Chemically and UV cross-linked high selectivity polyimide membranes for gas separations

Patent metadata

Field	Value
Publication number	US-10427110-B2
Application number	US-201715798346-A
Country	US
Kind code	B2
Filing date	Oct 30, 2017
Priority date	Jun 25, 2015
Publication date	Oct 1, 2019
Grant date	Oct 1, 2019

Abstract

This invention discloses a membrane composition, a method of making, and applications for a new type of high selectivity, high plasticization-resistant and solvent-resistant, both chemically and UV cross-linked polyimide membranes. Gas permeation tests on these membranes demonstrated that they not only showed high selectivities, but also showed extremely high CO 2 plasticization resistance under CO 2 pressure up to 4923 kPa (700 psig). This new type of high selectivity, high plasticization-resistant and solvent-resistant, both chemically and UV cross-linked polyimide membranes can be used for a wide range of gas separations such as separations of H 2 /CH 4 , He/CH 4 , CO 2 /CH 4 , CO 2 /N 2 , olefin/paraffin separations (e.g. propylene/propane separation), O 2 /N 2 , iso/normal paraffins, polar molecules such as H 2 O, H 2 S, and NH 3 mixtures with CH 4 , N 2 , H 2 , and other light gases separations. The membranes can also be used for liquid separations such as in the removal of organic compounds from water.

First claim

The invention claimed is:

1. A polymer comprising a plurality of repeating units of formula (I):

wherein X 1 is selected from the group consisting of

and mixtures thereof; wherein X 2 is selected from the group consisting of

and mixtures thereof; Y 1 is selected from the group consisting of

and mixtures thereof; Y 2 is selected from the group consisting of

and mixtures thereof, and —R 1 is selected from the group consisting of

and mixtures thereof, and —R 2 is selected from the group consisting of
—CH 3 , —C 2 H 5

and —R 3 is selected from the group consisting of

and mixtures thereof; n and m are independent integers from 2 to 500; the molar ratio of n/m is in a range of 1:10 to 10:1.

2. The polyimide polymer of claim 1 wherein X 1 and X 2 are the same and are

3. The polyimide polymer of claim 1 wherein Y 1 is

4. The polyimide polymer of claim 1 wherein Y 2 is

and —R 1 is selected from the group consisting of

5. A polyimide polymer membrane comprising the polyimide polymer of claim 1 .

6. The polyimide polymer membrane of claim 5 is chemically and UV cross-linked.

7. The polyimide polymer membrane of claim 5 comprising a thin nonporous selective separation layer formed from the polyimide polymer with a plurality of repeating units of formula (I) and a porous nonselective mechanical support layer made from a material different from the polyimide polymer with a plurality of repeating units of formula (I).

8. The polyimide polymer membrane of claim 7 wherein said thin nonporous selective separation layer formed from the polyimide polymer with a plurality of repeating units of formula (I) is chemically and UV cross-linked.

9. The polyimide polymer membrane of claim 7 wherein said material different from the polyimide polymer with a plurality of repeating units of formula (I) is selected from the group consisting of polysulfones, sulfonated polysulfones, polyethersulfones (PESs), sulfonated PESs, polyethers, polyetherimides, cellulosic polymers, polyamides, polyimides, polyether ketones, and blends thereof.

10. A method of making a chemically and UV cross-linked polyimide membrane comprising: 1) preparing a casting solution of a polyimide polymer with a plurality of repeating units of a formula (I):

wherein X 1 is selected from the group consisting of

and mixtures thereof, wherein X 2 is selected from the group consisting of

and mixtures thereof; Y 1 is selected from the group consisting of

and mixtures thereof; Y 2 is selected from the group consisting of

and mixtures thereof, and —R 1 is selected from the group consisting of

and mixtures thereof, and —R 2 is selected from the group consisting of
—CH 3 , —C 2 H 5

and —R 3 is selected from the group consisting of

and mixtures thereof; n and m are independent integers from 2 to 500; the molar ratio of n/m is in a range of 1:10 to 10:1 by: a) dissolving 3-isocyanatopropyltrialkyloxysilane and a polyimide polymer with a plurality of repeating units of formula (II)

wherein X 1 is selected from the group consisting of

and mixtures thereof; wherein X 2 is selected from the group consisting of

and mixtures thereof; Y 1 is selected from the group consisting of

and mixtures thereof; Y 3 is selected from the group consisting of

and mixtures thereof, and —R 4 is selected from the group consisting of —H, —COCH 3 , and mixtures thereof, and —R 5 is selected from the group consisting of

and mixtures thereof; n and m are independent integers from 2 to 500; the molar ratio of n/m is in a range of 1:10 to 10 in an organic solvent to form a homogeneous solution; b) heating said homogeneous solution for 4-8 hours at 40-70° C. to form said solution of the polyimide polymer via a reaction between 3-isocyanatopropyltrialkyloxysilane and said polyimide polymer with a plurality of repeating units of formula (II); 2) casting said casting solution of the polyimide polymer with a plurality of repeating units of formula (I) on a membrane substrate or on a polymeric cloth substrate or on a clean glass plate to form a thin layer of said casting solution of the polyimide polymer with a plurality of repeating units of formula (I); 3) removing the organic solvents from the thin layer of said casting solution of the polyimide polymer to form a flat sheet membrane; 4) drying the membrane to form chemically cross-linked polyimide membrane comprising the polyimide polymer with a plurality of repeating units of formula (I) wherein the trialkyloxysilane groups have reacted with each other and have formed covalent bonds among the polymer chains; 5) coating said dried membrane with a thin layer of high permeability material; and 6) UV cross-linking said coated and dried membrane via UV radiation to cross-link the membrane via covalent bonds between the UV cross-linkable sulfonyl or carbonyl group and methyl group on said new polyimide polymer chains with a plurality of repeating units of formula (I).

11. The method of claim 10 wherein the organic solvent is selected from the group consisting of N-methyl-2-pyrrolidone, 1,3-dioxolane, tetrahydrofuran,

Assignees

• Uop Llc

Inventors

• Liu Chunqing
• Tran Howie Q

Classifications

• C08G73/10

  Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors · CPC title

• B01D2323/30

  Cross-linking · CPC title

• C10L3/103

  Sulfur containing contaminants · CPC title

• B01D2323/345

  UV-treatment · CPC title

• C10G31/00

  Refining of hydrocarbon oils, in the absence of hydrogen, by methods not otherwise provided for (by distillation C10G7/00) · CPC title