Patent US3556991A successfully refreshed from Google Patents.
US3556991A
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US
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Method for the solvent extraction of aromatic hydrocarbons
Assignee: Universal Oil Products Co
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Filing: 1968-12-06
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Granted: 1971-01-19
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Expires: 1988-12-06
Abstract
Abstract PROCESS FOR THE RECOVERY OF AROMATIC HYDROCARBONS USING THE STEPS OF SOLVENT EXTRACTION, DIALYSIS, AND FRACTIONATION OF THE EXTRACT. SULFOLANE IS THE PREFERRED SOLVENT, AND BENZENE IS RECOVERED AS A PREFERRED PRODUCT STREAM.
Inventors
- 👤 Clarence G Gerhold
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 03:49
CPC Classifications
C; C10; C10G; C10G31/00; C10G31/11; B; B01; B01D; B01D61/00; B01D61/24; B01D61/243; B01D71/00; B01D71/06; B01D71/08; B01D71/12; C07; C07C; C07C7/00; C07C7/10
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-01-18 | 1974-07-20 | 1975-01-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-01-18 | 1978-07-20 | 1979-01-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-01-18 | 1982-07-20 | 1983-01-19 | $7700.00 | Window Closed / Lapsed |