Manufacturing carbon molecular sieve membranes using a pyrolysis atmosphere comprising sulfur-containing compounds

Patent metadata

Field	Value
Publication number	US-2016184775-A1
Application number	US-201514972980-A
Country	US
Kind code	A1
Filing date	Dec 17, 2015
Priority date	Dec 31, 2014
Publication date	Jun 30, 2016
Grant date	—

Abstract

A carbon molecular sieve (CMS) membrane is made by pyrolyzing a polymeric precursor membrane in a pyrolysis atmosphere containing a sulfur-containing compound.

First claim

What is claimed is:

1 . A method for producing a CMS membrane, comprising the steps of:
forming a polymeric precursor membrane; and pyrolyzing the polymeric precursor membrane in a pyrolysis atmosphere containing 5 ppm (vol/vol) to 50% (vol/vol) of an sulfur-containing compound in a balance of inert gas.

2 . The method of claim 1 , wherein the sulfur-containing compound is selected from the group consisting of H 2 S, H 2 SO 4 , COS, SO 2 , SO 3 , CS 2 , SeS 2 , Se 2 S 6 , S, SF 6 , and benzyl disulfide.

3 . The method of claim 1 , wherein the balance gas is N 2 , Ar or mixtures thereof.

4 . The method of claim 1 , wherein the polymeric precursor membrane comprises a separation layer, the separation layer comprising 6FDA:BPDA/DAM.

5 . The method of claim 1 , wherein the pyrolysis is conducted at a pressure of 0.25-1.0 bar (abs).

6 . The method of claim 1 , wherein the polymeric precursor membrane comprises a polyimide comprising alternating units of diamine-derived units and of dianhydride-derived units having the structure of formula I,

wherein:
each R 1 is a molecular segment independently selected from the group consisting of formula (A), formula (B), formula (C), and formula (D):

Z is a molecular segment independently selected from the group consisting of formula (e), formula (f), formula (g), (h), (i), (j), and (k):

the R 2 's are molecular segments independently selected from the group consisting of formula (i), formula (ii), formula (iii), formula (iv), formula (v), formula (vi), formula (vii), formula (viii), formula (ix), formula (x), formula (xi), formula (xii), formula (xiii), formula (xiv), formula (xv), formula (xvi) and formula (xviii):

each X 5 is independently selected from the group consisting of hydrogen, —Cl, —OCH 3 , —OCH 2 CH 3 , and a straight or branched C 1 to C 6 alkyl group;
R a is a straight or branched C 1 to C 6 alkyl group having a terminal carboxylic acid group;
each Z′ is a molecular segment independently selected from the group consisting of the molecular segment of formula (xvii), formula (xviii), formula (xix), formula (xx), formula (xxi), formula (xxii), formula (xxiii), formula (xxiv), formula (xxv), formula (xxvi), formula (xxvii), formula (xxviii), formula (xxix), formula (xxxi), formula (xxxii), formula (xxxiii), formula (xxxiv), formula (xxxv), formula (xxxvi), formula (xxxvii), formula (xxxviii), formula (xxxix), and formula (xl):

subscript p is an integer from 1-10; and
each Z″ is a molecular segment independently selected from the group consisting of the molecular segment of formula (xxvii), formula (xxviii), and formula (xl).

7 . A CMS membrane produced according to the method of claim 1 .

8 . A method for separating a gas mixture, comprising the steps of feeding the gas mixture to the CMS membrane of claim 7 , withdrawing a permeate gas from a permeate outlet of the CMS membrane, and withdrawing a non-permeate gas from a non-permeate outlet of the CMS membrane that is deficient in at least one gas relative to the gas mixture.

Assignees

• Air Liquide

Inventors

• Chevrel Henri
• Jurcik Jr Benjamin J
• Coignet Philippe A
• Swaidan Raja
• Kratzer Dean W

Classifications

• B01D53/228

  characterised by specific membranes · CPC title

• B01D71/021

  Carbon · CPC title

• B01D67/0067 Primary

  by carbonisation or pyrolysis · CPC title

• B01D2256/16

  Hydrogen · CPC title

• B01D2256/245

  Methane · CPC title