (47%) of perfluoroρentene-2, bp 10-25ºC, nearly 100% pure by GC.

Tetrachloroethylene is a preferred solvent because of its availability, relative inertness under reaction conditions, and ease of separation from low boiling 1:1 and 1:2 adducts.

EXAMPLE 21

Addition of CF₂=CF₂ to F-Cyclopentene

A 1-L. stirred autoclave was charged with 30 g of AlF_xCl_y and 118 g (0.56 mol) of F-cyclopentene.

Tetrafluoroethylene (47.3 g, 0.47 mol) was pressured in and the vessel was heated slowly with stirring to 80°C, where reaction rate was appreciable. Tetrafluoroethylene was added in portions at 80°C until a total of

114.4 g (1.14 mol) had been added over 14 hr. Reaction was continued another 7 hr. Volatiles obtained by heating the crude reaction product at 100°C (0.3 mm) were 122.6 g of liquid. Fractionation afforded 96.2 g (55%) of F-1-ethylcyclopentene, bp 64-66°C, identified by IR and NMR analysis. EXAMPLE 22

Addition of CF₂-CF₂ to F(CF₂)₄CH=CH(CF₂)₄F

A metal tube charged with 5 g of AlF_xCl_y, 50 g (0.50 mol) of CF₂=CF₂, and 139 g (0.30 mol) of

F(CF₂)4CH=CH(CF₂)₄F was shaken at 25°C for 17 hr. The reaction mixture was filtered and distilled to give 90.5 g (54%) of 1:1 adducts, bp 60-63ºC (20 mm),

identified by GC/MS. The major isomer, about 95% of the total, was shown to be

CF₃CF₂CF₂CF=CHCH (CF₂CF₃) CF₂CF₂CF₂CF₃ by IR and NMR analysis.

EXAMPLE 23

Use of CF₃CF=CFCF₂CF₃ as Solvent

A 400-mL metal tube charged with 5.0 g AlF_xCl_y,

49.5 g of CF₃CF=CFCF₂CF₃, 75 g (0.50 mol) of CF₃CF=CF₂, and 50 g (0.50 mol) of CF₂=CF₂ was agitated as it warmed over 0ºC. From a peak pressure (115 psig) at 16°C, the pressure fell rapidly to 9 psig, while a slight exotherm carried the temperature to 28°C before subsiding to 22°C, all in 1 hr. Heating at 60°C produced no further sign of reaction. GC analysis of the crude product, 169 g, indicated that 110.1 g (88%) of C₅F₁₀ had been formed. Only small amounts of by-products such as hexafluoro- propene dimer were present.

Although preferred embodiments of the invention have been described hereinabove, it is to be understood that there is no intention to limit the invention to the precise constructions herein disclosed, and it is to be further understood that the right is reserved to all changes coming within the scope of the invention as defined by the appended claims.

Claims

CLAIMS What is claimed:

1. A process for the manufacture of

polyfluoroolefins having at least 5 carbon atoms

comprising reacting a first polyfluoroolefin of the structure

where:

R₁ is F, Cl, H or R_f;

R₂ is F, Cl, H or R_f;

R₃ is F, Cl or H;

R_f is a C₂ to C₁₂ perfluoroalkyl, optionally containing 1 H or 1 Cl;

R₄ is F or R_f or where R₄ together with R₂ is -(CF₂)_n-; wherein n is 1, 2 or 3;

with a second polyfluoroolefin of structure R₅CF=CF₂ and where

R₅ is F, H or Cl; in the presence of a catalyst wherein the catalyst is of the structure AIX₃ wherein X is one or more of F, Cl or Br, provided that X cannot be entirely F.

2. The process of Claim 1 carried out within a temperature range of -20°C to 150°C.

3. The process of Claim 2 wherein the temperature is 0°C to 100°C.

4. The process of Claim 1 carried out at 1 atm. pressure.

5. The process of Claim 1 carried out in a batch process for about 5 min. to about 2 days.

6. The process of Claim 1 carried out in a continuous process for 1/2 min. to 120 min.

7. The process of Claim 1 wherein the reactants and catalyst are placed batchwise in a cold reactor then warmed to reaction temperature.

8. The process of Claim 1 wherein the reaction is carried out semibatchwise by injection of one or both reactants into a vessel containing catalyst at reaction temperature.

9. The process of Claim 1 wherein the reaction is carried out semibatchwise by injection of one reactant and catalyst into a vessel containing the other reactant or containing the other reactant and additional

catalyst.

10. The process of Claim 1 wherein the process is run as a continuous reaction by passing the reactants through a reaction zone containing catalyst.

11. The process of Claim 10 wherein the reactants are at least partly liquid.

12. The process of Claim 1 wherein the process is run as a continuous reaction by passing at least partially liquid reactants containing catalyst through a reaction zone.

13. The process of Claim 11 wherein the at least partially liquid reactants also contain catalyst.

14. The process of Claim 1 carried on in a

relatively inert solvent.

15. The process of Claim 14 wherein the solvent is selected from hexaflυorobenzene, F-n-hexane, ClCF₂CF₂Cl, SO₂CIF, CF₃CF₂CHCI₂, CICF₂CF₂CHFCI, CF₃CHFCHFCF₂CF₃, CF₃CHFCH₂CF₂CF₃, F-pentene-2, CF₃CH₂CHFCF₂CF₃, CICF₂CFCI₂, CF₃CCI₃, CF₃CCI₂CF₃, CF₃CHCI₂, perfluoro-1,2- dimethylcyclobutane, CCl₂=CCl₂, CCl₂=CHCl, C_nF₂n wherein n is equal to or greater than 5 and

CF₃CF₂CF₂O[CF (CF₃) CF₂O₃]_nCHFCF₃.

16. The process of Claim 14 wherein the relatively inert solvent is C_nF₂n, wherein n is greater than or equal to 5.

17. Process of Claim 16 wherein the solvent is CF₂CF-CFCF₂CF₃.

18. Process of Claim 15 wherein the solvent is

F-pentene-2.

19. The process of Claim 2 wherein the reactants are:

where :

R₁ is F, Cl, H or R_f; and

R₃ is F, Cl, H or R_f .

20. The process of Claim 1 wherein the first fluoroolefin is hexafluoropropene (HFP) and the second polyolefin is tetrafluoroethylene (TFE).

21. Process of Claim 17 wherein an excess of TFE over HFP is used.

22. The process of Claim 1 wherein an excess of first polyfluoroolefin over second polyfluoroolefin is used.

23. The process of Claim 19 wherein the ratio of HFP to TFE varies from 5:1 to 1:50.

24. The process of Claim 23 wherein the ratio of HFP to TFE is from 1:2 to 1:50 and wherein some of the product fluoroolefins contain even numbers of carbon atoms.

25. The process of Claim 23 wherein the ratio of HFP to TFE is from 2:1 to 1:50 and wherein some of the product fluoroolefins contain branching.

26. Isomeric compositions of the structures :

wherein R₁, R₃, R₅, and n are as defined in Claim 1.

27. Liquid phase mixtures comprising

perfluorinated olefins of the formula C_mF_2m where m is an integer greater than or equal to 9, as prepared by the process of Claim 20.

28. A composition of the structure

CF₃CCl=CClCF₂CF₂CF₃.

29. A composition of the structure

CF₃CF₂CF₂CCI=CCICF₂CF₂CF₃.

30. The process of Claim 1 wherein the catalyst is AICI₃.

31. The process of Claim 1 wherein the catalyst is AlF_xCl_y, wherein the total number of atoms halide x plus y equals 3 and wherein x ranges from 0 to about 2.95 and y ranges from 3 to about .05.