Abstract: This invention relates to a continuous process for preparing perylenes by (a) continuously mixing a melt of the leuco form of a perylene tetracarboxylic diimide obtained by alkaline fusion of naphthalimide with a continuous water-containing stream containing (1) 2 to 50 parts of water per part of melt, (2) 0 to X1 moles of oxidizing agent per mole of the leuco form, (3) 0 to Y1 parts by weight of processing additives, based on the leuco form, and (4) 0 to Z1 parts by weight of an acid, based on the leuco form of the perylene tetracarboxylic diimide, to form a slurry; and (b) optionally mixing the slurry in one or more continuous or batchwise steps with a second stream containing (1) 0 to 10 parts by weight of water, based on the slurry, (2) 0 to X2 moles of oxidizing agent per mole of the leuco form of the perylene tetracarboxylic diimide, with the proviso the total of X1 and X2 represents at least the molar amount of oxidizing agent theoretically needed to oxidize all of the leuco form of the perylene tetr

Abstract: This invention relates to a continuous process for the preparation of quinacridone pigments by(a) preparing a reaction mixture by mixing(i) a 2,5-dianilinoterephthalic acid or ester thereof, and(ii) at least about 0.5 parts by weight, per part of component (a)(i), of a dehydrating agent;(b) passing the reaction mixture through a continuous reactor having one or more heated zones at a temperature of about 80.degree. C. to about 300.degree. C. to form a crude quinacridone composition; and(c) mixing a continuous stream of the crude quinacridone composition with a liquid in which the quinacridone pigment is substantially insoluble at a ratio of about 0.5 to about 15 parts by weight of the liquid per part by weight of the crude quinacridone composition.

Abstract: This invention relates to a process for removing copper ions from highly acidic waste water generated during the manufacture of dyes or pigments or intermediates thereof. The waste water is exposed at a pH less than about 1 to a bed of suspended iron particles, preferably a fluidized bed of iron particles, having a particle size of from about 200 to about 950 micrometers.