WO2019115654A1

WO2019115654A1 - Process for the production of perfluorinated alkylvinylethers

Info

Publication number: WO2019115654A1
Application number: PCT/EP2018/084645
Authority: WO
Inventors: Cristiano Monzani; Vito Tortelli
Original assignee: Solvay Specialty Polymers Italy S.P.A.
Priority date: 2017-12-15
Filing date: 2018-12-12
Publication date: 2019-06-20

Abstract

The present invention relates to a process for producing a perfluorovinylether A-CRf=CF-O-B, comprising the steps of : - contacting at least one α,β-dihaloperfluoro ether represented by the formula A-CRfX-CFX-O-B with zero valent zinc in the presence of an organic nitrogen compound selected in the group consisting of: tertiary aliphatic amines; aromatic heterocycles comprising nitrogen as heteroatom; and guanidines; to form a mixture comprising perfluorovinylether, and - recovering the perfluorovinylether from the mixture, wherein : X is selected from the group consisting of chlorine, bromine, or iodine, Rf is fluorine or is a group of formula –OR'f, where R'f is selected from the group consisting of linear and branched chain perfluoroalkyl radicals A is selected from the group consisting of fluorine and linear and branched chain perfluoroalkyl radicals, and B is selected from the group consisting of linear and branched chain perfluoroalkyl radicals, wherein A and B can contain oxygen and sulfur heteroatoms configured in functional groups selected from ether, ester, ketone, and sulfonyl fluoride, and wherein A and B can be bonded together forming a ring.

Description

PROCESS FOR THE PRODUCTION

OF PERFLUORINATED ALKYLVINYLETHERS

Cross-Reference to Related Application

This application claims priority to European application N° 17207733.1 filed on December 15, 2017, the whole content of this application being incorporated herein by reference for all purposes.

Technical Field

The present invention relates to a process for the production of perfluorinated alky lviny lethers .

Background Art

It is known that perfluorinated alkylvinylethers are an important class of monomers that are used to improve the properties of commercial polymers such as perfluorinated thermoplastics or elastomers.

Dehalogenation of a,b-dihaloperfluorinated ethers is a general method for the preparation of perfluorinated alkylvinylethers.

For example, WO 94/27945 in the name of Du Pont De Nemours and Company discloses a process for preparing perfluoroalkylvinylethers in which selected partially fluorinated compounds containing a chlorine substituted ethoxy group is fluorinated with elemental fluorine and the resulting product is dehalogenated to form the desired product. The dehalogenation reaction is carried out in aprotic dipolar solvents and in the presence of a metal or a metal containing reducing agent, for example metal Zn. In this conditions, yields in the range of 50%-68% with reaction times of 3-8 hours are described.

Houben Weil, vol E10B, part 2 (2000), “Dehalogenation”, pagg. 147-148 discloses dehalogenation reactions of a,b-dihaloperfluorinated ethers in protic or dipolar aprotic solvents in the presence of metal zinc. Reported are yields between 54% and 68% with reaction times between 2 and 7 hours.

Therefore, the above mentioned prior art processes for the production of perfluorinated alkylvinylethers are characterized by low yields and/or low reaction rates. Further, some of the known processes also necessarily require a specific solvent to be selected in a restricted group.

For example, US6388139B1 in the name of Du Pont De Nemours and Company discloses dehalogenation reactions wherein a,b-dihaloperfluoro ethers are allowed to react with metal zinc in the presence of a pyrrolidinone solvent to produce perfluoro (alkyl vinyl ethers). Specifically mentioned solvents for use in the process are N-alkyl-2-pyrrolidinones. The examples of US6388139B1 describe the preparation of CF₂=CF0CF₂CF₂S0₂F in N-methyl-2-pyrrolidinone as solvent and in the presence of bromine in function of activator of the Zinc surface, reporting yields between 68% and 82%.

Further, CN1775772 discloses a processing method for preparing perfluoro(methyl vinyl ether) from trifluoromethyl-l,l,2-trifluoro-l,2-dichloro-ethyl ether through dechlorination reaction, using dimethylformamide as solvent or adding iodine as activating agent. The solvent system described therein is meant to enable dechlorination reaction to proceed without need of zinc powder activation and solvent dehydration preprocessing.

Summary of the Invention

It is therefore an object of the present invention to provide a process for the production of perfluorinated alkylvinylethers, in high yields and at high reaction rates, that can be performed with a wide variety of solvents.

