Claims
- 1. A process for separating carbon dioxide from an unsaturated fluorinated compound carbon dioxide mixture comprising one or more stages in which a feed stream of said unsaturated fluorinated compound carbon dioxide mixture is contacted with a semipermeable membrane to form at least one exit stream having an increased concentration of carbon dioxide and at least one exit stream having a reduced concentration of carbon dioxide, said process in at least one of said one or more stages causing said exit stream with increased concentration of carbon dioxide to contain less than about 5% by weight of the unsaturated fluorinated compound present in said feed stream.
- 2. The process of claim 1 wherein said unsaturated fluorinated compound comprises a compound of the formula R--CF.dbd.CF.sub.2, wherein R is F, Cl, R.sub.f or O--Rf and R.sub.f is perfluoroalkyl containing 1-5 carbon atoms.
- 3. The process of claim 1 wherein said unsaturated fluorinated compound comprises tetrafluoroethylene.
- 4. The process of claim 1 wherein said semipermeable membrane comprises a membrane selected from the group consisting of polyimide membranes and polyaramid membranes.
- 5. The process of claim 1 wherein said semipermeable membrane comprises a polyimide membrane having phenylindane residues incorporated in the polyimide backbone chain.
RELATED APPLICATIONS
This application claims the benefit of U.S. Provisional Application No. 60/045,440 filed May 2, 1997.
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Non-Patent Literature Citations (2)
Entry |
Membranes can Efficiently Separate CO.sub.2 From Mixtures, Schell et al., Oil & Gas Journal, Aug. 15, 1983, p. 83. |
Relationship Between Gas Separation Properties and Chemical Structure in a Series of Aromatic Polyimides, Kim et al., Journal of Membrane Science, 37 (1988), 45-62. |