US2993841A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Extractive distillation with dimethylformamide
Assignee: Shell USA Inc
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Filing: 1959-09-25
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Granted: 1961-07-25
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Expires: 1979-09-25
Abstract
No abstract record available.
Inventors
- 👤 Dante H Sarno
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 05:08
CPC Classifications
C; C07; C07C; C07C7/00; C07C7/04; C07C7/05; C07C7/08
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
170 words
IN AN EXTRACTIVE DISTILLATION PROCESS FOR THE RECOVERY OF AN UNSATURATED C4 TO C6 INCLUSIVE HYDROCARBON FROM A MIXTURE THEREOF CONTAINING A CLOSE BOILING, MORE SATURATED MATERIAL OF LIKE CARBON NUMBER EMPLOYING DIMETHYLFORMAMIDE AS THE SOLVENT AND WHEREIN THERE IS FORMED A SOLVENT EXTRACT PHASE ENRICHED IN THE UNSATURATED MATERIAL, THE STEPS COMPRISING INTRODUCING AN INERT HYDROCARBON DILUENT TO THE BOTTOM PORTION OF THE EXTRACTIVE DISTILLATION ZONE, SAID DILUENT HAVING AT LEAST ONE MORE CARBON ATOM THAN THE UNSATURATED MATERIAL AND CHARACTERIZED BY HAVING A LOWER BOILING POINT LESS THAN THAT OF THE DIMETHYLFORMAMIDE, REMOVING THE EXTRACT PHASE INCLUDING THE DILUENT TO A STRIPPING ZONE AND THERE SEPARATING OVERHEAD A VAPOR STREAM OF THE UNSATURATED MATERIAL, LEAVING AS LIQUID BOTTOMS THE DILUENT AND DIMETHYLFORMAMIDE SOLVENT, TRANSFERRING THE LIQUID BOTTOMS TO A SOLVENT RECOVERY DISTRILLATION ZONE AND THERE REMOVING THE DILUENT OVERHEAD, LEAVING A LEAN DIMETHYLFORMAMIDE SOLVENT; RECYCLING THE DIMETHYLFORMAMIDE SOLVENT TO AN UPPER PORTION OF THE EXTRACTIVE DISTILLATION ZONE AND RETURNING THE DILUENT TO THE BOTTOM PORTION OF SAID ZONE.
Claim 2
Dependent Claim
170 words
IN AN EXTRACTIVE DISTILLATION PROCESS FOR THE RECOVERY OF AN UNSATURATED C4 TO C6 INCLUSIVE HYDROCARBON FROM A MIXTURE THEREOF CONTAINING A CLOSE BOILING, MORE SATURATED MATERIAL OF LIKE CARBON NUMBER EMPLOYING DIMETHYLFORMAMIDE AS THE SOLVENT AND WHEREIN THERE IS FORMED A SOLVENT EXTRACT PHASE ENRICHED IN THE UNSATURATED MATERIAL, THE STEPS COMPRISING INTRODUCING AN INERT HYDROCARBON DILUENT TO THE BOTTOM PORTION OF THE EXTRACTIVE DISTILLATION ZONE, SAID DILUENT HAVING AT LEAST ONE MORE CARBON ATOM THAN THE UNSATURATED MATERIAL AND CHARACTERIZED BY HAVING A LOWER BOILING POINT LESS THAN THAT OF THE DIMETHYLFORMAMIDE, REMOVING THE EXTRACT PHASE INCLUDING THE DILUENT TO A STRIPPING ZONE AND THERE SEPARATING OVERHEAD A VAPOR STREAM OF THE UNSATURATED MATERIAL, LEAVING AS LIQUID BOTTOMS THE DILUENT AND DIMETHYLFORMAMIDE SOLVENT, TRANSFERRING THE LIQUID BOTTOMS TO A SOLVENT RECOVERY DISTRILLATION ZONE AND THERE REMOVING THE DILUENT OVERHEAD, LEAVING A LEAN DIMETHYLFORMAMIDE SOLVENT; RECYCLING THE DIMETHYLFORMAMIDE SOLVENT TO AN UPPER PORTION OF THE EXTRACTIVE DISTILLATION ZONE AND RETURNING THE DILUENT TO THE BOTTOM PORTION OF SAID ZONE.
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) | 1964-07-24 | 1965-01-23 | 1965-07-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1968-07-24 | 1969-01-23 | 1969-07-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1972-07-24 | 1973-01-23 | 1973-07-25 | $7700.00 | Window Closed / Lapsed |