Said object is achieved with a process for producing a perfluorovinylether represented by the formula A-CR =CF-0-B, comprising the steps of :

-contacting at least one a,b-dihaloperfluoro ether represented by the formula A-CR_fX-CFX-O-B with zero valent zinc in the presence of an organic nitrogen compound selected in the group consisting of : tertiary aliphatic amines; aromatic heterocycles comprising nitrogen as heteroatom; and guanidines;

to form a mixture comprising perfluorovinylether, and

-recovering the perfluorovinylether from the mixture,

wherein :

X is selected from the group consisting of chlorine, bromine, or iodine,

R_f is fluorine or is a group of formula -OR’_f, where R’_f is selected from the group consisting of linear and branched chain perfluoroalkyl radicals;

A is selected from the group consisting of fluorine and linear and branched chain perfluoroalkyl radicals, and B is selected from the group consisting of linear and branched chain perfluoroalkyl radicals, wherein A and B can contain oxygen and sulfur heteroatoms configured in functional groups selected from ether, ester, ketone, and sulfonyl fluoride, and wherein A and B can be bonded together forming a ring.

The above defined process according to the present invention has the advantage that high reaction rates and high yields are obtainable with a large variety of common solvents, thus improving the economics and sustainability of the process.

Description of embodiments

The solvents that are useable in step A of the process of the invention are any common polar or non-polar solvents, and more preferably solvents selected from the group consisting of :

- aliphatic, cycloaliphatic and aromatic ethers, more particularly, diethyl ether, dipropyl ether, diisopropyl ether, dibutyl ether, methyltertiobutylether, dipentyl ether, diisopentyl ether, diglyme, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, dioxane, tetrahydrofuran (THF), ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, diethylene glycol mo no methyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-butyl ether; preferably aliphatic and cycloaliphatic ethers;

- glycol ether esters such as ethylene glycol methyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate,

- alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, diacetone alcohol,

- ketones such as acetone, methylethylketone (or 2-butanone), methylisobutyl ketone, diisobutylketone, cyclohexanone, isophorone;

- linear or cyclic esters such as ethyl acetate, methyl acetoacetate, dimethyl phthalate, g-butyrolactone; more preferably linear or cyclic aliphatic esters, such as ethyl acetate, methyl acetoacetate, g-butyrolactone;

- linear or cyclic carboxamides such as N,N-dimethylacetamide (DMAC), N,N-diethylacetamide, dimethylformamide (DMF), diethylformamide or N-methyl-2- pyrrolidone (NMP);

- organosulfur solvents, such as dimethyl sulfoxide (DMSO) and sulfolane (tetramethylene sulfone);

- organonitriles, such as acetonitrile, propionitrile, benzonitrile, pivalonitrile; preferably aliphatic nitriles;

Generally, step A of the process is carried out in the substantial absence of solvents qualified as Carcinogenic, Mutagenic or Toxic to Reproduction according to chemical safety classification (CMR solvents); more specifically, step A of the process is carried out in the substantial absence of NMP, DMF and DMAC.

In particular, step A of the process is advantageously carried out in the presence of at least one solvents selected in the group consisting of aliphatic and cycloaliphatic ethers; aliphatic nitriles; linear or cyclic aliphatic esters. Most preferably step A of the process is carried out in the presence of at least one solvent selected from ethyl acetate, acetonitrile, methylethylketone and dibutylether.

According to an embodiment of the process according to the present invention, X is chlorine.

According to a first embodiment of the invention, independently of the value of X, in the present invention, R_f may be fluorine, A may be fluorine and B may be a perfluorinated alkyl radical comprising one or more ether oxygen atoms and perfluorinated alkylene segments. For example, in a variant of this embodiment, R_f is fluorine, A is fluorine and B is a group of formula :

-(CF₂0)_m-(CF₂CF₂0)_n-(CF₂)_p-CF₃,

wherein m, n and p are integer numbers between 0 and 6.

In specific preferred variants, B is selected in the group consisting of the following perfluorinated radicals : -CF₃, -CF₂CF₃; -CF₂CF₂CF₃; -CF₂OCF₃;

-CF₂OCF₂CF₃; -CF₂OCF₂CF₂OCF₃.

