US4959082A — Polycarbonate gas separation membranes containing…

Claim 1

Independent Claim 202 words

A process for separating gases using a semi-permeable gas separation membrane comprising: A. contacting one side of a semi-permeable membrane with a feed gas mixture under pressure, wherein the membrane divides a separation chamber into a high pressure side into which the feed gas mixture is fed and a low pressure side; B. maintaining a pressure differential across the membrane under conditions such that at least one component of the gas mixture selectively permeates through the membrane from the high pressure side to the low pressure side of the membrane; C. removing from the low pressure side of the membrane permeated gas which is enriched in at least one faster permeating component of the gas mixture; and D. removing from the high pressure side of the membrane non-permeated gas which is depleted in at least one faster permeating component of the gas mixture; wherein the membrane comprises a thin discriminating layer of a polycarbonate gas separation membrane containing at least one substituted benzene in an amount effective to interact with the polycarbonate polymer and increase the gas flux and/or gas selectivity of the membrane by at least about 10 percent without causing a significant decrease in the tensile strength of the membrane.

Claim 2

Dependent Claim 202 words

A process for separating gases using a semi-permeable gas separation membrane comprising: A. contacting one side of a semi-permeable membrane with a feed gas mixture under pressure, wherein the membrane divides a separation chamber into a high pressure side into which the feed gas mixture is fed and a low pressure side; B. maintaining a pressure differential across the membrane under conditions such that at least one component of the gas mixture selectively permeates through the membrane from the high pressure side to the low pressure side of the membrane; C. removing from the low pressure side of the membrane permeated gas which is enriched in at least one faster permeating component of the gas mixture; and D. removing from the high pressure side of the membrane non-permeated gas which is depleted in at least one faster permeating component of the gas mixture; wherein the membrane comprises a thin discriminating layer of a polycarbonate gas separation membrane containing at least one substituted benzene in an amount effective to interact with the polycarbonate polymer and increase the gas flux and/or gas selectivity of the membrane by at least about 10 percent without causing a significant decrease in the tensile strength of the membrane.

Claim 3

Dependent Claim 36 words

The process of claim 1 wherein the feed gas contains at least one gas selected from the group consisting of hydrogen, helium, oxygen, nitrogen, carbon monoxide, carbon dioxide, hydrogen sulfide, water vapor, ammonia, and/or light hydrocarbons.

Claim 4

Dependent Claim 18 words

The process of claim 2 wherein the feed gas pressure is between about 25 and about 1,000 psig.

Claim 5

Dependent Claim 18 words

The process of claim 3 wherein the feed gas temperature is between about 5° and about 150° C.

Claim 6

Dependent Claim 59 words

A semi-permeable gas separation membrane comprising a thin discriminating layer of a polycarbonate polymer containing at least one substituted benzene in an amount effective to interact with the polycarbonate polymer and increase the gas flux and/or gas selectivity of the membrane by at least about 10 percent without causing a significant decrease in the tensile strength of the membrane.

Claim 7

Dependent Claim 59 words

A semi-permeable gas separation membrane comprising a thin discriminating layer of a polycarbonate polymer containing at least one substituted benzene in an amount effective to interact with the polycarbonate polymer and increase the gas flux and/or gas selectivity of the membrane by at least about 10 percent without causing a significant decrease in the tensile strength of the membrane.

Claim 8

Dependent Claim 82 words

The membrane of claim 5 wherein the polycarbonate is comprised of backbone units corresponding to the formula: ##STR5## wherein R is independently in each occurrence --CO--, --S--, --SO 2 --, --O--, a C 1-6 divalent hydrocarbon radical, an inertly substituted C 1-6 divalent hydrocarbon radical, or a C 1-6 divalent halocarbon radical; X is independently in each occurrence hydrogen, a halogen, a C 1-4 alkyl, or a C 1-4 haloalkyl; and n is a positive real number of about 20 or greater.

Claim 9

Dependent Claim 61 words

The membrane of claim 6 wherein the substituted benzene possesses a boiling point of at least about 100° C. and corresponds to the formula: ##STR6## wherein R 1 is independently in each occurrence hydrogen, hydroxy, a halogen, a C 1-4 alkyl, a C 1-4 haloalkyl, a C 1-4 alkoxy, or nitro, and m is an integer between 1 and 6, inclusive.

Claim 10

Dependent Claim 22 words

The membrane of claim 7 wherein R is a C1-6 divalent hydrocarbon radical; and X is hydrogen, chlorine, bromine, fluorine, or methyl.

