US3880914A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Diperisophthalic acids
Assignee: PPG Industries Inc
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Filing: 1971-08-03
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Granted: 1975-04-29
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Expires: 1991-08-03
Abstract
Abstract Diperphthalic acids are prepared from hydrogen peroxide and the phthalic acid in an alkanesulfonic acid reaction medium by using finely subdivided phthalic acid with a particle dimension below 0.1 millimeter, more notably in the range of from 0.001 to 0.1 millimeter. A unique crystal form of diperisophthalic acid is obtained, for example, by reaction of isophthalic acid of less than 0.044 millimeter (less than 325 mesh).
Inventors
- 👤 Donald R Nielsen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 14:58
CPC Classifications
C; C07; C07C; C07C407/00; C07B; C07B2200/00; C07B2200/13
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
62 words
A SOLID DIPERISOPTHALIC ACID COMPOSITION, THE DIPERISOPHTHALIC ACID CONTENT OF WHICH CONSISTS ESSENTIALLY OF DIPERISOPHTHALIC ACID IN THAT CRYSTAL FORM HAVING CHARACTERISTIC X-RAY DIFFRACTION POWDER PATTERN INTERPLANAR SPACINGS AS FOLLOWS: A 9.17 5.50 5.21 3.75 3.54 3.26 3.20 3.15 2.44 2.39 2.30 1.97 1.93 1.87 1.84 1.80 1.61 AND HAVING MAJOR LINE INTENSITIES AT INTERPLANAR SPACINGS OF 4.21, 3.20 AND 2.39 A.
Claim 2
Dependent Claim
62 words
A SOLID DIPERISOPTHALIC ACID COMPOSITION, THE DIPERISOPHTHALIC ACID CONTENT OF WHICH CONSISTS ESSENTIALLY OF DIPERISOPHTHALIC ACID IN THAT CRYSTAL FORM HAVING CHARACTERISTIC X-RAY DIFFRACTION POWDER PATTERN INTERPLANAR SPACINGS AS FOLLOWS: A 9.17 5.50 5.21 3.75 3.54 3.26 3.20 3.15 2.44 2.39 2.30 1.97 1.93 1.87 1.84 1.80 1.61 AND HAVING MAJOR LINE INTENSITIES AT INTERPLANAR SPACINGS OF 4.21, 3.20 AND 2.39 A.
Claim 3
Dependent Claim
70 words
An aqueous slurry of a metastable normal tabular habit diperisophthalic acid product having characteristic X-ray diffraction powder pattern interplanar spacings as follows: A 9.17 5.50 4.21 3.75 3.54 3.26 3.20 3.15 2.44 2.39 2.30 1.97 1.93 1.87 1.84 1.80 1.61 and having major line intensities at interplanar spacing of 4.21, 3.20 and 2.39 A, said product being characterized by maintaining said characteristic X-ray diffraction powder pattern in said aqueous media.
Claim 4
Dependent Claim
70 words
An aqueous slurry of a metastable normal tabular habit diperisophthalic acid product having characteristic X-ray diffraction powder pattern interplanar spacings as follows: A 9.17 5.50 4.21 3.75 3.54 3.26 3.20 3.15 2.44 2.39 2.30 1.97 1.93 1.87 1.84 1.80 1.61 and having major line intensities at interplanar spacing of 4.21, 3.20 and 2.39 A, said product being characterized by maintaining said characteristic X-ray diffraction powder pattern in said aqueous media.
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) | 1978-04-28 | 1978-10-28 | 1979-04-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-28 | 1982-10-28 | 1983-04-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-28 | 1986-10-28 | 1987-04-29 | $7700.00 | Window Closed / Lapsed |