US2702091A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Recovery of molten phthalic anhydride
Assignee: California Research LLC
•
Filing: 1950-05-02
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Granted: 1955-02-15
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Expires: 1970-05-02
Abstract
No abstract record available.
Inventors
- 👤 Jr Calvin S Smith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 13:09
CPC Classifications
B; B01; B01J; B01J8/00; B01J8/08; B01J8/087; C; C07; C07C; C07C51/00; C07C51/54; C07C51/573; B01J2208/00; B01J2208/00008; B01J2208/00017; B01J2208/00026; B01J2208/00035; B01J2208/00088; B01J2208/00106; B01J2208/00168; B01J2208/00256; B01J2208/00327; B01J2208/00336; B01J2208/0038; Y; Y10; Y10S; Y10S159/00; Y10S159/29
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
135 words
THE METHOD OF RECOVERING PHTHALIC ANHYDRIDE FROM A GASEOUS REACTION PRODUCT MIXTURE WHICH COMPRISES INTRODUCING THE REACTION PRODUCT MIXTURE AT A TEMPERATURE ABOVE 400* F. INTO THE LOWER PORTION OF A DOWNWARDLY MOVING BED OF SOLID INORGANIC HEAT EXCHANGE PARTICLES HAVING A SIZE GREATER THAN FIVE MESH, AND HAVING A TEMPERATURE GRADIENT RANGING FROM A TEMPERATURE BELOW THE MELTING POINT OF PHTHALIC ANHYDRIDE IN ITS UPPER PORTION TO A TEMPERATURE ABOVE ABOUT 400* F. IN IT LOWER PORTION, WITHDRAWING COOLED GAS FROM THE UPPER PORTION OF SAID MASS AT A TEMPERATURE SUBSTANTIALLY BELOW THE MELTING POINT OF PHTHALIC ANHYDRIDE AND WITHDRAWING GAS CONTAINING PHTHALIC ANHYDRIDE VAPOR AT A CONCENTRATION SUCH THAT THE PHTHALIC ANHYDRIDE DEW POINT OF THE GAS IS HIGHER THAN THE MELTING POINT OF PHTHALIC ANHYDRIDE FROM AN INTERMEDIATE PORTION OF SAID MASS.
Claim 2
Independent Claim
135 words
THE METHOD OF RECOVERING PHTHALIC ANHYDRIDE FROM A GASEOUS REACTION PRODUCT MIXTURE WHICH COMPRISES INTRODUCING THE REACTION PRODUCT MIXTURE AT A TEMPERATURE ABOVE 400* F. INTO THE LOWER PORTION OF A DOWNWARDLY MOVING BED OF SOLID INORGANIC HEAT EXCHANGE PARTICLES HAVING A SIZE GREATER THAN FIVE MESH, AND HAVING A TEMPERATURE GRADIENT RANGING FROM A TEMPERATURE BELOW THE MELTING POINT OF PHTHALIC ANHYDRIDE IN ITS UPPER PORTION TO A TEMPERATURE ABOVE ABOUT 400* F. IN IT LOWER PORTION, WITHDRAWING COOLED GAS FROM THE UPPER PORTION OF SAID MASS AT A TEMPERATURE SUBSTANTIALLY BELOW THE MELTING POINT OF PHTHALIC ANHYDRIDE AND WITHDRAWING GAS CONTAINING PHTHALIC ANHYDRIDE VAPOR AT A CONCENTRATION SUCH THAT THE PHTHALIC ANHYDRIDE DEW POINT OF THE GAS IS HIGHER THAN THE MELTING POINT OF PHTHALIC ANHYDRIDE FROM AN INTERMEDIATE PORTION OF SAID MASS.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1958-02-14 | 1958-08-16 | 1959-02-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1962-02-14 | 1962-08-16 | 1963-02-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1966-02-14 | 1966-08-16 | 1967-02-15 | $7700.00 | Window Closed / Lapsed |