Abstract: Perylenetetracarbimide mix-crystal pigments in the crystal lattice of the .alpha.-modification of N,N'-bis-3',5'-dimethylphenylperylenetetracarbimide of the formula (1) comprising 99-70 mole percent of the symmetrical diimide of the formula (1) and correspondingly 1-30 mole percent of the asymmetrically substituted diimide of the formula (2) ##STR1## process for their preparation and their use for coloring organic polymers.

Abstract: Process for the preparation of compounds of the formula (1) ##STR1## in which R.sub.1 denotes a phenyl or naphthyl radical which can be substituted by alkyl, cycloalkyl, alkoxy, aryloxy, arylazo or nitro groups or halogen atoms, and R.sub.2 denotes a hydrogen atom or a phenyl or naphthyl radical which can be substituted by alkyl, cycloalkyl, alkoxy, aryloxy, arylazo or nitro groups or halogen atoms, or denotes an alkyl (C.sub.1 -C.sub.8) radical, by condensation, at between 100.degree. C. and 300.degree. C., of perylene-3,4,9,10-tetracarboxylic dianhydride or a monoanhydride monoimide of the formula (2) ##STR2## in which R.sub.2 has the abovementioned meaning, with an arylamine of the formula (3)R.sub.1 --NH.sub.2 (3)in which R.sub.1 has the abovementioned meaning, in the presence of dialkylamines of the formula (4) ##STR3## in which R' and R" denote straight-chain alkyl .sub.C.sbsb.1.sub.- C.sbsb.6 or branched alkyl .sub.C.sbsb.3.sub.-C.sbsb.6 or cycloalkyl .sub.C.sbsb.5.sub.-C.sbsb.

Abstract: A process for the preparation of perylene-3,4,9,10-tetracarboxylic acid N,N'-dimethylimide in a high-hiding pigmentary form and a pure red shade, in which a finely divided, dry perylene-3,4,9,10-tetracarboxylic acid, N,N'-dimethylimide prepigment which is prepared in a conventional manner and has a crystallite size of <400 .ANG. is treated with an organic solvent which is liquid in the treatment temperature range stated below and is selected from the series comprising saturated aliphatic brominated or chlorinated hydrocarbons, aromatic hydrocarbons and aromatic brominated or chlorinated hydrocarbons, in a mill or a disperser at temperatures from 0.degree. C. to 100.degree. C., the organic solvent is then distilled off and the perylene-3,4,9,10-tetracarboxylic acid N,N'-dimethylimide pigment is isolated.

Abstract: Process for preparing perylenetetracarbimide mix-crystal pigments in the crystal lattice of the .alpha.-modification of the N,N'-bis-3',5'-dimethylphenylperylenetetracarbimide of the formula (1) comprising essentially symmetrical N,N'-bis-3',5'-dimethylphenylperylenetetracarbimide of the formula (1) and at least one asymmetrically substituted diimide of the formula (2) in which R stands for methyl or ethyl ##STR1## by condensing 1 mole of perylenetetracarboxylic dianhydride with an excess of up to 30 moles of 3,5-dimethylaniline which contains in total 0.5-6 percent by weight of 4-ethoxyaniline, and their use for coloring organic polymers.

Abstract: A process for preparing the high-hiding form of the .gamma.-crystal modification of unsubstituted linear transquinacridone having improved tinctorial strength and producing a coating of higher gloss, which comprises carrying out (a) the known cyclization of 2,5-diphenylaminoterephthalic acid in highly concentrated polyphosphoric acid or in acid polyphosphoric acid ester to the quinacridone and/or (b) the known hydrolysis of the quinacridone melt obtained in (a) and/or (c) the known aqueous alkali extraction of the quinacridone obtained in (b) and/or (d) the known finishing of the quinacridone obtained in (a) in the presence of 0.5 to 10 percent by weight, based on quinacridone, of surface-active agents.

Abstract: Process for the preparation of linear quinacridones of the formula (1) ##STR1## in which R denotes a hydrogen, fluorine, chlorine or bromine atom or a C.sub.1 -C.sub.6 -alkyl, C.sub.1 -C.sub.3 -alkoxy or phenyl group or a fused benzene ring or a phenylamino or phenoxy group which can be substituted on the aromatic nucleus by fluorine, chlorine or bromine atoms or C.sub.1 -C.sub.4 -alkyl groups, and n denotes a number from 0 to 2, it being possible, in the event that n.noteq.0, for the substituents R present on the same benzene ring or on the two benzene rings to be identical or different, by the oxidation of linear 6,13-dihydroquinacridones of the formula (2) ##STR2## in which R and n have the meanings mentioned above, which comprises heating, at temperatures from about 180.degree. C. to about 280.degree. C., 1 mole of the last-mentioned compounds with 1 to 2 moles of iodine in a high-boiling organic solvent which is inert towards the reactants.

