US4348262A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Refining tetrahydrofuran
Assignee: EIDP Inc
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Filing: 1981-05-04
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Granted: 1982-09-07
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Expires: 2001-05-04
Abstract
Abstract In the refining of crude acidic tetrahydrofuran prepared from acetylene and formaldehyde, corrosion of refining equipment and formation of color-producing methacrolein can be minimized by bringing the pH value of the crude tetrahydrofuran to within the range 5-11 before the refining step.
Inventors
- 👤 Albert M. Stock
- 👤 Wilson S. Tse
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 21:50
CPC Classifications
B; B01; B01D; B01D3/00; B01D3/34; C; C07; C07D; C07D307/00; C07D307/02; C07D307/04; C07D307/06; C07D307/08
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
54 words
A process for refining crude acidic tetrahydrofuran made from acetylene and formaldehyde, the process comprising adding enough base to the crude tetrahydrofuran to bring its pH value to no more than about 11, but in sufficient amount to hinder the formation of methacrolein while inhibiting corrosion therein, and thereafter distilling the thus treated tetrahydrofuran.
Claim 2
Dependent Claim
54 words
A process for refining crude acidic tetrahydrofuran made from acetylene and formaldehyde, the process comprising adding enough base to the crude tetrahydrofuran to bring its pH value to no more than about 11, but in sufficient amount to hinder the formation of methacrolein while inhibiting corrosion therein, and thereafter distilling the thus treated tetrahydrofuran.
Claim 3
Dependent Claim
21 words
The process of claim 1 in which the pH value of the crude tetrahydrofuran is brought to within the range 7-10.
Claim 4
Dependent Claim
24 words
The process of claim 1 or 2 in which the pH value is brought to the proper level with sodium hydroxide or potassium hydroxide.
Claim 5
Dependent Claim
22 words
The process of claim 1 or 2 in which the pH value is brought to the proper level with a buffer system.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-09-06 | 1986-03-08 | 1986-09-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-09-06 | 1990-03-08 | 1990-09-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-09-06 | 1994-03-08 | 1994-09-07 | $7700.00 | Window Closed / Lapsed |