According to a second embodiment of the invention, independently of the value ofX, in the present invention, A and B are bonded together forming a ring. For example, in a variant of this embodiment, R_f can be fluorine or can be -OR’_f, where R’_f is selected from the group consisting of linear and branched chain perfluoroalkyl radicals, and the moiety -A-B-O- is a group of formula -(0)_q(CR*c)_r-0-, with q being zero or 1, r being an integer of 1 to 3, and each of R*r, equal to or different from each other at each occurrence, being fluorine or a group of formula -OR*’_f, with R*’r being a C1-C3 perfluoroalkyl group, e.g. -CF₃.

In specific preferred variants, a,b-dihaloperfluoro ethers can be compounds of complying with formula :

ebing chlorine or bromine, preferably chlorine; and wherein each of R°_f, equal to or different from each other at each occurrence, can be fluorine or a group of formula -OR°’_f, with R°’_f being a C1-C3 perfluoroalkyl group, such as the following compounds :

with X being bromine or chlorine, preferably chlorine.

According to an embodiment of the present invention, said step a) of contacting an a,b-dihaloperfluoro ether with amounts of zero valent zinc, in the presence of an organic nitrogen compound, is carried out by using amounts of said zero valent zinc and said organic nitrogen compound that satisfy the following inequality :

M_zn/MoNc ³ 0.5

wherein M_zn is the amount in moles of zero valent zinc and M_ON_C is the amount in moles of organic nitrogen compound (ONC). Therefore, the molar ratio between the amounts of zero valent zinc and organic nitrogen compound can be higher than 0.5.

According to certain embodiments, the molar ratio between the amounts of zero valent zinc and organic nitrogen compound is of at least 0.8, so that the following inequality is satisfied :

M_zn/M_0Nc ³ 0.8, where M_zn and M_ON_C have the meaning explained above.

Upper boundary for this molar ratio is of generally at most 2, preferably at most 1.8. According to still another embodiment of the process of the invention, the ratio between the amounts in moles of zero valent zinc and organic nitrogen compound is between 0.9 and 1.6, so that the following inequality is satisfied :

0.9 > M_zn/M_0Nc ³ 1.6, where M_zn and M_ONC have the meaning explained above.

According to an embodiment of the invention, said organic nitrogen compound can be selected in the group consisting of tertiary aliphatic amines and substituted and unsubstituted pyridines.

Suitable tertiary aliphatic amines to be used in the process according to the present invention are for example : linear or cyclic aliphatic tertiary amines such as for example : trimethylamine, triethylamine, tri-isopropylamine, tributylamine, N-ethyldibutylamine, N-ethyl-N-butylamylamine, N,N-diethyl aniline, triallylamine, N,N-dipropylcyclohexylamine, N,N- dipropyloleyl-amine, N-octyldiallylamine, dicyclohexyl methyl amine, dimethylaminoethoxypropylamine,

N,N,N',N'',N''-pcntamcthyldicthylcnctriaminc, N,N-dimethylbenzylamine,

N,N-dimethylethano lamine, N,N,N,’N’ -tetramethylethy lenediamine,

N,N,N',N'-tctramcthyl- 1 ,3-propancdiaminc, N,N,N',N'- tetramethyl- 1 ,4-butanediamine, N,N,N',N'-tetramethyl- 1 ,5-pentanediamine, N,N,N',N'- tetramethyl- 1 ,6-hexanediamine, N,N-dimethylpiperazine, bis(2-dimethylaminoethyl)ether, N-substituted morpholines, such as N-methylmorpholine, N-ethylmorpholine, 2,2-dimorpholinodiethylether, 4,4'-(oxydi-2,l-ethanediyl)bismorpholine, triethy lenediamine, dimethyl cyclohexyl amine, N-cetyl N,N-dimethyl amine, N,N,N'-trimethyl-N'-hydroxy ethyl bis(aminoethyl)ether, N,N-bis(3- dimethylaminopropyl)N-isopropanolamine, 2- [2-(dimethylamino)ethoxy]ethano 1, 1 - [bis[3 -(dimethylamino)propyl]amino] -2- propanol, dimethylaminopropy lamine, bis(3-dimethylaminopropyl)amine, N,N-bis(3- (dimethylamino)propyl)-N',N'-dimethyl- 1 ,3-propanediamine, optionally susbstituted N-methylpiperidines, optionally susbstituted N-methylpiperazines, or combinations thereof.

Particularly good results have been obtained when using N,N,N,N-tetramethylethylenediamine as tertiary aliphatic amine in the process of the invention.