Abstract: Perylenetetracarbimide mix-crystal pigments in the crystal lattice of the .alpha.- Modification of N,N'-bis-3',5'-dimethylphenylperylenetetracarbimide of the formula (1) comprising 98-70 mole percent of the symmetrical diimide of the formula (1) and correspondingly 2-30 mole percent of at least one asymmetrical diimide of the formula (2) ##STR1## in which R denotes a hydrogen atom or a methyl group.

Abstract: Powdered pigments which contain at least 5% of unsubstituted quinacridone and have improved rheological properties for use in paint systems on an alkyd/melamine, acrylic/melamine, acrylate/isocyanate or polyester/isocyanate basis, both of a conventional nature and also of a modern nature of the "high solids" type, onto which--as appropriate before, during or after finishing--1 to 20% by weight of the active substance of a paint additive, prepared by reacting polyisocyanurates which still carry free isocyanate groups and are based on tolylene diisocyanate, hexamethylene diisocyanate or mixtures thereof, with (1) aliphatic mono- or poly-(hydroxycarboxylic acid) C.sub.1 -C.sub.20 -alkyl esters (degree of polymerization 2-50), (2) polyethylene glycols (molecular weight 500-1,500) and (3) 5- or 6-membered, saturated or unsaturated heterocyclic compounds which contain at least 1 nitrogen atom in the ring and reactive amino or hydroxy-C.sub.1 -C.sub.

Abstract: An electrophotographic recording material comprises an electrically conductive base material, an optional insulating intermediate layer and a photoconductive layer comprising at least one layer containing an asymmetrically substituted perylene-3,4,9,10-tetracarboxylic acid imide as charge carrier producing compound, a photoconductor as charge transport compound, binder and customary additives. The asymmetrically substituted perylene-3,4,9,10-tetracarboxylic acid imide can, for example, be represented by the formula ##STR1## where R denotes hydrogen, alkyl, hydroxyalky, alkoxyalkyl, aryl or aralkyl and A denotes phenylene, naphthylene or a more highly fused aromatic carbocylic or heterocyclic radical which can each be substituted by halogen, alkyl, cyano or nitro groups. This material is suitable in double-layer arrangement for highly light sensitive systems, and in a single layer for preparing printing forms or printed circuits.

Abstract: Compounds of the formula ##STR1## in which R denotes hydrogen, hydroxyl, amino or optionally substituted alkyl, X denotes chlorine or bromine and n is a number from zero to 4, are obtained from the corresponding mono-alkali metal salts of perylene-3,4,9,10-tetracarboxylic acid monoanhydrides by reaction with compounds of the formula R-NH.sub.2, in which R has the above meaning, at 0.degree.-130.degree. C. The compounds are colorants or starting materials for colorants.

Abstract: Process for the preparation of pigments of the anthanthrone series of the formula ##STR1## in which R.sub.1 and R.sub.2 denote chlorine, bromine or iodine atoms or C.sub.1 -C.sub.4 -alkoxy groups, having valuable properties, which comprises first converting the anthanthrones of the formula mentioned, in the form of the crude pigment, in an aqueous alkaline medium and at a pH>10, into the leucoform, precipitating the latter by adding inorganic or organic acids, reoxidizing the aqueous suspension of the leuco-form to give the anthanthrones and subjecting the resulting finely divided pre-pigments of the formula mentioned to a solvent finish.

Abstract: Pigments of the quinacridonequinone series comprising 99-30 mole percent of a quinacridonequinone of the formula (1) ##STR1## in which R denotes a hydrogen or chlorine atom or a methyl group, 0-60 mole percent of a quinacridone of the formula (2) ##STR2## in which R has the above-mentioned meaning, and 1-10 mole percent of a 7,15-dihydro-pyrido-(2,1-b)-(1',2'; 1,2)-pyrimido-(4,5-g)-quinazoline-7,15-dione of the formula (3) ##STR3## in which R has the above-mentioned meaning, the added compounds of the formulae (2) and (3) being present in the crystal lattice of the quinacridonequinone of the formula (1), process for their preparation and their use for coloring plastic materials and for preparing automotive paints for metallic coatings.

Abstract: A process for the preparation of 4,4',7,7'-tetrachloro-thioindigo pigment which comprises treating a finely divided crude 4,4',7,7'-tetrachloro-thioindigo pigment in anhydrous form at temperatures of from 50.degree. to 180.degree. C. with a nitroaromatic substance which is volatile in steam and has a melting point of 50.degree. C. or below under normal conditions.

