Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A process for preparing alpha phase quinacridone pigment by ring-closing 2,5-dianilino-terephthalic acid in concentrated polyphosphoric acid, treatment with at least one glycol, followed by striking to water and conditioning the resulting washed pigment with alcohol in the presence of alkali. The resulting pigment is considerably opaque and yellow versus gamma quinacridone of large particle size.

Abstract: This invention relates to a method for production of nanoscale size quinacridones through a wet-salt attrition process by combining a crude quinacridone pigment in the presence of (i) an inorganic salt, (ii) an organic liquid in which the quinacridone pigment and salt are substantially insoluble, and (iii) a quinacridone derivative in an amount less than 10 wt. % relative to the quinacridone pigment; discharging the ground quinacridone pigment into water; adding an acid to produce a solution pH of 1.5 or lower; and isolating the quinacridone pigment.

Abstract: A process for the manufacture of a transparent Pigment Yellow 155 or transparent Pigment Yellow 180 is disclosed, said process includes grinding particles of said pigment in the presence of a grinding agent until said particles achieve a surface area of at least about 40 m2/g.

Abstract: A process for conditioning azo pigment with surfactants of ethoxylate alkyl phenols in the presence of a strong alkali in the aqueous condition.

Abstract: A process for by oxidizing a quinacridone in a liquid medium with a non-metal oxidant producing a quinacridonequinone.

Abstract: A method of conditioning an organic crude pigment by treating, under high shear, 1 part by weight of the crude pigment and about 0.5 to 1.9 parts by weight of polyphosphoric acid or polyphosphoric acid methyl ester at a temperature ranging from about 90 to 160° C.

Abstract: A method of acid swelling crude perylene pigment by treating the crude with about 2 to 10 parts by weight of toluene sulfonic acid at an elevated pressure and at temperatures ranging from 40 to 140° C.

Abstract: An improved process for producing a substantially pure gamma phase a quinacridone pigment or pigment derivative involving preparing an aqueous slurry of a crude quinacridone in the presence of caustic alkali and a non-polar, water immiscible solvent; and heating said slurry at a temperature above about 120° C.

Abstract: An improved process for producing a substantially pure gamma phase a quinacridone pigment or pigment derivative involving preparing an aqueous slurry of a crude quinacridone in the presence of caustic alkali and a non-polar, water immiscible solvent; and heating said slurry at a temperature above about 120° C.