Process for the preparation of beta-phase quinacridone
US6494949B2 · kind B2 · utility
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10Claims
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Key dates
| Filing date | Jan 5, 2001 |
| Grant date | Dec 17, 2002 |
| Priority date | — |
| Expiry date | Jan 5, 2021 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09B67/0036
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
A process for producing beta-phase quinacridone by (a) reacting 2,5-dianilino-terephthalic acid with polyphosphoric acid in the presence of 2,5-dianisidino-terephthalic acid at a reaction temperature of at least 85° C.; (b) diluting the reaction mixture with water; (c) drowning the diluted mixture in a water-miscible alkanol; (d) heating the slurry at a temperature of from 100 to 130° C. at a pressure of 20 to 50 psi; and (e) recovering the beta-phase quinacridone.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.