US4212975A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the manufacture of the gamma-crystal modification of linear trans-quinacridone
Assignee: Hoechst AG
•
Filing: 1978-10-19
•
Granted: 1980-07-15
•
Expires: 1998-10-19
Abstract
Abstract Unsubstituted linear trans-quinacridone of the gamma-crystal modification is obtained by cyclization of 2,5-dianilino-terephthalic acid with the 2.5 to 4-fold quantity of polyphosphoric acid or of an acidic polyphosphoric acid methyl ester, followed by hydrolysis of the condensation product in water, intensive grinding of the aqueous crude quinacridone in the presence of an alcohol or ketone and heating of the resulting product to 80° to 200° C.
Inventors
- 👤 Adolf Kroh
- 👤 Otto Fuchs
- 👤 Ernst Spietschka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 08:59
CPC Classifications
C; C09; C09B; C09B48/00
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
97 words
A process for making the gamma-crystal modification of the unsubstituted linear trans-quinacridone which comprises cyclizing 2,5-dianilino-terephthalic acid with a 2,5-fold to 4-fold quantity by weight of a condensing agent that is polyphosphoric acid or an acidic polyphosphoric acid methyl ester, hydrolyzing the reaction mixture in water to form crude quinacridone agglomerates, separating the crude quinacridone agglomerates and mixing them with a solvent selected from alcohols and ketones having up to 6 carbon atoms, intensively milling the quinacridone agglomerates in admixture with the solvent and heating the resulting mixture to a temperature of 80° C. to 200° C.
Claim 2
Dependent Claim
97 words
A process for making the gamma-crystal modification of the unsubstituted linear trans-quinacridone which comprises cyclizing 2,5-dianilino-terephthalic acid with a 2,5-fold to 4-fold quantity by weight of a condensing agent that is polyphosphoric acid or an acidic polyphosphoric acid methyl ester, hydrolyzing the reaction mixture in water to form crude quinacridone agglomerates, separating the crude quinacridone agglomerates and mixing them with a solvent selected from alcohols and ketones having up to 6 carbon atoms, intensively milling the quinacridone agglomerates in admixture with the solvent and heating the resulting mixture to a temperature of 80° C. to 200° C.
Claim 3
Dependent Claim
19 words
The process as claimed in claim 1, which comprises heating the suspension after grinding to 100° to 170° C.
Claim 4
Dependent Claim
19 words
The process as claimed in claim 1, which comprises heating the suspension after grinding to 125° to 160° C.
Claim 5
Dependent Claim
19 words
The process as claimed in claim 1, which comprises carrying out cyclization with a three-fold quantity of condensation agent.
Claim 6
Dependent Claim
21 words
The process as claimed in claim 1, which comprises carrying out cyclization at a temperature of from 100° to 150° C.
Claim 7
Dependent Claim
17 words
The process as claimed in claim 1, which comprises carrying out cyclization at 120° to 130° C.
Claim 8
Dependent Claim
27 words
The process as claimed in claim 1, which comprises carrying out grinding with the addition of a two- to five-fold quantity of solvent, calculated on the quinacridone.
Claim 9
Dependent Claim
21 words
The process as claimed in claim 1, which comprises heating the suspension obtained on grinding in a closed vessel while stirring.
Claim 10
Dependent Claim
20 words
The process as claimed in claim 1, which comprises heating the suspension obtained on grinding for 4 to 6 hours.
Claim 11
Dependent Claim
16 words
The process as claimed in claim 1, which comprises isolating the crude quinacridone obtained on hydrolyzing.
Claim 12
Dependent Claim
17 words
The process as claimed in claim 1, which comprises washing neutral the crude quinacridone obtained on hydrolyzing.
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) | 1983-07-15 | 1984-01-14 | 1984-07-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-07-15 | 1988-01-14 | 1988-07-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-07-15 | 1992-01-14 | 1992-07-15 | $7700.00 | Window Closed / Lapsed |