Patent US4812238A successfully refreshed from Google Patents.
US4812238A
Expired / Lapsed
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Membranes prepared via reaction of diazonium compounds or precursors
Assignee: Filmtec Corp
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Filing: 1987-08-10
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Granted: 1989-03-14
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Expires: 2007-08-10
Abstract
Abstract An improved reverse osmosis membrane and process for making the same is described. The membrane is prepared by treating a polymer bearing primary amine groups with nitrous acid or a diazonium compound so as to react the resulting diazonium groups with other groups present. The resulting membrane possesses improved chlorine resistance. When the nitrous acid treatment is employed, the water flux of a polyamide membrane is frequently increased with little or no effect on the salt rejection of the membrane.
Inventors
- 👤 John E. Cadotte
- 👤 Donald L. Schmidt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 04:11
CPC Classifications
B; B01; B01D; B01D67/00; B01D67/0081; B01D67/0093; B01D69/00; B01D69/12; B01D69/125; B01D69/1251; B01D71/00; B01D71/06; B01D71/56; B01D2323/00; B01D2323/30
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
48 words
A semi-permeable membrane comprising a discriminating layer derived from a polymer including an average of at least one primary amine group or salt thereof and at least one group reactive with a diazonium salt by reacting the polymer with a diazonium salt or precursor of a diazonium salt.
Claim 2
Dependent Claim
48 words
A semi-permeable membrane comprising a discriminating layer derived from a polymer including an average of at least one primary amine group or salt thereof and at least one group reactive with a diazonium salt by reacting the polymer with a diazonium salt or precursor of a diazonium salt.
Claim 3
Dependent Claim
69 words
The membrane as described in claim 1 wherein the membrane is a composite reverse osmosis membrane and the polymer is a polyamide derived from reactants comprising (a) a compound or polymer bearing an average of at least two primary amine groups and (b) a compound or polymer bearing an average of at least two carboxylic acid halide groups and the polyamide bears a plurality of residual aromatic amine groups.
Claim 4
Dependent Claim
20 words
The membrane as described in claim 2 wherein (b) is an aromatic compound bearing at least two acid halide groups.
Claim 5
Dependent Claim
20 words
The membrane as described in claim 2 wherein (b) is a trimesoyl halide, isophthaloyl halide, terephthaloyl halide or mixtures thereof.
Claim 6
Dependent Claim
18 words
The membrane as described in claim 4 wherein (b) consists of at least 50 mole percent trimesoyl chloride.
Claim 7
Dependent Claim
11 words
The membrane as described in claim 4 wherein (a) is meta-phenylenediamine.
Claim 8
Dependent Claim
30 words
The membrane as described in claim 4 wherein (a) is an aromatic polyamine prepared by reaction of a difunctional aromatic primary amine and trimellitic anhydride acid halide or trimesoyl halide.
Claim 9
Dependent Claim
12 words
The membrane as described in claim 2 wherein (b) is cyclohexane-1,3,5-tricarbonyl chloride.
Claim 10
Dependent Claim
11 words
The membrane as described in claim 8 wherein (a) is meta-phenylenediamine.
Claim 11
Dependent Claim
12 words
The membrane as described in claim 2 wherein (a) is a phenylenediamine.
Claim 12
Dependent Claim
22 words
The membrane as described in claim 2 wherein the polymer is a polyamide reverse osmosis discriminating layer affixed to a porous support.
Claim 13
Dependent Claim
15 words
The membrane as described in claim 11 wherein the porous support is made from polysulfone.
Claim 14
Dependent Claim
17 words
The membrane as described in claim 12 wherein the membrane is a flat sheet or spiral membrane.
Claim 15
Dependent Claim
45 words
The membrane as described in claim 11 wherein the water flux of the membrane at a pressure of 200 psi and a temperature of 25° C. using a 0.2 weight percent aqueous NaCl solution is at least 10 percent difunctional or polyfunctional carboxylic acid compound.
Claim 16
Dependent Claim
33 words
The membrane as described in claim 1 wherein a plurality of the primary amine groups in the polyamide are reacted with nitrous acid or an equivalent to form diazonium salts or derivatives thereof.
Claim 17
Dependent Claim
24 words
The membrane as described in claim 1 wherein the polymer is a water-soluble polymer bearing a plurality of primary amine and carboxylic acid groups.
Claim 18
Dependent Claim
30 words
The membrane as described in claim 16 wherein the polymer is a copolymer of acrylic acid or methacrylic acid and an ethylenically unsaturated monomer bearing an aliphatic primary amine group.
Claim 19
Dependent Claim
30 words
The membrane as described in claim 1 wherein the polymer is a water-soluble polymer bearing a plurality of primary amine groups neutralized with a difunctional or polyfunctional carboxylic acid compound.
Claim 20
Dependent Claim
30 words
The membrane as described in claim 1 wherein the polymer is a water-soluble polymer bearing a plurality of carboxylic acid groups neutralized with a difunctional or polyfunctional primary amine groups.
Claim 21
Dependent Claim
33 words
In a process for separating water from a mixture or solution using a reverse osmosis membrane having a polyamide discriminating layer, wherein the improvement comprises using a membrane as described in claim 2.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-03-13 | 1992-09-12 | 1993-03-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-03-13 | 1996-09-12 | 1997-03-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-03-13 | 2000-09-12 | 2001-03-14 | $7700.00 | Window Closed / Lapsed |