CROSSLINKED POLYIMIDE MEMBRANE, METHOD FOR MAKING THE SAME USING ORGANIC TITANATE CATALYSTS TO FACILITATE CROSSLINKING AND METHOD OF USING THE MEMBRANE FOR FLUID SEPARATION

• US 20090165645A1
• Filed: 12/31/2007
• Published: 07/02/2009
• Est. Priority Date: 12/31/2007
• Status: Active Grant

• Current Assignee: Chevron USA Incorporated (Chevron Corp.)
• Original Assignee: Chevron USA Incorporated (Chevron Corp.)
• Inventors: Wind, John D., Okeowo, Oluwasijibomi O., Miller, Stephen J.
• Granted Patent: US 8,221,531 B2
• Time in Patent Office: Days
• US Class Current: 95/51
• CPC Class Codes: B01D 2257/504 Carbon dioxide
• CPC Class Codes: B01D 2323/30 Cross-linking
• CPC Class Codes: B01D 53/22 by diffusion manufacturing semi-permeable membranes B01D67/00; form, structure or properties of semi-permeable membranes B01D69/00; material for semi-permeable membranes B01D71/00
• CPC Class Codes: B01D 69/145 containing embedded catalysts
• CPC Class Codes: B01D 71/64 Polyimides; Polyamide-imides; Polyester-imides; Polyamide acids or similar polyimide precursors
• CPC Class Codes: C08G 73/1039 comprising halogen-containing substituents
• CPC Class Codes: C08G 73/1042 Copolyimides derived from at least two different tetracarboxylic compounds or two different diamino compounds
• CPC Class Codes: C08G 73/1067 Wholly aromatic polyimides, i.e. having both tetracarboxylic and diamino moieties aromatically bound
• CPC Class Codes: C08L 79/08 Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
• CPC Class Codes: Y02C 20/40 of CO2
• CPC Class Codes: Y02P 20/151 Reduction of greenhouse gas [GHG] emissions, e.g. CO2

Abstract

A method of making a crosslinked polyimide membrane is described. A monoesterified membrane is formed from a monoesterified polyimide polymer. The monoesterified membrane is subjected to transesterification conditions to form a crosslinked membrane. The monoesterified membrane is incorporated with an organic titanate catalyst before or after formation of the monoesterified membrane. A crosslinked polyimide membrane made using the aforementioned method and a method of using the membrane to separate fluids in a fluid mixture, such as methane and carbon dioxide, are also disclosed.

Claims

1. A method of making a crosslinked polyimide membrane, comprising:

(a) forming a monoesterified membrane from a monoesterified polyimide polymer, and

(b) subjecting the monoesterified membrane to transesterification conditions to form a crosslinked fiber membrane;

wherein the forming of the monoesterified membrane includes incorporating an organic titanate catalyst into the monoesterified membrane.

2. The method of claim 1 wherein:

the monoesterified polyimide polymer and the organic titanate catalyst are placed together in a solution and then the monesterified membrane is formed.

3. The method of claim 1 wherein:

the monoesterified polyimide membrane is formed and then the organic titanate catalyst is imbibed into the monoesterified polyimide membrane.

4. The method of claim 3:

the monoesterified polyimide polymer is spun into a hollow fiber membrane and then the organic titanate catalyst is imbibed into the hollow fiber membrane.

5. The method of claim 4 wherein:

the organic titanate catalyst is dissolved in a solution which maintains the morphology of the membrane; and

the organic titanate catalyst is imbibed into the membrane.

6. The method of claim 1 wherein:

the monoesterified membrane is heated for less than 24 hours to form the crosslinked membrane.

7. The method of claim 1 wherein:

the monoesterified membrane is heated for less than 12 hours to form the crosslinked fiber membrane.

8. The method of claim 1 wherein:

the monoesterified membrane is heated for than 6 hours to form the crosslinked fiber membrane.

9. The method of claim 1 wherein:

the transesterification conditions include heating the membrane at between 50-200°

C.

10. The method of claim 1 wherein:

the transesterification conditions include heating the membrane at between 75-150°

C.

11. The method of claim 1 wherein:

the transesterification conditions include heating the membrane at less than 150°

C.

12. The method of claim 1, wherein:

the organic titanate catalyst is an alkyl titanate.

13. The method of claim 12, wherein:

the alkyl titanate catalyst is Tyzor®

TPT catalyst.

14. The method of claim 1, wherein:

the organic titanate catalyst is Tyzor®

TE catalyst.

15. The method of claim 1, wherein:

the organic titanate catalyst is a titanium chelate.

16. The method of claim 15, wherein:

the organic titanate catalyst is Vertec™

VEXP0504.

20. A method of using the crosslinked fiber membrane made according to the method of claim 1, comprising:

(a) providing a feed stream selected from the group consisting of air, a mixture of methane and nitrogen, a mixture of methane and hydrogen, a refinery stream, a mixture of carbon dioxide and methane, and syngas, the feed stream including a gaseous component selected from the group consisting of nitrogen, oxygen, hydrogen, and carbon dioxide;

(b) maintaining a pressure differential between an upstream side of the membrane and a downstream side of the membrane;

(c) contacting the upstream side of the membrane with the feed stream at a pressure between about 20 psia and about 4000 psia;

(d) isolating a permeate stream on the downstream side of the membrane having a larger mole fraction of the faster permeating component than the feed stream; and

(e) isolating a retentate stream having a smaller mole fraction of the faster permeating component than the feed stream.

21. The method of claim 20, wherein:

the feed stream comprises carbon dioxide and methane and the gaseous component is carbon dioxide.

22. The method of claim 1 wherein:

the organic titanate catalyst is Tyzor®

TPT and is present at a concentration of less than 100 ppmw.

17. A crosslinked polyimide membrane comprising:

a polyimide membrane having crosslinked chains of polyimides which contain organic titanate.

18. The crosslinked membrane of claim 17 wherein the membrane is made by the steps of:

(a) forming a monoesterified membrane from a monoesterified polyimide polymer, and

(b) subjecting the monoesterified membrane to transesterification conditions to form a crosslinked fiber membrane;

wherein the forming of the monesterified membrane includes incorporating an organic titanate catalysts into the monoesterified membrane.

19. The membrane of claim 18 wherein:

the monoesterified membrane is formed into a hollow fiber membrane; and

then the organic titanate catalyst is imbibed into the hollow fiber membrane.