Patent US2786805A successfully refreshed from Google Patents.
US2786805A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process of purification of phthalic anhydride
Assignee: California Research LLC
•
Filing: 1954-03-01
•
Granted: 1957-03-26
•
Expires: 1974-03-01
Abstract
No abstract record available.
Inventors
- 👤 Eugene F Sullivan
- 👤 Albert S Guerard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 07:00
CPC Classifications
C; C07; C07C; C07C51/00; C07C51/54; C07C51/573
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
95 words
THE METHOD OF PURIFYING PHTHALIC ANHYDRICE WHICH COMPRISES MIXING SUFFICIENT WATER WITH THE PHTHALIC ANHYDRIDE TO FORM A PUMPABLE SLURRY COMPRISING THE PHTAHLIC ACID AND WATER, HEATING THE SLURRY IN A DISTILLATION ZONE TO A TEMPERATURE SUFFICIENT TO CAUSE EVAPORATION OF WATER AND PHTHALIC ANHYDRIDE, PASSING STEAM INTO THE DISTILLATION ZONE, REMOVING STEAM AND PHTHALIC ANHYDRIDE VAPOR OVERHEAD FROM SAID DISTILLATION ZONE, COOLING THE OVERHEAD VAPORS TO ABOUT 300* F. TO PRODUCE A LIQUID CONDENSATE CONSISTING PREDOMINANTLY OF PHTHALIC ANHYDRIDE AND FREE OF WATER AND FRACTIONALLY DISTILLING THE CONDENSATE TO RECOVER PURIFIED PHTHALIC ANHYDRIDE OVERHEAD.
Claim 2
Independent Claim
95 words
THE METHOD OF PURIFYING PHTHALIC ANHYDRICE WHICH COMPRISES MIXING SUFFICIENT WATER WITH THE PHTHALIC ANHYDRIDE TO FORM A PUMPABLE SLURRY COMPRISING THE PHTAHLIC ACID AND WATER, HEATING THE SLURRY IN A DISTILLATION ZONE TO A TEMPERATURE SUFFICIENT TO CAUSE EVAPORATION OF WATER AND PHTHALIC ANHYDRIDE, PASSING STEAM INTO THE DISTILLATION ZONE, REMOVING STEAM AND PHTHALIC ANHYDRIDE VAPOR OVERHEAD FROM SAID DISTILLATION ZONE, COOLING THE OVERHEAD VAPORS TO ABOUT 300* F. TO PRODUCE A LIQUID CONDENSATE CONSISTING PREDOMINANTLY OF PHTHALIC ANHYDRIDE AND FREE OF WATER AND FRACTIONALLY DISTILLING THE CONDENSATE TO RECOVER PURIFIED PHTHALIC ANHYDRIDE OVERHEAD.
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) | 1960-03-25 | 1960-09-24 | 1961-03-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1964-03-25 | 1964-09-24 | 1965-03-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1968-03-25 | 1968-09-24 | 1969-03-26 | $7700.00 | Window Closed / Lapsed |