US4806245A
Expired / Lapsed
US
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Pervaporation of phenols
Assignee: Bend Research Inc
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Filing: 1988-03-21
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Granted: 1989-02-21
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Expires: 2008-03-21
Abstract
Abstract Aqueous phenolic solutions are separated by pervaporation to yield a phenol-depleted retentate and a phenol-enriched permeate. The separation effect is enhanced by phase segregation into two immiscible phases, "phenol in water" (approximately 10% phenol), and "water in phenol" (approximately 70% phenol). Membranes capable of enriching phenols by pervaporation include elastomeric polymers and anion exchange membranes, membrane selection and process design being guided by pervaporation performance and chemical stability towards phenolic solutions. Single- and multiple-stage procresses are disclosed, both for the enrichment of phenols and for purification of water from phenolic contamination.
Inventors
- 👤 Karl W. Boddeker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 20:03
CPC Classifications
B; B01; B01D; B01D61/00; B01D61/36; B01D61/362; B01D61/3621; B01D71/00; B01D71/06; B01D71/56; B01D2317/00; B01D2317/02; B01D2317/025
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
197 words
A pervaporation method of selectively enriching the phenolic content of the permeate of an aqueous phenolic feed solution without pH adjustment, said phenolic content enrichment of said permeate increasing with decreasing phenolic concentration of said feed solution so as to permit increasing said phenolic content of said permeate to a phenolic concentration at which natural phase separation spontaneously occurs, said method comprising at least one pervaporation step of forming a vaporized phenol-enriched permeate comprising both phenols and water in a vapor state by (a) contacting the feed side of a nonporous polymeric membrane having a feed side and a permeate side with an aqueous phenol-containing feed stream, said membrane not being degraded by phenols and selected from the group consisting essentially of elastomeric polymers and anion exchange polymers, while (b) maintaining on the permeate side of said membrane either a pressure of 10 mmHg or less or an inert gas sweep stream, whereby phenols in said feed stream preferentially permeate said membrane to form a vaporized phenol-enriched permeate comprising both phenols and water in a vapor state on the permeate side of said membrane, and leaving a phenol-depleted water retentate on the feed side of said membrane.
Claim 2
Dependent Claim
197 words
A pervaporation method of selectively enriching the phenolic content of the permeate of an aqueous phenolic feed solution without pH adjustment, said phenolic content enrichment of said permeate increasing with decreasing phenolic concentration of said feed solution so as to permit increasing said phenolic content of said permeate to a phenolic concentration at which natural phase separation spontaneously occurs, said method comprising at least one pervaporation step of forming a vaporized phenol-enriched permeate comprising both phenols and water in a vapor state by (a) contacting the feed side of a nonporous polymeric membrane having a feed side and a permeate side with an aqueous phenol-containing feed stream, said membrane not being degraded by phenols and selected from the group consisting essentially of elastomeric polymers and anion exchange polymers, while (b) maintaining on the permeate side of said membrane either a pressure of 10 mmHg or less or an inert gas sweep stream, whereby phenols in said feed stream preferentially permeate said membrane to form a vaporized phenol-enriched permeate comprising both phenols and water in a vapor state on the permeate side of said membrane, and leaving a phenol-depleted water retentate on the feed side of said membrane.
Claim 3
Dependent Claim
12 words
The method of claim 1 wherein said vaporized phenol-rich permeate is condensed.
Claim 4
Dependent Claim
19 words
The method of claim 1 further including subjecting said phenol-depleted water retentate to at least one additional pervaporation step.
Claim 5
Dependent Claim
52 words
The method of claim 1 wherein said at least one pervaporation step is conducted until the concentration of phenol in said vaporized phenol-enriched permeate exceeds the phenol concentration of the phenol-poor fraction resulting from a naturally-occurring spontaneous phase separation of an aqueous phenolic solution into a phenol-rich fraction and a phenol-poor fraction.
Claim 6
Dependent Claim
52 words
The method of claim 1 or 4 combined with at least one phase separation step, said phase separation step comprising condensing said vaporized phenol-enriched permeate at a phenol concentration exceeding that at which, upon condensation, spontaneous phase separation of said condensed permeate occurs into a first phenol-poor fraction and a phenol-rich fraction.
Claim 7
Dependent Claim
48 words
The method of claim 5 followed by at least one additional pervaporation step applied to said first phenol-poor fraction of said phase separation step to form a second vaporized phenol-enriched permeate wherein the concentration of phenol exceeds a phenol concentration at which, upon condensation, spontaneous phase separation occurs.
Claim 8
Dependent Claim
45 words
The method of claim 6 combined with at least one phase separation step, said phase separation step comprising condensing said second vaporized phenol-enriched permeate, thereby causing spontaneous phase separation of said condensed second vaporized phenol-enriched permeate into a second phenol-poor fraction and a phenol-rich fraction.
Claim 9
Dependent Claim
11 words
The method of claim 5 including combining phase separated phenol-rich fractions.
Claim 10
Dependent Claim
21 words
The method of claim 7 combined with recycling said phase separated second phenol-poor fraction to said phase separated first phenol-poor fraction.
Claim 11
Dependent Claim
16 words
The method of claim 6 including recycling phenol-depleted water retentate to said aqueous phenol-containing feed stream.
Claim 12
Dependent Claim
11 words
The method of claim 5 including recovery of said phenol-rich fractions.
Claim 13
Dependent Claim
16 words
The method of claim 1, 3, 6, or 10 including recovery of said phenol-depleted water retentate.
Claim 14
Dependent Claim
11 words
The method of claim 7 including combining phase separated phenol-rich fractions.
Claim 15
Dependent Claim
14 words
The method of claim 6, 7 or 8 including recovery of said phenol-rich fractions.
References Cited (Backward Citations)
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1992-02-21 | 1992-08-22 | 1993-02-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-02-21 | 1996-08-22 | 1997-02-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-02-21 | 2000-08-22 | 2001-02-21 | $7700.00 | Window Closed / Lapsed |