Patent US2689654A successfully refreshed from Google Patents.
Patent US3031501A successfully refreshed from Google Patents.
US3031501A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Preparation of 2, 5-diarylamino-tereph-thalic acid and salts thereof
Assignee: EIDP Inc
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Filing: 1958-06-16
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Granted: 1962-04-24
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Expires: 1978-06-16
Abstract
No abstract record available.
Inventors
- 👤 William S Struve
- 👤 Albert D Reidinger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 03:47
CPC Classifications
C; C07; C07D; C07D213/00; C07D213/02; C07D213/04; C07D213/60; C07D213/62; C07D213/63; C07D213/68; C07C; C07C303/00; C07C303/32; C07C63/00; C07C63/14; C07C63/15; C07C63/26
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
55 words
A PROCESS FOR THE PREPARATION OF A 2,5-DIARYLAMINOTEREPHTHALIC ACID COMPRISING SIMULTANEOUSLY SAPONIFYING AND OXIDIZING A LOWER DIALKYL 2,5-DIARYLAMINO-3,6-DIHYDROTEREPHTHALATE BY HEATING SAID TEREPHTHALATE IN AN AQUEOUS SOLUTION OF AN ALKALI METAL HYDROXIDE CONTAINING A MILD OXIDIZING AGENT SELECTED FROM THE GROUP CONSISTING OF AIR AND NITROBENZENE-META-SODIUM SULFONATE, AND ACIDIFYING THE REACTION MIXTURE TO PRODUCE 2,5-DIARYLAMINO-TEREPHTHALIC ACID.
Claim 2
Dependent Claim
55 words
A PROCESS FOR THE PREPARATION OF A 2,5-DIARYLAMINOTEREPHTHALIC ACID COMPRISING SIMULTANEOUSLY SAPONIFYING AND OXIDIZING A LOWER DIALKYL 2,5-DIARYLAMINO-3,6-DIHYDROTEREPHTHALATE BY HEATING SAID TEREPHTHALATE IN AN AQUEOUS SOLUTION OF AN ALKALI METAL HYDROXIDE CONTAINING A MILD OXIDIZING AGENT SELECTED FROM THE GROUP CONSISTING OF AIR AND NITROBENZENE-META-SODIUM SULFONATE, AND ACIDIFYING THE REACTION MIXTURE TO PRODUCE 2,5-DIARYLAMINO-TEREPHTHALIC ACID.
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) | 1965-04-23 | 1965-10-23 | 1966-04-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1969-04-23 | 1969-10-23 | 1970-04-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1973-04-23 | 1973-10-23 | 1974-04-24 | $7700.00 | Window Closed / Lapsed |