Use of silver-exchanged ionomer membranes for gas separation
First Claim
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1. In a process for separating at least one alkene containing 2 to 4 carbon atoms per molecule from at least one alkane containing 1 to 6 carbon atoms per molecule contained in a gaseous feed by means of an ionomer membrane, the improvements which comprise:
- having water vapor present in said gaseous feed, andusing a silver-exchanged ionomer membrane having been prepared by the preparation method comprising the steps of(a) contacting (i) an ionomer membrane of a copolymer of tetrafluoroethylene and at least one perfluorovinyl ether containing a terminal sulfonic acid group with (ii) a solution of at least one alkali metal compound, under such conditions as to obtain an alkali-metal-exchanged ionomer membrane;
(b) contacting the thus-obtained alkali-metal-exchanged ionomer membrane with a liquid comprising at least one alcohol containing from 2 to 20 carbon atoms and from 1 to 5 hydroxyl groups per molecule, under such conditions as to obtain a swollen alkali-metal-exchanged ionomer membrane; and
(c) treating the thus-obtained swollen alkali-metal-exchanged ionomer membrane with a solution containing at least one silver compound, under such conditions as to replace alkali metal ions with silver ions in said ionomer membrane.
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Abstract
A process for separating C2 -C4 alkenes from C1 -C6 alkanes comprises the presence of water vapor in the alkene/alkane feed and the use of an Ag+ -exchanged sulfonated copolymer of tetrafluoroethylene and perfluorovinyl ether having been prepared by one of several specific ion-exchange methods.
36 Citations
51 Claims
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1. In a process for separating at least one alkene containing 2 to 4 carbon atoms per molecule from at least one alkane containing 1 to 6 carbon atoms per molecule contained in a gaseous feed by means of an ionomer membrane, the improvements which comprise:
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having water vapor present in said gaseous feed, and using a silver-exchanged ionomer membrane having been prepared by the preparation method comprising the steps of (a) contacting (i) an ionomer membrane of a copolymer of tetrafluoroethylene and at least one perfluorovinyl ether containing a terminal sulfonic acid group with (ii) a solution of at least one alkali metal compound, under such conditions as to obtain an alkali-metal-exchanged ionomer membrane; (b) contacting the thus-obtained alkali-metal-exchanged ionomer membrane with a liquid comprising at least one alcohol containing from 2 to 20 carbon atoms and from 1 to 5 hydroxyl groups per molecule, under such conditions as to obtain a swollen alkali-metal-exchanged ionomer membrane; and (c) treating the thus-obtained swollen alkali-metal-exchanged ionomer membrane with a solution containing at least one silver compound, under such conditions as to replace alkali metal ions with silver ions in said ionomer membrane. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. In a process for separating at least one alkene containing 2 to 4 carbon atoms per molecule from at least one alkane containing 1 to 6 carbon atoms per molecule contained in a gaseous feed by means of an ionomer membrane, the improvements comprise:
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having water vapor present in said gaseous feed, and using a silver-exchanged ionomer membrane having been prepared by the preparation method consisting essentially of the steps of (A) contacting (i) an ionomer membrane of a copolymer of tetrafluoroethylene and a perfluorovinyl ether containing a terminal sulfonic acid group with (ii) a solution consisting essentially of at least one alkali metal and water, under such conditions as to obtain an alkali-metal-exchanged ionomer membrane, and (B) treating the alkali-metal exchanged ionomer membrane obtained in step (A) with a solution consisting essentially of at least one silver compound and water, under such conditions as to obtain a substantially silver-exchanged ionomer membrane. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23)
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24. In a process for separating at least one alkene containing 2 to 4 carbon atoms per molecule from at least one alkane containing 1 to 6 carbon atoms per molecule contained in a gaseous feed by means of an ionomer membrane, the improvements comprise:
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having water vapor present in said gaseous feed, and using a silver-exchanged ionomer membrane having been prepared by the preparation process consisting essentially of the steps of (1) mixing (α
) a solution of a copolymer of tetrafluoroethylene and a perfluorovinyl ether containing a terminal sulfonic acid group and (β
) at least one silver compound, under such conditions to obtain a solution comprising a silver-exchanged copolymer;(2) coating a porous support material with the solution obtained in step (1); and (3) removing solvent contained in the solution used in step (2) from the coated porous support material obtained in step (2). - View Dependent Claims (25, 26, 27, 28, 29, 30, 31, 32, 33)
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34. In a process for separating at least one alkene containing 2 to about 4 carbon atoms per molecule from at least one alkane containing 1 to 6 carbon atoms per molecule contained in a gaseous feed by means of an ionomer membrane, the improvements which comprise:
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having water vapor present in said gaseous feed, and using a silver-exchanged ionomer membrane having been prepared by the preparation method comprising the steps of (a) contacting (i) an ionomer membrane of a copolymer of tetrafluoroethylene and at least one perfluorovinyl ether containing a terminal sulfonic acid group with (ii) a solution of at least one alkali metal compound, under such conditions as to obtain an alkali-metal-exchanged ionomer membrane; (b) contacting the thus-obtained alkali-metal-exchanged ionomer membrane with a liquid comprising at least one alcohol containing from 2 to 20 carbon atoms and from 1 to 5 hydroxyl groups per molecule, under such conditions as to obtain a swollen alkali-metal-exchanged ionomer membrane; (b1) separating the swollen alkali-metal-exchanged ionomer membrane obtained in step (b) from said at least one alcohol used in step (b); (b2) immersing the separated swollen alkali-metal-exchanged ionomer membrane obtained in step (b1) in water or, alternatively, in an aqueous solution of an alkali metal compound, for a period of time in the range of about 0.5 day to about 50 days; and (c) treating the swollen alkali-metal-exchanged ionomer membrane having undergone the treatment of step (b2) with a solution containing at least one silver compound, under such conditions as to replace alkali metal ions with silver ions in said ionomer membrane. - View Dependent Claims (35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51)
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Specification