US4100162A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparing gamma quinacridone from polyphosphoric acid and alcohol
Assignee: Bayer Corp
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Filing: 1977-01-17
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Granted: 1978-07-11
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Expires: 1997-01-17
Abstract
Abstract A method is provided for the direct production of gamma quinacridone pigment comprising ring closure of 2,5-dianilinoterephthalic acid in polyphosphoric acid and diluting the mixture by addition thereof into a water-miscible alcohol containing 1-3 carbon atoms, e.g. methanol, while maintaining the temperature of the alcohol-acid at between 0° and 25° C.
Inventors
- 👤 Robert Jarl North
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 10:39
CPC Classifications
C; C09; C09B; C09B48/00
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
77 words
A process for the direct production of gamma quinacridone pigment which comprises heating, at a temperature between 80° and 120° C. 2,5-dianilinoterephthalic acid in polyphosphoric aicd, diluting the reaction mixture by addition thereof to a water-miscible alcohol containing 1 to 3 carbon atoms in an amount sufficient to dissolve the polyphosphoric acid while maintaining the temperature of the alcohol between about 0° and 25° C. during said addition, and thereafter separating gamma quinacridone from the resulting mixture.
Claim 2
Dependent Claim
77 words
A process for the direct production of gamma quinacridone pigment which comprises heating, at a temperature between 80° and 120° C. 2,5-dianilinoterephthalic acid in polyphosphoric aicd, diluting the reaction mixture by addition thereof to a water-miscible alcohol containing 1 to 3 carbon atoms in an amount sufficient to dissolve the polyphosphoric acid while maintaining the temperature of the alcohol between about 0° and 25° C. during said addition, and thereafter separating gamma quinacridone from the resulting mixture.
Claim 3
Dependent Claim
20 words
A process as defined in claim 1 wherein the polyphosphoric acid has an acid content of at least 100 percent.
Claim 4
Dependent Claim
12 words
A process as defined in claim 1 wherein the alcohol is methanol.
Claim 5
Dependent Claim
22 words
A process as defined in claim 1 wherein the temperature of the alcohol is maintained at between about 15° and 0° C.
Claim 6
Dependent Claim
21 words
A process as defined in claim 4 wherein the temperature of the methanol is maintained between about 15° and 0° C.
References Cited (Backward Citations)
US3257405A
Cited
US3265699A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-07-10 | 1982-01-09 | 1982-07-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-07-10 | 1986-01-09 | 1986-07-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-07-10 | 1990-01-09 | 1990-07-11 | $7700.00 | Window Closed / Lapsed |