Claims
- 1. A process for separating one or more gases from a mixture of gases comprising the steps of bringing said gaseous mixture into contact with a first side of a gas separation membrane such that a portion of said gas mixture permeates to a second side of said membrane and a portion of said gas mixture is collected as a nonpermeate, the resulting gas mixture on said second side of said membrane being enriched in one or more components over that of the mixture on the first side of said membrane, wherein said gas separation membrane is formed from a sulfonated polyimide comprising repeating units of the formula: ##STR5## is selected from the group consisting of: ##STR6## or mixtures thereof; --Ar.sub.2 -- is an aromatic sulfonated diamine moiety selected from the group consisting of: ##STR7## or mixtures thereof; --Ar.sub.3 -- is an aromatic diamine moiety selected from the group consisting of: ##STR8## or mixtures thereof; R.sub.1 is hydrogen, --SO.sub.3 H, --SO.sub.3 M or --SO.sub.2 OR.sub.2, wherein at least one R.sub.1 in the Ar.sub.2 aromatic diamine moiety is --SO.sub.3 H, --SO.sub.3 M or --SO.sub.2 OR.sub.2 ;
- R.sub.2 is either an aryl radical or an alkyl radical with less than 6 carbon atoms;
- M is an organic base, ammonium ion, alkali metal ion, alkali-earth metal ion, or transitional metal ion;
- Q is one of hydrogen, --CH.sub.3 or --C.sub.2 H.sub.5 when Ar.sub.2 is ##STR9## Q is one of --CH.sub.3 or --C.sub.2 H.sub.5 when Ar.sub.2 is ##STR10## Y is selected from the group consisting of hydrogen, --CH.sub.3, --C(CH.sub.3).sub.3, --CF.sub.3, --F, --Cl, --Br, or --I;
- Z is selected from the group consisting of: ##STR11## R.sub.3 is an aliphatic radical; t equals 1 to 6;
- n is a fraction from 0.01 to 1 and
- m is a fraction from 0 to 1.0.
- 2. The process of claim 1 wherein Ar.sub.2 is selected from the group consisting of: 4,4'-diaminostilbene-2,2'-disulfonic acid, 4,4'-diaminobiphenyl-2,2'-disulfonic acid, 4,4'-diamino-3,3'-dimethylbiphenyl-6,6'-disulfonic acid, 2,4-diaminobenzene sulfonic acid, their respective salt forms or mixtures thereof.
- 3. The process of claim 2 wherein Ar.sub.3 is selected from the group consisting of 2,4,6-trimethyl-1,3-phenylenediamine, 2,6-diaminotoluene, 3,3'-diaminodiphenyl sulfone, 1,5-diaminonaphthalene, 2,2-bis (4-aminophenyl) hexafluoropropane, o-tolidine sulfone, or mixtures thereof.
- 4. The process of claim 1 wherein n is a fraction from 0.1 to 0.7 and m is a fraction from 0.5 to 1.0.
- 5. The process of claim 4 wherein Ar.sub.1 is 2,2-(3,4-dicarboxyphenyl) hexafluoropropane dianhydride.
- 6. The process of claim 5 wherein Ar.sub.2 is 4,4'-diaminostilbene-2,2'-disulfonic acid lithium salt and Ar.sub.3 is 1,5-diaminonaphthalene.
- 7. The process of claim 6 wherein M is a lithium ion.
- 8. The process according to claim 1, wherein R.sub.2 is either a methyl or ethyl radical.
- 9. The process of claim 1, wherein R.sub.3 is either --CH.sub.3 or --C.sub.2 H.sub.5.
- 10. The process of claim 1 wherein said membrane is a composite gas separation membrane.
- 11. The process of claim 10 wherein the said composite membrane was prepared by coating a porous substrate with a sulfonated polyimide dissolved in a solvent selected from the group consisting of: ethyl acetate, ethylene glycol monomethyl ether, methyl alcohol, ethyl alcohol, isopropanol or mixtures thereof.
- 12. The process of claim 1 wherein said membrane is an asymmetric gas separation membrane.
- 13. The process of claim 1 wherein said membrane is a hollow fiber membrane.
- 14. The process of claim 1 wherein M is a lithium ion.