Abstract: Process for preparing 1,3,6,8-tetrabromopyrene by brominating pyrene in aqueous suspension with simultaneous reoxidation of the resulting hydrogen bromide to bromine by means of an oxidizing agent, which comprises reacting pyrene in a highly concentrated aqueous suspension having a pyrene-water weight ratio of 1:1.2 to 2 with bromine at temperatures of 40.degree. to 65.degree. C. with simultaneous reoxidation of the resulting hydrogen bromide to bromine using an oxidizing agent, completing the bromination by heating the reaction mixture to temperatures of 70.degree. to 130.degree. C., reducing excess bromine with a reducing agent to hydrogen bromide and subjecting the 1,3,6,8-tetrabromopyrene formed, preferably without intermediate isolation, to an alkaline aftertreatment at temperatures of 40.degree. to 100.degree. C. within the pH range 8.5 to 12.

Abstract: Process for preparing organic pigments having excellent application properties, which comprises treating finely divided crude pigments of the anthanthrone, pyranthrone, isoviolanthrone, azo, quinacridone, flavanthrone, indanthrone, naphthaldazine, indigo, thioindigo, tetracarboximide, dioxazine, isoindolinone, perylene, anthrapyrimidine, acylanthraquinone, dianthraquinonyl, azoanthraquinone, azomethineanthraquinone and phthalocyanine series at temperatures of 0.degree. C. to 100.degree. C., with acid esters of polyphosphoric acid and a primary, secondary or tertiary alkanol of 1 to 8 carbon atoms, a glycol, glycol ether or phenol, then hydrolyzing the polyphosphate ester used, heating the resultant aqueous mixture to temperatures of 20.degree. C. to 150.degree. C., and isolating the pigment in conventional manner.

Abstract: Process for the preparation of perylene-3,4,9,10-tetracarboxylic dianhydride of high purity and in a very good yield in an ecologically unobjectionable manner, which comprises saponifying perylene-3,4,9,10-tetracarboxylic acid diimide with a 2.5-fold to 6-fold amount by weight of 92.5% to 97.5% strength sulfuric acid at temperatures of 210.degree. to 230.degree. C.

Abstract: Process for preparing a strong, non-flocking and rheologically excellent 4,4',7,7'-tetrachlorothioindigo pigment in high yields and high purity, which comprises(a) reacting 2,5 -dichlorophenylthioglycoloyl chloride with Friedel-Crafts catalysts in inorganic acyl halides of medium oxidation state as diluent as temperatures of -20.degree. to +50.degree. C. to 4,7-dichloro-3-oxythionaphthene,(b) oxidizing the resulting 4,7-dichloro-3-oxythionaphthene in a conventional manner to crude 4,4',7,7'-tetrachlorothioindigo, and(c) treating the crude 4,4',7,7'-tetrachlorothioindigo obtained in moist form with an aromatic solvent at 80.degree. to 180.degree. C. in the presence of an aqueous alkali solution and a surface-active compound.

Abstract: Process for the preparation of dry alkali metal salts of 1,8-naphthalimide, which comprises allowing concentrated alkali metal hydroxide solutions to run into solid 1,8-naphthalimide in a molar ratio, at a rate corresponding to the degree of reaction, with vigorous stirring in vacuo at an elevated internal temperature, and then carrying out drying without intermediate isolation of the alkali metal salt formed.

Abstract: Compounds of the formula ##STR1## in which R denotes hydrogen, hydroxyl, amino or optionally substituted alkyl, X denotes chlorine or bromine and n is a number from zero to 4, are obtained from the corresponding mono-alkali metal salts of perylene-3,4,9,10-tetracarboxylic acid monoanhydrides by reaction with compounds of the formula R--NH.sub.2, in which R has the above meaning, at 0.degree.-130.degree. C. The compounds are colorants or starting materials for colorants.

Abstract: Process for the preparation of naphthalene-1,4,5,8-tetracarboxylic acid (called "NTC" below) and its 1,8-monoanhydride in a high degree of purity, which comprises dissolving impure NTC or impure NTC-1,8-monoanhydride as the tetra-alkali metal salt of NTC in water in known manner, removing any insoluble impurities present, bringing the clarified solution to a pH value of 4-5 below 45.degree. C., separating off the di-alkali metal salt of NTC which thereby crystallizes out and converting the latter into free NTC or into free NTC-1,8-monoanhydride by treatment with a strong acid at 20.degree. to 100.degree. C.