Patent US2721170A successfully refreshed from Google Patents.
US2721170A
Expired / Lapsed
US
⏱️ 0.0 years remaining
johnson
Assignee: —
•
Filing: —
•
Granted: 1955-10-18
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Expires: 1972-10-18
Abstract
No abstract record available.
Inventors
No inventors recorded.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 20:16
CPC Classifications
C; C07; C07C; C07C29/00; C07C29/74; C07C29/76; C07C29/80; C07C29/84; C07C15/00; C07C15/02; C07C15/067; C07C15/08; C07C7/00; C07C7/04; C07C7/05; C07C7/08
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
84 words
THE METHOD OF SEPARATING ORTHO XYLENE BY EXTRACTIVE DISTILLATION FROM PETROLEUM DISTILLATE FRACTIONS CONTAINING ISOMERIC XYLENES WHICH COMPRISES PASSING THE FRACTION AT A TEMPERATURE IN THE RANGE APPROXIMATING 310* TO 330* F. TO A FRACTIONAL DISTILLATION ZONE, TAKING OFF OVERHEAD A LIGHTER FRACTION WHOSE BOILING RANGE INCLUDES THE LARGER PORTION OF THE XYLENE ISOMERS WHILE REMOVING AS BOTTOMS THE CONSTITUENTS BOILING HIGHER THAN ORTHO XYLENE, PASSING THE XYLENE CONCENTRATE IN VAPOR PHASE AT A TEMPERATURE OF ABOUT 300* TO 320* F. TO AN EXTRACTIVE
Claim 2
Independent Claim
84 words
THE METHOD OF SEPARATING ORTHO XYLENE BY EXTRACTIVE DISTILLATION FROM PETROLEUM DISTILLATE FRACTIONS CONTAINING ISOMERIC XYLENES WHICH COMPRISES PASSING THE FRACTION AT A TEMPERATURE IN THE RANGE APPROXIMATING 310* TO 330* F. TO A FRACTIONAL DISTILLATION ZONE, TAKING OFF OVERHEAD A LIGHTER FRACTION WHOSE BOILING RANGE INCLUDES THE LARGER PORTION OF THE XYLENE ISOMERS WHILE REMOVING AS BOTTOMS THE CONSTITUENTS BOILING HIGHER THAN ORTHO XYLENE, PASSING THE XYLENE CONCENTRATE IN VAPOR PHASE AT A TEMPERATURE OF ABOUT 300* TO 320* F. TO AN EXTRACTIVE
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) | 1958-10-17 | 1959-04-18 | 1959-10-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1962-10-17 | 1963-04-18 | 1963-10-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1966-10-17 | 1967-04-18 | 1967-10-18 | $7700.00 | Window Closed / Lapsed |