- 15. The process of claim 1 wherein said sulfonated polyimide was prepared by a method comprising:
- (a) dissolving a mixture of sulfonated and unsulfonated aromatic diamines in a polar solvent;
- (b) adding dianhydride to the reaction mixture;
- (c) forming polyamic acid via polycondensation reaction;
- (d) chemically converting said polyamic acid into sulfonated polyimide; and
- (e) recovering said sulfonated polyimide.
- 16. The process of claim 15 wherein said polar solvent is dimethylsulfoxide.
- 17. The process of claim 1 wherein said gas mixture comprises at least one of CO.sub.2 or H.sub.2 S.
- 18. A sulfonated polyimide comprising repeating units of the formula: ##STR12## is selected from the group consisting of: ##STR13## or mixtures thereof; --Ar.sub.2 -- is an aromatic sulfonated diamine moiety selected from the group consisting of: ##STR14## or mixtures thereof; --Ar.sub.3 -- is an aromatic diamine moiety selected from the group consisting of: ##STR15## or mixtures thereof; R.sub.1 is hydrogen, --SO.sub.3 H, --SO.sub.3 M or --SO.sub.2 OR.sub.2, wherein at least one R.sub.1 in the Ar.sub.2 aromatic diamine moiety is --SO.sub.3 H, --SO.sub.3 M Or --SO.sub.2 OR.sub.2 ;
- R.sub.2 is either an aryl radical or an alkyl radical with less than 6 carbon atoms;
- M is an organic base, ammonium ion, alkali metal ion, alkali-earth metal ion, or transitional metal ion;
- Q is one of hydrogen, --CH.sub.3 or --C.sub.2 H.sub.5 when Ar.sub.2 is ##STR16## Q is one of --CH.sub.3 or --C.sub.2 H.sub.5 when Ar.sub.2 is ##STR17## Y is selected from the group consisting of hydrogen, --CH.sub.3, --C(CH.sub.3).sub.3, --CF.sub.3, --F, --Cl, --Br, or --I;
- Z is selected from the group consisting of: ##STR18## R.sub.3 is an aliphatic radical; t equals 1 to 6;
- n is a fraction from 0.01 to 1 and
- m is a fraction from 0 to 1.0.
- 19. The sulfonated polyimide of claim 18 wherein Ar.sub.2 is selected from the group consisting of: 4,4'-diaminostilbene-2,2'-disulfonic acid, 4,4'-diaminobiphenyl-2,2'-disulfonic acid, 4,4'-diamino-3,3'-dimethylbiphenyl-6,6'-disulfonic acid, 2,4-diaminobenzene sulfonic acid, their respective salt forms or mixtures thereof.
- 20. The sulfonated polyimide of claim 19 wherein Ar.sub.3 is selected from the group consisting of 2,4,6-trimethyl-1,3-phenylenediamine, 2,6-diaminotoluene, 3,3'-diaminodiphenyl sulfone, 1,5-diaminonaphthalene, 2,2-bis(4-aminophenyl) hexafluoropropane, o-tolidine sulfone, or mixtures thereof.
- 21. The sulfonated polyimide of claim 18 wherein Ar.sub.1 is 2,2-(3,4-dicarboxyphenyl) hexafluoropropane dianhydride.
Parent Case Info
This is a Continuation-in-Part of prior U.S. application Ser. No. 08/497,655 filing Date: Jun. 30, 1995, now U.S. Pat. No. 5,618,334.
US Referenced Citations (40)
Foreign Referenced Citations (3)
Number |
Date |
Country |
0179474 |
Apr 1986 |
EPX |
57-159505 |
Oct 1982 |
JPX |
58-037024 |
Mar 1983 |
JPX |
Non-Patent Literature Citations (4)
Entry |
E. Gilbert, Sulfonation and Related Reactions; 1977, pp. 1-121. |
H. Cerfontain, Mechanistic Aspects in Aromatic Sulfonation and Desulfonation; 1968, Ch. 1-4, 6, 7 and 9. |
Yu.E. Kirsch et al., Journal of Membrane Science 103, 95-103; (1995). |
Synthesis and Properties of Sulphonated Polypyromellitimides--Vasil,eva, et al., Polymer Science, USSR, pp. 160-168 (Received 26 Jun. 1970). |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
497655 |
Jun 1995 |
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