Membranes for gas separation synthesized from polyimides containing 4-fluoro-4′,4″-diaminotriphenylmethane

Patent metadata

Field	Value
Publication number	US-9675941-B2
Application number	US-201514699462-A
Country	US
Kind code	B2
Filing date	Apr 29, 2015
Priority date	Apr 30, 2014
Publication date	Jun 13, 2017
Grant date	Jun 13, 2017

Abstract

The present invention relates to the synthesis of linear aromatic polyimides and the production of membranes for the separation of gases. Specifically, polyimides featuring in their chemical structure, in the part derived from a diamine, 4-fluoro-4′,4″-diaminotriphenylmethane, and an aromatic dianhydride derived from tetracarboxylic acid. Polyimides are soluble in amidic solvents such as N,N′-dimethylformamide, N,N′-dimethylacetamide, N-methyl-2-pyrrolidone, etc., which are processed as dense membranes by controlled evaporation of the solvent. The resulting membranes are capable of separating at least a gaseous mixture constituted by two components such as H 2 /CH 4 , He/N 2 , H 2 /CO 2 , O 2 /N 2 , CO 2 /CH 4 and CO 2 /N 2 .

First claim

What is claimed is:

1. A separation membrane for gas separation comprising high molecular weight polyimides obtained from 4-fluoro-4′,4″-diaminotriphenylmethane, and having as a repeating unit the following molecular structure:

where Ar is an aromatic organic group derived from tetracarboxylic acids.

2. The separation membrane of claim 1 , wherein the tetracarboxylic acid is selected from the group consisting of 3,3′,4,4′-oxydiphthalic (ODPA), 3,3′,4,4′-benzophenontetracarboxylic (BTDA) dianhydrides, 4,4′-(hexafluoroisopropylidene)diphthalic (6FDA), and 3,3′,4,4′-biphertyltetracarboxylie (BPDA) anhydrides, a mixture of two or more of these compounds.

3. The separation membrane of claim 1 , wherein a mixture of two gases can be separated, where a component of the gaseous mixture passes through the separation membrane at a faster velocity and is separated selectively.

4. The separation membrane of claim 3 , wherein said separation membrane is adapted for separation of a gaseous mixture comprising H 2 /CH 4 .

5. The separation membrane of claim 3 , wherein said separation membrane is adapted for separation of a gaseous mixture comprising He/N 2 .

6. The separation membrane of claim 3 , wherein said said separation membrane is adapted for separation of a gaseous mixture comprising H 2 /CO 2 .

7. The separation membrane of claim 3 , wherein said separation membrane is adapted for separation of a gaseous mixture comprising O 2 /N 2 .

8. The separation membrane of claim 3 , wherein said separation membrane is adapted for separation of a gaseous mixture comprising CO 2 /CH 4 .

9. The separation membrane of claim 3 , wherein said separation membrane is adapted for separation of a gaseous mixture comprising CO 2 /N 2 .

10. The separation membrane of claim 1 , wherein Ar is selected from the group consisting of

11. A gas separation membrane adapted for separation of gases in a gas mixture, said membrane comprising a polyimide obtained from the reaction of 4-fluoro-4′,4″-diaminotriphenylmethane and an aromatic dianhydride.

12. The separation membrane of claim 11 , wherein said polyimide is obtained from the reaction of said 4-fluoro-4′,4″-diaminotriphenylmethane and where said aromatic dianhydride is selected from the group consisting of 3,3′,4,4′-oxydiphthalic (ODPA), 3,3′4,4′-benzophenontetracarboxylic (BTDA) dianhydrides, 4,4′-(hexafluoroisopropylidene)diphthalic (6FDA), and 3,3′,4,4-biphenyltetracarboxylic (BPDA) anhydrides.

13. A method of separating a gas from a gas mixture comprising the step of
passing the gas mixture through a polyimide membrane, wherein said polyimide membrane is obtained by the reaction of 4-fluoro-4′,4″-diaminotriphenylmethane and an aromatic dianhydride.

14. The method of claim 13 , wherein said polyimide has the molecular formula

where Ar is an aromatic group derived from a tetracarboxylic acid.

15. The method of claim 13 , wherein said polyimide is obtained from the reaction of said 4-fluoro-4′,4″-diarninotriphenylmethane and where said aromatic dianhydride is selected from the group consisting of 3,3′,4,4′-oxydiphthalic (ODPA), 3,3′,4,4′-benzophenontetracarboxylic (BTDA) dianhydrides, 4,4′-(hexafluoroisopropylidene)diphthalic (6FDA), and 3,3′,4,4′-biphenyltetracarboxylic (BPDA) anhydrides.

16. The method of claim 13 , wherein said gas mixture is selected from the group consisting of H 2 /CH 4 , He/N 2 , H 2 /CO 2 , O 2 /N 2 , CO 2 /CH 4 and CO 2 /N 2 .

17. The method of claim 14 , wherein Ar is selected from the group consisting of

18. A gas separation membrane comprising a polyimide obtained from 4-fluoro-4′,4″-diarninotriphenylmethane having the following structure

where said polyimide has a repeating unit with the structure

where Ar is an aromatic organic group derived from tertacarboxylic acids.

Assignees

• Mexicano Inst Petrol

Inventors

• Guzman Lucero Diego Javier
• Guzman Pantoja Javier
• Palomeque Santiago Jorge Froylan

Classifications

• B01D2256/24

  Hydrocarbons · CPC title

• C08G73/1053

  with oxygen only in the tetracarboxylic moiety · CPC title

• Y02C10/10

  Cross-Sectional Technologies · mapped topic

• B01D67/0009

  by phase separation, sol-gel transition, evaporation or solvent quenching · CPC title

• B01D2256/16

  Hydrogen · CPC title