The expression“aromatic heterocycles comprising nitrogen as heteroatom” as used within the frame of the present invention is meant to encompass both substituted and non-substituted heterocyclic aromatic compounds, as well as mono- or polynuclear aromatic compounds, provided that these compounds possess aromatic character, and comprise at least one heterocycle whereas the heteroatom is nitrogen.

Suitable aromatic heterocycles comprising nitrogen as heteroatom comprise substituted and unsubstituted pyridines, for example alkyl- or aryl-pyridines, such as pyridines substituted in position 2-, 3- or 4- with methyl, ethyl, propyl, butyl or phenyl groups; substituted imidazoles, for example 1 -methyl, 1 -ethyl, 1 -propyl or 1 -butyl imidazole.

Suitable guanidines that can be used in the process according to the present invention are alkyl- or aryl- substituted guanidines, such as for example : N, N, N', N’-tetramethylguanidine and N,N,N',N'-tetraethylguanidine.

In the process according to the present invention, said step of contacting at least one a,b-dihaloperfluoro ether with zero valent zinc, wherein dehalogenation of said a,b-dihaloperfluoro ether takes place, can be carried out at a suitable temperature that prevents or reduces the formation of by-products. According to an embodiment of the invention, said step of contacting is carried out at a temperature between 40°C and 80°C, and preferably at a temperature between 50°C and 70°C. A preferred temperature range for carrying out said contacting step is 60±5°C.

The process according to the invention can be carried out in the absence of an activator.

Further advantages and features of the according to the present invention will become clear to those skilled in the art from the following detailed description of non limiting examples.

Comparative Example 1

In a three necked round bottom-flask equipped with magnetic stirrer, dropping funnel, thermometer and reflux condenser (-l5°C) connected to an AISI cylinder cooled in dry ice, l l.59g of Zn dust (0.177 mol), 2.07g of ZnCl₂ (0.015 mol) and 42 ml of ethyl acetate were introduced. The resulting mixture was warmed at 60°C and then 30g of CF₃OCFCICF₂CI (0.127 mol) were added dropwise recording the reaction temperature. After three hours under stirring no reaction occurred and all the starting fluorinated adduct was recovered. No reaction was obtained by increasing the temperature at 80°C, too.

Example 1A

('N,N,N,N-tctramcthylcthylcncdiaminc)

In the same equipment of Example 1 of Comparison, l l.59g of Zn dust (0.177 mol), 2.07g of ZnCl₂ (0.015 mol), 42 ml of ethyl acetate and 18.40 g of N,N,N,N-tetramethylethylenediamine (0.158 mol) were introduced. The resulting mixture was warmed at 60°C and then 30g of CF₃OCFCICF₂CI (0.127 mol) were added dropwise recording the reaction temperature. After 30’ the reaction was completed and l7.59g of raw material was condensed in the AISI cylinder. The GC analysis of the liquid phase revealed that 97% of the mixture was the desired perfluoromethylvinyl ether (CF₃OCF=CF₂).

Example 1B

(PNC = 2-mcthylpyridinc)

In the same equipment of Example 1, l l.59g of Zn dust (0.177 mol), 2.07g ofZnCl₂ (0.015 mol), 42 ml of ethyl acetate and 16.51 g of 2-methylpyridine (0.177 mol) were introduced. The resulting mixture was warmed at 60°C and then 30g of CF₃0CFClCF₂Cl (0.127 mol) were added dropwise recording the reaction temperature. After 30’ the reaction was completed and 10.75 g of raw material was condensed in the AISI cylinder. The GC analysis of the liquid phase revealed that 96% of the mixture was the desired perfluoromethylvinyl ether (CF₃0CF=CF₂).

Comparative Example 2

In the same equipment of Comparative Example 1 , 11 59g of Zn dust (0.177 mol), 2.07g of ZnCl₂ (0.015 mol) and 42 ml of acetonitrile were introduced. The resulting mixture was warmed at 60°C and then 30g of CF₃0CFClCF₂Cl (0.127 mol) were added dropwise recording the reaction temperature. After three hours under stirring no reaction occurred and all the starting fluorinated adduct was recovered. The same result was obtained by increasing temperature at 80°C.

