Sun Chemical Corporation

Tracie Tibbs

Daphne J Rice

Brian L Thompson

Wengan Wu

Thomas R Flatt

Richard Kent Faubion

Bobby Mims

Edward H Sung

John Britanak

Daphne Rice

2,5-di(p-methoxyanilino)terephthalic acid crystal types I and II are made by controlling the pH during the recovery of the oxidized product of the condensation of dimethylsuccinyl succinate with p-methoxyaniline. The resulting 2,5-di(p-methoxyanilino)-terephthalic acid can be converted into 2,9-dimethoxyquinacridone or a solid solution thereof having controlled characteristics.

2,5-di(methoxyanilino) terephthalic acid polymorphs and quinacridones realized therefrom

Novel crystal forms of solid solutions of 2,9-dimethyoxyquinacridone and 2,9-dichloroquinacridone. The crystal forms may be formed by a process comprising the steps of: a) heating a mixture of 2,5-di(4-methoxyanilino)terephthalic acid, and 2,5-di(4-chloroanilino)terephthalic acid in polyphorsphoric acid at a temperature less than 1050 C to form a mixture of 2,9-dimethoxyquinacridone and 2,9-dichloroquinacridone; b) combining the mixture of 2,9-dimethoxyquinacridone and 2,9-dichloroquinacridone with water; and c) heating the mixture of 2,9-dimethoxyquinacridone and 2,9-dichloroquinacridone at a temperature not more than 110&#xb0; C. Another crystal form may be formed by the process of heating a mixture of 2,9-dimethoxyquinacridone and 2,9-dichloroquinacridone in a polar aprotic solvent. These products are may be used for coloring fibers, plastics, paints, coatings, printing inks, color filters, cosmetics, automotive coatings, textiles, fibers, powder coatings, in-mold coatings, laminate films, and the like.

Crystal forms of quinacridones made from 2,9-dimethoxyquinacridone and 2,9-dichloroquinacridone

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Tracie Tibbs