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 8,221,531 B2
• Filed: 12/31/2007
• Issued: 07/17/2012
• Est. Priority Date: 12/31/2007
• Status: Expired due to Fees

• Current Assignee: Chevron USA Incorporated (Chevron Corp.)
• Original Assignee: Chevron USA Incorporated (Chevron Corp.)
• Inventors: Wind, John D., Miller, Stephen J., Okeowo, Oluwasijibomi O.
• Primary Examiner(s): Greene, Jason M
• Assistant Examiner(s): SHUMATE, ANTHONY R
• Application Number:
  US11/968,080
• Publication Number:
  US 20090165645A1
• Time in Patent Office: 1,660 Days
• Field of Search: 96/4, 96/6, 96/10, 95/43, 95/45, 95/51
• US Class Current: 96/10
• 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 also are described.

Claims

1. A crosslinked polyimide membrane comprising:

a polyimide membrane for gas separation having crosslinked chains of polyimides which contain organic titanate, wherein the organic titanate is present at less than 50 parts per million by weight of the membrane.

2. The crosslinked membrane of claim 1 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 catalyst into the monoesterified membrane.

3. The membrane of claim 2 wherein:

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

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

4. The membrane of claim 2 wherein:

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

5. The membrane of claim 4:

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

6. The membrane of claim 5 wherein:

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

the organic titanate catalyst is imbibed into the membrane.

7. The membrane of claim 2 wherein:

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

8. The membrane of claim 2 wherein:

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

9. The membrane of claim 2 wherein:

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

10. The membrane of claim 2 wherein:

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

C.

11. The membrane of claim 2 wherein:

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

C.

12. The membrane of claim 2 wherein:

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

C.

13. The membrane of claim 2, wherein:

the organic titanate catalyst is an alkyl titanate.

14. The membrane of claim 2, wherein:

the organic titanate catalyst is a titanium chelate.

15. The membrane of claim 1 wherein:

the membrane is a flat sheet.

16. The crosslinked polyimide membrane of claim 1 comprising:

a polyimide membrane having crosslinked chains of polyimides which contain organic titanate, wherein the organic titanate is present at less than 30 parts per million by weight.

17. The crosslinked polyimide membrane of claim 1 comprising:

a polyimide membrane having crosslinked chains of polyimides which contain organic titanate, wherein the organic titanate is present at less than 20 parts per million by weight.

18. The crosslinked polyimide membrane of claim 1 comprising:

a polyimide membrane having crosslinked chains of polyimides which contain organic titanate, wherein the organic titanate is present at less than 10 parts per million by weight.

19. The crosslinked polyimide membrane of claim 1 wherein:

the organic titanate is tetra-isopropoxide titanate.