Example 2A

(ONC=N,N,N,N-tctramcthylcthylcncdiaminc)

In the same equipment of Example 1 of Comparison, l l.59g of Zn dust (0.177 mol), 2.07g of ZnCl₂ (0.015 mol), 42 ml of acetonitrile and 18.40 g of N,N,N,N-tetramethylethylenediamine (0.158 mol) were introduced. The resulting mixture was warmed at 60°C and then 30g of CF₃OCFClCF₂Cl (0.127 mol) were added dropwise recording the reaction temperature. After 30’ the reaction was completed and 18.31 g of raw material was condensed in the AISI cylinder. The GC analysis of the liquid phase revealed that 92% of the mixture was the desired perfluoromethylvinyl ether (CF₃OCF=CF₂).

Example 2B

(ON C= 1 -methy limidazo lc)

In the same equipment of Example 1 of Comparison, l l.59g of Zn dust

(0.177 mol), 2.07g of ZnCl₂ (0.015 mol), 42 ml of acetonitrile and 14.55 g of l-methylimidazole (0.l77mol) were introduced. The resulting mixture was warmed at 60°C and then 30g of CF₃OCFClCF₂Cl (0.127 mol) were added dropwise recording the reaction temperature. After 30’ the reaction was completed and 5.78g of raw material was condensed in the AISI cylinder. The GC analysis of the liquid phase revealed that 72% of the mixture was the desired perfluoromethylvinyl ether (CF₃OCF=CF₂).

Example 2C

(PNC = N.N.N’.N’-tetramethylguanidine

In the same equipment of Example 1 of Comparison, l l.59g of Zn dust

(0.177 mol), 2.07g of ZnCl₂ (0.015 mol), 42 ml of acetonitrile and 20.53 g of

N,N,N’,N’-tctramcthylguanidinc (0.178 mol) were introduced. The resulting mixture was warmed at 60°C and then 30g of CF₃OCFClCF₂Cl (0.127 mol) were added dropwise recording the reaction temperature. After 30’ the reaction was completed and l l.52g of raw material was condensed in the AISI cylinder. The GC analysis of the liquid phase revealed that 64% of the mixture was the desired perfluoromethylvinyl ether (CF₃OCF=CF₂).

Example 2D

(PNC = 2-mcthylpyridinc)

In the same equipment of Example 1 of Comparison, l l.59g of Zn dust (0.177 mol), 2.07g of ZnCl₂ (0.015 mol), 42 ml of acetonitrile and 16.51 g of 2-methylpyridine (0.177 mol) were introduced. The resulting mixture was warmed at 60°C and then 30g of CF₃OCFClCF₂Cl (0.127 mol) were added dropwise recording the reaction temperature. After 30’ the reaction was completed and 13.01 g of raw material was condensed in the AISI cylinder. The GC analysis of the liquid phase revealed that 96% of the mixture was the desired perfluoromethylvinyl ether (CF₃0CF=CF₂).

Comparative Example 3

In the same equipment of Example 1 of Comparison, l l.59g of Zn dust

(0.177 mol), 2.07g of ZnCl₂ (0.015 mol), and 42 ml of methyl ethyl ketone were introduced. The resulting mixture was warmed at 60°C and then 30g of CF₃OCFClCF₂Cl (0.127 mol) were added dropwise recording the reaction temperature. After three hours under stirring no reaction occured and all the starting fluorinated adduct was recovered. The same result was obtained increasing temperature at 80°C.

Example 3A

(PNC = N,N,N,N-tetramethylethylenediamine)

In the same equipment of Example 1 of Comparison, l l.59g of Zn dust

(0.177 mol), 2.07g of ZnCl₂ (0.015 mol), 42 ml of methyl ethyl ketone and 18.40 g of

N,N,N,N-tetramethylethylenediamine (0.158 mol) were introduced. The resulting mixture was warmed at 60°C and then 30g of CF₃OCFClCF₂Cl (0.127 mol) were added dropwise recording the reaction temperature. After 30’ the reaction was completed and l7.59g of raw material was condensed in the AISI cylinder. The GC analysis of the liquid phase revealed that 95% of the mixture was the desired perfluoromethylvinyl ether (CF₃OCF=CF₂).

Example 3B

(OMC = N,N,N,N-tetramethylethylenediamine)

In the same equipment of Example 1 of Comparison, l l.59g of Zn dust (0.177 mol), 42 ml of methyl ethyl ketone and 18.40 g of N,N,N,N-tetramethylethylenediamine (0.158 mol) were introduced. The resulting mixture was warmed at 60°C and then 30g of CF₃OCFClCF₂Cl (0.127 mol) were added dropwise recording the reaction temperature. After 30’ the reaction was completed and 17.5 lg of raw material was condensed in the AISI cylinder. The GC analysis of the liquid phase revealed that 97% of the mixture was the desired perfluoromethylvinyl ether (CF₃OCF=CF₂).

