Abstract: A method for removing ethylene from the atmosphere surrounding an agricultural product that is sensitive to ethylene, which promotes climacteric ripening and senescence, is disclosed. The method uses a membrane for selective ethylene permeation and removal from a container that is used to store, transport, and preserve the agricultural product.

Abstract: This invention discloses a method for separation of an aromatic compound from a mixture comprising an alkane using an improved thin-film composite membrane. The membrane is particularly useful for separation of benzene from cyclohexane, which have similar boiling points. The membrane comprises a more mechanically durable and defect-free separation layer as a result of its fabrication from an ionomer solution that is substantially free of dissolved ionic species not associated with the ionomer.

Abstract: This invention discloses a thin-film composite membrane and process for the separation of carbon dioxide from non-hydrophilic gases such as methane, hydrogen, and nitrogen. The thin-film composite membrane has a gas-separation layer and a nonporous high-diffusion-rate layer, and has carbon dioxide to non-hydrophilic gas selectivity that is greater than the intrinsic selectivity of the gas-separation layer alone.

Abstract: This invention discloses a method for separation of an aromatic compound from a mixture comprising an alkane using an improved thin-film composite membrane. The membrane is particularly useful for separation of benzene from cyclohexane, which have similar boiling points. The membrane comprises a more mechanically durable and defect-free separation layer as a result of its fabrication from an ionomer solution that is substantially free of dissolved ionic species not associated with the ionomer.

Abstract: Membranes having a permselective active layer of a copolymerized perfluorinated monomer and an non-fluorinated alkylvinylester monomer demonstrate superior selective permeability performance for separating gas mixtures compared to membranes of exclusively perfluorinated polymers. Preferred active layer compositions are copolymers of perfluoro-2,2-dimethyl-1,3 dioxole (PDD) copolymerized with an alkylvinyl ester such as vinyl acetate, and vinyl pivalate, and with alkylvinyl esters that are substantially hydrolyzed to provide copolymerized vinyl alcohol functionality. The membranes can have a thin, high diffusion rate, “gutter layer” of a fluorinated polymer highly permeable to nitrogen positioned between the active layer and a porous support layer. A novel copolymer effective in selectively permeable membranes is a copolymer of PDD and an alkylvinyl ester compound having the formula H2C?CHOC(O)R1 in which R1 is a linear or branched alkyl group of from 2 to 5 carbon atoms.

Abstract: Composite membranes comprised of at least two layers, one of the layers being a silver ionomer and a second layer which is a fluorinated polymer with certain permeability properties, are especially useful for the separation of alkanes from alkenes, Particularly useful is a three-layer composite membrane in which a porous layer is laminated to the second layer.

Abstract: A metal exchanged fluorinated ionomer is a copolymer minimally including repeating units of (i) a polymerized derivative of a perfluorinated cyclic or cyclizable monomer and (ii) a strong acid highly fluorinated vinylether compound in which the acid moiety is exchanged with a cation of a Group 11 metal. Metal exchanged fluorinated ionomers are readily soluble and can be formed into thin, selectively gas permeable membranes by solution deposition methods. These membranes are suitable for separating olefins from gas olefin/paraffin mixtures. Good selectivity and transmembrane flux can be obtained without humidifying the membrane feed gas mixture.

Abstract: Membranes having a permselective active layer of a copolymerized perfluorinated monomer and an non-fluorinated alkylvinylester monomer demonstrate superior selective permeability performance for separating gas mixtures compared to membranes of exclusively perfluorinated polymers. Preferred active layer compositions are copolymers of perfluoro-2,2-dimethyl-1,3 dioxole (PDD) copolymerized with an alkylvinyl ester such as vinyl acetate, and vinyl pivalate, and with alkylvinyl esters that are substantially hydrolyzed to provide copolymerized vinyl alcohol functionality. The membranes can have a thin, high diffusion rate, “gutter layer” of a fluorinated polymer highly permeable to nitrogen positioned between the active layer and a porous support layer. A novel copolymer effective in selectively permeable membranes is a copolymer of PDD and an alkylvinyl ester compound having the formula H2C?CHOC(0)R1 in which R1 is a linear or branched alkyl group of from 2 to 5 carbon atoms.

Abstract: Composite membranes comprised of at least two layers, one of the layers being a silver ionomer and a second layer which is a fluorinated polymer with certain permeability properties, are especially useful for the separation of alkanes from alkenes, Particularly useful is a three-layer composite membrane in which a porous layer is laminated to the second layer.

Abstract: Described herein are copolymers derived from certain perfluorinated sulfonyl fluoride monomers, cyclic or cyclizable perfluorinated monomers, and one or both of ethylene and/or vinyl fluoride. Group 11 metal sulfonate ionomers of these copolymers, especially silver ionomers, are useful in membranes which separate olefins from alkanes.

Abstract: Ionomers of Group 11 metals which include repeat units from vinylidene fluoride, can separate alkenes from alkanes when comprising a layer of a membrane. These membranes have excellent permeability and/or selectivity for alkenes in the separation of alkenes from alkanes.

Abstract: A highly fluorinated polymer is very useful as an acid catalyst. The highly fluorinated polymer has at least two repeating unit types that are the polymerized derivatives of a perfluorinated cyclic or cyclizable compound and a highly fluorinated vinyl ether compound having a sulfur containing functional group. The polymer can be formed by radical copolymerization of the fluorinated monomers with the sulfur-containing functional group in sulfonyl fluoride form (—SO2F) that is subsequently converted to sulfonic acid form (—SO3H). The highly fluorinated polymer can be used to advantage in a solution comprising an aprotic, polar organic solvent that has a dielectric constant of at least 15 and preferably is free of hydroxyl functional groups. Suitable solvents are those in which the polymer is soluble to at least 1 wt %. Hydroxyl group-containing protic, polar organic solvents are less preferred.

Abstract: A highly fluorinated polymer is very useful as an acid catalyst. The highly fluorinated polymer has at least two repeating unit types that are the polymerized derivatives of a perfluorinated cyclic or cyclizable compound and a highly fluorinated vinyl ether compound having a sulfur containing functional group. The polymer can be formed by radical copolymerization of the fluorinated monomers with the sulfur-containing functional group in sulfonyl fluoride form (—SO2F) that is subsequently converted to sulfonic acid form (—SO3H). The highly fluorinated polymer can be used to advantage in a solution comprising an aprotic, polar organic solvent that has a dielectric constant of at least 15 and preferably is free of hydroxyl functional groups. Suitable solvents are those in which the polymer is soluble to at least 1 wt %. Hydroxyl group-containing protic, polar organic solvents are less preferred.