US3694465A
Expired / Lapsed
US
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Method for concentration of aqueous tetrahydrofuran solutions by extraction with aqueous alkali metal hydroxide
Assignee: Tosoh Corp
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Filing: 1970-08-11
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Granted: 1972-09-26
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Expires: 1990-08-11
Abstract
Abstract A method for producing anhydrous tetrahydrofuran from an aqueous solution of tetrahydrofuran which comprises contacting an aqueous solution of an alkali metal hydroxide with the aqueous solution of tetrahydrofuran to remove the water.
Inventors
- 👤 Hisashi Kisaki
- 👤 Shunsuke Mabuchi
- 👤 Toshikatsu Mizuno
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 06:50
CPC Classifications
C; C07; C07D; C07D307/00; C07D307/02; C07D307/04; C07D307/06; C07D307/08
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
23 words
A method according to claim 1, wherein said alkali metal hydroxide is selected from the group consisting of sodium hydroxide and potassium hydroxide.
Claim 2
Dependent Claim
31 words
A method according to claim 1, wherein the concentration of said alkali metal hydroxide in the resulting residual phase after recovery of the tetrahydrofuran water mixture is more than 20 percent.
Claim 3
Dependent Claim
44 words
A method according to claim 1, wherein said tetrahydrofuran (3) is distilled in a distillation vessel, an azeotropic mixture of water and tetrahydrofuran is removed as an overhead fraction from said vessel, and substantially anhydrous tetrahydrofuran is removed as bottoms fraction from said vessel.
Claim 4
Dependent Claim
23 words
A method according to claim 4, wherein said alkali metal hydroxide is selected from the group consisting of sodium hydroxide and potassium hydroxide.
Claim 5
Dependent Claim
31 words
A method according to claim 4, wherein the concentration of said alkali metal hydroxide in the resulting residual phase after recovery of the tetrahydrofuran water mixture is more than 20 percent.
References Cited (Backward Citations)
US2366464A
Cited
US1466435A
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US2251895A
Cited
US2251835A
Cited
US2795591A
Cited
US2779721A
Cited
US3138545A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-09-26 | 1976-03-27 | 1976-09-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-09-26 | 1980-03-27 | 1980-09-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-09-26 | 1984-03-27 | 1984-09-26 | $7700.00 | Window Closed / Lapsed |