Example 3C

(PNC = 2-mcthylpyridinc) :

In the same equipment of Example 1 of Comparison, l l.59g of Zn dust (0.177 mol), 2.07g of ZnCl₂ (0.015 mol), 42 ml of methyl ethyl ketone and 16.51 g of 2-methylpyridine (0.177 mol) were introduced. The resulting mixture was warmed at 60°C and then 30g of CF30CFClCF₂Cl (0.127 mol) were added dropwise recording the reaction temperature. After 30’ the reaction was completed and 10.80 g of raw material was condensed in the AISI cylinder. The GC analysis of the liquid phase revealed that 96% of the mixture was the desired perfluoromethylvinyl ether (CF30CF=CF₂).

Comparative Example 4

In the same equipment of Example 1 of Comparison, l l.59g of Zn dust (0.177 mol), 2.07g of ZnCl₂ (0.015 mol), and 42 ml of dibutyl ether were introduced. The resulting mixture was warmed at 80°C and then 30g of CF30CFClCF₂Cl (0.127 mol) were added dropwise recording the reaction temperature. After three hours under stirring no reaction occurred and all the starting fluorinated adduct was recovered.

Example 4A

(PNC = N,N,N,N-tetramethylethylenediamine)

In the same equipment of Example 1 of Comparison, l l.59g of Zn dust (0.177 mol), 2.07g of ZnCl₂ (0.015 mol), 42 ml of dibutyl ether and 20.61 g of N,N,N,N-tetramethylethylenediamine (0.177 mol) were introduced. The resulting mixture was warmed at 60°C and then 30g of CF3PCFClCF₂Cl (0.127 mol) were added dropwise recording the reaction temperature. After 30’ the reaction was completed and 5.38g of raw material was condensed in the AISI cylinder. The GC analysis of the liquid phase revealed that 90% of the mixture was the desired perfluoromethylvinyl ether (CF₃GCF=CF₂).

Comparative Example 5

In a three necked round bottom-flask equipped with magnetic stirrer, dropping funnel, thermometer and a Vigreux condenser connected to an AISI cylinder cooled in dry ice, l0.58g of Zn dust (0.162 mol), 1.89 g of ZnCl₂ (0.014 mol), and 42 ml of methyl ethyl ketone were introduced. The resulting mixture was warmed at 60°C under vacuum (450 mmHg, corresponding to 0.600 bar)) and then 35g of CF3OCF2OCFCICF2CI (0.116 mol) were added dropwise recording the reaction temperature. After three hours under stirring no reaction occured and all the starting fluorinated adduct was recovered. The same result was obtained increasing temperature at 80°C.

Example 5A

(PNC = N,N,N,N-tetramethylethylenediamine)

In the same equipment of Example 5 of Comparison, 4.53g of Zn dust (0.07 mol), 0.8lg of ZnCF (0.006 mol), 15 ml of methyl ethyl ketone and 7.19 g of

N,N,N,N-tetramethylethylenediamine (0.062 mol) were introduced. The resulting mixture was warmed at 60°C under vacuum (450 mmHg) and then 15 g of CF3OCF2OCFCICF2CI (0.05 mol) were added dropwise recording the reaction temperature. After 30’ the reaction was completed and l l.35g of raw material was condensed in the AISI cylinder. The GC analysis of the liquid phase revealed that 96% of the mixture was the desired vinyl ether (CF30CF₂0CF=CF₂).

Claims

1. A process for producing a perfluorovinylether represented by the formula A-CR =CF-0-B, comprising the steps of :

to form a mixture comprising perfluorovinylether, and

-recovering the perfluorovinylether from the mixture,

wherein :

X is selected from the group consisting of chlorine, bromine, or iodine,

2. A process according to the previous claim, wherein said organic nitrogen compound is selected in the group consisting of tertiary aliphatic amines, substituted and unsubstituted pyridines.

3. A process according any of the previous claims, wherein the ratio between the amounts in moles of zero valent zinc and organic nitrogen compound is higher than 0.5.

4. A process according to the previous claim, wherein the ratio between the amounts in moles of zero valent zinc and organic nitrogen compound is higher than 0.8.

