Cross-Linkable and Cross-Linked Mixed Matrix Membranes and Methods of Making the Same

• US 20090031897A1
• Filed: 08/19/2008
• Published: 02/05/2009
• Est. Priority Date: 12/15/2005
• Status: Active Grant

• Current Assignee: Chunqing Liu, Jeffrey J. Chiou, Stephen T. Wilson
• Original Assignee: Chunqing Liu, Jeffrey J. Chiou, Stephen T. Wilson
• Inventors: Liu, Chunqing, Wilson, Stephen T., Chiou, Jeffrey J.
• Granted Patent: US 7,806,962 B2
• Time in Patent Office: Days
• US Class Current: 95/45
• CPC Class Codes: B01D 2323/30 Cross-linking
• CPC Class Codes: B01D 2323/345 UV-treatment
• CPC Class Codes: B01D 53/228 characterised by specific membranes
• CPC Class Codes: B01D 67/0004 by agglomeration of particles
• CPC Class Codes: B01D 67/009 with wave-energy, particle-radiation or plasma
• CPC Class Codes: B01D 69/02 characterised by their properties
• CPC Class Codes: B01D 69/1411 containing dispersed material in a continuous matrix
• CPC Class Codes: B01D 71/64 Polyimides; Polyamide-imides; Polyester-imides; Polyamide acids or similar polyimide precursors
• CPC Class Codes: Y02C 20/20 of methane
• CPC Class Codes: Y02C 20/40 of CO2
• CPC Class Codes: Y10S 55/05 Methods of making filter

Abstract

The present invention is for novel high performance cross-linkable and cross-linked mixed matrix membranes and the use of such membranes for separations such as for CO₂/CH₄, H₂/CH₄ and propylene/propane separations. More specifically, the invention involves the preparation of cross-linkable and cross-linked mixed matrix membranes (MMMs). The cross-linkable MMMs were prepared by incorporating microporous molecular sieves or soluble high surface area microporous polymers (PIMs) as dispersed microporous fillers into a continuous cross-linkable polymer matrix. The cross-linked MMMs were prepared by UV-cross-linking the cross-linkable MMMs containing cross-linkable polymer matrix such as BP-55 polyimide. Pure gas permeation test results demonstrated that both types of MMMs exhibited higher performance for CO₂/CH₄ and H₂/CH₄ separations than those of the corresponding cross-linkable and cross-linked pure polymer matrices.

Claims

1. A process for separating at least one gas from a mixture of gases, the process comprising:

a) providing a mixed matrix membrane comprising a UV-cross-linkable or UV-cross-linked polymer as a continuous phase and microporous molecular sieves dispersed in the continuous phase wherein said mixed matrix membrane is permeable to said at least one gas;

b) contacting the mixture of gases to a first side of the mixed matrix membrane to cause said at least one gas to permeate the mixed matrix membrane; and

c) removing from a second side of the membrane a permeate gas composition comprising at least a portion of said at least one gas which permeated said membrane.

2. The process of claim 1 wherein said mixed matrix membrane has been exposed to ultraviolet radiation for a sufficient period of time to cause said UV-cross-linkable polymer to be cross-linked.

3. The process of claim 1 wherein said molecular sieves are selected from the group consisting of SAPO-34, Si-DDR, AlPO-14, AlPO-34, AlPO-18, LTA, ERS-12, NaA (4A), CaA (5A), KA (3A), CDS-1, SSZ-62, UZM-9, UZM-13, UZM-17, UZM-19, MCM-65, MCM-47, silicalite-1, Si-MTW, UZM-8, SAPO-31, EU-1, ZSM-57, NU-87, Si-BEA, Si-MEL, FAU, OFF, zeolite L, NaX, NaY, and CaY molecular sieves.

