US4460796A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Purification of polytetramethylene ether-glycols
Assignee: BASF SE
•
Filing: 1982-02-10
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Granted: 1984-07-17
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Expires: 2002-02-10
Abstract
Abstract Polytetramethylene etherglycols are purified by treating the alkaline catalysts with orthophosphoric acid in an equivalence ratio of from 1.5 to 2.5:3 and then separating off the inorganic salts formed.
Inventors
- 👤 Herbert Mueller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 13:08
CPC Classifications
C; C08; C08G; C08G65/00; C08G65/02; C08G65/30; C08G65/04; C08G65/06; C08G65/16; C08G65/20
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
76 words
A process for the purification of polytetramethylene ether-glycols containing basic trans-esterification catalyst which comprises: adding to the polytetramethylene ether-glycol to be purified orthophosphoric acid to provide an equivalence ratio of basic catalyst to orthophosphoric acid of from 1.5 to 2.5:3 and thereby neutralize said basic catalyst, and thereafter separating the salts that are formed from the polytetramethylene ether-glycol, producing a polytetramethylene ether-glycol, free from any inorganic impurities and having an acid or base number of zero.
Claim 2
Dependent Claim
76 words
A process for the purification of polytetramethylene ether-glycols containing basic trans-esterification catalyst which comprises: adding to the polytetramethylene ether-glycol to be purified orthophosphoric acid to provide an equivalence ratio of basic catalyst to orthophosphoric acid of from 1.5 to 2.5:3 and thereby neutralize said basic catalyst, and thereafter separating the salts that are formed from the polytetramethylene ether-glycol, producing a polytetramethylene ether-glycol, free from any inorganic impurities and having an acid or base number of zero.
References Cited (Backward Citations)
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US2983763A
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GB877269A
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US3030426A
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US3016404A
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US3712930A
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US3833669A
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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) | 1987-07-17 | 1988-01-16 | 1988-07-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-07-17 | 1992-01-16 | 1992-07-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-07-17 | 1996-01-16 | 1996-07-17 | $7700.00 | Window Closed / Lapsed |