5. A process according to the previous claim, wherein the ratio between the amounts in moles of zero valent zinc and organic nitrogen compound is such to satisfy the following inequality :

0.9 > Mzn/MoNC ³ 1.6

6. A process according to any of the previous claims, wherein said step of contacting at least one a,b-dihaloperfluoro ether with zero valent zinc is carried out at a temperature of from 50 to 70°C.

7. A process according to any of the previous claims, wherein R_f is fluorine, A is fluorine and B is a perfluorinated alkyl radical comprising one or more ether oxygen atoms and perfluorinated alkylene segments, and preferably wherein R_f is fluorine, A is fluorine and B is selected in the group consisting of the following perfluorinated radicals : -CF₃, -CF₂CF₃; -CF₂CF₂CF₃; -CF₂OCF₃; -CF₂OCF₂CF₃; -CF₂OCF₂CF₂OCF₃.

8. A process according to anyone of claims 1 to 7, wherein A and B are bonded together forming a ring, and wherein preferably the moiety -A-B-O- is a group of formula -(0)_q(CR*c)_r-0-, with q being zero or 1, r being an integer of 1 to 3, and each of R*_f, equal to or different from each other at each occurrence, being fluorine or a group of formula -OR*’_f, with R*’_f being a Ci-C₃ perfluoroalkyl group, e.g. -CF₃.

9. A process according to one of the previous claims, wherein X is chlorine.

10. A process according to anyone of the preceding claims, wherein the a,b-dihaloperfluoro ether is contacted with at least one amine selected from the group consisting of trimethylamine, triethylamine, tri-isopropylamine, tributylamine, N-ethyldibutylamine, N-ethyl-N-butylamylamine, N,N-diethyl aniline, triallylamine, N,N-dipropylcyclohexylamine, N,N- dipropyloleyl-amine, N-octyldiallylamine, dicyclohexyl methyl amine, dimethylaminoethoxypropylamine,

N,N,N',N'',N''-pcntamcthyldicthylcnctriaminc, N,N-dimethylbenzylamine,

N,N-dimethylethano lamine, N,N,N,’N’ -tetramethylethy lenediamine,

N,N,N',N'-tctramcthyl- 1 ,3-propancdiaminc, N,N,N',N'- tetramethyl- 1 ,4-butanediamine, N,N,N',N'-tetramethyl- 1 ,5-pentanediamine, N,N,N',N'- tetramethyl- 1 ,6-hexanediamine, N,N-dimethylpiperazine, bis(2-dimethylaminoethyl)ether, N-substituted morpholines, such as N-methylmorpholine, N- ethylmorpholine, 2,2-dimorpholinodiethylether, 4,4'-(oxydi-2,l-ethanediyl)bismorpholine, triethy lenediamine, dimethyl cyclohexyl amine, N-cetyl N,N-dimethyl amine, N,N,N'-trimethyl-N'-hydroxy ethyl bis(aminoethyl)ether, N,N-bis(3- dimethylaminopropyl)N-isopropanolamine, 2- [2-(dimethylamino)ethoxy]ethano 1, 1 - [bis[3 -(dimethylamino)propyl]amino] -2- propanol, dimethylaminopropylamine, bis(3-dimethylaminopropyl)amine,

N,N-bis(3-(dimethylamino)propyl)-N',N'-dimethyl- 1 ,3-propanediamine, optionally susbstituted N-methylpiperidines, optionally susbstituted N-methylpiperazines, or combinations thereof.

11. The process of claim 10, wherein the a,b-dihaloperfluoro ether is contacted with N,N,N,N-tetramethylethylenediamine.

12. The process of anyone of claims 1 to 10, wherein the a,b-dihaloperfluoro ether is contacted with at least one of substituted and unsubstituted pyridines, preferably selected from the group consisting of alkyl- and aryl-pyridines, such as pyridines substituted in position 2-, 3- or 4- with methyl, ethyl, propyl, butyl or phenyl groups; substituted imidazoles, for example 1 -methyl, 1 -ethyl, 1 -propyl or 1 -butyl imidazole; alkyl- or aryl- substituted guanidines, such as for example : N, N, N', N'- tetramethylguanidine and N,N,N',N'-tetraethylguanidine.

13. A process according to one of the previous claims, wherein said wherein said step of contacting at least one a,b-dihaloperfluoro ether with zero valent zinc is carried out in the presence of a solvent selected in the group consisting of ethyl acetate, acetonitrile, methylethylketone and dibutylether.