4. The process of claim 1 wherein said UV-cross-linkable polymer is a UV-cross-linkable rigid, glassy polymer.

5. The process of claim 4 wherein said UV-cross-linkable rigid, glassy polymer is selected from the group consisting of benzophenone, acrylic, vinyl, styrenic, styrenic-acrylic, sulfonic, and 2,3-dihydrofuran containing polymers.

6. The process of claim 4 wherein said UV-cross-linkable polymer is selected from the group consisting of polyacrylates;

polyimides;

poly(styrenes), styrene-containing copolymers;

polysulfone; and

polyethersulfone.

7. The process of claim 1 wherein said mixture of gases comprises a pair of gases selected from the group consisting of carbon dioxide/natural gas, hydrogen/methane, carbon dioxide/nitrogen, methane/nitrogen, iso/normal paraffins and olefins/paraffins.

8. The process of claim 2 wherein said UV-cross-linkable polymer is exposed to UV light for a period of time between about 5 to 30 minutes.

9. A mixed matrix membrane comprising a UV-cross-linkable or UV-cross-linked continuous phase organic polymer and microporous molecular sieves dispersed in said cross-linkable or cross-linked continuous phase organic polymer.

10. The mixed matrix membrane of claim 9 wherein said molecular sieves are selected from the group consisting of SAPO-34, Si-DDR, AlPO-14, AlPO-34, AlPO-18, LTA, ERS-12, NaA (4A), CaA (5A), KA (3A), CDS-1, SSZ-62, UZM-9, UZM-13, UZM-17, UZM-19, MCM-65, MCM-47, silicalite-1, Si-MTW, UZM-8, SAPO-31, EU-1, ZSM-57, NU-87, Si-BEA, Si-MEL, FAU, OFF, zeolite L, NaX, NaY, and CaY molecular sieves.

11. The mixed matrix membrane of claim 9 wherein said UV-cross-linkable polymer is selected from the group consisting of benzophenone, acrylic, vinyl, styrenic, styrenic-acrylic, sulfonic, and 2,3-dihydrofuran containing polymers.

12. The mixed matrix membrane of claim 9 wherein said UV-cross-linkable polymer is selected from the group consisting of polyacrylates;

polyimides;

poly(styrenes), styrene-containing copolymers;

polysulfone; and

polyethersulfone.

13. The mixed matrix membrane of claim 9 wherein said mixed matrix membrane has a geometry selected from the group consisting of sheets, hollow fibers and tubes.

14. A method of making a mixed matrix membrane comprising:

providing a UV-cross-linkable continuous phase organic polymer;

providing microporous molecular sieves;

dispersing the microporous molecular sieves into a solution containing the continuous phase organic polymer;

allowing the continuous phase organic polymer to solidify about the microporous molecular sieves to produce a mixed matrix membrane; and

exposing said continuous phase organic polymer to UV radiation for a sufficient period of time to cross-link said continuous phase organic polymer.

15. The method of claim 14 wherein said UV-cross-linkable continuous phase organic polymer is selected from the group consisting of benzophenone, acrylic, vinyl, styrenic, styrenic-acrylic, sulfonic, and 2,3-dihydrofuran containing polymers.

16. The method of claim 14 wherein said UV-cross-linkable continuous phase organic polymer is selected from the group consisting of polyacrylates;

polyimides;

poly(styrenes), styrene-containing copolymers;

polysulfone; and

polyethersulfone.

17. The method of claim 14 wherein said microporous molecular sieves are selected from the group consisting of SAPO-34, Si-DDR, AlPO-14, AlPO-34, AlPO-18, LTA, ERS-12, NaA (4A), CaA (5A), KA (3A), CDS-1, SSZ-62, UZM-9, UZM-13, UZM-17, UZM-19, MCM-65, MCM-47, silicalite-1, Si-MTW, UZM-8, SAPO-31, EU-1, ZSM-57, NU-87, Si-BEA, Si-MEL, FAU, OFF, zeolite L, NaX, NaY, and CaY molecular sieves.