Back to results
US 4,145,356 AGranted
Process of preparing pyranthrone pigments
AssigneeBASF SE
InventorFritz Graser
Life of this patent
Estimating the term…
Abstract
Pyranthrone pigments of the formula ##STR1## WHEREIN N IS 0 OR 1, WHEREIN WHEN N IS 0, EACH A is hydrogen or chlorine, and when n is 1, each A is chlorine are prepared by crystallizing a finely divided crude pyranthrone pigment in an organic polar solvent, in the presence of from 0.5 to 10% by weight, based on the crude pigment, of an anthraquinone compound of the formula ##STR2## WHEREIN X is chlorine, Y is alkyl of 1 to 4 carbon atoms, hydroxyl, carboxyl, carbo-alkoxy, wherein said alkoxy group has 1 to 4 carbon atoms, or carbophenoxy, p is 0, 1 or 2 and m is 0, 1 or 2.
Claims12
A process for the production of pyrnathrone pigments of the formula:
- ##STR5## wherein n may be 0 or 1, wherein when n is 0, each A is hydrogen or chlorine, and when n is 1, each A is chlorine, which comprises:
- crystallizing a finely divided crude pigment of the above formula, obtained by milling or dissolving a crude pigment of the above formula in sulfuric acid and then precipitating said dissolved pigment, in at least one polar organic solvent in the presence of from 0.5 to 10% by weight, based on the pyranthrone compound, of at least one anthraquinone compound of the formula:
- ##STR6## wherein X is chlorine, Y is alkyl of 1 to 4 carbon atoms, hydroxyl, carboxyl, carbo-alkoxy, wherein alkoxy is of 1 to 4 carbon atoms, or carbophenoxy, p is 0, 1 or 2 and m is 0, 1 or 2.
Dependencies are inferred from the claim text.