Provided are a novel compound, 1,1,1,5,5,5-hexafluoro-3-(2,2,2-trifluoroethoxy)-2-pentene, and uses thereof and a method for producing this novel compound. According to the present invention, 1,1,1,5,5,5-hexafluoro-3-(2,2,2-trifluoroethoxy)-2-pentene is provided. This novel compound can be produced, for example, by reacting 1,1,1,5,5,5-hexafluoro-3-chloro-2-pentene with 2,2,2-trifluoroethanol in the presence of a base. This novel compound is also useful as an additive in a nonaqueous electrolytic solution for a secondary battery.

Provided are a novel compound, 1,1,1,5,5,5-hexafluoro-3-(2,2,2-trifluoroethoxy)-2-pentene, and uses thereof and a method for producing this novel compound. According to the present invention, 1,1,1,5,5,5-hexafluoro-3-(2,2,2-trifluoroethoxy)-2-pentene is provided. This novel compound can be produced, for example, by reacting 1,1,1,5,5,5-hexafluoro-3-chloro-2-pentene with 2,2,2-trifluoroethanol in the presence of a base. This novel compound is also useful as an additive in a nonaqueous electrolytic solution for a secondary battery.

A method for producing a composition including a step A of performing ultrafiltration, microfiltration, dialysis membrane treatment, or a combination thereof on a composition containing water and a fluoropolymer. The fluoropolymer is a polymer having a structural unit M3 derived from a monomer represented by general formula (1):
CX.sub.2CY(CZ.sub.2ORf-A)(1)
where X is the same or different and is H or F; Y is H, F, an alkyl group, or a fluorine-containing alkyl group; Z is the same or different and is H, F, an alkyl group, or a fluoroalkyl group; Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms or a fluorine-containing alkylene group having 2 to 100 carbon atoms and having an ether bond; and A is COOM, SO.sub.3M, OSO.sub.3M, or C(CF.sub.3).sub.2OM, wherein M is as defined herein; provided that at least one of X, Y, and Z includes a fluorine atom.

A method for producing a composition including a step A of performing ultrafiltration, microfiltration, dialysis membrane treatment, or a combination thereof on a composition containing water and a fluoropolymer. The fluoropolymer is a polymer having a structural unit M3 derived from a monomer represented by general formula (1):
CX.sub.2CY(CZ.sub.2ORf-A)(1)
where X is the same or different and is H or F; Y is H, F, an alkyl group, or a fluorine-containing alkyl group; Z is the same or different and is H, F, an alkyl group, or a fluoroalkyl group; Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms or a fluorine-containing alkylene group having 2 to 100 carbon atoms and having an ether bond; and A is COOM, SO.sub.3M, OSO.sub.3M, or C(CF.sub.3).sub.2OM, wherein M is as defined herein; provided that at least one of X, Y, and Z includes a fluorine atom.

An aim of the present disclosure is to provide a method for producing a fluoroalkoxide, said method being more useful than conventional methods, and the like. The aim can be achieved by a method for producing a compound represented by the following formula (1):

##STR00001## (wherein R.sup.1 is a fluoroalkyl group optionally containing an oxygen atom between carbon atoms, or a fluoroalkoxy group optionally containing an oxygen atom between carbon atoms, and each R.sup.2 is identical to or different from each other and is a hydrocarbon group), the method comprising the step of reacting a compound represented by the following formula (2):

##STR00002## with a compound represented by the following formula (3):

##STR00003##

An aim of the present disclosure is to provide a method for producing a fluoroalkoxide, said method being more useful than conventional methods, and the like. The aim can be achieved by a method for producing a compound represented by the following formula (1):

##STR00001## (wherein R.sup.1 is a fluoroalkyl group optionally containing an oxygen atom between carbon atoms, or a fluoroalkoxy group optionally containing an oxygen atom between carbon atoms, and each R.sup.2 is identical to or different from each other and is a hydrocarbon group), the method comprising the step of reacting a compound represented by the following formula (2):

##STR00002## with a compound represented by the following formula (3):

##STR00003##

A method for making a halo (alkyl vinyl) ether comprising heating a reaction mixture comprising a combination of i) a metal; ii) a solvent; and iii) a halo (alkyl ethyl) ether according to formula (1) RCF.sub.2OC(H)(X)CF.sub.2Y (1) where R is independently H, F, Cl, Br, CF.sub.2H, CF.sub.3, CF.sub.2CF.sub.2H, linear perfluoroalkyl having 1 to 12 carbon atoms, or cyclic perfluoroalkyl having 1 to 12 carbon atoms, and X and Y are independently Cl, Br, I, or F, where X and Y are not both F; to form a reaction product mixture comprising a halo (alkyl vinyl) ether, the solvent, unreacted metal, and a metal salt.

A method for making a halo (alkyl vinyl) ether comprising heating a reaction mixture comprising a combination of i) a metal; ii) a solvent; and iii) a halo (alkyl ethyl) ether according to formula (1) RCF.sub.2OC(H)(X)CF.sub.2Y (1) where R is independently H, F, Cl, Br, CF.sub.2H, CF.sub.3, CF.sub.2CF.sub.2H, linear perfluoroalkyl having 1 to 12 carbon atoms, or cyclic perfluoroalkyl having 1 to 12 carbon atoms, and X and Y are independently Cl, Br, I, or F, where X and Y are not both F; to form a reaction product mixture comprising a halo (alkyl vinyl) ether, the solvent, unreacted metal, and a metal salt.

The present disclosure aims to provide a composition comprising a fluorine-containing monomer and fluoride ions wherein the amount of fluoride ions mixed in the fluorine-containing monomer is small, a method for producing a fluorine-containing monomer having a further reduced fluoride ion content from a fluorine-containing monomer contaminated with fluoride ions, a method for purifying a fluorine-containing monomer contaminated with fluoride ions, and the like. The present disclosure relates to a composition comprising a fluorine-containing monomer (M) and fluoride ions, wherein the fluoride ion content is 0.01 to 1000 ppm by mass based on the mass of the composition, and the fluorine-containing monomer (M) is at least one monomer selected from the group consisting of a compound represented by formula (M1), a compound represented by formula (M2), and a compound represented by formula (M3):

##STR00001##

wherein R.sup.1 to R.sup.10 each independently represent a fluorine atom, a perfluoroalkyl group, or a perfluoroalkoxy group.

The present disclosure aims to provide a composition comprising a fluorine-containing monomer and fluoride ions wherein the amount of fluoride ions mixed in the fluorine-containing monomer is small, a method for producing a fluorine-containing monomer having a further reduced fluoride ion content from a fluorine-containing monomer contaminated with fluoride ions, a method for purifying a fluorine-containing monomer contaminated with fluoride ions, and the like. The present disclosure relates to a composition comprising a fluorine-containing monomer (M) and fluoride ions, wherein the fluoride ion content is 0.01 to 1000 ppm by mass based on the mass of the composition, and the fluorine-containing monomer (M) is at least one monomer selected from the group consisting of a compound represented by formula (M1), a compound represented by formula (M2), and a compound represented by formula (M3):

##STR00001##

wherein R.sup.1 to R.sup.10 each independently represent a fluorine atom, a perfluoroalkyl group, or a perfluoroalkoxy group.