Claim 11

Dependent Claim 22 words

The membrane of claim 8 wherein at least about 25 percent of the bisphenol residues present in the polycarbonate backbone are tetra-substituted.

Claim 12

Dependent Claim 20 words

The membrane of claim 9 wherein the membrane contains between about 10 and about 20,000 ppm of the substituted benzene(s).

Claim 13

Dependent Claim 13 words

The membrane of claim 10 wherein the polycarbonate membrane is asymmetric or composite.

Claim 14

Dependent Claim 12 words

The membrane of claim 11 wherein the membrane is a hollow fiber.

Claim 15

Dependent Claim 10 words

The membrane of claim 12 wherein the polycarbonate is 2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane.

Claim 16

Dependent Claim 20 words

The membrane of claim 13 wherein the polycarbonate membrane possesses a separation factor for oxygen/nitrogen of at least about 5.5.

Claim 17

Dependent Claim 18 words

The membrane of claim 14 wherein the polycarbonate membrane possesses an oxygen flux of at least about ##EQU10##

Claim 18

Dependent Claim 86 words

A process for fabricating a semi-permeable gas separation membrane comprising the steps of: A. contacting at least one side of a semipermeable polycarbonate gas separation membrane with treatment fluid containing at least one substituted benzene under conditions such that an effective amount of the substituted benzene(s) is absorbed into the membrane and interacts with the polycarbonate polymer to increase the gas flux and/or gas selectivity of the membrane by at least about 10 percent without causing a significant decrease in the tensile strength of the membrane.

Claim 19

Dependent Claim 86 words

A process for fabricating a semi-permeable gas separation membrane comprising the steps of: A. contacting at least one side of a semipermeable polycarbonate gas separation membrane with treatment fluid containing at least one substituted benzene under conditions such that an effective amount of the substituted benzene(s) is absorbed into the membrane and interacts with the polycarbonate polymer to increase the gas flux and/or gas selectivity of the membrane by at least about 10 percent without causing a significant decrease in the tensile strength of the membrane.

Claim 20

Dependent Claim 80 words

The process of claim 16 wherein the polycarbonate comprises a polymer corresponding to the formula: ##STR7## wherein R is independently in each occurrence --CO--, --S--, --SO 2 --, --O--, a C 1-6 divalent hydrocarbon radical, an inertly substituted C 1-6 divalent hydrocarbon radical, or a C 1-6 divalent halocarbon radical; X is independently in each occurrence hydrogen, a halogen, a C 1-4 alkyl, or a C 1-4 haloalkyl; and n is a positive real number of about 20 or greater.

Claim 21

Dependent Claim 61 words

The process of claim 17 wherein the substituted benzene possesses a boiling point of at least about 100° C. and corresponds to the formula: ##STR8## wherein R 1 is independently in each occurrence hydrogen, hydroxy, a halogen, a C 1-4 alkyl, a C 1-4 haloalkyl, a C 1-4 alkoxy, or nitro and m is an integer between 1 and 6, inclusive.

Claim 22

Dependent Claim 11 words

The process of claim 18 wherein the treatment fluid comprises water.

Claim 23

Dependent Claim 64 words

The process of claim 19 comprising the further step of: B. contacting at least one side of the membrane with air, an inert gas, a vacuum, or a combination thereof under conditions such that substantially all of the water is removed from the membrane while the membrane retains an effective amount of the substituted benzene(s) without deleteriously affecting the physical integrity of the membrane.

Claim 24

Dependent Claim 24 words

The process of claim 20 wherein the substituted benzene(s) is present in the aqueous solution in an amount between about 50 and 10,000 ppmv.

Claim 25

Dependent Claim 17 words

The process of claim 21 wherein the treatment temperature is between about 5° and about 60° C.

Claim 26

Dependent Claim 12 words

The process of claim 18 wherein the treatment fluid is a vapor.

Claim 27

Dependent Claim 24 words

The process of claim 23 wherein the substituted benzene(s) is present in the vapor in an amount between about 50 and about 10,000 ppmv.

Claim 28

Dependent Claim 17 words

The process of claim 24 wherein the treatment temperature is between about 5° and about 90° C.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1993-09-24	1994-03-26	1994-09-25	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1997-09-24	1998-03-26	1998-09-25	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2001-09-24	2002-03-26	2002-09-25	$7700.00	Window Closed / Lapsed

Polycarbonate gas separation membranes containing substituted benzenes and processes for making and using the same

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