Semipermeable membranes prepared from polymers containing pendent sulfone groups

• US 4,427,419 A
• Filed: 03/12/1982
• Issued: 01/24/1984
• Est. Priority Date: 03/12/1982
• Status: Expired due to Fees

• Current Assignee: Standard Oil Company (BP PLC)
• Original Assignee: Standard Oil Company (BP PLC)
• Inventors: Li, George S.
• Primary Examiner(s): Spitzer, Robert H.
• Application Number:
  US06/357,366
• Time in Patent Office: 683 Days
• Field of Search: 55/16, 55/68, 55/158, 210/500.2
• US Class Current: 95/51
• CPC Class Codes: B01D 71/50 Polycarbonates
• CPC Class Codes: B01D 71/5223 Polyphenylene oxide, phenyl ether polymers or polyphenylethers
• CPC Class Codes: B01D 71/66 Polymers having sulfur in the main chain, with or without nitrogen, oxygen or carbon only
• CPC Class Codes: C07C 7/144 using membranes, e.g. selective permeation
• CPC Class Codes: C07C 9/04 Methane production by treatment of sewage C02F11/04; natural gas, synthetic natural gas C10L3/06
• CPC Class Codes: Y02C 20/40 of CO2

Abstract

Semipermeable membranes useful for separating gaseous mixtures of carbon dioxide and methane into enriched fractions of each are prepared from at least one polymer containing a preponderance of arylene units, such as polyxylene oxide, the arylene units containing pendent sulfone groups substituted with an aromatic group, such as phenyl.

Claims

1. A semipermeable membrane useful for separating a gaseous mixture of CO₂ and CH₄ into enriched fractions of each, the membrane formed from at least one polymer containing a preponderance of arylene units of the formula ##STR7## where each R is independently a C₁ -C₈ aliphatic or a C₅ -C₇ cycloaliphatic hydrocarbon radical, an aryl radical, an aralkyl radical or an alkaryl radical, each radical being free of a tertiary α

-carbon atom;

each Q is a radical of the formula ##STR8## where R'"'"' is a nonpolymeric aryl radical;

X is a divalent oxygen or sulfur atom or a carbonate group;

m is an integer of 0-2; and

n is 0-1 with the proviso that n is 1 in at least 10 percent of the arylene units of the polymer.

2. The membrane of claim 1 where R'"'"' is an aryl radical of the formula ##STR9## where each R" is independently a C₁ -C₆ aliphatic radical, and

p is an integer of 0-4.

3. The membrane of claim 2 where R'"'"' is selected from the group consisting of phenyl, tolyl, xyleneyl and phenethyl.

4. The membrane of claim 3 wherein n=1 in at least 20 percent of the arylene units of the polymer.

5. The membrane of claim 4 where x is a divalent oxygen atom.

6. The membrane of claim 5 where each R is independently a C₁ -C₄ alkyl radical.

7. The membrane of claim 5 where m is 0.

8. The membrane of claim 7 where at least one of the polymers used to form the membrane consists essentially of repeating units of I.

9. The membrane of claim 8 formed from essentially only the polymer consisting essentially of repeating units of I.

10. A process of separating a gaseous mixture of CO₂ and CH₄ into enriched fractions of each, the process comprising contacting the mixture with one side of the membrane of claim 1 in such a manner that the CO₂ portion of the mixture is selectively passed through the membrane while the CH₄ portion of the mixture is selectively rejected by the membrane.